Advancements in Back Contact Materials for CdTe Solar Cells

Cadmium telluride (CdTe)‐based cells are the leading commercial thin‐film solar cell (TFSC) technology, with recent laboratory efficiency surpassing 22%. There is still a scope for advancing CdTe technology toward the Shockley–Queisser limit of ∼32%. Numerous scientists worldwide have made significant efforts to improve the efficiency of CdTe solar cells. In a CdTe solar cell, the back contact and its optimization play a key role. The parameters related to the back contact include selecting an appropriate material, barrier height, band alignment, back contact buffer layer, etching, and others. We review recent developments in the applications of various materials (metal oxides, graphene oxide, perovskites, etc.) used as back contact and their properties. Additionally, we review the works on controlled p‐type doping in the absorber layer through copper‐based treatments. To provide a comprehensive overview, this review article aims to encompass the most recent theoretical and experimental advancements. Here, an attempt has been made to draw the research community's attention to the wonderful opportunity this TFSC technology offers.