In a series of n‐type semiconducting naphthalene tetracarboxydiimide (
Mechanically deformable polymeric semiconductors are a key material for fabricating flexible organic thin‐film transistors (FOTFTs)—the building block of electronic circuits and wearable electronic devices. However, for many π‐conjugated polymers achieving mechanical deformability and efficient charge transport remains challenging. Here the effects of polymer backbone bending stiffness and film microstructure on mechanical flexibility and charge transport are investigated via experimental and computational methods for a series of electron‐transporting naphthalene diimide (NDI) polymers having differing extents of π‐conjugation. The results show that replacing increasing amounts of the π‐conjugated comonomer dithienylvinylene (TVT) with the π‐nonconjugated comonomer dithienylethane (TET) in the backbone of the fully π‐conjugated polymeric semiconductor, PNDI‐TVT100(yielding polymeric series PNDI‐TVT
- Award ID(s):
- 2223922
- PAR ID:
- 10469397
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Functional Materials
- ISSN:
- 1616-301X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract In a series of n‐type semiconducting naphthalene tetracarboxydiimide (
NDI )‐dithiophene (T2 ) copolymers, structural and electronic properties trends are systematically evaluated as the number ofNDI carbonyl groups is reduced from 4 inNDI to 3 inNBL (1‐amino‐4,5‐8‐naphthalene‐tricarboxylic acid‐1,8‐lactam‐4,5‐imide) to 2 inNBA (naphthalene‐bis(4,8‐diamino‐1,5‐dicarboxyl)‐amide). As theNDI ‐T2 backbone torsional angle falls the LUMO energy rises. However, the thienyl attachment regiochemistry also plays an important role in less symmetricNBL andNBA . Electron mobility is greatest forN2200 (0.17 cm2 V−1 s−1) followed byPNBL‐3,8‐T2 andPNBA‐2,6‐T2 (0.11 cm2 V−1 s−1), 0.02 cm2 V−1 s−1inPNBL‐4,8‐T2 , and negligible inPNBA‐3,7‐T2 . Charge transport reflects a delicate balance between electronic backbone communication (optimum forN2200 andPNBL‐4,8‐T2 ), backbone planarity (optimum forPNBA‐2,6‐T2 andPNBL‐3,8‐T2 ), LUMO energy (optimum forN2200 ), π–π stacking distance (optimum forPNBA‐2,6‐T2 ), and film crystallinity (optimum forPNBA‐2,6‐T2 andN2200 ). These results offer generalizable insight into semiconducting copolymer design. -
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