A computational analysis to enhance performance of CIGS solar cells using back surface field and ZnSe buffer layer approach

Abstract This study aims to enhance copper indium gallium selenide (CIGS) solar cell efficiency while minimizing environmental impact by replacing the toxic CdS buffer layer with a ZnSe buffer layer. The CIGS chalcogenide semiconductor is a promising solar cell absorber material but has faced challenges related to defect-free manufacturing, misaligned buffer layers, and device configuration. Cuprous oxide (Cu 2 O) and zinc selenide (ZnSe), an inexpensive, eco-friendly, and widely available material, are suggested as a back surface field layer and buffer layer to enhance device performance. This paper proposes a new cadmium-free structure (Al/ZnO:Al/ZnO/ZnSe/CIGS/Cu 2 O/Ni) to enhance the efficiency of CIGS heterojunction solar cells by reducing charge carrier recombination losses. We utilized solar cell capacitance simulator (SCAPS-1D) to simulate photovoltaic (PV) performance and examined the impacts of electron affinity, absorber thickness, interface defect density, operating temperature, radiative recombination coefficient (RRC), Mott–Schottky analysis, parasitic resistance, and quantum efficiency on PV characteristics. Optimization and choosing a suitable buffer and passivation layer gives the device efficiency of 31.13%, followed by V OC (0.92 V), J SC (40.40 mA cm −2 ), and FF (83.34%) for the proposed structure. The RRC found to be 10 −13 cm 3 s −1 and the parasitic resistance of the solar cell are in good agreement for fabricating high-efficiency solar cells. These findings suggest that CIGS-based heterojunction solar cells represent a cutting-edge method for achieving high-efficiency solar cells that outperform earlier designs.