Monolithic Carbon Nanotube Film Thermoelectric Generator
Md. Nazibul Hasan, Asan G. A. Muthalif, Tanveer Saleh, Zhibin Zhang, Mohamed Sultan Mohamed Ali
Abstract
The design and development of a thermoelectric generator (TEG) with minimal internal resistance is crucial for achieving high output power in self-powered wearable technologies. This work presents a novel flexible TEG comprising single-walled carbon nanotube (SWCNT) thermoelements, fabricated through a sacrificial molding process. Different from the traditional TEG structural design, our TEG’s <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${p}$ </tex-math></inline-formula> - and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${n}$ </tex-math></inline-formula> -type SWCNT thermoelements are formed monolithically without any interconnections. This integration eliminates the presence of internal resistance within the device. Equipped with eight pairs of the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${p}$ </tex-math></inline-formula> - and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${n}$ </tex-math></inline-formula> -type SWCNT thermoelements, the TEG exhibits an open-circuit voltage ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{\text {oc}}{)}$ </tex-math></inline-formula> of ~21.82 mV and an internal resistance of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sim 16.56~\Omega $ </tex-math></inline-formula> , corresponding to a maximum output power of approximately <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$7.19~\mu \text{W}$ </tex-math></inline-formula> at a temperature gradient <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$(\Delta {T})$ </tex-math></inline-formula> of 50 °C. Additionally, the TEG demonstrated its capability to harvest energy from a fingertip, generating a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{\text {oc}}$ </tex-math></inline-formula> of around 2.58 mV at a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Delta {T}$ </tex-math></inline-formula> of 8.8 °C. These results highlight the potential of the monolithically formed SWCNT thermoelements for achieving high-power density TEGs.