Density functional theory modeling of twin boundaries in CdTe as informed by STEM observations

CdTe is one of the most promising photovoltaic materials, currently second only to Si in market share. However, the practical efficiencies of CdTe photovoltaic cells are still significantly below the theoretical limit, indicating possible room for improvement. One aspect in which a fundamental understanding may lead to efficiency improvements is grain boundaries. Atomistic-level characterization, including microscopy and first principles modeling, is crucial in developing such a fundamental understanding.