Prevailing modes of the manufacture of modern energy-harvesting systems and other electronics based on silicon fail to meet the requirements of the steps involved in low-cost fabrication. Rapid and low-cost roll-to-roll manufacture - the future of commercialization for flexible and printed electronics - requires flexible and lowcost substrates such as polyethylene terephthalate, polyethylene naphthalate and, more recently, green materials such as nano-paper. The temperature at every single fabrication stage is crucial with such materials and cannot exceed a certain threshold, generally 150 °C or less. Low-temperature plasma, therefore can provide an excellent way forward for future manufacturing methods. This contribution presents a proprietary, large-area plasma of extremely high-volume power density, up to 100 W/cm3, capable of generating diffuse, homogeneous and cold plasma (less than 70 °C) in the open air, as well as in technical-grade gases including nitrogen, argon, methane, hydrogen, carbon dioxide and pure water vapour. Although the temperature of the plasma is very low, the population of energetic states is sufficient to induce physical/chemical changes on the surfaces of a range of nanostructured materials and semiconductors, such as graphene oxide, titanium dioxide, perovskites, and others, resulting in various changes to crystallinity, optoelectronic, and wettability properties depending on the gas employed for plasma generation. The low temperature of the plasma and rapid treatment times, in the order of 1-10s, enables the integration of plasma processing into roll-to-roll manufacture, a significant step forward in commercial viability within the emerging field of flexible and printed electronics. This study provides an example of rapid (less than 1 min) low-temperature plasma processing of indium-tin-oxide electrodes as a replacement for time-consuming chemical treatment before deposition of PEDOT:PSS in a p-i-n perovskite solar cell.