A5016005909- Perovskite Materials and Applications
- Solid-state spectroscopy and crystallography
- Magnetic and transport properties of perovskites and related materials
- Optical properties and cooling technologies in crystalline materials
- Chalcogenide Semiconductor Thin Films
- Thermal Expansion and Ionic Conductivity
- Quantum Dots Synthesis And Properties
- 2D Materials and Applications
- Ferroelectric and Piezoelectric Materials
- Microwave Dielectric Ceramics Synthesis
University of California, San Diego
2022-2025
The light-emitting diodes (LEDs) used in indoor testing of perovskite solar cells do not expose them to the levels ultraviolet (UV) radiation that they would receive actual outdoor use. We report degradation mechanisms p-i-n-structured under unfiltered sunlight and with LEDs. Weak chemical bonding between perovskites polymer hole-transporting materials (HTMs) transparent conducting oxides (TCOs) dominate accelerated A-site cation migration, rather than direct HTMs. An aromatic phosphonic...
We present a design strategy for fabricating ultrastable phase-pure films of formamidinium lead iodide (FAPbI 3 ) by lattice templating using specific two-dimensional (2D) perovskites with FA as the cage cation. When pure FAPbI precursor solution is brought in contact 2D perovskite, black phase forms preferentially at 100°C, much lower than standard annealing temperature 150°C. X-ray diffraction and optical spectroscopy suggest that resulting film compresses slightly to acquire (011)...
The halide perovskite formamidinium lead iodide (FAPbI3) is a prime candidate for photovoltaics due to its excellent optoelectronic properties, but application has been limited structural instability. large size of the FA cation results in metastability photoactive cubic phase and facile degradation into thermodynamically stable hexagonal phases at room temperature. Recently, incorporation two-dimensional (2D) Ruddlesden–Popper seeds FAPbI3 precursor solution was shown template growth...
Metal halide perovskites (MHPs) have a strong potential for optoelectronic applications, especially photovoltaics. A significant advantage offered by MHPs is their bandgap tunability via chemical substitution and alloying, with lead–tin alloys producing the narrowest reported bandgaps of ∼1.2 eV. Efforts to further narrow alloying in other elements, such as bismuth, largely been unsuccessful due introduction defective electronic states, which severely diminish quality. In this study, we...
Abstract Understanding the optoelectronic properties of optically active materials at nanoscale often proves challenging due to diffraction-limited resolution visible light probes and dose sensitivity many high-energy electron probes. In this study, we demonstrate correlative synchrotron-based scanning x-ray excited optical luminescence (XEOL) fluorescence (XRF) simultaneously probe local composition halide perovskite thin films interest for photovoltaic devices. We find that XEOL stability,...
The inorganic perovskite CsPbI3 shows promising photophysical properties for a range of potential optoelectronic applications but is metastable at room temperature. To address this, Br can be alloyed into the X-site to create compositions such as CsPbI2Br that are stable temperature have bandgaps >1.9 eV - severely limiting solar applications. Herein, in an effort achieve phase films with <1.85 eV, we investigate alloying chlorine iodine-rich triple-halide CsPb(I0.8Br0.2-x Cl x )3 0 < 0.1....
Longer-chained alkylammonium chlorides can decrease perovskite solution degradation rates and increase light/heat stability of FAPbI 3 films.