Single-Crystal-like Perovskite for High-Performance Solar Cells Using the Effective Merged Annealing Method

We report a simple, low cost, and quite effective method for achieving single-crystal-like CH₃NH₃PbI₃ perovskite leading to a significant enhancement in the performance and stability of inverted planar perovskite solar cells (IPSCs). By employing a merged annealing method during the fabrication of an IPSC for preparing the perovskite CH₃NH₃PbI₃ film, we remarkably increase the crystallinity of the CH₃NH₃PbI₃ film and enhance the device performance and stability. An IPSC with the indium tin oxide/poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate)/CH₃NH₃PbI₃ (active layer)/[6,6]-phenyl-C₆₁-butyric acid methyl ester/Al structure was fabricated using the merged annealing method and exhibited significantly enhanced performance with a high power conversion efficiency of 18.27% and a fill factor of 81.34%. Moreover, since two separate annealing processes are merged in the proposed annealing method, the fabrication step becomes much simpler and easier, leading to a reduction in fabrication costs.