LaMgGa_(11)O_(19):Cr~(3+),Ni~(2+) as Blue-Light Excitable Near-Infrared Luminescent Materials with Ultra-Wide Emission and High External Quantum Efficiency

摘要

Highly efficient luminescence material covering near-infrared (NIR) Ⅰ(700–1000 nm) and Ⅱ (1000–1700 nm) is of great importance for phosphorconvertedNIR light-emitting diodes (pc-LEDs) light sources. The lack ofultra-wide emission NIR luminescent materials that can be excited bycheap blue-LEDs, suspends the applications of NIR pc-LEDs. Ni~(2+)-activatedphosphor usually gives an NIR-Ⅱ region emission, however, it presentslow quantum efficiency due to poor absorption in blue light region. Here,a blue-LED-excitable (400–480 nm) LaMgGa11O19(LMG):Cr~(3+),Ni~(2+) NIRemittingphosphor is reported. Significantly, by constructing energy transferfrom Cr~(3+) to Ni~(2+), it demonstrates an ultra-wide NIR emission from 650 to1600 nm, and greatly improves external quantum efficiency (EQE) from 2%to 53%. Besides, the weakened exchange coupling of Ni~(2+)?Ni~(2+) pairs leadsto an abnormal blue-shift of Ni~(2+) emission with increasing temperature.The fabricated NIR pc-LED gives a high output power of 8 mW at 20 mAwith the photoelectric efficiency of 14%, which favors potential applicationsin night-vision technology, medical applications, non-destructive analysis,and spectroscopic analysis. This exploration of Cr~(3+)-Ni~(2+) co-doped strategyfor realizing high-performance NIR-emitting phosphor provides novel andeffective design insights into developing more ultra-broadband NIR pc-LEDsbased on cheap blue LEDs.