Abstract
The long-term stability of multi-wall carbon nanotubes (MWCNT) mixed with the hole-transport polymer Poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) has been examined. These surfactant stabilised solutions, used as transport layers in organic light emitting diodes (OLEDs), are shown to be stable for periods of up to fifteen months, and show no signs of degrading soon after this time. In comparison, non-stabilised aqueous MWCNT solutions have been shown to aggregate within 30 minutes of production, and, although these aggregates can be re-dispersed, the solution displays an increase in smaller aggregates over time which cannot subsequently be re-dispersed by manual agitation. The stable MWCNT/PEDOT:PSS solutions have been used in ink-jet printing and as composite MWCNT/PEDOT:PSS films suitable as charge transport layers in spin coated organic light emitting diodes.