PreprintArticleVersion 1Preserved in Portico This version is not peer-reviewed
Photophysical, Thermal and Structural Properties of Thiophene and Benzodithiophene-Based Copolymers Synthesized by Direct Arylation Polycondensation Method
Tegegne, N.A.; Abdissa, Z.; Mammo, W. Photophysical, Thermal and Structural Properties of Thiophene and Benzodithiophene-Based Copolymers Synthesized by Direct Arylation Polycondensation Method. Polymers2021, 13, 1151.
Tegegne, N.A.; Abdissa, Z.; Mammo, W. Photophysical, Thermal and Structural Properties of Thiophene and Benzodithiophene-Based Copolymers Synthesized by Direct Arylation Polycondensation Method. Polymers 2021, 13, 1151.
Tegegne, N.A.; Abdissa, Z.; Mammo, W. Photophysical, Thermal and Structural Properties of Thiophene and Benzodithiophene-Based Copolymers Synthesized by Direct Arylation Polycondensation Method. Polymers2021, 13, 1151.
Tegegne, N.A.; Abdissa, Z.; Mammo, W. Photophysical, Thermal and Structural Properties of Thiophene and Benzodithiophene-Based Copolymers Synthesized by Direct Arylation Polycondensation Method. Polymers 2021, 13, 1151.
Abstract
Three low band gap copolymers based on isoindigo acceptor units were designed and successfully synthesized by direct arylation polycondensation method. Two of them were benzodithiophene(BDT)-isoindigo copolymers (PBDTI-OD and PBDTI-DT) with 2-octlydodecyl(OD) and 2-decyltetradecyl (DT) substituted isoindigo units, respectively. Thiophene donor and DT-substituted isoindigo acceptor units were copolymerized to synthesize PTI-DT. The copolymers have broad absorption range that extends to over 760 nm with a band gap ~ .5 eV. The photophysical property studies showed the BDT based copolymers have non-polar ground states. Their emission exhibited the population of intramolecular charge transfer (ICT) state in polar solvents and tightly bound excitonic state in non-polar solvents due to self-aggregation. On the contrary, the emission from the thiophene based copolymers was only from the tightly bound excitonic state. The thermal decomposition temperature of the copolymers was above 380 oC. The X-ray diffraction pattern of the three copolymers showed a halo due pi-pi stacking. A second sharper peak was observed in the BDT-based copolymer with longer side chain on the isoindigo unit (PBDTI-DT) and the thiophene based copolymers with PTI-DT exhibiting a better structural order.
Keywords
Intramolecular charge transfer; copolymers; pi-pi stacking; direct arylation polycondensation; excitonic state
Subject
Chemistry and Materials Science, Biomaterials
Copyright:
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.