Achieving high-efficiency perovskite-based solar cells through engineering hole-transport layer

Abstract

Perovskite solar cells (PSCs) based on Quantum dot hole transporting layers (QD-HTLs) have been widely studied recently. However, although the QD-HTLs have proved their potential in PSCs, it remains a big challenge to enhance the hole mobilities of QD-HTLs while maintaining their stability. Based on the extracted results of this research, we demonstrate that introducing CuInS2 QDs as HTMs result in remarkably improved performance of PSCs. After improving the preparation process, QD interlayers are provided with a high-quality perovskite thin film by passivating the perovskite surface. The perovskite film has 16.34 nm surface roughness which is low, and it obviously has clear grain boundaries. For fabricated PSCs, the Photoelectric conversion efficiency (PCE) is remarkably enhanced so that its value increased from 3.25% to 14.22%. Consequently, CuInS2 QDs are utilized at an optimum concentration along with superficial ligands as hole transport materials, which control the shape and the size of the CuInS2s and shows favourable effects on the performance of the perovskite-based solar cell. We also study the CuInS2 QD/perovskite interface in order to consider the carrier dynamic transportation behaviour, in which the results are increasing the photobleaching recovery rate and quenching the fluorescence. Finally, we demonstrate that for fabricating PSCs, the CuInS2 QDs are one of the most promising inorganic QDs with a role of HTMs in the structure of PSCs.