Effect of hexyl substituent groups on photophysical and electrochemical properties of the poly[(9,9‐Dioctyluorene)−2,7‐diyl‐alt‐(4,7‐bis (3‐Hexylthien‐5‐Yl)−2,1,3‐Benzothiadiazole)−2′,2″‐diyl]

Abstract

The effect of the presence of hexyl group in thiophene on the photophysical and electrochemical properties of poly[(9,9-dioctyluorene)22,7-diyl-alt-(4,7-bis(3-hexylthien-5-yl)22,1,3-benzothiadiazole)22The copolymers present electron donor-acceptor architecture and are synthesized by Suzuki coupling reaction. The UV/Vis spectra show absorption maximum in the wavelength range of blue and orange, which are associated with different segments of the polymer backbone. Addition of hexyl substituent groups has a positive effect on the molar absorptivity and increases the emission and absorption intensities due to fluorene and thiophene-benzothiadiazole-thiophene (TBT) units, although an increment in the bandgap is observed. Cyclic voltammetry study of the polymer films reveal irreversible reduction and oxidation processes of the TBT units in the polymer chain and the HOMO and LUMO energy levels suggest ambipolar character for the polymers, while the electrochemical bandgaps are consistent with the absorbance measurements.

Solvent effects on the morphology and electrical conductivity of a D‐A random copolymer with low band gap

“…It was not used λ exc values less than 400 nm for F8 excitation due to the presence of overtons that holds back the fluorescence emission from polymeric film on the glass substrate. But it is important to highlight the overlap between absorption and emission bands enables self‐absorption and Förster resonance energy transfer (FRET) between F8 and TBT chromophores in the polymer chains and, consequently, the presence of only TBT emission band in the fluorescence spectra of the polymer in the solid state.…”

A new polymer acceptor containing naphthalene diimide and 1,3,4‐thiadiazole for all‐polymer solar cells

“…To effectively tune the energy level, the strategy for designing n‐type polymers is usually to alternately arrange the electron donor and acceptor units on the polymer backbone . Among these n‐type conjugated polymer acceptors, naphthalene diimide (NDI) based copolymers have attracted much interest in electronic devices due to their high electron mobility, electron affinity and intense light absorption ability both in the visible and near‐infrared region .…”