S Strohmair, A Dey, Y Tong, L Polavarapu, B J Bohn, J Feldmann
Spin Polarization Dynamics of Free Charge Carriers in CsPbI3 Nanocrystals Journal Article
In: Nano Letters, vol. 20, no. 7, pp. 4724-4730, 2020, ISSN: 1530-6984.
Abstract | Links | Tags: Foundry Inorganic
@article{,
title = {Spin Polarization Dynamics of Free Charge Carriers in CsPbI3 Nanocrystals},
author = {S Strohmair and A Dey and Y Tong and L Polavarapu and B J Bohn and J Feldmann},
url = {\<Go to ISI\>://WOS:000548893200004},
doi = {10.1021/acs.nanolett.9b05325},
issn = {1530-6984},
year = {2020},
date = {2020-07-08},
journal = {Nano Letters},
volume = {20},
number = {7},
pages = {4724-4730},
abstract = {Lead halide perovskites (LHPs) exhibit large spin-orbit coupling (SOC), leading to only twofold-degenerate valence and conduction bands and therefore allowing for efficient optical orientation. This makes them ideal materials to study charge carrier spins. With this study we elucidate the spin dynamics of photoexcited charge carriers and the underlying spin relaxation mechanisms in CsPbI3 nanocrystals by employing time-resolved differential transmission spectroscopy (DTS). We find that the photoinduced spin polarization significantly diminishes during thermalization and cooling toward the energetically favorable band edge. Temperature-dependent DTS reveals a decay in spin polarization that is more than 1 order of magnitude faster at room temperature (3 ps) than at cryogenic temperatures (32 ps). We propose that spin relaxation of free charge carriers in large-SOC materials like LHPs occurs as a result of carrier-phonon scattering, as described by the Elliott-Yafet mechanism.},
keywords = {Foundry Inorganic},
pubstate = {published},
tppubtype = {article}
}
Al M F Fattah, M R Amin, M Mallmann, S Kasap, W Schnick, A Moewes
Electronic structure investigation of wide band gap semiconductors—Mg2PN3 and Zn2PN3: experiment and theory Journal Article
In: Journal of Physics: Condensed Matter, vol. 32, no. 40, pp. 405504, 2020, ISSN: 0953-8984 1361-648X.
Abstract | Links | Tags: Foundry Inorganic, Solid-Solid
@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}
}
R Guo, A Buyruk, X Jiang, W Chen, L K Reb, M A Scheel, T Ameri, P Müller-Buschbaum
Tailoring the orientation of perovskite crystals via adding two-dimensional polymorphs for perovskite solar cells Journal Article
In: Journal of Physics: Energy, vol. 2, no. 3, pp. 034005, 2020, ISSN: 2515-7655.
Abstract | Links | Tags: Foundry Inorganic, Solid-Solid
@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}
}
C X Liu, S A Maier, G X Li
Genetic-Algorithm-Aided Meta-Atom Multiplication for Improved Absorption and Coloration in Nanophotonics Journal Article
In: Acs Photonics, vol. 7, no. 7, pp. 1716-1722, 2020, ISSN: 2330-4022.
Abstract | Links | Tags: Foundry Inorganic, Solid-Solid
@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}
}
M Gramlich, B J Bohn, Y Tong, L Polavarapu, J Feldmann, A S Urban
Thickness-Dependence of Exciton-Exciton Annihilation in Halide Perovskite Nanoplatelets Journal Article
In: Journal of Physical Chemistry Letters, vol. 11, no. 13, pp. 5361-5366, 2020, ISSN: 1948-7185.
Abstract | Links | Tags: Foundry Inorganic, Solid-Solid
@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}
}
E Mitterreiter, B Schuler, K A Cochrane, U Wurstbauer, A Weber-Bargioni, C Kastl, A W Holleitner
Atomistic Positioning of Defects in Helium Ion Treated Single-Layer MoS2 Journal Article
In: Nano Letters, vol. 20, no. 6, pp. 4437-4444, 2020, ISSN: 1530-6984.
Abstract | Links | Tags: Foundry Inorganic
@article{,
title = {Atomistic Positioning of Defects in Helium Ion Treated Single-Layer MoS2},
author = {E Mitterreiter and B Schuler and K A Cochrane and U Wurstbauer and A Weber-Bargioni and C Kastl and A W Holleitner},
url = {\<Go to ISI\>://WOS:000541691200049},
doi = {10.1021/acs.nanolett.0c01222},
issn = {1530-6984},
year = {2020},
date = {2020-06-10},
journal = {Nano Letters},
volume = {20},
number = {6},
pages = {4437-4444},
abstract = {Structuring materials with atomic precision is the ultimate goal of nanotechnology and is becoming increasingly relevant as an enabling technology for quantum electronics/spintronics and quantum photonics. Here, we create atomic defects in monolayer MoS2 by helium ion (He-ion) beam lithography with a spatial fidelity approaching the single-atom limit in all three dimensions. Using low-temperature scanning tunneling microscopy (STM), we confirm the formation of individual point defects in MoS2 upon He-ion bombardment and show that defects are generated within 9 nm of the incident helium ions. Atom-specific sputtering yields are determined by analyzing the type and occurrence of defects observed in high-resolution STM images and compared with with Monte Carlo simulations. Both theory and experiment indicate that the He-ion bombardment predominantly generates sulfur vacancies.},
keywords = {Foundry Inorganic},
pubstate = {published},
tppubtype = {article}
}
T Lochner, M Perchthaler, J T Binder, J P Sabawa, T A Dao, A S Bandarenka
Real-Time Impedance Analysis for the On-Road Monitoring of Automotive Fuel Cells Journal Article
In: ChemElectroChem, vol. 7, no. 13, pp. 2784-2791, 2020, ISSN: 2196-0216.
Abstract | Links | Tags: Foundry Inorganic
@article{nokey,
title = {Real-Time Impedance Analysis for the On-Road Monitoring of Automotive Fuel Cells},
author = {T Lochner and M Perchthaler and J T Binder and J P Sabawa and T A Dao and A S Bandarenka},
url = {https://chemistry-europe.onlinelibrary.wiley.com/doi/abs/10.1002/celc.202000510},
doi = {https://doi.org/10.1002/celc.202000510},
issn = {2196-0216},
year = {2020},
date = {2020-06-09},
journal = {ChemElectroChem},
volume = {7},
number = {13},
pages = {2784-2791},
abstract = {Abstract The on-road monitoring of polymer electrolyte membrane fuel cells (PEMFCs) in automotive systems optimizes their efficiency and fuel consumption in addition to increasing their lifetime. In this work, electrochemical impedance spectroscopy (EIS) measurements and special EIS data analysis algorithms were used to quickly identify fuel cell operational modes and failures during cell operation. The approach developed enables the measurement and analysis time of only a few seconds and allows the accurate extraction of information about the membrane and charge transfer resistance. The data analysis procedures show similar accuracy to that of the complex non-linear least square fitting algorithms. As a result, typical operational failures like air and hydrogen starvation were able to be easily distinguished, and different operational states (membrane humidification, air stoichiometry) of the PEMFCs could be identified.},
keywords = {Foundry Inorganic},
pubstate = {published},
tppubtype = {article}
}
F Fang, M J Liu, W Chen, H C Yang, Y Z Liu, X Li, J J Hao, B Xu, D Wu, K Cao, W Lei, P Muller-Buschbaum, X W Sun, R Chen, K Wang
Atomic Layer Deposition Assisted Encapsulation of Quantum Dot Luminescent Microspheres toward Display Applications Journal Article
In: Advanced Optical Materials, vol. 8, no. 12, 2020, ISSN: 2195-1071.
Abstract | Links | Tags: Foundry Inorganic, Solid-Solid
@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}
}
F Zoller, D Böhm, J Luxa, M Döblinger, Z Sofer, D Semenenko, T Bein, D Fattakhova-Rohlfing
Freestanding LiFe0.2Mn0.8PO4/rGO nanocomposites as high energy density fast charging cathodes for lithium-ion batteries Journal Article
In: Materials Today Energy, vol. 16, pp. 100416, 2020, ISSN: 2468-6069.
Abstract | Links | Tags: Foundry Inorganic, Solid-Solid
@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}
}
A Dey, A F Richter, T Debnath, H Huang, L Polavarapu, J Feldmann
Transfer of Direct to Indirect Bound Excitons by Electron Intervalley Scattering in Cs2AgBiBr6 Double Perovskite Nanocrystals Journal Article
In: Acs Nano, vol. 14, no. 5, pp. 5855-5861, 2020, ISSN: 1936-0851.
Abstract | Links | Tags: Foundry Inorganic, Solid-Solid
@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}
}
B Garlyyev, S Xue, J Fichtner, A S Bandarenka, C Andronescu
Prospects of Value-Added Chemicals and Hydrogen via Electrolysis Journal Article
In: Chemsuschem, vol. 13, no. 10, pp. 2513-2521, 2020, ISSN: 1864-5631.
Abstract | Links | Tags: Foundry Inorganic, Solid-Liquid
@article{,
title = {Prospects of Value-Added Chemicals and Hydrogen via Electrolysis},
author = {B Garlyyev and S Xue and J Fichtner and A S Bandarenka and C Andronescu},
url = {\<Go to ISI\>://WOS:000520259100001},
doi = {10.1002/cssc.202000339},
issn = {1864-5631},
year = {2020},
date = {2020-05-22},
journal = {Chemsuschem},
volume = {13},
number = {10},
pages = {2513-2521},
abstract = {Cost is a major drawback that limits the industrial-scale hydrogen production through water electrolysis. The overall cost of this technology can be decreased by coupling the electrosynthesis of value-added chemicals at the anode side with electrolytic hydrogen generation at the cathode. This Minireview provides a directory of anodic oxidation reactions that can be combined with cathodic hydrogen generation. The important parameters for selecting the anodic reactions, such as choice of catalyst material and its selectivity towards specific products are elaborated in detail. Furthermore, various novel electrolysis cell architectures for effortless separation of value-added products from hydrogen gas are described.},
keywords = {Foundry Inorganic, Solid-Liquid},
pubstate = {published},
tppubtype = {article}
}
S Xue, B Garlyyev, A Auer, J Kunze-Liebhauser, A S Bandarenka
How the Nature of the Alkali Metal Cations Influences the Double-Layer Capacitance of Cu, Au, and Pt Single-Crystal Electrodes Journal Article
In: Journal of Physical Chemistry C, vol. 124, no. 23, pp. 12442-12447, 2020, ISSN: 1932-7447.
Abstract | Links | Tags: Foundry Inorganic, Solid-Liquid
@article{,
title = {How the Nature of the Alkali Metal Cations Influences the Double-Layer Capacitance of Cu, Au, and Pt Single-Crystal Electrodes},
author = {S Xue and B Garlyyev and A Auer and J Kunze-Liebhauser and A S Bandarenka},
url = {\<Go to ISI\>://WOS:000541745800029},
doi = {10.1021/acs.jpcc.0c01715},
issn = {1932-7447},
year = {2020},
date = {2020-05-09},
journal = {Journal of Physical Chemistry C},
volume = {124},
number = {23},
pages = {12442-12447},
abstract = {In this work, we have investigated the influence of alkali metal cations on the electrical double-layer (EDL) properties for various metal electrodes. Using electrochemical impedance spectroscopy, we demonstrate that those cations significantly affect the EDL capacitance in the case of single-crystalline Cu(111), Cu(100), Au(111), Pt(111), stepped Pt(775), and kinked Pt(12 10 5) electrodes in 0.05 M MeClO4 (Me+ = Li+, Na+, K+, Rb+, and Cs+) electrolytes. For all the electrodes, the capacitance always linearly increases with decreasing hydration energy of Me+ in the following order: Li+ \< Na+ \< K+ \< Rb+ \< Cs+. Moreover, we estimate the effective concentrations of the alkali metal cations near the electrode surfaces by correlating the capacitances with the relative permittivity. For all the electrodes, the concentrations near the electrode surface were calculated to be similar to 60 to 80 times higher than in the bulk solutions.},
keywords = {Foundry Inorganic, Solid-Liquid},
pubstate = {published},
tppubtype = {article}
}
A Singldinger, M Gramlich, C Gruber, C Lampe, A S Urban
Nonradiative Energy Transfer between Thickness-Controlled Halide Perovskite Nanoplatelets Journal Article
In: Acs Energy Letters, vol. 5, no. 5, pp. 1380-1385, 2020, ISSN: 2380-8195.
Abstract | Links | Tags: Foundry Inorganic, Solid-Solid
@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}
}
L D M Peters, J Kussmann, C Ochsenfeld
In: The Journal of Physical Chemistry Letters, vol. 11, no. 10, pp. 3955-3961, 2020.
Abstract | Links | Tags: Foundry Inorganic
@article{nokey,
title = {Combining Graphics Processing Units, Simplified Time-Dependent Density Functional Theory, and Finite-Difference Couplings to Accelerate Nonadiabatic Molecular Dynamics},
author = {L D M Peters and J Kussmann and C Ochsenfeld},
url = {https://doi.org/10.1021/acs.jpclett.0c00320},
doi = {10.1021/acs.jpclett.0c00320},
year = {2020},
date = {2020-05-06},
journal = {The Journal of Physical Chemistry Letters},
volume = {11},
number = {10},
pages = {3955-3961},
abstract = {Starting from our recently published implementation of nonadiabatic molecular dynamics (NAMD) on graphics processing units (GPUs), we explore further approaches to accelerate ab initio NAMD calculations at the time-dependent density functional theory (TDDFT) level of theory. We employ (1) the simplified TDDFT schemes of Grimme et al. and (2) the Hammes-Schiffer\textendashTully approach to obtain nonadiabatic couplings from finite-difference calculations. The resulting scheme delivers an accurate physical picture while virtually eliminating the two computationally most demanding steps of the algorithm. Combined with our GPU-based integral routines for SCF, TDDFT, and TDDFT derivative calculations, NAMD simulations of systems of a few hundreds of atoms at a reasonable time scale become accessible on a single compute node. To demonstrate this and to present a first, illustrative example, we perform TDDFT/MM-NAMD simulations of the rhodopsin protein.},
keywords = {Foundry Inorganic},
pubstate = {published},
tppubtype = {article}
}
W Chen, H D Tang, N Li, M A Scheel, Y Xie, D P Li, V Korstgens, M Schwartzkopf, S V Roth, K Wang, X W Sun, P Muller-Buschbaum
Colloidal PbS quantum dot stacking kinetics during deposition via printing Journal Article
In: Nanoscale Horizons, vol. 5, no. 5, pp. 880-885, 2020, ISSN: 2055-6756.
Abstract | Links | Tags: Foundry Inorganic, Solid-Solid
@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}
}
X Dong, A K Yetisen, H Tian, İ Güler, A V Stier, Z Li, M H Köhler, J Dong, M Jakobi, J J Finley, A W Koch
Line-Scan Hyperspectral Imaging Microscopy with Linear Unmixing for Automated Two-Dimensional Crystals Identification Journal Article
In: ACS Photonics, vol. 7, no. 5, pp. 1216-1225, 2020.
Abstract | Links | Tags: Foundry Inorganic, Solid-Solid
@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}
}
T L Maier, M Golibrzuch, S Mendisch, W Schindler, M Becherer, K Krischer
Lateral silicon oxide/gold interfaces enhance the rate of electrochemical hydrogen evolution reaction in alkaline media Journal Article
In: Journal of Chemical Physics, vol. 152, no. 15, 2020, ISSN: 0021-9606.
Abstract | Links | Tags: Foundry Inorganic, Solid-Liquid
@article{,
title = {Lateral silicon oxide/gold interfaces enhance the rate of electrochemical hydrogen evolution reaction in alkaline media},
author = {T L Maier and M Golibrzuch and S Mendisch and W Schindler and M Becherer and K Krischer},
url = {\<Go to ISI\>://WOS:000529243500002},
doi = {10.1063/5.0003295},
issn = {0021-9606},
year = {2020},
date = {2020-04-21},
journal = {Journal of Chemical Physics},
volume = {152},
number = {15},
abstract = {The production of solar hydrogen with a silicon based water splitting device is a promising future technology, and silicon-based metal-insulator-semiconductor (MIS) electrodes have been proposed as suitable architectures for efficient photocathodes based on the electronic properties of the MIS structures and the catalytic properties of the metals. In this paper, we demonstrate that the interfaces between the metal and oxide of laterally patterned MIS electrodes may strongly enhance the catalytic activity of the electrode compared to bulk metal surfaces. The employed electrodes consist of well-defined, large-area arrays of gold structures of various mesoscopic sizes embedded in a silicon oxide support on silicon. We demonstrate that the activity of these electrodes for hydrogen evolution reaction (HER) increases with an increase in gold/silicon oxide boundary length in both acidic and alkaline media, although the enhancement of the HER rate in alkaline electrolytes is considerably larger than in acidic electrolytes. Electrodes with the largest interfacial length of gold/silicon oxide exhibited a 10-times larger HER rate in alkaline electrolytes than those with the smallest interfacial length. The data suggest that at the metal/silicon oxide boundaries, alkaline HER is enhanced through a bifunctional mechanism, which we tentatively relate to the laterally structured electrode geometry and to positive charges present in silicon oxide: Both properties change locally the interfacial electric field at the gold/silicon oxide boundary, which, in turn, facilitates a faster transport of hydroxide ions away from the electrode/electrolyte interface in alkaline solution. This mechanism boosts the alkaline HER activity of p-type silicon based photoelectrodes close to their HER activity in acidic electrolytes.},
keywords = {Foundry Inorganic, Solid-Liquid},
pubstate = {published},
tppubtype = {article}
}
S Paul, E Bladt, A F Richter, M Doblinger, Y Tong, H Huang, A Dey, S Bals, T Debnath, L Polavarapu, J Feldmann
Manganese-Doping-Induced Quantum Confinement within Host Perovskite Nanocrystals through Ruddlesden-Popper Defects Journal Article
In: Angewandte Chemie-International Edition, vol. 59, no. 17, pp. 6794-6799, 2020, ISSN: 1433-7851.
Abstract | Links | Tags: Foundry Inorganic, Solid-Solid
@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}
}
A Dey, A F Richter, T Debnath, H Huang, L Polavarapu, J Feldmann
Transfer of Direct to Indirect Bound Excitons by Electron Intervalley Scattering in Cs2AgBiBr6 Double Perovskite Nanocrystals Journal Article
In: ACS Nano, vol. 14, no. 5, pp. 5855-5861, 2020, ISSN: 1936-0851.
Abstract | Links | Tags: Foundry Inorganic, Molecularly-Functionalized
@article{nokey,
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 = {https://doi.org/10.1021/acsnano.0c00997},
doi = {10.1021/acsnano.0c00997},
issn = {1936-0851},
year = {2020},
date = {2020-04-16},
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, Molecularly-Functionalized},
pubstate = {published},
tppubtype = {article}
}
X Tang, W Chen, D Wu, A Gao, G Li, J Sun, K Yi, Z Wang, G Pang, H Yang, R Guo, H Liu, H Zhong, M Huang, R Chen, P Müller-Buschbaum, X W Sun, K Wang
In Situ Growth of All-Inorganic Perovskite Single Crystal Arrays on Electron Transport Layer Journal Article
In: Advanced Science, vol. 7, no. 11, pp. 1902767, 2020, ISSN: 2198-3844.
Abstract | Links | Tags: Foundry Inorganic, Solid-Solid
@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}
}
M Kraut, E Sirotti, F Pantle, C M Jiang, G Grotzner, M Koch, L I Wagner, I D Sharp, M Stutzmann
Control of Band Gap and Band Edge Positions in Gallium-Zinc Oxynitride Grown by Molecular Beam Epitaxy Journal Article
In: Journal of Physical Chemistry C, vol. 124, no. 14, pp. 7668-7676, 2020, ISSN: 1932-7447.
Abstract | Links | Tags: Foundry Inorganic, Solid-Liquid
@article{,
title = {Control of Band Gap and Band Edge Positions in Gallium-Zinc Oxynitride Grown by Molecular Beam Epitaxy},
author = {M Kraut and E Sirotti and F Pantle and C M Jiang and G Grotzner and M Koch and L I Wagner and I D Sharp and M Stutzmann},
url = {\<Go to ISI\>://WOS:000526331500009},
doi = {10.1021/acs.jpcc.0c00254},
issn = {1932-7447},
year = {2020},
date = {2020-04-09},
journal = {Journal of Physical Chemistry C},
volume = {124},
number = {14},
pages = {7668-7676},
abstract = {Gallium-zinc oxynitride (GZNO) is a promising material system for solar-driven overall water splitting, as it exhibits a tunable band gap in the visible range, beneficial positions of valence and conduction band edges, and promising long-term stability. Fabrication of GZNO is traditionally accomplished via a solid state reaction pathway. This limits the growth of thin films or large single crystals and the precise control of the composition, which complicates investigations about fundamental properties of the material, including, for example, the influence of the single constituent ratios on the band gap. In this work, we present the growth of GZNO thin films on sapphire by plasma-assisted molecular beam epitaxy (MBE). The thin films exhibit a crystallite size of up to 50 nm and a wurtzite crystal structure with distinct short-range disorder. Variations of Ga/Zn and N/O flux ratios are found to influence the optical absorption edge of the alloy without major impact on the Urbach energy. Controlled change of the composition of the alloy reveals that the band gap reduction is caused by both an increased valence band energy, which is correlated with the N content, and a decrease of the conduction band energy which is induced by increasing Zn content. Based on these findings, GZNO thin films with band gaps of down to 2.0 eV were fabricated and their photoelectrical properties assessed. Using MBE, we overcome compositional restrictions typically associated with stoichiometric GaN:ZnO solid solutions and provide unprecedented access to new compounds within this materials class. In doing so, we elucidate the specific role of individual elements on band edge energetics and demonstrate new routes to band gap engineering for future photocatalytic and photoelectrochemical applications.},
keywords = {Foundry Inorganic, Solid-Liquid},
pubstate = {published},
tppubtype = {article}
}
K Trofymchuk, V Glembockyte, L Grabenhorst, F Steiner, C Vietz, C Close, M Pfeiffer, L Richter, M L Schütte, F Selbach, R Yaadav, J Zähringer, Q Wei, A Ozcan, B Lalkens, G P Acuna, P Tinnefeld
Addressable Nanoantennas with Cleared Hotspots for Single-Molecule Detection on a Portable Smartphone Microscope Journal Article
In: bioRxiv, pp. 2020.04.09.032037, 2020.
Abstract | Links | Tags: Foundry Inorganic, Foundry Organic, Molecularly-Functionalized
@article{,
title = {Addressable Nanoantennas with Cleared Hotspots for Single-Molecule Detection on a Portable Smartphone Microscope},
author = {K Trofymchuk and V Glembockyte and L Grabenhorst and F Steiner and C Vietz and C Close and M Pfeiffer and L Richter and M L Sch\"{u}tte and F Selbach and R Yaadav and J Z\"{a}hringer and Q Wei and A Ozcan and B Lalkens and G P Acuna and P Tinnefeld},
url = {http://biorxiv.org/content/early/2020/04/09/2020.04.09.032037.abstract},
doi = {10.1101/2020.04.09.032037},
year = {2020},
date = {2020-04-09},
urldate = {2020-04-09},
journal = {bioRxiv},
pages = {2020.04.09.032037},
abstract = {The advent of highly sensitive photodetectors1,2 and the development of photostabilization strategies3 made detecting the fluorescence of a single molecule a routine task in many labs around the world. However, to this day, this process requires cost-intensive optical instruments due to the truly nanoscopic signal of a single emitter. Simplifying single-molecule detection would enable many exciting applications, e.g. in point-of-care diagnostic settings, where costly equipment would be prohibitive.4 Here, we introduce addressable NanoAntennas with Cleared HOtSpots (NACHOS) that are scaffolded by DNA origami nanostructures and can be specifically tailored for the incorporation of bioassays. Single emitters placed in the NACHOS emit up to 461-fold brighter enabling their detection with a customary smartphone camera and an 8-US-dollar objective lens. To prove the applicability of our system, we built a portable, battery-powered smartphone microscope and successfully carried out an exemplary single-molecule detection assay for DNA specific to antibiotic-resistant Klebsiella pneumonia "on the road “.Competing Interest StatementPT and GPA are inventors on a patent of the described Bottom-up method for fluorescence enhancement in molecular assays, EP1260316.1, 2012, US20130252825 A1.},
keywords = {Foundry Inorganic, Foundry Organic, Molecularly-Functionalized},
pubstate = {published},
tppubtype = {article}
}
Y Xia, W Chen, P Zhang, S Liu, K Wang, X Yang, H Tang, L Lian, J He, X Liu, G Liang, M Tan, L Gao, H Liu, H Song, D Zhang, J Gao, K Wang, X Lan, X Zhang, P Müller-Buschbaum, J Tang, J Zhang
Facet Control for Trap-State Suppression in Colloidal Quantum Dot Solids Journal Article
In: Advanced Functional Materials, vol. 30, no. 22, pp. 2000594, 2020, ISSN: 1616-301X.
Abstract | Links | Tags: Foundry Inorganic, Solid-Solid
@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}
}
C A Walenta, C Courtois, S L Kollmannsberger, M Eder, M Tschurl, U Heiz
In: Acs Catalysis, vol. 10, no. 7, pp. 4080-4091, 2020, ISSN: 2155-5435.
Abstract | Links | Tags: Foundry Inorganic, Molecularly-Functionalized
@article{,
title = {Surface Species in Photocatalytic Methanol Reforming on Pt/TiO2(110): Learning from Surface Science Experiments for Catalytically Relevant Conditions},
author = {C A Walenta and C Courtois and S L Kollmannsberger and M Eder and M Tschurl and U Heiz},
url = {\<Go to ISI\>://WOS:000526395000011},
doi = {10.1021/acscatal.0c00260},
issn = {2155-5435},
year = {2020},
date = {2020-04-03},
urldate = {2020-04-03},
journal = {Acs Catalysis},
volume = {10},
number = {7},
pages = {4080-4091},
abstract = {Photocatalytic hydrogen evolution from methanol is a standard test reaction for photocatalyst materials. Surprisingly, the exact chemical mechanism is still widely discussed in the literature. In order to disentangle photochemical from thermal reaction steps and gain insights on the atomic level, we use a Pt cluster-loaded TiO2(110) photocatalyst in very well-defined environments. Using Auger electron spectroscopy, temperature-programmed desorption/reaction, isotopic labeling, and isothermal photoreactions, it is possible to identify the surface species present on the catalyst under photocatalytic conditions. Furthermore, an initial conditioning of the photocatalyst is observed and attributed to thermal dehydrogenation of methanol to CO species on the cluster. The analysis of the isothermal photoreactions reveals that the photo-oxidation kinetics are not significantly affected by cocatalyst loading. The observed conversion and product distribution of formaldehyde and methyl formate can be rationalized with kinetic parameters gained from the bare TiO2(110) crystal. The work leads to a detailed mechanistic understanding of the surface species and paves the way for an educated microkinetic modeling approach, which may be extended to a variety of noble metal cocatalysts and other TiO2 modifications.},
keywords = {Foundry Inorganic, Molecularly-Functionalized},
pubstate = {published},
tppubtype = {article}
}
B Charles, M T Weller, S Rieger, L E Hatcher, P F Henry, J Feldmann, D Wolverson, C C Wilson
Phase Behavior and Substitution Limit of Mixed Cesium-Formamidinium Lead Triiodide Perovskites Journal Article
In: Chemistry of Materials, vol. 32, no. 6, pp. 2282-2291, 2020, ISSN: 0897-4756.
Abstract | Links | Tags: Foundry Inorganic, Solid-Solid
@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}
}
N Giesbrecht, A Weis, T Bein
Formation of stable 2D methylammonium antimony iodide phase for lead-free perovskite-like solar cells* Journal Article
In: Journal of Physics: Energy, vol. 2, no. 2, pp. 024007, 2020, ISSN: 2515-7655.
Abstract | Links | Tags: Foundry Inorganic, Solid-Solid
@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}
}
M Kick, C Grosu, M Schuderer, C Scheurer, H Oberhofer
Mobile Small Polarons Qualitatively Explain Conductivity in Lithium Titanium Oxide Battery Electrodes Journal Article
In: Journal of Physical Chemistry Letters, vol. 11, no. 7, pp. 2535-2540, 2020, ISSN: 1948-7185.
Abstract | Links | Tags: Foundry Inorganic, Solid-Solid
@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}
}
J Fichtner, S Watzele, B Garlyyev, R M Kluge, F Haimerl, H A El-Sayed, W J Li, F M Maillard, L Dubau, R Chattot, J Michalicka, J M Macak, W Wang, D Wang, T Gigl, C Hugenschmidt, A S Bandarenka
Tailoring the Oxygen Reduction Activity of Pt Nanoparticles through Surface Defects: A Simple Top-Down Approach Journal Article
In: Acs Catalysis, vol. 10, no. 5, pp. 3131-3142, 2020, ISSN: 2155-5435.
Abstract | Links | Tags: Foundry Inorganic, Solid-Liquid
@article{,
title = {Tailoring the Oxygen Reduction Activity of Pt Nanoparticles through Surface Defects: A Simple Top-Down Approach},
author = {J Fichtner and S Watzele and B Garlyyev and R M Kluge and F Haimerl and H A El-Sayed and W J Li and F M Maillard and L Dubau and R Chattot and J Michalicka and J M Macak and W Wang and D Wang and T Gigl and C Hugenschmidt and A S Bandarenka},
url = {\<Go to ISI\>://WOS:000518876300024},
doi = {10.1021/acscatal.9b04974},
issn = {2155-5435},
year = {2020},
date = {2020-03-06},
urldate = {2020-03-06},
journal = {Acs Catalysis},
volume = {10},
number = {5},
pages = {3131-3142},
abstract = {Results from Pt model catalyst surfaces have demonstrated that surface defects, in particular surface concavities, can improve the oxygen reduction reaction (ORR) kinetics. It is, however, a challenging task to synthesize nanostructured catalysts with such defective surfaces. Hence, we present a one-step and upscalable top-down approach to produce a Pt/C catalyst (with similar to 3 nm Pt nanoparticle diameter). Using high-resolution transmission electron microscopy and tomography, electrochemical techniques, high-energy X-ray measurements, and positron annihilation spectroscopy, we provide evidence of a high density of surface defects (including surface concavities). The ORR activity of the developed catalyst exceeds that of a commercial Pt/C catalyst, at least 2.7 times in terms of specific activity (similar to 1.62 mA/cm(Pt)(2), at 0.9 V vs the reversible hydrogen electrode) and at least 1.7 times in terms of mass activity (similar to 712 mA/mg(Pt)), which can be correlated to the enhanced amount of surface defects. In addition, the technique used here reduces the complexity of the synthesis (and therefore production costs) in comparison to state of the art bottom-up techniques.},
keywords = {Foundry Inorganic, Solid-Liquid},
pubstate = {published},
tppubtype = {article}
}
S J Hao, M Hetzl, V F Kunzelmann, S Matich, Q L Sai, C T Xia, I D Sharp, M Stutzmann
Sub-bandgap optical spectroscopy of epitaxial beta-Ga2O3 thin films Journal Article
In: Applied Physics Letters, vol. 116, no. 9, 2020, ISSN: 0003-6951.
Abstract | Links | Tags: Foundry Inorganic, Solid-Solid
@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}
}
R S Markl, N Hohn, E Hupf, L Biessmann, V Korstgens, L P Kreuzer, G Mangiapia, M Pomm, A Kriele, E Rivard, P Muller-Buschbaum
Comparing the backfilling of mesoporous titania thin films with hole conductors of different sizes sharing the same mass density Journal Article
In: Iucrj, vol. 7, pp. 268-275, 2020, ISSN: 2052-2525.
Abstract | Links | Tags: Foundry Inorganic, Solid-Solid
@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}
}
L Hüttenhofer, F Eckmann, A Lauri, J Cambiasso, E Pensa, Y Li, E Cortés, I D Sharp, S A Maier
Anapole Excitations in Oxygen-Vacancy-Rich TiO2–x Nanoresonators: Tuning the Absorption for Photocatalysis in the Visible Spectrum Journal Article
In: ACS Nano, vol. 14, no. 2, pp. 2456-2464, 2020, ISSN: 1936-0851.
Links | Tags: Foundry Inorganic
@article{,
title = {Anapole Excitations in Oxygen-Vacancy-Rich TiO2\textendashx Nanoresonators: Tuning the Absorption for Photocatalysis in the Visible Spectrum},
author = {L H\"{u}ttenhofer and F Eckmann and A Lauri and J Cambiasso and E Pensa and Y Li and E Cort\'{e}s and I D Sharp and S A Maier},
url = {https://doi.org/10.1021/acsnano.9b09987},
doi = {10.1021/acsnano.9b09987},
issn = {1936-0851},
year = {2020},
date = {2020-02-25},
journal = {ACS Nano},
volume = {14},
number = {2},
pages = {2456-2464},
keywords = {Foundry Inorganic},
pubstate = {published},
tppubtype = {article}
}
H Bi, C A Palma, Y X Gong, K Stallhofer, M Nuber, C Jing, F Meggendorfer, S Z Wen, C Y Yam, R Kienberger, M Elbing, M Mayor, H Iglev, J V Barth, J Reichert
Electron-Phonon Coupling in Current-Driven Single-Molecule Junctions Journal Article
In: Journal of the American Chemical Society, vol. 142, no. 7, pp. 3384-3391, 2020, ISSN: 0002-7863.
Abstract | Links | Tags: Foundry Inorganic, Solid-Solid
@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}
}
V Giegold, L Lange, R Ciesielski, A Hartschuh
Non-linear Raman scattering intensities in graphene Journal Article
In: Nanoscale, 2020, ISSN: 2040-3364.
Abstract | Links | Tags: Foundry Inorganic
@article{,
title = {Non-linear Raman scattering intensities in graphene},
author = {V Giegold and L Lange and R Ciesielski and A Hartschuh},
url = {http://dx.doi.org/10.1039/C9NR10654E},
doi = {10.1039/C9NR10654E},
issn = {2040-3364},
year = {2020},
date = {2020-02-18},
journal = {Nanoscale},
abstract = {We show that the Raman scattering signals of the two dominant Raman bands G and 2D of graphene sensitively depend on the laser intensity in opposite ways. High electronic temperatures reached for pulsed laser excitation lead to an asymmetric Fermi\textendashDirac distribution at the different optically resonant states contributing to Raman scattering. This results in a partial Pauli blocking of destructively interfering quantum pathways for G band scattering, which is observed as a super-linear increase of the G band intensity with laser power. The 2D band, on the other hand, exhibits sub-linear intensity scaling due to the blocking of constructively interfering contributions. The opposite intensity dependencies of the two bands are found to reduce the observed 2D/G ratio, a key quantity used for characterizing graphene samples, by more than factor two for electronic temperatures around 3000 K.},
keywords = {Foundry Inorganic},
pubstate = {published},
tppubtype = {article}
}
P Zimmermann, A W Holleitner
On-site tuning of the carrier lifetime in silicon for on-chip THz circuits using a focused beam of helium ions Journal Article
In: Applied Physics Letters, vol. 116, no. 7, pp. 073501, 2020, ISSN: 0003-6951.
Links | Tags: Foundry Inorganic, Solid-Solid
@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}
}
N Li, L Song, N Hohn, S Saxena, W Cao, X Y Jiang, P Muller-Buschbaum
Nanoscale crystallization of a low band gap polymer in printed titania mesopores Journal Article
In: Nanoscale, vol. 12, no. 6, pp. 4085-4093, 2020, ISSN: 2040-3364.
Abstract | Links | Tags: Foundry Inorganic, Solid-Solid
@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}
}
L Grabenhorst, K Trofymchuk, F Steiner, V Glembockyte, P Tinnefeld
Fluorophore photostability and saturation in the hotspot of DNA origami nanoantennas Journal Article
In: Methods and Applications in Fluorescence, vol. 8, no. 2, pp. 024003, 2020, ISSN: 2050-6120.
Abstract | Links | Tags: Foundry Inorganic, Foundry Organic, Molecularly-Functionalized
@article{,
title = {Fluorophore photostability and saturation in the hotspot of DNA origami nanoantennas},
author = {L Grabenhorst and K Trofymchuk and F Steiner and V Glembockyte and P Tinnefeld},
url = {http://dx.doi.org/10.1088/2050-6120/ab6ac8},
doi = {10.1088/2050-6120/ab6ac8},
issn = {2050-6120},
year = {2020},
date = {2020-02-05},
urldate = {2020-02-05},
journal = {Methods and Applications in Fluorescence},
volume = {8},
number = {2},
pages = {024003},
abstract = {Fluorescent dyes used for single-molecule spectroscopy can undergo millions of excitation-emission cycles before photobleaching. Due to the upconcentration of light in a plasmonic hotspot, the conditions for fluorescent dyes are even more demanding in DNA origami nanoantennas. Here, we briefly review the current state of fluorophore stabilization for single-molecule imaging and reveal additional factors relevant in the context of plasmonic fluorescence enhancement. We show that despite the improved photostability of single-molecule fluorophores by DNA origami nanoantennas, their performance in the intense electric fields in plasmonic hotspots is still limited by the underlying photophysical processes, such as formation of dim states and photoisomerization. These photophysical processes limit the photon count rates, increase heterogeneity and aggravate quantification of fluorescence enhancement factors. These factors also reduce the time resolution that can be achieved in biophysical single-molecule experiments. Finally, we show how the photophysics of a DNA hairpin assay with a fluorophore-quencher pair can be influenced by plasmonic DNA origami nanoantennas leading to implications for their use in fluorescence-based diagnostic assays. Especially, we show that such assays can produce false positive results by premature photobleaching of the dark quencher.},
keywords = {Foundry Inorganic, Foundry Organic, Molecularly-Functionalized},
pubstate = {published},
tppubtype = {article}
}
D Ruhstorfer, S Mejia, M Ramsteiner, M Döblinger, H Riedl, J J Finley, G Koblmüller
Demonstration of n-type behavior in catalyst-free Si-doped GaAs nanowires grown by molecular beam epitaxy Journal Article
In: Applied Physics Letters, vol. 116, no. 5, pp. 052101, 2020.
Links | Tags: Foundry Inorganic, Molecularly-Functionalized
@article{,
title = {Demonstration of n-type behavior in catalyst-free Si-doped GaAs nanowires grown by molecular beam epitaxy},
author = {D Ruhstorfer and S Mejia and M Ramsteiner and M D\"{o}blinger and H Riedl and J J Finley and G Koblm\"{u}ller},
url = {https://aip.scitation.org/doi/abs/10.1063/1.5134687},
doi = {10.1063/1.5134687},
year = {2020},
date = {2020-02-04},
journal = {Applied Physics Letters},
volume = {116},
number = {5},
pages = {052101},
keywords = {Foundry Inorganic, Molecularly-Functionalized},
pubstate = {published},
tppubtype = {article}
}
O E O Zeman, Von F O Rohr, L Neudert, W Schnick
Facile One-step Synthesis of Zn1-xMnxSiN2 Nitride Semiconductor Solid Solutions via Solid-state Metathesis Reaction Journal Article
In: Zeitschrift Fur Anorganische Und Allgemeine Chemie, 2020, ISSN: 0044-2313.
Links | Tags: Foundry Inorganic
@article{,
title = {Facile One-step Synthesis of Zn1-xMnxSiN2 Nitride Semiconductor Solid Solutions via Solid-state Metathesis Reaction},
author = {O E O Zeman and Von F O Rohr and L Neudert and W Schnick},
url = {\<Go to ISI\>://WOS:000510472600001},
doi = {10.1002/zaac.201900315},
issn = {0044-2313},
year = {2020},
date = {2020-02-03},
journal = {Zeitschrift Fur Anorganische Und Allgemeine Chemie},
keywords = {Foundry Inorganic},
pubstate = {published},
tppubtype = {article}
}
T Scholz, F Pielnhofer, R Eger, B V Lotsch
Lanthanide orthothiophosphates revisited: single-crystal X-ray, Raman, and DFT studies of TmPS4 and YbPS4 Journal Article
In: Zeitschrift für Naturforschung B, vol. 75, 2020.
Links | Tags: Foundry Inorganic
@article{,
title = {Lanthanide orthothiophosphates revisited: single-crystal X-ray, Raman, and DFT studies of TmPS4 and YbPS4},
author = {T Scholz and F Pielnhofer and R Eger and B V Lotsch},
doi = {10.1515/znb-2019-0217},
year = {2020},
date = {2020-01-28},
journal = {Zeitschrift f\"{u}r Naturforschung B},
volume = {75},
keywords = {Foundry Inorganic},
pubstate = {published},
tppubtype = {article}
}
Q He, A T S Freiberg, M U M Patel, S Qian, H A Gasteiger
Operando Identification of Liquid Intermediates in Lithium–Sulfur Batteries via Transmission UV–vis Spectroscopy Journal Article
In: Journal of The Electrochemical Society, vol. 167, no. 8, pp. 080508, 2020, ISSN: 0013-4651 1945-7111.
Abstract | Links | Tags: Foundry Inorganic, Solid-Solid
@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}
}
M Däntl, P Ganter, K Szendrei-Temesi, A Jiménez-Solano, B V Lotsch
Customizing H3Sb3P2O14 nanosheet sensors by reversible vapor-phase amine intercalation Journal Article
In: Nanoscale Horizons, vol. 5, no. 1, pp. 74-81, 2020, ISSN: 2055-6756.
Abstract | Links | Tags: Foundry Inorganic
@article{,
title = {Customizing H3Sb3P2O14 nanosheet sensors by reversible vapor-phase amine intercalation},
author = {M D\"{a}ntl and P Ganter and K Szendrei-Temesi and A Jim\'{e}nez-Solano and B V Lotsch},
url = {http://dx.doi.org/10.1039/C9NH00434C},
doi = {10.1039/C9NH00434C},
issn = {2055-6756},
year = {2020},
date = {2020-01-01},
journal = {Nanoscale Horizons},
volume = {5},
number = {1},
pages = {74-81},
abstract = {Harvesting the large property space of 2D materials and their molecular-level fine-tuning is of utmost importance for future applications such as miniaturized sensors for environmental monitoring or biomedical detection. Therefore, developing straightforward strategies for the reversible and gradual fine-tuning of nanosheet properties with soft chemical intercalation methods is in high demand. Herein we address this challenge by customizing the host\textendashguest interactions of nanosheets based on the solid acid H3Sb3P2O14 by vapor-phase amine-intercalation with primary alkylamines. Fine-tuning of the structural and chemical properties of the intercalated nanosheets is achieved by applying a two-step, post-synthetic intercalation strategy via the vapor phase. The method allows for the gradual and reversible replacement of one amine type by another. Hence, fine-tuning of the d-spacing in the sub-r{A} regime is accomplished and offers exquisite control of the properties of the thin films such as refractive index, polarity, film thickness and sensitivity towards solvent vapors. Moreover, we employ amine replacement to pattern thin films by locally resolved amine intercalation and subsequent washing, leading to spatially dependent property profiles. This process thus adds a new vapor-phase, amine-based variant to the toolbox of soft lithography.},
keywords = {Foundry Inorganic},
pubstate = {published},
tppubtype = {article}
}
J Klein, L Sigl, A Hötger, S Gyger, K Barthelmi, M Florian, A Kerelsky, E Mitterreiter, C Kastl, S Rey, T Taniguchi, K Watanabe, F Jahnke, V Zwiller, K Jöns, A Pasupathy, F Ross, K Müller, U Wurstbauer, J J Finley, A W Holleitner
Scalable single-photon sources in atomically thin MoS2 Journal Article
In: vol. 11471, 2020.
Abstract | Links | Tags: Foundry Inorganic, Solid-Solid
@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}
}
F Podjaski, D Weber, S Zhang, L Diehl, R Eger, V Duppel, E Alarcón-Lladó, G Richter, F Haase, A Fontcuberta I Morral, C Scheu, B V Lotsch
Rational strain engineering in delafossite oxides for highly efficient hydrogen evolution catalysis in acidic media Journal Article
In: Nature Catalysis, vol. 3, no. 1, pp. 55-63, 2020, ISSN: 2520-1158.
Abstract | Links | Tags: Foundry Inorganic, Solid-Liquid
@article{nokey,
title = {Rational strain engineering in delafossite oxides for highly efficient hydrogen evolution catalysis in acidic media},
author = {F Podjaski and D Weber and S Zhang and L Diehl and R Eger and V Duppel and E Alarc\'{o}n-Llad\'{o} and G Richter and F Haase and A Fontcuberta I Morral and C Scheu and B V Lotsch},
url = {https://doi.org/10.1038/s41929-019-0400-x},
doi = {10.1038/s41929-019-0400-x},
issn = {2520-1158},
year = {2020},
date = {2020-01-01},
journal = {Nature Catalysis},
volume = {3},
number = {1},
pages = {55-63},
abstract = {The rational design of hydrogen evolution reaction electrocatalysts that can compete with platinum is an outstanding challenge in the process of designing viable power-to-gas technologies. Here, we introduce delafossites as a family of hydrogen evolution reaction electrocatalysts in acidic media. We show that, in PdCoO2, the inherently strained Pd metal sublattice acts as a pseudomorphic template for the growth of a tensile-strained Pd-rich capping layer under reductive conditions. The surface modification ranges up to 400 nm and continuously improves the electrocatalytic activity by simultaneously increasing the exchange current density and by reducing the Tafel slope down to 38 mV dec−1, leading to overpotentials η10 \< 15 mV. The improved activity is attributed to the operando stabilization of a β-PdHx phase with enhanced surface catalytic properties with respect to pure or nanostructured palladium. These findings illustrate how operando-induced electrodissolution can be used as a top-down design concept through the strain-stabilized formation of catalytically active phases.},
keywords = {Foundry Inorganic, Solid-Liquid},
pubstate = {published},
tppubtype = {article}
}
J Klein, A Kerelsky, M Lorke, M Florian, F Sigger, J Kiemle, M C Reuter, T Taniguchi, K Watanabe, J J Finley, A N Pasupathy, A W Holleitner, F M Ross, U Wurstbauer
Impact of substrate induced band tail states on the electronic and optical properties of MoS2 Journal Article
In: Applied Physics Letters, vol. 115, no. 26, 2019, ISSN: 0003-6951.
Links | Tags: Foundry Inorganic
@article{,
title = {Impact of substrate induced band tail states on the electronic and optical properties of MoS2},
author = {J Klein and A Kerelsky and M Lorke and M Florian and F Sigger and J Kiemle and M C Reuter and T Taniguchi and K Watanabe and J J Finley and A N Pasupathy and A W Holleitner and F M Ross and U Wurstbauer},
url = {\<Go to ISI\>://WOS:000505613600019},
doi = {10.1063/1.5131270},
issn = {0003-6951},
year = {2019},
date = {2019-12-30},
journal = {Applied Physics Letters},
volume = {115},
number = {26},
keywords = {Foundry Inorganic},
pubstate = {published},
tppubtype = {article}
}
A Haffner, A K Hatz, C Hoch, B V Lotsch, D Johrendt
Synthesis and Structure of the Sodium Phosphidosilicate Na2SiP2 Journal Article
In: European Journal of Inorganic Chemistry, 2019, ISSN: 1434-1948.
Links | Tags: Foundry Inorganic
@article{,
title = {Synthesis and Structure of the Sodium Phosphidosilicate Na2SiP2},
author = {A Haffner and A K Hatz and C Hoch and B V Lotsch and D Johrendt},
url = {\<Go to ISI\>://WOS:000511390500001},
doi = {10.1002/ejic.201901083},
issn = {1434-1948},
year = {2019},
date = {2019-12-29},
journal = {European Journal of Inorganic Chemistry},
keywords = {Foundry Inorganic},
pubstate = {published},
tppubtype = {article}
}
H Huang, L Wu, Y Wang, A F Richter, M Döblinger, J Feldmann
Facile Synthesis of FAPbI3 Nanorods Journal Article
In: Nanomaterials, vol. 10, no. 1, pp. 72, 2019, ISSN: 2079-4991.
Links | Tags: Foundry Inorganic
@article{,
title = {Facile Synthesis of FAPbI3 Nanorods},
author = {H Huang and L Wu and Y Wang and A F Richter and M D\"{o}blinger and J Feldmann},
url = {https://www.mdpi.com/2079-4991/10/1/72},
issn = {2079-4991},
year = {2019},
date = {2019-12-29},
journal = {Nanomaterials},
volume = {10},
number = {1},
pages = {72},
keywords = {Foundry Inorganic},
pubstate = {published},
tppubtype = {article}
}
A M Ferrenti, S Klemenz, S M Lei, X Y Song, P Ganter, B V Lotsch, L M Schoop
Change in Magnetic Properties upon Chemical Exfoliation of FeOCl Journal Article
In: Inorganic Chemistry, vol. 59, no. 2, pp. 1176-1182, 2019, ISSN: 0020-1669.
Links | Tags: Foundry Inorganic
@article{,
title = {Change in Magnetic Properties upon Chemical Exfoliation of FeOCl},
author = {A M Ferrenti and S Klemenz and S M Lei and X Y Song and P Ganter and B V Lotsch and L M Schoop},
url = {\<Go to ISI\>://WOS:000509420100027},
doi = {10.1021/acs.inorgchem.9b02856},
issn = {0020-1669},
year = {2019},
date = {2019-12-27},
journal = {Inorganic Chemistry},
volume = {59},
number = {2},
pages = {1176-1182},
keywords = {Foundry Inorganic},
pubstate = {published},
tppubtype = {article}
}
S Zhang, L Diehl, S Wrede, B V Lotsch, C Scheu
Structural Evolution of Ni-Based Co-Catalysts on [Ca2Nb3O10]− Nanosheets during Heating and Their Photocatalytic Properties Journal Article
In: Catalysts, vol. 10, no. 1, pp. 13, 2019, ISSN: 2073-4344.
Links | Tags: Foundry Inorganic
@article{,
title = {Structural Evolution of Ni-Based Co-Catalysts on [Ca2Nb3O10]− Nanosheets during Heating and Their Photocatalytic Properties},
author = {S Zhang and L Diehl and S Wrede and B V Lotsch and C Scheu},
url = {https://www.mdpi.com/2073-4344/10/1/13},
issn = {2073-4344},
year = {2019},
date = {2019-12-20},
journal = {Catalysts},
volume = {10},
number = {1},
pages = {13},
keywords = {Foundry Inorganic},
pubstate = {published},
tppubtype = {article}
}
Y Negrín-Montecelo, M Comesaña-Hermo, L K Khorashad, A Sousa-Castillo, Z Wang, M Pérez-Lorenzo, T Liedl, A O Govorov, M A Correa-Duarte
In: ACS Energy Letters, pp. 395-402, 2019.
Links | Tags: Foundry Inorganic, Molecularly-Functionalized
@article{,
title = {Photophysical Effects behind the Efficiency of Hot Electron Injection in Plasmon-Assisted Catalysis: The Joint Role of Morphology and Composition},
author = {Y Negr\'{i}n-Montecelo and M Comesa\~{n}a-Hermo and L K Khorashad and A Sousa-Castillo and Z Wang and M P\'{e}rez-Lorenzo and T Liedl and A O Govorov and M A Correa-Duarte},
url = {https://doi.org/10.1021/acsenergylett.9b02478},
doi = {10.1021/acsenergylett.9b02478},
year = {2019},
date = {2019-12-12},
journal = {ACS Energy Letters},
pages = {395-402},
keywords = {Foundry Inorganic, Molecularly-Functionalized},
pubstate = {published},
tppubtype = {article}
}
S Fust, A Faustmann, D J Carrad, J Bissinger, B Loitsch, M Döblinger, J Becker, G Abstreiter, J J Finley, G Koblmüller
Quantum-Confinement-Enhanced Thermoelectric Properties in Modulation-Doped GaAs–AlGaAs Core–Shell Nanowires Journal Article
In: Advanced Materials, vol. 32, no. 4, pp. 1905458, 2019, ISSN: 0935-9648.
Abstract | Links | Tags: Foundry Inorganic, Molecularly-Functionalized
@article{,
title = {Quantum-Confinement-Enhanced Thermoelectric Properties in Modulation-Doped GaAs\textendashAlGaAs Core\textendashShell Nanowires},
author = {S Fust and A Faustmann and D J Carrad and J Bissinger and B Loitsch and M D\"{o}blinger and J Becker and G Abstreiter and J J Finley and G Koblm\"{u}ller},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/adma.201905458},
doi = {10.1002/adma.201905458},
issn = {0935-9648},
year = {2019},
date = {2019-12-09},
journal = {Advanced Materials},
volume = {32},
number = {4},
pages = {1905458},
abstract = {Abstract Nanowires (NWs) hold great potential in advanced thermoelectrics due to their reduced dimensions and low-dimensional electronic character. However, unfavorable links between electrical and thermal conductivity in state-of-the-art unpassivated NWs have, so far, prevented the full exploitation of their distinct advantages. A promising model system for a surface-passivated one-dimensional (1D)-quantum confined NW thermoelectric is developed that enables simultaneously the observation of enhanced thermopower via quantum oscillations in the thermoelectric transport and a strong reduction in thermal conductivity induced by the core\textendashshell heterostructure. High-mobility modulation-doped GaAs/AlGaAs core\textendashshell NWs with thin (sub-40 nm) GaAs NW core channel are employed, where the electrical and thermoelectric transport is characterized on the same exact 1D-channel. 1D-sub-band transport at low temperature is verified by a discrete stepwise increase in the conductance, which coincided with strong oscillations in the corresponding Seebeck voltage that decay with increasing sub-band number. Peak Seebeck coefficients as high as ≈65\textendash85 µV K−1 are observed for the lowest sub-bands, resulting in equivalent thermopower of S2σ ≈ 60 µW m−1 K−2 and S2G ≈ 0.06 pW K−2 within a single sub-band. Remarkably, these core\textendashshell NW heterostructures also exhibit thermal conductivities as low as ≈3 W m−1 K−1, about one order of magnitude lower than state-of-the-art unpassivated GaAs NWs.},
keywords = {Foundry Inorganic, Molecularly-Functionalized},
pubstate = {published},
tppubtype = {article}
}