A Study on the Synthesis and Luminescence of Novel Halometalborate and Germanate phosphors for White-Light Emitting Diodes

• Main Authors: Wu, Si-Chi, 吳思琦
• Other Authors: Chen, Teng-Ming
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/44144848534452433572

碩士 === 國立交通大學 === 應用化學研究所 === 98 === On this study, we have successfully synthesized several novel phosphors with compositions of BaAlBO3F2:Ln (Ln = Ce3+, Eu2+) , Ba2AlB4O9Cl: Ln (Ln = Ce3 ) , Ba2GaB4O9Cl: Ln (Ln = Ce3+ , Eu2+) , Sr3(AlO4)F: Ce3+ and Sr3(GaO4)F: Ce3+ by using solid-state method under H2/Ar reduction atmosphere and phosphors of Na2MGe6O14: Mn 4+ (M=Ca , Sr) by using solid-state method in the air. The crystal structure , luminescence and chromaticity properties of these phosphors were characterized by diffuse reflectance spectroscopy (DR), X-ray diffraction (XRD) and photoluminescence spectroscopy. This research is divided into six chapters. We first report the optimization of synthetic condition for all phosphors and the analysis of XRD profiles. We then investigated the spectroscopic properties of Ce3+- doped phosphors and the correlation between dopant sites and the emission wavelength. Furthermore , the Ce3+→ Tb3+ energy transfer in the BaAlBO3F2 : Ce3+, Tb3+ system was also studied and the energy transfer mechanism has been determined to be dipole-diple type interaction. On the other hand , the luminescence properties of Eu2+ -activated BaAlBO3F2 and Ba2MB4O9Cl (M=Al , Ga) have also been investigated , which were rationalized by considering covalency effect and crystal field strength. Red emitting Mn4+ - activated Na2MGe6O14: Mn 4+ (M=Ca , Sr) were also studied. Finally , the thermal-quenching behaviors for all phosphors were investigated for evaluating theis potential application in the fabrication of white LEDs.