The structural and optical properties of Yb3+/Er3+/Eu3+ co-doped LaVO4 nanoparticles have been investigated by XRD, FT-IR, HRSEM, DRS and fluorescence analysis. The crystal structure of all the synthesized samples showed the existence of tetragonal LaVO4. Influence of Eu3+ ions co-doping in Yb3+- Er3+: LaVO4 nanoparticles are systemically studied for both upconversion luminescence and emission studies. The energy transfer mechanism involved in LaVO4 phosphors is presented in detail based on their absorption, upconversion emission and pump power dependence study. The green to red fluorescence intensity ratio and asymmetry ratio are calculated with the variation of Eu3+ ion concentration. The upconversion fluorescence intensity ratio increases with the increase of pump power density which attributes the application of present phosphors as temperature sensors. Color purity of Yb3+/Er3+/Eu3+ co-doped LaVO4 nanophosphors hardly shows any change with variations in pump power. Dual mode luminescence of these nanophosphors finds its applications in anti-counterfeiting inks. © 2019