Enhanced Photoluminescence of Gd 3 Al 4 GaO 12 : Cr 3+ by Energy Transfers from Co-Doped Dy 3 .

LEDs for plant lighting have attracted wide attention and phosphors with good stability and deep-red emission are urgently needed. Novel Cr 3+ and Dy 3+ co-doped Gd 3 Al 4 GaO 12 garnet (GAGG) phosphors were successfully prepared through a conventional solid-state reaction. Using blue LEDs, a broadband deep-red emission at 650-850 nm was obtained due to the Cr 3+ 4 T 2 → 4 A 2 transition. When the Cr 3+ concentration was fixed to 0.1 mol, the crystal structure did not change with an increase in the Dy 3+ doping concentration. The luminous intensity of the optimized GAGG:0.1Cr 3+ , 0.01Dy 3+ was 1.4 times that of the single-doped GAGG:0.1Cr 3+ . Due to the energy transfer from Dy 3+ to Cr 3+ , the internal quantum efficiency reached 86.7%. The energy transfer from Dy 3+ to Cr 3+ can be demonstrated through luminescence spectra and fluorescence decay. The excellent properties of the synthesized phosphor indicate promising applications in the agricultural industry.