Journal of the American Chemical Society 2006-11-08

Alkyl-functionalized organic dyes for efficient molecular photovoltaics.

Nagatoshi Koumura, Zhong-Sheng Wang, Shogo Mori, Masanori Miyashita, Eiji Suzuki, Kohjiro Hara

Index: J. Am. Chem. Soc. 128 , 14256, (2006)

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Abstract

We designed and synthesized new alkyl-functionalized organic dyes, MK-1 and MK-2, for dye-sensitized solar cells (DSSCs). Based on the MK-2 dye, a high performance of efficiency (eta, 7.7%; short-circuit current density Jsc = 14.0 mA cm-2, open-circuit voltage Voc = 0.74 V, and fill factor FF = 0.74) was achieved under AM 1.5 G irradiation (100 mW cm-2). Remarkably, the relatively higher Voc for DSSCs based on MK-1 and MK-2 dyes, which have long alkyl chains, were observed among the organic dyes caused by the increasing of the electron lifetime in the conduction band of TiO2. Our molecular design of alkyl-functionalized dyes strongly suggests the promising performance of molecular photovoltaics based on organic dyes.