writer：Yi Li, Duo Jiang, Zan Li, Zhaohua Yang, Ping Fu, Yunfei Zhang *, Feipeng Du *
keywords：g-C3N4, Single-walled carbon nanotubes, Composite film, Thermoelectric properties, Interfacial interaction
source：期刊
specific source：Diamond & Related Materials
Issue time：2023年

Thermoelectric (TE) devices consisting of p-type and n-type single-walled carbon nanotubes (SWCNTs) based films, which can gather waste heat and turn it into electrical power, show potential application in supplying power for wearable electronic devices. In this study, graphitic carbon nitride (g-C3N4) has been prepared by high temperature pyrolysis of melamine and confirmed by scanning electron microscopy (SEM), transmission electron microscopy  (TEM),  Fourier  transform  infrared  spectroscopy  (FTIR),  and  X-ray  diffraction  pattern  (XRD), respectively. Then the prepared g-C3N4 is composited with SWCNTs via mechanical mixing and vacuum-filtering method to obtain free-standing flexible g-C3N4/SWCNT thermoelectric composite films. The results demonstrate that g-C3N4 is efficiently covered on the surface of SWCNTs via interfacial π-π interaction, and g-C3N4 layer with several nanometers coated on SWCNTs simultaneously improves the electrical conductivity (σ) and the Seebeck coefficient (S) of g-C3N4/SWCNT. At a mass ratio of 2.5 % for g-C3N4/SWCNT, an optimal power factor value of 163.0 ± 1.0 μW m^-1 K^-2 at room temperature. Finally, a self-powering TE device composed of three pairs of p-n junctions is manufactured, and the actual output power is about 1.13 μW at the temperature difference of 50 K. As a result, this  study  offers  a  straightforward  way  to  enhance  the  thermoelectric  performance  of  single-walled  carbon nanotubes, which can be utilized in flexible power generators.