A5012802779- Perovskite Materials and Applications
- Chalcogenide Semiconductor Thin Films
- Quantum Dots Synthesis And Properties
- 2D Materials and Applications
- Solid-state spectroscopy and crystallography
- Conducting polymers and applications
- solar cell performance optimization
- Magnetic and transport properties of perovskites and related materials
- Silicon and Solar Cell Technologies
- Organic Electronics and Photovoltaics
- Optical properties and cooling technologies in crystalline materials
- Electronic and Structural Properties of Oxides
- Gas Sensing Nanomaterials and Sensors
- Advanced Photocatalysis Techniques
- Cassava research and cyanide
- Semiconductor materials and interfaces
- Cardiovascular Effects of Exercise
- Organic and Molecular Conductors Research
- Health and Medical Research Impacts
- Thermal Expansion and Ionic Conductivity
- Cardiovascular and exercise physiology
- Science, Research, and Medicine
- Luminescence Properties of Advanced Materials
Fraunhofer Institute for Solar Energy Systems
2023-2025
University of Freiburg
2023-2025
University of Oxford
2017-2023
Institute for Atomic and Molecular Physics
2021-2022
University of Cambridge
2021-2022
Harvard University Press
2021
Martin Luther University Halle-Wittenberg
2014-2015
Structural secrets of hybrid perovskites The optoelectronic and photovoltaic applications polycrystalline metal halide perovskite films are notable because grain boundaries in most materials cause scattering charge carriers that decreases performance. Electron microscopy studies these have been hindered by their rapid structural degradation under intense electron beams. Rothmann et al. now present an atomic crystallographic structure formamidinium lead triiodide (FAPbI 3 ) thin obtained...
Mixed-halide perovskites offer bandgap tunability essential for multijunction solar cells; however, a detrimental halide segregation under light is often observed. Here we combine simultaneous in situ photoluminescence and X-ray diffraction measurements to demonstrate clear differences compositional optoelectronic changes associated with MAPb(Br0.5I0.5)3 FA0.83Cs0.17Pb(Br0.4I0.6)3 films. We report evidence low-barrier ionic pathways MAPb(Br0.5I0.5)3, which allow the rearrangement of ions...
While perovskite-based photovoltaics is progressing toward commercialization, it remains an open question which fabrication technology – solution-based, vapor-based, or combinations will pave the way to faster economic breakthrough.
Self-assemble monolayers (SAMs) have become state-of-the-art hole-selective contacts for high-efficiency perovskite-based solar cells due to their easy processing, passivation capability, and low parasitic absorption. Nevertheless, the deposition of SAMs with a monolayer thickness high packing density on metal oxide substrates, critical challenges persist. To overcome these, study focuses impact annealing temperature - an intrinsic yet so far unexplored process parameter during formation...
Perovskite thin-film solar cells are one of the most promising emerging renewable energy technologies because their potential for low-cost, large-area fabrication combined with high conversion efficiencies. Recently, formamidinium lead triiodide (FAPbI3) and other (CH(NH2)2) based perovskites have been explored as interesting alternatives to methylammonium (MAPbI3) they exhibit better thermal stability. However, at present a major challenge is scale-up perovskite from small test-cells full...
Perovskite solar cells based on (CH3NH3)Pb(I,Cl)3 have recently demonstrated rapidly increasing cell efficiencies. Here, we show progress identifying phases present during the growth of perovskite thin films with vacuum-based coevaporation approach using two sources under varying deposition conditions. With in situ X-ray diffraction, crystalline can be identified and monitored real time. For different (CH3NH3)I-to-PbCl2 flux ratios, distinct (CH3NH3)Pb(IxCl(1-x))3 high (x > 0.95) lower <...
Semiconducting polycrystalline thin films are cheap to produce and can be deposited on flexible substrates, yet high-performance electronic devices usually utilize single-crystal semiconductors, owing their superior electrical mobilities longer diffusion lengths. Here we show that the performance of metal-halide perovskites (MHPs) approaches single crystals at room temperature. Combining temperature-dependent terahertz conductivity measurements ab initio calculations uncover a complete...
The efficiency of perovskite/silicon tandem solar cells has exceeded the previous record for III–V-based dual-junction cells. This shows high potential perovskite in multi-junction applications. Perovskite/perovskite/silicon triple-junction are now next step to achieve efficient and low-cost with an even higher than that Here we present a perovskite/perovskite/silicon cell open circuit voltage >2.8 V, which is value reported this structure so far. achieved through employing gas quenching...
Fully textured perovskite silicon tandem solar cells are promising for future low-cost photovoltaic deployment. However, the fill factor and open-circuit voltage of these devices currently limited by high density defects at grain boundaries interfaces with charge transport layers. To address this, we devise a strategy to simultaneously enhance crystallization passivate perovskite/C60 interface. By incorporating urea (CO(NH2)2) as an additive in solution step hybrid evaporation/spin-coating...
Successful chemical doping of metal halide perovskites with small amounts heterovalent metals has attracted recent research attention because its potential to improve long-term material stability and tune absorption spectra. However, some additives have been observed impact negatively on optoelectronic properties, highlighting the importance understanding charge-carrier behavior in doped perovskites. Here, we present an investigation trapping conduction films MAPbBr3 perovskite chemically...
Metal halide perovskites have proven to be excellent light-harvesting materials in photovoltaic devices whose efficiencies are rapidly improving. Here, we examine the temperature-dependent photon absorption, exciton binding energy, and band gap of FAPbI3 (thin film) find remarkably different behavior across β–γ phase transition compared with MAPbI3. While MAPbI3 has shown abrupt changes values for vary smoothly over a range 100–160 K accordance more gradual transition. In addition, that...
Perovskite halides are well-suited to monolithic multijunction photovoltaics, promising low-cost solar-to-electrical power conversion. Critical all-perovskite fabrication is the deposition of a low-bandgap absorber without damaging other device layers. Vapor thus an attractive method, obviating need for optically lossy protective interlayers, but challenging multicomponent perovskites. Here, we demonstrate method dual-source coevaporate perovskite films and devices. We used mixtures formed...
Metal halide perovskite semiconductors have the potential to enable low-cost, flexible, and efficient solar cells for a wide range of applications. Physical vapor deposition by co-evaporation precursors is method that results in very smooth pinhole-free thin films allows excellent control over film thickness composition. However, become industrially scalable, reproducible process high device yields are essential. Unfortunately, date, reproducibility evaporating organic such as methylammonium...
Optimally enhancing the performance of perovskite silicon tandem solar cells comes with accurate identification loss origins in device combination optoelectrical simulations assessing respective efficiency gains to prioritize optimization pathways. Herein, various characterization methods, namely, spectrally resolved photoluminescence (PL), transient‐PL, PL‐based implied open‐circuit voltage (i V OC ) imaging, spectrometric characterization, and Suns‐ measurements are combined quantify...
Monolithic perovskite-based triple junction solar cells have the potential to surpass power conversion efficiency (PCE) limits of single and dual-junction cells.
Following the impressive efficiencies achieved for two‐terminal perovskite/silicon dual–junction solar cells, perovskite/perovskite/silicon triple‐junction cells have now gained attention and are rapidly developing. In a cell, maximizing open‐circuit voltage ( V OC ) is not straightforward as it requires understanding mitigating dominant losses in such complex structure. Herein, high bandgap perovskite top cell first identified main source of loss cell. A multifaceted optimization approach...
Two‐terminal fully textured perovskite silicon tandem solar cells have recently advanced significantly and are quickly moving toward scalable production. While µm‐sized texturing of the cell enables minimizing reflection losses, tuning layer thickness allows optimizing photo‐generated current distribution between subcells, both approaches introduce challenges at development stage. One these is accurate optoelectronic assessment films with photoluminescence (PL) spectroscopy. In this work, we...
Here we present a detailed structural analysis of methylammonium lead halide (I, Cl) films by <italic>in situ</italic> X-ray diffraction during their growth and thermal recrystallization up to decomposition.
Lead halide perovskites are leading candidates for photovoltaic and light-emitting devices, owing to their excellent widely tunable optoelectronic properties. Nanostructure control has been central development, allowing improvements in efficiency stability, changes electronic dimensionality. Recently, formamidinium lead triiodide (FAPbI3) shown exhibit intrinsic quantum confinement effects nominally bulk thin films, apparent through above-bandgap absorption peaks. Here, we show that such...
Abstract Metal halide perovskite semiconductors have shown great performance in solar cells, and including an excess of lead iodide (PbI 2 ) the thin films, either as mesoscopic particles or embedded domains, often leads to improved cell performance. Atomic resolution scanning transmission electron microscope micrographs formamidinium (FAPbI 3 films reveal FAPbI :PbI interface be remarkably coherent. It is demonstrated that such coherence achieved by PbI deviating from its common 2H...
Utilizing thermally evaporated hole transport layers (HTLs) in fully textured perovskite silicon tandem solar cells.
Perovskite‐based triple‐junction solar cells have recently gained significant attention and are rapidly developing, thanks to the insights from advancement in its dual‐junction counterparts. However, employing perovskite materials multijunction with more than two junctions brings new challenges that not yet been addressed. One aspect is possibility of reverse bias breakdown subcells during operation triple–junction device. This relevant for because a higher voltage might drop at compared...
Double‐sided textured silicon solar cells with micrometer‐sized pyramid structure are used as bottom in monolithic tandem structures to decrease reflection losses. As top cell material, frequently perovskites used. In this work, various additives investigated enhance the perovskite absorber quality, a fabricated using hybrid route. context of route, it is found that urea or methylammonium chloride (MACl) can effectively increase grain size and improve while formamidinium (FACl) cannot. With...