Semiconducting polymer contributes favorably to the Seebeck coefficient in multi-component, high-performance n-type thermoelectric nanocomposites

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2020-05, Vol.8 (19), p.9797-985
• Main Authors: Tang, Junhui, Chen, Ruisi, Chen, Lidong, Bazan, Guillermo C, Liang, Ziqi
• Format: Article
• Language: English
• Subjects: Electrical conductivity; Electrical resistivity; Formability; Materials selection; Molecular chains; N-type semiconductors; Nanocomposites; Polymers; Power factor; Seebeck effect; Thermal conductivity; Thermoelectric materials; Thin films
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/d0ta02388d

n-Type semiconducting polymers bearing high Seebeck coefficients ( S ) have been seldom employed in organic-inorganic thermoelectric nanocomposites (TENCs). Herein we illustrate how to exploit an n-type semiconducting polymer to fabricate TENCs comprising N2200 and metallic Co NWs, in which N2200 contributes significantly to the S of the TENCs. The TENCs exhibit a highest power factor (PF) of 288 μW m −1 K −2 at 80 wt% Co NWs. At a greater Co NW content, the organic/inorganic inter-connectivity deteriorates, owing to the rigid molecular chains of N2200, retarding the increase of electrical conductivity ( σ ) and also undermining the mechanical flexibility. Flexible n-type doped SWCNTs were therefore added to introduce additional conductive paths. At an optimal amount of SWCNTs (2 wt%), the σ increases to 1860 S cm −1 , whereas S remains at approximately −45 μV K −1 and the bendability is improved. The maximal PF and zT values of the resulting ternary TENC reach 483 μW m −1 K −2 and 0.18 at 380 K, respectively. By pairing with p-type PEDOT:PSS/SWCNT thin films, the 6-legged flexible TEG yields maximum output voltage and power of 9.80 mV and 3.72 μW, respectively, when Δ T = 50 K. This work manifests a new avenue to both highly efficient and bendable thermoelectric materials through the judicious choice of multiple blend components. n-Type Co NWs/N2200 TENCs yield a high S , mainly from the semiconducting polymer, yet σ is limited by poor connectivity between inorganic and organic domains. By adding flexible n-doped SWCNTs to yield more conductive paths, σ and mechanical bendability are greatly enhanced.