以溶膠-凝膠法製備矽酸鋅(Zn2SiO4)螢光體及其特性之研究

Preparation and Characterization of Zinc Silicate (Zn2SiO4) Phosphors by the Sol-Gel Methods

林明祥(Ming-Shiang Lin)

國立虎尾科技大學/電機資訊學院/光電與材料科技研究所/碩士(2007年)

摘要

本研究是以溶膠-凝膠法製備矽酸鋅摻錳或鈦之螢光膠體，並探討不同的溶膠濃度、摻雜劑量的多寡以及改變熱處理條件對於Zn2SiO4：Mn；Ti螢光膠體結構、結晶性、微結構、及發光特性之影響。
實驗製程方面，起始材料分別為金屬鹽類及金屬有機化合物，並摻雜錳或鈦，經由溶液的混合、水解、解膠、及縮聚合反應製備Zn2SiO4：Mn；Ti螢光膠體。實驗發現，改變水含量、電解質濃度、及摻雜劑量，均可形成清澈透明的溶膠與凝膠，但水含量、電解質濃度和摻雜劑量會影響溶液之膠化速率，且膠化時間隨著水含量、電解質濃度及摻雜劑量的增加而減短。改變水含量、電解質濃度、及摻雜劑量對於膠體的熱活化行為、結晶性及分子結構並無明顯之影響。
經乾燥後的膠體於熱處理700 oC後，均開始產生α-Zn2SiO4結晶，且結晶性隨著熱處理溫度的升高而增加。經熱處理溫度900 oC後，無摻雜及摻雜錳或鈦的膠體均具有介孔型的結構，其平均孔徑大小為 17 ± 1 nm，且平均孔徑隨溫度的增加有變大的趨勢。
摻雜錳或鈦的膠體，其放射波長分別位於525 nm (綠光)或450 nm (藍光)，而熱處理條件與摻雜劑量會顯著影響膠體的發光強度，且發光強度均隨著熱處理溫度的升高而增加，經熱處理溫度1200 oC後，摻雜錳劑量由0.1 % ~ 0.5 % 時，放射強度隨摻雜錳劑量增多而增加；當摻雜錳劑量超過0.5 %時，放射強度則隨摻雜錳劑量增加而降低。摻雜錳或鈦的膠體之衰減時間（τR）分別為17 ms和12 ms。

並列摘要

In this research, nanocrystalline manganese- and titanium-doped zinc silicate (Zn2SiO4：Mn；Zn2SiO4：Ti) phosphors powders were prepared by the sol-gel processes, respectively. The effects of solution concentration, dopant amount and heating temperature on the phosphor structures, crystallities, microstructures and luminescent properties were investigated and discussed.
In the experimental process, the precursors were metal salts and metal organic compounds. Manganese and titanium were used as dopants. The doped zinc silicate phosphor powders could be prepared by the procedures of mixing, hydrolysis, petization, and condensation reaction. Transparent sols and gels could be obtained from appropriate amounts concentrations of water, acidic electrolyte and dopants. It was observed that water concentration, electrolytes and dopant amounts could remarkable affect the gelation rate of solution. The gelation rates increased with increasing of water content, acidic electrolytes and dopant amounts. With different amount of water, electrolytes, and dopants, however the thermal activity, crystalline behaviors, molecular structures as well as the infrared spectra of powders did not show significant difference.
The dried powders began to form the α-Zn2SiO4 crystalline phase after heat-treatment at 700 oC, furthermore the crystallinity of the powders increased as the firing temperature increased. On heat-treatment at 900 oC, all the undoped and doped powders possessed mesopore structures with average pore sizes of 17 ± 1 nm. Their pore sizes increased with increasing firing temperatures.
The photoluminescence (PL) spectrum showed that the peak wavelength of the green and blue emission are at 525 nm and 450 nm for Zn2SiO4：Mn and Zn2SiO4：Ti, respectively. Moreover, the heating temperature and dopant amounts had a significant influence on the luminescent intensity of phosphor powders. The luminescent intensity of the powders increased as the firing temperature increased. After heat-treatment at 1200 oC, the luminescent intensity of the powders increased as the dopant amounts of 0.1 % ~ 0.5 %. The luminescent intensity of the powders decreased as the dopant amounts to exceed 0.5 %.The lifetime（τR）of Zn2SiO4：Mn and Zn2SiO4：Ti phosphors were 17 ms and 12 ms, respectively.

參考文獻

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