Conjugated polymers with carbazole, fluorene, and ethylene dioxythiophene in the main chain and a pendant cyano group: Synthesis, photophysical, and electrochemical studies

Abstract

Six new conjugated polymers comprising of carbazole, fluorene, and ethylene dioxythiophene (EDOT) moieties along the backbone with a pendant cyano group attached to the ethylene moiety have been designed and synthesized via Sonogashira coupling polymerization reaction. Optical and electrochemical characterizations have shown that the energy band gaps lie within the range of 2.35–2.44 eV. Additionally, the presence of carbazole and EDOT makes these polymers better hole transporting materials, which is reflected from their low oxidation potential peaks (0.55–1.11 V) in cyclic voltammograms. Furthermore, the aggregation enhanced emission (AEE) phenomenon resulted in a 2.6‐fold increase in fluorescence intensity in a 90:10 THF/water mixture in comparison to pristine THF. The AEE properties were further verified by DLS (dynamic light scattering) experiment and SEM (scanning electron microscopy) studies. Polymers in solution as well as in polystyrene matrix emit in the green region (quantum yield in solution state Φf =41–43%) with CIE values (0.25–0.36, 0.52–0.57). Excellent thermal stability is observed for the new polymers. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 2774–2784

Π-Stacking Signature in NMR Solution Spectra of Thiophene-Based Conjugated Polymers

“…Both polythiophenes and thiophene-based polymers can be synthesized by a number of routes spanning from oxidative coupling with FeCl 3 to every kind of catalyzed cross-coupling reaction (e.g., Suzuki, Kumada, and Stille). − A number of books and papers on electro-optical properties and device characterization are found in the literature, ,, but only few of them report the solid-state NMR characterization of blends ,,− or the in-depth NMR investigation of conjugated polymers in solution. − Indeed, papers dealing with the synthesis and characterization of conjugated polymers rarely report even their 1 H NMR spectra, probably because of the discouraging broad line widths found, which seem to prevent a deep investigation.…”

The Different Outcomes of Electrochemical Copolymerisation: 3-Hexylthiophene with Indole, Carbazole or Fluorene

“…Seeing their good solubility in organic solvents, as well as the favourable electronic properties of poly(3-hexylthiophene) (PHT), in our search for new materials, we opted to maintain 3-hexylthiophene as one of the co-monomers and investigate the possibility of coupling it with other conjugated co-monomers. Of those conjugated co-monomers, polycarbazole (Cz), as well as its numerous derivatives are well-known materials for organic electronics, particularly due to their thermal and photochemical stability, high triplet energy and favourable hole-transporting properties [ 40 , 41 ]. Indole (In) itself is relatively less-known, but nevertheless a material showing several beneficial properties good thermal stability, high-redox activity and stability, and slow degradation rate in comparison with polyaniline and polypyrrole [ 33 , 42 , 43 , 44 ] that could favourably supplement the properties of PHT, if successfully copolymerised.…”

Room Temperature Hydrogen Gas Sensing via Reversible Hydrogenation of Electrochemically Deposited Polycarbazole on Interdigitated Pt Transducers

“…Polycarbazole (PCz) and its derivatives are well-known, electroactive, and photoluminescent polymers, with applications as active layers in organic photovoltaics [ 1 , 2 ], corrosion protection [ 3 ], anion [ 4 ], and gas sensors [ 5 , 6 , 7 ]. PCz shows good thermal and photochemical stability, high triplet energy, and relatively high p-type conductivity [ 8 , 9 ].…”