Multi-site occupancy high-efficient Mg2LaTaO6:Cr3+ phosphor for application in broadband NIR pc-LEDs

Abstract

As a new generation of near-infrared (NIR) light source, phosphor-converted NIR light emitting diodes (NIR pc-LEDs) have broad application prospects in biological tissue imaging, night vision and chemical composition analysis. However, most NIR emitting phosphors are still limited to short-wavelength, narrow-band emission and low efficiency. Here, based on the multi-site occupation strategy, the NIR phosphor Mg2LaTaO6:Cr3+ (MLT:Cr3+) achieves an efficient broadband NIR emission with the full width at half maximum (FWHM) of 203 nm in the range of 600–1300 nm under the excitation of 468 nm blue light. The phosphor MLT:0.01Cr3+ not only exhibits an excellent internal quantum efficiency (IQE) of 85.6 %, but also has good thermal stability and remains about 64.2 % photoluminescence (PL) intensity of room temperature at 423 K. Furthermore, the MLT:0.01Cr3+ phosphor was combined with a blue LED chip to fabricate the NIR pc-LED device, and its potential applications were successfully realized in information encryption, bioimaging and the qualitative or quantitative analysis of mixture of ethanol and water.