Fabrication of Al2O3– Ce:(Y, Tb)3 (Al, Mn)5O12 composite ceramic phosphors for high color rendering white LED/LD illumination

Ce: YAG- Al 2 O 3 composite ceramics are regarded as highly promising materials for laser illumination application due to their high luminous efficacy and thermal stability. Nevertheless, the Ce: YAG ceramics exhibit limited color rendering index (CRI) for indoor lighting due to their low red emission component. In this study, we synthesized high-performance Ce, Mn-doped (Y, Tb) 3 Al 5 O 12 –Al 2 O 3 composite ceramic phosphors via a vacuum solid-state sintering method. It was observed that the introduction of Mn 2+ ions created a second luminescence center with an emission peak centered at 580 nm. As the Mn 2+ concentration increased, the emission peak redshifted from 580 nm to 591 nm, leading to a significant enhancement in the color rendering index of the ceramics. The cross-energy transfer between Tb 3+ and Mn 2+ , Ce 3+ ions augmented the absorption and conversion of blue light by the ceramics, thereby reducing the correlated color temperature greatly. Based on these findings, ceramics with a Ce 3+ concentration of 3 at% and a Mn 2+ concentration of 4 at% exhibited the highest CRI values (81.3 and 75.6) under both laser excitation and LED excitation, establishing them as strong candidates for achieving high color rendering in white LED/LD illumination applications.