Eu 3+ and Tb 3+ ions were site-selectively doped into LaLuO 3 with the orthorhombic perovskite-type structure (ABO 3 ), and their luminescence properties were examined considering the doping sites (A or B sites). The X-ray diffraction analysis revealed the expansion or contraction of the unit cell volumes of the materials depending on the doping sites. The spectra of X-ray absorption near edge structure for the Eu and Tb L III edge exhibited different shapes for the ions at A and B sites, confirming the site-selective doping of Eu 3+ and Tb 3+ in LaLuO 3 . The photoluminescence (PL) and PL excitation (PLE) spectra of the materials also showed some differences caused by the doping sites. The intensities of the Eu 3+ PL peaks derived from the 5 D 0 − 7 F 1 transitions and those from the 5 D 0 − 7 F 2 transitions were markedly different between Eu 3+ at A sites and those at B sites because of the different site symmetries. The splitting of the intense Tb 3+ PL peaks originating from the 5 D 4 − 7 F 5 transitions and the absence of PL peaks from 5 D 3 − 7 F J transitions were found only for Tb 3+ at B sites because of the strong crystal field at B sites. In addition to the PL spectra, the positions of PLE peaks originating from charge transfer transitions in Eu 3+ and the 4f−5d transitions in Tb 3+ depended on the doping sites. The successful site-selective doping enabled us to clarify the site-sensitive luminescence properties of Eu 3+ and Tb 3+ doped in the perovskite-type LaLuO 3 .

Highlights 1. Phase-pure Eu 3+ doped Ca2LaTaO6 (CLTO) and Ba2LaTaO6 (BLTO) were prepared. 2. Eu 3+ were confirmed to be at A sites in CLTO and B sites in BLTO by XANES analysis. 3. Eu 3+ site-dependent PL spectra were obtained using the Eu 3+-site-confirmed samples. 4. Site-dependent PL and the lifetime were examined systematically by CT excitation. 5. High external efficiency of 28% was found in the Eu 3+ doped BLTO double perovskite.