導電高分子複合薄膜之製備與其在染料敏化太陽能電池 與超級電容器之應用

Preparation of Conductive Polymer Composite Films for Dye-Sensitized Solar Cells and Supercapacitors

陳偉婷(Wei-Ting Chen)

指導教授 ： 何國川

國立臺灣大學/工學院/高分子科學與工程學研究所/碩士(2018年)

https://doi.org/10.6342/NTU201801702

摘要

本論文旨在討論導電高分子複合材料於兩能源領域(染料敏化太陽能電池及超級電容器)之應用，分別透過電聚合法(electro-polymerizarion)及氧化聚合法(oxidation-polymerization)進行導電高分子聚合與複合材料製備。依照不同的材料及應用該論文被分成兩部分：單向維度陣列型sulfonated poly(thiophene-3-[2-(2-methoxyethoxy)ethoxy]-2,5-diyl)/poly(hydroxymethyl 3,4-ethylenedioxythiophene)(S-P3MEET/PEDOT-MeOH)導電高分子複合材料在染料敏化太陽能電池對電極應用(第三章)，以及聚苯胺polyaniline與金屬有機骨架(Metal-Organic Framework)之複合材料於超級電容器之應用(第四章)。
在第三章中，S-P3MEET導電高分子雖然對三碘化物離子與碘離子之間的反應有極好的催化活性，然而平坦的奈米形貌無法提供足夠的催化點，因此在AM 1.5G的光強度下，只能提供5.54%的光電轉換效率，然而我們引入了單維度陣列型PEDOT-MeOH之管柱結構提供足夠的催化面積及單向電子傳遞通道，透過改進其平坦表面形貌之缺點，將S-P3MEET導電高分子之催化優勢顯現出來，根據旋轉電極之實驗結果，證實S-P3MEET展現較佳的電催化常數而PEDOT-MeOH之管柱結構擁有較大的比表面積數值，因此透過互補型的複合材料設計，能同時利用兩種高分子之特點而彌補單一材料不足之處。在此章節中，藉由調整 S-P3MEET在PEDOT-MeOH管柱上覆蓋的含量，找出最適化之複合參數，其中，5-S-P3MEET/PMT之電極能提供較佳的光電轉換效率(9.09% )，比起白金對電極的染敏電池(光電轉換效率: 8.88%)，有著更加卓越的表現。
在第四章中，為了克服金屬有機骨架導電性不佳之缺點而引入了導電共聚高分子poly(3-aminobenzenesulfonic acid)/polyaniline (PABS/PANI)網絡作為橋梁，增加其導電性及提供晶體之間的電子轉移通道，並且根據質子跳遷理論(proton-hopping)，PABS之磺酸取代基(sulfonate group)能有效促進質子在多孔性材料之孔道間的移動，進而提升電容表現。此薄膜經過電化學實驗結果顯示，其可在1 A g-1 的充放電電流密度之下達到510.4 F g-1的比電容值，此數值與純金屬有機骨架及未具有磺酸取代基之導電高分子網路與純金屬有機骨架複合材料相比有明顯提升。除了擁有優秀的比電容值，其長期使用穩定度也達到一定標準，根據實驗數據，在6,000圈的充放電循環後，此複合材料薄膜仍可維持89 %的初始比電容值，相較於共聚高分子(PABS/PANI)在6000圈的充放電循環後只剩下63%的初始比電容值，其長期穩定性有明顯地提升，證明金屬有機骨架的確也扮演了穩定結構的角色。

關鍵字

導電高分子 ； 聚二氧乙基噻吩 ； 染料敏化太陽能電池 ； 金屬有機骨架 ； 聚苯胺及其衍生物 ； 超級電容器

並列摘要

This thesis mainly aimed to develop the conductive polymer composite material utilized in the two energy fields, namely, dye-sensitized solar cells (Chapter 3) and supercapacitor (Chapter 4). The conductive polymer composite materials were prepared by electro-polymerization and oxidation-polymerization in Chapter 3 and Chapter 4, respectively. The overview of these two applications will be displayed in introduction and literatures review (Chapter 1). Moreover, the experimental detail (Chapter 2) includes the chemical regent, material characterization and the principle of electrochemical analysis.
In Chapter 3, electro-polymerized PEDOT-MeOH tube-array (PMT) was utilized as a bottom-up template, which provides unidirectional electron transfer channel and high active surface area for easy-fabricated sulfonated poly(thiophene-3-[2-(2-methoxyethoxy) ethoxy]-2,5-diyl) (S-P3MEET) serving the better electro-catalytic outer layer. Polymer composite material with the synergy effects from two different polymers obtains the better performance owing to compensate the individual shortcomings. The dye-sensitized solar cells (DSSC) with S-P3MEET/PMT composite film as counter electrode (CE) has exhibited a high power conversion efficiency (η) of 9.09% at AM 1.5 G light illumination, while the DSSC with a platinum CE has shown an η of only 8.80%. The catalytic abilities of the electrodes were characterized by cyclic voltammetry (CV), Tafel polarization plots, electrochemical impedance spectroscopy (EIS), and data from rotating disk electrode (RDE). Moreover, incident photon-to-electron conversion efficiency (IPCE) spectra were used to substantiate the photovoltaic performances. By this composite approach, the combination of various structures and conductive polymer can be considered for improving electro-catalytic material.
In Chapter 4, metal-organic frameworks (MOFs) which offer high surface area and regular porosity can be recognized as the potential material for supercapacitor application. In order to solve the critical weakness of poor conductivity deteriorating the capacitance and rate performance in most MOFs, the conductive network with enhanced ionic-conductivity has been established. The introduction of sulfonated group provided by poly(3-aminobenzenesulfonic acid) (PABS) not only increased the proton-conductivity on the basis of proton-hopping effect but also improved the interfacial hydrophilic properties for facile ion and charge transportation. By interconnecting the insulating MOF-525 cubic particles with poly 3-aminobenzenesulfonic acid (PABS) and polyaniline (PANI) copolymers, the composite material of PABS/PANI/MOF-525 showed the extraordinary capacitance of 510.6 F g-1 at 1 A g-1 in 1.0 M H2SO4 aqueous solution compared to PANI/MOF-525 (336.5 F g-1). Moreover, the long-term stability was also examined under a high capacity rate of 15 A g-1. PABS/PANI/MOF-525 composite film remained 89% of its original capacitance after 6,000 cycles. Accordingly, the relatively stable performance indicated the enhanced flexibility and mechanical properties supported by the MOF-525 crystalline. This proposed method cast light on a concept for MOF-based material in electrochemical application.

並列關鍵字

Conductive polymer ； Poly(3,4-ethylenedioxythiophene) ； Dye-sensitized solar cells ； Metal-organic framework ； Polyaniline and its derivatives ； Supercapacitor

參考文獻

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