Efficient near-infrared luminescence in LiInO2:Cr3+ phosphor for light-emitting-diodes

Abstract

Broadband near-infrared (NIR) spectroscopy produced by efficient and miniaturized NIR phosphor-converted light-emitting diodes (pc-LEDs) has been utilized in portable and mobile devices to realize a variety of applications such as bio-imaging, food-quality analysis, and night-vision. However, developing blue-light excitable NIR phosphor material with efficient emission around 900 nm remains a great challenge. Herein, an efficient LiInO2:Cr3+ phosphors with an emission peak of 897 nm and a full width at half maximum (FWHM) of 129 nm excited by 468 nm were successfully synthesized under a protective atmosphere. The optimized sample shows a particularly high absorption efficiency (AE = 57.8%) and an excellent internal quantum efficiency (IQE = 42.4%), resulting in a relatively high external quantum efficiency (EQE = 24.5%) compared to the developed phosphors with emission peak around 900 nm. Disappointingly, the emission intensity at 373 K of this material retains only 29.6% of that at room temperature, and the strong electron-phonon-coupling (EPC) effect should be responsible for the relatively poor thermal stability. Thus, this work demonstrated an attempt to develop efficient broadband NIR phosphors for spectroscopy applications, and also performed a comprehensive investigation to understand this material.