A multi-wall carbon nanotube/polymethyl methacrylate composite for use in field emitters on flexible substrates

A polymer-based multi-walled carbon nanotube (MWCNT) field emission device was fabricated from a mixture of dispersed MWCNTs and an aqueous solution of polymethyl methacrylate (PMMA). When the mixture was applied to a substrate, the PMMA formed a strong composite with the MWCNTs, while strongly binding to the substrate. Process optimization was carried out to obtain high field emission performance by controlling the density of the MWCNT emitter tips under good adhesion conditions. The polymer concentration in the MWCNT dispersion and the number of spray coatings of the solution on the substrate served as the variables. The optimized polymer-based MWCNT field emission device showed a low turn-on field of 1.07 V/μm, a high electric field enhancement factor of 2450, highly uniform emission, and long-term stability. The successful application of the developed emitters to a flexible polymer polyethylene terephthalate (PET) substrate was accomplished with good emission uniformity and long stability.