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http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/65042
標題: | 鈣鈦礦氧化物薄膜及其層狀複合結構之光電流表現 The Photocurrent Behavior of Perovskite Oxide Thin Films and Their Layered Structures |
作者: | Chia-Yu Fang 方家宇 |
指導教授: | 謝宗霖 |
關鍵字: | 光電流,光電極,heterojunction,層狀複合結構,SrTiO3,AgNbO3,(SrTiO3)x(AgNbO3)1-x, Photocurrent,Photoelectrode,Heterojunction,Layered structures,SrTiO3,AgNbO3,(SrTiO3)x(AgNbO3)1-x, |
出版年 : | 2012 |
學位: | 碩士 |
摘要: | 本研究討論異相反應光觸媒(heterogeneous photocatalyst)在光電極的應用,材料的選擇為鈣鈦礦氧化物SrTiO3、AgNbO3及其固溶體(SrTiO3)x(AgNbO3)1-x薄膜,著重於觀察這三者間heterojunction的效應。實驗結果顯示,SrTiO3與AgNbO3所形成之層狀複合結構(SrTiO3/AgNbO3),其光電流表現較SrTiO3與AgNbO3薄膜皆來得優異,是由於層狀複合結構之間存在內建電場,能夠降低激發電子與電洞recombination的機率,讓實際參與光解水反應的載子數量有效增加;另外,利用結構與性質介於SrTiO3與AgNbO3之間的(SrTiO3)0.5(AgNbO3)0.5固溶體薄膜作為匹配層,以匹配SrTiO3與AgNbO3形成界面品質更佳之層狀複合結構,其光電流表現又較SrTiO3/AgNbO3提升了一倍以上。
光電極的製備上,以溶膠-凝膠法製備SrTiO3、AgNbO3及其固溶體(SrTiO3)x(AgNbO3)1-x薄膜,所選用的基材為具備導電性與高透光度的ITO玻璃,及高化學穩定性且導電性極優的白金電極。ITO玻璃高透光度的特性能夠增加光電極在應用面與實驗設計面的廣度,此為本研究首選之基材。由於ITO玻璃不耐高溫,本研究成功利用PLT晶種層及高分子PVP360之添加,讓SrTiO3、AgNbO3及SrTiO3/AgNbO3薄膜得以於低溫下製備在ITO玻璃之上。利用溶膠-凝膠法製備(SrTiO3)x(AgNbO3)1-x薄膜為本研究首創,目的是為了調查其與SrTiO3/AgNbO3之間的匹配關係對於光電流性質的影響。以(SrTiO3)0.5(AgNbO3)0.5薄膜作為SrTiO3/AgNbO3匹配層之層狀複合結構,需在高溫下才能夠成相,故以可耐高溫之白金電極作為基材。 In this study, we discuss the application of heterogeneous photocatalyst in photoelectrochemical cell. Two kinds of perovskite oxide thin films, SrTiO3 and AgNbO3, and their solid solution, (SrTiO3)x(AgNbO3)1-x were chosen as sample photoelectrode materials to study the effect of “heterojunction” on their photocurrent responses. It is found that the photocurrent responses of SrTiO3/AgNbO3 layered structures were higher than both the SrTiO3 and AgNbO3 thin films due to the help of “build-in electrical field” which could accelerate the separation of photoinduced e--h+ pairs and reduce the recombination effect. Furthermore, (SrTiO3)0.5(AgNbO3)0.5 thin film was used as a intermediate matching layer to improve the interface quality of SrTiO3/AgNbO3 layered structure. The photocurrent response was further improved by such approach. Sol-gel process was used to fabricate SrTiO3, AgNbO3 and (SrTiO3)x(AgNbO3)1-x thin films on ITO-coated glass or platinum-coated silicon wafer substrates. ITO-coated glass was chosen because of its high transparency, which can offer a wide range of applications. The shortcoming of ITO-coated glass is that it cannot endure temperature processing above 500 °C. In the study, (Pb0.86La0.14)TiO3 seeding layer and PVP modified sol-gel process were used to fabricate SrTiO3 and AgNbO3 thins films and their layered structures on ITO-coated glass substrates at 500 °C. Furthermore, the method of preparing (SrTiO3)x(AgNbO3)1-x thin films by sol-gel process is reported for the first time. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/65042 |
全文授權: | 有償授權 |
顯示於系所單位: | 材料科學與工程學系 |
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