Energy harvesting and temperature sensing thermoelectric devices based on the carbon template method.

A series of self‐supporting carbon nanomaterial films with different morphologies were employed as conductive templates for n‐junction after polyethyleneimine (PEI) doping by taking advantages of the entanglement between carbon nanotubes. With the assistance of dimethyl sulfoxide (DMSO)‐treated poly(3,4‐ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) films as p‐junction, flexible and light‐weight thermoelectric generators (TEGs) were assembled. The effect of the morphology of the carbon nanomaterial, including multi‐walled carbon nanotube (MWCNT), whisker carbon nanotube (WSCNT), and graphene on the electrical conductivity, mechanical properties and morphology of n‐junction was investigated, on basis of which thermoelectric properties of TEG were evaluated. The properties of the three carbon‐based self‐supporting films show significant differences. The MWCNT/PEI film exhibits a tensile strength of up to 36.23 ± 0.57 MPa due to the high entanglement network density of MWCNT. The entanglement of WSCNT/MWCNT/PEI provides an ideal conductive template for PEI to prepare n‐junction material. TEGs with PEDOT:PSS‐DMSO and WSCNT/MWCNT/PEI as p‐ and n‐junctions show high power generation performance and cyclability. The output power density is up to 4.6 nW/cm2 at ΔT = 42.0 K, matched to a suitable load. With its fast response and slow recovery, this TEG is expected to be used for human health monitoring and energy storage. [ABSTRACT FROM AUTHOR]