Directional Carrier Polarity Tunability in Ambipolar Organic Transistors Based on Diketopyrrolopyrrole and Bithiophene Imide Dual-Acceptor Semiconducting Polymers

Abstract

An organic ambipolar transistor allows the integration of p-type and n-type charge carrier transport in a single device. However, the tunability of carrier polarity to meet specific requirements for practical applications is challenging and thus rarely studied. In this work, two dual-acceptor-type polymers (FuI and SeI) based on diketopyrrolopyrrole (DPP) and bithiophene imide (BTI) are reported. By varying the flanking groups of DPP (furan for FuI and selenophene for SeI) and through an ionic additive strategy, the charge carrier polarity of both polymers in organic field-effect transistors (OFETs) can be directionally tuned. Specifically, pristine polymers exhibited an ambipolar property with the μe/μh values of 2.79 for FuI and 4.9 for SeI. Notably, the average electron mobility of SeI reaches as high as 0.122 cm2 V–1 s–1. More encouragingly, with 11.76% tetrabutylammonium iodide (TBAI, mole percentage) as an additive to the FuI polymer, the μe/μh of resultant OFETs varied from 2.79 to 0.71, showing the conversion from n-type dominant to p-type dominant transport. With the same mole percentage of the TBAI to SeI polymer, a dramatic increment of μe/μh from 4.9 to 264 was observed, demonstrating the significant conversion from n-type dominant ambipolar to unipolar n-type transport. Overall, this study demonstrates the possibility of directional tunability of carrier polarity in organic ambipolar transistors with DPP- and BTI-based dual-acceptor polymers through molecular modification and the ionic additive strategy, being significantly beneficial for complementary circuits.

Tuning the nanostructure and molecular orientation of high molecular weight diketopyrrolopyrrole-based polymers for high-performance field-effect transistors

“…1 The long-range ordered regions with lower paracrystalline disorder resulted in improved charge transport in field-effect transistors. 16…”

“…1 The long-range ordered regions with lower paracrystalline disorder resulted in improved charge transport in field-effect transistors. 16 Besides film morphologies, polymer packing orientation in the solid state is also of crucial importance to the transistor performance. The edge-on orientation, where the polymer backbones are oriented perpendicular to the substrate surface, is favourable to charge transport in planar transistors, because the resultant π-stacking direction is parallel to the conduction channel.…”

An extended quinoid molecule based on bis(thiophene-diketopyrrolopyrrole) with balanced ambipolar semiconducting properties and strong near-infrared absorption

“…Diketopyrrolopyrrole (DPP) derivatives, owing to their strong light absorption and thermal and photochemical stability, as well as good charge transport properties, have been widely explored for developing high performance organic/polymeric semiconductors. 30–41 DPP-based conjugated donor–acceptor polymers have been prepared and found to show p-type, n-type and even ambipolar semiconducting behaviors, depending on the features of the donor units and the connection manner of the donor and DPP units. The hole and electron mobilities of these DPP-based polymeric p- and n-type semiconductors have already exceeded 10 cm 2 V −1 s −1 and 1 cm 2 V −1 s −1 , respectively, 42–44 while the respective hole and electron mobilities of the ambipolar semiconductors have become higher than 8.0 and 4.0 cm 2 V −1 s −1 .…”

Organic Field Effect Transistors Comprising Copolymers Synthesized without Structure-Directing Moieties with Enhanced Carrier Mobility

“…Conjugated polymers are widely used in a variety of devices including field effect transistors, organic solar cells, and light emitting diodes. − The polymers are synthesized by C–C bond forming reactions such as Suzuki and Stille coupling reactions. , In Suzuki coupling, aryl bromide is reacted with aryl organoboron compounds in the presence of a Pd catalyst . The organoborons are considered to be the directing group.…”