Alternating Conjugated Electron Donor–Acceptor
Polymers Entailing Pechmann Dye Framework as the Electron Acceptor
Moieties for High Performance Organic Semiconductors with Tunable
Characteristics
- Publication date
- Publisher
Abstract
In
this paper, we report the design, synthesis and semiconducting
behavior of two conjugated D–A polymers <b>P-BPDTT</b> and <b>P-BPDBT</b> which entail <b>BPD</b>, a Pechmann
dye framework, as electron accepting moieties, and thieno[3,2-<i>b</i>]thiophene and 2,2′-bithiophene as electron donating
moieties. Their HOMO/LUMO energies and bandgaps were estimated based
on the respective cyclic voltammgrams and absorption spectra of thin
films. <b>P-BPDTT</b> possesses lower LUMO level and narrower
bandgap than <b>P-BPDBT</b>. On the basis of the characterization
of the field-effect transistors, a thin film of <b>P-BPDTT</b> exhibits ambipolar semiconducting properties with hole and electron
mobilities reaching 1.24 cm<sup>2</sup> V<sup>–1</sup> s<sup>–1</sup> and 0.82 cm<sup>2</sup> V<sup>–1</sup> s<sup>–1</sup>, respectively, after thermal annealing. In comparison,
thin film of <b>P-BPDBT</b> only shows <i>p</i>-type
semiconducting behavior with hole mobility up to 1.37 cm<sup>2</sup> V<sup>–1</sup> s<sup>–1</sup>. AFM and XRD studies
were presented to understand the interchain arrangements on the substrates
and the variation of carrier mobilities