Abstract
Spectral coverage and saturability within 700-1100 nm of phosphor-converted near infrared light-emitting-diodes (pc-NIR LEDs) are crucial for the practical applications in bioimaging, food quality analysis and night vision fields, while developing ultra-broadband NIR phosphors are still a challenge. Herein, we reported a broadband NIR phosphor LiInP2O7: Cr3+ in phosphate system. The emission spectrum of this phosphor covers 700-1200 nm with a full width at half maximum (FWHM) of 165 nm and an emission peak centering at 860 nm under 460 nm excitation. This broadband emission is verified to be derived from T-4(2) (g) -> (4)A(2) (g) transition of Cr3+ in a single crystal site. To further expand the emission spectrum, Cr3+ -> Yb3+ energy transfer in LiInP2O7 was designed, and an ultra-broadband emission with a FWHM of 225 nm was obtained through appropriate amount of Yb3+ codoping. The energy transfer efficiency can reach as high as 81% in this material. Furthermore, the energy transfer mechanism, quantum yield, thermal stability and fabrication performance were investigated in detail, demonstrating the ability of achieving ultra-broadband and efficient NIR emission of LiInP2O7: Cr3+, Yb3+ phosphor material. (C) 2021 Elsevier B.V. All rights reserved.
NSTL
Elsevier