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.