A High-Crystallinity Transparent Glass-Ceramic Enables Encapsulant-Free, High Quantum Efficiency NIR-II Miniature Light Source

P Zhang and XY Liu and Y Ji and B Zhou and WC Wang and QY Zhang, ADVANCED FUNCTIONAL MATERIALS (2025).

DOI: 10.1002/adfm.202530116

The second near-infrared (NIR-II) light source is of considerable importance for broad frontier applications in biomedical imaging, non- destructive testing, and night vision. However, the conventional phosphor-converted light-emitting diodes (pc-LEDs) require polymer encapsulants, which impose a fundamental limitation on NIR-II light sources owing to severe reabsorption and restricting output power. To overcome this challenge, a monolithic MgGa2O4:Cr3+/Ni2+ glass-ceramic is demonstrated that serves as a highly transparent, encapsulant-free converter. Through precise microstructural control to suppress preferential crystal orientation, the glass-ceramic achieves approximate to 90% transmittance together with efficient Cr3+ to Ni2+ energy transfer. The resulting glass-ceramic converted LED (GCc-LED) delivers intense broadband emission across NIR-II regions with an ultra-high external quantum efficiency of 49.4%, and a high NIR output power of 114.1 mW (at 320 mA) is obtained. It also shows excellent thermal stability with a high activation energy of 0.39 eV. The superior performance of the GCc-LED in high-contrast bioimaging, night vision, and non-destructive sensing is further demonstrated. This work establishes an effective way to overcome the material constraint of traditional pc-LEDs and shows great promise for the development of high- power, miniature NIR-II light sources.

Return to Publications page