A High-Efficiency NIR-II Emitting LiAlSiO4:Cr/Ni Phosphors through Violet Excitation for NIR pc-LED Application

Near-infared phosphor-converted light-emitting diodes (NIR pc-LEDs) are next-generation NIR light sources due to their long life, low cost, and compactness. Unfortunately, there is a lack of efficient NIR-II phosphors with high efficiency and large full width at half-maximum (fwhm) that can be excited by violet LED. Here, a series of Cr3+/Ni2+-codoped LiAlSiO4 with unprecedented emission peaking at 1150 nm (∼1000–1400 nm, fwmh ∼191 nm) were synthesized via a solid-state reaction. More importantly, the phosphors exhibit high efficiency and excellent thermal stability under violet emission excitation. Moreover, the NIR pc-LED devices as a NIR-II light source have been fabricated through a combination violet LED and optimized LiAlSiO4:Cr3+/Ni2+ phosphors, which are well applied to high-penetration imaging and nondestructive fruit damage inspection. These results indicate that the LiAlSiO4:Cr3+/Ni2+ phosphors have great potential applications as NIR light sources.