Thermoelectric and Photothermoelectric Properties of Nanocomposite Films Based on Polybenzimidazole and Carbon Nanotubes

We herein report the thermoelectric and photothermoelectric properties of polybenzimidazole (PBI)-based nanocomposite films with 1-20 wt % multiwalled carbon nanotube (MWCNT) loadings, which are manufactured by a facile solution casting method. The thermoelectric characterization, which is carried out at temperature differences of up to 40 K between both film ends, reveals that the Seebeck coefficient of the nanocomposite films increases from similar to 29 to similar to 36 mu V/K with increasing MWCNT content from 1 to 20 wt % and that the thermoelectric current generation efficiency changes from similar to 1 nA/K at 1 wt % MWCNT to similar to 84 nA/K at 10 wt % MWCNT to similar to 28 nA/K at 20 wt % MWCNT. The visible light illumination at the interface between the nanocomposite film and the silver electrode induces excellent photothermoelectric performance in terms of temperature increment (Delta T-PT), voltage generation (V-PTE), and electric current generation (A(PTE)), which are dependent on the MWCNT content and visible light wavelength. For instance, the PBI nanocomposite film with 10 wt % MWCNT can attain Delta T-PT of similar to 33 degrees C, V-PTE of similar to 267 mu V, and A(PTE) of similar to 234 nA under the visible light illumination of 520 nm wavelength and 8.87 W/cm(2) power density at the interface between the film and the electrode. This excellent photothermoelectric performance of PBI/MWCNT nanocomposite films enables potential materials for advanced applications of energy harvesting and sensing from visible light and heat.

Automated summary

In this study, the thermoelectric and photothermoelectric properties of PBI-based nanocomposite films with different loadings of MWCNT were investigated. The results showed that the Seebeck coefficient and thermoelectric current generation efficiency of the nanocomposite films increased with the increase of MWCNT content. In addition, visible light illumination at the interface between the film and electrode induced excellent photothermoelectric performance.