Cation vacancy-boosted BaZnB4O8:xEu3+ phosphors with high quantum yield and thermal stability for pc-WLEDs

Abstract

Achieving high luminescent quantum yield and thermal stability of phosphors simultaneously remains challenging, yet it is critical for facilitating high-power white light emitting diodes (WLEDs). Herein, we report the design and preparation of the layered structure BaZnB₄O₈:xEu³⁺ (0.10 ≤ x ≤ 0.60) red phosphors with high quantum yield (QY = 76.5%) and thermal stability (82.8%@150 °C) by the traditional solid-state reaction method. The results of XRD and Rietveld refinement show that the presence of Eu³⁺ ions at Ba²⁺ sites causes the formation of cation (Zn²⁺/Ba²⁺) vacancies in the lattice. The PL and PL decay results reveal that the quenching concentration of BZBO:xEu³⁺ phosphors is as high as 50%, and the lifetime remains unchanged with Eu³⁺ concentration due to the unique structure of the host and the cation vacancies generated by the heterovalent substitution. Furthermore, on a 395 nm near-UV chip, a pc-WLED device with exceptional optical performance (CCT = 4415 K, CRI = 92.1) was realized using the prepared BZBO:0.50Eu³⁺ as a red phosphor. Simple synthesis and excellent performance parameters suggest that the reported BaZnB₄O₈:xEu³⁺ phosphors have promising applications in high-power pc-WLEDs. At the same time, it also indicates that cationic vacancy engineering based on heterovalent ion substitution is a potential strategy for improving luminescence quantum yield and thermal quenching performance.