隨著科技持續發展，生活周遭有相當可觀的熱能由民生用品裝置中逸散至環境，例如各式電子、通訊、照明與醫療檢測等等。而熱電材料為一種可以將熱能直接轉換成電能的環境友善性材料，然而目前熱電材料的轉換效率仍低落，再加上既有的傳統熱電材料昂貴且適合操作在擁有極大溫度差的環境下，因此，本研究主要針對在低溫環境下 ( <150℃ )，以酸處理多壁奈米碳管和導電高分子PEDOT:PSS組成的奈米複合結構薄膜為本體，利用極性溶劑DMSO進行不同浸泡時間的後處理，並探討其熱電性質的表現，建立改質後之薄膜的最佳化參數。透過DMSO浸置法後處理，可將熱電薄膜的席貝克係數和導電率分別大幅提升至117.4 μV/ K以及2355.5 S/cm，使最佳化功率因子達到3246.5 μW/mK2，相較於未經浸泡之薄膜的功率因子提升將近10倍，並預計最佳化之薄膜ZT值將可達0.18以上。另外，在實際輸出功率的探討上，在溫差為60 K下，經最佳化浸置法後處理後之熱電薄膜其功率輸出可達107.98 nW，作為日後發展熱電元件的依據。相對於近五年的相關熱電薄膜之處理技術上，本研究在功率因子上由已知文獻最大值之469 μW/mK2提升到3246.5 μW/mK2，優勢在於使用複合結構薄膜，並透過酸處理奈米碳管強化和PEDOT:PSS間的交互作用，亦利用極性溶劑後處理大幅移除絕緣性區域和改變PEDOT:PSS結構，增強複合結構所產生的效應。
在機制探討上，藉由XPS說明PEDOT:PSS化學組成含量比例的變化以及奈米碳管和PEDOT之間的鍵結情形；並透過Raman光譜分析了解PEDOT:PSS構型改變和奈米碳管晶格缺陷減少；亦利用XRD針對層狀堆疊之PEDOT的晶面間距變化和晶體結構對熱電性質的影響進行探討；以及藉著AFM觀察奈米碳管隨後處理所發生的排列情形，最終可證明PEDOT:PSS和奈米碳管之間的協同作用，使薄膜展現優越熱電性質。而未來將持續在可撓式熱電元件技術於醫療檢測與自供電裝置的應用上持續發展。

Thermoelectric materials can convert thermal energy into electricity directly. In this study, we focused on low temperature heat ( <150 ℃ ) and introduced EG-treated PEDOT:PSS blended with functionalized MWCNTs to form the nanocomposites, which would be immersed in polar organic solvent, DMSO under various durations as the post treatment. The mechanism of MWCNTs / PEDOT:PSS nanocomposites is discussed through detailed investigations including morphological, chemical-structure, surface-state band-structure and topographical characterizations. Examinations of conformational changes of involved polymer layer and interaction between PEDOT and MWCNTs are discussed by XPS and Raman analysis. D-spacing difference of PEDOT layer structure and morphology rearrangement of MWCNTs are analyzed by XRD and AFM investigations. The mechanism are carried out to deeply explain the synergetic enhancement in thermoelectric properties of low-temperature thermoelectric films via interaction between functionalized MWCNTs and PEDOT:PSS through DMSO immersion, which is also believed to create nanoscale junction that can filter low energy carriers. After immersing in DMSO, the Seebeck coefficient and the electrical conductivity of treated MWCNTs / PEDOT:PSS can be elevated up to 117.4 μV/K and 2355.5 S/cm respectively. Then, the power factor ( S2σ ) can be significantly increased to 3246.5 μW/mK2. It is expected that the ZT value of the optimized film could reach more than 0.18. Moreover, we also obtain the maximum output power achieved at 107.98 nW at ∆T=60 K. In the future, we will continue to develop the low-temperature and flexible thermoelectric application such as medical testing and wearable self-powered devices.

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