Efficient inverted perovskite solar cells with preferential orientation and suppressed defects of methylammonium lead iodide by introduction of phenothiazine as additive

Publication date: 15 May 2020Source: Journal of Alloys and Compounds, Volume 823Author(s): Yukun Wu, Yue He, Shiqi Li, Xiaoyan Li, Yifan Liu, Qinjun Sun, Yanxia Cui, Yuying Hao, Yucheng WuAbstractHigh crystalline quality of perovskite thin film is essential for efficient metal halide perovskite solar cells (PSCs). In this investigation, we report a simple anti-solvent washing treatment using a versatile electron-rich heterocycle (phenothiazine, PTZ) as additive in sec-butyl alcohol to improve methylammonium lead iodide (MAPbI3) perovskite crystal growth. As a result, the PTZ-modified PSCs exhibit average power conversion efficiency (PCE) of 15.50%, obviously surpassing 14.38% of the reference device, which is due to the synergistic effects of the PTZ on the crystallization orientation and defects passivation of the perovskite films. The strong interaction between PTZ and Pb2+ ions not only promotes the size of the MAPbI3 crystals to increase from 0.58 μm to 0.73 μm and thus reduces the grain boundaries, is but also beneficial for the formation of a preferential orientation perovskite film, thereby delivering improved electronic properties. Moreover, as Lewis base, PTZ passivates the defects among perovskite crystals consistent with the decreased defect density calculated using the space charge limited current (SCLC) method. The result indicates using PTZ as additive into the perovskite precursor solution a highly effective and facile method to obtain high performance PSCs...
Source: Journal of Alloys and Compounds - Category: Chemistry Source Type: research