Thermally Sensitive N‐Type Thermoelectric Aniline Oligomer‐Block‐Polyethylene Glycol‐Block‐Aniline Oligomer ABA Triblock Copolymers

Abstract

High‐performance n‐type thermoelectric polymers are vital in the development of polymer thermoelectric generators (PTEGs). However, the progress is very slow due to their low stability and low thermoelectric properties. Here, aniline oligomer‐block‐polyethylene glycol‐block‐aniline oligomer (ANI)n‐b‐PEO‐b‐(ANI)n) (n = 4, 8, 16) are prepared and studied. The results indicate that the (ANI)n‐b‐PEO‐b‐(ANI)n show unique temperature sensitivity and switch from p‐type to n‐type when the temperature is above 300 K. Differential scanning calorimetry curves show that the Tg of the (ANI)n‐b‐PEO‐b‐(ANI)n is lower than 300 K, indicating that PEO segments of the (ANI)n‐b‐PEO‐b‐(ANI)n easily move above 300 K and have high flexibility. Temperature‐dependent Raman spectra confirm that there are strong interactions between PEO segments and aniline oligomers during the raising temperature, and PEO chains might provide plenty of negative charge at high temperature, which can convert the (ANI)n‐b‐PEO‐b‐(ANI)n into n‐type thermoelectric materials. To adjust the number of aniline unit, (ANI)8‐b‐PEO‐b‐(ANI)8 shows excellent n‐type characteristics with Seebeck coefficient as large as −1171 µV K−1 at 381 K. The strong interaction between PEO and aniline oligomers plays a dominant role in the n‐type thermoelectric performance of the triblock copolymers, which have potential application in the field of PTEGs and temperature sensors.

Modulating Carrier Type for Enhanced Thermoelectric Performance of Single-Walled Carbon Nanotubes/Polyethyleneimine Composites

“…The performance of TE materials is evaluated by a dimensionless figure of merit, ZT , through the equation ZT = S 2 σT ⁄ κ (where S is the Seebeck coefficient, σ is the electrical conductivity, κ is the thermal conductivity, and T is the absolute temperature), wherein S 2 σ is defined as power factor (PF) [4,5,6]. The Seebeck coefficient can be positive (holes, p -type) or negative (electron, n -type) depending on the main charge carrier type [7,8,9]. Inorganic semiconductors, such as Bi 2 Te 3 , PbTe, and Sb 2 Te 3 , are often used as TE materials due to their high ZT values.…”

Fabrication of Porous Polyvinylidene Fluoride/Multi-Walled Carbon Nanotube Nanocomposites and Their Enhanced Thermoelectric Performance

“…The thermal conductivity of conducting polymer ranges from 0.02 W·m −1 ·K −1 and 0.6 W·m −1 ·K −1 , which is far lower than those of conventional inorganic TE materials [3]. So far, the main conducting polymers that have been commonly used as organic thermoelectric materials include poly(3,4-ethylenedioxythiophene) (PEDOT), polypyrrole (PPy) and polyaniline (PANI) [4,5,6]. Notably, the thermoelectric performance of the polymer thermoelectric materials can be greatly enhanced though compositing with inorganic materials such as carbon nanotubes, graphene, silver nanowires, etc.…”