| 摘要： |
Solution-processed organic-inorganic halide perovskite (OIHP) thin films typically contain fine, randomly oriented grains and a high-density grain-boundary network, which are unfavorable for key film functions including charge transport and environmental stability. Here, we report a new chemical route for achieving CH3NH3PbI3 (MAPbI(3)) OIHP thin films comprising large, uniaxially oriented grains and an ultralow-density grain-boundary network. This route starts with a new metastable liquid-state precursor phase, MAPbI(3)center dot MACl center dot xCH(3)NH(2), which converts to metastable MAPbI(3)center dot MACl and then to MAPbI(3) OIHP upon stepwise release of volatile CH3NH2 and MACl. Perovskite solar cells made via this route show high power conversion efficiency of up to 19.440, with significantly enhanced environmental stability. |
