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Performance improvement of perovskite solar cells by employing a CdSe quantum dot/PCBM composite as an electron transport layer
Zeng, Xiaofeng1; Zhou, Tingwei1; Leng, Chongqian2; Zang, Zhigang1; Wang, Ming1; Hu, Wei1; Tang, Xiaosheng1; Lu, Shirong2; Fang, Liang3; Zhou, Miao1
AbstractOrganic-inorganic hybrid perovskites have recently attracted considerable interest for application in solar cells due to their low cost, high absorption coefficient and high power conversion efficiency (PCE). Herein, we utilize a CdSe quantum dot/PCBM composite as an electron transport layer (ETL) to investigate the structure, stability and PCE of CH3NH3PbI3-xClx perovskite solar cells. It is found that adsorption of the CdSe/PCBM composite reduces the roughness of the perovskite, leading to a high-quality film with a compact morphology. Density functional theory (DFT) based first-principles calculations show that CdSe enhances the chemical stability of CH3NH3PbI3-xClx involving strong atomic orbital hybridization. Interestingly, an inorganic-terminated perovskite surface has much stronger interaction with CdSe compared to the surface with organic CH3NH3 termination, with noticeable interfacial charge redistribution. Experiments on solar cells incorporating the CdSe/PCBM composite as the ETL show enhanced photocurrent and fill factor, which is related to the in-built electric field between CH3NH3PbI3-xClx and CdSe that greatly facilitates the separation of electron and hole pairs. We show an improved PCE of 13.7% with enhanced device stability in a highly humid atmosphere. These joint theoretical-experimental results may provide a new aspect for improving the structural stability and operating performance of optoelectronic devices based on perovskite structures.
Corresponding AuthorZang, ZG ; Zhou, M (reprint author), Chongqing Univ, Key Lab Optoelect Technol & Syst, Minist Educ, Coll Optoelect Engn, Chongqing 400044, Peoples R China.
Indexed BySCI
WOS IDWOS:000408267300039