Strong Chelating Additive and Modified Electron Transport Layer for 8.26%‐Efficient Sb2S3 Solar Cells

Abstract Antimony sulfide (Sb 2 S 3 ) is a promising absorber for single‐junction and tandem solar cells. Unfortunately, its quasi‐1D structure holds large void space and complex deep defects, which prepare high‐quality absorber layers and pose a significant challenge. In this work, ethylenediaminetetraacetic acid disodium salt (EDTA‐2Na) is developed as an additive to regulate the reaction kinetics for Sb 2 S 3 deposition. The strong chelating interaction between EDTA‐2Na and Sb 3+ significantly suppresses homogeneous nucleation byproducts and retards the deposition rate of the absorber layer. On the other hand, the SnO 2 /CdS double buffer layers could enhance light transmittance, and herein NH 4 F is successfully applied to improve the dispersion of SnO 2 nanoparticles and increase the n‐type conductivity of SnO 2 film through fluorine doping. Finally, the resulting Sb 2 S 3 solar cells obtained significantly improved fill factor (FF) and short circuit current density ( J SC ) values of 64.81% and 17.91 mA cm −2 , and its power conversion efficiency (PCE) reached a new record value of 8.26% (8.08% certified). This work offers new insights into addressing key challenges that hinder the development of Sb 2 S 3 solar cells.