在Sapphire 基材上以電化學沉積YAG 螢光薄膜
A novel method of electrolytic Y3Al5O12 (YAG:X, X=Ce, Eu, Tb) phosphor thin-film coating on sapphire was investigated in yttrium, aluminum, cerium, europium and terbium nitrate solution. By means of X-ray diffraction (XRD), scanning electronic microscopy (SEM) observation, and cathodic polarization tests, the most efficient potential of deposition was found in the region between -1.2 V~-1.5 V. The YAG phosphor thin-film was successfully synthesized by the cathodic deposits were heat-treated at 1200 ℃ for 4 hours. The excitation photoluminescence (PL) spectra of Ce3+ in YAG consists of a strong maximum at about λ=520~530 nm that show yellow emission peak, and a red emission was observed at about λ=595~700 nm by additional Eu3+. The excitation PL spectra monitored inλ=480~500 nm with the amount of Tb3+ and that show green emission peak. The fabrication of YAG phosphor thin-film will be useful to improve the emission intensity of the white LEDs in the future.由電解沈積陰極的電位—電流關係圖、X光繞射分析、SEM 觀察及實驗反應的經驗式我們可以知道要在導電的sapphire(氧化鋁單晶)基材上電解沈積合成燒結YAG 螢光薄膜所需之各類氫氧化金屬,其合適的電解沈積電位為-1.2 V~-1.5 V,我們利用電化學沈積法可以成功地合成欲燒結成YAG 螢光薄膜所需之氫氧化金屬,將所合成之氫氧化金屬放入高溫爐以1200 ℃高溫燒結4 小時後,依據我們目前以光螢光激發(PL)這些YAG 薄膜的光譜結果,可以成功地得到YAG:Ce(λ=520~530nm)黃光螢光薄膜、YAG:Eu(λ=595~700nm)紅光螢光薄膜及YAG:Tb(λ=480~500nm) 綠光螢光薄膜,證明以新的電化學方法可以成功製備YAG 螢光薄膜,相信這些研究成果未來應用在研發提昇白光LED 發光效能上有極大之助益。
對號入座
After reading “CKSH Communication 20 “, we are interested in Question 5 . We try to explain that in all the No. Crunches, whether we can put the numbers in the No. Crunches any certain position. We specify the question, according to the “Point Symmitry Homing” in mxn No. Crunches, to find the correlated characters of the rules. Finally, we find a “switch” – we can get the better way to rotate the numbers quickly by some programs.從「建中通訊解題」第20 期第5 題出發,本研究嘗試去解釋對所有的數字轉盤而言,是否能將其中的數字歸位到任意指定的位置?接下來將題目特殊化,藉由m× n 數字轉盤的「點對稱歸位」,尋找遊戲規則衍生出的相關性質。最後,利用研究出的性質找到一個「判斷式」可藉由程式設計,快速的找到較佳轉法。