Metal Halide Perovskites for Light-Harvesting and Quantum Applications
Prof. Laura Herz
Department of Physics
University of Oxford
Organic-inorganic metal halide perovskites have emerged as efficient and versatile semiconductors for a range of uses, including in photovoltaic, light-emitting and quantum applications. Optical probes have been at the forefront of research unravelling the fundamental physics governing these materials and have also been critical tools to address remaining challenges and opportunities relating to material microstructure, ionic migration, stability and toxicity.
This colloquium will first outline the fundamental science governing these materials, examining e.g. mechanisms underpinning charge-carrier mobility and recombination, as well as structural effects and defect formation. Our analysis of intrinsic photophysical parameters opens the promise of targeted material design, based on readily accessible parameters, such as band structure, dimensionality, phonon frequencies and the dielectric function.
We further discuss our use of combinatorial optical probes to address remaining challenges to the implementation of metal halide perovskites in solar cells whose power-conversion efficiencies now exceed 26% for single-junction devices. A range of critical issues are explored, relating to material microstructure, environmental degradation, ionic migration and stable bandgap tuning.
In addition, we highlight the potential of metal halide perovskites for quantum application, exploring effects of electronic quantum confinement on optoelectronic properties. We examine how such quantum effects are governed by the nanostructure of metal halide perovskites, exploring two-dimensional layered materials and quasi-zero-dimensional nanocrystals. We further show that nominally bulk lead iodide perovskites can surprisingly exhibit intrinsic quantum confinement, apparent through peak features in their absorption spectrum, offering the prospects of spontaneous bottom-up nanostructuring.
Finally, the challenges and rewards of discovering and developing new lead-free perovskites and their structural derivatives are outlined.
Hosted by Prof. Janko
Originally published at physics.nd.edu.