Warwick University scientists have unveiled a new method for patterning metals used in electronics and solar cells.
The new process creates patterned films of silver and copper using cheap organofluorine compounds.
Silver and copper are the most widely used electrical conductors in modern electronics and solar cells.
Conventional methods used to pattern these metals make the desired pattern of conducting lines by selectively removing metal from a film with the help of harmful chemicals, or by printing with costly metal inks.
The Warwick process ensures that there is no metal waste or toxic chemicals used, and the fabrication method is also compatible with continuous roll-to-roll processing.
Dr Ross Hatton and Dr Silvia Varagnolo were responsible for discovering that silver and copper do not condense onto extremely thin films of certain highly fluorinated organic compounds when the metal is deposited by simple thermal evaporation.
Thermal evaporation is already widely used on a large scale to make the thin metal film on the inside of crisp packets, and organofluorine compounds are already common place as the basis of non-stick cooking pans.
The researchers have shown that the organofluorine layer need only be 10 billionths of a meter thick to be effective, and so only tiny amounts are needed.
This unconventional approach also leaves the metal surface uncontaminated, which Hatton believes will be particularly important for the next generation sensors.
Sensors often require uncontaminated patterned films of these metals as platforms onto which sensing molecules can be attached.
Hatton and his team have also used their method to fabricate semi-transparent organic solar cells in which the top silver electrode is patterned with millions of tiny apertures per square centimeter.
This novel patterning cannot be achieved by any other scalable means directly on top of an organic electronic device.
Image and content: University of Warwick