Preparation And Luminescence Of The Novel And Single Matrix Phosphors For White Light-emitting Diodes

The white light-emitting diodes(W-LEDs) are widely applied in every field, such as three-dimensional display, biomedicine, and illuminating systems. Up to now, there exist the problems of red shift, different phosphor’s decayed cycles and re-absorption in the mature LED technology. These problems all affect the luminous efficiency and color rendering of white light. However, the single-phased white light emitting phosphors can effectively solve these problems.In this paper, the single-phased DC and UC white light emitting phosphors Ba Ca2In6O12 : Eu3+ and Ba In6Y2O13:Yb3+, Er3+,Tm3+ were prepared by the high temperature solid state reaction method and sol-gel method. By calculating the average Eu3+–Eu3+ distances of different substrate materials, and investigating the influence of the doping concentration and temperature on the luminescence properties, Ba Ca2In6O12 : Eu3+ phosphors achieve white light at higher Eu3+ concentrations. Meanwhile, we studied the UCL properties and UC efficiencies of the Yb3+, Er3+ and Tm3+ tri-doped and biphasic samples by operating dopant concentrations and excitation densities under 971 nm LD excitation, finally we obtain the efficient UC white light. Then these samples were done the simple encapsulation, respectively. Its main contents and results are as follows:(1) Heavily Eu3+-doped Ba Ca2In6O12 phosphors were prepared by conventional solid-state reaction. Its photoluminescence properties as single-phased white light emitting phosphors were investigated under different Eu3+ doping concentrations. The theory of concentration and thermal quenching were investigated. The data indicate that when single-phased phosphors doped the same activating agent, Ba Ca2In6O12: Eu3+ phosphors achieve more efficient white light at higher Eu3+ concentrations than other materials.(2) Ba In6Y2O13: Yb3+/Er3+/Tm3+ phosphors were synthesized by a sol-gel method. We studied the UCL properties and UC efficiencies of the Yb3+, Er3+ and Tm3+ tri-doped and biphasic samples by operating dopant concentrations, excitation densities and temperatures under 971 nm LD excitation. The dependence of the emission power and the up-conversion efficiency on the excitation density was studied by a efficiency test measurement system. The obtained data showed our samples own the highest UC efficiency of ~0.38% and stronger emission power than the materials previously reported phosphors, obtaining the efficient UC white light.