新穎稀土硼酸鹽與鋅酸鹽螢光體之製備

Abstract

本研究以固態合成法於氫氣氣氛中成功製備分別摻入Ce3+或Eu2+為活化劑的CaY(BO3)O、Sr3Y(BO3)3、Ca4Y(BO3)3O、Ca4Gd(BO3)3O、Ca4Lu(BO3)3O、BaLuAlZn3O7與SrLuAlZn3O7等七種不同螢光體，稀土離子分別取代各主體中的Y3+、Gd3+、Lu3+、Ba2+、Sr2+等離子格位，經X光繞射分析確認主體晶相不會因Ce3+或Eu2+之摻入而改變。 上述螢光體中，稀土離子與過渡金屬Mn2+離子所取代格位的配位數分別介於四至九之間，而Ce3+激發波長為300~400 nm(峰值350 nm)，放射波長介於420 nm至450 nm的藍光；Eu2+離子激發波長為300~450 nm(峰值400 nm)，放射波長為520 nm的綠光。本研究並探討Ca4Y(BO3)3O:Ce3+,Mn2+中能量轉移的機制，其中Ce3+為敏化劑而Mn2+為活化劑，藉由能量傳遞以探討增強Mn2+發光之可行性。色度量測顯示上述螢光粉分別發射藍光、藍綠光、綠光及橘紅光等色光，預期將可提供紫外白光發光二極體應用的新選擇，本論文中部分螢光體更具有照明應用的潛力。

Novel phosphors with compositions of CaY(BO3)O:Ce3+, Sr3Y(BO3)3:Ce3+, Ca4M(BO3)3O:Ce3+ (M = Y, Gd, Lu), and MLuAlZn3O7:Eu2+ (M=Ba,Sr) were synthesized by solid state method. The crystal structures of host materials were found to retain after doping of rare earth ions by comparing X-ray data of the samples to those reported in database. We have also analyzed the structure of the hosts and relevant luminescence behaviors. In this research, rare-earth ions were found to substitute and enter the cation sites with four to nine in coordination numbers. The wavelength of blue emission was found to be 420-450 nm in the case of Ce3+-doped phosphors; whereas that is 520 nm in Eu2+-doped phosphors showing a green emission. Additionally, the C.I.E. chromaticity coordinates show that these phosphors emit hues including, blue, green, and orange red, respectively.