Achieving high quantum efficiency broadband NIR Mg 4 Ta 2 O 9 :Cr 3+ phosphor through lithium ion compensation.

Ultra-efficient broadband near-infrared (NIR) phosphor-converted light-emitting diodes (pc-LEDs) are urgently needed to improve the detection sensitivity and spatial resolution of current smart NIR spectroscopy-based techniques. Nonetheless, the performance of NIR pc-LED have severely limited owing to the external quantum efficiency (EQE) bottleneck of NIR light-emitting materials. Herein, we advantageously modified a blue LED excitable Cr 3+ -doped tetramagnesium ditalate (Mg 4 Ta 2 O 9 , MT) phosphor through lithium ion as a key efficient broadband NIR emitter to achieve high optical output power of NIR light source. The emission spectrum encompasses the 700-1300 nm electromagnetic spectrum of first biological window (λ max = 842 nm) with a full-width at half-maximum (FWHM) of ∼2280 cm -1 (∼167 nm), and achieves a record EQE of 61.25% detected at 450 nm excitation through Li-ion compensation. A prototype NIR pc-LED was fabricated with MT:Cr 3+ , Li + to evaluate its potential practical application, which revealed a NIR output power of 53.22 mW at a driving current of 100 mA, and a photoelectric conversion efficiency of 25.09% at 10 mA. This work provides an ultra-efficient broadband NIR luminescent material, which shows great promise in practical applications and presents a novel option for the next generation of high-power compact NIR light sources. This article is protected by copyright. All rights reserved.