Just in case you thought innovation was done in solar…

NovaSolix is a silicon valley startup developing a process to manufacture solar panels that use carbon nanotubes as antennas – combined with nanoscale rectifiers – to generate power from a much broader swath of the solar energy spectrum than conventional PV cells. The company claims that 80-90% efficiency may be possible. They are also working to develop a process to manufacture the panels on a substrate of glass, thus dramatically reducing the cost compared with silicon-based PV technology.
If the company is successful in hitting their efficiency and cost targets, they could quite literally change the world. The economics and practicality of solar versus other forms of energy is already at a tipping point, so tiny changes in the cost-per-watt of deploying solar can have massive effects on the economics of energy. Changes of the magnitude NovaSolix envisions could slam a brick on that balance scale, completely transforming the energy landscape (and wiping out entire major industries in the process).
In order to harness the full spectrum of visible and infrared light, we need antennas of varying lengths. NovaSolix is working to create just the right mix of manufacturing variation in their carbon nanotubes to give the optimal distribution of antenna lengths. The carbon nanotube antennas are “grown” between electrical contacts, and they create diodes at the interface point. Each successful nanotube pair creates an antenna and a full-wave rectifier. NovaSolix has now successfully created demo wafers, and the IV curve of the resulting devices is interesting. Conventional PV cells have a fairly flat IV curve, with current remaining relatively constant and voltage increasing proportional to output. The nanotube antennas, however, produce a more linear IV curve, which should allow for a simpler controller than conventional PV cells, as well as greater immunity to partial shading effects.
NovaSolix is currently doing wafer fabrication in the Stanford Nanofabrication Facility and growing carbon nanotubes in their own labs. Their plan is to work toward a small-volume production capability with a “boutique” version of the technology aimed at specialty markets where power-per-area is the critical factor. This includes portable applications such as solar aircraft, wearables, and satellites. This production will be done using primarily older-generation semi-automated IC fabrication equipment. NovaSolix can see bringing the cost per watt down from $10 to around $1 with this approach.

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