Enhanced up-conversion photoluminescence and dielectric properties of Er- and Zr-codoped strontium bismuth niobate ceramics

Er- and Zr-codoped strontium bismuth niobate ceramics, Sr 0.97 Er 0.03 Bi 2 Nb 2− x Zr x O 9 (SBN x ) with different x (0≤ x ≤0.1), were synthesized by the solid state reaction method. Their structural, up-conversion (UC) photoluminescence , and dielectric properties were investigated. By Rietveld structural refinement, all SBN x samples exhibited a polycrystalline bismuth-layered perovskite structure with space group A2 1 am. With deliberate introduction of Zr 4+ ions in the bismuth-layered perovskite structure, SBN x samples presented simultaneously enhanced UC photoluminescence and dielectric properties. The UC photoluminescence was investigated as a function of Zr 4+ concentration and incident pump power. Under the 980   nm near infrared (NIR) excitation, bright UC green and weak red emissions were observed which corresponded to the transitions from 2 H 11/2 / 4 S 3/2 and 4 F 9/2 to 4 I 15/2 level, respectively. With x increase, the UC luminescence improvement of SBN x can be attributed to the local distortion of crystal field surrounding the Er 3+ activator which induced by different ionic radii of Zr 4+ and Nb 5+ ions. The dependence of UC emission intensity on pumping power showed that two photon energy transfer process was involved in the UC green and red emissions. Furthermore, electrical measurements indicated that the introduction of Zr 4+ distinctly increased the ferroelectric to paraelectric phase transition temperature ( T C ) of SBN x ceramics from 724   K to 762   K as x ranging from 0.0 to 0.1. It is believed that B site doping in SBN x by large Zr 4+ ion is an effective method to improve UC luminescence and electrical properties of this potentially multifunctional optical-electro material.