Synthesis of Er³⁺ doped KNbO₃ nanocrystals and nanoceramics with outstanding up-conversion luminescence behaviors

Abstract

Rare earth doped perovskite has become one of the most attractive multifunctional materials benefiting from the unique ferro-/piezoelectric, photocatalytic and photoluminescence properties. In this contribution, a series of Er3+ doped KNbO3 nanocrystals with distinctive morphologies, i.e., nanocubes, nanocuboids, and quasi-nanospheres, were prepared via a facile molten salt synthesis method. Furthermore, using the as-synthesized nanocrystals, the Er3+ doped KNbO3 ceramics with homogeneous nanograins were obtained. The growth mechanism of the nanocrystals with different morphologies and sintering process of the nanoceramics were rationally proposed, respectively. It was demonstrated that the morphology of the nanocrystals could be controlled by adjusting the doping amount of Er3+ and the structure of the as-sintered nanoceramics strongly depends on the morphology of the pristine nanocrystals. Impressively, the Er3+-KNbO3 nanocrystals and nanoceramics exhibited excellent up-conversion photoluminescence (UC PL) properties. This work may pave a new way to the structure-controlled synthesis of rare earth doped perovskite oxides and related nanoceramics, which show large potential in applications of novel multifunctional devices.