設計不同形貌二氧化鈦光陽極結構於染料敏化太陽能電池之應用

Abstract

本論文介紹兩種不同形貌之二氧化鈦光陽極材料組成雙層或多層結構以進一步提升染料敏化太陽能電池之光電轉換效率。第一種形貌為TiO2奈米棒根據其不同的成長機制可分為三類:(1).一般奈米棒(NR)；(2).大尺寸奈米棒(LNR)；(3).鎖鏈狀奈米棒(CNR)。經過元件動力學分析發現，在電子傳遞能力上是CNR > NR > LNR，但NR於多層結構上的元件效能卻是最好的，另外LNR則因結晶性太差使得整體元件效率不如NR，將CNR混摻NP目的是為了在增加染料吸附量，再搭配多層結構後以Z907為染料之元件光電轉換效率達9.8%。第二種二氧化鈦光陽極形貌為正八面體(HD)，依其尺寸大小分為四類(1).HD1(30 nm–50 nm)； (2).HD1.5(50 nm–100 nm)； (3).HD2(100 nm–150 nm)； (4).HD3(150 nm – 200 nm)；經由元件動力學分析發現此單晶正八面體光陽極材料之VOC比其他同尺寸不同形貌之光陽極還高，且具有良好之電子傳遞能力。結合不同尺寸HD之多層結構光陽極但因JSC不佳而使元件效能比NR多層結構的元件效能差，因此我們將HD1.5與HD2兩種尺寸混摻NP去做多層結構的組合，發現可以有效提升JSC使以Z907為染料之元件光電轉換效率達到10.07%，另外也發現即使用HD1來做雙層光陽極結構其光電轉換效率也同樣達10.09%，這個結果比目前文獻上所報導的元件效能都優異，是目前Z907元件的世界紀錄。

In this thesis , we introduce two different morphologies of titanium dioxide and their application in DSSC using bilayer or multilayer(ML) configurations.The first topic is of TiO2 nanorods and they are devided into three categories:(1). general nanorod (NR)；(2).large size nanorod (LNR)；(3). chain-like nanorod (CNR). After kinetics analysis of devices we found that the electron transport ability has the trend CNR > NR > LNR. We found that NR-based devices with ML configuration had the best performance.The LNR had poor crystallinity so that the device performance was poor. Therefore we used the composites of nanoparticles and CNR as photoanodes and we found that the composite films to improve the amounts of dye loading and to reduce charge recombination.The best performance of the CNR/NP devices using Z907 dye attained . The second topic is octahedron-like TiO2 and they are divided into four categories according to their size: (1).HD1(30 nm - 50 nm)；(2).HD1.5(50 nm – 100nm)；(3).HD2(100 nm – 150nm)；(4).HD3 (150 nm – 200 nm). We fabricated HD devices with ML configurations to gone the photovoltaic performance reaching 10.07%. The same result was also obtained with a HD1 bi-layer configuration which becomes a new world record for Z907-based solar cell.