Sewvandi Galhenage A, Tao Zhuoqi, Kusunose Takafumi, Tanaka Yasuhiro, Nakanishi Shunsuke, Feng Qi
Department of Advanced Materials Science, Faculty of Engineering, Kagawa University , 2217-20 Hayashi-cho, Takamatsu 761-0396, Japan.
ACS Appl Mater Interfaces. 2014 Apr 23;6(8):5818-26. doi: 10.1021/am500666e. Epub 2014 Apr 9.
Back electron transfer from the TiO2 electrode surface to the electrolyte is the main reason behind the low-open circuit potential (Voc) and the low-fill factor (FF) of the dye-sensitized solar cells (DSSCs). Modifications to the TiO2 electrode, fabricated using {010}-faceted TiO2 nanoparticles with six different kinds of silane, are reported to decrease the back electron transfer on the TiO2 surface. The effect of alkyl chain length of hydrocarbon silanes and fluorocarbon silanes on adsorption parameters of surface coverage and adsorption constant, interfacial resistance, and photovoltaic performances were investigated. Adsorption isotherms, impedance analysis, and photovoltaic measurements were used as the investigation techniques. The reduction of back electron transfer depended on the TiO2 surface coverage by silane, alkyl chain length, and the molecular structure of the silane. Even though Voc and FF were improved, significant reduction in short-circuit photocurrent density (Jsc) was observed after silanization because of desorption of dye during silanization. A new approach, sequential adsorption process of silane and dye, was introduced to enhance Voc and FF without lowering Jsc. Heptadecafluorodecyl trimethoxy-silane showed the highest coverage on the surface of the TiO2 and had the highest effect on the performance improvement of the DSSC, where Voc, FF, and efficiency (η) were improved by 22, 8.0, and 22%, respectively.
从二氧化钛（TiO₂）电极表面到电解质的背向电子转移是染料敏化太阳能电池（DSSC）开路电位（Voc）低和填充因子（FF）低的主要原因。据报道，使用六种不同硅烷的{010}面TiO₂纳米颗粒制备的TiO₂电极经过改性后，可减少TiO₂表面的背向电子转移。研究了碳氢硅烷和碳氟硅烷的烷基链长度对表面覆盖度和吸附常数、界面电阻以及光伏性能等吸附参数的影响。采用吸附等温线、阻抗分析和光伏测量作为研究技术。背向电子转移的减少取决于硅烷在TiO₂表面的覆盖度、烷基链长度以及硅烷的分子结构。尽管Voc和FF有所提高，但硅烷化后观察到短路光电流密度（Jsc）显著降低，这是因为硅烷化过程中染料发生了解吸。引入了一种新方法，即硅烷和染料的顺序吸附过程，以在不降低Jsc的情况下提高Voc和FF。十七氟癸基三甲氧基硅烷在TiO₂表面的覆盖度最高，对DSSC性能改善的效果也最为显著，其中Voc、FF和效率（η）分别提高了22%、8.0%和22%。
