High n-type and p-type conductivities and power factors achieved in a single conjugated polymer

Abstract

The charge transport properties of conjugated polymers are commonly limited by the energetic disorder. Recently, several amorphous conjugated polymers with planar backbone conformations and low energetic disorder have been investigated for applications in field-effect transistors and thermoelectrics. However, there is a lack of strategy to finely tune the interchain π-π contacts of these polymers that severely restricts the energetic disorder of interchain charge transport. Here, we demonstrate that it is feasible to achieve excellent conductivity and thermoelectric performance in polymers based on thiophene-fused benzodifurandione oligo( p -phenylenevinylene) through reducing the crystallization rate of side chains and, in this way, carefully controlling the degree of interchain π-π contacts. N-type (p-type) conductivities of more than 100 S cm −1 (400 S cm −1 ) and power factors of more than 200 μW m −1 K −2 (100 μW m −1 K −2 ) were achieved within a single polymer doped by different dopants. It further demonstrated the state-of-the-art power output of the first flexible single-polymer thermoelectric generator.

Electron transfer driving force as the criterion for efficient n-doping of organic semiconductors with DMBI-H derivatives

“…9–11 However, except for a very recently reported n-type polymer that shows ultrahigh σ over 2000 S cm −1 , 12 n-type OSCs rarely have σ over 100 S cm −1 . 13–16 Controllable chemical doping based on redox reactions is one of the most effective strategies to tune the σ of OSCs. 17,18 For simply efficient electron transfer (ET), the ionization energy (IE) of reducing agents should be lower than the electron affinity (EA) of OSCs, which reduces the air stability of n-dopants.…”

Polymer Semiconductors: Synthesis, Processing, and Applications

“…54,447 In 2023, they reported N-DMBI-doped TBDOPV-T-518 with a non-hopping transport characteristic. 289 TBDOPV-T-518 could exhibit both high n-type and p-type conductivities >100 S cm −1 and power factors >100 μW 59). Using the same thermoelectromotive force, polymer semiconductors can also be for temperature detection.…”

“…Branching position of chains: moving the branching points away from the backbones might decrease the interchain π–π stacking distance and affects crystallinity and thin film microstructures. For example, Pei and co-workers systematically investigated the effect of side-chain branching position on electronic properties in conjugated polymers. ,− In the BDPPV-based polymers with alkyl side chains branched at different positions, the interchain π–π stacking distance decreases as moving the branching position away from polymer backbones. But the decreased π–π stacking distance does not always boost the electron mobility.…”

“…The odd–even effect (with alkyl chains branched in odd/even-numbered positions or chain length with odd/even-number atoms) is normally observed but remains puzzling. , It might be caused by the different zigzag conformation of alkyl chains . A farther side chain branching point will also lead to higher disorders of side chains, which provides better miscibility in the doping process without harming original chain packings and charge transport channels, achieving high electronic properties of doped polymer systems (Figure b,c). , …”

“…Copyright 2014 John Wiley and Sons. (b) Reproduced with permission from ref . Copyright 2023 American Association for the Advancement of Science under a CC-BY-NC license.…”