Precise Control of Noncovalent Interactions in Semiconducting Polymers for High-Performance Organic Field-Effect Transistors

Abstract

Performed through side-chain engineering or by incorporating intramolecular locking units, the directionality and dynamic nature of noncovalent interactions are particularly attractive for the design of novel semiconducting materials in a wide variety of applications. This work investigates the nature and position of hydrogen bonding (intra- versus intermolecular), with the objective of developing a rational approach to the design of new semiconducting materials with improved properties in the solid state. To control the polymer chains’ self-assembly, a π-conjugated polymer incorporating a moiety capable of generating intramolecular hydrogen bonding is evaluated against a polymer that allows for intermolecular hydrogen bonding. Characterization through various techniques, optical spectroscopies, grazing incidence wide-angle x-ray scattering, and solution small-angle neutron scattering showed that intramolecular hydrogen bonds resulted in materials with improved crystallinity and higher effective conjugation in the solid state. Additionally, the effect of the noncovalent interaction configuration on the optoelectronic properties was analyzed in organic field-effect transistor fabrication. Devices prepared from the materials with intramolecular hydrogen bonds showed significantly higher performance, with three orders of magnitude higher charge mobility than their counterparts fabricated from polymers with intermolecular hydrogen bonds. These results confirm the importance of chemical design on polymer structures and offer a novel route for the design of high-efficiency semiconducting polymers for next-generation electronics.

Recent Structural Engineering of Polymer Semiconductors Incorporating Hydrogen Bonds

“…The polar carbonyl group in the DPP core enables the molecule to form intramolecular hydrogen bonds, which tune the backbone planarity and the frontier molecular orbital energy levels. [80][81][82] The noncovalent hydrogen bond interactions in the DPP building blocks are different depending on the flanking heterocycles. For example, if the DPP core is flanked by six-membered-ring phenyl groups, the repulsion between the lactam oxygen and the phenyl α-hydrogen causes a twist in the structure.…”

“…The polar carbonyl group in the DPP core enables the molecule to form intramolecular hydrogen bonds, which tune the backbone planarity and the frontier molecular orbital energy levels. [ 80–82 ]…”

From stretchable and healable to self-healing semiconducting polymers: design and their TFT devices

“…Then, underlining the strong impact in the hydrogen bonding units incorporated into conjugated polymer, intramolecular conformational locks can be established resulting in increased backbone planarity, enhanced -delocalization and field-effect mobility ( h FET ). [19][20][21][22] This elegant strategy also brings out new properties and functions, one of which is the self-healing ability (Fig. 1b).…”

“…Furthermore, it was revealed that the incorporation of hydrogen bonding moieties among these novel conjugated polymer designs is particularly effective in tailoring the mechanical deformability and maintaining or even boosting the charge transport values in TFTs. [19][20][21][22] Interestingly, the combination of dynamic H-bonds into organic semiconductors has brought out new property and function such as self-healing ability which will be explained in the Section 3. [23][24][25] 2.2.1 Block copolymer approach.…”

Molecular engineering of benzothiadiazole-based polymers: balancing charge transport and stretchability in organic field-effect transistors

“…The incorporation of fluorine atoms can be advantageous since it can potentially allow for strain dissipation upon stress through non-covalent H-F bonds. 35,36 On the other ends, fluorination can result in the p-conjugated backbone to become more planar, thus increasing crystallinity and the rigidity of the macromolecule.…”