Controllable synthesis and luminescence properties of monodisperse lutetium oxide spheres with tunable particle sizes and multicolor emissions

Abstract

A variety of uniform and well-dispersed Lu2O3 spheres with tunable particle sizes have been synthesized by a two-step process. The spherical Lu(OH)CO3 precursor was firstly obtained through a homogeneous precipitation route. Subsequently, the Lu2O3 spheres were obtained during an annealing process. The particle sizes of Lu(OH)CO3 precursors can be adjusted in a controlled manner by simply tuning the amount of reaction temperature and time or component of solvent. The average particle sizes of the precursor spheres decrease gradually by increasing the amount of isopropanol solvent. After a calcination process, the Lu2O3 products perfectly preserve the spherical shape, unifomity, and good dispersity of the precursors except for a shrinkage in particle size, resulting in the formation of a series of Lu2O3 spheres with tunable particle sizes. Upon ultraviolet or near infrared excitation, the rare earth ions Ln3+ doped samples show the intense characteristic multicolor emissions coming from the Ln3+ activator ions. The particle size-dependent luminescence properties of the Ln3+-doped spherical samples are also investigated in detail. The as-fabricated LED devices prepared by the phosphors and LED chips can exhibit characteristic emissions of activator ions, which provides direct evidence that the as-synthesized phosphors may be potentially applied in LEDs, optoelectronics, and nanodevices.