Preparation and Characterization of MgAl2O4 Phosphor by Sol-Gel Method

• Main Authors: Huang, si-yu, 黃思瑜
• Other Authors: Teoh, Lay Gaik
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/vfbsyr

碩士 === 國立屏東科技大學 === 機械工程系所 === 106 === In this experiment, magnesium-alumina spinel (MgAl2O4) was prepared by sol-gel method. The effects of different concentrations of Mn ions (1~10 mol%) and calcination temperature on the properties of the powder were investigated. The research focuses on the design and synthesis of materials, including grain size, surface morphology, and crystal structure and spectrometry. The experimental results by XRD show that the structure of MgAl2O4 is hexagonal spinel structure (Fd-3m, 227) can be formed under the calcination temperature of 700 °C for 2 hours. The higher the temperature of the calcination, the larger the grain size, and the grain size is about 5-25 nm, which belongs to the nanocrystalline structure and observed by TEM analysis. The absorption spectrum shows an absorption peak at 209 nm, which is caused by Mn2+ charge transfer (CT), and in the range of 250-360 nm, the Mg2+ position (A position) and the Al3+ position (B position) are exchanged at the time of arrangement or replace the resulting absorption band associated with the cavity and defect center. Irradiation at a radiation wavelength of 407 nm, excitation peaks at 250 nm, 283 nm, 302 nm, and 360 nm, and luminescence of oxygen vacancies in the magnesium metal lattice of the host material. The luminescence peak of the doping Mn ion is weakened, which may be related to the concentration quenching effect caused by the excessive impurity concentration. The pure MgAl2O4 powder sample at a calcining temperature of 800 °C had the most saturated blue color, and the chromaticity coordinates were (x = 0.174, y = 0.078).