Cs/FA Gradient Distribution in Perovskite NCs Enables Sub-Nanometer Spectral Regulation and BT.2020 Pure-Green Electroluminescence

Abstract

Lead halide perovskite exhibits great prospects in next-generation display. However, single-cation inorganic perovskite nanocrystals (NCs) still suffer from offset gamut coordinates determined by bandgap, short operating life, and low-efficiency in light-emitting diodes (LEDs), on account of the limitations in lattice stability and defect levels. Here, a thermodynamic co-competition strategy is proposed for fabricating Cs_1−xFA_xPbBr₃ NCs, which reveals the spatial distribution of A-site cations and the improvement of photoelectronic performance. This strategy achieves precise control of NCs in the pure-green range with an accuracy of sub-nanometer, further promotes the comprehensively filling-suppressing effect of incongruous lattice and surface defects. Finally, the high-precision adjusting in electroluminescence is achieved, and the champion device achieves a CIE coordinate of (0.121, 0.788), meeting the pure-green range in BT.2020. Simultaneously, the PeLED demonstrates an EQE exceeding 20% with superior stability, accompanied by 20-fold improvement in lifetime, indicating tremendous potential in next-generation display.