Optical Spectroscopy Properties of KMgF3:Eu2+ Nanocrystals and Powder Synthesized by Microemulsion and Solvothermal Process1

Nanocrystals and powders of KMgF3 doped with Eu2+ were synthesized by the microemulsion method and the solvothermal process, respectively. The emission and excitation spectra of KMgF3:Eu2+ phosphors were measured and compared with those of the samples synthesized through a solid state reaction, Bridgman-Stockbarger method, and mild hydrothermal technique. The KMgF3:Eu2+ samples synthesized by means of the microemulsion method and the solvothermal process show only a sharp emission peak located at 360 nm in the emission spectra, which arises from the f→f(6P7/2→8S7/2) transition of Eu2+. The broad emission bands appear at 420 nm, which arises from Eu2+ ← O2− cannot be observed (in the mild hydrothermal and single crystal samples, the emission peak at 420 nm besides the emission of Eu2+ at 360 nm is observed). In the excitation spectrum of the KMgF3:Eu2+ samples synthesized by the microemulsion method and the solvothermal process, the excitation peaks show an intensive blue shift. The blue shift can be attributed to the lower oxygenic content in the KMgF3:Eu2+ samples synthesized by the microemulsion method and the solvothermal process.