their spectrum is fixed around a sort of yellowish white. “If you’d like more aquas or greens or reds, for example, you are out of luck,” he says.
Nanosys has a technology for making phosphors whose color output is much more tunable than YAG phosphors. By growing Indium phosphide nanocrystals or so-called “quantum dots” to precise sizes, the company can make phosphors whose emissions peak at any wavelength a manufacturer wants. “By combining different batches of colored phosphors together, we can even get multiple peaks, giving a customer exactly what he’s looking for in terms of red, green, and blue color characteristics,” Hartlove says.
The result is striking, as Hartlove demonstrated by showing me prototype phone and laptop screens illuminated by LEDs containing Nanosys phosphors (see the photo below; the Nanosys screen is on the lower left). Nanosys-powered screens have far richer reds and greens than their conventional counterparts. That’s a feature that could appeal both to consumers, who increasingly use their phones to take, browse, and share photographs, and to the design community, which depends on monitors with accurate color ranges to preview multimedia materials for print and digital distribution.
But Hartlove’s next trick was to actually get the Nanosys phosphors into such devices. He suspected the company would have difficulty selling the material directly to LED manufacturers. “The guys who really care about color are display manufacturers,” he says. “They needed a way to integrate it. What we came up with was a strip of material called a QuantumRail, a thin piece of material that contains quantum-dot phosphors formulated to their specifications.”
The Nanosys QuantumRail is definitely MacGyver-worthy: it’s designed to be glued to an existing screen component called the light guide, an optical panel that spreads light from LEDs evenly beneath an LCD screen. This way, display makers can continue to use plentiful blue LEDs to generate light, and simply tune the output wavelength by ordering customized QuantumRails.
Nanosys signed an agreement earlier this year with display manufacturer LG Innotek—a part of the giant LG electronics, chemicals, and telecommunications conglomerate—to supply millions of QuantumRails for cell phone displays. Hartlove says the company is also working with three makers of notebook computers to get QuantumRails into notebook displays, but that “we’re just a little further behind in the timeline in terms of getting these guys to production, since their product cycle only refreshes a couple of times a year.”
The second major business area where Hartlove felt Nanosys had a marketable technology—battery anode materials—is also some distance from production, since the battery industry moves even more slowly than the display industry. But in this area, Nanosys technology could ultimately have a far greater impact.
[This paragraph updated with corrected figures] On average, battery makers are able to increase the capacity of the rechargeable lithium-ion batteries that are ubiquitous in today’s mobile phones and laptops by about 6 or 7 percent per year, meaning capacity doubles every 12 years or so. One limitation on progress is the ability of the graphite typically used in battery anodes to absorb or “intercalate” lithium ions, which is what occurs when
