以電泳法製備二氧化鈦/金奈米複合膜應用於染料敏化太陽能電池之研究

Applications of hybrid nanocrystalline TiO2/Au films prepared by electrophoretic deposition on dye-sensitized solar cell

邱琬琪(Wan-Chi Chiu)

指導教授 ： 閔庭輝

國立虎尾科技大學/電機資訊學院/光電與材料科技研究所/碩士(2010年)

摘要

本研究利用兩種不同方法製備二氧化鈦/金(TiO2/Au)複合層工作電極，應用在染料敏化太陽能電池上面。利用檸檬酸還原法製備出的金奈米粒子與二氧化鈦均勻混合後，再利用電泳沉積法製備出二氧化鈦/金複合層(EPD-TiO2/Au)。另一種方法，則是利用光還原法還原並自組裝成長出金奈米粒子在二氧化鈦薄膜表面，製備出二氧化鈦/金複合層(Light-TiO2/Au)。加入N3染料及電解液，封裝成染料敏化太陽能電池(DSSC)，透過I-V特性量測，觀察其光電轉換效率。
利用檸檬酸還原法製備出的圓球形金奈米粒子吸收光波長為520 nm左右，平均粒徑約為21 nm。由FE-SEM及EDS觀察二氧化鈦/金複合層薄膜表面形態及金奈米粒子分佈及含量。由XRD分析出二氧化鈦銳鈦鑛相及金紅石相主要峰值在(101)及(110)面繞射峰強度為最強，金奈米粒子以(111)面繞射峰強度為最強，符合金之FCC繞射平面。隨著金奈米粒子的增加，主要峰值的強度也逐漸增加。本實驗所製備的傳統二氧化鈦染料敏化太陽能電池(DSSC)轉換效率為2.877 %，而電泳沉積二氧化鈦/金複合層轉換效率為3.203 %。添加金奈米粒子在二氧化鈦薄膜上，因為蕭特機能障存在，可以有效地減少電荷在染料（或電解質）中的再結合率。而金奈米粒子的表面電漿共振特性，可以有效的增強染料激發光電子產生，增加導電率，藉此提升DSSC轉換效率。

關鍵字

金奈米粒子 ； 電泳沉積法 ； 染料敏化太陽能電池

並列摘要

In this study, preparation of two different methods TiO2/Au hybrid films and working on the electrode of dye-sensitized solar cell (DSSC). TiO2 thin films were prepared were by electrophoretic deposition (EPD). We used a citrate reduction method and photochemical deposition method to prepared gold nanoparticles on TiO2 thin film, respectively.
Gold nanoparticles investigated by the measurements of ultraviolet-visible absorption spectra (UV-Vis) of the peaks observed at 520 nm arise from the surface plasmon resonance (SPR) in the spherical gold nanoparticles. The shape of gold nanoparticles observed by transmission electron microscopy (TEM) was spherical and the average diameter was 21 nm. The XRD pattern shows the TiO2/Au hybrid films, which primarily peaks of anatase (101), rutile (110) and Au (111). The peaks are corresponding to the FCC metallic gold diffraction. The intensity of peak were increases with increase in the size of gold nanoparticles. The surface plasma resonance of the gold nanoparticles, can efficient enhancement of photoexcitation of electrons in the dye molecules.
Most importantly, this study shows that the energy conversion efficiency of DSSC with the EPD-TiO2/Au hybrid film is 3.203 %, and is guite higher than that TiO2 thin film, which is 2.877 %.
From the results of I-V characteristics, the gold nanoparticles added in TiO2 thin films can effectively reduce the recombination of charges in the dye (or electrolyte). The presence of the Schottky barrier can increase the conductivity and the conversion efficiency of DSSC. However, much more gold nanoparticles added in TiO2 thin films will reduce the absorption of the dye resulting in the reduction of conversion efficiency of DSSC.

並列關鍵字

gold nanoparticles ； electrophoretic deposition ； dye-sensitized solar cell

參考文獻

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