A method of forming a film of lanthanide oxide nanoparticles. In one embodiment of the present invention, the method includes the steps of: (a) providing a first substrate with a conducting surface and a second substrate that is positioned apart from the first substrate, (b) applying a voltage between the first substrate and the second substrate, (c) immersing the first substrate and the second substrate in a solution that comprises a plurality of lanthanide oxide nanoparticles suspended in a non-polar solvent or apolar solvent for a first duration of time effective to form a film of lanthanide oxide nanoparticles on the conducting surface of the first substrate, and (d) after the immersing step, removing the first substrate from the solution and exposing the first substrate to air while maintaining the applied voltage for a second duration of time to dry the film of lanthanide oxide nanoparticles formed on the conducting surface of the first substrate.