Improved open-circuit voltage of CsPbI3 quantum dot solar cells by PMMA interlayer

Abstract All-inorganic CsPbI3 quantum dots perovskite solar cells (QDPSCs) have wide potential application due to their excellent photoelectric properties with high environmental stability. However, the poor interface contact between the light absorption layer and hole transport layer (HTL) results in the serious carrier recombination and the large open-circuit voltage (VOC) loss. Herein, we introduce the insulating PMMA (poly(methyl methacrylate)) buffer layer into CsPbI3 quantum dots (QDs)/Cu12Sb4S13 QDs HTL interface in all-inorganic QDPSCs with the structure of FTO/c-TiO2/m-TiO2/CsPbI3 QDs/Cu12Sb4S13 QDs/Au. The interface carrier recombination is obviously suppressed and the significant VOC improvement from 1.04 V to 1.14 V is obtained with the incorporated PMMA buffer layer. The devices with PMMA buffer layer show the enhanced power conversion efficiency (PCE) of 10.99%, and the improvement of 9.71% is achieved compared to that of the control devices (10.02%). The stability is significantly enhanced due to the intrinsic hydrophobic characteristic of PMMA, and the devices retain 62.69% of their initial PCE after stored in air condition for 15 days, which is greatly improved compared with the control device without PMMA.