InCl3-modified In2O3/CdS double electron transport layers for high-performance Sb2(S, Se)3 solar cell

Antimony selenosulfide [Sb2(S, Se)3] solar cells have attracted increasing attention because of their abundant reserves and excellent photoelectric properties. In the case of the Sb2(S, Se)3 solar cell featuring a superstrate structure of indium tin oxide/cadmium sulfide (CdS)/Sb2(S, Se)3/spiro-OMeTAD/Au, the device performance was limited by the poor heterojunction interfaces, especially the poor interface of the P-N heterojunction. In this study, InCl3-modified In2O3 was used to tailor the quality of the P-N heterojunction. The quality of the CdS deposited on InCl3-modified In2O3 was significantly improved. In addition, the conduction band offset between P-N junctions is tailored, which is helpful for carrier transport. As Sb2(S, Se)3 was deposited on such a modified electron transport layer by InCl3-modified In2O3, the (hkl, l = 1) preferred orientation of the Sb2(S, Se)3 film increased greatly, and the built-in voltage of the Sb2(S, Se)3 solar cell tailored by InCl3-modified In2O3 was enlarged, which is beneficial for carrier transport. Finally, the InCl3-modified In2O3-assisted CdS double electron transport layers achieved a remarkable power conversion efficiency of 7.44% for Sb2(S, Se)3 solar cells via the vapor transport deposition method. This work provides a valuable reference for interface modifications and further boosts the efficiency of Sb2(S, Se)3 solar cells.