High thermoelectric figure of merit in nanocrystalline polyaniline at low temperatures

Abstract

Thermoelectric coolers with figure of merit (ZT) close to unity at low temperatures are the need of the hour with new advances in high temperature superconductors, superconducting microelectronic circuits, quantum computers, and photonics. Here, we demonstrate that the conducting polymer polyaniline (Pani) doped with camphor sulfonic acid synthesized in semi-crystalline nanostructures, possesses a giant Seebeck effect at low temperatures. The resulting enormously large Seebeck coefficient (up to 0.6 V/K) combined with an intrinsically low electrical conductivity and thermal conductivity give rise to a ZT = 0.77 at 45 K and ZT = 2.17 at 17 K.

Flexible Thermoelectric Materials and Generators: Challenges and Innovations

“…Figure a shows several representative molecular structures of conductive polymers, including p‐type PANI, P3HT, P3BT, PA, PEDOT, PTs, and PPy; n‐type polybenzimidazobenzophenanthroline (BBL), poly[K x (Ni‐ett)], poly(perinaphthalene) (PPN), and poly(Cu‐benzenehexathiol) (CuBHT) . Unlike saturated insulating polymers whose carbon atoms are sp 3 hybridized and all electrons are localized in the form of covalent bonding, conductive polymers have backbones of contiguous sp 2 hybridized carbon centers with delocalized electrons .…”

“…Current studies on FTEs mainly focus on two aspects of these materials: 1) the development of high‐performance FTE materials, and 2) the fabrication of high‐output FTE devices through rational design . In terms of material development, one strategy is to utilize conductive polymers, including poly(3,4‐ethylenedioxythiophene) (PEDOT), poly(3‐hexylthiophene‐2,5‐diyl) (P3HT), poly(3‐butylthiophene) (P3BT), polyaniline (PANI), polyacetylene (PA), polypyrrole (PPy), and polythiophenes (PTs), due to their intrinsic flexibility and conductivity . Additionally, conductive polymers are abundant, nontoxic or low‐toxicity, and generally easy to shape and process for industrial applications .…”

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

“…Moreover, the three triblock copolymers have similar XRD patterns and show a wide peak at 2θ = 19.7° (equal to d‐spacing of 4.4 Å calculated with Bragg's law), which is ascribed to the periodicity parallel to the aniline oligomers segments . The ordered stacking of aniline units can promote the electronic coupling between the π electrons of adjacent aniline units, which is essential for the formation of interchain electronic band and efficient charge transport …”

A Comparative Study of Potentiodynamic and Potentiostatic Modes in the Deposition of Polyaniline

“…The peak at 2θ = 21.28 corresponds to (1 0 0) reflections, which is ascribed to a periodicity parallel to the polymer chains. 32 Compared to the PAni formed under PSM, the increased intensity of this peak in the PAni grown by PDM implies improved interchain π-π stacking. 33 The peak at 2θ = 25.20 corresponds to (1 1 0) reflections, which is associated with a periodicity perpendicular to the polymer chains.…”

“…32 In the PAni formed under PSM, the relative intensities of the peaks at 2θ = 16.48 and 21.28 decrease and become nearly indistinguishable from the background, indicative of crystalline (ordered) regions dispersed in an amorphous structure. The peak at 2θ = 21.28 corresponds to (1 0 0) reflections, which is ascribed to a periodicity parallel to the polymer chains.…”