Six-and five-coordinated Cr^(3+)in Ga_(2)GeO_(5) invokes tunable broadband near-infrared emission toward night-vision applications

Broadband near-infrared(NIR)light sources play a critical role in widespread applications such as advanced spectroscopy analysis and nondestructive testing.One of the most promising techniques is the fabrication of broadband NIR phosphor-converted light emitting diode(pc-LED).However,the purposeful design of a tunable ultra-broadband NIR-emitting phosphor in a single host is still a challenge.In this work,Ga_(2)GeO_(5) with two sites of six-coordinated[Ga1O_(6)]and five-coordinated[Ga2O_(5)]is chosen to host Cr^(3+),successfully producing tunable broadband NIR luminescence(680-1350 nm).It can be tuned largely from 828 to 970 nm with the full-width at half maximum(FWHM)varied from 208 to 258 nm just by simply adjusting the Cr^(3+)-doping content.The tailoring of the Cr^(3+)NIR spectral emission is ascertained to the site occupation preference and competition.The encapsulation of a prototype of NIR pc-LED with an output power of 29.5mW@390 mA is conducted for the implementation of night-vision application.This work provides a novel broadband NIR phosphor by Cr^(3+)-doping in both the sixand five-coordination field,meanwhile,further demonstrating the feasibility of discovering new host material with more than one crystallographic site for Cr^(3+)to trigger tunable broadband NIR emission.