Publications

@article{nokey,

title = {Optically Active Perovskite CsPbBr3 Nanocrystals Helically Arranged on Inorganic Silica Nanohelices},

author = {P Liu and W Chen and Y Okazaki and Y Battie and L Brocard and M Decossas and E Pouget and P M\"{u}ller-Buschbaum and B Kauffmann and S Pathan and T Sagawa and R Oda},

url = {https://doi.org/10.1021/acs.nanolett.0c02013},

doi = {10.1021/acs.nanolett.0c02013},

issn = {1530-6984},

year  = {2020},

date = {2020-09-03},

urldate = {2020-09-03},

journal = {Nano Letters},

volume = {20},

number = {12},

pages = {8453-8460},

abstract = {Perovskite nanocrystals (PNCs) exhibit excellent absorption and luminescent properties. Inorganic silica right (or left) handed nanohelices are used as chiral templates to induce optically active properties to CsPbBr3 PNCs grafted on their surfaces. In suspension, PNCs grafted on the nanohelices do not show any detectable chiroptical properties. In contrast, in a dried film state, they show large circular dichroism (CD) and circularly polarized luminescence (CPL) signals with dissymmetric factor up to 6 × 10\textendash3. Grazing incidence X-ray scattering, tomography, and cryo-electron microscopy (EM) have shown closely and helically packed PNCs on the dried helices and much more loosely organized PNCs on helices in suspension. Simulations based on the coupled dipole method (CDM) demonstrate that the CD comes from the dipolar interaction between PNC assembled into a chiral structure and the CD decreases with the interparticle distance.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Light-Induced and Oxygen-Mediated Degradation Processes in Photoactive Layers Based on PTB7-Th},

author = {F C L\"{o}hrer and C Senfter and C J Schaffer and J Schlipf and D Mosegu\'{i} Gonz\'{a}lez and P Zhang and S V Roth and P M\"{u}ller-Buschbaum},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adpr.202000047},

doi = {https://doi.org/10.1002/adpr.202000047},

issn = {2699-9293},

year  = {2020},

date = {2020-08-26},

urldate = {2020-08-26},

journal = {Advanced Photonics Research},

volume = {1},

number = {1},

pages = {2000047},

abstract = {Low-bandgap polymers are sensitive to various degradation processes, which strongly decrease their lifetime. The chemical and physical changes occurring in the low-bandgap polymer with benzodithiophene units poly[4,8-bis(5-(2-ethylhexyl)thiophene-2-yl)benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl-alt-(4-(2-ethylhexyl)-3-fluorothieno[3,4-b]thiophene-2-carboxylate] (PTB7-Th) and its blend with the fullerene derivative [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) are followed during irradiation-induced aging by combination of various characterization methods. The active layer morphology is investigated using atomic force microscopy (AFM) as well as in-operando grazing incidence small angle X-ray scattering (GISAXS), indicating morphological alterations and material loss due to chemical modifications. Optical spectroscopy gives insights into these chemical processes which lead to significant absorption losses under ambient conditions. Independent of the energy of the absorbed photons, but only in combination with oxygen, the excitation of the polymer leads to a fatal increase in oxidation probability. Fourier transform infrared (FTIR) data highlight the sensitivity of the conjugated polymer backbone to oxidation, a result of lost conjugation and therefore absorption capability. With combined AFM height and infrared (IR) mapping, the chemical degradation and material loss is confirmed on a nanoscale. Although the chemical structure is seriously damaged, the blend morphology is not undergoing major changes.},

keywords = {Foundry Organic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Local Disorder at the Phase Transition Interrupts Ambipolar Charge Carrier Transport in Large Crystal Methylammonium Lead Iodide Thin Films},

author = {A Biewald and N Giesbrecht and T Bein and P Docampo and A Hartschuh and R Ciesielski},

url = {https://doi.org/10.1021/acs.jpcc.0c06240},

doi = {10.1021/acs.jpcc.0c06240},

issn = {1932-7447},

year  = {2020},

date = {2020-08-25},

journal = {The Journal of Physical Chemistry C},

volume = {124},

number = {38},

pages = {20757-20764},

abstract = {The low-temperature transition from a tetragonal to an orthorhombic crystal phase in methylammonium lead iodide (MAPI) is accompanied by drastic changes in the charge carrier mobility around a critical temperature of approximately 164 K. This transition is studied here using photoluminescence (PL) microscopy on large crystal MAPI thin films, which is extremely sensitive to modifications of the charge carrier dynamics and can resolve physical properties on a single-grain level. The key observation is that ambipolar charge carrier diffusion suddenly stops when the temperature falls below the phase transition temperature. From coexisting PL bands and their spatial distribution, it is concluded that the temperature range from just below the phase transition until about 150 K is determined by a mixed phase where small orthorhombic and tetragonal domains coexist. This results in local disorder, which hinders ambipolar charge carrier diffusion.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Atomistic defects as single-photon emitters in atomically thin MoS2},

author = {K Barthelmi and J Klein and A H\"{o}tger and L Sigl and F Sigger and E Mitterreiter and S Rey and S Gyger and M Lorke and M Florian and F Jahnke and T Taniguchi and K Watanabe and V Zwiller and K D J\"{o}ns and U Wurstbauer and C Kastl and A Weber-Bargioni and J J Finley and K M\"{u}ller and A W Holleitner},

url = {https://doi.org/10.1063/5.0018557},

doi = {10.1063/5.0018557},

issn = {0003-6951},

year  = {2020},

date = {2020-08-17},

journal = {Applied Physics Letters},

volume = {117},

number = {7},

pages = {070501},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {In Situ Studies of Solvent Additive Effects on the Morphology Development during Printing of Bulk Heterojunction Films for Organic Solar Cells},

author = {D Yang and S Grott and X Jiang and K S Wienhold and M Schwartzkopf and S V Roth and P M\"{u}ller-Buschbaum},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/smtd.202000418},

doi = {https://doi.org/10.1002/smtd.202000418},

issn = {2366-9608},

year  = {2020},

date = {2020-08-09},

urldate = {2020-08-09},

journal = {Small Methods},

volume = {4},

number = {9},

pages = {2000418},

abstract = {Abstract The development of polymer morphology and crystallinity of printed bulk heterojunction (BHJ) films doped with the different solvent additives 1,8-diiodooctane (DIO) or diphenyl ether (DPE) is investigated with in situ grazing-incidence small/wide-angle X-ray scattering. The solvent additives, having different boiling points, lead to a different film drying behavior and morphology growth states in the BHJ films of the benzothiadiazole-based polymer (PPDT2FBT) and [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM). The phase demixing in the printed films is changing over time along with solvent evaporation. Polymer domains start aggregating to form larger domains in the liquid\textendashliquid phase, while phase separation mainly occurs in the liquid\textendashsolid phase. The present work provides a profound insight into the morphology development of printed BHJ films doped with different solvent additives, which is particularly important for the large-scale fabrication of organic photovoltaics.},

keywords = {Foundry Organic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Following In Situ the Evolution of Morphology and Optical Properties during Printing of Thin Films for Application in Non-Fullerene Acceptor Based Organic Solar Cells},

author = {K S Wienhold and C L Weindl and S Yin and T Tian and M Schwartzkopf and A Rothkirch and S V Roth and P M\"{u}ller-Buschbaum},

url = {https://doi.org/10.1021/acsami.0c12390},

doi = {10.1021/acsami.0c12390},

issn = {1944-8244},

year  = {2020},

date = {2020-08-07},

urldate = {2020-08-07},

journal = {ACS Applied Materials \& Interfaces},

volume = {12},

number = {36},

pages = {40381-40392},

abstract = {In situ printing gives insight into the evolution of morphology and optical properties during slot-die coating of active layers for application in organic solar cells and enables an upscaling and optimization of the thin film deposition process and the photovoltaic performance. Active layers based on the conjugated polymer donor with benzodithiophene units PBDB-T-2Cl and the non-fullerene small-molecule acceptor IT-4F are printed with a slot-die coating technique and probed in situ with grazing incidence small-angle X-ray scattering, grazing incidence wide-angle X-ray scattering, and ultraviolet/visible light spectroscopy. The formation of the morphology is followed from the liquid state to the final dry film for different printing conditions (at 25 and 35 °C), and five regimes of film formation are determined. The morphological changes are correlated to changing optical properties. During the film formation, crystallization of the non-fullerene small-molecule acceptor takes place and polymer domains with sizes of some tens of nanometers emerge. A red shift of the optical band gap and a broadening of the absorbance spectrum occurs, which allow for exploiting the sun spectrum more efficiently and are expected to have a favorable effect on the solar cell performance.},

keywords = {Foundry Organic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Solution-processed p-type nanocrystalline CoO films for inverted mixed perovskite solar cells},

author = {B Li and Y C Rui and J L Xu and Y Q Wang and J X Yang and Q H Zhang and P Muller-Buschbaum},

url = {\<Go to ISI\>://WOS:000533529500009},

doi = {10.1016/j.jcis.2020.03.119},

issn = {0021-9797},

year  = {2020},

date = {2020-08-01},

journal = {Journal of Colloid and Interface Science},

volume = {573},

pages = {78-86},

abstract = {Inorganic p-type materials show great potential as the hole transport layer in perovskite solar cells with the merits of low costs and enhanced chemical stability. As a p-type material, cobalt oxide (CoO) has received so far not that level of attention despite its high hole mobility. Herein, solution-processed p-type CoO nanocrystalline films are developed for inverted mixed perovskite solar cells. The ultrafine CoO nanocrystals are synthesized via an oil phase method, which are subsequently treated by a ligand exchange process using pyridine solvent to remove the long alkyl chains covering the nanocrystals. From this homogeneous colloidal solution CoO films are obtained, which exhibit a smooth and pinhole free surface morphology with high transparency and good conductivity. The ultraviolet photoelectron spectrum also indicates that the energy levels of the CoO film match well with the mixed perovskite Cs-0(.05)(FA(0)(.)(83)MA(0)(.17))(0.95)(I0.83Br0.17)(3). Inverted solar cells based on crystalline Co0 films with ligand exchange show a reasonable energy conversion efficiency, whereas devices based on CoO films without ligand exchange suffer from a strong S-shape JV-characteristic. Thus, the crystalline CoO films are foreseen to pave a new way of inorganic hole transport materials in the fields of perovskite solar cells. (C) 2020 Elsevier Inc. All rights reserved.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {All-Dielectric Silicon Nanoslots for Er3+ Photoluminescence Enhancement},

author = {B Kalinic and T Cesca and S Mignuzzi and A Jacassi and I G Balasa and S A Maier and R Sapienza and G Mattei},

url = {\<Go to ISI\>://WOS:000553352700004},

doi = {10.1103/PhysRevApplied.14.014086},

issn = {2331-7019},

year  = {2020},

date = {2020-07-28},

journal = {Physical Review Applied},

volume = {14},

number = {1},

abstract = {We study, both experimentally and theoretically, the modification of Er3+ photoluminescence properties in Si dielectric nanoslots. The ultrathin nanoslot (down to 5-nm thickness), filled with Er in SiO2, boosts the electric and magnetic local density of states via coherent near-field interaction. We report an experimental 20-fold enhancement of the radiative decay rate with negligible losses. Moreover, via modifying the geometry of the all-dielectric nanoslot, the outcoupling of the emitted radiation to the far field can be strongly improved, without affecting the strong decay-rate enhancement given by the nanoslot structure. Indeed, for a periodic square array of slotted nanopillars an almost one-order-of-magnitude-higher Er3+ PL intensity is measured with respect to the unpatterned structures. This has a direct impact on the design of more efficient CMOS-compatible light sources operating at telecom wavelengths.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Unique Behavior of Halide Double Perovskites with Mixed Halogens},

author = {D Han and M Ogura and A Held and H Ebert},

url = {https://doi.org/10.1021/acsami.0c08240},

doi = {10.1021/acsami.0c08240},

issn = {1944-8244},

year  = {2020},

date = {2020-07-23},

urldate = {2020-07-23},

journal = {ACS Applied Materials \& Interfaces},

volume = {12},

number = {33},

pages = {37100-37107},

abstract = {Engineering halide double perovskite (A2M+M3+XVII6) by mixing elements is a viable way to tune its electronic and optical properties. In spite of many emerging experiments on halide double perovskite alloys, the basic electronic properties of the alloys have not been fully understood. In this work, we chose Cs2AgBiCl6 as an example and systematically studied electronic properties of its different site alloys Cs2NaxAg1\textendashxBiCl6, Cs2AgSbxBi1\textendashxCl6, and Cs2AgBi(BrxCl1\textendashx)6 (x = 0.25, 0.5, 0.75) by first-principles calculations. Interestingly, the halogen site alloy shows opposite behavior to M+ and M3+ cation site alloys; that is, Cs2AgBi(BrxCl1\textendashx)6 displays virtual crystal behavior without substantial broadening, while Cs2NaxAg1\textendashxBiCl6 and Cs2AgSbxBi1\textendashxCl6 show split-band behaviors with substantial broadening, which indicates that lifetimes of electrons and holes in Cs2AgBi(BrxCl1\textendashx)6 would be longer than those in Cs2NaxAg1\textendashxBiCl6 and Cs2AgSbxBi1\textendashxCl6. We further found that long lifetimes of electrons and holes are common for mixed halide perovskites. Moreover, the band alignment is provided to determine the band gap change of alloys and to understand the transport of electrons and holes when these pure compounds form heterostructures. Our systematical studies should be helpful for future optoelectronic applications of halide perovskites.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Machine-Learned Charge Transfer Integrals for Multiscale Simulations in Organic Thin Films},

author = {M Rinderle and W Kaiser and A Mattoni and A Gagliardi},

url = {https://doi.org/10.1021/acs.jpcc.0c04355},

doi = {10.1021/acs.jpcc.0c04355},

issn = {1932-7447},

year  = {2020},

date = {2020-07-20},

journal = {The Journal of Physical Chemistry C},

volume = {124},

number = {32},

pages = {17733-17743},

abstract = {Gaining insight into structure\textendashproperty relations is a key factor for the development of organic electronics. We present a multiscale framework for charge carrier mobilities in organic thin films empowered by machine-learned charge transfer integrals. The choice of the molecular representation is crucial for accurate and sensitive predictions. Using pentacene thin films, we investigate kernel based algorithms and systematically compare representations ranging from system-specific geometric to Coulomb matrix features to predict absolute and logarithmic transfer integrals. We use the predicted transfer integrals to compute the mobility, including its anisotropy, and compare it to reference values. Best accuracies were obtained by models using the interaction part of the Coulomb matrix as a feature and the logarithm of the transfer integral as a target. We achieve R2 values of 0.97 for transfer integrals within an extensive range of 20 orders of magnitude and less than 27% error in the mobility. We show the transferability of the CIP feature for tetracene and DNTT with excellent prediction accuracies. Furthermore, we demonstrate that the interaction part of the CM successfully encodes the molecular identity and provides a highly sensitive ML framework. The presented framework opens the possibility for highly accurate mesoscopic transport simulations saving orders of magnitude in computational cost.},

keywords = {Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Doping Dependent In-Plane and Cross-Plane Thermoelectric Performance of Thin n-Type Polymer P(NDI2OD-T2) Films},

author = {R M Kluge and N Saxena and W Chen and V Korstgens and M Schwartzkopf and Q Zhong and S V Roth and P Muller-Buschbaum},

url = {\<Go to ISI\>://WOS:000535017100001},

doi = {10.1002/adfm.202003092},

issn = {1616-301X},

year  = {2020},

date = {2020-07-09},

urldate = {2020-07-09},

journal = {Advanced Functional Materials},

volume = {30},

number = {28},

abstract = {Thermoelectric generators pose a promising approach in renewable energies as they can convert waste heat into electricity. In order to build high efficiency devices, suitable thermoelectric materials, both n- and p-type, are needed. Here, the n-type high-mobility polymer poly[N,N '-bis(2-octyldodecyl)naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5 '-(2,2 '-bithiophene) (P(NDI2OD-T2)) is focused upon. Via solution doping with 4-(1,3-dimethyl-2,3-dihydro-1H-benzoimidazol-2-yl)-N,N-diphenylaniline (N-DPBI), a maximum power factor of (1.84 +/- 0.13) mu W K-2 m(-1) is achieved in an in-plane geometry for 5 wt% dopant concentration. Additionally, UV-vis spectroscopy and grazing-incidence wide-angle X-ray scattering are applied to elucidate the mechanisms of the doping process and to explain the discrepancy in thermoelectric performance depending on the charge carriers being either transported in-plane or cross-plane. Morphological changes are found such that the crystallites, built-up by extended polymer chains interacting via lamellar and pi-pi stacking, re-arrange from face- to edge-on orientation upon doping. At high doping concentrations, dopant molecules disturb the crystallinity of the polymer, hindering charge transport and leading to a decreased power factor at high dopant concentrations. These observations explain why an intermediate doping concentration of N-DPBI leads to an optimized thermoelectric performance of P(NDI2OD-T2) in an in-plane geometry as compared to the cross-plane case.},

keywords = {Foundry Organic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Electronic structure investigation of wide band gap semiconductors\textemdashMg2PN3 and Zn2PN3: experiment and theory},

author = {Al M F Fattah and M R Amin and M Mallmann and S Kasap and W Schnick and A Moewes},

url = {http://dx.doi.org/10.1088/1361-648X/ab8f8a},

doi = {10.1088/1361-648x/ab8f8a},

issn = {0953-8984 

1361-648X},

year  = {2020},

date = {2020-07-06},

journal = {Journal of Physics: Condensed Matter},

volume = {32},

number = {40},

pages = {405504},

abstract = {The research on nitridophosphate materials has gained significant attention in recent years due to the abundance of elements like Mg, Zn, P, and N. We present a detailed study of band gap and electronic structure of M2PN3 (M = Mg, Zn), using synchrotron-based soft x-ray spectroscopy measurements as well as density functional theory (DFT) calculations. The experimental N K-edge x-ray emission spectroscopy (XES) and x-ray absorption spectroscopy (XAS) spectra are used to estimate the band gaps, which are compared with our calculations along with the values available in literature. The band gap, which is essential for electronic device applications, is experimentally determined for the first time to be 5.3 ± 0.2 eV and 4.2 ± 0.2 eV for Mg2PN3 and Zn2PN3, respectively. The experimental band gaps agree well with our calculated band gaps of 5.4 eV for Mg2PN3 and 3.9 eV for Zn2PN3, using the modified Becke\textendashJohnson (mBJ) exchange potential. The states that contribute to the band gap are investigated with the calculated density of states especially with respect to two non-equivalent N sites in the structure. The calculations and the measurements predict that both materials have an indirect band gap. The wide band gap of M2PN3 (M = Mg, Zn) could make it promising for the application in photovoltaic cells, high power RF applications, as well as power electronic devices.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Tailoring the orientation of perovskite crystals via adding two-dimensional polymorphs for perovskite solar cells},

author = {R Guo and A Buyruk and X Jiang and W Chen and L K Reb and M A Scheel and T Ameri and P M\"{u}ller-Buschbaum},

url = {http://dx.doi.org/10.1088/2515-7655/ab90d0},

doi = {10.1088/2515-7655/ab90d0},

issn = {2515-7655},

year  = {2020},

date = {2020-07-03},

urldate = {2020-07-03},

journal = {Journal of Physics: Energy},

volume = {2},

number = {3},

pages = {034005},

abstract = {Organic-inorganic perovskite materials are attracting increasing attention for their use in high-performance solar cells due to their outstanding properties, such as long diffusion lengths, low recombination rate, and tunable bandgap. Finding an effective method of defect passivation is thought to be a promising route for improvements toward narrowing the distribution of the power conversion efficiency (PCE) values, given by the spread in the PCE over different devices fabricated under identical conditions, for easier commercialization. In this work, we add 2‐(4‐fluoroph-enyl)ethyl ammonium iodide (p-f-PEAI) into the bulk of a mixed cation lead halide perovskite (CH3NH3PbBr3)0.15(HC(NH2)2PbI3)0.85 thin film. We investigate the influence of different p-f-PEAI concentrations on the optical properties, morphology, crystal orientation, charge carrier dynamics, and device performance. We observe that introducing the proper amount of p-f-PEAI changes the preferential orientation of the perovskite crystals, promotes the strength of the crystal textures, and suppresses non-radiative charge recombination. Thus, we obtain a narrower distribution of the PCE of perovskite solar cells (PSCs) without sacrificing the PCE values reached. This is an important step toward better reproducibility to realize the commercialization of PSCs.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Discrete interactions between a few interlayer excitons trapped at a MoSe 2\textendashWSe 2 heterointerface},

author = {M Kremser and M Brotons-Gisbert and J Kn\"{o}rzer and J G\"{u}ckelhorn and M Meyer and M Barbone and A V Stier and B D Gerardot and K M\"{u}ller and J J Finley},

issn = {2397-7132},

year  = {2020},

date = {2020-06-24},

journal = {npj 2D Materials and Applications},

volume = {4},

number = {1},

pages = {1-6},

keywords = {Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Genetic-Algorithm-Aided Meta-Atom Multiplication for Improved Absorption and Coloration in Nanophotonics},

author = {C X Liu and S A Maier and G X Li},

url = {\<Go to ISI\>://WOS:000551497000018},

doi = {10.1021/acsphotonics.0c00266},

issn = {2330-4022},

year  = {2020},

date = {2020-06-15},

journal = {Acs Photonics},

volume = {7},

number = {7},

pages = {1716-1722},

abstract = {For a repertoire of nanophotonic systems, including photonic crystals, metasurfaces, and plasmonic structures, unit cell with a single element is conventionally used for the simplicity of design. The extension of the unit cell with multiple meta-atoms drastically enlarges the parameter space and consequently provides potential configurations with improved device performance. Simultaneously, the multiplication does not induce additional complexity for lithography-based fabrications. However, the substantially increased number of parameters makes the design methodology based on physical intuition and parameter sweep impractical. Here, we show that expanding the number of meta-atoms in the unit cell significantly improves the performance of nanophotonic systems by the virtue of a genetic algorithm-based optimizer. Our approach includes physical intuition endowed in the geometry of meta-atoms, providing additional physical understanding of the optimization process. We demonstrate two photonic applications, including prominent enhancement of a broadband absorption and enlargement of the color coverage of plasmonic nanostructures. Not limited to the two proof-of-concept demonstrations, this methodology can be applied to all meta-atom-based nanophotonic systems, including plasmonic near-field enhancement and nonlinear frequency conversion, as well as a simultaneous control of phase and polarization for metasurfaces.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Thickness-Dependence of Exciton-Exciton Annihilation in Halide Perovskite Nanoplatelets},

author = {M Gramlich and B J Bohn and Y Tong and L Polavarapu and J Feldmann and A S Urban},

url = {\<Go to ISI\>://WOS:000547468400064},

doi = {10.1021/acs.jpclett.0c01291},

issn = {1948-7185},

year  = {2020},

date = {2020-06-14},

journal = {Journal of Physical Chemistry Letters},

volume = {11},

number = {13},

pages = {5361-5366},

abstract = {Exciton-exciton annihilation (EEA) and Auger recombination are detrimental processes occurring in semiconductor optoelectronic devices at high carrier densities. Despite constituting one of the main obstacles for realizing lasing in semiconductor nanocrystals (NCs), the dependencies on NC size are not fully understood, especially for those with both weakly and strongly confined dimensions. Here, we use differential transmission spectroscopy to investigate the dependence of EEA on the physical dimensions of thickness-controlled 2D halide perovskite nanoplatelets (NPIs). We find the EEA lifetimes to be extremely short on the order of 7-60 ps. Moreover, they are strongly determined by the NP1 thickness with a power law dependence according to tau(2) proportional to d(5.3). Additional measurements show that the EEA lifetimes also increase for NPIs with larger lateral dimensions. dimensions is critical for deciphering the fundamental laws governing These results show that a precise control of the physical the process especially in 1D and 2D NCs.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Balancing the pre-aggregation and crystallization kinetics enables high efficiency slot-die coated organic solar cells with reduced non-radiative recombination losses},

author = {B Lin and X Zhou and H Zhao and J Yuan and K Zhou and K Chen and H Wu and R Guo and M A Scheel and A Chumakov and S V Roth and Y Mao and L Wang and Z Tang and P M\"{u}ller-Buschbaum and W Ma},

url = {http://dx.doi.org/10.1039/D0EE00774A},

doi = {10.1039/D0EE00774A},

issn = {1754-5692},

year  = {2020},

date = {2020-06-12},

journal = {Energy \& Environmental Science},

volume = {13},

number = {8},

pages = {2467-2479},

abstract = {Slot-die coating being compatible with the roll-to-roll technique has been regarded as a promising tool for upscaling the manufacturing of organic solar cells (OSCs). However, there has been a significant gap between the efficiencies of the state-of-the-art spin-coated devices and the scalable processed devices. The active layer morphology is crucial to achieve high efficiency in OSCs, which depends on the conditions of film fabrication. To figure out and optimize the slot-die coating process, a deeper understanding of the film formation kinetics is important. Herein, in situ measurements of the slot-die coating process based on the PM7:IT4F system are demonstrated to illustrate the aggregation and crystallization evolution at various die temperatures and substrate temperatures. OSCs with a high power conversion efficiency of 13.2% are achieved at 60 °C die temperature/60 °C substrate temperature due to the improved exciton dissociation, charge transport and suppressed non-radiative charge recombination. The optimized morphology is attributed to the balanced polymer pre-aggregation and small molecule crystallization kinetics. The unsuitable die temperature leads to overlarge phase separation and consequently inefficient exciton dissociation while the improper substrate temperature results in weak crystallization and the following shrunken carrier lifetime with strong non-radiative combination. This work provides fundamental understanding on the correlations among processing methodology, solution pre-aggregation, morphology formation kinetics, device physics and device performance and affords guidance for device optimization in scalable manufacturing.},

keywords = {Foundry Organic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Near-Field Spectroscopy of Cylindrical Phonon-Polariton Antennas},

author = {A Mancini and C R Gubbin and R Bert\'{e} and F Martini and A Politi and E Cort\'{e}s and Y Li and S De Liberato and S A Maier},

url = {https://doi.org/10.1021/acsnano.0c02784},

doi = {10.1021/acsnano.0c02784},

issn = {1936-0851},

year  = {2020},

date = {2020-06-12},

urldate = {2020-06-12},

journal = {ACS Nano},

volume = {14},

number = {7},

pages = {8508-8517},

abstract = {Surface phonon polaritons (SPhPs) are hybrid light\textendashmatter states in which light strongly couples to lattice vibrations inside the Reststrahlen band of polar dielectrics at mid-infrared frequencies. Antennas supporting localized surface phonon polaritons (LSPhPs) easily outperform their plasmonic counterparts operating in the visible or near-infrared in terms of field enhancement and confinement thanks to the inherently slower phonon\textendashphonon scattering processes governing SPhP decay. In particular, LSPhP antennas have attracted considerable interest for thermal management at the nanoscale, where the emission strongly diverts from the usual far-field blackbody radiation due to the presence of evanescent waves at the surface. However, far-field measurements cannot shed light on the behavior of antennas in the near-field region. To overcome this limitation, we employ scattering-scanning near-field optical microscopy (sSNOM) to unveil the spectral near-field response of 3C-SiC antenna arrays. We present a detailed description of the behavior of the antenna resonances by comparing far-field and near-field spectra and demonstrate the existence of a mode with no net dipole moment, absent in the far-field spectra, but of importance for applications that exploit the heightened electromagnetic near fields. Furthermore, we investigate the perturbation in the antenna response induced by the presence of the AFM tip, which can be further extended toward situations where for example strong IR emitters couple to LSPhP modes.},

keywords = {Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Determination of Nanoscale Mechanical Properties of Polymers via Plasmonic Nanoantennas},

author = {H D Boggiano and R Berte and A F Scarpettini and E Cortes and S A Maier and A V Bragas},

url = {\<Go to ISI\>://WOS:000542931300008},

doi = {10.1021/acsphotonics.0c00631},

issn = {2330-4022},

year  = {2020},

date = {2020-06-02},

journal = {Acs Photonics},

volume = {7},

number = {6},

pages = {1403-1409},

abstract = {Nanotechnology and the consequent emergence of miniaturized devices are driving the need to improve our understanding of the mechanical properties of a myriad of materials. Here we focus on amorphous polymeric materials and introduce a new way to determine the nanoscale mechanical response of polymeric thin films in the GHz range, using ultrafast optical means. Coupling of the films to plasmonic nanoantennas excited at their vibrational eigenfrequencies allows the extraction of the values of the mechanical moduli as well as the estimation of the glass transition temperature via time-domain measurements, here demonstrated for PMMA films. This nanoscale method can be extended to the determination of mechanical and elastic properties of a wide range of spatially strongly confined materials.},

keywords = {Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Atomic Layer Deposition Assisted Encapsulation of Quantum Dot Luminescent Microspheres toward Display Applications},

author = {F Fang and M J Liu and W Chen and H C Yang and Y Z Liu and X Li and J J Hao and B Xu and D Wu and K Cao and W Lei and P Muller-Buschbaum and X W Sun and R Chen and K Wang},

url = {\<Go to ISI\>://WOS:000528492300001},

doi = {10.1002/adom.201902118},

issn = {2195-1071},

year  = {2020},

date = {2020-06-01},

journal = {Advanced Optical Materials},

volume = {8},

number = {12},

abstract = {Quantum dots (QDs) are promising for being used in advanced displays due to their outstanding emission properties. Herein, a novel encapsulation method for QDs is reported and ultra-stable QDs@SiO2@Al2O3 luminescent microspheres (QLuMiS) are obtained by combining a sol-gel method for the intermediate SiO2 layer with a fluidized powder atomic layer deposition (ALD) for the outer Al2O3 layer. The rich hydroxyl coverage on the QDs@SiO2 surface provides abundant chemisorption sites, which are beneficial for the deposition of Al2O3 in the ALD process. Simultaneously, the water-oxygen channels in the SiO2 layer are blocked by the Al2O3 layer, which protects the QDs against deterioration. Consequently, the QLuMiS exhibit an excellent stability with 86% of the initial light conversion efficiency after 1000 h of blue light aging under a light power density of 2000 mW cm(-2). Such stability is significantly better than that of QDs@Al2O3 and QDs@SiO2 samples. Moreover, under this strong irradiation aging condition with blue light, the extrapolated lifetime (L50) of QLuMiS is 4969 h, which is ten times longer than that of QDs@SiO2 and is the best record as far as is known. Finally, a prototype of a QLuMiS-based cellphone screen with a wide color gamut of 115% NTSC is demonstrated.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Freestanding LiFe0.2Mn0.8PO4/rGO nanocomposites as high energy density fast charging cathodes for lithium-ion batteries},

author = {F Zoller and D B\"{o}hm and J Luxa and M D\"{o}blinger and Z Sofer and D Semenenko and T Bein and D Fattakhova-Rohlfing},

url = {https://www.sciencedirect.com/science/article/pii/S2468606920300356},

doi = {https://doi.org/10.1016/j.mtener.2020.100416},

issn = {2468-6069},

year  = {2020},

date = {2020-06-01},

journal = {Materials Today Energy},

volume = {16},

pages = {100416},

abstract = {Freestanding electrodes for lithium ion batteries are considered as a promising option to increase the total gravimetric energy density of the cells due to a decreased weight of electrochemically inactive materials. We report a simple procedure for the fabrication of freestanding LiFe0.2Mn0.8PO4 (LFMP)/rGO electrodes with a very high loading of active material of 83 wt%, high total loading of up to 8 mg cm−2, high energy density, excellent cycling stability and at the same time very fast charging rate, with a total performance significantly exceeding the values reported in the literature. The keys to the improved electrode performance are optimization of LFMP nanoparticles via nanoscaling and doping; the use of graphene oxide (GO) with its high concentration of surface functional groups favoring the adhesion of high amounts of LFMP nanoparticles, and freeze-casting of the GO-based nanocomposites to prevent the morphology collapse and provide a unique fluffy open microstructure of the freestanding electrodes. The rate and the cycling performance of the obtained freestanding electrodes are superior compared to their Al-foil coated equivalents, especially when calculated for the entire weight of the electrode, due to the extremely reduced content of electrochemically inactive material (17 wt% of electrochemically inactive material in case of the freestanding compared to 90 wt% for the Al-foil based electrode), resulting in 120 mAh g−1electrode in contrast to 10 mAh g−1electrode at 0.2 C. The electrochemical performance of the freestanding LFMP/rGO electrodes is also considerably better than the values reported in literature for freestanding LFMP and LMP composites, and can even keep up with those of LFP-based analogues. The freestanding LFMP/rGO reported in this work is additionally attractive due to its high gravimetric energy density (604 Wh kg−1LFMP at 0.2C). The obtained results demonstrate the advantage of freestanding LiFe0.2Mn0.8PO4/rGO electrodes and their great potential for applications in lithium ion batteries.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Transfer of Direct to Indirect Bound Excitons by Electron Intervalley Scattering in Cs2AgBiBr6 Double Perovskite Nanocrystals},

author = {A Dey and A F Richter and T Debnath and H Huang and L Polavarapu and J Feldmann},

url = {\<Go to ISI\>://WOS:000537682300069},

doi = {10.1021/acsnano.0c00997},

issn = {1936-0851},

year  = {2020},

date = {2020-05-26},

journal = {Acs Nano},

volume = {14},

number = {5},

pages = {5855-5861},

abstract = {Lead-free halide double perovskites have emerged as a nontoxic alternative to the heavily researched lead-based halide perovskites. However, their optical properties and the initial charge carrier relaxation processes are under debate. In this study, we apply time-resolved photoluminescence and differential transmission spectroscopy to investigate the photoexcited charge carrier dynamics within the indirect band structure of Cs2AgBiBr6 nanocrystals. Interestingly, we observe a high energetic emission stemming from the direct band gap, besides the previously reported emission from the indirect band gap transition. We attribute this emission to the radiative recombination of direct bound excitons. This emission maximum redshifts nearly 1 eV within 10 ps due to electron intervalley scattering, which leads to a transfer of direct to indirect bound excitons. We conclude that these direct bound excitons possess a giant oscillator strength causing not only a pronounced absorption peak at the optical band gap energy but also luminescence to occur at the direct band gap transition in spite of the prevailing intervalley scattering process. These results expand the understanding of the optical properties and the charge carrier relaxation in double perovskites, thus, facilitating the further development of optoelectronic devices harnessing lead-free perovskites.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Light-matter interaction in van der Waals hetero-structures},

author = {T Deilmann and M Rohlfing and U Wurstbauer},

url = {\<Go to ISI\>://WOS:000536663700001},

doi = {10.1088/1361-648X/ab8661},

issn = {0953-8984},

year  = {2020},

date = {2020-05-15},

urldate = {2020-05-15},

journal = {Journal of Physics-Condensed Matter},

volume = {32},

number = {33},

abstract = {Even if individual two-dimensional materials own various interesting and unexpected properties, the stacking of such layers leads to van der Waals solids which unite the characteristics of two dimensions with novel features originating from the interlayer interactions. In this topical review, we cover fabrication and characterization of van der Waals hetero-structures with a focus on hetero-bilayers made of monolayers of semiconducting transition metal dichalcogenides. Experimental and theoretical techniques to investigate those hetero-bilayers are introduced. Most recent findings focusing on different transition metal dichalcogenides hetero-structures are presented and possible optical transitions between different valleys, appearance of moire patterns and signatures of moire excitons are discussed. The fascinating and fast growing research on van der Waals hetero-bilayers provide promising insights required for their application as emerging quantum-nano materials.},

keywords = {Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Nonradiative Energy Transfer between Thickness-Controlled Halide Perovskite Nanoplatelets},

author = {A Singldinger and M Gramlich and C Gruber and C Lampe and A S Urban},

url = {\<Go to ISI\>://WOS:000535176100006},

doi = {10.1021/acsenergylett.0c00471},

issn = {2380-8195},

year  = {2020},

date = {2020-05-08},

journal = {Acs Energy Letters},

volume = {5},

number = {5},

pages = {1380-1385},

abstract = {Despite showing great promise for optoelectronics, the commercialization of halide perovskite nanostructure-based devices is hampered by inefficient electrical excitation and strong exciton binding energies. While transport of excitons in an energy-tailored system via Forster resonance energy transfer (FRET) could be an efficient alternative, halide ion migration makes the realization of cascaded structures difficult. Here, we show how these could be obtained by exploiting the pronounced quantum confinement effect in two-dimensional CsPbBr3-based nanoplatelets (NPls). In thin films of NPls of two predetermined thicknesses, we observe an enhanced acceptor photoluminescence (PL) emission and a decreased donor PL lifetime. This indicates a FRET-mediated process, benefitted by the structural parameters of the NPls. We determine corresponding transfer rates up to k(FRET) = 0.99 ns(-1) and efficiencies of nearly eta(FRET) = 70%. We also show FRET to occur between perovskite NPls of other thicknesses. Consequently, this strategy could lead to tailored energy cascade nanostructures for improved optoelectronic devices.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Colloidal PbS quantum dot stacking kinetics during deposition via printing},

author = {W Chen and H D Tang and N Li and M A Scheel and Y Xie and D P Li and V Korstgens and M Schwartzkopf and S V Roth and K Wang and X W Sun and P Muller-Buschbaum},

url = {\<Go to ISI\>://WOS:000531354100007},

doi = {10.1039/d0nh00008f},

issn = {2055-6756},

year  = {2020},

date = {2020-05-01},

journal = {Nanoscale Horizons},

volume = {5},

number = {5},

pages = {880-885},

abstract = {Colloidal PbS quantum dots (QDs) are attractive for solution-processed thin-film optoelectronic applications. In particular, directly achieving QD thin-films by printing is a very promising method for low-cost and large-scale fabrication. The kinetics of QD particles during the deposition process play an important role in the QD film quality and their respective optoelectronic performance. In this work, the particle self-organization behavior of small-sized QDs with an average diameter of 2.88 +/- 0.36 nm is investigated for the first time in situ during printing by grazing-incidence small-angle X-ray scattering (GISAXS). The time-dependent changes in peak intensities suggest that the structure formation and phase transition of QD films happen within 30 seconds. The stacking of QDs is initialized by a templating effect, and a face-centered cubic (FCC) film forms in which a superlattice distortion is also found. A body-centered cubic nested FCC stacking is the final QD assembly layout. The small size of the inorganic QDs and the ligand collapse during the solvent evaporation can well explain this stacking behavior. These results provide important fundamental understanding of structure formation of small-sized QD based films prepared via large-scale deposition with printing with a slot die coater.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Line-Scan Hyperspectral Imaging Microscopy with Linear Unmixing for Automated Two-Dimensional Crystals Identification},

author = {X Dong and A K Yetisen and H Tian and \.{I} G\"{u}ler and A V Stier and Z Li and M H K\"{o}hler and J Dong and M Jakobi and J J Finley and A W Koch},

url = {https://doi.org/10.1021/acsphotonics.0c00050},

doi = {10.1021/acsphotonics.0c00050},

year  = {2020},

date = {2020-04-23},

journal = {ACS Photonics},

volume = {7},

number = {5},

pages = {1216-1225},

abstract = {Two-dimensional (2D) materials exhibit unique optical properties when controlled to atomic thickness, and show large potential for applications in optoelectronics, photodetectors, and tunable excitonic devices. Current characterization techniques, including conventional optical microscopy, atomic force microscopy (AFM), and Raman spectroscopy are time-consuming and labor-intensive for studying large-scale samples. To realize the rapid identification of monolayer and few-layer crystals in the “haystack” of hundreds of flakes appearing in the exfoliation process, line-scan hyperspectral imaging microscopy combined with linear unmixing was developed to identify 2D molybdenum disulfide (MoS2) and hexagonal boron nitride (hBN) samples. A complete hyperspectral measurement and analysis, including single-band analysis, pixel-level spectral analysis and image classification was performed on MoS2 and hBN flakes with mono- and few-layer thickness. The characteristic spectra were extracted and analyzed via linear unmixing calculations to reconstruct the distribution images. The abundance maps showed the spatial distribution of these flakes with flake positions output, realizing an automatic identification of target flakes. This work shows a rapid and robust method for the determination of abundance maps of 2D flakes distributed over macroscopic areas.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Manganese-Doping-Induced Quantum Confinement within Host Perovskite Nanocrystals through Ruddlesden-Popper Defects},

author = {S Paul and E Bladt and A F Richter and M Doblinger and Y Tong and H Huang and A Dey and S Bals and T Debnath and L Polavarapu and J Feldmann},

url = {\<Go to ISI\>://WOS:000525279800024},

doi = {10.1002/anie.201914473},

issn = {1433-7851},

year  = {2020},

date = {2020-04-20},

journal = {Angewandte Chemie-International Edition},

volume = {59},

number = {17},

pages = {6794-6799},

abstract = {The concept of doping Mn2+ ions into II-VI semiconductor nanocrystals (NCs) was recently extended to perovskite NCs. To date, most studies on Mn2+ doped NCs focus on enhancing the emission related to the Mn2+ dopant via an energy transfer mechanism. Herein, we found that the doping of Mn2+ ions into CsPbCl3 NCs not only results in a Mn2+-related orange emission, but also strongly influences the excitonic properties of the host NCs. We observe for the first time that Mn2+ doping leads to the formation of RuddlesdenPopper (R.P.) defects and thus induces quantum confinement within the host NCs. We find that a slight doping with Mn2+ ions improves the size distribution of the NCs, which results in a prominent excitonic peak. However, with increasing the Mn2+ concentration, the number of R.P. planes increases leading to smaller single-crystal domains. The thus enhanced confinement and crystal inhomogeneity cause a gradual blue shift and broadening of the excitonic transition, respectively.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {In Situ Growth of All-Inorganic Perovskite Single Crystal Arrays on Electron Transport Layer},

author = {X Tang and W Chen and D Wu and A Gao and G Li and J Sun and K Yi and Z Wang and G Pang and H Yang and R Guo and H Liu and H Zhong and M Huang and R Chen and P M\"{u}ller-Buschbaum and X W Sun and K Wang},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/advs.201902767},

doi = {https://doi.org/10.1002/advs.201902767},

issn = {2198-3844},

year  = {2020},

date = {2020-04-12},

urldate = {2020-04-12},

journal = {Advanced Science},

volume = {7},

number = {11},

pages = {1902767},

abstract = {Abstract Directly growing perovskite single crystals on charge carrier transport layers will unravel a promising route for the development of emerging optoelectronic devices. Herein, in situ growth of high-quality all-inorganic perovskite (CsPbBr3) single crystal arrays (PeSCAs) on cubic zinc oxide (c-ZnO) is reported, which is used as an inorganic electron transport layer in optoelectronic devices, via a facile spin-coating method. The PeSCAs consist of rectangular thin microplatelets of 6\textendash10 µm in length and 2\textendash3 µm in width. The deposited c-ZnO enables the formation of phase-pure and highly crystallized cubic perovskites via an epitaxial lattice coherence of (100)CsPbBr3∥(100)c-ZnO, which is further confirmed by grazing incidence wide-angle X-ray scattering. The PeSCAs demonstrate a significant structural stability of 26 days with a 9 days excellent photoluminescence stability in ambient environment, which is much superior to the perovskite nanocrystals (PeNCs). The high crystallinity of the PeSCAs allows for a lower density of trap states, longer carrier lifetimes, and narrower energetic disorder for excitons, which leads to a faster diffusion rate than PeNCs. These results unravel the possibility of creating the interface toward c-ZnO heterogeneous layer, which is a major step for the realization of a better integration of perovskites and charge carrier transport layers.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Facet Control for Trap-State Suppression in Colloidal Quantum Dot Solids},

author = {Y Xia and W Chen and P Zhang and S Liu and K Wang and X Yang and H Tang and L Lian and J He and X Liu and G Liang and M Tan and L Gao and H Liu and H Song and D Zhang and J Gao and K Wang and X Lan and X Zhang and P M\"{u}ller-Buschbaum and J Tang and J Zhang},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adfm.202000594},

doi = {https://doi.org/10.1002/adfm.202000594},

issn = {1616-301X},

year  = {2020},

date = {2020-04-06},

journal = {Advanced Functional Materials},

volume = {30},

number = {22},

pages = {2000594},

abstract = {Abstract Trap states in colloidal quantum dot (QD) solids significantly affect the performance of QD solar cells, because they limit the open-circuit voltage and short circuit current. The 100 facets of PbS QDs are important origins of trap states due to their weak or missing passivation. However, previous investigations focused on synthesis, ligand exchange, or passivation approaches and ignored the control of 100 facets for a given dot size. Herein, trap states are suppressed from the source via facet control of PbS QDs. The 100 facets of ≈3 nm PbS QDs are minimized by tuning the balance between the growth kinetics and thermodynamics in the synthesis. The PbS QDs synthesized at a relatively low temperature with a high oversaturation follow a kinetics-dominated growth, producing nearly octahedral nanoparticles terminated mostly by 111 facets. In contrast, the PbS QDs synthesized at a relatively high temperature follow a thermodynamics-dominated growth. Thus, a spherical shape is preferred, producing truncated octahedral nanoparticles with more 100 facets. Compared to PbS QDs from thermodynamics-dominated growth, the PbS QDs with less 100 facets show fewer trap states in the QD solids, leading to a better photovoltaic device performance with a power conversion efficiency of 11.5%.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Phase Behavior and Substitution Limit of Mixed Cesium-Formamidinium Lead Triiodide Perovskites},

author = {B Charles and M T Weller and S Rieger and L E Hatcher and P F Henry and J Feldmann and D Wolverson and C C Wilson},

url = {\<Go to ISI\>://WOS:000526391300009},

doi = {10.1021/acs.chemmater.9b04032},

issn = {0897-4756},

year  = {2020},

date = {2020-03-24},

journal = {Chemistry of Materials},

volume = {32},

number = {6},

pages = {2282-2291},

abstract = {The mixed cation lead iodide perovskite photovoltaics show improved stability following site substitution of cesium ions (Cs+) onto the formamidinium cation sites (FA(+)) of (CH(NH2)(2)PbI3 (FAPbI(3)) and increased resistance to formation of the undesirable.-phase. The structural phase behavior of Cs(0.1)FA(0.9)PbI(3) has been investigated by neutron powder diffraction (NPD), complemented by single crystal and power X-ray diffraction and photoluminescence spectroscopy. The Cs-substitution limit has been determined to be less than 15%, and the cubic alpha-phase, Cs(0.1)FA(0.9)PbI(3), is shown to be synthesizable in bulk and stable at 300 K. On cooling the cubic Cs(0.1)FA(0.9)PbI(3), a slow, second-order cubic to tetragonal transition is observed close to 290 K, with variable temperature NPD indicating the presence of the tetragonal beta-phase, adopting the space group P4/mbm between 290 and 180 K. An orthorhombic phase or twinned tetragonal phase is formed below 180 K, and the temperature for further transition to a disordered state is lowered to 125 K compared to that seen in phase pure alpha-FAPbI(3) (140 K). These results demonstrate the importance of understanding the effect of cation site substitution on structure-property relationships in perovskite materials.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Formation of stable 2D methylammonium antimony iodide phase for lead-free perovskite-like solar cells*},

author = {N Giesbrecht and A Weis and T Bein},

url = {http://dx.doi.org/10.1088/2515-7655/ab78ef},

doi = {10.1088/2515-7655/ab78ef},

issn = {2515-7655},

year  = {2020},

date = {2020-03-20},

journal = {Journal of Physics: Energy},

volume = {2},

number = {2},

pages = {024007},

abstract = {The presence of lead in novel hybrid perovskite-based solar cells remains a significant issue regarding commercial applications. Therefore, antimony-based perovskite-like A3M2X9 structures are promising new candidates for low toxicity photovoltaic applications. So far, MA3Sb2I9 was reported to only crystallize in the ‘zero-dimensional’ (0D) dimer structure with wide indirect bandgap properties. However, the formation of the 2D layered polymorph is more suitable for solar cell applications due to its expected direct and narrow bandgap. Here, we demonstrate the first synthesis of phase pure 2D layered MA3Sb2I9, based on antimony acetate dissolved in alcoholic solvents. Using in situ XRD methods, we confirm the stability of the layered phase towards high temperature, but the exposure to 75% relative humidity for several hours leads to a rearrangement of the phase with partial formation of the 0D structure. We investigated the electronic band structure and confirmed experimentally the presence of a semi-direct bandgap at around 2.1 eV. Our work shows that careful control of nucleation via processing conditions can provide access to promising perovskite-like phases for photovoltaic applications.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Control of the orbital character of indirect excitons in MoS2/WS2 heterobilayers},

author = {J Kiemle and F Sigger and M Lorke and B Miller and K Watanabe and T Taniguchi and A W Holleitner and U Wurstbauer},

url = {https://link.aps.org/doi/10.1103/PhysRevB.101.121404},

doi = {10.1103/PhysRevB.101.121404},

year  = {2020},

date = {2020-03-18},

journal = {Physical Review B},

volume = {101},

number = {12},

pages = {121404},

keywords = {Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {How Certain Are the Reported Ionic Conductivities of Thiophosphate-Based Solid Electrolytes? An Interlaboratory Study},

author = {S Ohno and T Bernges and J Buchheim and M Duchardt and A-K Hatz and M A Kraft and H Kwak and A L Santhosha and Z Liu and N Minafra and F Tsuji and A Sakuda and R Schlem and S Xiong and Z Zhang and P Adelhelm and H Chen and A Hayashi and Y S Jung and B V Lotsch and B Roling and N M Vargas-Barbosa and W G Zeier},

url = {https://doi.org/10.1021/acsenergylett.9b02764},

doi = {10.1021/acsenergylett.9b02764},

year  = {2020},

date = {2020-03-13},

journal = {ACS Energy Letters},

volume = {5},

number = {3},

pages = {910-915},

keywords = {Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Mobile Small Polarons Qualitatively Explain Conductivity in Lithium Titanium Oxide Battery Electrodes},

author = {M Kick and C Grosu and M Schuderer and C Scheurer and H Oberhofer},

url = {\<Go to ISI\>://WOS:000526348400022},

doi = {10.1021/acs.jpclett.0c00568},

issn = {1948-7185},

year  = {2020},

date = {2020-03-12},

journal = {Journal of Physical Chemistry Letters},

volume = {11},

number = {7},

pages = {2535-2540},

abstract = {Lithium titanium oxide Li4Ti5O12 is an intriguing anode material promising particularly long-life batteries, due to its remarkable phase stability during (dis)charging of the cell. However, its usage is limited by its low intrinsic electronic conductivity. Introducing oxygen vacancies can be one method for overcoming this drawback, possibly by altering the charge carrier transport mechanism. We use Hubbard corrected density functional theory to show that polaronic states in combination with a possible hopping mechanism can play a crucial role in the experimentally observed increase in electronic conductivity. To gauge polaronic charge mobility, we compute the relative stabilities of different localization patterns and estimate polaron hopping barrier heights.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Sub-bandgap optical spectroscopy of epitaxial beta-Ga2O3 thin films},

author = {S J Hao and M Hetzl and V F Kunzelmann and S Matich and Q L Sai and C T Xia and I D Sharp and M Stutzmann},

url = {\<Go to ISI\>://WOS:000519225900001},

doi = {10.1063/1.5143393},

issn = {0003-6951},

year  = {2020},

date = {2020-03-02},

journal = {Applied Physics Letters},

volume = {116},

number = {9},

abstract = {Room temperature sub-gap optical absorption spectra measured by photothermal deflection spectroscopy were investigated for hetero- and homo-epitaxial beta-Ga2O3 layers grown by plasma-assisted molecular beam epitaxy as well as for a bulk crystal. The absorption spectra show a pronounced exponential Urbach tail with slope parameters of 120-150 meV in the spectral region between 4.5 and 5 eV, indicating an unusually large self-trapping energy of excitons. In addition, an absorption band related to deep defects is observed in the spectral region from 2.5 to 4.5 eV. The steepness of the Urbach tail as well as the strength of the defect-related absorption can be influenced and optimized by annealing at 900-1000 degrees C in an oxygen atmosphere. Similar features were also observed for bulk beta-Ga2O3 crystals and for homoepitaxial beta-Ga2O3 layers. The present results for beta-Ga2O3 are compared and discussed in the context of similar measurements for other wide-bandgap semiconductors of current interest in electronics and photocatalysis: GaN, ZnO, TiO2, and BiVO4.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Comparing the backfilling of mesoporous titania thin films with hole conductors of different sizes sharing the same mass density},

author = {R S Markl and N Hohn and E Hupf and L Biessmann and V Korstgens and L P Kreuzer and G Mangiapia and M Pomm and A Kriele and E Rivard and P Muller-Buschbaum},

url = {\<Go to ISI\>://WOS:000518799300015},

doi = {10.1107/s2052252520000913},

issn = {2052-2525},

year  = {2020},

date = {2020-03-01},

journal = {Iucrj},

volume = {7},

pages = {268-275},

abstract = {Efficient infiltration of a mesoporous titania matrix with conducting organic polymers or small molecules is one key challenge to overcome for hybrid photovoltaic devices. A quantitative analysis of the backfilling efficiency with time-of-flight grazing incidence small-angle neutron scattering (ToF-GISANS) and scanning electron microscopy (SEM) measurements is presented. Differences in the morphology due to the backfilling of mesoporous titania thin films are compared for the macromolecule poly[4,8-bis(5-(2-ethylhexyl)-thiophen-2-yl)benzo[1,2-b;4,5-b']dithiophene-2,6-diyl-alt-(4-(2-ethylhexyl)-3-fluorothieno[3,4-b]thiophene-)-2-carboxylate-2-6-diyl)] (PTB7-Th) and the heavy-element containing small molecule 2-pinacolboronate-3-phenylphenanthro[9,10-b]tellurophene(PhenTe-BPinPh). Hence, a 1.7 times higher backfilling efficiency of almost 70% is achieved for the small molecule PhenTe-BPinPh compared with the polymer PTB7-Th despite sharing the same volumetric mass density. The precise characterization of structural changes due to backfilling reveals that the volumetric density of backfilled materials plays a minor role in obtaining good backfilling efficiencies and interfaces with large surface contact.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Electron-Phonon Coupling in Current-Driven Single-Molecule Junctions},

author = {H Bi and C A Palma and Y X Gong and K Stallhofer and M Nuber and C Jing and F Meggendorfer and S Z Wen and C Y Yam and R Kienberger and M Elbing and M Mayor and H Iglev and J V Barth and J Reichert},

url = {\<Go to ISI\>://WOS:000515214000020},

doi = {10.1021/jacs.9b07757},

issn = {0002-7863},

year  = {2020},

date = {2020-02-19},

journal = {Journal of the American Chemical Society},

volume = {142},

number = {7},

pages = {3384-3391},

abstract = {Vibrational excitations provoked by coupling effects during charge transport through single molecules are intrinsic energy dissipation phenomena, in close analogy to electron-phonon coupling in solids. One fundamental challenge in molecular electronics is the quantitative determination of charge-vibrational (electron-phonon) coupling for single-molecule junctions. The ability to record electron-phonon coupling phenomena at the single-molecule level is a key prerequisite to fully rationalize and optimize charge-transport efficiencies for specific molecular configurations and currents. Here we exemplarily determine the pertaining coupling characteristics for a current-carrying chemically well-defined molecule by synchronous vibrational and current- voltage spectroscopy. These metal-molecule-metal junction insights are complemented by time-resolved infrared spectroscopy to assess the intramolecular vibrational relaxation dynamics. By measuring and analyzing the steady-state vibrational distribution during transient charge transport in a bis-phenylethynyl-anthracene derivative using anti-Stokes Raman scattering, we find similar to 0.5 vibrational excitations per elementary charge passing through the metal-moleculemetal junction, by means of a rate model ansatz and quantum-chemical calculations.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Finding the Right Blend: Interplay Between Structure and Sodium Ion Conductivity in the System Na5AlS4\textendashNa4SiS4},

author = {S Harm and A-K Hatz and C Schneider and C Hoefer and C Hoch and B V Lotsch},

url = {https://www.frontiersin.org/article/10.3389/fchem.2020.00090},

doi = {10.3389/fchem.2020.00090},

issn = {2296-2646},

year  = {2020},

date = {2020-02-18},

journal = {Frontiers in Chemistry},

volume = {8},

pages = {90},

abstract = {The rational design of high performance sodium solid electrolytes is one of the key challenges in modern battery research. In this work, we identify new sodium ion conductors in the substitution series Na_{5-x}Al_{1-x}Si_{x}S4 (0 ≤ x ≤ 1), which are entirely based on earth-abundant elements. These compounds exhibit conductivities ranging from 1.64 · 10^{−7} for Na_{4}SiS_{4} to 2.04 · 10^{−5} for Na_{8.5}(AlS_{4})_{0.5}(SiS_{4})_{1.5} (x = 0.75). We determined the crystal structures of the Na^{+}-ion conductors Na_{4}SiS_{4} as well as hitherto unknown Na_{5}AlS_{4} and Na_{9}(AlS_{4})(SiS_{4}). Na^{+}-ion conduction pathways were calculated by bond valence energy landscape (BVEL) calculations for all new structures highlighting the influence of the local coordination symmetry of sodium ions on the energy landscape within this family. Our findings show that the interplay of charge carrier concentration and low site symmetry of sodium ions can enhance the conductivity by several orders of magnitude.},

keywords = {Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {On-site tuning of the carrier lifetime in silicon for on-chip THz circuits using a focused beam of helium ions},

author = {P Zimmermann and A W Holleitner},

url = {https://doi.org/10.1063/1.5143421},

doi = {10.1063/1.5143421},

issn = {0003-6951},

year  = {2020},

date = {2020-02-18},

journal = {Applied Physics Letters},

volume = {116},

number = {7},

pages = {073501},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Nanoscale crystallization of a low band gap polymer in printed titania mesopores},

author = {N Li and L Song and N Hohn and S Saxena and W Cao and X Y Jiang and P Muller-Buschbaum},

url = {\<Go to ISI\>://WOS:000515391000053},

doi = {10.1039/c9nr08055d},

issn = {2040-3364},

year  = {2020},

date = {2020-02-14},

journal = {Nanoscale},

volume = {12},

number = {6},

pages = {4085-4093},

abstract = {The crystallization behavior of the low band gap polymer poly[(5,6-difluoro-2,1,3-benzothiadiazol-4,7-diyl)-alt-(3,3 '''-di(2-octyldodecyl)2,2 ';5 ',2 '';5 '',2 '''-quaterthiophen-5,5 '''-diyl)] (PffBT4T-2OD) induced in printed mesoporous titania films with different pore sizes is studied to optimize the crystal orientation for an application in hybrid solar cells. The correlation between the crystal structure of PffBT4T-2OD and the titania pore size is investigated with a combination of grazing incidence wide-angle X-ray scattering (GIWAXS) and grazing incidence small-angle X-ray scattering (GISAXS). For comparison, poly(3-hexylthiophene) (P3HT) is also backfilled into the same four types of printed titania mesoporous scaffolds. Both, lattice constants and crystal sizes of edge-on oriented P3HT crystals decrease with increasing the titania pore size. Similarly and irrespective of the crystal orientation, a denser stacking of PffBT4T-2OD chains is found for larger pore sizes of the titania matrix. For an edge-on orientation, also bigger PffBT4T-2OD crystals are favorably formed in smaller pores, whereas for a face-on orientation, PffBT4T-2OD crystals increase with increasing size of the titania pores. Thus, the best ratio of face-on to edge-on crystals for PffBT4T-2OD is obtained through infiltration into large titania pores.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Key Factors for Template-Oriented Porous Titania Synthesis: Solvents and Catalysts},

author = {S S Yin and L Song and S L Xia and Y J Cheng and N Hohn and W Chen and K Wang and W Cao and S J Hou and P Muller-Buschbaum},

url = {\<Go to ISI\>://WOS:000507321300001},

doi = {10.1002/smtd.201900689},

issn = {2366-9608},

year  = {2020},

date = {2020-01-15},

journal = {Small Methods},

keywords = {Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Operando Identification of Liquid Intermediates in Lithium\textendashSulfur Batteries via Transmission UV\textendashvis Spectroscopy},

author = {Q He and A T S Freiberg and M U M Patel and S Qian and H A Gasteiger},

url = {http://dx.doi.org/10.1149/1945-7111/ab8645},

doi = {10.1149/1945-7111/ab8645},

issn = {0013-4651 1945-7111},

year  = {2020},

date = {2020-01-05},

urldate = {2020-01-05},

journal = {Journal of The Electrochemical Society},

volume = {167},

number = {8},

pages = {080508},

abstract = {Lithium-sulfur (Li-S) batteries are facing various challenges with regards to performance and durability, and further improvements require a better understanding of the fundamental working mechanisms, including an identification of the reaction intermediates in an operating Li-S battery. In this study, we present an operando transmission UV\textendashvis spectro-electrochemical cell design that employs a conventional sulfur/carbon composite electrode, propose a comprehensive peak assignment for polysulfides in DOL:DME-based electrolyte, and finally identify the liquid intermediates in the discharging process of an operating Li-S cell. Here, we propose for the first time a meta-stable polysulfide species (S32−) that is present at substantial concentrations during the 2nd discharge plateau in a Li-S battery. We identify the S32− species that are the reduction product of S42−, as deducted from the analysis of the obtained operando UV\textendashvis spectra along with the transferred charge, and confirmed by rotating ring disk electrode measurements for the reduction of a solution with a nominal Li2S4 stoichiometry. Furthermore, our operando results provide insight into the potential-dependent stability of different S-species and the rate-limiting (electro)chemical steps during discharging. Finally, we propose a viable reaction pathway of how S8 is electrochemically reduced to Li2S2/Li2S based on our operando results as well as that reported in the literature.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Scalable single-photon sources in atomically thin MoS2},

author = {J Klein and L Sigl and A H\"{o}tger and S Gyger and K Barthelmi and M Florian and A Kerelsky and E Mitterreiter and C Kastl and S Rey and T Taniguchi and K Watanabe and F Jahnke and V Zwiller and K J\"{o}ns and A Pasupathy and F Ross and K M\"{u}ller and U Wurstbauer and J J Finley and A W Holleitner},

url = {https://doi.org/10.1117/12.2570472},

doi = {10.1117/12.2570472},

year  = {2020},

date = {2020-01-01},

urldate = {2020-01-01},

volume = {11471},

publisher = {SPIE},

series = {SPIE Nanoscience + Engineering},

abstract = {2D materials offer a wide range of perspectives for hosting highly localized 0D states, e.g. vacancy defects, that offer great potential for integrated quantum photonic applications. Here, we create individual defects that act as our single-photon emitters by highly local He-ion irradiation in a monolayer MoS2 van der Waals heterostructure. The defects show anti-bunched light emission at a characteristic energy of ~ 1.75 eV. The emission is highly homogeneous and background free due to the hBN encapsulation with a creation yield of \> 70%. Spectroscopic investigation of individual single-photon emitters reveals a strongly asymmetric line shape resembling interaction with acoustic phonons in excellent agreement with an independent boson model. Moreover, emitters are spatially integrated and electrically controlled in field-switchable van der Waals devices. Our work firmly establishes 2D materials as a highly scalable material platform for integrated quantum photonics.},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Excitons and narrow bands determine the optical properties of cesium bismuth halides},

author = {S Rieger and B J Bohn and M Doblinger and A F Richter and Y Tong and K Wang and P Muller-Buschbaum and L Polavarapu and L Leppert and J K Stolarczyk and J Feldmann},

url = {\<Go to ISI\>://WOS:000498055800001},

doi = {10.1103/PhysRevB.100.201404},

issn = {2469-9950},

year  = {2019},

date = {2019-11-20},

journal = {Physical Review B},

volume = {100},

number = {20},

keywords = {Foundry Inorganic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Effect of Solvent Additives on the Morphology and Device Performance of Printed Nonfullerene Acceptor Based Organic Solar Cells},

author = {K S Wienhold and V K\"{o}rstgens and S Grott and X Jiang and M Schwartzkopf and S V Roth and P M\"{u}ller-Buschbaum},

url = {https://doi.org/10.1021/acsami.9b16784},

doi = {10.1021/acsami.9b16784},

issn = {1944-8244},

year  = {2019},

date = {2019-11-13},

journal = {ACS Applied Materials \& Interfaces},

volume = {11},

number = {45},

pages = {42313-42321},

abstract = {Printing of active layers of high-efficiency organic solar cells and morphology control by processing with varying solvent additive concentrations are important to realize real-world use of bulk-heterojunction photovoltaics as it enables both up-scaling and optimization of the device performance. In this work, active layers of the conjugated polymer with benzodithiophene units PBDB-T-SF and the nonfullerene small molecule acceptor IT-4F are printed using meniscus guided slot-die coating. 1,8-Diiodooctane (DIO) is added to optimize the power conversion efficiency (PCE). The effect on the inner nanostructure and surface morphology of the material is studied for different solvent additive concentrations with grazing incidence small-angle X-ray scattering (GISAXS), grazing incidence wide-angle X-ray scattering (GIWAXS), scanning electron microscopy (SEM), and atomic force microscopy (AFM). Optical properties are studied with photoluminescence (PL), UV/vis absorption spectroscopy, and external quantum efficiency (EQE) measurements and correlated to the corresponding PCEs. The addition of 0.25 vol % DIO enhances the average PCE from 3.5 to 7.9%, whereas at higher concentrations the positive effect is less pronounced. A solar cell performance of 8.95% is obtained for the best printed device processed with an optimum solvent additive concentration. Thus, with the large-scale preparation method printing similarly well working solar cells can be realized as with the spin-coating method.},

keywords = {Foundry Organic, Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Real-Time Electron and Hole Transport Dynamics in Halide Perovskite Nanowires},

author = {L Janker and Y Tong and L Polavarapu and J Feldmann and A S Urban and H J Krenner},

url = {\<Go to ISI\>://WOS:000502687500044},

doi = {10.1021/acs.nanolett.9b03396},

issn = {1530-6984},

year  = {2019},

date = {2019-10-30},

journal = {Nano Letters},

volume = {19},

number = {12},

pages = {8701-8707},

keywords = {Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Particle-in-a-Frame Nanostructures with Interior Nanogaps},

author = {S Lee and J Kim and H Yang and E Cort\'{e}s and S Kang and S W Han},

url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.201908291},

doi = {https://doi.org/10.1002/anie.201908291},

issn = {1433-7851},

year  = {2019},

date = {2019-09-03},

journal = {Angewandte Chemie International Edition},

volume = {58},

number = {44},

pages = {15890-15894},

abstract = {Abstract Designing plasmonic hollow colloids with small interior nanogaps would allow structural properties to be exploited that are normally linked to an ensemble of particles but within a single nanoparticle. Now, a synthetic approach for constructing a new class of frame nanostructures is presented. Fine control over the galvanic replacement reaction of Ag nanoprisms with Au precursors gave unprecedented Au particle-in-a-frame nanostructures with well-defined sub-2 nm interior nanogaps. The prepared nanostructures exhibited superior performance in applications, such as plasmonic sensing and surface-enhanced Raman scattering, over their solid nanostructure and nanoframe counterparts. This highlights the benefit of their interior hot spots, which can highly promote and maximize the electric field confinement within a single nanostructure.},

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

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Ultrafast All-Optical Modulation in 2D Hybrid Perovskites},

author = {G Grinblat and I Abdelwahab and M P Nielsen and P Dichtl and K Leng and R F Oulton and K P Loh and S A Maier},

url = {https://doi.org/10.1021/acsnano.9b04483},

doi = {10.1021/acsnano.9b04483},

issn = {1936-0851},

year  = {2019},

date = {2019-08-27},

journal = {ACS Nano},

volume = {13},

number = {8},

pages = {9504-9510},

keywords = {Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Spontaneous Crystallization of Perovskite Nanocrystals in Nonpolar Organic Solvents: A Versatile Approach for their Shape-controlled Synthesis},

author = {L Polavarapu and H Huang and Y Li and Y Tong and E-P Yao and M D\"{o}blinger and M W Feil and A F Richter and A L Rogach and J Feldmann},

url = {https://doi.org/10.1002/anie.201906862},

doi = {10.1002/anie.201906862},

issn = {1433-7851},

year  = {2019},

date = {2019-08-21},

journal = {Angewandte Chemie International Edition},

volume = {0},

number = {ja},

abstract = {The growing demand of perovskite nanocrystals (NCs) for various applications has stimulated great research interest in the development of facile synthetic methods. They have often been synthesized by either ligand assisted reprecipitation (LARP) at room temperature or by hot-injection at high temperatures and inert atmosphere. However, the use of polar solvents in LARP effects their stability. Herein, we report on the spontaneous crystallization of perovskite nanocrystals in nonpolar organic media at ambient conditions by simple mixing of precursor-ligand complexes without applying any external stimuli. The shape of the NCs can be controlled from nanocubes to nanoplatelets by varying the ratio of monovalent (e.g. formamidinium+ (FA+) and Cs+) to divalent (Pb2+) cation-ligand complexes. The precursor-ligand complexes are stable for months, and thus perovskite NCs can be readily prepared prior to use.  Moreover, we show that this versatile synthetic process is scalable and can be generally applicable for perovskite NCs of different compositions.},

keywords = {Solid-Solid},

pubstate = {published},

tppubtype = {article}

}

@article{,

title = {Nonlinear Pancharatnam−Berry Phase Metasurfaces beyond the Dipole Approximation},

author = {S D Gennaro and Y Li and S A Maier and R F Oulton},

url = {https://doi.org/10.1021/acsphotonics.9b00877},

doi = {10.1021/acsphotonics.9b00877},

year  = {2019},

date = {2019-08-12},

journal = {ACS Photonics},

keywords = {Solid-Solid},

pubstate = {published},

tppubtype = {article}

}