An efficient, flexible perovskite solar module exceeding 8% prepared with an ultrafast PbI(2) deposition rate

Large-area, pinhole-free CH(3)NH(3)PbI(3) perovskite thin films were successfully fabricated on 5 cm × 5 cm flexible indium tin oxide coated polyethylene naphthalate (ITO-PEN) substrates through a sequential evaporation/spin-coating deposition method in this research. The influence of the rate-controlled evaporation of PbI(2) films on the quality of the perovskite layer and the final performance of the planar-structured perovskite solar cells were investigated. An ultrafast evaporation rate of 20 Å s(−1) was found to be most beneficial for the conversion of PbI(2) to CH(3)NH(3)PbI(3) perovskite. Based on this high-quality CH(3)NH(3)PbI(3) film, a resultant flexible perovskite solar sub-module (active area of 16 cm(2)) with a power conversion efficiency of more than 8% and a 1.2 cm(2) flexible perovskite solar cell with a power conversion efficiency of 12.7% were obtained.