Perspective on defect control in semiconductors for photovoltaics

Harnessing the boundless solar energy, photovoltaic cells emerge as pivotal players in the world's sustainable energy landscape. The efficiency of solar cells is intimately tied to the carrier properties influenced by defects and impurities within the sunlight-absorbing semiconductors. In this Perspective, we offer a brief overview of recent advances in exploring doping properties with a focus on three vital thin-film photovoltaic semiconductors: CdTe, CIGS, and halide perovskites. Our discourse encompasses their electronic band structure, intrinsic and extrinsic doping behaviors, defect-assisted nonradiative recombination losses, as well as promising strategies poised to enhance solar cell efficiency. Additionally, we discuss several lingering challenges associated with defects in the advancement of photovoltaic technologies.