In Situ Back-Contact Passivation Improves Photovoltage and Fill Factor in Perovskite Solar Cells
Furui Tan, Hairen Tan,* Makhsud I. Saidaminov, Mingyang Wei, Mengxia Liu, Anyi Mei, Peicheng Li, Bowen Zhang, Chih-Shan Tan, Xiwen Gong, Yongbiao Zhao, Ahmad R. Kirmani, Ziru Huang, James Z. Fan, Rafael Quintero-Bermudez, Junghwan Kim, Yicheng Zhao, Oleksandr Voznyy, Yueyue Gao, Feng Zhang, Lee J. Richter, Zheng-Hong Lu, Weifeng Zhang,* and Edward H. Sargent*
Adv. Mater.31(2019)1807435
Organic-inorganic hybrid perovskite solar cells (PSCs) have seen a rapid rise in power conversion efficiencies in recentyears; however, they still suffer from interfacial recombination and charge extraction losses at interfaces between the perovskite absorber and the charge-transport layers. Here, in situ backcontact passivation (BCP) that reduces interfacial and extraction losses between the perovskite absorber and the hole transport layer (HTL) is reported. A thin layer of nondopedsemiconducting polymer at the perovskite/HTL interface is introduced and it is shown that the use of the semiconductor polymer permits—in contrast with previously studied insulator-based passivants-the use of a relatively thick passivating layer. It is shown that a flat-band alignment between the perovskite and polymer passivation layers achieves a high photovoltage and fill factor: the resultant BCP enables a photovoltage of 1.15 V and a fill factor of 83% in 1.53 eV bandgap PSCs, leading to an efficiency of 21.6% in planar solar cells.
