Ultrahigh electron emissive carbon nanotubes impregnated with subnano RuO2 clusters

Multi-wall carbon nanotubes (MWNTs) have a great commercial potential as electron field emitters but suffer from fundamental problems such as poor stability and lack of brightness. Here we show that the MWNTs impregnated with nano and subnano-sized ruthenium dioxide (RuO₂) particles produce a new and high performance emitter. RuO₂ impregnation to carbon nanotubes (CNTs) was conducted by utilizing ruthenium tetraoxide (RuO₄) in air at ambient temperature and pressure. Compared to MWNTs without impregnation treatment, those CNTs impregnated with RuO₂ have superior and more efficient electrical characteristics with stable emission at a lower electric field. The RuO₂/MWNTs developed here can be applied to the field emission displays (FEDs) as the flat panel displays.