To enhance the electrical conductivity of the electrolyte for a newly developed dye-sensitized solar cell (DSSC), metallic copper (Cu) encapsulated within the carbon shell ([email protected]) nanoparticles dispersed in a room temperature ionic liquid (RTIL) (e.g., [ b m i m + ][ P F 6 − ]) has been studied in the present work. By the pulsed-field gradient spin-echo NMR method, the self-diffusion coefficients of cations and anions of the RTIL have been determined. The self-diffusion coefficient of the [ b m i m + ] cations in the RTIL dispersed with 0.08% of [email protected] nanoparticles is increased by 35%. The electrical conductivity of the [email protected] dispersed RTIL is also increased by 65% (1.0 → 2.3 ms/cm). It is very clear the nanosize [email protected] dispersed RTIL with a relatively greater diffusion coefficient and electrical conductivity can be a very effective electrolyte especially utilized in DSSCs.