Transduction between electrical energy and the heat in a carbon nanotube using a voltage-controlled doping

TL;DR

This study demonstrates a significant transduction between heat and electrical energy in carbon nanotubes by voltage-controlled doping, achieving high efficiency and power density through suppression of thermal conductivity.

Contribution

It introduces a method to enhance energy transduction in CNTs by doping control, significantly reducing thermal conductivity and enabling high-performance heat-electrical conversion.

Findings

Effective electron temperature change of ~115 K observed.

Achieved figure of merit ZT ~ 6.

Transduced power density ~ 80 kW/cm².

Abstract

High electric conductivity ~100 MegaSiemens/m and Seebeck coefficient >200 mkV/K of carbon nanotubes (CNT) make them attractive for a variety of applications. Unfortunately, a high thermal conductivity ~ 3000 W/(m*K) due to the phonon transport limits their capability for transforming energy between the heat and electricity. Here we show that increasing the charge carrier concentrations not only leads to an increase of both electric conductivity and Seebeck coeffcient, but also causes a substantial suppression of the thermal conductivity due to intensifying the phonon-electron collisions. A strong transduction effect corresponding to an effective electron temperature change ~115 K was observed in a CNT device, where the local gate electrodes have controlled the charge doping in the opposite ends. Transduction between the heat and the energy of the electron subsystem corresponds to an impressive figure of merit cold ZT ~ 6 and the transduced power density P ~ 80kW/cm2.