金奈米粒子形成蕭基式能障應用於多層複合式TiO2染料敏化太陽能電池

Application of Schottky barrier to dye-sensitized solar cells (DSSC) with multilayer thin films of photoelectrode

林修平(Xiu-Ping Lin)

指導教授 ： 張合

國立臺北科技大學/機電學院/製造科技研究所/碩士(2010年)

摘要

文旨在金與二氧化鈦會形成蕭基式能障(Schottky barrier)並應用於染料敏化太陽能電池（Dye-Sensitized Solar Cells）中光電極之薄膜製備技術，因蕭基式能障的存在，電子將無法回到染料分子或電解液中，以此方式將有效地提高電子轉換效率。先將商用二氧化鈦粉體（Degussa P25）置於強鹼溶液中以水熱法（Hydrothermal）製得氧化鈦奈米管（Tnt），將Tnt經550℃煅燒處理得到TntC550顆粒，再做二次水熱法製成半透明溶膠，經烘箱烘烤溫度180度後得到H180顆粒，將H180和TntC550以刮刀法(doctor blade)塗佈成高分子透明薄膜，其中H180為第一層薄膜，TntC550為第二層，都以450℃之燒結處理。第三層再用鹽類還原法(salt reduction)製備金奈米粒子，使用四氯金酸(Hydrogen Tetrachloroautate，HAuCl4)和檸檬酸鈉(Trisodium citrate，C6H5Na3O7)製作出金奈米粒子，金奈米粒子為圓形，粒徑約為27nm，以自主裝法附著成膜，完成染料敏化太陽能電池之光電極製備。染料方面使用化學染料N719，也使用天然染料，以石榴葉片作為本實驗之葉綠素染料，以藍莓作為本實驗之花青素染料，再將將萃取好的葉綠素染料與花青素染料以1：1混合作為雞尾酒染料，比較三種不同天然染料，觀察其光電轉換效率之影響。加入電解質，反電極(Pt)最後形成三明治結構 (Sandwich structure)，封裝完成後之染料敏化太陽能電池將檢測其填充因子(Fill Factor)、光電轉換效率(Solar energy-to-electricity conversion efficiency)及入射光電流效率(Incident photon-to-current conversion efficiency)。經由電流-電壓曲線(Photocurrent-photovoltage curve)之檢測結果顯示，本研究所製備出之染料敏化太陽能電池(DSSCs)使用N719染料，其光電轉換效率達4.96％。

關鍵字

染料敏化太陽能電池 ； 蕭基式能障 ； 金奈米粒子 ； 水熱法 ； 氧化鈦奈米管 ； 天然染料

並列摘要

This study combines Au nanoparticles with TiO2 nanoparticles to form Schottky barrier, and applies it to the photoelectrode thin film of dye-sensitized solar cells (DSSCs). Due to the existence of Schottky barrier in DSSC, electrons are unable to go back to the dye molecules or electrolyte, thus effectively enhancing the electronic conversion efficiency. First, commercial TiO2 powder (Degussa P25) is put in the alkaline solution to prepare for TiO nanotubes (Tnt) by hydrothermal. Tnt are sintered at 550℃ to obtain TntC550 particles and fabricated into translucent sol by two times of hydrothermal and baked in the oven at 180℃ to acquire H180 particles. H180 and TntC550 are spread into transparent polymer film by doctor blade. H180 served as the first layer, and TntC550 – the second both are sintered at 450℃. The third layer adopts hydrogen tetrachloroautate (HAuCl4) and trisodium citrate (C6H5Na3O7) to prepare for Au nanoparticles by salt reduction. Au nanoparticles, round with size around 27nm are adhered to TntC550 to become film by self-assembly to complete the preparation of the photoelectrode of DSSCs. N719 dye and natural dye –pomegranate leaves served as chlorophyll and blueberries as anthocyanin dyes are employed in this study. Extracted chlorophyll and anthocyanin dyes are blended with the proportion of 1: 1 to be cocktail dye and these three different natural dyes are compared to observe its photoelectric conversion efficiency respectively. Electrolyte and counterelectrode (Pt) are added to form the sandwich structure of DSSCs. After being sealed, DSSCs are taken the tests of fill factor, photoelectric conversion efficiency and incident photon-to-current conversion efficiency. Results from the photocurrent-photovoltage curve show that photoelectric conversion efficiency of DSSCs fabricated by using N719 dye in this study can reach 4.96%.

並列關鍵字

Dye-sensitized solar cells (DSSCs) ； Schottky barrier ； Au nanoparties ； TiO nanotubes (Tnt) ； Hydrothermal ； natural dye

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