電沉積電位及時間對Ag-In-Se/TiO2薄膜性質及光電轉換效率的影響

Effects of electrodeposited potential and time on the properties and photovoltaic efficiencies of Ag-In-Se/TiO2 filems

許維中(Wei-Chung Hsu)

指導教授 ： 陳龍泉

崑山科技大學/工程學院/材料工程研究所/碩士(2011年)

摘要

本論文利用10mM Ag2SO4、60mM In2(SO4)3、20mM SeO2的硫酸電鍍液為起始原料，以電沉積方式於ITO-TiO2上成長Ag-In-Se薄膜，討論其物理性質並應用於半導體敏化太陽能電池之研究。XRD的分析結果指出，在沉積電位-1.0至-1.6V及電沉積時間10至45分鐘的範圍內所製備的樣品，經250℃的真空煅燒後，主要的結晶結構均為Ag2Se，但ESCA及EDX分析均指出樣品含有銦的成分，因此推測尚有其他非結晶或微量成分存在。SEM分析指出二氧化鈦有助於分散電沉積Ag-In-Se，形成多孔性結構、降低Ag-In-Se粒徑及形成Ag-In-Se/TiO2的均勻界面結構。經由Uv-vis-nir光譜分析及Tauc plot ((αhν)2 against (hν))，可得Ag-In-Se薄膜的直接能隙約為1.2eV。藉由此條件製備之樣品在分別使用Co2+/Co3+、S/S2-及I-/I3-電解液進行電池轉換效率分別為0.24%、0.31%及0.13%，顯示硫系電解液具有最大的效率，而碘系電解質的效率最差。於Ag-In-Se薄膜外層塗佈ZnS保護層，因為具有降低光電子逆向反應的效率，因此大幅提升光電轉換效率，在S/S2-、Co2+/Co3+及I-/I3-的電解液中效率約增加171、167及369%。

關鍵字

二氧化鈦 ； Ag-In-Se ； 電沉積 ； 鈷系電解液 ； 硫系電解液 ； 敏化太陽能電池 ； 硫化鋅

並列摘要

Electrodeposition of Ag-In-Se thin films on ITO-TiO2 substrates using 10mM Ag2SO4、60mM In2(SO4)3、20mM SeO2 as precursors was carried out. These prepared Ag-In-Se films were characterized and applied for semiconductor-sensitized solar cells. XRD analysis indicated that Ag2Se was the main crystal structure during the ranges of electro-deposited potential and time of -1.0 to -1.4V and 10 to 45 min, respectively. In-contained compounds in amorphous state or in trace quantity occurred in addition to Ag2Se. SEM analysis suggested that titanium dioxide benefited the dispersion of electrodeposited Ag-In-Se, leading to a homogeneous Ag-In-Se/TiO2 heterojunction with porous structure and small particle size. The direct band gap energy of the prepared Ag-In-Se film was estimated to 1.2 eV according to the optical study and Tauc plot of (αhν)2 against (hν). The Ag-In-Se films prepared with applied bias of -1.4V (MSE) and electrodeposited time of 10 min revealed the optimal efficiencies of 0.24, 0.31, and 0.13% using Co2+/Co3+、S/S2-及I-/I3- as electrolytes, respectively. The electrolyte S/S2- showed a higher efficiency than those of Co2+/Co3+and I-/I3-. Applying a layer of ZnS on the surface of Ag-In-Se film significantly increased the photovoltaic efficiency by c.a. 1.71, 1.67, and 3.69 times using S/S2-, Co2+/Co3+, and I-/I3-, respectively, as the electrolytes due to decreased recombination of photogenerated electrons.

並列關鍵字

titanium dioxide ； Ag-In-Se ； electrodeposition ； Co2+/Co3+ electrolyte ； S/S2- electrolyte ； sensitized solar cell ； ZnS

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