From 2D to 3D: a facile and effective procedure for fabrication of planar CH3NH3PbI3perovskite solar cells

2D organic–inorganic hybrid perovskite single crystal (n-C₃H₇NH₃)₆Pb₄I₁₄was synthesized, and converted into 3D CH₃NH₃PbI₃perovskiteviaorganic-cation displacement. Using the film as a light absorber, planar perovskite solar cells were fabricated with the best power conversion efficiency of 19.19%.