Sputtered and selenized Sb2Se3 thin-film solar cells with open-circuit voltage exceeding 500 mV

Abstract

Antimony selenide (Sb 2 Se 3 ) is a potential absorber material for environment-friendly and cost-efficient photovoltaics and has achieved considerable progress in recent years. However, the severe open-circuit voltage ( V oc ) deficit ascribed to the interface and/or bulk defect states has become the main obstacle for further efficiency improvement. In this work, Sb 2 Se 3 absorber layer was prepared by an effective combination reaction involving sputtered and selenized Sb precursor thin films. The self-assembled growth of Sb 2 Se 3 thin films with large crystal grains, benign preferential orientation, and accurate chemical composition were successfully fulfilled under an appropriate thickness of Sb precursor and an optimized selenization scenario. Substrate structured Sb 2 Se 3 thin-film solar cells, a champion device with a power-conversion efficiency of 6.84%, were fabricated. This device is comparable to state-of-the-art ones and represents the highest efficiency of sputtered Sb 2 Se 3 solar cells. Importantly, the high V oc of 504 mV is closely related to the reduced deep level defect density for the Sb 2 Se 3 absorber layer, the passivated interfacial defects for Sb 2 Se 3 /CdS heterojunction interface, and the additional heterojunction heat treatment-induced Cd and S inter-diffusion. This significantly improved V oc demonstrates remarkable potential to broaden its scope of applications for Sb 2 Se 3 solar cells. • An effective combination reaction of sputtered and selenized Sb precursors for Sb 2 Se 3 thin film solar cells. • The self-assembled growth of Sb 2 Se 3 thin films with large crystal grains, benign preferential orientation and accurate chemical composition. • A highly interesting V oc record of 504 mV obtained due to the reduced deep level defect density, the passivated interfacial defects and heterojunction heat treatment-induced Cd and S inter-diffusion. • PCE of 6.84% represents the highest efficiency of sputtered Sb 2 Se 3 solar cells.