Zinc Chloride‐Treated Indium Sulfide as Buffer Layer for Cd‐Free Antimony Selenide Solar Cells
Yizhe Dong, Lei Huang, Haolin Wang, Xiaoqi Peng, Yan Wang, Rongfeng Tang, Changfei Zhu, Tao Chen
Abstract
In 2 S 3 , as a promising environmentally benign semiconductor, is used as a buffer layer in thin‐film solar cells due to its high electron mobility, low toxicity, and excellent thermal and chemical stability. The preparation of a high‐quality In 2 S 3 film is crucial for the improvement of its carrier extraction ability and subsequent deposition of absorber layers. Herein, it is demonstrated for the first time that a posttreatment of In 2 S 3 film with ZnCl 2 solution is able to serve as buffer layer for constructing superstrate Sb 2 Se 3 solar cells. The posttreatment with ZnCl 2 not only prevents In 2 S 3 from excessive oxidation during annealing process, but also facilitates the growth of (hk1) orientation of Sb 2 Se 3 , thereby improving the interfacial contact of In 2 S 3 /Sb 2 Se 3 . The improved heterojunction quality suppresses the carrier recombination at the interface, and enhances the charge extraction ability of In 2 S 3 . As a result, the power conversion efficiency of Sb 2 Se 3 solar cell increases from 2.63% to 5.00%. Herein, a facile and effective strategy is provided for the application of In 2 S 3 as the buffer layer in inorganic chalcogenide solar cells.