Modulation of emission behavior of (Y, Gd)AG by Ce3+ doping

The use of InGaN/GaN blue light chips to excite surface-coated yellow phosphors is one of the common strategies for the preparation of WLEDs. In this study, a series (Y,Gd) 3 Al 5 O 12 ((Y,Gd)AG) phosphors doped with different concentrations of Ce 3+ were prepared using the co-precipitation method. The yellow light emission intensity of the phosphor reaches its maximum at a Ce 3+ concentration of 5 %. This observation is consistent with theoretically quenching concentration (4.7 %) calculated by the Stern - Volmer formula and the optimal quantum yield (69.18 %). Further research indicates that the emission efficiency of the sample remains almost same after 7 days and maintained room temperature efficiency of 67 % at 400 K, with a color temperature value of 2662 K and a CRI value superior to that of YAG:Ce. The results TR-PL tests showed that when the concentration of Ce 3+ doping was gradually increased up 5 %, the distance between the emission centers becomes shorter, which leads to a decrease in the emission lifetime and thereby improves the luminous efficiency. When the concentration exceeds 5 %, concentration quenching leads to an increase in non-radiative processes, and this quenching mechanism is identified as energy transfer between Ce 3+ - Ce 3+ ions. This result provides ideas for obtaining highly efficient yellow phosphors, and also provides a realization path for improving the performance of CCTs and CRIs in WLEDs.