Appraisement of crystal expansion in CH3NH3PbI3 on doping: improved photovoltaics properties

Three-dimensional hybrid perovskite materials (CH₃NH₃PbI₃) suffer from intrinsic instability due to organic cation evaporation and ion migration. The inclusion of a large organic cation such as guanidinium has been probed to stabilize the structure. In this work, we put forward the inclusion of imidazolium iodide (C₃N₂H₅I) as organic cation inside the CH₃NH₃PbI₃ matrix, as a reservoir to control the spontaneous loss of iodide. The introduction of imidazolium iodide in amounts below 20% has an impact on the crystallization process but not on the optical properties, positively controls non-radiative recombination and allows to improve the open circuit voltage of the solar cells. The present study paves way for a deep insight into the limit of multi-dimensional perovskite to further push the performance.