A5013887138- Organic Electronics and Photovoltaics
- Conducting polymers and applications
- Perovskite Materials and Applications
- Spectroscopy and Quantum Chemical Studies
- Luminescence and Fluorescent Materials
- Chalcogenide Semiconductor Thin Films
- Organic Light-Emitting Diodes Research
- Carbon Nanotubes in Composites
- Photoreceptor and optogenetics research
- Quantum Dots Synthesis And Properties
- Molecular Junctions and Nanostructures
- Photochemistry and Electron Transfer Studies
- Mechanical and Optical Resonators
- Photosynthetic Processes and Mechanisms
- Porphyrin and Phthalocyanine Chemistry
- solar cell performance optimization
- Machine Learning in Materials Science
- Silicon and Solar Cell Technologies
- Fullerene Chemistry and Applications
- Thin-Film Transistor Technologies
- Photovoltaic System Optimization Techniques
- Photochromic and Fluorescence Chemistry
- Nanowire Synthesis and Applications
- Copper-based nanomaterials and applications
- Synthesis and Properties of Aromatic Compounds
Friedrich-Alexander-Universität Erlangen-Nürnberg
2020-2025
Helmholtz Institute Erlangen-Nürnberg
2021-2025
Forschungszentrum Jülich
2021-2025
IMDEA Nanoscience
2013-2022
Madrid Institute for Advanced Studies
2012-2022
University of Toledo
2022
IMDEA Food
2018
Faraday Technology (United States)
2014-2017
The Synergetic Innovation Center for Advanced Materials
2016
Nanjing University of Posts and Telecommunications
2016
The present Perspective critically re-examines the photophysics of para-distyrylbenzene (DSB) as a prototype herringbone-arranged H-aggregates to resolve apparent contradiction frequently reported "aggregation-induced emission quenching" in on one side and highly emissive DSB crystals other discusses signatures fate excitons single- polycrystalline samples, including size polarization effects.
Solid state luminescence enhancement (SLE) of conjugated organic materials has had a great impact in science, but deep understanding been rather limited to date. Here, we investigate prototype example SLE materials, cyano-substituted distyrylbenzene (DCS), by varying systematically and subtly the substitution pattern (inter alia position cyano-substituent) give largely different photoresponse fluid solid solution as well crystalline state. The combination quantitative (ultra)fast optical...
Abstract The development of a robust quasi-ohmic contact with minimal resistance, good stability and cost-effectiveness is crucial for perovskite solar cells. We introduce generic approach featuring Lewis-acid layer sandwiched between dopant-free semicrystalline polymer metal electrode in cells, resulting an ideal even at elevated temperature up to 85 °C. solubility Lewis acid alcohol facilitates nondestructive solution processing on top polymer, which boosts hole injection from into by two...
Fluorescence emission and excitation spectra of para-phenylene vinylenes nPV with n=1–4 styryl units are investigated experimentally theoretically as a function the temperature polarizability solvent. At low temperatures, vibronic structures S0↔S1 bands mirror symmetrical negligible 0–0 energy gaps. The frequencies prominent vibrational modes assigned to second longitudinal acoustic phonon entire molecules localized carbon–carbon stretching vibrations. complete calculated at ab initio...
The influence of environmental factors on the degradation process P3HT film has been investigated quantitatively. decay kinetics polymer absorption during variation intensity and spectral distribution incident light, oxygen concentration, humidity level as well temperature are monitored using infrared UV/vis spectroscopy. Additionally, diffusion into fluorescence spectroscopy under same experimental conditions. is light initiated with a strong increase effectiveness toward ultraviolet region...
We present an ultrafast transient absorption spectroscopy system in the visible combining high-sensitivity broadband detection with extreme temporal resolution. The instrument is based on ultrabroadband sub-10fs optical parametric amplifier coupled to multichannel analyzer fast electronics, enabling single-shot at 1kHz repetition rate. For a given pump-probe delay τ, we achieve differential transmission (ΔT∕T) sensitivity of order 10−4 over λpr=490–720nm probe wavelength range by averaging...
We investigated the transient bleaching and absorption of asymmetric core/shell CdSe/CdS nanorods using pump-probe technique. observed ultrafast carrier relaxation identified hole localization dynamics with 650 +/- 80 fs time constant. Upon pumping CdSe core, we found an intense signal in CdS spectral region, which assigned to delocalization electronic wave function on basis envelope-function theoretical calculations.
Organic solar cells (OSCs) are lightweight, have adaptable colors, and can be produced in low‐cost procedures on transparent flexible surfaces. This makes them attractive for markets which other technologies cannot compete, example architectural consumer product integration. However, both efficiencies long term operational stability of OSCs do not yet meet the standards set by their inorganic counterparts. review compiles growing knowledge about how nanostructured carbon materials, such as...
Lead–Tin perovskite solar cells (Pb/Sn PSCs) are limited by the intrinsic instability of Sn(II), which tends to oxidize forming Sn vacancies in films. Herein, a Lewis base β-guanidinopropionic acid (GUA) and hydrazinium iodide (HAI) introduced effectively passivate bulk surface, respectively. The synergistic approach leads Pb/Sn PSCs with promising power conversion efficiency 20.5% owing significantly reduced nonradiative recombination voltage losses. As result, VOC × FF product is improved,...
CsPbI2Br perovskite solar cells (PSCs) have attracted much interest because of their thermodynamic stability, relatively stable cubic phase, and potential as a top cell for tandem applications. However, the open-circuit voltage (VOC) reported to date is in most cases well below detailed balance (DB) limit single-junction PSCs. Here, we demonstrate that adding lead acetate precursor allows us substantially reduce losses due nonradiative recombination. Corresponding champion devices reach...
Herein, we present an autonomous closed-loop optimization of functional OPV devices by optimizing composition and process parameters. An early prediction model the efficiency from optical featuers significantly decreases time one iteration.
Abstract Organic solar cells (OSCs) now approach power conversion efficiencies of 20%. However, in order to enter mass markets, problems upscaling and operational lifetime have be solved, both concerning the connection between processing conditions active layer morphology. Morphological studies supporting development structure–process–property relations are time‐consuming, complex, expensive undergo for which statistics, needed assess significance, difficult collected. This work demonstrates...
The inverse design of tailored organic molecules for specific optoelectronic devices high complexity holds an enormous potential but has not yet been realized. Current models rely on large data sets that generally do exist specialized research fields. We demonstrate a closed-loop workflow combines high-throughput synthesis semiconductors to create datasets and Bayesian optimization discover new hole-transporting materials with properties solar cell applications. predictive were based...
Abstract The pursuit of commercializing perovskite photovoltaics is driving the development various scalable crystallization techniques. Among them, gas quenching a promising approach for high‐throughput deposition films. However, films prepared by gas‐quenching assisted blade coating are susceptible to formation pinholes and frequently show inferior crystallinity if interplay between film coating, drying, kinetics not fully optimized. That arguably requires thorough understanding how single...
Abstract We use an automated research platform combined with machine learning to assess and understand the resilience against air light during production of organic photovoltaic (OPV) devices from over 40 donor acceptor combinations. The standardized protocol high reproducibility results in a dataset variety veracity deploy models encounter links between stability chemical, energetic, morphological structure. find that strongest predictor for air/light is effective gap E g,eff which points...
Interface engineering is crucial to achieving stable perovskite photovoltaic devices. A versatile approach developed tailor interface properties via integrating co-assembled monolayers (co-SAMs) at the p-type buried and by capping a two-dimensional (2D) layer n-type upper with vacuum quenching. Optimized co-SAMs promote coverage of hole transport layer, significantly reducing incidence leakage currents. Based on this foundation, we develop damp-heat-stable solar cells precisely tailoring...
Abstract Traditional optimization methods often face challenges in exploring complex process parameter spaces, which typically result suboptimal local maxima. Here an autonomous framework driven by a machine learning (ML)‐guided automated platform is introduced to optimize the fabrication conditions of additive‐ and passivation‐free perovskite solar cells (PSCs) under ambient conditions. By effectively 6D space, this method identifies five sets achieving efficiencies above 23%, with peak...
Abstract Organic photovoltaics (OPV) now can exceed 20% power conversion efficiency in single junction solar cells. To close the remaining gap to competing technologies, both fill factor and open‐circuit voltage must be optimized. The Langevin reduction is a well‐known concept that measures degree which charge extraction favored over recombination. It therefore ideally suited as an optimization target high‐throughput workflows; however, its evaluation so far requires expert interaction....