Luminescence properties and energy transfer of broadband NIR phosphor Li2MgZrO4: 1.0%Cr3+, y%Yb3

Abstract

The discovery of high thermal stability, broad-band near-infrared (NIR) fluorescent phosphors holds significant potential in applications such as non-destructive testing, promoting plant growth, and night vision devices. In this study, a novel broad-band NIR phosphors Li₂MgZrO₄ (LMZ): 1.0 %Cr³⁺, y%Yb³⁺ were synthesized via a high-temperature solid-state reaction method, with the optimal doping concentration found to be y = 1.5. These phosphors exhibited broad NIR emission in the range of 700-1050 nm by effective energy transfer from Cr³⁺ to Yb³⁺. The maximum full width at half maximum (FWHM) of the Cr³⁺/Yb³⁺ co-doped LMZ phosphor is 270 nm. The thermal stability of the phosphors was improved with Yb³⁺ co-doping. Additionally, energy transfer from Cr³⁺ to Yb³⁺ was confirmed through luminescence spectra and lifetime analysis. Finally, NIR pc-LED devices composed of a 460 nm ultraviolet chip and LMZ: 1.0 %Cr³⁺, 1.5 %Yb³⁺ phosphors were fabricated, offering a highly promising source of invisible light. These results demonstrate the wide-ranging potential applications of this novel, high thermal stability, and ultra-broad NIR emitting fluorescent phosphor.

Keywords: High Thermal Stability; NIR; Ultra-wideband.