Molecular Design of Coumarin Dyes for Stable and Efficient Organic Dye-Sensitized Solar Cells

• Published in: Journal of physical chemistry. C Vol. 112; no. 43; pp. 17011 - 17017
• Main Authors: Wang, Zhong-Sheng, Cui, Yan, Dan-oh, Yasufumi, Kasada, Chiaki, Shinpo, Akira, Hara, Kohjiro
• Format: Journal Article
• Language: English
• Published: American Chemical Society 30.10.2008
• Subjects: C: Energy Conversion and Storage
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/jp806927b

A series of coumarin dyes (NKX-2593, NKX-2807, and NKX-2883) with one or two -CN groups as electron acceptors were synthesized and applied as dye sensitizers for dye-sensitized solar cells. Compared with the dye containing one -CN group, linking one more -CN group to the π-conjugation bridge positively shifts the lowest unoccupied molecular orbital and thus red-shifts the maximum absorption band, harvesting more photons in the long-wavelength region for photoelectric conversion. Among the three dyes studied, NKX-2883 showed the best photovoltaic performance, yielding 7.6% power conversion efficiency using a volatile electrolyte and demonstrating good photostability under visible light soaking with 6% of power conversion efficiency for 1000 h using a nonvolatile electrolyte.