Sintered device

A method for the production of an inorganic film on a substrate, the method comprising:

• (a) depositing a layer of nanoparticles on the substrate by contacting the substrate with a nanoparticle dispersion;
• (b) treating the deposited layer of nanoparticles to prevent removal of the nanoparticles in subsequent layer depositing steps;
• (c) depositing a further layer of nanoparticles onto the preceding nanoparticle layer on the substrate;
• (d) repeating treatment step (b) and deposition step (c) at least one further time;
• and
• (e) optionally thermally annealing the multilayer film produced following steps (a) to (d);
• wherein the method comprises at least one thermal annealing step in which the layer or layers of nanoparticles are thermally annealed to provide sintering between nanoparticles in adjacent layers of the film.