微等离子法制备原位生长TiO_2薄膜电极研究

Research on TiO_2 thin film electrode grown in situ prepared by micro plasma method

采用微等离子体氧化法制备用于染料敏化太阳能电池的原位生长TiO2薄膜电极。筛选适合制备较高光电性能原位生长TiO2薄膜电极的电解液,利用扫描电镜(SEM)、X射线衍射(XRD)和交流阻抗谱(EIS)考察电解液类型对所得TiO2薄膜电极的表面形貌、晶相组成和内部阻抗的影响,并利用X射线光电子能谱(XPS)和红外吸收(IR)研究染料敏化剂与TiO2薄膜表面的相互作用。结果表明,以(NH4)2SO4为电解液制备TiO2薄膜的光电性能高于硫酸体系所得TiO2薄膜的光电性能,短路电流、开路电压和光电转换效率分别为49μA/cm2,652mV和0.095%。薄膜主要由大量的金红石和少量的锐钛矿和钛组成,并且以(NH4)2SO4为电解液制备的薄膜中,TiO2含量较高。膜层较厚,约为7.5μm。薄膜的内部阻抗相对较小,有利于染料敏化太阳能电池光电性能的提高。所得TiO2薄膜电极的光电性能较高;cis-Ru(dcbpy)2(NCS)2染料可以吸附在微等离子氧化法制备的TiO2薄膜表面。染料cis-Ru(dcbpy)2(NCS)2敏化后的TiO2薄膜XPS谱中出现了O=C-O基团中的C1s吸收峰,说明染料可以吸附在微等离子氧化法制备的TiO2薄膜表面。在红外光谱中,在1 737nm处出现了一个吸收峰,应为酯键羰基振动所引起的,由此可以推断染料与TiO2表面应以类酯键形式结合。

TiO2 thin film electrode grown in situ for dye sensitized solar cells was prepared using the mi cro plasma oxidation method. The electrolyte was filtrated according to the photoelectric properties of the TiOe thin film electrode. The effects of electrolyte on the surface morphology,phase composition and internal impedance are investigated by scan electron microscopy （SEM）, X-ray diffraction （XRD） and electrochemical impedance spectroscopy （EIS）. The interaction between dye and the surface of TiOe thin film is studied by X-ray photoelectron spectroscopy （XPS） ans infrared absorption （IR）. The results show that the TiO2 film electrode has higher photoelectric performance using （NH4）2SO4 as electrolyte than that using other electrolytes. The open circuit voltage, short circuit current and photoelectric efficiency are 149μA/cm2 , 652 mV and 0. 095 %, respectively. The prepared TiO2 films consist of a large amount of rutile and a small amount of anatase and titanium,and the content of TiO2 prepared with （NH4）2 SO4 is higher than that prepared with H2 SO4. Also, the membrane layer is thicker, about 7.5 tam. The inter nal impedance of the TiO2 film is relatively small. The XPS of the TiO2 film after being sensitized by the dye cis- Ru（dcbpy） 2 （NCS） 2 presents the cis peak of the O= C-O group, which indicates that the dye can be adsorbed on the TiO2 film surface. The infrared spectrum has an absorption peak at 1737 nm induced by the vibration of carbonyl in ester bond. It can be inferred that the link between dye and TiO2 surface is realized by the analogous ester bond.