A5035328331- Organic Electronics and Photovoltaics
- Conducting polymers and applications
- Perovskite Materials and Applications
- Organic Light-Emitting Diodes Research
- Molecular Junctions and Nanostructures
- Surface and Thin Film Phenomena
- Silicon and Solar Cell Technologies
- Electronic and Structural Properties of Oxides
- solar cell performance optimization
- Thin-Film Transistor Technologies
- Porphyrin and Phthalocyanine Chemistry
- Surface Chemistry and Catalysis
- Semiconductor materials and devices
- Quantum Dots Synthesis And Properties
- Solar Radiation and Photovoltaics
- Photoacoustic and Ultrasonic Imaging
- Advanced Fluorescence Microscopy Techniques
- nanoparticles nucleation surface interactions
- Chalcogenide Semiconductor Thin Films
- Advanced Chemical Physics Studies
- Carbon Nanotubes in Composites
- Solidification and crystal growth phenomena
- Semiconductor materials and interfaces
- Material Dynamics and Properties
- Advanced Optical Sensing Technologies
Friedrich-Alexander-Universität Erlangen-Nürnberg
2017-2024
Forschungszentrum Jülich
1991-2024
Helmholtz Institute Erlangen-Nürnberg
2020-2024
As the power conversion efficiency (PCE) of organic solar cells (OSCs) has surpassed 17% baseline, long-term stability highly efficient OSCs is essential for practical application this photovoltaic technology. Here, photostability and possible degradation mechanisms three state-of-the-art polymer donors with a commonly used nonfullerene acceptor (NFA), IT-4F, are investigated. The active-layer materials show excellent intrinsic photostability. initial morphology, in particular mixed region,...
Abstract There is a strong market driven need for processing organic photovoltaics from eco-friendly solvents. Water-dispersed semiconducting nanoparticles (NPs) satisfy these premises convincingly. However, the necessity of surfactants, which are inevitable stabilizing NPs, major obstacle towards realizing competitive power conversion efficiencies water-processed devices. Here, we report on concept minimizing adverse impact surfactants solar cell performance. A poloxamer facilitates...
Abstract Solution‐processed organic solar cells (OSCs) are promising low‐cost, flexible, portable renewable sources for future energy supply. The state‐of‐the‐art OSCs typically fabricated from a bulk‐heterojunction (BHJ) active layer containing well‐mixed donor and acceptor molecules in the nanometer regime. However, BHJ suffer stability problems caused by severe morphological changes upon thermal or illumination stress. In comparison, single‐component (SCOSCs) based on double‐cable...
Abstract With state‐of‐the‐art organic solar cells (OSCs) surpassing 16% efficiency, stability becomes critical for commercialization. In this work, the power of using photoluminescence (PL) measurements on plain films is demonstrated, as well high‐performance liquid chromatography analysis to reveal origin UV instabilities in OSCs based most commonly used acceptors PC 70 BM ([6,6]‐phenyl‐C71‐butyric acid methyl ester), ITIC...
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...
Abstract Organic semiconductors are in general known to have an inherently lower charge carrier mobility compared their inorganic counterparts. Bimolecular recombination of holes and electrons is important loss mechanism can often be described by the Langevin model. Here, device physics bulk heterojunction solar cells based on a nonfullerene acceptor (IDTBR) combination with poly(3‐hexylthiophene) (P3HT) elucidated, showing unprecedentedly low bimolecular rate. The high fill factor observed...
Abstract A multipurpose interconnection layer based on poly(3,4‐ethylenedioxythiophene) doped with poly(styrene sulfonate) (PEDOT:PSS), and d ‐sorbitol for monolithic perovskite/silicon tandem solar cells is introduced. The of independently processed silicon perovskite subcells a simple add‐on lamination step, alleviating common fabrication complexities devices. It demonstrated experimentally theoretically that PEDOT:PSS an ideal building block manipulating the mechanical electrical...
Abstract A critical bottleneck for improving the performance of organic solar cells (OSC) is minimising non-radiative losses in interfacial charge-transfer (CT) state via formation hybrid energetic states. This requires small offsets often detrimental high external quantum efficiency (EQE). Here, we obtain OSC with both voltage (0.24 V) and photocurrent (EQE > 80%) simultaneously minimised. The CT states separate into free carriers ≈40-ps time constant. We combine device spectroscopic...
Abstract The application of conjugated polymer and fullerene water‐based nanoparticles (NP) as ecofriendly inks for organic photovoltaics (OPVs) is reported. A low bandgap diketopyrrolopyrrole–quinquethiophene (PDPP5T‐2) the methanofullerene PC 71 BM are processed into three types nanoparticles: pristine NPs, mixed polymer:fullerene allowing formation bulk heterojunction (BHJ) composites with different domain sizes. Mild thermal annealing required to melt nanospheres enable interconnected...
Abstract The performance of tandem organic solar cells (OSCs) is directly related to the functionality and reliability interconnecting layer (ICL). However, it a challenge develop fully functional ICL for reliable reproducible fabrication solution‐processed OSCs with minimized optical electrical losses, in particular being compatible various state‐of‐the‐art photoactive materials. Although ICLs have been developed realize impressively high performance, their reliability, reproducibility,...
Abstract Current state‐of‐the‐art organic solar cells (OSCs) still suffer from high losses of open‐circuit voltage ( V OC ). Conventional polymer:fullerene usually exhibit bandgap to greater than 0.8 V. Here a detailed investigation is presented for solution‐processed OSCs based on (6,5) single‐walled carbon nanotube (SWCNT): [6,6]‐phenyl‐C 71 ‐butyric acid methyl ester active layers. Considering the very small optical only 1.22 eV SWCNTs, 0.59 leading low E gap / q − = 0.63 loss observed....
Using x-ray photoemission spectroscopy, we investigated the self-metalation of free-base tetraphenylporphyrin (2HTPP) on thin MgO(100) films Ag(100). The deposition one monolayer 2HTPP MgO results in formation magnesium(ii) (MgTPP) at room temperature. We demonstrate that efficiency reaction drastically depends morphology oxide layers. latter is changed by varying substrate temperature during growth. observe complete metalation when are grown 393 K. increase growth to 573 K leads reduction...
Abstract Spectral differences affect solar cell performance, an effect that is especially visible when comparing different technologies. To reproduce the impact of varying spectra on performance in lab, a unique classification needed, which currently missing literature. The most commonly used classification, average photon energy (APE), not unique, and single APE value may represent various depending location. In this work, we propose method based iterative use k‐means clustering algorithm....
The front dynamics during directional solidification of a dilute binary mixture with noninstantaneous interface kinetic attachment is investigated in the weakly and highly nonlinear regimes. In linear regime we find that, even for small enough coefficient, most unstable mode appreciably modified. With help multiscale analysis, derive amplitude equation that governs close to criticality. It found case constant miscibility gap, studied here, supercritical nature bifurcation remains unaltered....
The electronic structure of Mg and free-base tetraphenylporphyrin films on Ag(100) is investigated by one- two-photon photoemission in combination with calculations using density functional theory the self-consistent $G{W}_{0}$ method. We determine two highest occupied nearly degenerate lowest unoccupied molecular orbitals. Higher states are seen an enhanced emission as a final-state effect. For photon energies close to prominent absorption Soret band we observe strong electron attributed...
Abstract Within this study, we investigate the intrinsic photostability of thin‐film solar cells, here organic photovoltaic cells. Since degradation under natural sun light proceeds within timeframe months and years, process needs to be speeded up for fast material analysis screening, using high‐concentration accelerated lifetime testing (high‐C ALT). For purpose, established setups allowing irradiances 730 equivalents (SE). One key finding our study is that accelerating procedure by such...
We demonstrate sub-diffraction-limited simultaneous two- and three-photon imaging, using a high-power ultrafast fiber laser single-photon avalanche detector array. Despite the 3-times longer excitation wavelength, our demonstration outperforms standard confocal microscopy of same samples.
Epitaxial MgO films on Ag(100) were studied by photoelectron spectroscopy. From the low-energy part of spectra we obtain a negative electron affinity about -0.9 eV. Even though electrons in lowest conduction band are not confined potential barrier at surface, quantum-well resonances observed. The dispersion is determined good agreement with theoretical calculations. Aspects observing image-potential states predicted theory discussed.
Solar spectra change depending on location, weather, and time of day around the world. These spectral variations affect performance photovoltaic (PV) cells modules are not captured by standard testing procedures. We introduce a method to classify use this classification develop procedure reproduce conditions locations within various climate zones. With LED solar simulators becoming commercially available representative sets outdoor found, gap between real world indoor is closing. LED-based...