Optimization of Multiple Electron Donor and Acceptor in Carbazole-Triphenylamine-Based Molecules for Application of Dye-Sensitized Solar Cells

• Published in: Journal of physical chemistry. C Vol. 114; no. 49; pp. 21786 - 21794
• Main Authors: Yang, Chien-Hsin, Liao, Shao-Hong, Sun, Yu-Kuang, Chuang, Yao-Yuan, Wang, Tzong-Liu, Shieh, Yeong-Tarng, Lin, Wen-Churng
• Format: Journal Article
• Language: English
• Published: American Chemical Society 16.12.2010
• Subjects: C: Energy Conversion and Storage
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/jp106275v

Organic dyes have been synthesized which containing multiple electron donors (carbazole) and electron acceptors (rhodaniline-3-acetic acid) on triphenylamine (TPA). Photophysical, electrochemical, and theoretical computational methods have categorized these compounds. Nanocrystalline TiO2-based dye-sensitized solar cells (DSSCs) are fabricated using these dye molecules as light-harvesting sensitizers. The overall efficiency of sensitized cells is high (4.64%) as compared to a cis-di(thiocyanato)-bis(2,2′-bipyridyl)-4,4′-dicarboxylate ruthenium(II) (N3 dye)-sensitized device (7.83%) fabricated and measured under the same conditions. Both electron donor (carbazole) and acceptor (rhodaniline-3-acetic acid) play a key role in the increased efficiency. One carbazole and two rhodaniline-3-acetic acid-based dye appears to help convey the charge transfer from the excited dye molecules to the conduction band of TiO2, leading to a higher efficiency of the assembled devices using such a dye. Electrochemical impedance measurements support this dye’s effect on enhancing charge transfer of TiO2 (e−). Computation on this CTPAR2 compound also indicates a larger charge transfer efficiency in the electronically excited state.