Lightweight and Bulk Organic Thermoelectric Generators Employing Novel P-Type Few-Layered Graphene Nanoflakes

Abstract

Graphene exhibits both high electrical conductivity and large elastic modulus, which makes it an ideal material candidate for many electronic devices. At present not much work has been conducted on using graphene to construct thermoelectric devices, particularly due to its high thermal conductivity and lack of bulk fabrication. Films of graphene-based materials, however, and their nanocomposites have been shown to be promising candidates for thermoelectric energy generation. Exploring methods to enhance the thermoelectric performance of graphene and produce bulk samples can significantly widen its application in thermoelectrics. Realization of bulk organic materials in the thermoelectric community is highly desired to develop cheap, Earth-Abundant, light, and non-toxic thermoelectric generators. In this context, this work reports a new approach using pressed pellets bars of few layered graphene (FLG) nanoflakes employed in thermoelectric generators (TEGs). Firstly, FLG nano-flakes were produced by a novel dry physical grinding technique followed by graphene nano-flakes liberation using plasma treatment. The resultant material is highly pure with very low defects, possessing 3 to 5-layers stack as proved by Raman spectroscopy, X-ray diffraction measurement and scanning electron microscopy. The thermal and electronic properties confirm the anisotropy of the material and hence the varied performance characteristics parallel to and perpendicular to the pressing direction of the pellets. The full thermoelectric properties were characterized both parallel and perpendicular to the pressing direction, and the proof of concept thermoelectric generators were fabricated with variable amounts of legs.

Paper Thermoelectrics by a Solvent-Free Drawing Method of All Carbon-Based Materials

“…The utilized FLG was sourced from a novel dry physical grinding technique followed by graphene nanoflakes liberation using plasma treatment and intercalation with dielectric barrier discharge (DBD) utilizing both atmospheric and vacuum process. Most importantly, our synthesized FLG possessed significantly lower κ compared to other values reported for FLG, , which makes it suitable for thermoelectric applications. In addition, HB pencil traces comprise nanocomposites of graphite nanoparticles and multilayer sheets of graphene and clay .…”

Wearable Thermoelectric Materials and Devices for Self‐Powered Electronic Systems

“…Although the above theoretically calculated results show high ZT values and power factors for graphene, few experimental studies have explored the TE properties of graphene to date due to its super-high thermal conductivity, zero bandgap, and very high electron mobility. Li et al [136] proposed an approach that uses pressed pellets bars of few-layered graphene nanoflakes employed in TEGs. The nanoflakes were first produced by a novel, dry physical grinding technique and then liberated using plasma treatment.…”

“…Li et al. [ 136 ] proposed an approach that uses pressed pellets bars of few‐layered graphene nanoflakes employed in TEGs. The nanoflakes were first produced by a novel, dry physical grinding technique and then liberated using plasma treatment.…”

Sensors-on-paper: Fabrication of graphite thermal sensor arrays on cellulose paper for large area temperature mapping

“…Therefore, the current thermoelectric research is focused on finding low-cost and non-toxic thermoelectric conductors for the application [29] , [30] , [31] , [32] , [33] , [34] , [35] , [36] , [37] . With some improvements and modifications in the thermoelectric properties of graphite such as by organic doping or alloying with other semiconductors, they can also be utilized in the fabrication of thermoelectric devices [19] , [38] , [39] , [40] , [41] , [42] , [43] , [44] , [45] .…”