High-Performance and Hysteresis-Free Planar Solar Cells with PC₇₁BM and C₆₀ Composed Structure Prepared Irrespective of Humidity

Perovskite solar cells with excellent photovoltaic performance have drawn enormous attention in the past seven years. However, most perovskite films are processed in a glovebox to isolate oxygen and water, which hampers real applications. In this paper, we report hysteresis-free and high performance planar perovskite devices prepared without an inert atmosphere and irrespective of the humidity. High crystalline CH₃NH₃PbI₃ films were prepared by one-step spin coating with relative humidity (RH) as high as 45%. Electron transport layers formed by C₆₀ and [6,6]-phenyl-C₇₁-butyric acid methyl ester, which could isolate moisture and reduce the series resistance, are introduced into planar perovskite devices. The structure of devices is ITO/PEDOT:PSS/CH₃NH₃PbI₃/PC₇₁BM/C₆₀/BCP/Al. Under optimized conditions, the perovskite devices with the maximum power conversion efficiency (PCE) of 14.08% and an average PCE of 13.50% were obtained. Meanwhile, it is found that the devices showed negligible photocurrent hysteresis, which has been a bottleneck for real applications. The influences of spin-coating speeds and electron transport layers on devices are also discussed in this paper.