Upconversion Luminescent Properties Of Er³⁺ In Lanthanum Oxyfluoride Powders

The interest in rare earth ions-doped nanocrystals have renewed by their unique optical properties. These nanomaterials have sharp emission lines arising from the intra4f transitions with long lifetimes, and superior photo stability, due to the effective shielding of the4f orbitals by the higher lying5s25p6orbitals. Nanocrystals owe the properties of small size and the surface influence. Because of their unique luminescent properties, the upconversion nanocrystals doped with rare earth ions have important applications in many areas such as lasers, near-infrared quantum counting devices, detection of bimolecular, fiber communications, lighting industry and display systems, anti-counterfeiting technique. Searching good rare earth ions, improving the structure of the nanocrystals, developing more stable matrix material has been one of hot topics now.The matrix material is one of the important factors which influence the upconversion luminescent properties. The oxyfluoride which has both of good features of the fluoride and oxide is perfect fluorescence matrix material, and is good for improving the efficiency of upconversion luminescence.This paper described that the LaOF:Er3+and LaOF:Er3-,Yb3+were prepared by modified solid-state reaction, with a new up-conversion luminescent material LaOF. X ray diffraction (XRD) were carried out on the powders for phase identification to make sure the annealing temperature of the tetragonal and hexagonal structure, and compare the two structures of light-emitting luminous efficiency. The up-conversion emissions excited by a980nm diode laser produced green, and red emission bands, which were corresponding to the transitions of2H11/2â†'4I15/2,4S3/2â†'4I15/2,4F9/2â†'4I15/2of Er3+ions, respectively, analysing upconversion emission spectra and discussing the upconversion physics mechanism; The upconversion intensity dependence of excitation power, and the energy distribution of the upconverted emission spectra dependence of concentration of Er3+or Yb3+was discussed.