title: Enhanced Charge Separation Efficiency in Pyridine-Anchored Phthalocyanine-Sensitized Solar Cells by Linker Elongation.
abstract: A series of zinc phthalocyanine sensitizers (PcS22-24) having a pyridine anchoring group are designed and synthesized to investigate the structural dependence on performance in dye-sensitized solar cells. The pyridine-anchor zinc phthalocyanine sensitizer PcS23 shows 79 % incident-photon to current-conversion efficiency (IPCE) and 6.1 % energy conversion efficiency, which are comparable with similar phthalocyanine dyes having a carboxylic acid anchoring group. Based on DFT calculations, the high IPCE is attributed with the mixture of an excited-state molecular orbital of the sensitizer and the orbitals of TiO2 . Between pyridine and carboxylic acid anchor dyes, opposite trends are observed in the linker-length dependence of the IPCE. The red-absorbing PcS23 is applied for co-sensitization with a carboxyl-anchor organic dye D131 that has a complementary spectral response. The site-selective adsorption of PcS23 and D131 on the TiO2 surface results in a panchromatic photocurrent response for the whole visible-light region of sun light.
authors.affiliation: Division of Chemistry and Materials, Faculty of Textile Science and Technology, Shinshu University, Ueda, 386-8567, Japan.
authors.forename: Takuro
authors.initials: T
authors.lastname: Ikeuchi
authors.affiliation: Division of Chemistry and Materials, Faculty of Textile Science and Technology, Shinshu University, Ueda, 386-8567, Japan.
authors.forename: Saurabh
authors.initials: S
authors.lastname: Agrawal
authors.affiliation: Yamamoto Chemicals Inc., Yao, 581-0034, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Ezoe
authors.affiliation: Division of Chemistry and Materials, Faculty of Textile Science and Technology, Shinshu University, Ueda, 386-8567, Japan. shogmori@shinshu-u.ac.jp.
authors.forename: Shogo
authors.initials: S
authors.lastname: Mori
authors.affiliation: Division of Chemistry and Materials, Faculty of Textile Science and Technology, Shinshu University, Ueda, 386-8567, Japan. mkimura@shinshu-u.ac.jp.
authors.forename: Mutsumi
authors.initials: M
authors.lastname: Kimura
keywords: TiO2; dyes/pigments; energy conversion; phthalocyanines; solar cells