Overall Performance Improvement of Perovskite Green LEDs by CsPbBr₃&Cs₄PbBr₆ Nanocrystals and Molecular Doping.

Abstract

Metal halide perovskites hold great promise for display technologies owing to their excellent optoelectronic properties. Recent advances in perovskite light-emitting diodes (PeLEDs) have improved their efficiency, brightness, and operational stability, but simultaneously boosting these metrics remains challenging. Additionally, other critical metrics such as power consumption, color purity, and gamut have received little attention. Here, a co-additive approach is proposed to regulate the perovskite crystallization, enabling the synthesis of CsPbBr₃&Cs₄PbBr₆ dual-phase nanocrystals (NCs) and the formation of nanoscale concave-convex morphology, as well as to change its semiconductor polarity by molecular doping. Due to the reduced defect density, balanced charge injection, and improved light extraction efficiency, the PeLEDs achieve a remarkable external quantum efficiency (EQE) of 28.2%, a high brightness of over 150000 cd m^-2 and a T₅₀ lifetime of 4291 h, along with an ultra-narrow spectral linewidth (16.5 nm), an ultra-low driving voltage (1.9 V), and a superior Rec. 2020 color gamut coverage (CGC) of 92%.