A gold nanodot array imprinting process based on solid-state dewetting for efficient oxide-free photovoltaic devices

We report the development of an efficient imprinting process for the formation of metal (Au) nanodot arrays using a square-patterned medium substrate. Solid-state dewetting is induced by differences in the surface energy of the metal film and the interface energy between the substrate and the metal film. Thus, uniform metal nanodot arrays were transferred to the desired substrate by controlling the interfacial surface free energy between the metal film and the substrate. Optical extinction measurements showed an intense extinction peak at 550 nm, corresponding to the simulated result. Imprinting of the Au-nanodot arrays on the substrate enhanced the light trapping function and supported the electrical properties of a polymer electrode. In addition, the combination of a transparent conducting oxide-free device with the Au-nanodot arrays and a polymer electrode resulted in enhanced performance. This can be attributed to the fact that the Au-nanodot arrays allowed higher charge extraction, as confirmed by electrical analyses. Finally, a next-generation approach of imprinting metal nanodot arrays was introduced through the controlled solid-state dewetting mechanism in a specific area, which can be applicable not only in the development of optoelectronic devices but also in semiconductor processes requiring metal nanostructures.