All-inorganic Sb₂S₃-based two-terminal tandem solar cells enable over 10.9% efficiency employing a concise interconnection layer

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 TSCs. Up to now, there are few reports on Sb₂S₃ two-terminal (2T) TSCs due to the limit of the hole transport layer (HTL) and interconnection layer. Herein, we succeed in implementing Sb₂S₃-based 2T-TSCs with the assistance of lead sulfide quantum dot (PbS QD) rear cells. Firstly, by using the 1,2-ethanedithiol capped quantum dots as HTL, the power conversion efficiency (PCE) of the Sb₂S₃ SJSC reaches 7.82%, a 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 rate of ∼0.8%. After the modulation of the subcell absorber thickness by optical simulation and device investigation, the champion device achieves 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 all-inorganic antimony-based TSCs. © 2024 The Royal Society of Chemistry.