Enhancing the efficiency of CdTe thin film solar cells by inserting novel back contact buffer layers

Cadmium telluride (CdTe) polycrystalline thin-films have long been recognized as a leading material in realizing cost effective and reliable photovoltaic (PV) cells. The formation of a stable, low resistance, non-rectifying contact to p-CdTe is one of the major and critical challenges associated with this kind of solar cells. The aim of this work is the systematic investigation of back-contact materials on the performance of CdS/CdTe solar cells. Two novel materials (a) zinc telluride (ZnTe) and (b) antimony telluride (Sb2Te3) as back contact buffer layer have been investigated in this analysis by PC-1D simulator. Moreover, the effect of absorber (CdTe) layer thickness reduction with these materials has also been carried out. All the simulations have been done using PC-1D simulator. Conversion efficiency as high as 12.5% (Voc = 0.59 V, Jsc = 26.6 mA/cm², FF = 0.59) is achieved with 5 ??m-CdTe absorber layer, 50 nm-CdS window layer and ZnTe buffer layer. It has also been found that thinner CdTe layer is possible with the least sacrifice in efficiency.