Integrated “all-in-one” strategy toward boosting photoluminescence performance in Cr3+- activated ganet phosphors

Boosting photoluminescence quantum efficiency (QE) while maintaining thermal stability is among the primary challenges in the commercialization of near-infrared (NIR) phosphor-converted light-emitting diodes (pc-LEDs). In this work, by chemical unit co-substitution of [Al³⁺-In³⁺] for [Ga³⁺-Ga³⁺], adding fluxes, and sintering in CO atmosphere, Cr³⁺ activated Gd₃In_yAl_xGa_5-x-yO₁₂ phosphors exhibit emission from 650 to 1100 nm under excitation of 450 nm. At 423 K, the integrated photoluminescence intensity remains 96.7% of that at room temperature for Gd₃In_1.5Al_0.5Ga₃O₁₂: 0.015Cr³⁺. Significantly, the corresponding internal quantum efficiency (IQE) has been improved from 76.5% to 90.5%. X-ray photoelectron spectroscopy (XPS) and UV–Vis–NIR absorption spectra reveal that only Cr³⁺ is present in the phosphor. The obtained phosphor is fabricated into LEDs and demonstrated their application in biological imaging. The proposed all-in-one strategy provides guidance for design of high-performance NIR phosphors.