Rigid Coplanar Polymers for Stable n‐Type Polymer Thermoelectrics

Abstract

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The effect of aromatic ring size in electron deficient semiconducting polymers for n-type organic thermoelectrics

“…Considering the strong in-plane p-stack scattering, noticeable out-of-plane p-stack scattering and multiple out-of-plane lamellar scattering, P2 is speculated to possess a predominant population of edge-on orientated crystallites and a significant minority population of face-on orientated crystallites. The structure of P1 and P2 was nominally similar to that reported for the all phenyl analogue, 41 with pronounced out-of-plane p-stack scattering and an isotropic amorphous scattering ring. However, while increasing the alkyl branch length in the all phenyl analogue diminished ordering and decreased scattering intensity (with an accompanying diminishment in charge transport), here increasing the alkyl branch length did not significantly decrease ordering or scattering intensity, but instead induced increased edge-on texture with minimal change in charge transport.…”

The effect of alkyl side chain length on the formation of two semi-crystalline phases in low band gap conjugated polymers

“…This observation implies that CF still plays a certain role in the self-assembly of P-PDPP4T-HD. [54][55][56][57] As expected, the length of linear alkyl chains is reflected in d lam , which increases from 1.9 to 2.5 nm with side chain length from hexyl to pentadecyl (Fig. 6c).…”

Conformation Control of Conjugated Polymers

“…[22,55] Isoindigo( IID) and BDOPV( 3)a re two traditional rigidb uilding blocks that are linked by double bonds inside the small molecules. [22,55] Based on their molecular structure, an ovel synthetic methodo fp olymerization via aldol condensation reaction was developedb yM cCulloch group [56] (Scheme 10 a) and our group [57] (Scheme 10 b). Bifunctionalg roup monomers (bisisatin with bis-oxindoleo rb enzodifurandione) are used to synthesize double-bondl inked conjugated polymers by acid-catalyzed aldol polymerization without organometallicm onomers or metal catalysts.…”

“…As ar esult,amaximum electron mobility of 0.03 cm 2 V À1 s À1 was achieved in thin-filmd evices of 22.I n 2019, our group designed and synthesized LPPV (23)a sp olymer thermoelectric materials with high doping efficiency and good air stability (Scheme 10 b). [57] The double-bond connections, togetherw ith nontraditional hydrogen bonds, endow LPPV (23)w ith small torsional angles of 6.1(AE 5.68)8 and high torsional barrier of more than 30 kcal mol À1 ,w hich provide an efficient one-dimensional intrachain charge transfer.Alow LUMO level of LPPV (23), down to À4.49 eV,w as favorable to improvet heir doping efficiency.Amaximalc onductivity of 1.1 Scm À1 and ap ower factor of 1.96 mWm À1 K À2 were obtained in the doped film. In addition, n-doped LPPV (23)e xhibited unprecedented air stabilityo fn -type polymer thermoelectric materials,o wing to the low LUMO level and especially strong interchain interactions, which could preventt he infiltration of H 2 Oa nd O 2 .T his strategy of conformation control could enhance not only intrachain carrier transfer properties but also interchain packing, further influencing interchain charge transfer and stability.…”