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Please use this identifier to cite or link to this item: http://ntour.ntou.edu.tw:8080/ir/handle/987654321/53381

Title: 長餘暉螢光體環境耐候性研究
Investigation on environmental durability for long lasting phosphors
Authors: Hsu, Ya-Wan
許雅紋
Contributors: NTOU:Department of Marine Engineering
國立臺灣海洋大學:輪機工程學系
Keywords: 綠色長餘暉;耐候性;核/殼結構螢光體;明視強度
green long afterglow;weather-resistance;core-shell phosphors;distinct
Date: 2019
Issue Date: 2020-07-02T08:20:58Z
Abstract: 白光照射後發射520nm綠色長餘暉的SrAl2O4:Eu2+,Dy3+ (SAO)螢光體易受空氣中的水氣與CO2甚至鹽份侵襲,在應用上需進一步做環境耐候性研究改進。固態法製備SrAl2O4:Eu2+,Dy3+螢光粒子,經泡水測試,發現螢光粒子無法承受太久的浸泡時間,僅1小時後的光致發光與長效性螢光已經衰減殆盡。為了克服SAO抗濕性的耐候問題?本研究對固態法製備的SAO採用B2O3披覆技術形成(SAO/BO)核殼式結構,使B2O3披覆層具有增進SAO光學特性及耐候性。 在泡水的加速實驗中,SAO/BO能延長水解時間至4小時仍具發光性質,12小時測試後產生水解反應形成SrCO3與Al2(OOH)2。為了SAO/BO實際室外應用之耐候性鑑定,SAO/BO核/殼結構螢光體與蝶谷巴特膠(DG)均勻混練成塗料,塗佈在壓克力基材上製作成試片。首先進行泡水加速實驗,泡水1週後仍能維持一定的光致發光與長效性餘暉強度,在足夠肉眼可視強度以上。進一步使用SAO/BO螢光體與蝶谷巴特膠(DG)混練的塗料,繪製成小丑魚夜光看板,將其置於高濕度、高鹽份之基隆海科館潮境海邊進行長時間耐候測試,也做為潮境觀光之亮點。同時取樣分析結晶、微結構、光致發光與長效性餘暉量測分析。經兩週後分析螢光體結晶強度約僅為測試前之20%。包覆SAO顆粒的非晶質B2O3層在兩週測試後出現劣化,使SAO顆粒曝露分離,但仍存披覆的B2O3殼層在SAO表面。第四週後結晶劣化趨於穩定,綠色SAO螢光體在蝶谷巴特膠(DG)與非晶B2O3保護下可具耐候性。對觀賞者來說,長餘暉效果最明顯感受是60秒內的視覺!小丑魚夜光看板承受環境實測下,十週後第10分鐘的餘暉強度都還在明視強度。本研究結果確認SAO/BO核/殼結構螢光體具有耐候性之長效保存性;結合蝶谷巴特膠(DG)混練成的塗料在高濕度、高鹽份的環境侵蝕下,十週後維持肉眼明視之穩定餘暉強度,證明核/殼夜光長餘暉塗料具有長時效耐候性,利於顯像、指標等之應用。
The long persistent phosphors of SrAl2O4:Eu2+,Dy3+ (SAO) emit green light of 520 nm wavelength after white light excitation. Such phosphors are sensitive to humidity, CO2 and high salinity environment attack. The weather-resistance is required for the phosphor applications. In this study, the solid-state method prepared SAO phosphors are immersing in water for accelerated life test. Such SAO phosphors are water-endurable only 1 hour to destroy the SAO structure and optical properties degradation. In order to improve the weather-resistance of the SAO phosphors, the SAO particles are processed by B2O3 coating to form the type of core-shell structure SAO/BO. The shell of B2O3 forms buffer layer to improve the optical properties and to protect the SAO from wet environment attack effectively. During the accelerated life test, the SAO/BO can endure the hydrolysis time to 4 hours but decomposes into SrCO3 and Al2(OOH)2 after 12 hours. For the outside environmental applications, the synthesized SAO/BO phosphors are mixed with Decoupage Glue (DG) to be a paste, then coating on some acrylic plates. They are subjected to accelerated life test firstly. The DG mixed samples maintain the long afterglow/photoluminescence brightness for distinct vision of human eyes after water immersion in one week. Further, the paste is painted as a kind of clownfish pattern on an acrylic plate to hang on the wall of a building in the National Museum of Marine Science and Technology (NMMST) by the Keelung beach. Those phosphor plates are subjected to weather-resistant test and compare to material analyses of crystal structure, microstructure and long afterglow measurement. The XRD intensity decreases to 20% peak intensity of original SAO/BO phosphor after two weeks test. The shell B2O3 surrounding SAO particles degrades after two weeks as to exposing the SAO particles. The B2O3 coverage is still coating on the SAO surface even four weeks exposure to the beach weather. The crystal degradation tends to stability after four weeks test. The DG and B2O3 layer play the role of weather-resistance for the SAO green long afterglow phosphors. Comparing the clownfish brightness with sampling data, it indicates the high emitting intensity at the first one minute recording. Generally, the most obvious vision impact on the human eyes is during the earliest time of 60 seconds. The results confirm the SAO/BO phosphors can stand up to high humidity and high salinity environment even ten weeks longer exposure. The stable afterglow intensity is sustained 10 minutes above distinct vision of human eyes. Thus, the B2O3 layer protected phosphors provide persistent intensity to weather-resistance for the display and indicator applications.
URI: http://ethesys.lib.ntou.edu.tw/cgi-bin/gs32/gsweb.cgi?o=dstdcdr&s=G004064Q003.id
http://ntour.ntou.edu.tw:8080/ir/handle/987654321/53381
Appears in Collections:[輪機工程學系] 博碩士論文

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