Publications

@article{nokey,

title = {MXene-induced nonradiative energy transfer},

author = {C L M Palenzuela and D Spurling and A Szalai and T Schr\"{o}der and V Nicolosi and P Tinnefeld},

url = {https://chemrxiv.org/engage/chemrxiv/article-details/6544ea8948dad23120fe8d2a},

doi = {10.26434/chemrxiv-2023-r54g8},

abstract = {Since their discovery in 2011, MXenes have risen to prominence for energy storage, electromagnetic shielding, and optoelectronics. Yet, the nonradiative energy transfer properties of this family of 2D materials remain elusive, which may have implications in optoelectronics, photovoltaics and biosensing. Here, we use single-molecule fluorescence confocal microscopy and DNA origami nanopositioners to investigate, for the first time, the distance-dependent energy transfer of an organic emitter (ATTO 542) placed on transparent thin films made of spincast Ti3C2Tx flakes. We propose a specific immobilization chemistry for DNA origami nanostructures based on glycine-MXene interaction, allowing us to precisely control their orientation on the surface. Each DNA origami structure is designed to carry a single dye molecule at predetermined heights. Our findings reveal that when the dye is located at distances of 1 nm \< d \< 8 nm from the surface, the fluorescence is quenched following a distance dependence of d-3. This is in agreement with the F\"{o}rster-type mechanism of energy transfer in transparent conductors at the bulk level. 50% of energy transfer efficiency is reached at 2.7 nm (d0). MXenes could therefore be used as short-distance spectroscopic nanorulers, sensitive at a distance regime that common energy transfer tools cannot access.},

keywords = {Foundry Organic, Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Diamond photonic crystals assembled from DNA origami},

author = {G Posnjak and X Yin and P Butler and O Bienek and M Dass and I D Sharp and T Liedl},

url = {https://arxiv.org/abs/2310.10884},

doi = {https://doi.org/10.48550/arXiv.2310.10884},

journal = {arXiv preprint arXiv:2310.10884},

abstract = {Colloidal self-assembly allows rational design of structures on the micron and submicron scale, potentially leading to physical material properties that are rare or non-existent in nature. One of the architectures that can generate complete 3D photonic band gaps is the diamond cubic lattice, which has remained difficult to realize at length scales comparable to the wavelength of visible light. Here, we demonstrate 3D photonic crystals self-assembled from DNA origami that act as precisely programmable patchy colloids. Our DNA-based nanoscale tetrapods crystallize into a rod-connected diamond cubic lattice with a periodicity of 170 nm that serves as a scaffold for atomic layer deposition of high refractive index materials such as TiO2, yielding a tunable photonic band gap in the near UV range.},

keywords = {Foundry Organic, Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Exploring the Synergies of Single-Molecule Fluorescence and 2D Materials Coupled by DNA},

author = {L Richter and A M Szalai and C L Manzanares-Palenzuela and I Kami\'{n}ska and P Tinnefeld},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adma.202303152},

doi = {https://doi.org/10.1002/adma.202303152},

issn = {0935-9648},

journal = {Advanced Materials},

volume = {35},

number = {41},

pages = {2303152},

abstract = {Abstract The world of 2D materials is steadily growing, with numerous researchers attempting to discover, elucidate, and exploit their properties. Approaches relying on the detection of single fluorescent molecules offer a set of advantages, for instance, high sensitivity and specificity, that allow the drawing of conclusions with unprecedented precision. Herein, it is argued how the study of 2D materials benefits from fluorescence-based single-molecule modalities, and vice versa. A special focus is placed on DNA, serving as a versatile adaptor when anchoring single dye molecules to 2D materials. The existing literature on the fruitful combination of the two fields is reviewed, and an outlook on the additional synergies that can be created between them provided.},

keywords = {Foundry Organic, Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Fast optoelectronic charge state conversion of silicon vacancies in diamond},

author = {M Rieger and V Villafane and L M Todenhagen and S Matthies and S Appel and M S Brandt and K Mueller and J J Finley},

url = {https://arxiv.org/abs/2310.12288},

doi = {https://doi.org/10.48550/arXiv.2310.12288},

journal = {arXiv preprint arXiv:2310.12288},

abstract = {Group IV vacancy color centers in diamond are promising spin-photon interfaces with strong potential for applications for photonic quantum technologies. Reliable methods for controlling and stabilizing their charge state are urgently needed for scaling to multi-qubit devices. Here, we manipulate the charge state of silicon vacancy (SiV) ensembles by combining luminescence and photo-current spectroscopy. We controllably convert the charge state between the optically active SiV− and dark SiV2− with MHz rates and 90% contrast by judiciously choosing the local potential applied to in-plane surface electrodes and the laser excitation wavelength. We observe intense SiV− photoluminescence under hole-capture, measure the intrinsic conversion time from the dark SiV2− to the bright SiV− to be 36.4(6.7)ms and demonstrate how it can be enhanced by a factor of 105 via optical pumping. Moreover, we obtain new information on the defects that contribute to photo-conductivity, indicating the presence of substitutional nitrogen and divacancies.},

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

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Extending the coherence of spin defects in hBN enables advanced qubit control and quantum sensing},

author = {R Rizzato and M Schalk and S Mohr and J C Hermann and J P Leibold and F Bruckmaier and G Salvitti and C Qian and P Ji and G V Astakhov and U Kentsch and M Helm and A V Stier and J J Finley and D B Bucher},

url = {https://doi.org/10.1038/s41467-023-40473-w},

doi = {10.1038/s41467-023-40473-w},

issn = {2041-1723},

journal = {Nature Communications},

volume = {14},

number = {1},

pages = {5089},

abstract = {Negatively-charged boron vacancy centers ($$V_B^-$$) in hexagonal Boron Nitride (hBN) are attracting increasing interest since they represent optically-addressable qubits in a van der Waals material. In particular, these spin defects have shown promise as sensors for temperature, pressure, and static magnetic fields. However, their short spin coherence time limits their scope for quantum technology. Here, we apply dynamical decoupling techniques to suppress magnetic noise and extend the spin coherence time by two orders of magnitude, approaching the fundamental T1 relaxation limit. Based on this improvement, we demonstrate advanced spin control and a set of quantum sensing protocols to detect radiofrequency signals with sub-Hz resolution. The corresponding sensitivity is benchmarked against that of state-of-the-art NV-diamond quantum sensors. This work lays the foundation for nanoscale sensing using spin defects in an exfoliable material and opens a promising path to quantum sensors and quantum networks integrated into ultra-thin structures.},

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

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Hot Electron Dynamics in InAs\textendashAlAsSb Core\textendashShell Nanowires},

author = {D Sandner and H Esmaielpour and F D Giudice and S Meder and M Nuber and R Kienberger and G Koblm\"{u}ller and H Iglev},

url = {https://doi.org/10.1021/acsaem.3c01565},

doi = {10.1021/acsaem.3c01565},

journal = {ACS Applied Energy Materials},

volume = {6},

number = {20},

pages = {10467-10474},

abstract = {Semiconductor nanowires (NWs) have shown evidence of robust hot-carrier effects due to their small dimensions, making them attractive for advanced photoenergy conversion concepts. Especially, indium arsenide (InAs) NWs are promising candidates for harvesting hot carriers due to their high absorption coefficient, high carrier mobility, and large effective electron-to-hole mass difference. Here, we investigate the cooling and recombination dynamics of photoexcited hot carriers in pure and passivated InAs NWs by using ultrafast near-infrared pump\textendashprobe spectroscopy. We observe reduced Auger recombination in pure InAs NWs compared to that in passivated ones and associate this with charge-carrier separation by surface band bending. Similarly, faster carrier cooling by electron\textendashhole scattering is observed in passivated InAs\textendashAlAsSb NWs at high carrier densities in excess of 1018 cm\textendash3, where hot electron lifetimes in this regime increase substantially with the pump fluence due to Auger heating. These results emphasize the importance of type-II alignment for charge-carrier separation in hot-carrier devices to suppress carrier-mediated cooling channels. In addition, a separate charge-carrier population lasting up to several nanoseconds is observed for photoexcitation of the NW shell. Despite the high conduction band offset, carrier migration is not observed in the range of 40 ps to 2 ns. This observation may open avenues for core\textendashshell NW multijunction solar cells.},

keywords = {Foundry Inorganic, Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Accessible hotspots for single-protein SERS in DNA-origami assembled gold nanorod dimers with tip-to-tip alignment},

author = {F Schuknecht and K Ko\l\k{a}taj and M Steinberger and T Liedl and T Lohmueller},

url = {https://doi.org/10.1038/s41467-023-42943-7},

doi = {10.1038/s41467-023-42943-7},

issn = {2041-1723},

journal = {Nature Communications},

volume = {14},

number = {1},

pages = {7192},

abstract = {The label-free identification of individual proteins from liquid samples by surface-enhanced Raman scattering (SERS) spectroscopy is a highly desirable goal in biomedical diagnostics. However, the small Raman scattering cross-section of most (bio-)molecules requires a means to strongly amplify their Raman signal for successful measurement, especially for single molecules. This amplification can be achieved in a plasmonic hotspot that forms between two adjacent gold nanospheres. However, the small (≈1−2 nm) gaps typically required for single-molecule measurements are not accessible for most proteins. A useful strategy would thus involve dimer structures with gaps large enough to accommodate single proteins, whilst providing sufficient field enhancement for single-molecule SERS. Here, we report on using a DNA origami scaffold for tip-to-tip alignment of gold nanorods with an average gap size of 8 nm. The gaps are accessible to streptavidin and thrombin, which are captured at the plasmonic hotspot by specific anchoring sites on the origami template. The field enhancement achieved for the nanorod dimers is sufficient for single-protein SERS spectroscopy with sub-second integration times. This design for SERS probes composed of DNA origami with accessible hotspots promotes future use for single-molecule biodiagnostics in the near-infrared range.},

keywords = {Foundry Organic, Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {In-situ study of degradation in PTB7:PCBM films prepared with the binary solvent additive DPE:DIO},

author = {D M Schwaiger and W Lohstroh and M Wolf and C J Garvey and P M\"{u}ller-Buschbaum},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/pol.20230072},

doi = {https://doi.org/10.1002/pol.20230072},

issn = {2642-4150},

journal = {Journal of Polymer Science},

volume = {61},

number = {15},

pages = {1660-1674},

abstract = {Abstract Blend films of poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl]] (PTB7) in combination with 6,6-phenyl-C61-butyric-acid-methyl-ester (PCBM) are a model system for low bandgap organic photovoltaics. Typically, solvent additives are used to improve the power conversion efficiencies of the resulting devices but possibly also decrease the device stability. In this study, we use the binary solvent additive 1,8-diiodooctane:diphenylether (DIO:DPE) for PTB7:PCBM blend films and study how different film drying procedures influence the physical and chemical stability of the polymer blend. The strong influence of the drying procedure on the stability against photoinduced degradation of the PTB7:PCBM films, produced with solvent additives, is shown with data from UV\textendashvisible (UV\textendashvis), Fourier transform infrared (FTIR) and Raman spectroscopy. The addition of solvent additive molecules DIO:DPE to the PTB7:PCBM blend accelerates the degradation compared with the pristine blend. At higher annealing temperature a removal of the additives is bringing degradation back to the level of the pristine blend films, which is promising for photovoltaic applications.},

keywords = {Foundry Organic, Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {A Novel Multi-Functional Thiophene-Based Organic Cation as Passivation, Crystalline Orientation, and Organic Spacer Agent for Low-Dimensional 3D/1D Perovskite Solar Cells},

author = {A Semerci and A Buyruk and S Emin and R Hooijer and D Kovacheva and P Mayer and M A Reus and D Bl\"{a}tte and M G\"{u}nther and N F Hartmann and S Lotfi and J P Hofmann and P M\"{u}ller-Buschbaum and T Bein and T Ameri},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adom.202300267},

doi = {https://doi.org/10.1002/adom.202300267},

issn = {2195-1071},

journal = {Advanced Optical Materials},

volume = {11},

number = {16},

pages = {2300267},

abstract = {Abstract Recently, the mixed-dimensional (3D/2D or 3D/1D) perovskite solar cells using small organic spacers have attracted interest due to their outstanding long-term stability. Here, a new type of thiophene-based organic cation 2-(thiophene-2yl-)pyridine-1-ium iodide (ThPyI), which is used to fabricate mixed-dimensional 3D/1D perovskite solar cells, is presented. The ThPyI-based 1D perovskitoid is applied as a passivator on top of a 3D methyl ammonium lead iodide (MAPI) to fabricate surface-passivated 3D/1D perovskite films or added alone into the 3D perovskite precursor to generate bulk-passivated 3D MAPI. The 1D perovskitoid acts as a passivating agent at the grain boundaries of surface-passivated 3D/1D, which improves the power conversion efficiency (PCE) of the solar cells. Grazing incidence wide-angle X-ray scattering (GIWAXS) studies confirm that ThPyI triggers the preferential orientation of the bulk MAPI slabs, which is essential to enhance charge transport. Champion bulk-passivated 3D and surface-passivated 3D/1D devices yield 14.10% and 19.60% PCE, respectively. The bulk-passivated 3D offers favorable stability, with 84% PCE retained after 2000 h without encapsulation. This study brings a new perspective to the design of organic spacers having a different binding motif and a passivation strategy to mitigate the impact of defects in hybrid 3D/1D perovskite solar cells.},

keywords = {Foundry Organic, Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Optically addressable spin defects coupled to bound states in the continuum metasurfaces},

author = {L Sortino and A Gale and L K\"{u}hner and C Li and J Biechteler and F J Wendisch and M Kianinia and H Ren and M Toth and S A Maier},

url = {https://arxiv.org/abs/2306.05735},

doi = {https://doi.org/10.48550/arXiv.2306.05735},

journal = {arXiv preprint arXiv:2306.05735},

abstract = {Van der Waals (vdW) materials, including hexagonal boron nitride (hBN), are layered crystalline solids with appealing properties for investigating light-matter interactions at the nanoscale. hBN has emerged as a versatile building block for nanophotonic structures, and the recent identification of native optically addressable spin defects has opened up exciting possibilities in quantum technologies. However, these defects exhibit relatively low quantum efficiencies and a broad emission spectrum, limiting potential applications. Optical metasurfaces present a novel approach to boost light emission efficiency, offering remarkable control over light-matter coupling at the sub-wavelength regime. Here, we propose and realise a monolithic scalable integration between intrinsic spin defects in hBN metasurfaces and high quality (Q) factor resonances leveraging quasi-bound states in the continuum (qBICs). Coupling between spin defect ensembles and qBIC resonances delivers a 25-fold increase in photoluminescence intensity, accompanied by spectral narrowing to below 4 nm linewidth facilitated by Q factors exceeding 10 ^2. Our findings demonstrate a new class of spin based metasurfaces and pave the way towards vdW-based nanophotonic devices with enhanced efficiency and sensitivity for quantum applications in imaging, sensing, and light emission.},

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

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Photoexcitation Control of Excitation Relaxation in Mixed-Phase Ruddlesden-Popper Hybrid Organic-Inorganic Lead-Iodide Perovskites},

author = {A Stadlbauer and L Eyre and A Biewald and F Rauh and M W Heindl and S Liu and J Zerhoch and S Feldmann and A Hartschuh and F Deschler},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adom.202301331},

doi = {https://doi.org/10.1002/adom.202301331},

issn = {2195-1071},

journal = {Advanced Optical Materials},

volume = {n/a},

number = {n/a},

pages = {2301331},

abstract = {Abstract The electronic states and exciton binding energies of layered Ruddlesden-Popper (RP) metal-halide perovskites can be tailored through changes of their chemical composition, yielding multi-phase systems with complex energy cascades. Ultrafast photoexcitation relaxation with transfer dynamics into domains of increasing layer number has been reported for these materials. Here, ultrafast optical spectroscopy is used to report an unexpected excitation energy dependence of photoexcitation relaxation dynamics in mixed-dimensional benzylammonium cesium lead iodide RP perovskite (BeA2CsPb2I7) thin films, which gives rise to spectrally broadband luminescence over the visible region. Using transient absorption and photoluminescence spectroscopy it is found that excitations, which are formed in the n = 2 RP-phase after photoexcitation with ≈0.2 electron volt excess energy, transfer to higher layer number RP-phases on unexpectedly slow timescales of tens of picoseconds. Further, it is observed that such excitations are initially optically passive. Notably, luminescence occurs under these conditions from multiple RP-phases with optical bandgaps across the visible range, yielding broadband luminescence. The results hold potential for realization of broadband white-light emitters and other light-emitting devices.},

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

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Comparison of Harmonic Generation from Crystalline and Amorphous Gallium Phosphide Nanofilms},

author = {B Tilmann and T Huq and T Possmayer and J Dranczewski and B Nickel and H Zhang and L Krivitsky and A I Kuznetsov and L De S. Menezes and S Vezzoli and R Sapienza and S A Maier},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adom.202300269},

doi = {https://doi.org/10.1002/adom.202300269},

issn = {2195-1071},

journal = {Advanced Optical Materials},

volume = {11},

number = {16},

pages = {2300269},

abstract = {Abstract Gallium phosphide (GaP) is a promising material for nanophotonics, given its large refractive index and a transparency over most of the visible spectrum. However, since easy phase-matching is not possible with bulk GaP, a comprehensive study of its nonlinear optical properties for harmonic generation, especially when grown as thin films, is still missing. Here, second harmonic generation is studied from epitaxially grown GaP thin films, demonstrating that the absolute conversion efficiencies are comparable to a bulk wafer over the pump wavelength range from 1060 to 1370 nm. Furthermore, the results are compared to nonlinear simulations, and the second order nonlinear susceptibility is extracted, showing a similar dispersion and magnitude to that of the bulk material. Furthermore, the third order nonlinear susceptibility of amorphous GaP thin films is extracted from third harmonic generation to be more than one order of magnitude larger than that of the crystalline material, and generation of up to the fifth harmonic is reported. The results show the potential of crystalline and amorphous thin films for nonlinear optics with nanoantennas and metasurfaces, particularly in the visible to near infrared part of the spectrum.},

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

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Modulation of electronic and ionic conduction in mixed polymer conductors via additive engineering: Towards targeted applications under varying humidity},

author = {S Tu and T Tian and A Vagias and L F Huber and L Liu and S Liang and R A Fischer and S Bernstorff and P M\"{u}ller-Buschbaum},

url = {https://www.sciencedirect.com/science/article/pii/S1385894723057650},

doi = {https://doi.org/10.1016/j.cej.2023.147034},

issn = {1385-8947},

journal = {Chemical Engineering Journal},

volume = {477},

pages = {147034},

abstract = {Polymer solids with mixed ion and electron transport hold great promise for next-generation organic electronics, and rational regulation of ionic/electronic contribution within these materials can enable a broadened spectrum of practical applications. However, a fundamental understanding of the conduction mechanisms and their correlations with morphological characteristics remains limited, especially under varying environmental humidity conditions. In the present work, simple additive engineering enables the effective regulation of electronic and ionic contribution in poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) based conductors, giving rising to ion- and/or electron-dominant conductions. As a demonstration, PEDOT:PSS films with different electrical characteristics are successfully applied for thermal energy harvesting, healthcare monitoring and human motion detection upon humidity exposure. Combining operando alternating current (AC) impedance spectroscopy and grazing incidence small-angle X-ray scattering at low and high humidity levels, additive-dependent charge transport mechanisms are elucidated, and correlations between morphological alterations and conductivity evolutions are revealed. This work achieves highly tailorable PEDOT:PSS conduction utilizing Zonyl, dimethyl sulfoxide (DMSO) and carbon nanotubes (CNTs) as additives with distinct humidity responses and gains an in-depth comprehension of underlying mechanisms, which are expected to pave the way for next-generation organic electronics.},

keywords = {Foundry Organic, Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Fluorescence enhancement in topologically optimized gallium phosphide all-dielectric nanoantennas},

author = {C Vidal and B Tilmann and S Tiwari and T Raziman and S A Maier and J Wenger and R Sapienza},

url = {https://arxiv.org/abs/2310.07309},

doi = {https://doi.org/10.48550/arXiv.2310.07309},

journal = {arXiv preprint arXiv:2310.07309},

abstract = {Nanoantennas capable of large fluorescence enhancement with minimal absorption are crucial for future optical technologies from single-photon sources to biosensing. Efficient dielectric nanoantennas have been designed, however, evaluating their performance at the individual emitter level is challenging due to the complexity of combining high-resolution nanofabrication, spectroscopy and nanoscale positioning of the emitter. Here, we study the fluorescence enhancement in infinity-shaped gallium phosphide (GaP) nanoantennas based on a topologically optimized design. Using fluorescence correlation spectroscopy (FCS), we probe the nanoantennas enhancement factor and observed an average of 63-fold fluorescence brightness enhancement with a maximum of 93-fold for dye molecules in nanogaps between 20 nm and 50 nm. The experimentally determined fluorescence enhancement of the nanoantennas was confirmed by numerical simulations of the local density of optical states (LDOS). Furthermore, we show that beyond design optimisation of dielectric nanoantennas, increased performances can be achieved via tailoring of nanoantenna fabrication.},

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

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Direct Bottom-Up In Situ Growth: A Paradigm Shift for Studies in Wet-Chemical Synthesis of Gold Nanoparticles},

author = {G A Vinnacombe-Willson and Y Conti and A Stefancu and P S Weiss and E Cort\'{e}s and L Scarabelli},

url = {https://doi.org/10.1021/acs.chemrev.2c00914},

doi = {10.1021/acs.chemrev.2c00914},

issn = {0009-2665},

journal = {Chemical Reviews},

volume = {123},

number = {13},

pages = {8488-8529},

abstract = {Plasmonic gold nanoparticles have been used increasingly in solid-state systems because of their applicability in fabricating novel sensors, heterogeneous catalysts, metamaterials, and thermoplasmonic substrates. While bottom-up colloidal syntheses take advantage of the chemical environment to control size, shape, composition, surface chemistry, and crystallography of the nanostructures precisely, it can be challenging to assemble nanoparticles rationally from suspension onto solid supports or within devices. In this Review, we discuss a powerful recent synthetic methodology, bottom-up in situ substrate growth, which circumvents time-consuming batch presynthesis, ligand exchange, and self-assembly steps by applying wet-chemical synthesis to form morphologically controlled nanostructures on supporting materials. First, we briefly introduce the properties of plasmonic nanostructures. Then we comprehensively summarize recent work that adds to the synthetic understanding of in situ geometrical and spatial control (patterning). Next, we briefly discuss applications of plasmonic hybrid materials prepared by in situ growth. Overall, despite the vast potential advantages of in situ growth, the mechanistic understanding of these methodologies remains far from established, providing opportunities and challenges for future research.},

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

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Probing Charge-Transfer Processes in a Covalently Linked [Ge9]-Cluster Imine Dyad},

author = {C Wallach and Y Selic and F S Geitner and A Kumar and E Thyrhaug and J Hauer and A J Karttunen and T F F\"{a}ssler},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.202304088},

doi = {https://doi.org/10.1002/anie.202304088},

issn = {1433-7851},

journal = {Angewandte Chemie International Edition},

volume = {62},

number = {29},

pages = {e202304088},

abstract = {Abstract C60 donor dyads in which the carbon cage is covalently linked to an electron-donating unit have been discussed as one possibility for an electron-transfer system, and it has been shown that spherical [Ge9] cluster anions show a close relation to fullerenes with respect to their electronic structure. However, the optical properties of these clusters and of functionalized cluster derivatives are almost unknown. We now report on the synthesis of the intensely red [Ge9] cluster linked to an extended π-electron system. [Ge9Si(TMS)32CH3C=N-DAB(II)Dipp]− (1−) is formed upon the reaction of [Ge9Si(TMS)32]2− with bromo-diazaborole DAB(II)Dipp-Br in CH3CN (TMS=trimethylsilyl; DAB(II)=1,3,2-diazaborole with an unsaturated backbone; Dipp=2,6-di-iso-propylphenyl). Reversible protonation of the imine entity in 1− yields the deep green, zwitterionic cluster [Ge9Si(TMS)32CH3C=N(H)-DAB(II)Dipp] (1-H) and vice versa. Optical spectroscopy combined with time-dependent density functional theory suggests a charge-transfer excitation between the cluster and the antibonding π* orbital of the imine moiety as the cause of the intense coloration. An absorption maximum of 1-H in the red region of the electromagnetic spectrum and the corresponding lowest-energy excited state at λ=669 nm make the compound an interesting starting point for further investigations targeting the design of photo-active cluster compounds.},

keywords = {Foundry Organic, Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Isolating Pure Donor and Acceptor Signals by Polarization-Controlled Transient Absorption Spectroscopy},

author = {Y Xu and L Mewes and E Thyrhaug and V Sl\'{a}ma and F \v{S}anda and H Langhals and J Hauer},

url = {https://doi.org/10.1021/acs.jpclett.3c01451},

doi = {10.1021/acs.jpclett.3c01451},

journal = {The Journal of Physical Chemistry Letters},

volume = {14},

number = {23},

pages = {5390-5396},

abstract = {The optical spectra of molecules are often highly congested, inhibiting definite assignment of features and dynamics. In this work, we demonstrate and apply a polarization-based strategy for the decomposition of time-resolved optical spectra to analyze the electronic structure and energy transfer in a molecular donor\textendashacceptor (D\textendashA) dyad. We choose a dyad with orthogonal transition dipole moments for D and A and high fluorescence quantum yield to show that polarization-controlled ultrafast transient absorption spectra can isolate the pure D and A parts of the total signal. This provides a strategy to greatly reduce spectral congestion in complex systems and thus allows for detailed studies of electronic structure and electronic energy transfer.},

keywords = {Foundry Organic, Molecularly-Functionalized},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Highly Efficient Decomposition of Perfluorocarbons for over 1000 Hours via Active Site Regeneration},

author = {H Zhang and T Luo and Y Chen and K Liu and H Li and E Pensa and J Fu and Z Lin and L Chai and E Cort\'{e}s and M Liu},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.202305651},

doi = {https://doi.org/10.1002/anie.202305651},

issn = {1433-7851},

journal = {Angewandte Chemie International Edition},

volume = {62},

number = {46},

pages = {e202305651},

abstract = {Abstract Tetrafluoromethane (CF4), the simplest perfluorocarbon (PFC), has the potential to exacerbate global warming. Catalytic hydrolysis is a viable method to degrade CF4, but fluorine poisoning severely restricts both the catalytic performance and catalyst lifetime. In this study, Ga is introduced to effectively assists the defluorination of poisoned Al active sites, leading to highly efficient CF4 decomposition at 600 °C with a catalytic lifetime exceeding 1,000 hours. 27Al and 71Ga magic-angle spinning nuclear magnetic resonance spectroscopy (MAS NMR) showed that the introduced Ga exists as tetracoordinated Ga sites (GaIV), which readily dissociate water to form Ga−OH. In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and density function theory (DFT) calculations confirmed that Ga−OH assists the defluorination of poisoned Al active sites via a dehydration-like process. As a result, the Ga/Al2O3 catalyst achieved 100 % CF4 decomposition keeping an ultra-long catalytic lifetime and outperforming reported results. This work proposes a new approach for efficient and long-term CF4 decomposition by promoting the regeneration of active sites.},

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

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {All-Dielectric Structural Coloration Empowered by Bound States in the Continuum},

author = {H Zheng and H Hu and T Weber and J Wang and L Nan and B Zou and S A Maier and A Tittl},

url = {https://arxiv.org/abs/2311.13315},

doi = {https://doi.org/10.48550/arXiv.2311.13315},

journal = {arXiv preprint arXiv:2311.13315},

abstract = {The technological requirements of low-power and high-fidelity color displays have been instrumental in driving research into advanced coloration technologies. At the forefront of these developments is the implementation of dye-free coloration techniques, which overcome previous constraints related to insufficient resolution and color fading. In this context, resonant dielectric nanostructures have emerged as a promising paradigm, showing great potential for high efficiency, remarkably high color saturation, wide gamut palette, and realistic image reproduction. However, they still face limitations related to color accuracy, purity, and simultaneous brightness tunability. Here, we demonstrate an all-dielectric metasurface empowered by photonic bound states in the continuum (BICs), which supports sharp resonances throughout the visible spectral range, ideally suited for producing a wide range of structural colors. The metasurface design consists of titanium dioxide (TiO2) ellipses with carefully controlled sizes and geometrical asymmetry, allowing versatile and on-demand variation of the brightness and hue of the output colors, respectively.},

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

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Breaking K+ Concentration Limit on Cu Nanoneedles for Acidic Electrocatalytic CO2 Reduction to Multi-Carbon Products},

author = {X Zi and Y Zhou and L Zhu and Q Chen and Y Tan and X Wang and M Sayed and E Pensa and R A Geioushy and K Liu and J Fu and E Cort\'{e}s and M Liu},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.202309351},

doi = {https://doi.org/10.1002/anie.202309351},

issn = {1433-7851},

journal = {Angewandte Chemie International Edition},

volume = {62},

number = {42},

pages = {e202309351},

abstract = {Abstract Electrocatalytic CO2 reduction reaction (CO2RR) to multi-carbon products (C2+) in acidic electrolyte is one of the most advanced routes for tackling our current climate and energy crisis. However, the competing hydrogen evolution reaction (HER) and the poor selectivity towards the valuable C2+ products are the major obstacles for the upscaling of these technologies. High local potassium ions (K+) concentration at the cathode's surface can inhibit proton-diffusion and accelerate the desirable carbon-carbon (C−C) coupling process. However, the solubility limit of potassium salts in bulk solution constrains the maximum achievable K+ concentration at the reaction sites and thus the overall acidic CO2RR performance of most electrocatalysts. In this work, we demonstrate that Cu nanoneedles induce ultrahigh local K+ concentrations (4.22 M) \textendash thus breaking the K+ solubility limit (3.5 M) \textendash which enables a highly efficient CO2RR in 3 M KCl at pH=1. As a result, a Faradaic efficiency of 90.69±2.15 % for C2+ (FEC2+) can be achieved at 1400 mA.cm−2, simultaneous with a single pass carbon efficiency (SPCE) of 25.49±0.82 % at a CO2 flow rate of 7 sccm.},

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

pubstate = {published},

tppubtype = {article}

}