Enhanced Joule heating performance of flexible transparent conductive double-walled carbon nanotube films on sparked Ag nanoparticles

Abstract

A hybrid flexible and transparent heater based on double-walled carbon nanotubes (DWCNTs) and silver nanoparticles (AgNPs) is fabricated on a polyethylene terephthalate substrate via facile spray-coating and spark-depositing techniques, respectively. The AgNPs are simply prepared by electrically sparking pure Ag wires in ambient environment with no vacuum system required. The optical, electrical and electrothermal properties of the hybrid AgNP/DWCNT and simple DWCNT film devices are investigated. The results show that the hybrid film heaters exhibit superior electrothermal performances to the DWCNT film heaters, as having higher maximum temperatures at the same applied voltages, as well as faster thermal heating and cooling responses. The simple DWCNT heater with optical transmittance of 72.7% at a wavelength of 550 nm reaches the maximum temperature of 95.0 °C, whereas the hybrid AgNP/DWCNT heater with optical transmittance of 64.0% reaches higher maximum temperature of 118.6 °C, as electrically supplied at 8 V. Furthermore, the mechanical flexibility of the hybrid and DWCNT film heaters is studied with different folding directions, and a little deviation in their electronic conduction is observed, while still performing good heating temperature after a bending test. This simple hybrid film heater demonstrates the efficient electrothermal performances, which can be utilized as a flexible and transparent heating device in various practical applications.