染料敏化太陽能電池用導電高分子聚苯胺及聚二氧乙基噻吩陰極催化劑的探討

Applications of PANI and PEDOT as Cathodic Catalysts for Pt-free Dye-Sensitized Solar Cells

陳思蒨(Szu-Chien Chen)

指導教授 ： 吳春桂

國立中央大學/理學院/化學系/碩士(2011年)

摘要

染料敏化太陽能電池 ( DSSC ) 因具有低成本、多彩、質輕、製程簡單、可大面積製作、且可製備成可撓曲式…等優點，具有極高發展潛力而備受到科學家們的重視。DSSC中，對電極(陰極)上的催化劑扮演著催化電解質中I3- / I- 還原反應及傳送電洞至陰極的角色，故材料需具備高催化活性及高導電度的特性。目前，鉑 ( Pt ) 為最廣泛被用來作為DSSC中對電極上催化劑的材料，然而，Pt的價格高，且製作過程中需高溫鍛燒或高真空的蒸鍍製程也增加了大面積製作及應用在可撓式基版的困難度。本實驗主要是利用導電高分子聚苯胺 ( PANI ) 及聚二氧乙基噻吩 ( PEDOT ) 作為染料敏化太陽能電池中陰極催化劑。研究中發現PANI粉末及PEDOT粉末可均勻分散在HFIP ( 1,1,1,3,3,3-Hexafluoro-2-propanol ) 中，不會產生導電高分子的聚集。由導電高分子 / HFIP溶液製備的高分子膜可緊密的附著於FTO電極上；而且HFIP的沸點低 ( 59 °C)，導電高分子溶液在製備成膜的過程中不需加熱，故可減少能源的消耗。以PANI - HFIP為陰極催化劑，搭配本實驗室所合成的CYC-B11染料為光敏劑所組裝成的DSSC元件其光電轉換效率為7.77 % ( Pt：8.83 % )；若使用硫酸摻雜之聚苯胺/ HFIP溶液鍍在FTO上所製備PANI- SO4-HFIP對電極，搭配CYC-B11光敏劑所組裝之電池元件的光電轉換效率可高達8.76 % ( Pt：8.83 % )。另外以 PEDOT 為陰極催化劑，以CYC-B11為光敏劑所組裝的DSSC元件，其光電轉換效率最高可達8.98 % ( Pt：8.74 % )，證實導電高分子陰極催化劑可以由溶液製程製備，達到減低成本的目的。

關鍵字

染料敏化太陽能電池 ； 聚苯胺 ； 聚二氧乙基噻吩 ； 陰極催化劑

並列摘要

Dye-Sensitized Solar Cells (DSSCs) are attractive the third generation thin film solar cells due to their low cost, light weight, colorful, fabricated easily and flexible. Generally, platinum is employed as a catalyst for the cathode in DSSC to catalyze the reduction reaction (I3- to 3I-) of the electrolyte. However, platinum is one of the most expensive materials on the earth. The preparation of Pt counter electrode at high temperature also increases the cost and difficulty in fabricating large-size device. Therefore, extensive studies have been carried out for developing other cheaper materials to replace Pt in DSSC. In this study, we investigated the performance of DSSCs using polyaniline (PANI) or poly(3,4-ethylenedioxythiophene) (PEDOT) as a catalyst on the counter electrode. We found that HFIP (Hexafluoroisopropanol) is a very good solvent for PANI and PEDOT powder. PANI and PEDOT counter electrode with large surface area and good conductivity can be made from PANI/HFIP and PEDOT/HFIP solution simply by spin coating at room pemperature, and the heating process is unnecessary. DSSC uses PANI/ FTO as a counter electrode exhibits an efficiency of 7.77 % with CYC-B11 as a sensitizer ( Pt：8.83 % ). Nevertheless, the efficiency of DSSC used PANI-SO4-HFIP CE (made from the H2SO4-Doped PANI/HFIP solution by spin coating the film on FTO) as counter elctrode achieves the highest efficiency of 8.76 %，which is comparable to that (8.83 %) of Pt-based DSSC under the same fabrication and measurement conditions. Furthermore, dispersing of PEDOT powder in HFIP was also used to prepare PEDOT counter electrode (PEDOT CE) by spin coating. The efficiency of PEDOT CE-based DSSC with CYC-B11 as sensitizer is 8.98 % ( Pt：8.74 % ). The results proved that conjugated polymers are good materials for replacing Pt as a counter electrode catalyst for DSSC.

並列關鍵字

PEDOT ； Cathodic Catalysts ； Dye-Sensitized solar cell ； Polyaniline

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