Improved Efficiency and Carrier Dynamics Transportation Behavior in Perovskite Solar Cells with CuInS2 Quantum Dots as Hole-Transport Materials

Inorganic quantum dot (QD)-based hole-transport materials (HTMs) have proved their potential in perovskite solar cells (PSCs). In this work, CuInS2 quantum dots (CIS QDs) were applied as HTMs for PSCs with the architecture of TiO2/Cs0.17FA0.83Pb(Br0.2I0.8)3/HTM/Au. By optimizing the preparation process, a high-quality perovskite thin film could be obtained. When the speed was 5000 rpm, the speed acceleration was 3000 rpm per s and heat treated at 150 °C, the perovskite film had low surface roughness (15.26 nm) and obvious grain boundary. The photoelectric conversion efficiency (PCE) of PSCs was greatly improved from 2.83% to 12.33% utilizing CIS QDs at an optimal concentration and with surface ligands as HTMs. Surface ligands can control the size and shape of CIS QDs, and thus affect the performance of PSCs. The carrier dynamic transportation behaviour at the CIS/perovskite interface was studied, which showed that CIS QDs as HTMs in PSCs can strongly quench the fluorescence and increase the photobleaching recovery rate. Therefore, CIS QDs are promising inorganic HTMs for the fabrication of PSCs.