All Antimony Chalcogenide Tandem Solar Cell

摘要

A proof-of-concept tandem solar cell using Sb_2S_3 and Sb_2Se_3 as top and bottom cell absorber materials is demonstrated. The bandgaps of Sb_2S_3 and Sb_2Se_3 are 1.74 and 1.22 eV, perfectly satisfying the requirement of tandem solar cells. The application of few-layer graphene enables high transmittance and excellent interfacial contact in the top subcell. By controlling the thickness of the top cell for maximizing the spectral application, the tandem device delivers a power conversion efficiency of 7.93%, which outperforms the individually optimized top cell (5.58%) and bottom cell (6.50%). Mechanistical investigation shows that the tandem device is able to make up voltage loss in the subcells, which is a critical concern in the current antimony chalcogenide solar cells. This study provides an alternative approach to enhancing the energy conversion efficiency of antimony selenosulfide.