High-Performance Perovskite Solar Cells Enabled by the Guanidine Derivative

The commercialization process of perovskite solar cells (PSCs) is hindered by their intrinsic defects and instability, which would trigger ion migration and efficiency degradation. Additive strategies have been widely investigated to enhance the performance of PSCs, while the limited solubility of some potential additives inhibits their further application. Herein, the guanidine derivative creatine is introduced into the perovskite precursor to decrease defects and minimize ion migration. Through theoretical and experimental measurements, we convince that the strong interaction between creatine and PbI₂ incites the solubility increase of creatine in DMSO. Specifically, the C=O in carboxyl and imine group could effectively chelate with Pb²⁺, while the amine group tends to form a hydrogen bond with iodide ions. Through synergistic effects, the addition of creatine can not only tailor the crystallization process to decrease defects but also obstruct ion migration. As a result, the PSCs achieve a champion power conversion efficiency of 25.51%, featuring an extremely enhanced stability, retaining over 93.2% of its initial value after exposure under an ambient environment for 1000 h. This work highlights the application potential of the additives with limited solubility in enhancing the performance of PSCs.