Structural induced tunable NIR luminescence of (Y,Lu)3(Mg,Al)2(Al,Si)3O12: Cr3+ phosphors

Garnet-type (Y,Lu)3(Mg,Al)2(Al,Si)3O12: Cr3+ compounds were successfully synthesized by high-temperature solid-phase reaction method. Starting from Y3Al5O12, Mg2+-Si4+ pairs were used to replace Al(1)3+-Al(2)3+ in octahedral and tetrahedral site, respectively, and then Y3+ was substituted by Lu3+ in dodecahedra of Y3(MgAl)(Al2Si)O12: Cr3+. Narrow-band to broad-band tunable NIR luminescence was achieved by ionic substitution at different polyhedral positions. The peak emission wavelength can be tuned from 705 to 770 nm, and the full width at half maximum (FWHM) can be extended from 27 to 160 nm. The results indicate that Y3(MgAl)(Al2Si)O12: 0.06Cr3+ is a promising NIR material. Under the excitation of blue light, the peak wavelength of Y3(MgAl)(Al2Si)O12: 0.06Cr3+ is about 760 nm with a FWHM of ∼160 nm and an IQE of 64%. Furthermore, the luminescence intensity at 150 °C remains at 84.2% of that at room temperature. Additionally, packaging performance was studied to evaluate its practical application in LEDs.