Probing Local Structural Changes by Sharp Luminescent Infrared Nanophosphor for Application in Light-Emitting Diodes

Cr3+-doped infrared phosphors are promising candidates for next-generation phosphor-converted infrared light-emitting diodes (LEDs) because they can, in principle, tune and convert the luminescence spectra from an LED chip. However, most studies focus on broad-band Cr3+-doped phosphors, and the control mechanism of Cr3+-doped phosphors with sharp line emissions remains ambiguous. Here, we report LiGa5(1–x)Al5xO8:Cr3+ phosphors with sharp line emissions. The luminescence analysis reveals the subtle change of the local structure around Cr3+, which cannot be well resolved by X-ray diffraction. The deviation between the temperature-dependent photoluminescence and decay profile is introduced as well. Furthermore, the morphologies of LiGa5(1–x)Al5xO8:Cr3+ phosphors with high aluminum concentration demonstrate their great potential for mini-LED applications. Finally, an LED package is constructed, and it reveals the potential for angiographic applications. This study opens up a new understanding and perspective for Cr3+-doped sharp emission phosphors and reveals their potential for LED applications.