奈米與塊材硫鎵酸鹽螢光體之製備、微結構與發光特性之研究

Abstract

奈米與塊材硫鎵酸鹽螢光體之製備、微結構 與發光特性之研究 學生：郭信甫 指導教授：陳登銘博士 國立交通大學應用化學研究所 摘要 本研究分別藉由熱溶劑法與固態法成功地合成奈米與微米級ZnGa2S4螢光體，其主旨在探討奈米與微米螢光體的合成原理、微結構、發光特性與發光機制之相互關係。 在熱溶劑法製程中，藉由溶劑之控制，我們已成功製備球狀(晶粒粒徑80~100 nm)與棒狀(外徑5-10 nm、長軸50-100 nm)兩種不同微結構的奈米ZnGa2S4: M( M = Mn2+, Eu2+, Tb3+)螢光體。針對奈米ZnGa2S4: M，本研究除探討其激發與發射光譜及衰減期之外，舉凡反應溫度、活化劑濃度、敏化劑Pb2+之摻雜、溶劑填充率與反應物種類與濃度等因素對其發光特性之效應亦進行深入研究。當ZnGa2S4:M晶粒縮減至奈米時，由於尺寸所導致的量子侷限效應已在激發光譜中發現；此外，本研究並利用已知模型與公式，估計具有不同晶粒尺寸奈米ZnGa2S4:M螢光體的能隙值。 另一方面，本研究也成功地發展固態新製程，配合硫化氫輔助退火以製備微米級高結晶性、高亮度SrGa2S4:R ( R = Eu2+, Ce3+ )，並藉以探討ZnGa2S4:M螢光體製程參數、微結構與發光特性之相互關係，依據所提的發光機制，配合簡單理論計算，其結果可與對應螢光光譜相互印證，進而建構SrGa2S4:R與ZnGa2S4:M兩系列螢光體可能的發光模型，並試圖藉以詮釋其發光機制。

Syntheses, Microstructures, Photoluminescence of Nano- and Bulk-Thiogallate Phosphors Student：Hsin-Fu Kuo Advisor：Dr. Teng-Ming Chen Institute of Applied Chemistry National Chiao Tung University ABSTRACT To investigate the correlation among the principles of synthesis microstructure, luminescence and relevant mechanism, we have prepared both microcrystalline and nano-sized ZnGa2S4 phosphors via solvothermal and solid-state routes, respectively. By selecting appropriate solvents in the solvothermal synthesis, we have successfully synthesized nanophosphors of ZnGa2S4:M ( M = Mn2+, Eu2+, Tb3+) with spherical (□ = 80~100 nm) and rod-shaped (□ = 5-10 nm and length = 50-100 nm) microstructures, respectively. We have investigated the photoluminescence (PL), excitation (PLE) spectra and decay lifetime for ZnGa2S4:M nanophosphors. The effect of synthetic temperature, concentration of activator and reactants, doping of sensitizer, filling percentage of solvents and the source of reactants on the luminescence has also been investigated. The quantum confinement effect attributed to the nano-dimensions has been observed in the PLE spectra of ZnGa2S4:M nanophosphors whose energy gaps were also roughly estimated based on known models and formula. In addition, attempts have also been devoted to prepare bulk SrGa2S4:R ( R = Eu2+, Ce3+ ) phosphors with high crystallinity and brightness and investigate their relevant processing conditions, microstructures and luminescence by employing solid-state processes, followed by high-temperature annealing under H2S atmosphere. Based on the proposed mechanism of luminescence in our investigation, we have carried out simple theoretical calculations and the results are correlated with the experimental PL and PLE spectra for consistency. In the end, we hope to establish the possible models of luminescence for bulk SrGa2S4:R and ZnGa2S4:M phosphors and, furthermore, the rationalization of relevant mechanism has also been attempted.