Comprehensive study on CdSe thin film as potential window layer on CdTe solar cell by SCAPD-1D

Abstract

Photovoltaics significantly contributes towards the emerging renewable energy drive. Amongst the available thin film solar cell technologies, presently CdTe is leading at commercial state. CdS is being widely used as window layer in CdTe solar cell but challenged with toxicity. Therefore, this project explores the feasibility of CdSe as alternative window layer in CdTe solar cell. The CdSe is optimized to determine the best complete CdTe based solar cell. The study also compares the device performance of proposed CdSe/CdTeSe/CdTe solar cell with other reported CdSe/CdTe and CdS/CdSe solar cells. While degerming the optimized thickness of CdTe solar cell with respect to different prospective window layer materials, the simulation results reveal that CdTe thickness can significantly reduce, at least by 500 nm, with only 1% reduction in PCE by replacing conventional CdS window layer with CdSe layer. Furthermore, while determining the appropriate Se composition on CdSexTe1-x as this layer forms between CdTe and CdSe layer during the fabrication, it has been found that 18% efficiency can be obtained in CdTe solar cell if the stoichiometry of CdSexTe1-x can be maintained as CdSe0.3Te0.7 during the device fabrication.