多孔性氧化鋅薄膜光電極之退火溫度於染料敏化太陽能電池的應用

本研究是利用不同鍛燒溫度(325℃、400℃、475℃)於多孔性氧化鋅薄膜，透過溫度效應觀察材料的變化對染料敏化太陽能電池的光伏特性影響。在實驗的過程中變換多孔性氧化鋅薄膜鍛燒溫度，鍛燒溫度在325℃與400℃溫度下，較低溫度形成的氧化鋅薄膜顆粒較小，因此有足夠表面積提供染料吸附，在光電流及光電轉換效率上比鍛燒溫度475℃好。鍛燒溫度400℃氧化鋅薄膜的晶格尺寸最大，所以有較好的電子傳導能力。從光激發光光譜分析得知400℃條件材料能帶中的氧缺陷較多，可提高陽極導電性，因此在光電轉換效率上優於475℃。利用電化學阻抗分析(Niquest與Bode圖)染料敏化太陽能電池，低溫段鍛燒下之氧化鋅薄膜陽極之電子傳導能力及導帶電子數目亦較好。由外部量子效率量測(IPCE)結果亦證實染料吸附量所激發之電子電流皆高於475℃。此外，透過表面氧電漿處理氧化鋅薄膜可提昇染料附著能力，光電流與光電轉換效率亦微幅提升，但成效有限。

關鍵字

退火溫度鍛燒溫度；光激發光光譜；染料敏化太陽能電池；光伏特性；外部量子效率；氧缺陷

並列摘要

In this study, mesoporous znic oxide (ZnO) film using different annealing temperature (325 ℃, 400 °C, 475 °C) was used as photoanode to observe the photovoltaic characteristics for dye-sensitized solar cell (DSSC) application. Among these annealing temperature conditions, at lower temperature (325 ℃, 400 °C), the particle size was small compared to higher annealing temperature (475 °C). Therefore, the dye amount absorbed on ZnO photoanode was enough to convert photocurrent and obtain high light-electric-convert efficiency (η). The grain size annealed by 400 °C was large by X-ray diffraction (XRD) measurement which results in better electron conductivity. Form the photoluminescence (PL) measurement, the 400 °C annealing sample exhibits high electrical conductivity due to rich oxygen vacancies, thus the efficiency is better than 475 °C annealing sample. The electrochemical impedance spectroscopy (EIS) analysis was used to verify DSSC performance by Niquest and Bode plots. Both electron number on conduction band and electrical conductivity are acceptable at lower annealing temperature conditions. From the IPCE (Incident Photon to Current Efficiency) measurement, the high IPCE result in lower annealing temperature also demonstrates that the amount of dye-absorbed on ZnO photoanode is higher compared to 475 °C. Besides, the ZnO photoanode film was treated by oxygen plasma to observe the dye-absorption. The results exhibits that the photovoltaic characteristics and efficiency are slightly enhanced.

並列關鍵字

Dye-sensitized solar cells ； Photovoltaic ； PL ； oxygen vacancy Annealing Temperature ； IPCE

參考文獻

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[10] M. Grätzel, ” Conversion of sunlight to electric power by nanocrystalline dye-sensitized solar cells”, Journal of Photochemistry and Photobiology A: Chemistry, vol. 164, pp. 3-14, 2004

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多孔性氧化鋅薄膜光電極之退火溫度於染料敏化太陽能電池的應用

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