Computational Investigation of Dye鈥揑odine Interactions in Organic Dye-Sensitized Solar Cells

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• 作者：Mariachiara Pastore ; Edoardo Mosconi ; Filippo De Angelis
• 刊名：The Journal of Physical Chemistry C
• 出版年：2012
• 出版时间：March 8, 2012
• 年：2012
• 卷：116
• 期：9
• 页码：5965-5973
• 全文大小：451K
• 年卷期：v.116,no.9(March 8, 2012)
• ISSN：1932-7455

文摘

We present a computational investigation, based on DFT, MP2, and Car鈥揚arrinello molecular dynamics simulations, aimed to model the dye鈥搃odine interactions in organic dye-sensitized solar cells. We evaluate the binding of I₂ and I₃^{鈥?/sup> and Li+ to the various electron-donating sites in organic sensitizers considering two coumarin dyes differing by the number of thiophene rings in the bridge (NKX2587 vs NKX2697) and one carbazole dye (MK3), which have been the subject of a detailed experimental investigation (J. Am. Chem Soc.2008, 130, 17874鈥?7881). We find that oxygen atoms are the preferred binding sites for I₂, while I₃鈥?/sup> tends to interact with the 蟺 system of the coumarin donor unit. Our results suggest that the increase of the distance of the carbonyl oxygen from the titania going from NKX2587 to NKX2697 could explain the differences in the lifetime values measured for NKX2587-sensitized solar cells compared to those employing the longer NKX2697 homologues. The shorter lifetime measured for MK3 compared to NKX2687, which have the same 蟺-spacer and acceptor units, is instead attributed to the twisting of the dye structure in MK3, which possibly forms less compact dye layers on titania. The effect of the dye structure and Li+ coordination to the dyes on the titania conduction band is also examined.}