Preparation And Near-Infrared Luminescence Of Novel Nd³⁺ Doped Phosphors

There is highly considerable attention on near-infrared(NIR) luminescence of Nd3+,due to its many advantages such as strong penetrability,narrow linewidth and free of background for biological analysis. However, the NIR luminescence intensity of Nd3+ doped in inorganic materials is still weak, which is difficiult for its application. It is an important way to enhance the luminescence intensity through the energy transfer between sensitizer and Nd3+. Eu2+ is an important sensitizer and activator with allowed 4f-5d electric dipole transition for luminescence, which is highly efficient absorb and emission and transfer the energy to other ionic. The passage contributes to prepare novel NIR luminescence materials doped Nd3+ and discusses the energy transfer mechanism between Eu2+ and Nd3+. The experiments as follows:Near-infrared luminescence material Ca2BO3Cl:Eu2+,Nd3+ was synthesized by high temperature solid state method. All results show that near-infrared luminescence of Nd3+ could be greatly enhanced codope Eu2+. There is the greatest NIR luminescence when the concentration of Eu2+ and Nd3+ is 0.03,0.05, respectively. The nonradiation energy transfer from Eu2+to Nd3+ has been confirmed.NIR luminescence phosphors Ca3SiO4Cl2:Eu2+,Nd3+,Ca8Mg(SiO4)4Cl2:Eu2+, Nd3+ were prepared by high temperature solid state method. It was found that Eu2+ has efficiently sensitized the NIR luminescence of Nd3+. The concentration of Eu2+ and Nd3+ effect on luminescence intensity was investigated and relationships between sintered temperature, sintered time and luminescence intensity were also studied. Such as Ca8Mg(SiO4)4Cl2:Eu2+,Nd3+, NIR luminescence intensity firstly increased with Eu2+ concentration, then reduced, the optimal concentration is 0.10. The phosphors sintered at 1100℃for 3 h give the strongest NIR luminescence intensity. The energy from Eu2+ efficiently excited transfer to the lever of Nd3+, the emission intensity of Nd3+ is greatly enhanced.Phosphors Sr4Si3O8Cl4:0.08Eu2+,0.08Nd3+ were synthesized by high temperature solid state method. The NIR luminescence of Nd3+ could be efficiently sensitized by Eu2+, the emission intensity of Nd3+ enhanced 10 times, the energy transfer efficiency between Eu2+ and Nd3+ is 19.7%. Series phosphors codoped Ca2+ and Mg2+ in Sr4Si3O8Cl4:0.08Eu2+,0.08Nd3+ have been studied. NIR luminescence intensity increased with the Ca2+ concentration and reduced with the Mg2+ concentration. Series efficient green or blue phosphors LiSrPO4:Eu2+,LiCaPO4:Eu2+,KCaPO4:Eu2+>,NaCaPO4:Eu2+ have been prepared by solid state method, the prepared conditions were optimization. Results show that there are two different emission centers in LiSrPO4:Eu2+ host with increased Eu2+ concentration. LiCaPO4:Eu2+ is a novel efficient blue-emitting phosphor. The emission intensity from KCaPO4:Eu2+ was enhanced by doping Y3+. Furthermore, NIR luminescence phosphors LiSrPO4:Eu2+,Nd3+,LiCaPO4:Eu2+,Nd3+,KCaPO4:Eu2+,Nd3+,NaCaPO4:Eu2+,Nd3+ have been studied. The effect of emission wavelength from Eu2+ on NIR luminescence of Nd3+ was investigated. The effects of sintered temperature, sintered time and concentration on NIR luminescence were also investigated. The energy transfer mechanism between Eu2+ and Nd3+ was discussed.