Self-Standing and Flexible Thermoelectric Nanofiber Mat of an n-Type Conjugated Polymer

Abstract

The intrinsic flexibility makes conjugated polymers an ideal choice for wearable thermoelectrics. The n-type polymer thermoelectric is still in its infancy. The majority of research on the n-type polymer thermoelectric focuses on the design of n-type conjugated polymers and high-efficiency n-dopants. In this paper, we report a self-standing and flexible nanofiber mat of an n-type conjugate polymer prepared with electrospinning technology. We choose a representative n-type conjugate polymer N2200. The electrospun N2200 nanofiber mat shows a maximal conductivity of 7.06 × 10–4 S/cm, a maximal Seebeck coefficient of −346 μV/K, and a maximal power factor of 0.0085 μW/(m K2). This thermoelectric performance is fairly comparable to that of the traditional spin-coated N2200 thin film. The nanofiber mat is self-standing, flexible, and stretchable and thus can attach to human skin and move with body movement. This work demonstrates the feasibility of fabricating flexible thermoelectric devices by an electrospinning technique and lays a foundation for the applications of n-type conjugated polymers in wearable electronics.

Soft Fiber Electronics Based on Semiconducting Polymer

“…Li et al prepared nanofibers of n-type semiconducting polymers poly{[N,N′-bis(2-octyldodecyl) naphthalene-1,4,5,8-bis (dicarboximide)-2,6-diyl]-alt-5,5′-(2,2′-bithiophene)} (P(NDI2OD-T2)) by the electrospinning technique and employed them in wearable TE applications (Figure 27c). 627 It exhibited excellent electrical properties with a maximum conductivity of 7.06 × 10 −4 S cm −1 , a maximum Seebeck coefficient of −346 μV K −1 , and a maximum power factor of 0.0085 μW m −1 K −2 . Chen et al prepared poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(bithiophene)] (F8T2) nanofibers with diameters <300 nm using electrospinning with xylene and chloroform as cosolvents.…”

“…(c) Preparation method and morphology of N2200 TE nanofiber mats by electrospinning. Reproduced with permission from ref . Copyright 2021 American Chemical Society.…”

“…The use of electrospun P3HT fibers in FETs resulted in hole mobility of 0.03 cm 2 V –1 S –1 and a current on/off ratio of 10 3 . Li et al prepared nanofibers of n-type semiconducting polymers poly­{[ N , N ′-bis­(2-octyldodecyl) naphthalene-1,4,5,8-bis (dicarboximide)-2,6-diyl]- alt -5,5′-(2,2′-bithiophene)} (P­(NDI2OD-T2)) by the electrospinning technique and employed them in wearable TE applications (Figure c) . It exhibited excellent electrical properties with a maximum conductivity of 7.06 × 10 –4 S cm –1 , a maximum Seebeck coefficient of −346 μV K –1 , and a maximum power factor of 0.0085 μW m –1 K –2 .…”

Advances in Ionic Thermoelectrics: From Materials to Devices

“…The self‐healing abilities can be achieved by the dynamic breaking and reform of conjugate bond stackings, electrostatic attractions, hydrogen bonds. [ 94,125 ] As illustrated in Figure 11 a, freestanding ternary hybrids of PANI, PAAMPSA, and PA conceive the reversibility of electrostatic interactions and hydrogen bonds. The shaped composite film exhibits autonomous self‐recovery ability without any external motivation such as pressure, wave, or heat.…”

Synthesis and living crystallization-driven self-assembly of backbone asymmetric and symmetric π-conjugated oligo(p-phenylene ethynylene)-based block copolymers

“…π-Conjugated-polymer-based nanofibers (CPNFs) have attracted increasing attention owing to their inherent electronic and photophysical properties and special morphologydependent properties. [1][2][3][4][5][6][7][8][9] Solution self-assembly of π-conjugated-polymer-based amphiphilic diblock copolymers (BCPs) in selective solvents has been explored as a robust route to generate nanostructures of various morphologies and compositions. [10][11][12][13][14][15][16][17][18] Nevertheless, it remains a challenge to create CPNFs with high morphological purity and precise dimensions and composition.…”