MgF_2:Mn^(2+)合成及发光

SYNTHESIS AND LUMINESCENCE OF THE PHOSPHOR MgF_2:Mn^(2+)

本文首次报导了采用碱式碳酸盐和氟化铵一步合成MeF_2:Mn^(2+)长余辉材料新方法。研究了各种条件和Mn^(2+)浓度对荧光粉的影响,所得到的MgF_2:Mn^(2+)发射为橙红色,主峰在590nm,色度值为x=0.559,y=0.438,余辉大约200ms。荧光粉呈现均匀圆球状的颗粒,属于四方晶系。

This paper reports that the long persistence phosphor pf MgF2:Mn2+ is synthesized successfully at 900C. Authors suggest the use of magnesium carbonate basic and ammouium fluoride as starting materials, and the relationship expressed by the reaction equation:Mg(OH)2.4MgCO3.6H2O+ 10NH4F-MgF2 + 12H2O + 4CO2 + 10NH3 is studied as a function of preparation temperature. The optimum conditions for preparating the samples have been examined. It shows that the concentration of Mn2 + ion is about 0.5mole%.Emission spectra of MgF2:Mn2+ phosphor are measured from 400nm to 700 nm and that of a typical sample is shown in Fig.2. The emission color of the phosphor is orange-red with chromaticity x= 0.599, y = 0.438. The emission peaks for these samples occur at 590nm. The luminance varies with the voltage or current density (Fig.3 and Fig.4). The cathode luminescence characteristics of the samples are studied. Luminescence brightness and persistence of MgF2: Mn2+ phosphors are superior to P33 phosphors.In order to investigate the composition structure of the sample, X-ray diffraction (Cu-Ka), 50mA,40kV) analysis is performed (Fig.5). The structure of the sample belongs to the tetragonal system. It is found that the dominant composition phase is magnesium fluoride (MgF2). The matric composition phase of P33 phosphor contains not only magnesium fluoride but also potassium magnesium flouride (KMgF3). We can see that some small diffraction peaks in X-ray diffraction pattern. It has not been clear yet what are those peaks. Scanning electron micrographs of MgF2:Mn2+ phosphors show that-the average particle sizes are 3.5um. It is similar to that of determined results by means cf UV-200 type disk centrifugal particlemeters. Experimental results have indicated that the phosphor consists of the spherical particles and we can see the agglomerated phenomena of the samples. The display tubes coated with the MgF2:Mn2 + phosphor possibly can be used for the computer terminal display.