Fabrication and Characterization of Titanium Oxide Nanotube-based Dye Sensitized Solar Cells

• Main Authors: Wu, Po-Ting, 吳柏霆
• Other Authors: Diau, Wei-Guang
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/hey663

碩士 === 國立交通大學 === 應用化學系碩博士班 === 101 === Self-organized 1-D titania nanotube (TNT) arrays have a great potential as materials for photocatalysis, self-cleaning, gas sensing, lithium batteries and dye-sensitized solar cells (DSSC) due to their excellent charge collection efficiency and slow charge recombination. In this work we fabricated highly efficient TiO2 nanotubes-based dye-sensitized solar cells sensitized by novel heteroleptic ruthenium dyes, RD16-RD18, and studied electron transport and charge recombination kinetics of the relative devices using transient photocurrent/photovoltage decay and charge extraction techniques. A series of heteroleptic ruthenium complexes RD16-RD18 containing fluoro- substituted and thiophene-based benzimidazole ligands were developed by Professor Diau’s group. The RD16-sensitized TNT-DSSC reveals an enhanced short-circuit current density (JSC) and efficiency (?? of power conversion compared to N719 due to the increasing light-harvesting and the broadened spectral features with thiophene-based ligands. However, the devices made of RD17 and RD18 were confronted by the poor adsorption of dyes on TNT surface resulting in a decreased short-circuit current density especially in RD18. Instead of retarding charge recombination, the substitution of thiophene and long alkyl chain in RD17 and RD18 caused an aggregation of sensitizers. Investigating using the photovoltage decay and charge extraction measurements, we found that the TiO2 potential shift downward in a systematic trend of Ecb : RD16 < RD17 < RD18 and the electron lifetimes show the order of RD17 ?d RD16 ＞ RD18. In order to preventing the aggregation, co-absorber, DINHOP and CDCA, were introduced in RD sensitizers. Upon optimization, the device made of RD16 yielded JSC/mA cm-2 = 14.98, VOC/mV = 714, FF = 0.67 and the efficiency reaches 7.18 %.