Reactive close-spaced sublimation processed CuSbSe2 thin films and their photovoltaic application

摘要

CuSbSe₂ is a promising absorber material for thin film solar cells because of its chemistry similarity to the well-known CuInSe₂ but with low-cost and earth abundant component. Various methods have been employed to fabricate CuSbSe₂ thin films with the best photovoltaic device achieving nearly 5% efficiency. Here, we develop a reactive close-spaced sublimation method to prepare high quality CuSbSe₂ films via one evaporation process. In this method, a Cu layer is pre-sputtered onto the substrate, then reacts with Sb₂Se₃ vapor and its decomposition product Se, and finally generates single-phased CuSbSe₂ films with large grains and proper doping density. This new strategy not only suppresses the decomposition of ternary chalcogenide CuSbSe₂ but also is simple and applicable to other ternary semiconductors. Finally, based on this method, we have built prototype solar cells with a structure of AZO/CuSbSe₂/CdS/i-ZnO/ZnO:Al/Au and obtained 3.04% power conversion efficiency for the champion device.