Thermophotoinduced electron emission from conductive composite based on polytetrafluoroethylene with carbon nanotubes

This work explores the potential of conductive polymer-carbon nanocomposites, specifically polytetrafluoroethylene with multi-walled carbon nanotubes (PTFE-CNTs), as efficient electron emitters for emission electronics, low-temperature thermionic energy conversion (TEC), sensors, elements of information storage devices, and materials with targeted control of electromagnetic waves' absorption/reflection. Our main scientific contribution is the demonstration of electron emission from investigated composite PTFE + 10 wt% CNTs at significantly reduced operating temperatures (near 200 °C), much lower than those for pure CNTs and conventional materials for emission electronics and energy. The research combines experimental studies of electron emission under concentrated solar and pulsed laser radiation, structural characterization of samples by electron microscopy, and positron spectroscopy. The last method and contact potential difference method are used to investigate the electronic properties, including charge transfer between composite components, and the work function of the material. Results indicate that electrons can be emitted from both the surface and subsurface (through the polymer layer) of CNTs. The emission current can be enhanced by the Schottky effect due to the electrical fields of adsorbed cations. Additionally, a novel method for tuning the composite's work function due to irradiation by low-energy electrons is proposed. It opens pathways for targeted control not only of emission performance but other electronic properties of polymer-carbon nanocomposites, including absorption and reflection of electromagnetic waves in a wide frequency range.