Novel 2D material from AMQS-based defect engineering for efficient and stable organic solar cells

Abstract

In this work, soluble two-dimensional (2D) material of antimonene quantum sheets (AMQSs) is used to form a bilayer hole extraction layer (HEL) with CuSCN. It proves that the application of AMQSs helps to passivate surface defects of CuSCN, resulting in diminished recombination loss and depressed exciton quenching effect, and thereby achieving improved photovoltaic performance. In OPVs based on poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b;4,5-b′]dithiophene-2,6-diyl-alt-(4-(2-ethylhexyl)-3-fluorothieno[3,4-b]thiophene-)-2-carboxylate-2-6-diyl)]: [6,6]-phenyl C71-butyric acid methyl ester (PTB7-Th:PC71BM), over 12% enhancement of power conversion efficiency (PCE) is observed compared to that of the reference cell fabricated with pure CuSCN as an HEL. The advantage of the bilayer CuSCN/AMQS HEL is also confirmed in non-fullerene systems of PBDB-T-2F:IT-4F and PTB7-Th:ITIC. In a cell based on PBDB-T-2F:IT-4F, a PCE of 10.14% was obtained after application of AMQSs, which improved by about 10% compared to that of the reference cell using pure CuSCN as an HEL. Furthermore, cells based on CuSCN and CuSCN/AMQS HEL exhibit superior air stability. The use of a bilayer CuSCN/AMQS HEL provides a promising approach to obtain efficient and stable organic solar cells.