Electronic Processes in Conjugated Diblock Oligomers Mimicking Low Band-Gap Polymers: Experimental and Theoretical Spectral Analysis
Jodi M. Szarko
Brian S. Rolczynski
Jianchang Guo
Yongye Liang
Feng He
Michael W. Mara
Luping Yu
Lin X. Chen
10.1021/jp101925b.s001
https://acs.figshare.com/articles/journal_contribution/Electronic_Processes_in_Conjugated_Diblock_Oligomers_Mimicking_Low_Band_Gap_Polymers_Experimental_and_Theoretical_Spectral_Analysis/2711938
Conjugated oligomers containing a common central thienothiophene unit symmetrically connected to two identical thiophene oligomers were studied as model systems for a series of low bandgap organic diblock copolymers. The oligothiophene side chain fragments were varied in length as a means to tune the electronic coupling between the thienothiophene and oligothiophene moieties. The fragment length dependence of both the ground- and excited-state electronic and structural properties of a series of diblock oligomers were investigated in detail. The charge transfer character in these diblock oligomers, revealed by their optical absorption and fluorescence spectra, is responsible for their low band gap and energy gap tunability compared with their homooligomer counterparts. The electronic spectra and theoretical analysis indicate a partially localized central charge in the first excited state. Using experimental results and comparing them with theoretical calculations, we estimate that the electronic effects from a single thienothiophene unit spreads over seven to nine adjacent units through π-conjugation along the oligomers.
2010-11-18 00:00:00
series
fragment length dependence
oligothiophene side chain fragments
energy gap tunability
Theoretical Spectral AnalysisConjugated oligomers
diblock oligomers
spectra
charge transfer character
thienothiophene unit