Influence of microstructure and thermoelectric properties on the power density of multi-walled carbon nanotube/ metal oxide hybrid flexible thermoelectric generators

The quest for a low-cost, flexible thermoelectric generator using eco-friendly metal oxide-based materials for low-temperature applications has motivated this work. The work compares the performance of amine-functionalized multi-walled carbon nanotubes (MWCNT-NH2) and metal oxide nanoparticles (CuO, NiO, and Fe2O3) ink-based hybrid flexible thermoelectric generators. Study reveals that the thermoelectric performance of a flexible thermoelectric generator improves by fine-tuning the materials crystallite size, bandgap, carrier concentration, carrier mobility, resistivity, the Seebeck coefficient, and micro-porosity of the ink film, which could be materialized by using hybrid thermoelectric materials. Among the three fabricated devices, MWCNT-NH2/NiO hybrid flexible thermoelectric generator exhibits a maximum power output of 1.44 nW at ΔT= 100 °C. The maximum power density displayed by MWCNT-NH2/NiO hybrid device is 59.3 nW/cm2 at ΔT= 100 °C, which is 23.28% and 332.8% higher than that of MWCNT-NH2/CuO and MWCNT-NH2/Fe2O3-based devices, respectively. The performance of MWCNT-NH2/NiO is comparatively superior to some previously reported works.