以高壓原位合成法製備二氧化鈦/聚己烷噻吩高分子 奈米混成系統:製程研究及太陽能電池應用

Abstract

本實驗藉由聚己烷噻吩導電高分子作為結構模板，製作混成二氧化鈦之有機/無機奈米混成系統。本研究揭露一簡易的原位合成方式，利用鈦離子(Ti4+)與高分子之噻吩官能基間的分子間作用力(intermolecular interaction)使二氧化鈦前趨物(Titanium tetraisopropoxide, Ti4+(OiPr)44-, TTIP)與高分子進行嵌合而均勻分散形成P3HT/Ti4+混成系統，為了避免二氧化鈦聚集而無法成為奈米等級顆粒，透過化學氣相沉積的概念，先將P3HT/Ti4+溶液成膜使之固化為P3HT/Ti4+薄膜再利用含水之高壓蒸氣使之進行原位融膠-凝膠反應而形成奈米級非晶質二氧化鈦，其再於高壓下進行結晶而形成奈米級結晶相二樣化鈦，成功製作P3HT/TiO2之混成系統。 透過GIWAXS光譜儀確認二氧化鈦之結晶型態中，發現高壓蒸氣的種類、溫度、與TTIP的反應時間會影響P3HT的結晶、二氧化鈦的結晶顆粒大小和結晶型態的轉變甚至是自組裝行為，藉由了解各種參數的影響可控制二氧化鈦之結晶。透過二維GIWAXS的結果提出一種新概念:在二氧化鈦結晶過程進行第二次自組裝行為，此行為與金紅石(rutile)的低溫形成機制有相同概念。並透過XPS的檢測證實Ti4+與噻吩官能基之間的嵌合反應，利用TEM了解此混成系統的型態為一句有良好方向性的奈米線。最後透過UV-vis和PL的分析知道此混成系統擁有良好的光電性質可應用於太陽能電池。

In this study, we used P3HT as a template in-situ synthesizing titanium dioxide to manufacture an organic/inorganic nanohybrid system. This study reveals a simple in-situ method to manufacture a P3HT/TiO2 hybrid system. First, we made a P3HT/Ti4+ hybrid system by the formation of complextion via the intermolecular interaction between thiophene and titanium ions (Ti4+). To preserve TiO2 crystallizing in nanoscale, via the concept of chemical vapor deposition, we first let the solvent of P3HT/Ti4+ hybrid solution to evaporate to form a P3HT/Ti4+ hybrid thin film. Following, we used high pressure vapor containing H2O proceeding the in-situ sol-gel process to form a nanoscale amorphous TiO2, and then by the high pressure treatment, amorphous TiO2 crystallized to a nanoscale crystalline TiO2. We manufactured a P3HT/TiO2 nanohybrid system successfully. In the GIWAXS measurement, we found that many factors, containing the kinds of vapor conditions, reaction temperature and reaction time, affected the P3HT crystal structure, TiO2 crystal size, the transformation of TiO2 crystal structure and even the self-assembly. We can control the crystalline of TiO2 via finding out the influence of these parameters. In the 2D GIWAXS measurement, we provide a new concept: the hybrid system will proceed second self-assembly in the crystallization process. This attributed to the same concept with the mechanism of rutile formation in low temperature. In XPS measurement, we confirmed our assumption of intermolecular interaction between thiophene and titanium ions. The TEM profile reveals that the morphology of our hybrid system has good orientation to be a nanowire. Finally, via the UV-vis and PL analysis, we know the optical properties are good to be used in solar cells application.