Preparation And Luminescence Characteristics Of NaYF₄:Yb³⁺,Ho³⁺/PbF₂:³⁺NaYF₄:Yb³⁺,Ho³⁺/PbF₂:Er³⁺ Up-conversion Materials

With the increasing of seriousness environment and resource problems in global, to find a new kind of energy has been a primary problem for us. Solar power generation technology has been paid high degree of attention at home and abroad for its clean and non-polluting advantages.Up-conversion solar cell, as one of the third generation solar cells can broaden the absorption spectrum, is expected to improve the traditional battery conversion efficiency.Up-conversion materials, which can change the energy and frequency of the photon, are the core component of the system. NaYF4:Yb3+, Ho3+and PbF2:Er3+particles were prepared by a hydrothermal method in this paper, for the purpose of getting up-conversion materials applied to solar cells.With NaYF4as matrix and disodium edentate as surface completing agent, NaYF4:Yb3+, Ho3+particles with different grain sizes were synthesized. It is found that with the decrease of NaF/NH4HF2ratios in solution, the radial length of NaYF4:Yb3+, Ho3+prismatic particles is about4.5-5μm. And the axial length of the particle increase from5-15μm. The crystal is a hexagonal phase structure by XRD pattern. Taking980nm laser as the excitation source, the up-conversion emission peaks could be observed at approximately540,644and749nm. Up-conversion mechanism was discussed in detail. The experiments discussed the impacts of the doping concentration, particle size and reaction temperature on the material up-conversion spectrum. Based on the method of enhanced fluorescence up-conversion, Ag&NaYF4:Er3+luminescent materials were synthesized in the experiment, whose luminous intensity higher than that of NaYF4:Er3+.PbF2as matrix, PbF2:Er3+up-conversion particles were also synthesized by a hydrothermal method. The particles are present the spherical particles with tiny holes on the surface. After Er3+doping, the PbF2phase was transformed from an orthogonal to a cubic structure, and the grain size decreased from micro to nano. The up-conversion emission peaks could be observed at approximately540,660,800and980nm. The experiments discussed the impact of rare earth doping concentration, annealing temperature on the luminescent properties of materials. Optimum doping concentration of Er3+was4mol%and the thermal annealing contributed to the enhancement of the emission.