With the introduction of Apple’s iPhone and then all the other smart phones, and then the introduction of Apple’s iPad followed by all the other tablets, touch screen displays have experienced enormous growth over the last six years. However, from the beginning of that growth, concern was developing about what could be done about the relatively scarce resource of indium-tin oxide (ITO) that these devices need to operate.
ITO is used as a transparent conductor to control display pixels. What was a clear challenge and concern for display manufacturers actually served as a new ray of hope for nanomaterial producers. Companies like Cambrios Technologies, which had been launched back in 2002 with the aim of getting man-made viruses to pattern inorganic materials for a host of electronic applications, finally saw an application that was driven by "market pull" rather than "technology push".
Cambrios now markets itself on its homepage as a leader in silver nanowire solutions for replacing ITO. While the technology is still described at times as “the use of genetically modified viruses to create transparent coatings made of silver nanowires for touch screen displays”, the genetically modified virus bit gets left off most of the marketing and instead is replaced with descriptions like this from the website: “Our proprietary nanostructured materials can be deposited using existing production equipment.” However it's marketed, Cambrios has become a player in the replacement of ITO with nanomaterials.
Cambrios is not alone as a provider of silver nanowire materials for replacing ITO, companies such as Blue Nano and Carestream Health are just a couple of the competitors offering this solution. But nanowire technology is not the only material that tackles the ITO replacement issue.
Cima Nanotech, which has spent the last 10 years in low-profile development of its self-assembling nanoparticle coating, announced earlier this year commercial-scale production of a transparent coating.
While Cima does have its coating technology already in commercial use for EMI shielding in laptops for rugged environments, I learned after speaking to the company’s CEO, Jon Brodd, that the firm is expecting to make announcements about some of the big display companies using their technology as an ITO replacement. A description of Cima’s self-assembling nanoparticle coating can be seen in the video below.
While nanowires and nanoparticles have gotten nearly a decade head start in becoming the much-needed ITO replacement, graphene is offering itself into this market, as well. Samsung has demonstrated a display based on graphene, but the material is still largely at a research stage at this point. While graphene does possess superior transmission performance characteristics over ITO and single-walled carbon nanotubes, less costly and more repeatable manufacturing process will need to be developed if it is really to compete in this marketplace.
One thing is for certain with all of these nanomaterial companies: selling a nanomaterial by itself is just not going to work. For a nanomaterial business to succeed it needs to develop the upstream product. It either can be a specially formulated emulsion used in the coating, or the coating itself, but it can be assured that selling only nanoparticles of any kind is largely a doomed business model.
It’s really difficult to say at this point which of these materials will be the ITO replacement of choice in touch screen displays. But one can say with some confidence that consumers will be getting a product with better performance and endurance characteristics at a likely lower price.
Photo: Merve Karahan/iStockphoto
Dexter Johnson is a contributing editor at IEEE Spectrum, with a focus on nanotechnology.
