Theoretical Solar-to-Electrical Energy-Conversion Efficiencies of Perylene-Porphyrin Light-Harvesting Arrays

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• 作者：Georg M. Hasselman ; David F. Watson ; Jonathan R. Stromberg ; David F. Bocian ; Dewey Holten ; Jonathan S. Lindsey ; Gerald J. Meyer
• 刊名：Journal of Physical Chemistry B
• 出版年：2006
• 出版时间：December 21, 2006
• 年：2006
• 卷：110
• 期：50
• 页码：25430 - 25440
• 全文大小：360K
• 年卷期：v.110,no.50(December 21, 2006)
• ISSN：1520-5207

文摘

The efficiencies of organic solar cells that incorporate light-harvesting arrays of organic pigments werecalculated under 1 sun of air mass 1.5 solar irradiation. In one set of calculations, photocurrent efficiencieswere evaluated for porphyrin, phthalocyanine, chlorin, bacteriochlorin, and porphyrin-bis(perylene) pigmentarrays of different length and packing densities under the assumption that each solar photon absorbedquantitatively yielded one electron in the external circuit. In another more realistic set of calculations, solarconversion efficiencies were evaluated for arrays comprising porphyrins or porphyrin-(perylene)₂ units takinginto account competitive excited-state relaxation pathways. A system of coupled differential equations for allreactions in the arrays was solved on the basis of previously published rate constants for (1) energy transferbetween the perylene and porphyrin pigments, (2) excited-state relaxation of the perylene and porphyrinpigments, and (3) excited-state electron injection into the semiconductor. This formal analysis enablesdetermination of the optimal number of pigments in an array for solar-to-electrical energy conversion. Theoptimal number of pigments depends on the molar absorption coefficient and the density at which the arrayscan be packed on an electrode surface. Taken together, the ability to employ fundamental photophysical,kinetic, and structural parameters of modular molecular architectures in assessments of the efficiency of solar-to-electrical energy conversion should facilitate the design of molecular-based solar cells.