A broadband near-infrared emission Na3Al2(PO4)2F3:Cr3+ phosphor exhibiting zero photoluminescence quenching at 398 K

Abstract

Near-infrared (NIR) phosphors with emission peak wavelength longer than 800 nm have attracted significant attention due to their wide applications. However, a key challenge lies in developing high photoluminescence (PL) thermal stability phosphors. Herein, we synthesized a NIR phosphor Na₃Al₂(PO₄)₂F₃:Cr³⁺ (NAPOF:Cr³⁺) through the solid-state reaction method. The NAPOF:Cr³⁺ phosphor exhibits an intense broadband emission peak at 810 nm and covers a wide spectral range from 650 to 1100 nm. Notably, this phosphor demonstrates zero PL thermal quenching even at 398 K. This outstanding thermal stability can be primarily ascribed to the inherent structural rigidity and wide bandgap of the NAPOF crystal together with the medium electron–photon coupling effect. The fabricated broadband NIR light-emitting diodes (LEDs) using the NAPOF:Cr³⁺ phosphor exhibits a highest NIR light output power of 28.1 mW under a drive current of 150 mA, and a corresponding electro-optical conversion efficiency of 8.6%. Our findings highlight the tremendous potential of the NAPOF:Cr³⁺ phosphor for broad-spectrum NIR-LED applications.