奈米稀土硫氧化物螢光體的製備、微結構與發光特性之研究

Abstract

本研究利用熱溶劑法配合高溫(300-700℃)硫化氫退火製程，分別成功地合成兩系列稀土離子(如:Eu3+, Tb3+, Pr3+, Sm3+, Dy3+)激活球狀與棒狀形貌的奈米R2O2S (R = Y, Gd)螢光體。 為掌握關鍵的製程條件，以期能掌握奈米螢光體之微結構與相關材料發光特性，本研究探討了反應物來源及濃度、合成溫度、溶劑種類與溶劑填充率、活化劑摻雜濃度與表面修飾等製程參數，對奈米R2O2S微結構與發光特性所產生之效應。 穿透式電子顯微鏡影像分析顯示:當使用硝酸釔/硫脲為熱溶劑合成起始物且溶劑為甲醇與乙二胺時，可分別合成外徑為60 nm之球狀以及直徑為10 nm、長度為1.5 □m的棒狀奈米Y2O2S:Tb螢光體；但當以甲醇/乙二胺(50:50, v/v)為溶劑時，則可合成直徑與長度分別為30 nm與1.5 □m之棒狀奈米Y2O2S:Tb螢光體。此外，直徑與長度分別為20 nm與4 □m棒狀奈米Gd2O2S:Tb螢光體，則可由使用乙二胺為溶劑的合成反應中獲得。

This research demonstrated the successful synthesis of two series of rare-earth (i.e., Eu3+, Tb3+, Pr3+, Sm3+, Dy3+) -activated R2O2S (R = Y, Gd) via a solvothermal route at 150℃, followed by H2S-annealing at elevated temperatures (i.e., 300-700℃). To establish the appropriate processing conditions, we have investigated the microstructure and luminescent properties of R2O2S nanophosphors, as a function of source and concentration of starting materials, synthetic temperature, solvents and their filling rate, activator concentration and surface modification. As indicated by TEM image analyses, spherical (60 nm in diameter) and rod-shaped (10 nm in diameter and 1.5 □m in length) nanophosphors of Y2O2S:Tb have been prepared by solvothermal reactions using methanol (MeOH) and ethylenediamine (en) as a solvent, respectively, followed by H2S annealing.. Furthermore, a rod-shaped nanophosphor of Y2O2S:Tb with 30 nm in diameter and 1.5 □m in length has been synthesized by using MeOH/en mixture (50:50, v/v) as a solvent. On the other hand, rod-shaped nanophosphors of Gd2O2S:Tb with 20 nm and 4 □m in diameter and length, respectively, have been obtained by using en as a solvent in a solvothermal reaction.