The invention provides a method of forming a layer on a polymer substrate comprises a polymer substrate with at least one precursor, and applying ultraviolet light to decompose the at least one precursor and deposit a layer onto the polymer substrate. Also provided is a doped layer comprising zinc oxide deposited on a polymer substrate obtained by introducing at least one precursor comprising zinc and a dopant into a vessel containing a polymer substrate, and applying an ultraviolet light to decompose the at least one precursor and to deposit a layer comprising doped zinc oxide onto the polymer substrate.
