Advancements in CdTe Thin-Film Solar Cells: Is Doping an Effective Strategy for Performance Enhancement?

Abstract

Cadmium telluride (CdTe) thin-film solar cells that are introduced in 1970s have emerged as one of the forefront materials of the second generation-based solar cells. They are preferred as an ideal candidate for the fabrication of reliable and economical photovoltaic systems owing to high optical absorption coefficient, nearly optimum bandgap for ensuring maximum conversion efficiency and chemical stability. The major challenges associated with these solar cells are low concentration of carriers, which limits the photovoltaic parameters notably the open-circuit voltage and fill factor as well as short life time of absorber minority carriers. This article explores the pivotal role of doping in enhancing the electrical properties and life time of minority carriers of CdTe solar cells through extensive literature study of the complexity of mechanisms and output parameters achieved in various reported works. Doping has been systematically reviewed with emphasis on types of doping, classification of dopants into group I and group V dopants along with a concise summary of different dopants. This comprehensive review not only evaluates the recent advancements of CdTe solar cells but also addresses these issues and provides future perspectives and paves way for development of improved stable and highly efficient cells.