Interfacial Passivation of the p‐Doped Hole‐Transporting Layer Using General Insulating Polymers for High‐Performance Inverted Perovskite Solar Cells

• Published in: Small (Weinheim an der Bergstrasse, Germany) Vol. 14; no. 19; pp. e1704007 - n/a
• Main Authors: Zhang, Fan, Song, Jun, Hu, Rui, Xiang, Yuren, He, Junjie, Hao, Yuying, Lian, Jiarong, Zhang, Bin, Zeng, Pengju, Qu, Junle
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01.05.2018
• Subjects: Carrier recombination; Current leakage; Dopants; Energy conversion efficiency; high efficiency; hysteresis‐free; interfacial passivation; Nanotechnology; Passivity; perovskite solar cells; Photovoltaic cells; polymers; Polymethyl methacrylate; Polystyrene resins; Solar cells; Thickness; high efficiency; interfacial passivation; polymers; hysteresis-free; perovskite solar cells
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.201704007

Organic–inorganic lead halide perovskite solar cells (PVSCs), as a competing technology with traditional inorganic solar cells, have now realized a high power conversion efficiency (PCE) of 22.1%. In PVSCs, interfacial carrier recombination is one of the dominant energy‐loss mechanisms, which also results in the simultaneous loss of potential efficiency. In this work, for planar inverted PVSCs, the carrier recombination is dominated by the dopant concentration in the p‐doped hole transport layers (HTLs), since the F4‐TCNQ dopant induces more charge traps and electronic transmission channels, thus leading to a decrease in open‐circuit voltages (VOC). This issue is efficiently overcome by inserting a thin insulating polymer layer (poly(methyl methacrylate) or polystyrene) as a passivation layer with an appropriate thickness, which allows for increases in the VOC without significantly sacrificing the fill factor. It is believed that the passivation layer attributes to the passivation of interfacial recombination and the suppression of current leakage at the perovskite/HTL interface. By manipulating this interfacial passivation technique, a high PCE of 20.3% is achieved without hysteresis. Consequently, this versatile interfacial passivation methodology is highly useful for further improving the performance of planar inverted PVSCs. A thin insulating polymer layer is inserted in the hole transport layer and perovskite interface to significantly increase the open‐circuit voltage without sacrificing the fill factor, and consequently an average power conversion efficiency of 20.06% is achieved. The passivation layer can lead to the efficient passivation of surface trap states and blocks the electrons transporting into the hole transport layer.