Publications

@article{nokey,

title = {Operando Study of Structure Degradation in Solid-State Dye-Sensitized Solar Cells with a TiO2 Photoanode Having Ordered Mesopore Arrays},

author = {N Li and R Guo and A L Oechsle and M A Reus and S Liang and L Song and K Wang and D Yang and F Allegretti and A Kumar and M Nuber and J Berger and S Bernstorff and H Iglev and J Hauer and R A Fischer and J V Barth and P M\"{u}ller-Buschbaum},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/solr.202200373},

doi = {https://doi.org/10.1002/solr.202200373},

issn = {2367-198X},

year  = {2022},

date = {2022-05-31},

journal = {Solar RRL},

volume = {n/a},

number = {n/a},

pages = {2200373},

abstract = {Via operando grazing-incidence small-angle X-ray scattering, the degradation mechanisms of solid-state dye-sensitized solar cells (ssDSSCs) using two types of ordered mesoporous TiO2 scaffolds with different pore sizes, and an exemplary dye D205, are investigated. The temporal evolution of the inner morphology shows a strong impact on device performance. The photoinduced dye aggregation on the TiO2 surface leads to an increase in the domain radius but a decreased spatial order of the photoactive layer during the burn-in stage. This dye aggregation on the TiO2 surface causes the short-circuit current density loss, which plays a major role in the power conversion efficiency decay. Finally, it is found that a larger surface area in the small-pore sample yields a faster short-circuit current density decay as compared with the big-pore sample. Therefore, a control of dye aggregation and the pore size of TiO2 photoelectrodes is crucial for the stability of TiO2-based ssDSSCs.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Advances in nano-and microscale NMR spectroscopy using diamond quantum sensors},

author = {R D Allert and K D Briegel and D B Bucher},

url = {https://arxiv.org/abs/2205.12178},

doi = {https://doi.org/10.48550/arXiv.2205.12178},

year  = {2022},

date = {2022-05-24},

journal = {arXiv preprint arXiv:2205.12178},

abstract = {Quantum technologies have seen a rapid developmental surge over the last couple of years. Though often overshadowed by quantum computation, quantum sensors show tremendous potential for widespread applications in chemistry and biology. One system stands out in particular: the nitrogen-vacancy (NV) center in diamond, an atomic-sized sensor allowing the detection of nuclear magnetic resonance (NMR) signals at unprecedented length scales down to a single proton. In this article, we review the fundamentals of NV center-based quantum sensing and its distinct impact on nano- to microscale NMR spectroscopy. Furthermore, we highlight and discuss possible future applications of this novel technology ranging from energy research, material science, or single-cell biology, but also associated challenges of these rapidly developing NMR sensors.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Understanding Carotenoid Dynamics via the Vibronic Energy Relaxation Approach},

author = {V \v{S}ebel\'{i}k and C D P Duffy and E Keil and T Pol\'{i}vka and J Hauer},

url = {https://doi.org/10.1021/acs.jpcb.2c00996},

doi = {10.1021/acs.jpcb.2c00996},

issn = {1520-6106},

year  = {2022},

date = {2022-05-24},

journal = {The Journal of Physical Chemistry B},

abstract = {Carotenoids are an integral part of natural photosynthetic complexes, with tasks ranging from light harvesting to photoprotection. Their underlying energy deactivation network of optically dark and bright excited states is extremely efficient: after excitation of light with up to 2.5 eV of photon energy, the system relaxes back to ground state on a time scale of a few picoseconds. In this article, we summarize how a model based on the vibrational energy relaxation approach (VERA) explains the main characteristics of relaxation dynamics after one-photon excitation with special emphasis on the so-called S* state. Lineshapes after two-photon excitation are beyond the current model of VERA. We outline this future line of research in our article. In terms of experimental method development, we discuss which techniques are needed to better describe energy dissipation effects in carotenoids and within the first solvation shell.},

keywords = {Foundry Inorganic, Solid-Liquid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Capabilities and limitations of rotating disk electrodes versus membrane electrode assemblies in the investigation of electrocatalysts},

author = {T Lazaridis and B M St\"{u}hmeier and H A Gasteiger and H A El-Sayed},

url = {https://doi.org/10.1038/s41929-022-00776-5},

doi = {10.1038/s41929-022-00776-5},

issn = {2520-1158},

year  = {2022},

date = {2022-05-23},

journal = {Nature Catalysis},

volume = {5},

number = {5},

pages = {363-373},

abstract = {Cost-competitive fuel cells and water electrolysers require highly efficient electrocatalysts for the respective reactions of hydrogen oxidation and evolution, and oxygen evolution and reduction. Electrocatalyst activity and durability are commonly assessed using rotating disk electrodes (RDEs) or membrane electrode assemblies (MEAs). RDEs provide a quick and widely accessible testing tool, whereas MEA testing is more complex but closely resembles the actual application. Although both experimental set-ups allow investigation of the same reactions, there are scientific questions that cannot be answered by the RDE technique. In this Perspective, we scrutinize protocols widely used to determine the activity and durability of electrocatalysts, and highlight discrepancies in the results obtained using RDEs and MEAs. We discuss where the use of RDEs is appropriate and, conversely, where it leads to erroneous interpretations. Ultimately, we show that many of the current challenges for hydrogen and oxygen electrocatalysts require MEA testing and advocate for its greater adoption in the early stages of electrocatalyst development.},

keywords = {Foundry Inorganic, Solid-Liquid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {All-optical nanoscopic spatial control of molecular reaction yields on nanoparticles},

author = {W Zhang and R Dagar and P Rosenberger and A Sousa-Castillo and M Neuhaus and W Li and S A Khan and A S Alnaser and E Cortes and S A Maier and C Costa-Vera and M F Kling and B Bergues},

url = {http://opg.optica.org/optica/abstract.cfm?URI=optica-9-5-551},

doi = {10.1364/OPTICA.453915},

year  = {2022},

date = {2022-05-20},

journal = {Optica},

volume = {9},

number = {5},

pages = {551-560},

abstract = {Molecular adsorbate reactions on nanoparticles play a fundamental role in areas such as nano-photocatalysis, atmospheric, and astrochemistry. They can be induced, enhanced, and controlled by field localization and enhancement on the nanoparticle surface. In particular, the ability to perform highly controlled near-field-mediated reactions is key to deepening our understanding of surface photoactivity on nanosystems. Here, using reaction nanoscopy, we experimentally demonstrate all-optical nanoscopic control of surface reaction yields by tailoring the near fields on nanoparticles with waveform-controlled linear and bicircular two-color laser pulses, respectively. We observe site-selective proton emission from the dissociative ionization of adsorbate molecules on SiO2 nanoparticles as a function of the polarization and relative phase of the two-color pulses. The angularly resolved close-to-uniform mapping between the surface reaction yields and the measured ion momentum enables the observation and spatial control of molecular reactions on the nanoparticle surface with nanoscopic resolution. The experimental results are modeled and reproduced qualitatively by classical trajectory Monte Carlo simulations. Our work paves the way toward reliable all-optical control of photocatalytic chemical reactions on nanoscale surfaces.},

keywords = {Molecularly-Functionalized, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Effect of Solvent Vapor Annealing on Diblock Copolymer-Templated Mesoporous Si/Ge/C Thin Films: Implications for Li-Ion Batteries},

author = {C L Weindl and C E Fajman and M A Giebel and K S Wienhold and S Yin and T Tian and C Geiger and L P Kreuzer and M Schwartzkopf and S V Roth and T F F\"{a}ssler and P M\"{u}ller-Buschbaum},

url = {https://doi.org/10.1021/acsanm.2c01191},

doi = {10.1021/acsanm.2c01191},

year  = {2022},

date = {2022-05-17},

journal = {ACS Applied Nano Materials},

volume = {5},

number = {5},

pages = {7278-7287},

abstract = {Although amphiphilic diblock copolymer templating of inorganic materials such as TiO2 is already well investigated, sol\textendashgel synthesis routines for porous silicon and germanium are relatively rare. Therefore, especially in the field of Li-ion batteries, novel synthesis routines with the possibility to tune the silicon and germanium ratio and the morphology in the nanometer regime are of high interest. Here, we demonstrate a synthesis method that allows a change of morphology and elemental composition with minimal effort. We evidence a morphological transformation in the nanometer regime with real space (scanning electron microscopy) and complementary reciprocal space analysis methods (grazing-incidence small-angle X-ray scattering). Although energy-dispersive X-ray spectroscopy (EDS) reveals a considerable amount of oxygen in the thin film, crystalline Ge in the bulk is detected with powder X-ray diffraction (PXRD) and Raman spectroscopy. Due to the system’s simplicity, chemical mass production options such as roll-to-roll or slot-die printing can also be considered high-yield methods compared to standard synthesis routines.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Gold\textendashrhodium nanoflowers for the plasmon enhanced ethanol electrooxidation under visible light for tuning the activity and selectivity},

author = {M P S Rodrigues and A H B Dourado and K Krischer and S I C Torresi},

url = {https://www.sciencedirect.com/science/article/pii/S0013468622006016},

doi = {https://doi.org/10.1016/j.electacta.2022.140439},

issn = {0013-4686},

year  = {2022},

date = {2022-05-12},

journal = {Electrochimica Acta},

volume = {420},

pages = {140439},

abstract = {Direct ethanol fuel cells (DEFCs) are a promising power source, but the low selectivity to ethanol complete oxidation is still challenging. The localized surface plasmon resonance (LSPR) excitation has been reported to accelerate and drive several chemical reactions, including the ethanol oxidation reaction (EOR), coming as a strategy to improve catalysts performance. Nonetheless, metallic nanoparticles (NPs) that present the LSPR excitation in the visible range are known for leading to the incomplete oxidation of ethanol. Thus, we report here the application of gold-rhodium nanoflowers (Au@Rh NFs) towards the plasmon-enhanced EOR. These hybrid materials consist of a Au spherical nucleus covered by Rh branches shell, combining plasmonic and catalytic properties. Firstly, the Au@Rh NFs metallic ratio was investigated in dark conditions to obtain an optimal catalyst. Experiments were also performed under light irradiation. Our data demonstrated an improvement of 352% in current density and 36% in selectivity to complete ethanol oxidation under 533 nm laser incidence. Moreover, the current density showed a linear increase with the laser power density, indicating a photochemical effect and thus enhancement due to the LSPR properties.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Controlling Plasmonic Chemistry Pathways through Specific Ion Effects},

author = {A Stefancu and L Nan and L Zhu and V Chiș and I Bald and M Liu and N Leopold and S A Maier and E Cortes},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adom.202200397},

doi = {https://doi.org/10.1002/adom.202200397},

issn = {2195-1071},

year  = {2022},

date = {2022-05-11},

journal = {Advanced Optical Materials},

volume = {n/a},

number = {n/a},

pages = {2200397},

abstract = {Abstract Plasmon-driven dehalogenation of brominated purines has been recently explored as a model system to understand fundamental aspects of plasmon-assisted chemical reactions. Here, it is shown that divalent Ca2+ ions strongly bridge the adsorption of bromoadenine (Br-Ade) to Ag surfaces. Such ion-mediated binding increases the molecule's adsorption energy leading to an overlap of the metal energy states and the molecular states, enabling the chemical interface damping (CID) of the plasmon modes of the Ag nanostructures (i.e., direct electron transfer from the metal to Br-Ade). Consequently, the conversion of Br-Ade to adenine almost doubles following the addition of Ca2+. These experimental results, supported by theoretical calculations of the local density of states of the Ag/Br-Ade complex, indicate a change of the charge transfer pathway driving the dehalogenation reaction, from Landau damping (in the lack of Ca2+ ions) to CID (after the addition of Ca2+). The results show that the surface dynamics of chemical species (including water molecules) play an essential role in charge transfer at plasmonic interfaces and cannot be ignored. It is envisioned that these results will help in designing more efficient nanoreactors, harnessing the full potential of plasmon-assisted chemistry.},

keywords = {Molecularly-Functionalized, Solid-Liquid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Inverse Multislice Ptychography by Layer-wise Optimisation and Sparse Matrix Decomposition},

author = {A Bangun and O Melnyk and B M\"{a}rz and B Diederichs and A Clausen and D Weber and F Filbir and K M\"{u}ller-Caspary},

url = {https://arxiv.org/abs/2205.03902},

doi = {https://doi.org/10.48550/arXiv.2205.03902},

year  = {2022},

date = {2022-05-08},

journal = {arXiv preprint arXiv:2205.03902},

abstract = {We propose algorithms based on an optimisation method for inverse multislice ptychography in, e.g. electron microscopy. The multislice method is widely used to model the interaction between relativistic electrons and thick specimens. Since only the intensity of diffraction patterns can be recorded, the challenge in applying inverse multislice ptychography is to uniquely reconstruct the electrostatic potential in each slice up to some ambiguities. In this conceptual study, we show that a unique separation of atomic layers for simulated data is possible when considering a low acceleration voltage. We also introduce an adaptation for estimating the illuminating probe. For the sake of practical application, we finally present slice reconstructions using experimental 4D scanning transmission electron microscopy (STEM) data.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Electronic and Optical Properties of Eu2+-Activated Narrow-Band Phosphors for Phosphor-Converted Light-Emitting Diode Applications: Insights from a Theoretical Spectroscopy Perspective},

author = {R Shafei and D Maganas and P J Strobel and P J Schmidt and W Schnick and F Neese},

url = {https://doi.org/10.1021/jacs.2c00218},

doi = {10.1021/jacs.2c00218},

issn = {0002-7863},

year  = {2022},

date = {2022-04-26},

journal = {Journal of the American Chemical Society},

volume = {144},

number = {18},

pages = {8038-8053},

abstract = {In this work, we present a computational protocol that is able to predict the experimental absorption and emission spectral shapes of Eu2+-doped phosphors. The protocol is based on time-dependent density functional theory and operates in conjunction with an excited-state dynamics approach. It is demonstrated that across the study set consisting of representative examples of nitride, oxo-nitride, and oxide Eu2+-doped phosphors, the energy distribution and the band shape of the emission spectrum are related to the nature of the 4f\textendash5d transitions that are probed in the absorption process. Since the 4f orbitals are very nearly nonbonding, the decisive quantity is the covalency of the 5d acceptor orbitals that become populated in the electronically excited state that leads to emission. The stronger the (anti) bonding interaction between the lanthanide and the ligands is in the excited state, the larger will be the excited state distortion. Consequently, the corresponding emission will get broader due to the vibronic progression that is induced by the structural distortion. In addition, the energy separation of the absorption bands that are dominated by states with valence 4f\textendash5d and a metal to ligand charge transfer character defines a measure for the thermal quenching of the studied Eu2+-doped phosphors. Based on this analysis, simple descriptors are identified that show a strong correlation with the energy position and bandwidth of the experimental emission bands without the need for elaborate calculations. Overall, we believe that this study serves as an important reference for designing new Eu2+-doped phosphors with desired photoluminescence properties.},

keywords = {Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Solution-based synthesis of wafer-scale epitaxial BiVO4 thin films exhibiting high structural and optoelectronic quality},

author = {V F Kunzelmann and C-M Jiang and I Ihrke and E Sirotti and T Rieth and A Henning and J Eichhorn and I D Sharp},

url = {http://dx.doi.org/10.1039/D1TA10732A},

doi = {10.1039/D1TA10732A},

issn = {2050-7488},

year  = {2022},

date = {2022-04-22},

journal = {Journal of Materials Chemistry A},

abstract = {We demonstrate a facile approach to solution-based synthesis of wafer-scale epitaxial bismuth vanadate (BiVO4) thin films by spin-coating on yttria-stabilized zirconia. Epitaxial growth proceeds via solid-state transformation of initially formed polycrystalline films, driven by interface energy minimization. The (010)-oriented BiVO4 films are smooth and compact, possessing remarkably high structural quality across complete 2′′ wafers. Optical absorption is characterized by a sharp onset with a low sub-band gap response, confirming that the structural order of the films results in correspondingly high optoelectronic quality. This combination of structural and optoelectronic quality enables measurements that reveal a strong optical anisotropy of BiVO4, which leads to significantly increased in-plane optical constants near the fundamental band edge that are of particular importance for maximizing light harvesting in semiconductor photoanodes. Temperature-dependent transport measurements confirm a thermally activated hopping barrier of ∼570 meV, consistent with small electron polaron conduction. This simple approach for synthesis of high-quality epitaxial BiVO4, without the need for complex deposition equipment, enables a broadly accessible materials base to accelerate research aimed at understanding and optimizing photoelectrochemical energy conversion mechanisms.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Revealing the Nature of Active Sites on Pt\textendashGd and Pt\textendashPr Alloys during the Oxygen Reduction Reaction},

author = {R M Kluge and E Psaltis and R W Haid and S Hou and T O Schmidt and O Schneider and B Garlyyev and F Calle-Vallejo and A S Bandarenka},

url = {https://doi.org/10.1021/acsami.2c03604},

doi = {10.1021/acsami.2c03604},

issn = {1944-8244},

year  = {2022},

date = {2022-04-20},

journal = {ACS Applied Materials \& Interfaces},

volume = {14},

number = {17},

pages = {19604-19613},

abstract = {For large-scale applications of hydrogen fuel cells, the sluggish kinetics of the oxygen reduction reaction (ORR) have to be overcome. So far, only platinum (Pt)-group catalysts have shown adequate performance and stability. A well-known approach to increase the efficiency and decrease the Pt loading is to alloy Pt with other metals. Still, for catalyst optimization, the nature of the active sites is crucial. In this work, electrochemical scanning tunneling microscopy (EC-STM) is used to probe the ORR active areas on Pt5Gd and Pt5Pr in acidic media under reaction conditions. The technique detects localized fluctuations in the EC-STM signal, which indicates differences in the local activity. The in situ experiments, supported by coordination\textendashactivity plots based on density functional theory calculations, show that the compressed Pt\textendashlanthanide (111) terraces contribute the most to the overall activity. Sites with higher coordination, as found at the bottom of step edges or concavities, remain relatively inactive. Sites of lower coordination, as found near the top of step edges, show higher activity, presumably due to an interplay of strain and steric hindrance effects. These findings should be vital in designing nanostructured Pt\textendashlanthanide electrocatalysts.},

keywords = {Foundry Inorganic},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Introducing a Symmetry-Breaking Coupler into a Dielectric Metasurface Enables Robust High-Q Quasibound States in the Continuum and Efficient Nonlinear Frequency Conversion},

author = {G Q Moretti and A Tittl and E Cort\'{e}s and S A Maier and A V Bragas and G Grinblat},

url = {https://doi.org/10.48550/arXiv.2204.07097},

doi = {https://doi.org/10.48550/arXiv.2204.07097},

year  = {2022},

date = {2022-04-14},

journal = {arXiv preprint arXiv:2204.07097},

abstract = {Dielectric metasurfaces supporting quasi-bound states in the continuum (quasi-BICs) exhibit very high quality factor resonances and electric field confinement. However, accessing the high-Q end of the quasi-BIC regime usually requires marginally distorting the metasurface design from a BIC condition, pushing the needed nanoscale fabrication precision to the limit. This work introduces a novel concept for generating high-Q quasi-BICs, which strongly relaxes this requirement by incorporating a relatively large perturbative element close to high-symmetry points of an undistorted BIC metasurface, acting as a coupler to the radiation continuum. We validate this approach by adding a ∼100 nm diameter cylinder between two reflection-symmetry points separated by a 300 nm gap in an elliptical disk metasurface unit cell, using gallium phosphide as the dielectric. We find that high-Q resonances emerge when the cylindrical coupler is placed at any position between such symmetry points. We further explore this metasurface's second harmonic generation capability in the optical range. Displacing the coupler as much as a full diameter from a BIC condition produces record-breaking normalized conversion efficiencies >102 W−1. The strategy of enclosing a disruptive element between multiple high-symmetry points in a BIC metasurface could be applied to construct robust high-Q quasi-BICs in many geometrical designs.},

keywords = {Foundry Inorganic, Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Spatially Resolved Electrochemical Impedance Spectroscopy of Automotive PEM Fuel Cells},

author = {A S Bandarenka and F Haimerl and J P Sabawa and T A Dao},

url = {https://chemistry-europe.onlinelibrary.wiley.com/doi/abs/10.1002/celc.202200069},

doi = {https://doi.org/10.1002/celc.202200069},

issn = {2196-0216},

year  = {2022},

date = {2022-04-13},

urldate = {2022-04-13},

journal = {ChemElectroChem},

volume = {n/a},

number = {n/a},

abstract = {Fuel cell electric vehicles (FCEVs), which use polymer electrolyte membrane fuel cells (PEMFCs), provide a prospect to add to a future mobility. However, an in-depth understanding of degradation mechanisms and contributions to performance losses is needed to commercialize FCEVs further. Previous PEMFC degradation research has focused on global indicators of the cell condition. Failure occurs typically due to inhomogeneities in operation, leading to localized regions of high degradation rates. Here, we present the results of a comprehensive study of spatial distributions of essential PEMFC parameters using electrochemical impedance spectroscopy across the cell surface of automotive-size fuel cells with an active area of 285cm2. In particular, the results reveal increasing mass transport problems with increasing distance from the air inlet and a tendency of lower proton resistances in the center of the cell. One hundred twenty realistic freeze-start cycles degenerated the cell performance drastically. The outer cell regions, subject to the lowest temperatures, showed the most substantial degradation rates, partly compensated by central cell regions with slightly higher temperatures. These findings bridge the gap between simulation and experiment and provide valuable insights for future fuel cell design and operating strategies.},

keywords = {Solid-Liquid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Li+ Conductivity of Space Charge Layers Formed at Electrified Interfaces Between a Model Solid-State Electrolyte and Blocking Au-Electrodes},

author = {L Katzenmeier and L Carstensen and A S Bandarenka},

url = {https://doi.org/10.1021/acsami.2c00650},

doi = {10.1021/acsami.2c00650},

issn = {1944-8244},

year  = {2022},

date = {2022-04-06},

journal = {ACS Applied Materials \& Interfaces},

volume = {14},

number = {13},

pages = {15811-15817},

abstract = {The formation of space charge layers in solid-state ion conductors has been investigated as early as the 1980s. With the advent of all-solid-state batteries as an alternative to traditional Li-ion batteries, possibly improving performance and safety, the phenomenon of space charge formation caught the attention of researchers as a possible origin for the observed high interfacial resistance. Following classical space charge theory, such high resistances result from the formation of the depletion layers. These layers of up to hundreds of nanometers in thickness are almost free of mobile cations. With the prediction of a Debye-like screening effect, the thickness of the depletion layer is expected to scale with the square root of the absolute temperature. In this work, we studied the temperature dependence of the depletion layer properties in model solid Ohara LICGC Li+ conducting electrolytes using electrochemical impedance spectroscopy. We show that the activation energy inside the depletion layer increases to ca 0.42 eV compared to ca 0.39 eV in the bulk electrolyte. Moreover, the proportionality between temperature and depletion layer thickness, correlating to the Debye length, is tested and validated.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Selective and Cooperative Photocycloadditions within Multistranded Aromatic Sheets},

author = {B Gole and B Kauffmann and A Tron and V Maurizot and N Mcclenaghan and I Huc and Y Ferrand},

url = {https://doi.org/10.1021/jacs.2c01269},

doi = {10.1021/jacs.2c01269},

issn = {0002-7863},

year  = {2022},

date = {2022-04-05},

journal = {Journal of the American Chemical Society},

abstract = {A series of aromatic helix-sheet-helix oligoamide foldamers composed of several different photosensitive diazaanthracene units have been designed and synthesized. Molecular objects up to 7 kDa were straightforwardly produced on a 100 mg scale. Nuclear magnetic resonance and crystallographic investigations revealed that helix-sheet-helix architectures can adopt one or two distinct conformations. Sequences composed of an even number of turn units were found to fold in a canonical symmetrical conformation with two helices of identical handedness stacked above and below the sheet segment. Sequences composed of an odd number of turns revealed a coexistence between a canonical fold with helices of opposite handedness and an alternate fold with a twist within the sheet and two helices of identical handedness. The proportions between these species could be manipulated, in some cases quantitatively, being dependent on solvent, temperature, and absolute control of helix handedness. Diazaanthracene units were shown to display distinct reactivity toward [4 + 4] photocycloadditions according to the substituent in position 9. Their organization within the sequences was programmed to allow photoreactions to take place in a specific order. Reaction pathways and kinetics were deciphered and product characterized, demonstrating the possibility to orchestrate successive photoreactions so as to avoid orphan units or to deliberately produce orphan units at precise locations. Strong cooperative effects were observed in which the photoreaction rate was influenced by the presence (or absence) of photoadducts in the structure. Multiple photoreactions within the aromatic sheet eventually lead to structure lengthening and stiffening, locking conformational equilibria. Photoproducts could be thermally reverted.},

keywords = {Foundry Organic, Molecularly Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {High-Throughput Fabrication of Triangular Nanogap Arrays for Surface-Enhanced Raman Spectroscopy},

author = {S Luo and A Mancini and F Wang and J Liu and S A Maier and J C De Mello},

url = {https://doi.org/10.1021/acsnano.1c09930},

doi = {10.1021/acsnano.1c09930},

issn = {1936-0851},

year  = {2022},

date = {2022-04-05},

journal = {ACS Nano},

abstract = {Squeezing light into nanometer-sized metallic nanogaps can generate extremely high near-field intensities, resulting in dramatically enhanced absorption, emission, and Raman scattering of target molecules embedded within the gaps. However, the scarcity of low-cost, high-throughput, and reproducible nanogap fabrication methods offering precise control over the gap size is a continuing obstacle to practical applications. Using a combination of molecular self-assembly, colloidal nanosphere lithography, and physical peeling, we report here a high-throughput method for fabricating large-area arrays of triangular nanogaps that allow the gap width to be tuned from ∼10 to ∼3 nm. The nanogap arrays function as high-performance substrates for surface-enhanced Raman spectroscopy (SERS), with measured enhancement factors as high as 108 relative to a thin gold film. Using the nanogap arrays, methylene blue dye molecules can be detected at concentrations as low as 1 pM, while adenine biomolecules can be detected down to 100 pM. We further show that it is possible to achieve sensitive SERS detection on binary-metal nanogap arrays containing gold and platinum, potentially extending SERS detection to the investigation of reactive species at platinum-based catalytic and electrochemical surfaces.},

keywords = {Foundry Inorganic},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Transversal Halide Motion Intensifies Band-To-Band Transitions in Halide Perovskites},

author = {C Gehrmann and S Caicedo-D\'{a}vila and X Zhu and D A Egger},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/advs.202200706},

doi = {https://doi.org/10.1002/advs.202200706},

issn = {2198-3844},

year  = {2022},

date = {2022-04-04},

journal = {Advanced Science},

volume = {n/a},

number = {n/a},

pages = {2200706},

abstract = {Abstract Despite their puzzling vibrational characteristics that include strong signatures of anharmonicity and thermal disorder already around room temperature, halide perovskites (HaPs) exhibit favorable optoelectronic properties for applications in photovoltaics and beyond. Whether these vibrational properties are advantageous or detrimental to their optoelectronic properties remains, however, an important open question. Here, this issue is addressed by investigation of the finite-temperature optoelectronic properties in the prototypical cubic CsPbBr3, using first-principles molecular dynamics based on density-functional theory. It is shown that the dynamic flexibility associated with HaPs enables the so-called transversality, which manifests as a preference for large halide displacements perpendicular to the Pb-Br-Pb bonding axis. The authors find that transversality is concurrent with vibrational anharmonicity and leads to a rapid rise in the joint density of states, which is favorable for photovoltaics since this implies sharp optical absorption profiles. These findings are contrasted to the case of PbTe, a material that shares several key properties with CsPbBr3 but cannot exhibit any transversality and, hence, is found to exhibit much wider band-edge distributions. The authors conclude that the dynamic structural flexibility in HaPs and their unusual vibrational characteristics might not just be a mere coincidence, but play active roles in establishing their favorable optoelectronic properties.},

keywords = {Foundry Inorganic},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Time-Resolved Orientation and Phase Analysis of Lead Halide Perovskite Film Annealing Probed by In Situ GIWAXS},

author = {M A Reus and L K Reb and A F Weinzierl and C L Weindl and R Guo and T Xiao and M Schwartzkopf and A Chumakov and S V Roth and P M\"{u}ller-Buschbaum},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adom.202102722},

doi = {https://doi.org/10.1002/adom.202102722},

issn = {2195-1071},

year  = {2022},

date = {2022-04-03},

journal = {Advanced Optical Materials},

volume = {n/a},

number = {n/a},

pages = {2102722},

abstract = {Abstract Scalable thin-film deposition methods are increasingly important for hybrid lead halide perovskite thin films. Understanding the structure evolution during non-equilibrium processes helps to find suitable materials and processing parameters to produce films with well-performing optoelectronic properties. Here, spin-cast and slot-die coated bilayers of lead iodide (PbI2) and methylammonium iodide (MAI) are investigated by in situ grazing-incidence wide-angle X-ray scattering during the thermal annealing process, which converts the bilayer into methylammonium lead iodide (MAPI). Photoluminescence (PL) and UV/Vis measurements show increasing crystallinity during the annealing process and a slight PL red-shift of the spin-cast film, attributed to crystallite coalescence that is not prominent for the slot-die coated film. The disintegration of the solvent-precursor complex (MA)2(Pb3I8) ⋅ 2 DMSO and conversion into perovskite are followed in situ and differences in the morphology and time evolution are observed. In both, spin-cast and slot-die coated thin-films, the isotropic orientation is dominant, however, in the slot-die coated films, the perovskite crystallites have an additional face-on orientation ((110) parallel to substrate) that is not detected in spin-cast films. An Avrami model is applied for the perovskite crystal growth that indicates reduced dimensionality of the growth for the printed thin films.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Selectivity Trends and Role of Adsorbate-Adsorbate Interactions in CO Hydrogenation on Rhodium Catalysts},

author = {M Deimel and H Prats and M Seibt and K Reuter and M Andersen},

url = {https://arxiv.org/abs/2203.15746},

doi = {https://doi.org/10.48550/arXiv.2203.15746},

year  = {2022},

date = {2022-03-29},

journal = {arXiv preprint arXiv:2203.15746},

abstract = {Predictive-quality computational modeling of heterogeneously catalyzed reactions has emerged as an important tool for the analysis and assessment of activity and activity trends. In contrast, more subtle selectivities and selectivity trends still pose a significant challenge to prevalent microkinetic modeling approaches that typically employ a mean-field approximation (MFA). Here, we focus on CO hydrogenation on Rh catalysts with the possible products methane, acetaldehyde, ethanol and water. This reaction has already been subject to a number of experimental and theoretical studies with conflicting views on the factors controlling activity and selectivity towards the more valuable higher oxygenates. Using accelerated first-principles kinetic Monte Carlo (KMC) simulations and explicitly and systematically accounting for adsorbate-adsorbate interactions through a cluster expansion approach, we model the reaction on the low-index Rh(111) and stepped Rh(211) surfaces. We find that the Rh(111) facet is selective towards methane, while the Rh(211) facet exhibits a similar selectivity towards methane and acetaldehyde. This is consistent with the experimental selectivity observed for larger, predominantly (111)-exposing Rh nanoparticles and resolves the discrepancy to earlier first-principles MFA microkinetic work that found the Rh(111) facet to be selective towards acetaldehyde. While the latter work tried to approximately account for lateral interactions through coverage-dependent rate expressions, our analysis demonstrates that this fails to sufficiently capture concomitant correlations among the adsorbed reaction intermediates that crucially determine the overall selectivity.},

keywords = {Foundry Inorganic, Solid-Liquid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Wafer-scale epitaxial modulation of quantum dot density},

author = {N Bart and C Dangel and P Zajac and N Spitzer and J Ritzmann and M Schmidt and H G Babin and R Schott and S R Valentin and S Scholz and Y Wang and R Uppu and D Najer and M C L\"{o}bl and N Tomm and A Javadi and N O Antoniadis and L Midolo and K M\"{u}ller and R J Warburton and P Lodahl and A D Wieck and J J Finley and A Ludwig},

url = {https://doi.org/10.1038/s41467-022-29116-8},

doi = {10.1038/s41467-022-29116-8},

issn = {2041-1723},

year  = {2022},

date = {2022-03-28},

journal = {Nature Communications},

volume = {13},

number = {1},

pages = {1633},

abstract = {Precise control of the properties of semiconductor quantum dots (QDs) is vital for creating novel devices for quantum photonics and advanced opto-electronics. Suitable low QD-densities for single QD devices and experiments are challenging to control during epitaxy and are typically found only in limited regions of the wafer. Here, we demonstrate how conventional molecular beam epitaxy (MBE) can be used to modulate the density of optically active QDs in one- and two- dimensional patterns, while still retaining excellent quality. We find that material thickness gradients during layer-by-layer growth result in surface roughness modulations across the whole wafer. Growth on such templates strongly influences the QD nucleation probability. We obtain density modulations between 1 and 10 QDs/µm2 and periods ranging from several millimeters down to at least a few hundred microns. This method is universal and expected to be applicable to a wide variety of different semiconductor material systems. We apply the method to enable growth of ultra-low noise QDs across an entire 3-inch semiconductor wafer.},

keywords = {Foundry Inorganic},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Band gap and electronic structure of defects in the ternary nitride BP3N6: experiment and theory},

author = {T De Boer and M F A Fattah and M R Amin and S J Ambach and S Vogel and W Schnick and A Moewes},

url = {https://doi.org/10.1039/D1TC06009K},

doi = {10.1039/D1TC06009K},

issn = {2050-7526},

year  = {2022},

date = {2022-03-28},

urldate = {2022-03-28},

journal = {Journal of Materials Chemistry C},

volume = {10},

pages = {6429-6434},

abstract = {Recent advances in methods to access nitride systems by a high-pressure high-temperature approach have made possible the one-step synthesis of mixed ternary non-metal nitrides. As a prerequisite to use in a practical device, it is important to understand important bulk electronic properties, such as the band gap, as well as characterizing the presence and effect of defects that are present. In this work, the novel ternary nitride BP3N6 is studied using techniques sensitive to the partial electronic density of states, specifically X-ray absorption spectroscopy and X-ray emission spectroscopy. Complementary full-potential all-electron density functional theory (DFT) calculations allow important bulk electronic parameters, such as the band gap, to be elucidated. The band gap of BP3N6 has been determined to be 3.9 ± 0.2 eV and 4.1 ± 0.4 eV at the B K- and N K-edges, respectively. This is close to a theoretical value of 4.3 eV predicted by the PBEsol exchange\textendashcorrelation functional and considerably less than a value of 5.8 eV predicted by the modified Becke\textendashJohnson exchange\textendashcorrelation functional. X-Ray excited optical luminescence (XEOL) measurements are performed to interrogate the presence of point defects in this system. Together with DFT calculations, these measurements reveal the presence of nitrogen vacancies which lead to multiple mid-gap trap states.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Self-doping behavior and cation disorder in MgSnN2},

author = {D Han and S S Rudel and W Schnick and H Ebert},

url = {https://link.aps.org/doi/10.1103/PhysRevB.105.125202},

doi = {10.1103/PhysRevB.105.125202},

year  = {2022},

date = {2022-03-28},

journal = {Physical Review B},

volume = {105},

number = {12},

pages = {125202},

abstract = {Investigations on II−Sn−N2(II=Mg, Ca) have been started very recently compared to the intense research of Zn−IV−N2 (IV=Si, Ge, Sn). In this work, we study the phase stability of MgSnN2 and ZnSnN2 in wurtzite and rocksalt phases by first principles calculations. The calculated phase diagram agrees with the experimental observation; i.e., MgSnN2 can form in the wurtzite and rocksalt phases while ZnSnN2 only crystallizes in the wurtzite phase. Due to the higher ionicity of Mg-N bonds compared to Sn-N bonds and Zn-N bonds, wurtzite-type 

MgSnN2 appears under Mg-rich conditions. The defect properties and doping behavior of MgSnN2 in the wurtzite phase are further investigated. We find that MgSnN2 exhibits self-doped n-type conductivity, and donor-type antisite defect SnMg is the primary source of free electrons. The high possibility of forming the stoichiometry-preserving MgSn+SnMg defect complex leads to our study of cation disorder in MgSnN2 by using the cluster expansion method with first principles calculations. It is found that cation disorder in MgSnN2 induces a band-gap reduction because of a violation of the octet rule. The local disorder, namely, forming (4,0) or (0,4) tetrahedra, leads to an appreciable band-gap reduction and hinders the enhancement of the optical absorption.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Process-aid solid engineering triggers delicately modulation of Y-series non-fullerene acceptor for efficient organic solar cells},

author = {X Song and K Zhang and R Guo and K Sun and Z Zhou and S Huang and L Huber and M Reus and J Zhou and M Schwartzkopf and S V Roth and W Liu and Y Liu and W Zhu and P M\"{u}ller-Buschbaum},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adma.202200907},

doi = {https://doi.org/10.1002/adma.202200907},

issn = {0935-9648},

year  = {2022},

date = {2022-03-22},

journal = {Advanced Materials},

volume = {n/a},

number = {n/a},

pages = {2200907},

abstract = {Abstract Volatile solids with symmetric π-backbone have been intensively implemented on manipulating the nanomorphology for improving the operability and stability of organic solar cells. However, due to the isotropic stacking, the announced solids with symmetric geometry cannot modify the microscopic phase separation and component distribution collaboratively, which would constrain the promotion of exciton splitting and charge collection efficiency. Inspired by the superiorities of asymmetric configuration, a novel process-aid solid (PAS) engineering is proposed. By coupling with BTP core unit in Y-series molecule, an asymmetric, volatile 1, 3-dibromo-5-chlorobenzene (DBCl) solid can induce the anisotropic dipole direction, elevated dipole moment, and interlaminar interaction spontaneously. Due to the synergetic effects on the favorable phase separation and desired component distribution, the PAS treated devices feature the evident improvement of exciton splitting, charge transport, and collection, accompanied by the suppressed trap-assisted recombination. Consequently, we achieve an impressive fill factor of 80.2% with maximum power conversion efficiency (PCE) of 18.5% in the PAS treated device. More strikingly, the PAS treated devices demonstrate a promising thickness-tolerance character, where a record PCE of 17.0% is yielded in PAS devices with a 300 nm thickness photoactive layer, which represents the highest PCE for thick-film OSCs. This article is protected by copyright. All rights reserved},

keywords = {Foundry Organic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Scalable, Highly Crystalline, 2D Semiconductor Atomic Layer Deposition Process for High Performance Electronic Applications},

author = {N Aspiotis and K Morgan and B M\"{a}rz and K M\"{u}ller-Caspary and M Ebert and C-C Huang and D W Hewak and S Majumdar and I Zeimpekis},

url = {https://arxiv.org/abs/2203.10309},

doi = {https://doi.org/10.48550/arXiv.2203.10309},

year  = {2022},

date = {2022-03-19},

journal = {arXiv preprint arXiv:2203.10309},

abstract = {This work demonstrates a large area process for atomically thin 2D semiconductors to unlock the technological upscale required for their commercial uptake. The new atomic layer deposition (ALD) and conversion technique yields large area performance uniformity and tunability. Like graphene, 2D Transition Metal Dichalcogenides (TMDCs) are prone to upscaling challenges limiting their commercial uptake. They are challenging to grow uniformly on large substrates and to transfer on alternative substrates while they often lack in large area electrical performance uniformity. The scalable ALD process of this work enables uniform growth of 2D TMDCs on large area with independent control of layer thickness, stoichiometry and crystallinity while allowing chemical free transfers to application substrates. Field effect transistors (FETs) fabricated on flexible substrates using the process present a field effect mobility of up to 55 cm^2/Vs, subthreshold slope down to 80 mV/dec and on/off ratios of 10^7. Additionally, non-volatile memory transistors using ferroelectric FETs (FeFETs) operating at +-5 V with on/off ratio of 107 and a memory window of 3.25 V are demonstrated. These FeFETs demonstrate state-of-the-art performance with multiple state switching, suitable for one-transistor non-volatile memory and for synaptic transistors revealing the applicability of the process to flexible neuromorphic applications.},

keywords = {Foundry Inorganic},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Hydrophobic Graphene Quantum Dots for Defect Passivation and Enhanced Moisture Stability of CH3NH3PbI3 Perovskite Solar Cells},

author = {E Khorshidi and B Rezaei and D Bl\"{a}tte and A Buyruk and M A Reus and J Hanisch and B B\"{o}ller and P M\"{u}ller-Buschbaum and T Ameri},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/solr.202200023},

doi = {https://doi.org/10.1002/solr.202200023},

issn = {2367-198X},

year  = {2022},

date = {2022-03-19},

journal = {Solar RRL},

volume = {n/a},

number = {n/a},

pages = {2200023},

abstract = {Passivating the defects and grain boundaries (GBs) of perovskite films at the interface by interface engineering is a promising route to achieve efficient and stable perovskite solar cells (PSCs). Herein, a new type of graphene, that is, hydrophobic graphene quantum dots (HGQDs) containing amide linkages, which consist of carbonyl and dodecyl amine groups, is successfully used as a bifunctional interface modifier to engineer the interface of the perovskite/hole transport layer. A comprehensive characterization including X-ray photoelectron spectroscopy, Fourier-transform photocurrent spectroscopy, Raman spectroscopy, photoluminescence spectroscopy, and space-charge-limited current measurements is performed to identify the underlying passivation mechanisms. It can be demonstrated that the HGQDs, due to the bifunctional groups containing N and O atoms, effectively passivate the uncoordinated Pb2+ ions at the perovskite film surface and GBs and consequently induce a lower trap state density. Moreover, HGQDs enhance the quality of the perovskite film which reduces the charge recombination at the interface. Therefore, the power conversion efficiency of PSCs treated with HGQDs is significantly increased from 16.00% to 18.30%, mainly based on the improved open-circuit voltage and fill factor. Importantly, the HGQDs featuring hydrophobicity due to alkyl chains significantly enhance moisture stability.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Electron\textendashHole Binding Governs Carrier Transport in Halide Perovskite Nanocrystal Thin Films},

author = {M F Lichtenegger and J Drewniok and A Bornschlegl and C Lampe and A Singldinger and N A Henke and A S Urban},

url = {https://doi.org/10.1021/acsnano.2c00369},

doi = {10.1021/acsnano.2c00369},

issn = {1936-0851},

year  = {2022},

date = {2022-03-18},

journal = {ACS Nano},

abstract = {Two-dimensional halide perovskite nanoplatelets (NPLs) have exceptional light-emitting properties, including wide spectral tunability, ultrafast radiative decays, high quantum yields (QY), and oriented emission. Due to the high binding energies of electron\textendashhole pairs, excitons are generally considered the dominant species responsible for carrier transfer in NPL films. To realize efficient devices, it is imperative to understand how exciton transport progresses therein. We employ spatially and temporally resolved optical microscopy to map exciton diffusion in perovskite nanocrystal (NC) thin films between 15 °C and 55 °C. At room temperature (RT), we find the diffusion length to be inversely correlated to the thickness of the nanocrystals (NCs). With increasing temperatures, exciton diffusion declines for all NC films, but at different rates. This leads to specific temperature turnover points, at which thinner NPLs exhibit higher diffusion lengths. We attribute this anomalous diffusion behavior to the coexistence of excitons and free electron hole-pairs inside the individual NCs within our temperature range. The organic ligand shell surrounding the NCs prevents charge transfer. Accordingly, any time an electron\textendashhole pair spends in the unbound state reduces the FRET-mediated inter-NC transfer rates and, consequently, the overall diffusion. These results clarify how exciton diffusion progresses in strongly confined halide perovskite NC films, emphasizing critical considerations for optoelectronic devices.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Finding efficient catalyst designs: A high-precision method to reveal active sites},

author = {R W Haid and R M Kluge and T O Schmidt and A S Bandarenka},

url = {https://www.sciencedirect.com/science/article/pii/S2667109322001695},

doi = {https://doi.org/10.1016/j.checat.2022.03.024},

issn = {2667-1093},

year  = {2022},

date = {2022-03-16},

journal = {Chem Catalysis},

volume = {2},

number = {4},

pages = {657-659},

abstract = {Designing efficient electrocatalytic structures requires reliable guidelines. For this purpose, experimental approaches for the characterization of model electrodes in operando conditions are valuable. Reporting in Joule, Agnoli et al. showcase the determination of site-specific reaction onset potentials and Tafel slopes by using electrochemical scanning tunneling microscopy.},

keywords = {Solid-Liquid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Anharmonic Lattice Dynamics in Sodium Ion Conductors},

author = {T M Brenner and M Grumet and P Till and M Asher and W G Zeier and D A Egger and O Yaffe},

url = {https://arxiv.org/abs/2203.07955},

doi = {https://doi.org/10.48550/arXiv.2203.07955},

year  = {2022},

date = {2022-03-15},

journal = {arXiv preprint arXiv:2203.07955},

abstract = {We employ THz-range temperature-dependent Raman spectroscopy and first-principles lattice-dynamical calculations to show that the undoped sodium ion conductors Na3PS4 and isostructural Na3PSe4 both exhibit anharmonic lattice dynamics. The anharmonic effects in the compounds involve coupled host lattice -- Na+ ion dynamics that drive the tetragonal-to-cubic phase transition in both cases, but with a qualitative difference in the anharmonic character of the transition. Na3PSe4 shows almost purely displacive character with the soft modes disappearing in the cubic phase as the change of symmetry shifts these modes to the Raman-inactive Brillouin zone boundary. Na3PS4 instead shows order-disorder character in the cubic phase, with the soft modes persisting through the phase transition and remaining active in Raman in the cubic phase, violating Raman selection rules for that phase. Our findings highlight the important role of coupled host lattice -- mobile ion dynamics in vibrational instabilities that are coincident with the exceptional conductivity in these Na+ ion conductors.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Dual In-situ Laser Techniques Underpin the Role of Cations in Impacting Electrocatalysts},

author = {S Hou and L Xu and X Ding and R M Kluge and T K Sarpey and R W Haid and B Garlyyev and S Mukherjee and J Warnan and M Koch and S Zhang and W Li and A S Bandarenka and R A Fischer},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.202201610},

doi = {https://doi.org/10.1002/anie.202201610},

issn = {1433-7851},

year  = {2022},

date = {2022-03-10},

journal = {Angewandte Chemie International Edition},

volume = {n/a},

number = {n/a},

abstract = {Understanding the electrode/electrolyte interface is crucial for optimizing electrocatalytic performances. Here, we demonstrate that the nature of alkali metal cations can profoundly impact the oxygen evolution activity of surface-mounted metal-organic framework (SURMOF) derived electrocatalysts, which are based on NiFe(OOH). In-situ Raman spectroscopy results show that Raman shifts of the Ni-O bending vibration are inversely proportional to the mass activities from Cs+ to Li+. Particularly, a laser-induced current transient technique was introduced to study the cation-dependent electric double layer properties and their effects on the activity. The catalytic trend appeared to be closely related to the potential of maximum entropy of the system, suggesting a strong cation impact on the interfacial water layer structure. Our results highlight how the electrolyte composition can be used to maximize the performance of SURMOF derivatives toward electrochemical water splitting.},

keywords = {Foundry Inorganic, Solid-Liquid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Tuning the feature size of nanoimprinting stamps: A method to enhance the flexibility of nanoimprint lithography},

author = {M Golibrzuch and T L Maier and M J Feil and K Krischer and M Becherer},

url = {https://aip.scitation.org/doi/abs/10.1063/5.0079282},

doi = {10.1063/5.0079282},

year  = {2022},

date = {2022-03-09},

journal = {Journal of Applied Physics},

volume = {131},

number = {12},

pages = {124301},

abstract = {In the field of nanoimprinting lithography, fabricating large-area imprinting stamps is often the most time- and resource-consuming step. Specifically in research, it is often not reasonable to produce a new imprinting stamp for each new experimental configuration. Therefore, the lack of flexibility in feature sizes makes prototyping and tailoring the feature sizes according to their application challenging. To overcome these restrictions, we developed an imprinting stamp reproduction and tuning method which enables the size of the features of existing imprinting stamps to be tuned within nanometer precision. For replication, we first fabricate a chromium nanoisland array on silicon dioxide using the to-be tuned imprinting stamp. Then, the silicon dioxide is anisotropically etched in a reactive ion etching process with chromium as a hard mask. The formed replica of the imprinting stamp is subsequently tuned in an isotropic etching step with hydrofluoric acid. The method enables us to tune the size of the features of our nanoimprinting stamps within nanometer precision without influencing their shape with a yield above 96%. The tuned stamps are then used to fabricate metal nanoisland arrays with the respective tuned sizes. To evaluate the influence of the feature sizes, we exemplarily study the plasmonic resonance of gold nanoisland arrays fabricated using stamps with different feature diameters. Here, we see a good agreement between measured and simulated plasmonic resonance wavelengths of the samples. Hence, with the tuning method, we can tailor specific size-dependent properties of our nanoisland arrays according to individual experiments and applications.},

keywords = {Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Revealing Donor\textendashAcceptor Interaction on the Printed Active Layer Morphology and the Formation Kinetics for Nonfullerene Organic Solar Cells at Ambient Conditions},

author = {X Jiang and P Chotard and K Luo and F Eckmann and S Tu and M A Reus and S Yin and J Reitenbach and C L Weindl and M Schwartzkopf and S V Roth and P M\"{u}ller-Buschbaum},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/aenm.202103977},

doi = {https://doi.org/10.1002/aenm.202103977},

issn = {1614-6832},

year  = {2022},

date = {2022-02-27},

journal = {Advanced Energy Materials},

volume = {n/a},

number = {n/a},

pages = {2103977},

abstract = {Abstract Slot-die coating is a powerful method for upscaling the production of organic solar cells (OSCs) with low energy consumption print processes at ambient conditions. Herein, chlorobenzene (CB) and chloroform (CF) are compared as host solvents for printing films of the neat novel fused-ring unit based wide-bandgap donor polymer (PDTBT2T-FTBDT), the small molecule nonfullerene acceptor based on a fused ring with a benzothiadiazole core (BTP-4F) as well as the respective PDTBT2T-FTBDT:BTP-4F blend films at room temperature in air. Using CF printing of the PDTBT2T-FTBDT:BTP-4F active layer, OSCs with a high power conversion efficiency of up to 13.2% are reached in ambient conditions. In comparison to CB printed blend films, the active layer printed out of CF has a superior morphology, a smoother film surface and a more pronounced face-on orientation of the crystallites, which altogether result in an enhanced exciton dissociation, a superior charge transport, and suppressed nonradiative charge carrier recombination. Based on in situ studies of the slot-die coating process of PDTBT2T-FTBDT, BTP-4F, and PDTBT2T-FTBDT:BTP-4F films, the details of the film formation kinetics are clarified, which cause the superior behavior for CF compared to CB printing due to balancing the aggregation and crystallization of donor and acceptor.},

keywords = {Foundry Organic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Modification of the Electrochemical Surface Oxide Formation and the Hydrogen Oxidation Activity of Ruthenium by Strong Metal Support Interactions},

author = {B M St\"{u}hmeier and R J Schuster and L Hartmann and S Selve and H A El-Sayed and H A Gasteiger },

url = {http://iopscience.iop.org/article/10.1149/1945-7111/ac58c9},

doi = {https://doi.org/10.1149/1945-7111/ac58c9},

issn = {1945-7111},

year  = {2022},

date = {2022-02-25},

urldate = {2022-02-25},

journal = {Journal of The Electrochemical Society},

abstract = {A major hurdle for the wide spread commercialization of proton exchange membrane based fuel cells (PEMFCs) and water electrolyzers are the durability and high cost of noble metal catalysts. Here, alternative support materials might offer advantages, as they can alter the properties of a catalyst by means of a strong metal support interaction (SMSI) that has been shown to prevent platinum oxidation and suppress the oxygen reduction reaction on titanium oxide supported platinum nanoparticles deposited on a carbon support (Pt/TiOx/C). Herein, we report a novel Ru/TiOx/C catalyst that according to tomographic transmission electron microscopy analysis consists of partially encapsulated Ru particles in a Ru/TiOx-composite matrix supported on a carbon support. It is shown by cyclic voltammetry and X-ray photoelectron spectroscopy that ruthenium oxidation is mitigated by an SMSI between Ru and TiOx after reductive heat-treatment (Ru/TiOx/C400°C,H2 ). As a result, the catalyst is capable of oxidizing hydrogen up to the onset of oxygen evolution reaction, in stark contrast to a Ru/C reference catalyst. PEMFC-based hydrogen pump measurements confirmed the stabilization of the hydrogen oxidation reaction (HOR) activity on Ru/TiOx/C400°C,H2 and showed a ≈3 fold higher HOR activity compared to Ru/C, albeit roughly two orders of magnitude less active than Pt/C.},

keywords = {Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Trends in Nanophotonics-Enabled Optofluidic Biosensors},

author = {J Wang and S A Maier and A Tittl},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adom.202102366},

doi = {https://doi.org/10.1002/adom.202102366},

issn = {2195-1071},

year  = {2022},

date = {2022-02-22},

journal = {Advanced Optical Materials},

volume = {n/a},

number = {n/a},

pages = {2102366},

abstract = {Abstract Optofluidic sensors integrate photonics with micro/nanofluidics to realize compact devices for the label-free detection of molecules and the real-time monitoring of dynamic surface binding events with high specificity, ultrahigh sensitivity, low detection limit, and multiplexing capability. Nanophotonic structures composed of metallic and/or dielectric building blocks excel at focusing light into ultrasmall volumes, creating enhanced electromagnetic near-fields ideal for amplifying the molecular signal readout. Furthermore, fluidic control on small length scales enables precise tailoring of the spatial overlap between the electromagnetic hotspots and the analytes, boosting light-matter interaction, and can be utilized to integrate advanced functionalities for the pre-treatment of samples in real-world-use cases, such as purification, separation, or dilution. In this review, the authors highlight current trends in nanophotonics-enabled optofluidic biosensors for applications in the life sciences while providing a detailed perspective on how these approaches can synergistically amplify the optical signal readout and achieve real-time dynamic monitoring, which is crucial in biomedical assays and clinical diagnostics.},

keywords = {Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Multifaceted Role of the Noninnocent Mabiq Ligand in Promoting Selective Reduction of CO2 to CO},

author = {K Rickmeyer and L Niederegger and M Keilwerth and C R Hess},

url = {https://doi.org/10.1021/acscatal.1c04636},

doi = {10.1021/acscatal.1c04636},

year  = {2022},

date = {2022-02-21},

journal = {ACS Catalysis},

pages = {3046-3057},

abstract = {We have investigated the ability of Co\textendash and Fe\textendashMabiq complexes (Mabiq = 2\textendash4:6\textendash8-bis(3,3,4,4-tetramethyldihydropyrrolo)-10-15-(2,2′-biquinazolino)-[15]-1,3,5,8,10,14-hexaene1,3,7,9,11,14-N6) to act as electrocatalysts for CO2 reduction. We observed marked differences in activity when switching the metal center, as the Fe complex outperforms its Co-containing analogue, both in terms of overpotential (η) and faradaic efficiency (FE). [Fe(Mabiq)2(MeCN)2]PF6 ([2]+) selectively reduces CO2 to CO with an overpotential requirement of 500 mV. We have synthesized and fully characterized the two-electron reduced Na(OEt2)[Fe(Mabiq)] ([2]\textendash), which consists of an intermediate spin FeII center coupled to a ligand biradical and exhibits a unique S = 1 spin state. Both electrochemical and reactivity studies with [2]\textendash point toward a protonated precatalytic intermediate (IPhOH). The molecular structure of IPhOH indicates the diketiminate carbon as the site of protonation and the ability of the Mabiq ligand to engage in hydrogen bonding interactions. The noninnocent Mabiq ligand, therefore, acts not only as an electron reservoir but also as a proton storage site. Our ligand system uniquely combines two beneficial features, a redox-active unit and a proton donor site, that in combination with the metal ion reduces overpotentials and facilitates selective CO2 conversion.},

keywords = {Foundry Inorganic},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Discovery of Two Polymorphs of TiP4N8 Synthesized from Binary Nitrides},

author = {L Eisenburger and V Weippert and C Paulmann and D Johrendt and O Oeckler and W Schnick},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.202202014},

doi = {https://doi.org/10.1002/anie.202202014},

issn = {1433-7851},

year  = {2022},

date = {2022-02-18},

journal = {Angewandte Chemie International Edition},

volume = {n/a},

number = {n/a},

pages = {e202202014},

abstract = {Abstract TiP4N8 was obtained from the binary nitrides TiN and P3N5 upon addition of NH4F as a mineralizer at 8 GPa and 1400 °C. An intricate interplay of disorder and polymorphism was elucidated by in situ temperature-dependent single-crystal X-ray diffraction, STEM-HAADF, and the investigation of annealed samples. This revealed two polymorphs, which consist of dense networks of PN4 tetrahedra (degree of condensation κ=0.5) and either augmented triangular TiN7 prisms or triangular TiN6 prisms for α- and β-TiP4N8, respectively. The structures of TiP4N8 exhibit body-centered tetragonal (bct) framework topology. DFT calculations confirm the measured band gaps of α- and β-TiP4N8 (1.6\textendash1.8 eV) and predict the thermochemistry of the polymorphs in agreement with the experiments.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Low-Temperature and Water-Based Biotemplating of Nanostructured Foam-Like Titania Films Using \ss-Lactoglobulin},

author = {J E Heger and W Chen and S Yin and N Li and V K\"{o}rstgens and C J Brett and W Ohm and S V Roth and P M\"{u}ller-Buschbaum},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adfm.202113080},

doi = {https://doi.org/10.1002/adfm.202113080},

issn = {1616-301X},

year  = {2022},

date = {2022-02-17},

journal = {Advanced Functional Materials},

volume = {n/a},

number = {n/a},

pages = {2113080},

abstract = {Abstract Given the broad use of nanostructured crystalline titania films, an environmentally friendly and more sustainable synthesis route is highly desirable. Here, a water-based, low-temperature route is presented to synthesize nanostructured foam-like crystalline titania films. A pearl necklace-like nanostructure is introduced as tailored titania morphology via biotemplating with the use of the major bovine whey protein \ss-lactoglobulin (\ss-lg). It is shown that titania crystallization in a brookite-anatase mixed phase is promoted via spray deposition at a comparatively low temperature of 120 °C. The obtained crystallites have an average grain size of (4.2 ± 0.3) nm. In situ grazing incidence small-angle and wide-angle X-ray scattering (GISAXS/GIWAXS) are simultaneously performed to understand the kinetics of film formation and the templating role of \ss-lg during spray coating. In the \ss-lg:titania biohybrid composites, the crystal growth in semicrystalline titania clusters is sterically directed by the condensing \ss-lg biomatrix. Due to using spray coating, the green chemistry approach to titania-based functional films can be scaled up on a large scale, which can potentially be used in photocatalytic processes or systems related to energy application.},

keywords = {Foundry Inorganic, Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Direct and Linker-Exchange Alcohol-Assisted Hydrothermal Synthesis of Imide-Linked Covalent Organic Frameworks},

author = {J Maschita and T Banerjee and B V Lotsch},

url = {https://doi.org/10.1021/acs.chemmater.1c04051},

doi = {10.1021/acs.chemmater.1c04051},

issn = {0897-4756},

year  = {2022},

date = {2022-02-17},

journal = {Chemistry of Materials},

abstract = {Covalent organic frameworks (COFs) are an extensively studied class of porous materials, which distinguish themselves from other porous polymers in their crystallinity and high degree of modularity, enabling a wide range of applications. However, the established synthetic protocols for the synthesis of stable and crystalline COFs, such as imide-linked COFs, often requires the use of high boiling solvents and toxic catalysts, making their synthesis expensive and environmentally harmful. Herein, we report a new environmentally friendly strategy─an alcohol-assisted hydrothermal polymerization approach (aaHTP) for the synthesis of a wide range of crystalline and porous imide-linked COFs. This method allows us to gain access to new COFs and to avoid toxic solvents by up to 90% through substituting commonly used organic solvent mixtures with water and small amounts of n-alcohols without being restricted to water-soluble linker molecules. Additionally, we use the aaHTP to demonstrate an eco-friendly COF-to-COF transformation of an imine-linked COF into a novel imide-linked COF via linkage replacement, inaccessible using published reaction conditions.},

keywords = {Foundry Organic},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Ultrafast sub-100 fs all-optical modulation and efficient third-harmonic generation in Weyl semimetal niobium phosphide thin films},

author = {B Tilmann and A K Pandeya and G Grinblat and L D S Menezes and Y Li and C Shekhar and C Felser and S S P Parkin and A Bedoya-Pinto and S A Maier},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adma.202106733},

doi = {https://doi.org/10.1002/adma.202106733},

issn = {0935-9648},

year  = {2022},

date = {2022-02-16},

journal = {Advanced Materials},

volume = {n/a},

number = {n/a},

pages = {2106733},

abstract = {Abstract Since their experimental discovery in 2015, Weyl semimetals generated a large amount of attention due their intriguing physical properties that arise from their linear electron dispersion relation and topological surface states. In particular in the field of nonlinear (NL) optics and light harvesting, Weyl semimetals have shown outstanding performances and achieved record NL conversion coefficients. In this context, we perform first steps towards Weyl semimetal nanophotonics by thoroughly characterizing the linear and NL optical behavior of epitaxially grown niobium phosphide (NbP) thin films, covering the visible to near-infrared regime of the electromagnetic spectrum. Despite the measured high linear absorption, third-harmonic generation studies demonstrate high conversion efficiencies up to 10-4%, that can be attributed to the topological electron states at the surface of the material. Furthermore, nondegenerate pump-probe measurements with sub-10 fs pulses reveal a maximum modulation depth of about 1%, completely decaying within 100 fs and therefore suggesting the possibility of developing devices based on NbP with all-optical switching bandwidths of up to 10 THz. Altogether, our work reveals promising NL optical properties of Weyl semimetal thin films that are outperforming bulk crystals of the same material, laying the grounds for nanoscale applications, enabled by top-down nanostructuring, such as light-harvesting, on-chip frequency conversion and all-optical processing. This article is protected by copyright. All rights reserved},

keywords = {Foundry Inorganic},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Vertical Cu Nanoneedle Arrays Enhance the Local Electric Field Promoting C2 Hydrocarbons in the CO2 Electroreduction},

author = {Y Zhou and Y Liang and J Fu and K Liu and Q Chen and X Wang and H Li and L Zhu and J Hu and H Pan and M Miyauchi and L Jiang and E Cort\'{e}s and M Liu},

url = {https://doi.org/10.1021/acs.nanolett.1c04653},

doi = {10.1021/acs.nanolett.1c04653},

issn = {1530-6984},

year  = {2022},

date = {2022-02-15},

journal = {Nano Letters},

abstract = {Electrocatalytic reduction of CO2 to multicarbon products is a potential strategy to solve the energy crisis while achieving carbon neutrality. To improve the efficiency of multicarbon products in Cu-based catalysts, optimizing the *CO adsorption and reducing the energy barrier for carbon\textendashcarbon (C\textendashC) coupling are essential features. In this work, a strong local electric field is obtained by regulating the arrangement of Cu nanoneedle arrays (CuNNAs). CO2 reduction performance tests indicate that an ordered nanoneedle array reaches a 59% Faraday efficiency for multicarbon products (FEC2) at −1.2 V (vs RHE), compared to a FEC2 of 20% for a disordered nanoneedle array (CuNNs). As such, the very high and local electric fields achieved by an ordered Cu nanoneedle array leads to the accumulation of K+ ions, which benefit both *CO adsorption and C\textendashC coupling. Our results contribute to the design of highly efficient catalysts for multicarbon products.},

keywords = {Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Solvent Tuning of the Active Layer Morphology of Non-Fullerene Based Organic Solar Cells},

author = {S Grott and A Kotobi and L K Reb and C L Weindl and R Guo and S Yin and K S Wienhold and W Chen and T Ameri and M Schwartzkopf and S V Roth and P M\"{u}ller-Buschbaum},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/solr.202101084},

doi = {https://doi.org/10.1002/solr.202101084},

issn = {2367-198X},

year  = {2022},

date = {2022-02-12},

journal = {Solar RRL},

volume = {n/a},

number = {n/a},

pages = {2101084},

abstract = {Non-fullerene acceptor (NFA)-based organic solar cells have made tremendous progress in recent years. For the neat NFA system PBDB-T:ITIC, the film morphology and crystallinity are tailored by the choice of the solvent used for spin coating the active layers. Three different chlorinated solvents, chlorobenzene (CB), chloroform, and dichlorobenzene, are compared and the obtained active layer morphology is correlated with the optoelectronic properties and the device performance. The small domain sizes in the case of CB are most beneficial for the device performance, whereas the largest number or size of face-on PBDB-T crystallites is not causing the highest power conversion efficiencies (PCEs). In addition, when using CB, the number of edge-on crystallites is highest and the distances between neighboring domains are small. The smoothest blend films are realized with CB, which exhibit correlated roughness with their substrates and no large aggregates have formed in these blend films. Thus, CB offers the best way to balance the aggregation and crystallization kinetics in the active layer and enables the highest PCE values.},

keywords = {Foundry Organic, Solid-Liquid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Halide\textendashMetal Complexes at Plasmonic Interfaces Create New Decay Pathways for Plasmons and Excited Molecules},

author = {A Stefancu and O M Biro and O Todor-Boer and I Botiz and E Cort\'{e}s and N Leopold},

url = {https://doi.org/10.1021/acsphotonics.1c01714},

doi = {10.1021/acsphotonics.1c01714},

year  = {2022},

date = {2022-02-10},

journal = {ACS Photonics},

abstract = {We show that by modifying the chemical interface of silver nanoparticles (AgNPs) with halide ions, it is possible to tune the total decay rate of adsorbed excited molecules and the plasmon damping rate. Through single-molecule surface-enhanced Raman scattering and surface-enhanced fluorescence enhancement factors of crystal violet (CV) and rhodamine 6G (R6G), we show that I\textendash-modified AgNPs (AgNPs@I) and Br\textendash-modified AgNPs (AgNPs@Br) lead to an increase in the total decay rate of excited CV and R6G by a factor between ∼1.6\textendash2.6, compared to Cl\textendash-modified AgNPs (AgNPs@Cl). In addition, we found that the chemical interface damping, which characterizes the plasmon resonance decay into surface states, is stronger on AgNPs@I and AgNPs@Br when compared to AgNPs@Cl. These results point toward the formation of metal\textendashhalide surface complexes. These new interfacial states can accept electrons from both excited molecular orbitals and surface plasmon excitations, completely altering the electronic dynamics and reactivity of plasmonic interfaces.},

keywords = {Foundry Inorganic, Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Accelerating CO2 Electroreduction to Multicarbon Products via Synergistic Electric\textendashThermal Field on Copper Nanoneedles},

author = {B Yang and K Liu and H Li and C Liu and J Fu and H Li and J E Huang and P Ou and T Alkayyali and C Cai and Y Duan and H Liu and P An and N Zhang and W Li and X Qiu and C Jia and J Hu and L Chai and Z Lin and Y Gao and M Miyauchi and E Cort\'{e}s and S A Maier and M Liu},

url = {https://doi.org/10.1021/jacs.1c11253},

doi = {10.1021/jacs.1c11253},

issn = {0002-7863},

year  = {2022},

date = {2022-02-03},

urldate = {2022-02-03},

journal = {Journal of the American Chemical Society},

abstract = {Electrochemical CO2 reduction is a promising way to mitigate CO2 emissions and close the anthropogenic carbon cycle. Among products from CO2RR, multicarbon chemicals, such as ethylene and ethanol with high energy density, are more valuable. However, the selectivity and reaction rate of C2 production are unsatisfactory due to the sluggish thermodynamics and kinetics of C\textendashC coupling. The electric field and thermal field have been studied and utilized to promote catalytic reactions, as they can regulate the thermodynamic and kinetic barriers of reactions. Either raising the potential or heating the electrolyte can enhance C\textendashC coupling, but these come at the cost of increasing side reactions, such as the hydrogen evolution reaction. Here, we present a generic strategy to enhance the local electric field and temperature simultaneously and dramatically improve the electric\textendashthermal synergy desired in electrocatalysis. A conformal coating of ∼5 nm of polytetrafluoroethylene significantly improves the catalytic ability of copper nanoneedles (∼7-fold electric field and ∼40 K temperature enhancement at the tips compared with bare copper nanoneedles experimentally), resulting in an improved C2 Faradaic efficiency of over 86% at a partial current density of more than 250 mA cm\textendash2 and a record-high C2 turnover frequency of 11.5 ± 0.3 s\textendash1 Cu site\textendash1. Combined with its low cost and scalability, the electric\textendashthermal strategy for a state-of-the-art catalyst not only offers new insight into improving activity and selectivity of value-added C2 products as we demonstrated but also inspires advances in efficiency and/or selectivity of other valuable electro-/photocatalysis such as hydrogen evolution, nitrogen reduction, and hydrogen peroxide electrosynthesis.},

keywords = {Foundry Inorganic, Solid-Liquid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Correlated spectral fluctuations quantified by line shape analysis of fifth-order two-dimensional electronic spectra},

author = {C Heshmatpour and J Hauer and F \v{S}anda},

url = {https://aip.scitation.org/doi/abs/10.1063/5.0081053},

doi = {10.1063/5.0081053},

year  = {2022},

date = {2022-02-01},

journal = {The Journal of Chemical Physics},

volume = {156},

number = {8},

pages = {084114},

abstract = {Correlated spectral fluctuations were suggested to coordinate excitation transport inside natural light harvesting complexes. We demonstrate the capacities of 2D line shapes from fifth-order coherent electronic signals (R5-2D) to report on such fluctuations in molecular aggregates and present a stochastic approach to fluctuations in correlated site and bi-exciton binding energies in the optical dynamics of Frenkel excitons. The model is applied to R5-2D line shapes of a homodimer, and we show that the peak tilt dynamics are a measure for site energy disorder, inter-site correlation, and the strength of bi-exciton binding energy fluctuations.},

keywords = {Foundry Inorganic},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {All About the Interface: Do Residual Contaminants at A High-Quality h-BN Monolayer Perylene Diimide Interface Cause Charge Trapping?},

author = {L Renn and L S Walter and K Watanabe and T Taniguchi and R T Weitz},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/admi.202101701},

doi = {https://doi.org/10.1002/admi.202101701},

issn = {2196-7350},

year  = {2022},

date = {2022-01-29},

journal = {Advanced Materials Interfaces},

volume = {n/a},

number = {n/a},

pages = {2101701},

abstract = {Abstract Intrinsic charge transport in molecularly thin organic semiconducting crystals is critically sensitive to the quality of the interfaces required to perform the electrical measurements. Most prominent are the dielectric\textendashsemiconductor and semiconductor\textendashmetal interface. While impacts from the latter on charge transport can be extracted by four-terminal measurements, the impact of the dielectric interface can only be minimized, typically by utilizing inert dielectrics. Here, it is shown that charge transport in organic field-effect transistors based on the n-type small molecule N, N′-di((S)-1-methylpentyl)-1,7(6)-dicyano-perylene-3,4:9,10-bis(dicarboximide) (PDI1MPCN2) can be improved up to one order of magnitude by using hexagonal boron nitride (h-BN) as dielectric, compared to a standard SiO2 substrate. Using temperature-dependent electrical measurements, the charge-transport properties of devices are systematically analyzed, and high four-terminal mobilities of up to 5.0 cm2 V−1 s−1 are obtained. The high mobility likely stems from decreased charge-carrier trapping at the semiconductor-dielectric interface due to the smooth surface of the inert h-BN. Nevertheless, the temperature dependencies of the mobility, threshold voltage, and interface-state trap density suggest that charge-carrier trapping at the dielectric-semiconductor interface still exists. By comparing the data to transport studies performed on thin air-gapped organic films, it is concluded that an interfacial layer (likely water or solvent residues) between h-BN and the monolayer PDI1MPCN2 causes charge trapping.},

keywords = {Foundry Organic},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Single-photon emitters in layered van der Waals materials},

author = {S Michaelis De Vasconcellos and D Wigger and U Wurstbauer and A W Holleitner and R Bratschitsch and T Kuhn},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/pssb.202100566},

doi = {https://doi.org/10.1002/pssb.202100566},

issn = {0370-1972},

year  = {2022},

date = {2022-01-28},

journal = {physica status solidi (b)},

volume = {n/a},

number = {n/a},

abstract = {Single-photon emitters have recently been discovered in various atomically thin materials. Their properties, controllability, and the possibility of their monolithic integration in electronic and photonic device structures makes them attractive candidates for a wide range of applications in quantum information and communication, and also in other fields of physics and technology. In this review article an overview of single-photon emitters in layered van der Waals materials and their physical properties is given, theoretical concepts for the modeling of their level structure and their coupling to phonons are presented, and techniques for the creation and localization of these emitters in the host material are described. Perspectives for their application in various fields, such as their coupling to photonic resonators and waveguides, their control by external electric fields or strain, and their integration in optomechanical devices are discussed. Finally, functionalities relying on properties beyond single-photon emission are briefly addressed. This article is protected by copyright. All rights reserved.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Quantitative Single-Molecule Measurements of Membrane Charges with DNA Origami Sensors},

author = {S E Ochmann and T Schr\"{o}der and C M Schulz and P Tinnefeld},

url = {https://doi.org/10.1021/acs.analchem.1c05092},

doi = {10.1021/acs.analchem.1c05092},

issn = {0003-2700},

year  = {2022},

date = {2022-01-28},

journal = {Analytical Chemistry},

abstract = {Charges in lipid head groups generate electrical surface potentials at cell membranes, and changes in their composition are involved in various signaling pathways, such as T-cell activation or apoptosis. Here, we present a DNA origami-based sensor for membrane surface charges with a quantitative fluorescence read-out of single molecules. A DNA origami plate is equipped with modifications for specific membrane targeting, surface immobilization, and an anionic sensing unit consisting of single-stranded DNA and the dye ATTO542. This unit is anchored to a lipid membrane by the dye ATTO647N, and conformational changes of the sensing unit in response to surface charges are read out by fluorescence resonance energy transfer between the two dyes. We test the performance of our sensor with single-molecule fluorescence microscopy by exposing it to differently charged large unilamellar vesicles. We achieve a change in energy transfer of ∼10% points between uncharged and highly charged membranes and demonstrate a quantitative relation between the surface charge and the energy transfer. Further, with autocorrelation analyses of confocal data, we unravel the working principle of our sensor that is switching dynamically between a membrane-bound state and an unbound state on the timescale of 1\textendash10 ms. Our study introduces a complementary sensing system for membrane surface charges to previously published genetically encoded sensors. Additionally, the single-molecule read-out enables investigations of lipid membranes on the nanoscale with a high spatial resolution circumventing ensemble averaging.},

keywords = {Foundry Organic, Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Robust excitons across the phase transition of two-dimensional hybrid perovskites},

author = {J D Ziegler and K-Q Lin and B Meisinger and X Zhu and M Kober-Czerny and P K Nayak and C Vona and T Taniguchi and K Watanabe and C Draxl},

url = {https://arxiv.org/abs/2201.11589},

doi = {arXiv:2201.11589v1},

year  = {2022},

date = {2022-01-27},

journal = {arXiv preprint arXiv:2201.11589},

abstract = {Two-dimensional halide perovskites are among intensely studied materials platforms profiting from solution based growth and chemical flexibility. They feature exceptionally strong interactions among electronic, optical as well as vibrational excitations and hold a great potential for future optoelectronic applications. A key feature for these materials is the occurrence of structural phase transitions that can impact their functional properties, including the electronic band gap and optical response dominated by excitons. However, to what extent the phase-transitions in two-dimensional perovskites alter the fundamental exciton properties remains barely explored so far. Here, we study the influence of the phase transition on both exciton binding energy and exciton diffusion, demonstrating their robust nature across the phase transition. These findings are unexpected in view of the associated substantial changes of the free carrier masses, strongly contrast broadly considered effective mass and drift-diffusion transport mechanisms, highlighting the unusual nature of excitons in two-dimensional perovskites.},

keywords = {Foundry Inorganic},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Surface NMR using quantum sensors in diamond},

author = {K S Liu and A Henning and M W Heindl and R D Allert and J D Bartl and I D Sharp and R Rizzato and D B Bucher},

url = {https://www.pnas.org/doi/abs/10.1073/pnas.2111607119 %X Many of the functions and applications of materials in catalysis, energy conversion, drug delivery, bioanalysis, and electronics are based on their interfacial properties and structures. The characterization of their molecular properties under ambient or chemically reactive conditions is a fundamental scientific challenge. Here, we develop a surface-sensitive magnetic resonance technique that combines the nanoscale-sensing capabilities of defects in diamond with a high precision and versatile protocol for diamond surface modification. We demonstrate the functionality of this method for probing the molecular properties and kinetics at surfaces and interfaces under ambient conditions. NMR is a noninvasive, molecular-level spectroscopic technique widely used for chemical characterization. However, it lacks the sensitivity to probe the small number of spins at surfaces and interfaces. Here, we use nitrogen vacancy (NV) centers in diamond as quantum sensors to optically detect NMR signals from chemically modified thin films. To demonstrate the method’s capabilities, aluminum oxide layers, common supports in catalysis and materials science, are prepared by atomic layer deposition and are subsequently functionalized by phosphonate chemistry to form self-assembled monolayers. The surface NV-NMR technique detects spatially resolved NMR signals from the monolayer, indicates chemical binding, and quantifies molecular coverage. In addition, it can monitor in real time the formation kinetics at the solid\textendashliquid interface. With our approach, we show that NV quantum sensors are a surface-sensitive NMR tool with femtomole sensitivity for in situ analysis in catalysis, materials, and biological research.},

doi = {doi:10.1073/pnas.2111607119},

year  = {2022},

date = {2022-01-26},

journal = {Proceedings of the National Academy of Sciences},

volume = {119},

number = {5},

pages = {e2111607119},

abstract = {NMR is a noninvasive, molecular-level spectroscopic technique widely used for chemical characterization. However, it lacks the sensitivity to probe the small number of spins at surfaces and interfaces. Here, we use nitrogen vacancy (NV) centers in diamond as quantum sensors to optically detect NMR signals from chemically modified thin films. To demonstrate the method’s capabilities, aluminum oxide layers, common supports in catalysis and materials science, are prepared by atomic layer deposition and are subsequently functionalized by phosphonate chemistry to form self-assembled monolayers. The surface NV-NMR technique detects spatially resolved NMR signals from the monolayer, indicates chemical binding, and quantifies molecular coverage. In addition, it can monitor in real time the formation kinetics at the solid\textendashliquid interface. With our approach, we show that NV quantum sensors are a surface-sensitive NMR tool with femtomole sensitivity for in situ analysis in catalysis, materials, and biological research.},

keywords = {Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Depositing Molecular Graphene Nanoribbons on Ag(111) by Electrospray - Controlled Ion Beam Deposition: Self-assembly and On-Surface Transformations},

author = {W Ran and A Walz and K Stoiber and P Knecht and H Xu and A C Papageorgiou and A Huettig and D Cortizo-Lacalle and J P Mora-Fuentes and A Mateo-Alonso and H Schlichting and J Reichert and J V Barth},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.202111816},

doi = {https://doi.org/10.1002/anie.202111816},

issn = {1433-7851},

year  = {2022},

date = {2022-01-25},

journal = {Angewandte Chemie International Edition},

volume = {n/a},

number = {n/a},

abstract = {The chemical processing of low dimensional carbon nanostructures is crucial for their integration in future devices. Here we apply a new methodology in atomically precise engineering by combining multistep solution synthesis of N-doped molecular graphene nanoribbons (GNRs) with mass-selected ultra-high vacuum electrospray - controlled ion beam deposition on surfaces and real space visualisation by scanning tunnelling microscopy. We demonstrate how this method yields solely a controllable amount of single, otherwise unsublimable, GNRs of 2.9 nm length on a planar Ag(111) surface. This methodology allows for further processing by employing on-surface synthesis protocols and exploiting the reactivity of the substrate. Following multiple chemical transformations, the GNRs provide reactive building blocks to form extended, metal-organic coordination polymers.},

keywords = {Solid-Solid},

pubstate = {published},

tppubtype = {article}

}