Unveiling the Roles of Defects in Photovoltaic Materials through Multiscale Modeling

Abstract

This dissertation develops an integrated multiscale modeling framework for photovoltaic systems, encompassing halide perovskites, cadmium telluride (CdTe), and cadmium selenide (CdSe)–based absorbers. By coupling first-principles density functional theory (DFT) with continuum-scale device simulations, the approach enables quantitative prediction of key electronic and optical properties, as well as the performance limits of complete solar cell architectures. Atomistic DFT calculations provide accurate defect energetics, charge transition levels, and carrier capture coefficients, which are seamlessly incorporated into drift–diffusion device models to resolve carrier transport, recombination, and light–matter interactions under realistic operating conditions. This multiscale methodology allows for systematic evaluation of performance bottlenecks—such as radiative vs. nonradiative loss pathways and loss of open-circuit voltage due to potential fluctuations—and supports the targeted optimization of materials and device structures. The resulting predictive capability offers a transferable framework for guiding experimental design and accelerating the development of next-generation high-efficiency, stable photovoltaic technologies.