Computational Design of Dopants in CdTe Grain Boundaries for Efficient Photovoltaics

A fundamental understanding of the role of dopants in electronic structure of polycrystalline CdTe may lead to efficiency improvements. In the present work, we investigated effect of Cl, P and S doping on CdTe grain boundaries using first principles density functional theory (DFT) calculations. In addition to already known Cl, P and S can segregate in grain boundaries and incorporation of these elements can effectively reduce midgap states to increase the photovoltaic efficiency of CdTe. The methodology we presented can be used to design other alloying elements to CdTe to improve photovoltaic efficiency towards reaching the theoretical limit.