Interfacial mechanisms of enhanced photoluminescence in AgI-doped red light emitting perovskite quantum dot glass

Red light emitting perovskite quantum dot (PQD) glass, with narrow-band emission and excellent stability, holds great potential for applications in liquid crystal displays. However, its low photoluminescence quantum yield (PLQY) remains the biggest obstacle limiting its practical application. Additionally, the mechanism behind the enhancement of the PLQY is not well understood, which restricts the further improvement of the PLQY in red light emitting PQD glass. In this work, AgI doped red light emitting CsPbBrI 2 PQDs glass exhibitated significantly improved PLQY. The underlying mechanisms shown that the formation of Ag nanoparticles (NPs) promotes a localized surface plasmon resonance (LSPR) effect, which increases the charge carrier density and optical activity. Density functional theory (DFT) calculations indicate a widening of the PQD bandgap upon AgI doping, which contributes to reduced non-radiative recombination and improved PLQY. Attractively, the optimal doping concentration of 0.4 mol% AgI resulted in a maximum PLQY of 62.4 %. Finally, the PG0.4 sample demonstrated excellent thermal, water, and photostability, maintaining over 88 % of its initial emission intensity under prolonged stress conditions. These results highlight the potential of AgI-doped red light emitting CsPbBrI 2 PQDs for use in high-performance optoelectronic devices, offering both enhanced luminescence and long-term stability.