An Asymmetric Furan/Thieno[3,2‐b]Thiophene Diketopyrrolopyrrole Building Block for Annealing‐Free Green‐Solvent Processable Organic Thin‐Film Transistors

Abstract

A new asymmetric furan and thieno[3,2-b]thiophene flanked diketopyrrolopyrrole (TTFDPP) building block for conjugated polymers is designed and used to generate a donor-acceptor semiconducting polymer, poly[3-(furan-2-yl)-2,5-bis(2-octyldodecyl)-6-(thieno[3,2-b]thiophen-2-yl)pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione-alt-thieno[3,2-b]thiophene] (abbreviated to PTTFDPP-TT), consisting of TTFDPP unit copolymerized with thieno[3,2-b]thiophene comonomer (TT), which is further synthesized. Results demonstrate that PTTFDPP-TT-based thin-film transistors in a bottom-gate bottom-contact device configuration exhibit typical hole-transporting property, with weak temperature dependence for charge carrier mobility from room temperature to 200 °C. In addition, the good solubility of PTTFDPP-TT due to the incorporation of a polar furan unit and an asymmetric conjugated structure makes it able to be solution processed with a less toxic nonchlorinated solvent such as toluene, demonstrating comparable performance with that prepared from chlorinated solution. These results suggest PTTFDPP-TT as a promising organic semiconductor candidate for annealing-free, environmentally benign, and less energy-consuming applications in large-area flexible organic electronic devices.

A Simple Structure Conjugated Polymer for High Mobility Organic Thin Film Transistors Processed from Nonchlorinated Solvent

“…A common method to increase solubility in nonchlorinated solvent is to reduce regioregularity by random copolymerization of asymmetric monomers or more than two monomers . Another method is to introduce solubilizing side chains other than alkyls to increase solute–solvent compatibility .…”

Recent structural evolution of lactam- and imide-functionalized polymers applied in organic field-effect transistors and organic solar cells

“…4a). 51 The DFT simulation revealed a planar backbone, with dihedral angles no more than 3.2 in the TTFDPP moiety (Fig. 4b), and delocalized HOMO/LUMO orbitals over the whole molecular backbone.…”

Well-balanced ambipolar diketopyrrolopyrrole-based copolymers for OFETs, inverters and frequency doublers

“…The copolymer PPyTDPP-2FBT exhibits typical dual-band absorption. The lower absorption band (band I: 350-550 nm) can be attributed to the internal charge transfer (ICT) transitions, and the higher absorption band (band II: 550-850 nm) is derived from the π-π transition [36,44]. Compared to the solution spectrum, the maximum absorption peak (λ max ) in the solid state was red-shifted by approximately 7 nm, which demonstrates the effective formation of π-π stacking in the PPyTDPP-2FBT, probably due to its intrinsically good coplanarity.…”

“…As expected, the ambipolar charge transport property in OFETs was achieved for the synthesized PPyTDPP-BT polymers which could also be used as donor or acceptor materials in polymer solar cells for high power conversion efficiencies. Such asymmetric flanked unit design strategy was further successfully applied for other DPP-based copolymers for optoelectronic devices [36,37]. From our previous experience, these asymmetric DPP-based polymers possess features of easy synthesis, and good film-forming characteristic with weak dependence on experimental conditions and the surrounding environment, which is very crucial for large-area device applications.…”