In3+ co-doped YVO4:5% Eu3+ red phosphors were synthesized via a facile hydrothermal method. The impacts of In3+ co-doping concentration onto the crystal structure, morphology, and photoluminescence properties were elucidated by using X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence spectra, and the luminescence intensity change. The results indicated that with increasing the In3+ co-doping concentration, the intensity of excitation and emission spectra was continuously increased, reached maximum at In3+ concentration of 5 mol%, and then was diminished for higher In3+ content which indicated concentration quenching. The distinct enhancement of the photoluminescence of YVO4: Eu3+, In3+ phosphors at lower In3+ co-doping concentration can be attributed to the incorporation of In3+ improving the host lattice absorption of YVO4. Thereafter, with the increase of In3+ concentration exceeding 5 mol%, the emission intensity was decreased which is mainly due to the fact that the electronegativity of indium is greater than yttrium, and it is not beneficial to the charge transfer process of O-2 -> V5+ inside the VO43+ ions, thus further weakening the energy transfer from VO43+ groups to Eu3+ ions. (C) 2016 The Society of Powder Technology Japan. Published by Elsevier B. V. and The Society of Powder Technology Japan. All rights reserved.