Perovskite halides have emerged as highly promising and efficient materials for photovoltaics and other optoelectronic applications. The progress in this area, however, is made mostly on Pb halides (e.g., MAPbI3) because of the focus on photovoltaics. Our group is interested in halides of different metals and their functional properties such as optical, magnetic, and ferroic. On this front, we strive to discover new perovskite halides, perovskite-inspired materials, hybrid 2-dimensional perovskites, and polar halide materials (a few structure types are shown in the Figure below). We aim for developing synthetic protocols, determining structures, and understanding the links between chemically and structurally different kinds of halide perovskite, and their properties. We also aim to understand how spin-orbit interactions (SOC) impact the optical and magnetic properties of metal halides comprising heavier transition metals such as Mo, Ru, Re, Os, Ir and Au (spin-orbit interactions have significant consequences in the exotic physics of quantum materials, topological insulators, spintronics, and so on). Furthermore, we dig into knowing the effect of chemical environment (ligands) around metal on it’s SOC.
We synthesize single-crystalline and polycrystalline materials via soft chemical (Chimie douce) routes; solvothermal, ordinary solution phase, Schlenk-line methods as well as solid-state syntheses, and determine their structures using single-crystal and powder x-ray diffraction data. We carry out various measurements including optical absorption, emission, electrochemistry and magnetism to understand the properties that we are interested in.
P. Vishnoi, R. Seshadri, and A. K. Cheetham, Why are Double Perovskite Iodides so Rare?, J. Phys. Chem. C, 2021, 125, 11756-11764.
P. Vishnoi, J. L. Zuo, J. A. Cooley, L. Kautzsch, A. Gómez‐Torres, J. Murillo, S. Fortier, S. D. Wilson, R. Seshadri, A. K. Cheetham, Chemical Control of Spin-Orbit Coupling and Charge Transfer in Vacancy-Ordered Ru(IV) Halide Perovskites, Angew. Chem. Int. Ed., 2021, 60, 5184–5188.
P. Vishnoi, J. L. Zuo, T. A. Strom, G. Wu, S. D. Wilson, R. Seshadri, A. K. Cheetham, Structural Diversity and Magnetic Properties of Hybrid Ruthenium Halide Perovskites and Related Compounds, Angew. Chem. Int. Ed., 2020, 59, 8974-8981.
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