We report the synthesis of Tb(1−x)PO 4 :xEu 3+ (x=0–1) nanophosphors directly by a simple hydrothermal method with citric acid (CA) as the organic additive and without further sintering treatment. The nanocrystals are well-faceted and show a highly symmetrical structure. The energy transfer between Tb 3+ and Eu 3+ in TbPO 4 nanocrystal was investigated, and tunable emission wavelengths were realized in the materials by changing the doping concentration of Eu 3+ . The increase of Eu 3+ concentration can lead to the interaction between neighboring Eu 3+ , which results in concentration quenching.