Probably Not Another Replacement for Indium Tin Oxide (ITO)

Sometimes it seems that people who write about replacements for Indium Tin Oxide (ITO) can make more money than anyone actually trying to produce the stuff. While everyone gets excited for a week, let me try to be rational.

Since the dawn of nanotechnology, every year without fail someone has announced that they have found a way of using carbon nanotubes to replace the thin conducting film familiar (at least by function if not appearance) to users of any touch screen device, and without fail that’s the last we ever hear about it and plenty of companies who have worked on CNT based replecements have gone under after underestimating the technical challenges.

It’s a tough nut to crack. It will be done but it will take time as ITO is a wonderful material being both conductive AND transparent AND an industry standard with huge numbers of processes already designed around it. Many of the ITO replacements lack the required conductivity, and increasing the loading of nanotubes decreases the transparency giving an almost insoluble problem. Ideally you would want of mesh of almost one-dimensional nanotubes, but in practice dispersing the material in such a way that all the conducting nanotubes link up to provide a high conductivity is very difficult. So even if we could produce nanotubes cheaply enough to compete with ITO, dispersion and formulation remains a challenge.

But the problem is not just a technical one. ITO has been the industry standard for twenty years, and the process of depositing it on a wide variety of substrates is very well understood. Until the replacement is both significantly cheaper and performs better there is little incentive to switch, even if you can integrate it with current production processes. Even rising Indium prices are simply passed on down the supply chain at present with little resistance.

Perhaps the biggest problem is our failure to break out of the thinking that innovation is linear, i.e. that things just get faster/smaller/cheaper and instead of thinking about replacing existing products we should be looking at displacing them.


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