Synthesis and luminescence properties of a H2 annealed Mn-doped Y3Al5O12:Ce3+ single crystal for WLEDs
Abstract
A Czochralski grown Mn-doped Y3Al5O12:Ce3+ single crystal was thermally annealed in H2 atmosphere at different temperatures for 6 h and the corresponding absorption spectra, emission spectra, quantum yield (QY) and color-electric performance of Ce,Mn:YAG single crystal wafers were investigated before and after annealing. Moreover, the electron paramagnetic resonance (EPR) of doped Mn ions and a possible energy transfer process from Ce3+ to Mn2+ ions were discussed in detail. The corresponding results demonstrated that the H2 annealing process partly generated the intensity of luminescence spectra and improved the values of quantum yield and luminous efficacy (LE). H2 annealing at 1550 °C is the most optimal annealing conditions. After annealing, a maximum luminous efficacy reaching 119.93 lm W−1 and a color rendering index of 73.6 at a correlated color temperature of 5674 K were obtained, which demonstrates that the Ce,Mn:YAG single crystal is expected to be an optimal candidate for white LEDs.