Regulation of Perovskite Nucleation and Orientated Crystal Growth via In Situ Self-Crosslinking Polymer for Bright Perovskite Light-Emitting Diodes

Hybrid halide perovskite films are becoming increasingly efficient in various applications, but several challenges still remain to be overcome. In this study, thermally polymerized additive N-vinyl-2-pyrrolidone (NVP) is utilized to tune the crystallization and orientation of mixed organo-metal perovskite films. Using in situ spectroscopy, it is demonstrated that NVP plays a crucial role in prolonging the crystallization process and separating the nucleation and crystal growth by forming an NVP-precursor intermediate phase. Additionally, the intermediate adduct effectively passivates defects, reduces nonradiative recombination, improves crystallinity, and enhances the transmission of charge carriers. NVP-containing perovskite light-emitting diodes (PeLEDs) are subsequently developed that exhibit stable and bright green luminance exceeding 240 000 cd m⁻². These findings provide valuable insights into manipulating the crystallization behavior of mixed organo-metal perovskite films.