Effects of 5-Membered Heteroaromatic Spacers on Structures of Porphyrin Films and Photovoltaic Properties of Porphyrin-Sensitized TiO2 Cells

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• 作者：Seunghun Eu ; Shinya Hayashi ; Tomokazu Umeyama ; Akane Oguro ; Mitsuo Kawasaki ; Naoki Kadota ; Yoshihiro Matano ; Hiroshi Imahori
• 刊名：Journal of Physical Chemistry C
• 出版年：2007
• 出版时间：March 1, 2007
• 年：2007
• 卷：111
• 期：8
• 页码：3528 - 3537
• 全文大小：258K
• 年卷期：v.111,no.8(March 1, 2007)
• ISSN：1932-7455

文摘

Novel 5-(5-carboxy-2-thienyl)-10,15,20-tris(2,4,6-trimethylphenyl)-porphyrinatozinc(II) (Zn5S), 5-(5-carboxy-2-furyl)-10,15,20-tris(2,4,6-trimethylphenyl)porphyrinatozinc(II) (Zn5O), and 5-(4-carboxy-2-thienyl)-10,15,20-tris(2,4,6-trimethylphenyl)porphyrinatozinc(II) (Zn4S) were synthesized to evaluate the spacer effects onthe structures of the porphyrin films and the photovoltaic properties of the porphyrin-sensitized TiO₂ solarcells. Each of the porphyrins showed different adsorption behavior and saturated coverage on the TiO₂ surfaceand photovoltaic properties depending on the identity of heteroatoms in the bridge and the position of carboxylicacid. Specifically, Zn5S-sensitized TiO₂ cell displayed larger, maximum incident photon-to-current efficiencyof 65% and maximum power conversion efficiency of 3.1% than Zn5O-sensitized TiO₂ cell by ~20% and~40%, respectively. We interpret that these results are stemmed from ancillary electron-transfer pathwaythrough specific interaction between a sulfur atom in the bridge of Zn5S and the TiO₂ surface. Opticalspectroscopy, attenuated total reflectance-Fourier transform infrared spectroscopy, X-ray photoelectronspectroscopy, density functional theory calculations, and photovoltaic measurements under standard AM 1.5conditions were employed to support our proposal.