A5003779391- Perovskite Materials and Applications
- Conducting polymers and applications
- Quantum Dots Synthesis And Properties
- Chalcogenide Semiconductor Thin Films
- Solid-state spectroscopy and crystallography
- Organic Light-Emitting Diodes Research
- Polyoxometalates: Synthesis and Applications
- Advanced Nanomaterials in Catalysis
- Advanced Photocatalysis Techniques
- Organic Electronics and Photovoltaics
- TiO2 Photocatalysis and Solar Cells
- Geometric Analysis and Curvature Flows
- Advanced Differential Geometry Research
- Layered Double Hydroxides Synthesis and Applications
- Mathematics and Applications
- Point processes and geometric inequalities
- Advancements in Battery Materials
- Crystallization and Solubility Studies
- 2D Materials and Applications
- Magnetic Properties and Synthesis of Ferrites
- Thermal Expansion and Ionic Conductivity
- Plasmonic and Surface Plasmon Research
- Optical Coatings and Gratings
- X-ray Diffraction in Crystallography
- Advanced Battery Materials and Technologies
École Polytechnique Fédérale de Lausanne
2019-2023
University of Lausanne
2020
Delft University of Technology
2018
University of Colorado Boulder
2012-2013
University of Colorado System
2012
Moving a perovskite into the black The bandgap of α-phase FAPbI 3 (where FA is formamidinium) nearly ideal for solar cells, but it unstable with respect to photoinactive yellow δ-phase. Lu et al. found that film phase was converted highly crystalline by vapor exposure methylammonium thiocyanate at 100°C, and retained this structure after 500 hours 85°C. Solar cells fabricated material had power conversion efficiency more than 23%. After under maximum tracking period dark recovery, 94%...
Passivation of interfacial defects serves as an effective means to realize highly efficient and stable perovskite solar cells (PSCs). However, most molecular modulators currently used mitigate such form poorly conductive aggregates at the interface with charge collection layer, impeding extraction photogenerated carriers. Here, a judiciously engineered passivator, 4-tert-butyl-benzylammonium iodide (tBBAI), is introduced, whose bulky tert-butyl groups prevent unwanted aggregation by steric...
High-quality perovskite light harvesters and robust organic hole extraction layers are essential for achieving high-performing solar cells (PSCs). We introduce a phosphonic acid-functionalized fullerene derivative in mixed-cation perovskites as grain boundary modulator to consolidate the crystal structure, which enhances tolerance of film against illumination, heat, moisture. also developed redox-active radical polymer, poly(oxoammonium salt), that can effectively p-dope hole-transporting...
Abstract Dye‐sensitized solar cells (DSSCs) based on Cu II/I bipyridyl or phenanthroline complexes as redox shuttles have achieved very high open‐circuit voltages ( V OC , more than 1 V). However, their short‐circuit photocurrent density J SC ) has remained modest. Increasing the is expected to extend spectral response of sensitizers red NIR region while maintaining efficient electron injection in mesoscopic TiO 2 film and fast regeneration by I complex. Herein, we report two new...
The use of layered perovskites is an important strategy to improve the stability hybrid perovskite materials and their optoelectronic devices. However, tailoring properties requires accurate structure determination at atomic scale, which a challenge for conventional diffraction-based techniques. We demonstrate nuclear magnetic resonance (NMR) crystallography in determining mixed-spacer model composed 2-phenylethylammonium (PEA+) 2-(perfluorophenyl)ethylammonium (FEA+) moieties, revealing...
Metal halide perovskites (MHPs) have shown an incredible increase in efficiency, reaching as high 25.7%, which now competes with traditional photovoltaic technologies. Herein, we excluded CsX and RbX (X = I–, Br–, Cl–), the most commonly used cations to stabilize α-FAPbI3, from bulk of perovskite thin films applied them on surface passivation agents. Extensive device optimization led a power conversion efficiency (PCE) 24.1% fill factor (FF) 82.2% upon CsI. We investigated depth effect CsI...
The most efficient and stable perovskite solar cells (PSCs) are made from a complex mixture of precursors. Typically, to then form thin film, an extreme oversaturation the precursor is initiated trigger nucleation sites, e.g., by vacuum, airstream, or so-called antisolvent. Unfortunately, triggers do not expel lingering (and highly coordinating) dimethyl sulfoxide (DMSO), which used as solvent, films; this detrimentally affects long-term stability. In work, (the green) sulfide (DMS)...
Abstract Layered hybrid perovskites have emerged as a promising alternative to stabilizing organic–inorganic perovskite materials, which are predominantly based on Ruddlesden‐Popper structures. Formamidinium (FA)‐based Dion‐Jacobson analogs developed that feature bifunctional organic spacers separating the slabs by introducing 1,4‐phenylenedimethanammonium (PDMA) moieties. While these materials demonstrate competitive performances compared other FA‐based low‐dimensional solar cells,...
Abstract In all kinds of solar cells, transient photovoltage (TPV) decay measurements have been used to determine charge carrier lifetimes and quantify recombination processes orders. However, in particular, for thin‐film devices with a high capacitance, the time constants observed common TPV do not describe dynamics but RC ( R : resistance, C capacitance) times charging electrodes. This issue has revisited organic perovskite cells recent literature. Here, these discussions are extended by...
Various approaches have been employed to passivate the defects in perovskite films used solar cells (PSCs). However, passivation mechanism is often unclear at a molecular level, and reason for enhanced PSC performance remains elusive. Here, we explore impact of with high-work-function two-dimensional (2D) perovskites promoting efficiency PSCs. We realized that 4-halophenylethylammonium lead iodide possesses high work function, causing band bending surface, thus suppressing charge carrier...
Abstract Dye‐sensitized solar cells (DSSCs) based on Cu II/I bipyridyl or phenanthroline complexes as redox shuttles have achieved very high open‐circuit voltages ( V OC , more than 1 V). However, their short‐circuit photocurrent density J SC ) has remained modest. Increasing the is expected to extend spectral response of sensitizers red NIR region while maintaining efficient electron injection in mesoscopic TiO 2 film and fast regeneration by I complex. Herein, we report two new...
Abstract Four ZnPc‐dimers with 2,5‐thienyl (ZnPc−th−ZnPc 1 ), 2,7‐fluorenyl (ZnPc−flu−ZnPc 2 3,6‐bisthienylldiketopyrrolopyrrole (ZnPc−DPP−ZnPc 3 ) and 1,4‐phenyl (ZnPc−p−ZnPc 4 bridges have been studied as dopant‐free hole transporting materials (HTMs) in perovskite solar cells (PSCs). The synthesis characterization of ZnPc−th−ZnPc ZnPc−flu−ZnPc dimers are reported for the first time. Steady state time resolved photoluminescence demonstrate good hole‐extraction capability these materials....
Structural properties and photophysics of layered perovskites comprising adamantyl (A) cations in A<sub>2</sub>FA<sub>n−1</sub>Pb<italic>n</italic>I<sub>3n+1</sub> (<italic>n</italic> = 1–3, FA formamidinium) composition are studied by a combination theoretical experimental techniques to unravel unique features.
The main challenge of sodium-ion batteries is cycling stability, which usually compromised due to strain induced by sodium insertion. Reliable high-voltage cathode materials are needed compensate the generally lower operating voltages Na-ion compared Li-ion ones. Herein, density functional theory (DFT) computations were used evaluate thermodynamic, structural, and kinetic properties high voltage λ-Mn2O4 λ-Mn1.5Ni0.5O4 spinel structures as for batteries. Determination enthalpies formation...
Two-dimensional (2D) hybrid perovskite solar cells have induced widespread research interest owing to their higher stability as compared three-dimensional (3D) analogues. The photovoltaic performance, however, is still limited. Here, we report a film dominated by 3D components that are modulated formamidinium thiocyanate in the 2D PEA2FA3Pb4I13 composition. We demonstrate dimensionality transformation from 2D/3D predominantly phase presence of SCN-based treatment enhances optical absorption...
In this work, we describe a new class of non-fused 3D asymmetric compounds (named 1, 2, 3, and 4) as low-cost organic hole-transporting materials (HTMs) for perovskite solar cells (PSCs). The fundamental understanding the influence methylthio methoxy group substitutions on fluorene moiety has been analyzed, well position groups in aromatic rings triphenylamine pending (para or meta). Experimental results demonstrate that influences decisively thermal properties amplitude electronic bandgap,...
Two hundred sixty-six films processed with flash infrared annealing were optically and structurally characterized. We determine the optimum conditions for formation of mixed-cations halide perovskite active phase.
Metal halide perovskites (MHPs) have shown an incredible rise in efficiency, reaching as high 25.7%, which now competes with traditional photovoltaic technologies. Herein, we excluded CsX and RbX, the most commonly used cations to stabilize FAPbI3, from bulk of perovskite thin films applied them on surface, passivation agents. Extensive device optimization led a power conversion efficiency (PCE) 24.1% fill factor (FF) 82.2% upon CsI. We investigated in-depth effect CsI structural...