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The coating that makes iPhones touch sensitive is running out

No, iPhone screens are not magic. They are coated in a transparent material called indium tin oxide that senses when a finger makes contact.

ITO comes from the metal indium, which must be mined. Prices are rising as it becomes more scarce; the U.S. government estimates that from 2010 to 2011, the cost for indium rose by 25 percent. The world could run out altogether in the next decade.

To keep costs down, electronics manufacturers will need to look to alternative materials. At the Semicon West conference Wednesday in San Francisco, industry experts reported on potential alternatives such as carbon nanotubes and silver nanowires that could someday become the dominant touchscreen coating.

During his presentation, Nanotech Biomachines CEO and CTO Will Martinez presented the audience with a transparent sheet covered in graphene — an emerging material made of a one-atom-thick layer of carbon atoms. He bent it back and forth to demonstrate its flexibility.

“Try this with ITO and ITO would be filled with cracks,” he said.

Rahul Gupta, senior director of business development at Cambrios Technologies, touted the features of his company’s silver nanowires. Nanowires can be any length but are 10,000 times skinnier than a human hair.

Unlike many emerging materials, silver nanowires are already used in a few laptops, e-ink devices and smartphones. But while the materials are cheap, processing them is not. He showed that silver nanowires and metal mesh, another alternative, can hit a “sweet spot” for transparency and conductivity. Silver nanowires have already been tested in a bendable e-ink display, when a display was bent 100,000 times without an impact on performance.

“It’s rock solid, steady,” Gupta said.

Gupta said requirements are changing for touchscreen coatings. They must now rival or top ITO in transparency and conductivity, plus be flexible and able to conform to curved surfaces. Meeting those requirements will be especially important as manufacturers adapt materials to the coming wave of wearable electronics and even 3D TVs.

Demand for touch sensitive devices is growing quickly, meaning manufacturers are racing to produce widely adopted ITO alternatives within the next few years. According to Cambrios, 1.4 billion smartphones will have touchscreens, compared to 531.9 million today. While far fewer laptops will have touchscreens, the demand for laptop touchscreens measured in square meters will soon rival phones. There will be 20 million square meters of laptop touchscreens by 2015, compared to 35 million square meters on phones.

Some manufacturers are already planning on incorporating ITO alternatives into their devices. Foxconn might begin using carbon nanotubes in the non-Apple devices it makes by the end of 2013, and Samsung is working on prototypes that use graphene, according to Martinez.

“There’s lots of R&D to be done though,” Martinez said.

This story was updated at 12:40 a.m. on July 12 to remove the word “metal” from the title. While the coating is partially made from metal, it is not itself a metal.

16 Responses to “The coating that makes iPhones touch sensitive is running out”

  1. Rick Short

    Additionally, indium is extremely recyclable – and recycled. According to SMG Indium Resources Ltd, “The recycling of indium has increased in recent years. The indium recycling market is now larger than primary refinery production”. In other words, more than half of the indium consumed comes from the recycling channel.

  2. Full disclosure: I work at The Indium Corporation (

    The following is offered in a constructive and collegial manner. Additional facts are welcomed.

    The above article is built upon numerous errors, and the conclusion is misleading.
    However, there is some correct information included. Let’s explore.

    #1: ITO is a ceramic, not a metal. Touchscreens are not coated with metal and wouldn’t work if they were.
    Some ingredients of ITO, indium and tin, are metals, but the coating is a semiconductor.

    #2: Indium prices do rise … and fall. Indium is a commodity and is traded in public markets. Additionally, as a natural material, indium’s current and perceived future value helps drive its “desirability” to companies who would extract and refine it. Accordingly, as prices rise, companies are financially encouraged to invest in obtaining indium to sell. As prices fall, companies are disincentivized to refine and offer indium – just like any other material. This is a classic economic cycle which affects most commodities (think milk, nurses, corn, oil, engineering graduates, etc.).

    #3: Indium is approximately three times more abundant in the earth’s crust than silver, according to the US Geologic Survey. And silver is extracted at 60x the rate of indium. Indium is certainly more complicated to isolate, refine, and bring to market than silver, and is priced accordingly – while normal market conditions operate. Our company’s research and analyses indicate that indium will remain available for consumer product use for well over 100 years. Please study our report and those of the USGS and offer any corrections that you might have.

    #4: Indium-based displays are proven to be extremely flexible. Samsung demo’d an indium-based OLED this year at CES: And SONY demo’d a flexible OLED 6 years ago: As technologists know, “Indium tin oxide (ITO) is commonly used as the anode material in OLEDs. Watch these videos and shaer your thoughts on the flexibility demonstrated.

    It is unquestionable that emerging technologies, like silver nanowires and carbon nanotubes, are exciting and very promising. It is important, both technologically and ethically, to make comparisons and contrasts in the most informed, logical, and fair manners. You can learn more at And, if you want a totally independent view on this topic, please scan this article from Forbes, that begins with, “I’ve been alerted by Bishop Hill to a slightly silly piece at the BBC that claims that Apple and all other electronics companies are going to have terrible problems when indium runs out in 2017.”.

  3. The world is simply not running out of indium. That’s one of those ridiculous myths perpetrated by people with an agenda to sell something else. Indium is 3x as common in the earth’s crust as silver, but we extract silver at 60x the rate we extract indium. More than half the world’s indium comes from recycling and that percentage is actually rising….

  4. I would love to see if someone out there could manufacture a material of this resilience without having to mine natural resources. Perhaps with enough time and efforts invested a combination of recycled materials? While I know little about the ITO I feel like this should be more of a concern since the average person somewhere down the line will have to pay that much more for a product that delivers such an important feature. Knowing little to nothing about this and then being asked to pay more for it just doesn’t seem to fit together well for me. While I’m no expert, I can easily foresee this being the case if they cannot produce a similar result with minimal resource.

    …furthermore, I concur with Prasad. Why is Apple being the only mention here when other companies are also using this?

  5. Prasad Tiruvalluri

    I do not get it. Do all touch phones use it or not. If not, what are the others using and why is only iPhone using it and what is stopping Apple to switch to those processes once the ITO is exhausted. If ITO is the only option for touch screens, why is the headline about iPhone when it only makes about a quarter of all phones..