Synthesis and Thermoelectric Properties of Polycarbazole, Polyindolocarbazole, and Polydiindolocarbazole Derivatives

Abstract

In a quest for thermoelectric polymeric materials novel polycarbazole and polyindolocarbazole derivatives were synthesized. Alkyl side chains on the carbazole cycle and different side chains (alkyl or benzoyl) on the nitrogen atom of the backbone unit were introduced. Optical, electrochemical, electrical, and thermoelectric properties were investigated on these polymers and on two poly(diindolocarbazole)s. Band structure calculations were used to predict which polymers might be promising as thermoelectric materials. The best combination of Seebeck coefficient and conductivity (power factor) was around 10 -7 Wm -1 K -2 with copolymers comprising thiophene units alternating with carbazole or indolocarbazole. This family of polymers possesses good Seebeck coefficients, but there is still a need to improve the electrical conductivity, to produce useful thermoelectric materials.

Syntheses and properties of copolymers containing indolocarbazole moiety in the side chain

“…16 In addition, there have also been some reports on polymers containing the INC moiety. [26][27][28][29] For example, Li et al 15 synthesized a new class of polyindolocarbazole via the coupling polymerization of 2,8-dichloroindolo [3,2-b]carbazole derivatives, a film of which could be manufactured by spin coating and exhibited a field-effect transistor mobility of 0.02 cm 2 V À1 s À1 . However, INC derivatives have drawbacks, including poor solubility in organic solvents and a lack of chemical stability.…”

Synthesis of Poly(2,7‐carbazole)s and Derivatives

“…In addition to the fine-tuning of the side chain on the nitrogen atom, several functional groups can be added at the 3,6-or 1,8-positions to avoid degradation, to improve the organization, or even to modify the optical properties of the synthesized oligomers or polymers. Functional groups such as halogen, alkyl, nitrile, nitro, ketone, or silane can easily be introduced onto the carbazole backbone [74,[79][80][81]. Finally, novel methodologies that can afford 2,7-functionalized carbazoles were obtained through modified Hartwig and Buchwald palladium cross-coupling reactions (Scheme 6.4) [82][83][84].…”

Two isostructural halogen derivatives of 9-ethylcarbazole: crystal structure, Hirshfeld surface analysis, and structural comparison with other simple analogs

“…Namely, materials based on them are very promising because of their great stability, good solubility, excellent photoconductive properties, relatively intense luminescence, and good performance in OFETs, OLEDs, and thermoelectric materials [42][43][44][45][46][47][48][49][50][51][52]. Moreover, these compounds, and particularly halogenated carbazoles, are important synthetic intermediates and pharmacological targets [53].…”