Selective enrichment strategy induces ultra-broadband NIR emission in Cr3+-doped multi-phase glass-ceramics for NIR spectroscopy applications

Abstract

Near-infrared (NIR) spectroscopy has gained widespread application in food analysis, disease diagnosis, fingerprint analysis, and security monitoring. However, the lack of efficient, broadband NIR luminescent materials hinders the full potential of this technology. Here, an ultra-broadband and high-efficiency Cr3+-doped multi-phase glass-ceramics containing MgAl2O4, Al2SiO5, and SiO2 nanocrystals was discovered, which exhibited an ultra-broadband NIR emission (λem ∼ 900 nm) with a full width at half maximum more than 300 nm and a high internal quantum yield of 50.9% under the excitation of 465 nm blue light. Moreover, the integrated emission intensity at 100 °C and 150 °C can keep 88% and 77% of that at room temperature. The ultra-broadband, high efficiency, and thermally robust luminescence of this Cr3+-doped multi-phase glass-ceramics can be attributed to the selective enrichment of Cr3+ ions into different nanocrystals with octahedral sites, and medium electron-photon coupling effect. The NIR glass-ceramics-converted light-emitting diode constructed by the glass-ceramics combined with 465 blue LED chip produced an excellent NIR output and photoelectric conversion efficiency of 274 mW/1007 mW and 3.43%/2.79% at 100 mA/320 mA drive current, which demonstrated superior overall performance to the NIR device built by using the well-known NIR phosphors. Additionally, the NIR camera can capture the image of license plate and nectarine, as well as identify the residual drug content in the bottle under the irradiation of the NIR device constructed by the glass-ceramics. This work not only presented an ultra-broadband and high-efficiency NIR material but also highlights a design strategy to effectively enhance the efficiency and broadband characteristics of NIR glass-ceramics.