Nanocrystals and powders of KMgF_ 3 doped with Eu~ 2+ were synthesized by the microemulsion method and the solvothermal process, respectively. The emission and excitation spectra of KMgF_ 3 ∶Eu~ 2+ phosphors were measured and compared with those of the samples synthesized through a solid state reaction, Bridgman-Stockbarger method, and mild hydrothermal technique. The KMgF_ 3 ∶Eu~ 2+ 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(~ 6 P_ 7/2 →~ 8 S_ 7/2 ) transition of Eu~ 2+ . The broad emission bands appear at 420 nm, which arises from Eu~ 2+ ←O~ 2- cannot be observed(in the mild hydrothermal and single crystal samples, the emission peak at 420 nm besides the emission of Eu~ 2+ at 360 nm is observed). In the excitation spectrum of the KMgF_ 3 ∶Eu~ 2+ 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 KMgF_ 3 ∶Eu~ 2+ samples synthesized by the microemulsion method and the solvothermal process.
Calcium fluoride nanoparticles were synthesized by water/cetyltrimethylammonium bromide (CTAB)/2-octanol microemulsion systems. X-ray powder diffraction analysis showed that the products were a single phase. The result of scanning electron microscopy confirmed that the average sizes of the calcium fluoride particles were below 100 nm in diameter. With decreasing water content and reaction time, the particle sizes decreased.
