Rare earth doped red phosphors Y_2O_3 Preparation and Luminescent Properties

Title: Rare earth doped red phosphors Y_2O_3 Preparation and Luminescent Properties
　　Author: Li Xiaoliang
　　Degree-granting unit: Dalian Maritime University
　　Keywords: homogeneous precipitation;; yttria;; red phosphor;; display
　　Summary:
　　Upconversion luminescence shows because is small, colorful, long life, low cost, especially to achieve true three-dimensional display, therefore, has become a hot research in recent years. High brightness, high resolution up-conversion light-emitting display needs to have a high luminous efficiency, high purity and good morphology of fluorescent color (best ball) Magnetic lifter  of fine red, green and blue color-conversion luminescent particles. For red light-emitting materials, the internationally recognized Y2O3: Yb3 +, Er3 + is an ideal choice, but most such commercial phosphor prepared by solid-phase, there is a large particle size, easy to agglomerate, morphology does not rules and other issues, so the up-conversion light-emitting display the application subject to certain limitations. On the other hand, Y2O3: Eu3 + is a very good performance of the red down-conversion phosphor, has been widely used in color television picture tube, three-color fluorescent lamps and so on. With the rapid development of high-resolution display technology, the Y2O3: Eu3 + also proposed a new requirement that high luminous efficiency, small particle size, morphology is spherical. In view of this, the paper also carried out spherical, ultrafine Y2O3: Yb3 +, Er3 + and Y2O3: Eu3 + phosphor display with luminous efficiency of the preparation and study, the main research contents and results are as follows:
　　1, were prepared using homogeneous precipitation in the 100-200nm particle size range of spherical Y2O3: Yb3 +, Er3 + upconversion red particles. Of Yb3 + and Er3 + doping concentration is optimized, when the doping concentration of 6mol% Yb3 +-1.2mol% Er3 +, the sample of luminous intensity and color purity of red best. Studied the urea concentration, aging time, calcination temperature and other process parameters on particle upconversion luminescence intensity of the impact, and to determine the optimal experimental parameters. Found that the added Li2CO3 flux can greatly improve the sample of luminous intensity, when the adding amount of 10wt% (mass fraction), calcination temperature of 850 ℃, the samples of the red emission intensity can be increased about 13.6 times; by Y2O3: Yb3 +, Er3 + upconversion mechanism analysis to determine the red (4F9 / 2 → 4I15 / 2 transition), green (2H11 / 2,4 S3 / 2 → 4115 / 2) emission are the two-photon upconversion process.
　　2, were prepared using http://www.999magnet.com/products/131-magnetic-lifter homogeneous precipitation in the 100-200nm particle size range of spherical Y2O3: Eu3 + red down-conversion light-emitting particles. Determine the optimum doping concentration of Eu3 + is 8mol%, the best excitation wavelength of 254nm. Studied the urea concentration, aging time, calcination temperature and other process parameters on particle emission intensity of the impact, and to determine the optimal experimental parameters. Found in the sample after adding Li2CO3 red emission intensity can be increased about 32%, the best dosage 8wt%, optimum calcination temperature of 900 ℃. The results show that the concentration quenching curve, Y2O3: Eu3 + concentration quenching is caused by the exchange interaction.
　　Degree Year: 2010