Preparation Of Rare Earth Doped Phosphates And Study On Their Luminescent Properties

As the advent of fourth generation lighting, LED has more advantages than previous generations, and fit the worldwide energy saving requirements, it gaining more and more attention. As one of the key component fore LED, rare earth florescent material’s quality directly affects the performance of the merits LED. Phosphate is a very stable chemical and physical properties of a class of compounds, they can transmitted ultraviolet region energy to activation center, and as a luminescent substrate it has a high luminous efficiency. This paper selects phosphate matrix, synthesized two rare earth luminescent materials under near-UV excitation by solid state method. We also conducted a study of its lattice structure, optics properties and mechanism of electron transitions.As the Luminescent material’s matrix, Ca9Tb(PO4)7 has an emission spectrum in the near-UV excitation. There are four emission peaks, respectively, at 487,543,585 and 620nm.We doped Eu3+,since Eu3+ and Tb3+ are all the rare earth ions, which have similar properties and atomic radii, so Eu3+ replaced Tb+. Eu3+ has a relatively narrow emission spectrum peak in this matrix, at the peak at 614nm. When Eu3+concentration increased gradually, Eu3+ luminescence characteristics of gradually increased.365nm excitation with different proportions of the sample, the color of a gradual transition from green to red, to achieve a color tunability. To Ca9Tb (PO4)7 incorporated Eu2+, because of Eu2+ and Ca2+ have similar ionic radii, Eu2+ replaced Ca2+. Besides, experiment found Eu2+ ions for Tb3+ energy transfer effect.Due to blue-green on blue and green emission peaks are strong, and the excitation spectrum of the near-ultraviolet region is wider than the commercial phosphors that can be used to near-UV LED chips. It is a very bright prospect of having luminescent materials.To KCaP3O9 matrix respectively incorporation Eu3+/Eu2+/Ce3+/Tb3+.From the perspective of ionic radii, we know that each of rare earth ions mainly replaced the position of Ca2+. KCaP3O9:Eu3+ at 590 and 610nm has two relatively narrow emission light, the optimum doping concentration is 0.5%. KCaP3O9:Eu2+ has a light emission in the 400-500nm with a peak at 439nm, the optimum doping concentration is 2%. Lluminescence of KCaP3O9: Ce3+ is in the 300-420nm and 600-800nm,peak located 332 and 652nm respectively, the optimum doping concentration of 0.5%. KCaP3O9:Tb3+ has total of nine peak, located at 375-625nm. Because of different emission mechanisms, optimal doping concentration is 1% and 2%, respectively. Selecting the optimum doping concentration, we incorporate into KCaP3O9, only Ce3+ energy absorption in the ultraviolet region can almost pass Tb3+, increase its luminous intensity.