Study On Synthesis And Photoluminescence Of High-brightness Luminescent Materials(Y,Gd) BO₃:Eu³⁺

The study of properties of phosphors is essential to improve the performance of the high-definition color PDP. Nowadays, (Y,Gd)BO3:Eu3+ is recognized as one of the best commercial red phosphors for PDP due to its high VUV absorbency and extraordinarily high luminescent efficiency under VUV excitation. However, all of these advantages do not make (Y,Gd)BO3:Eu3+ as a desired VUV phosphors because of its luminescent efficiency and chromaticity problem. So the research on the improvement of existing phosphors or the development of new red phosphors is necessary. Experimental and theorital research is contained in this thesis:A) the improvement of orthoborate phosphor (Y,Gd)BO3:Eu3+ with the incorporation of several cations; the synthesization and optical properties of series new borate phosphors; B) the calculation of the electronic structure of YBO3 and the optimization of industrialization preparation technology.In order to improve the luminous intensity, Y0.75-xGdxAl0.10BO3:0.10Eu3+,0.05R3+ (R=Sc,Bi; 0.00≤x≤0.45) are synthesized by solid-state reaction. Their luminescent properties under ultraviolet (UV) and vacuum ultraviolet (VUV) excitation are researched. The results indicate that with the incorporation of Al3+,Sc3+,Bi3+ and Gd3+, the higher intensity and better chromaticity are obtained because Gd3+ and Bi3+ played an inter-mediate "bridge" between the sensitizer and the activator (Eu3+) in energy transfer to produce light in (Y,Gd)BO3:Bi3+, Eu3+ system more effectively. The best chromaticity as well as the strongest luminescence can be obtained when 5%mol Al3+,5%mol Bi3+ and 25%mol Gd3+ are co-doped into the host lattice of YBO3:Eu3+, and the emission intensity came to its maximum which was nearly 115% compared to the red commercial phosphor (Y,Gd)BO3:Eu3+. On the other hand, (Y0.65-xGd0.25Mx) BO3:0.10Eu3+(M=Li, Na,K; 0.00≤x≤0.10) are synthesized by solid-state reaction. Their with the incorporation of Li+, Na+ or K+, the high symmetry around Eu3+ is destroyed and the ratio of red emission to orange one increased, leading to better chromaticity. (Y,Li)0.65Gd0.25BO3:0.10Eu3+ shows the best chromaticity and highest luminescent intensity which was nearly 105% compared to the red commercial phosphor (Y, Gd)BO3:Eu3+.