All-inorganic Sb2S3-based Two-terminal Tandem Solar Cells Enable over 10.9% Efficiency Employing a Concise Interconnection Layer

Abstract

Tandem solar cells (TSCs) present a prospective avenue to surpass the theoretical efficiency limits of single-junction solar cells (SJSCs). Antimony sulfide (Sb2S3), a 1.7 eV bandgap semiconductor, holds high potential to serve as the top-cell absorber for TSC. Up to now, there is little Sb2S3 two-terminal (2T) TSC report due to the limit of hole transport layer (HTL) and interconnection layer. Herein, we succeed to implement Sb2S3-based 2T-TSCs with the assistance of lead sulfide quantum dot (PbS QD) rear cells. Firstly, by screening the HTL as 1,2-ethanedithiol capped quantum dots, the power conversion efficiency (PCE) of the Sb2S3 SJSC reaches 7.82%, top value among all-inorganic Sb2S3 SC reports. More importantly, an efficient Au recombination layer is developed to bridge the two subcells and obtain the summation of the subcell open-circuit voltages (1.128 V) with a minimal voltage loss ~0.8%. After the modulation of subcell absorber thickness by optical simulation and device investigation, the champion device meets the photocurrent matching and its 2T-TSC PCE reaches 10.92%, the highest reported value among Sb2S3-based TSCs. Our work opens the door for Sb2S3 based 2T-TSCs, and is expected to trigger the hot research interest for new conception TSCs.