Room-temperature water-vapor annealing for high-performance planar perovskite solar cellsElectronic supplementary information (ESI) available: Normalized UV-vis absorption spectra of the perovskite films with various treatments (Fig. S1), XRD patterns of the perovskite films with various treatments (Fig. S2), SEM images of the perovskite films treated by WVA for various times (Fig. S3), AFM images of the perovskite films with various treatments (Fig. S4 and S5), device parameters with various tr

• Main Authors: Wang, Binbin, Zhang, Zhi-Guo, Ye, Senyun, Rao, Haixia, Bian, Zuqiang, Huang, Chunhui, Li, Yongfang
• Format: Article
• Language: English
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/c6ta08655a

We report here the discovery of a unique room-temperature water-vapor annealing (WVA) method to fabricate high performance planar heterojunction perovskite solar cells (pero-SCs) based on CH 3 NH 3 PbI 3 . High crystallinity and void-free perovskite films were obtained by the WVA treatment at room temperature without thermal annealing (TA) and the power conversion efficiency (PCE) of the pero-SCs reached 16.4% with a high open circuit voltage ( V oc ) of 1 V. A mechanism is proposed that the water vapor molecules catalyzed the dissolution and re-crystallization of the perovskite at the grain edges and void area, resulting in void-free and large sized crystals in the perovskite films and the improved photovoltaic performance. This WVA approach provides a simple, high-efficiency and energy conservation processing method in the fabrication of planar perovskite solar cells towards commercialization. A room-temperature water-vapor annealing method was developed to fabricate high crystallinity and void-free perovskite films, improving their photovoltaic device performance.