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ARPA-E award helps Berkeley Lab groups shine smart windows tech

Berkeley Lab researchers will use their new grant to perfect new thin-film and manufacturing technologies that will can deliver low-cost window coatings that can be switched reversibly through three states: fully transparent, visibly transparent while heat blocking and light and heat blocking. Credit: LBL.

A research group led by Delia Milliron at the Lawrence Berkeley National lab has been hammering away for several years to forge smart window technologies that can drive down the cost and address the practicalities involved with bringing such energy-saving materials in reach of consumers. Earlier this week, Milliron’s efforts were rewarded with a nice $3 million ARPA-E grant to further efforts to improve the performance and lower production costs for materials that will yield commercial electrochromic windows.

Which isn’t to say that smart window tech isn’t available to consumers. It is, for example, from Sage Electrochromics, whose flagship product, SageGlass, is being produced with a hefty investment from Saint-Gobain.

But Milliron’s group, part of LBL’s Molecular Foundry, along with the Berkeley Lab’s Environmental Energy Technologies Division, believes the currently line of commercial smart windows aren’t agile enough and are still too far from affordable for most applications.

I first came across LBL’s work in this area in 2010 when I wrote about the “Carbon Smackdown-Smart Windows video that featured Milliron and EETD colleague Stephen Selkowitz (coprincipal investigator on the ARPA-E project) presenting a really great overview of the smart windows field.

The premise, as I understand it, for the ARPA-E grant is that efficient smart windows must separate the filtering of visible light from the filtering of near-infrared radiation, i.e., a more-perfect conceptual engineering solution is to control heat transmission without interfering substantially with light transmission. Further, costs can be driven down by delivering the technology to the windowmaking industry in a way that efficiently uses current glassmaking techniques. According to Berkeley Lab press release, Milliron and Selkowitz believe their researchers have candidate nanocrystal thin films that can individually block the NIR and visible light components, and additionally have an inexpensive approach for applying the film that, according to ARPA-E, is similar to spray-painting a car.

These researchers and the Berkeley Lab had already spun off a company, Heliotrope Technologies, to work on commercial development of the electrochromic applications. Heliotrope has already gained recognition for its efforts, and in the lab’s press release, company CTO Guillermo Garcia, says the next goals are to perfect the solution processing of the nanocrystal films (which makes the idea of “spray-painting” possible) and improve the material’s functionality.

For more about Milliron and her group’s research into the above-mentioned electrochromic materials, see for example, “Tunable Infrared Absorption and Visible Transparency of Colloidal Aluminum-Doped Zinc Oxide Nanocrystals” that appeared in 2011 Nano Letters (doi:10.1021/nl203030f).