新穎硼氮螢光材料之製備與發光特性之研究

Abstract

本研究主旨在開發激發波段約為350-460 nm可供製作白光發光二極體(LED)之新穎發射藍、綠與紅光氮化物/氮氧化合物螢光材料，以提供白光LED螢光粉應用之新選擇。 本研究以固態合成法製備五系列不同化學組成之硼氮螢光體，並利用X-射線粉末繞射、漫反射與螢光光譜分別進行其晶體結構與晶相分析、光學、色度與發光特性鑑定。上述螢光體大多主體皆具有自發光特性，而當分別摻入Eu3+、Eu2+或Ce3+為活化劑以取代各硼氮化合物主體中配位數介於四至六之鹼土陽離子格位時，Eu3+摻雜系列螢光體發射紅光；Eu2+或Ce3+分別摻雜的螢光體之發光，主要決定於主體共價性與晶場強度，特別是Eu2+及Ce3+離子5d軌域分裂強弱程度與其配位環境與點對稱。

For fabrication of white light light emitting diodes (LED), tis research is attempted to develop novel red-, green-, and blue-emitting boronitride phosphors with the excitation wavelength ranging from 350-460 nm. The boronitride phosphors were prepared by solid-state reactions and their crystal structure, phase purities, chromaticity and luminescence properties were characterized by powder X-ray diffraction, diffuse reflectance and photoluminescence spectra. Most of the as-synthesized boronitride phosphors were found to show self-activation. The rare earth ions were found to substitute and enter the cation site of the host with four to six in coordination. The Eu3+-doped phosphors were found to be mainly red-emitting. On the other hand, the luminescence of the Eu2+- and Ce3+-doped boronitride phosphors were found to emitting from yellow, blue to infrared and was highly dependent on the crystal field strength and covalency of the hosts, especially on the 5d orbital splitting and site symmetry of the Eu2+ and Ce3+ activators.