Facile Synthesis of Yb3+- and Er3+-Codoped LiGdF4 Colloidal Nanocrystals with High-Quality Upconversion Luminescence

Herein, we synthesized high-quality colloidal nanocrystals of Yb3+/Er3+-codoped LiGdF4 with intense green emission by using a facile route and turning the associated reaction parameters. Moreover, we probed the effects of reaction conditions on nanocrystal properties (crystal structure, morphology, and luminescence) and gained valuable mechanistic insights into nucleation and growth processes. Sample purity was found to depend on LiOHH2O concentration, reaction temperature, and time, which allowed us to manipulate sample purity and thus obtain species ranging from mixtures of LiGdF4:Yb3+/Er3+ with GdF3 to pure tetragonal-phase LiGdF4:Yb3+/Er3+. Investigation of upconversion luminescence properties and the luminescence lifetime of as-prepared samples revealed that LiGdF4 is a promising host material for realizing the desired upconversion luminescence.