Alloyed (Cu2SnS3)x(ZnS)1−x quantum dots as a hole-transporting layer for efficient and stable perovskite solar cells

Abstract In the present study, alloyed (Cu2SnS3)x(ZnS)1−x quantum dots (QDs) were prepared by combining Cu2SnS3 and ZnS. The alloyed (Cu2SnS3)x(ZnS)1−x was applied to perovskite solar cells (PSCs) as an inorganic hole transport layer. The power conversion efficiency (PCE) of the solar cells based on (Cu2SnS3)x(ZnS)1−x was optimized by tuning the content of ZnS. A high PCE of 17.02% was obtained for the solar cells based on the optimized (Cu2SnS3)0.7(ZnS)0.3 quantum dots, while that of the solar cells based on Cu2SnS3 was 15.96%. The experimental data demonstrate that the enhancement of PCE could be due to the high conductivity of the alloyed (Cu2SnS3)0.7(ZnS)0.3 QDs and suitable energy level alignment between the corresponding QDs and perovskite layer. In addition, the PSCs based on the alloyed (Cu2SnS3)0.7(ZnS)0.3 possess superior stability compared with that of the Cu2SnS3 based devices. This work displays that (Cu2SnS3)0.7(ZnS)0.3 QDs can be used as a novel inorganic hole transport material to PSCs.