Scalable fabrication of ultrahigh-conductivity SWCNT films via aredispersion method for photovoltaic/thermoelectric coupling systems

Photovoltaic/thermoelectric (PV/TE) coupling systems simultaneously cool solarcells and recover waste heat. Single-wall carbon nanotubes (SWCNTs) films areexpected to simultaneously exhibit their electrical conductivity, thermalconductivity, and thermoelectric properties in this application. FabricatingSWCNTs films with polymer-dispersed SWCNTs are simple, safe, and scalable.However, the difficulty in simultaneously enhancing both dispersion quality andSWCNT concentration significantly limit the electrical conductivity of thesefilms. Herein, we develop a SWCNT redispersion method in Nafion ethanol systemto achieve well-dispersion at high SWCNT concentrations. Using this dispersion,A4-sized films were readily prepared, achieving remarkable electricalconductivity of 1.97 MS/m. The large-area film exhibits a high power factor(654.37 μW/(m·K²)) and apparent thermal conductivity (529 W/(m·K)),and is integrated into a 330 cm² thermoelectric/photovoltaic couplingsystem. The PV output power increases by 220 mW. An additional 70 mVthermoelectric voltage is generated. Moreover, the investigation of the dryingprocess unravels how polymer, solvent and SWCNT concentration collectivelydominate the film uniformity. This work significantly enhances the electricalconductivity of polymer-dispersed SWCNTs and explores an application directionthat simultaneously utilizes their high thermoelectric performance and thermalconductivity, highlighting their great application potential in PV/TE systems.