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Evolution of the Excited‐State Dynamics of 2 H ‐Dinaphthopentacene Based Dyes in Dye‐Sensitized Solar Cells: From Chromophoric Core to Ultimate Dye
Author(s) -
Liu Jiao,
Ren Yameng,
Zhang Min,
Dong Xiandui
Publication year - 2018
Publication title -
solar rrl
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.544
H-Index - 37
ISSN - 2367-198X
DOI - 10.1002/solr.201800119
Subject(s) - excited state , chromophore , photochemistry , chemistry , acceptor , organic solar cell , chemical physics , dissociation (chemistry) , intramolecular force , stokes shift , exciton , materials science , atomic physics , optoelectronics , luminescence , organic chemistry , polymer , physics , condensed matter physics , quantum mechanics
The excited‐state evolution property of organic sensitizers plays a vital role in the interfacial exciton dissociation yield and ultimate power output of an organic dye‐sensitized solar cell. In this paper, we select two 2 H ‐dinaphthopentacene‐based organic donor–acceptor dyes as well as their composition segments and scrutinize the evolution of the excited‐state dynamics of organic materials from the 2 H ‐dinaphthopentacene core to its derivatives by sequentially tethering an auxiliary donor diarylamine, and an electron acceptor, 4‐(7‐ethynylbenzo[ c ][1,2,5]thiadiazol‐4‐yl)benzoic acid. Time‐resolved spectroscopy measurements and density functional theory calculations show that the degree of intramolecular photoinduced charge transfer plays a crucial role in determining the lifetime of the equilibrium excited‐state. Moreover, both the 2 H ‐dinaphthopentacene chromophore core and its derivatives have an obvious dynamic Stokes shift in toluene, which is also observed for ultimate dyes grafted on oxide films, indicating the occurrence of a large energy relaxation from the optically generated hot excited‐state to the equilibrium excited‐state. This large energy loss leads to a broad time scale for electron injection, which should be carefully manipulated for future dye and device development.