以水熱法製備氧化鋅奈米結構電極應用於染敏太陽能電池之研究

A Nanostructural Zinc Oxide Electrode Prepared by a Hydrothermal Method for Dye-Sensitized Solar-Cell Application

在本實驗中，我們先使用水熱法在銦錫氧化物（indium-tin-oxide, ITO）玻璃基板上成長氧化鋅（ZnO）奈米柱。成長過程使用不同莫爾濃度的硝酸鋅六水合物（zinc nitrate hexahydrate, Zn(NO3)2•6H2O）及六亞甲基四胺（hexamethylenetetramine, C6H12N4）混合溶液以得到ZnO 奈米柱。此外，我們也把成長完成的ZnO 奈米柱浸泡在染料中製作成染敏太陽能電池（dye-sensitized solar cell, DSSC）元件。我們利用掃描式電子顯微鏡（scanning electron microscopy, SEM）、能量散佈能譜（energy dispersive spectroscopy, EDS）及X 光繞射儀（x-ray diffraction, XRD）等量測分析對不同莫爾濃度混合溶液所成長的ZnO 奈米柱的表面型態、化學成分與晶格結構，並對使用不同莫爾濃度混合溶液所成長的ZnO 奈米柱作為工作電極所製作而成的DSSC 進行I-V 電性及照光特性分析。由實驗結果得知，0.2M 的Zn(NO3)2•6H2O+C6H12N4所成長的ZnO 奈米柱可以增加工作電極的緻密度及均勻性，其幾何形狀、表面分佈及微結構等特性可以增加染料的吸附數量， 並且有利於載子的傳輸。因此， 使用0.2M 的Zn(NO3)2•6H2O+C6H12N4 所成長的ZnO 奈米柱來製作的DSSC 可得到改善的短路電流、填充因子及轉換效率。 In this study, zinc oxide (ZnO) nanorods were synthesized on indium-tin-oxide (ITO) glass substrates by a hydrothermal process using various molar concentrations of Zn(NO3)2•6H2O+C6H12N4. Subsequently, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and x-ray diffraction (XRD) were used to obtain the surface morphology, chemical composition, and crystallographic structure of the nanorods. These nanorods were then submerged in a dye solution and used as the working electrode for a dye-sensitized solar cell (DSSC). The I-V and optoelectronic characteristics of DSSCs using the nanorods prepared by various concentrations of Zn(NO3)2•6H2O+C6H12N4 as the electrodes were measured to obtain their fill factors and conversion efficiency. The experimental results revealed that the ZnO film prepared by 0.2M of this compound exhibits a uniform distribution of dense nanorods whose shape and microstructure are beneficial to dye adsorption and carrier transport. Therefore, the DSSC fabricated with the nanorods prepared by the 0.2M process has an improved short-circuit current, fill factor, and conversion efficiency.