次微米級螢光粉噴霧乾燥製程之研究

Abstract

本研究藉由兩階段噴霧乾燥法成功地合成具有球狀、次微米級尺寸和非聚集性等優點之Y3Al5O12:Ce3+ 和 LaPO4:Ce3+螢光體，其主旨在探討次微米球狀螢光體的合成原理、微結構、發光特性與發光機制之相互關係。 本論文將噴霧乾燥法製備之 Y3Al5O12:Ce3+ 和 LaPO4:Ce3+與固態法製備之螢光體樣品作結晶度、微結構與光致發光光譜等特性之比較。比較噴霧乾燥法與固態法製程在相同的燒結溫度下，可合成較固態法純度和結晶度均佳之螢光體。以1200℃燒結之噴霧乾燥法製備Y3Al5O12:Ce3+與1100℃燒結之噴霧乾燥法製備LaPO4:Ce3+螢光體，依然維持其晶粒球狀、次微米級和非聚集的特性。光致發光光譜顯示: Y3Al5O12:Ce3+和 LaPO4:Ce3+ 螢光體之吸收或放射峰的強度與燒結溫度並非成正比的關係，但與粉體之晶粒形狀和聚集程度有密切的關係。 本研究亦探討溶液濃度、前驅物種類等製程變因，對於所製備螢光體微結構變化之效應，本論文已獲致以噴霧乾燥法製備Y3Al5O12: Ce3+和 LaPO4:Ce3+螢光體之最佳製程條件。

To investigate the correlation among the conditions of chemical synthesis, microstructure, and luminescence properties, we have prepared both microcrystalline spherical Y3Al5O12:Ce3+ and LaPO4:Ce3+ phosphors with submicron size and non-aggregating characteristics via a two-step spray pyrolysis route. The cystallinity, microstructure, and photoluminescence (PL) properties of Y3Al5O12:Ce3+ and LaPO4:Ce3+ phosphors have been compared and investigated as a function of processing conditions. In particular, the microstructures of the above phosphors were investigated as a function of precursor concentrations, types of precursors, temperature, and reaction durations. Two series of spherical submicron-sized non-aggregating Y3Al5O12:Ce3+ and LaPO4:Ce3+ phosphors with decent crystallinity have been prepared at 1200℃ and 1100℃ via a two-step spray pyrolysis route, respectively. As indicated by the PL spectra, the excitation and emission bands for Y3Al5O12:Ce3+ and LaPO4:Ce3+ phosphors are not positively correlated with the processing temperatures, but closely related with the grain morphology and degree of aggregation of the phosphors. With thorough investigations we have obtained the optimal processing conditions for preparing Y3Al5O12:Ce3+ and LaPO4:Ce3+ phosphors, which can be further used as a reference for future scale-up production.