釐米尺度之單一方向排列的有機小分子與高分子薄膜：製膜方法與掃瞄式探針顯微鏡之研究

Long-Range Uniaxial Alignment of Polyaromatics and Polybisnorbornenes: Preparation Methodology and Characterization by Scanning Probe Microscopy

李昇隆(Shern-Long Lee)

指導教授 ： 陳俊顯

國立臺灣大學/理學院/化學研究所/博士(2009年)

https://doi.org/10.6342/NTU.2009.02710

摘要

本論文研究的主要成果為發展快速、簡易的薄膜製備技術以因應分子電子元件(molecular electronics)領域對於製膜技術之需求。我們發現紙張的毛細現象所引發的流體運動，可控制多苯環有機小分子(如3,6,11,14-tetradodecyloxydibenzo[g,p]chrysene ((C12O)4DBC1與coronene等)於基材表面的排列位向，這個方法可歸納為流體在液固界面的剪力導致物質排列的方式。實驗結果證實此製膜方法可使數種原本平躺於基材表面的分子站立，並形成規則的線狀排列，規則的分子排列距離長達7 mm。因電子可再立起且以線狀排列的分子薄膜內自由移動，此種製膜技術也可使高分子(如double stranded oligobisnorbornene)沿著同一個方向進行接合，在數百奈米的接合中只有0.5%的缺陷被觀察到。
掃描式穿隧顯微鏡 (scanning tunneling microscopy，STM)與原子力顯微鏡(atomic force microscopy，AFM)是本研究工作的實驗方法，用來分析吸附於固體表面的分子在受到流體側向流動的剪力後所造成的吸附位向與排列方向的變化等。本論文也探討經由剪力誘導所製備的薄膜之物化特性，包含量測薄膜的偏光性以及利用掃描式穿隧能譜 (scanning tunneling spectroscopy，STS)探討不同吸附位向與排列方式的分子之能階變化等。

關鍵字

掃描探針顯微術 ； 配向 ； 分子自組裝

並列摘要

To develop new methods for the preparation of thin-films for molecular electronics application is the major goal of this dissertation. We report the assembly of polyaromatic monolayers that exhibit predominantly one single-domain up to 7 mm by planar Couette-like flow whose anisotropic shear induces an edge-on orientation for 3,6,11,14-tetradodecyloxydibenzo[g,p]chrysene ((C12O)4DBC)1 and coronene which would otherwise adapt the face-on arrangement on graphite surface. Due to electrons can move freely through the packed molecules, the thin-film hence can be considered as a good pathway for electron transfer. In addition, with a shear treatment for dropcast films, a unidirectionally ordered domain of double Stranded Oligobisnorbornene with a defect density less than 0.5% can be prepared. Simulation results by molecular dynamics suggest that there may be multiple interactions such as pi-pi stacking and dipolar attractions taking place between the termini of the oligomers.
Scanning tunneling microscopy (STM) and atomic force microscopy (AFM) are major approaches in this dissertation used to analyze molecular orientations before and after being subjected to shear treatments. We also investigate optical properties of the prepared thin-films and perform STS measurements for the discussion of molecular adsorptions as well as the variety of energetic levels of molecules.

並列關鍵字

Scanning Probe Microscopy ； alignment ； molecular self-assembly

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