Bridging between structure and optimum luminescence for nearly monodispersed Ce1−xGdxF3:Eu3+ nanoparticles

► We reported a systematic study on bridging between structure and optimum luminescence for Ce1−xGdxF3:Eu3+ nanoparticles. ► With increasing Gd3+ content, lattice symmetry surrounding Eu3+ was highly distorted. ► By structural modification, the color purity was significantly improved. ► The highest quantum efficiency was optimized to be 59.7%.