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Organic Dye Design Tools for Efficient Photocurrent Generation in Dye‐Sensitized Solar Cells: Exciton Binding Energy and Electron Acceptors
Author(s) -
Kim BongGi,
Zhen ChangGua,
Jeong Eun Jeong,
Kieffer John,
Kim Jinsang
Publication year - 2012
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201101961
Subject(s) - photocurrent , exciton , materials science , energy conversion efficiency , organic solar cell , dye sensitized solar cell , binding energy , density functional theory , electron , multiple exciton generation , photochemistry , moiety , chemical physics , solar cell , optoelectronics , electrolyte , computational chemistry , atomic physics , chemistry , electrode , physics , organic chemistry , condensed matter physics , quantum mechanics , composite material , polymer
The relationship between the exciton binding energies of several pure organic dyes and their chemical structures is explored using density functional theory calculations in order to optimize the molecular design in terms of the light‐to‐electric energy‐conversion efficiency in dye‐sensitized solar cell devices. Comparing calculations with measurements reveals that the exciton binding energy and quantum yield are inversely correlated, implying that dyes with lower exciton binding energy produce electric current from the absorbed photons more efficiently. When a strong electron‐accepting moiety is inserted in the middle of the dye framework, the light‐to‐electric energy‐conversion behavior significantly deteriorates. As verified by electronic‐structure calculations, this is likely due to electron localization near the electron‐deficient group. The combined computational and experimental design approach provides insight into the functioning of organic photosensitizing dyes for solar‐cell applications. This is exemplified by the development of a novel, all‐organic dye (EB‐01) exhibiting a power conversion efficiency of over 9%.