RbCl doping enhances pure-blue emission in mixed-halide perovskite quantum dot glass through crystallization promotion and defect passivation

All-inorganic lead halide perovskite (CsPbX 3 , X = Cl, Br, or I) quantum dots (QDs) glasses have attracted considerable attention due to their excellent stability. However, realizing pure-blue emission CsPbX 3 (X = Br, Cl) QDs glasses with high photoluminescence quantum yield (PLQY) remains a challenge. This study employs RbCl as a dual-functional dopant to regulate the photoluminescence (PL) wavelength and promote the crystallization of CsPbBr 2 Cl 1 QDs embedded in a glass matrix. During thermal treatment, Cl − ions separated from the glass network enhance CsPbBr 2 Cl 1 QD crystallization by increasing the internal Cl/Br ratio and passivating Cl vacancy defects. Simultaneously, high-field-strength Rb + ions partially enter Cs + sites, further promoting crystallization and suppressing Cl vacancies. The synergistic effect of Cl − and Rb + ions induces PL wavelength from 495 nm to 473 nm, while the PLQY increases from 17% to 25%. Among the RbCl-doped samples, the LED based on 4.5 mol% RbCl exhibits the widest color gamut, covering 79.7% of the Rec. 2020 standard. This study introduces a bifunctional dopant strategy to fabricate high-performance, pure-blue-emitting CsPbBr x Cl 3-x QDs glasses. The developed material shows great potential for advanced applications in LED lighting, backlight displays, information storage, and optical anti-counterfeiting.