Photoluminescence of cerium-doped (Ca1−xSrx)3RE2Ge3O12 garnet phosphors for solid state lighting: Relating structure to emission

A novel family of cerium-doped garnet oxide phosphors, (Ca1−xSrx)3RE2Ge3O12:Ce,Li (2%, 2%) (x = 0–1, RE = Y, Lu), was prepared using a conventional high-temperature ceramic route and was found to exhibit green luminescence under blue excitation. These compounds were characterised by synchrotron X-ray diffraction and photoluminescence spectroscopy. The results from this study were compared with other known Ce-doped garnets, including yttrium aluminium garnet, leading to a deeper understanding of the relationship between crystal structure and emission wavelength. In particular, the relationship between Ce3+ emission and the distortion factor of the dodecahedral doping site (d88/d81) was examined.