摻雜鹽酸聚苯胺薄膜之導電機制研究

Electrical transport of HCl-doped polyaniline thin film

江曉斌(Shiau-Bin Jiang)

指導教授 ： 鐘元良

中原大學/理學院/應用物理研究所/碩士(2009年)

https://doi.org/10.6840/CYCU.2009.00880

摘要

本論文主要是探討導電高分子-聚苯胺(Polyaniline)薄膜在低溫下的導電機制，我們量測隨不同溫度變化下的電阻率，再加以分析來去探討電子的導電機制。
聚苯胺是利用電化學聚合的方式來備製，電化學聚合主要的優點在於它可以聚合出較完整的分子鏈，而且分子鏈也以交錯的方式排列而成，也可利用電化學參數來控制薄膜的厚度。因為分子鏈之間的交錯排列(由 SEM 觀察)，所以在低溫下電子傳輸機制令我們感到興趣。在實驗方面，我們針對不同厚度的聚苯胺薄膜進行低溫下的量測，當薄膜厚度降低時，使得原本鏈與鏈之間的排序變為鬆散。而電子在鏈上主要傳輸模式分為兩種：一. 電子在主鏈上的傳輸 二. 鏈與鏈之間的傳輸，因為結構上變為鬆散，使得鏈與鏈之間距離變得更遠，而讓電子主要是以在主鏈上傳輸的一維模式，所以必須考慮到電子-電子交互作用力。在實驗數據上，我們主要以跳躍模型來探討電子如何在高分子鏈上傳輸，由實驗得到的電阻率與溫度的關係，分別代入 Mott VRH 與 ES VRH 模型中，來分析當聚苯胺結構逐漸變為鬆散時，其導電機制是否有所變化。
最後結果，我們看到藉由厚度(鬆散度)影響電子在分子鏈之間傳輸的機制，當厚度逐漸下降時，會看到的原本傳輸行為由 Mott VRH 轉移至 ES VRH 的現象，因為在這種鬆散結構下，使得電子是在主鏈上進行準一維的跳躍，所以電子-電子交互作用力是更加的顯著。

關鍵字

聚苯胺 ； 變程跳躍 ； 導電高分子 ； 電化學

並列摘要

In this thesis we will discuss electric transport mechanisms in conducting polyaniline thin film at low temperature. We have measured electronic resistivity of polyaniline thin film in different temperature for discussing electric transport mechanisms.
The polyaniline was polymerized by electrochemistry method and this is an excellent method for completely polymerizing the chain of molecule. The thickness of polyaniline was controlled by the parameters of polymerization. Electric transport mechanisms of interchain are very attractive. In experiment, we measure electric property in different thickness of polyaniline film. The structure of interchain will transform into looser when polyaniline become thinner. The mode of electronic transport can be two types on the chain： The first of transport is on the chain. The second of transport is on interchain. Because structure becomes thinner, this implies that the carriers transport of the polyanilin are a quasi-one-dimensional variable-range-hopping process and must consider the effects of electron-electron interactions. We will focus to discuss hopping models how do the electron transport on the polymer chain. A systematic change on the molecular structures was conducted to understand electronic transport mechanisms transfer. At the result, we demonstrate that the thickness of polyaniline can influence transport mechanisms. Electronic transport mechanisms transfer from Mott VRH to ES VRH when film become thinner, and because of this condition, it causes the electron to hop by quasi-one-dimensional type on the chain, the effects of electron-electron interactions must be considered.

並列關鍵字

variable-range-hopping ； electrochemistry ； polyaniline

參考文獻

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