Efficient and thermally stable broadband near-infrared emission in a garnet Gd3In2Ga3O12:Cr3+ phosphor

Abstract

Compact broadband near-infrared (NIR) light sources generated by phosphor-converted light-emitting diodes (pc-LEDs) have attracted considerable interest in emerging smart NIR spectroscopy applications. However, discovering a highly efficient and thermally stable broadband NIR phosphor still remains a significant challenge. Here, we report a new efficient garnet phosphor, Gd₃In₂Ga₃O₁₂:Cr³⁺, which has a broadband emission peaking at 780 nm with a full-width at half maximum (FWHM) of 124 nm. The optimized Cr³⁺-doping concentration of this material is particularly high (9 mol%), resulting in a high quantum yield and absorption efficiency of 85.3% and 49.1%, respectively. Moreover, 87.7% of the initial emission intensity can be retained when heating up to 150 °C, demonstrating the excellent thermal stability of this material. Fabricating a prototype NIR device by using the as-prepared material in combination with a blue LED chip, an excellent NIR output power (33.7 mW) with a NIR photoelectronic conversion efficiency of 12.0% can be achieved under a 100 mA driving current. These results indicate that the Gd₃In₂Ga₃O₁₂:Cr³⁺ phosphor may have great potential for broadband NIR pc-LED applications.