The pure and Er3+-modified binary Pb(Zn1/3Nb2/3)O3–9PbTiO3 (PZN–9PT) single crystals were grown by using the flux method. The phase structure of the as-grown single crystals at room temperature was confirmed by the x-ray diffraction analysis. The effect of Er3+ addition on the electrical properties and upconversion luminescence of PZN–9PT was investigated. The rhombohedral to tetragonal phase transition temperature and the Curie temperature of the Er3+-modified PZN–9PT single crystals were 370 and 451 K, respectively. The coercive field E C at room temperature was evidently higher by 11.6 kV/cm than that of the PZN–9PT single crystals (E C, ∼3.5 kV/cm). Furthermore, the green and red upconversion emission bands were obtained under the 980 nm excitation, which are related to (2H11/2, 4S3/2) → 4I15/2 and 4F9/2 → 4I15/2 transitions.
