innovation: Article- Blacker Than Black

Nothing’s cooler than black—and nothing converts more of the sun’s energy into useable electric current. A cutting-edge technology called ENABLE, the focus of a new collaboration between Los Alamos National Laboratory and RoseStreet Labs Energy, Inc., targets converting more of the sun’s energy into usable electrical current than previously thought possible using a process that grows thin films the color of night.

“It’s possibly the blackest material I’ve ever seen simply because it absorbs so much light across a broad range of colors,” said Michael Erickson, business development and licensing executive for LANL’s technology transfer division, of ENABLE films.

Conventional solar technologies can efficiently capture only a portion of the solar spectrum to make usable current. Consequently, much of the available energy is lost as heat or transmitted through the cell, degrading the overall solar cell’s efficiency.

“RSLE’s product technology is focused on greatly enhancing the ability to absorb light, directly converting it into electricity and making possible more efficient solar energy generation,” said Bob Forcier, the company’s chief executive officer. “ENABLE processed films for RSLE products have initially demonstrated strong potential for enhancing our product offerings.”

RSLE, a joint venture between RoseStreet Labs, LLC and Sumitomo Chemical Corporation of Tokyo, announced in July the successful implementation of a Cooperative Research and Development Agreement (CRADA) with LANL to produce the full-spectrum photovoltaic technology.

“The CRADA is a Department of Energy-generated contract that makes collaborative R&D activities at the lab possible,” said Erickson. “It stipulates work to be conducted, deliverables expected and parties responsible under a specific timeline. It also speaks to how intellectual property is treated during the work period. The initial CRADA effort is scheduled to last 14 months.”

Work has begun and will be conducted primarily at LANL for initial prototype photovoltaic device development in cooperation with the RSLE technical staff. Together, they hope to create a more efficient solar cell using a scalable manufacturing process amenable to low-cost manufacturing.

ENABLE technology was developed at LANL and earned an R&D 100 Award in 2006. According to Mark Hoffbauer, lead inventor and principal investigator, the technology has been under development at LANL since about 1998. When RSLE became aware of Hoffbauer and his team’s work, it approached LANL to discuss the potential for collaboration.

“RoseStreet was watching various universities and research institutes for potential science and technology to accelerate its commercialization of full-spectrum photovoltaics,” said Forcier. ENABLE was a winner of the R&D 100 award as was RoseStreet’s multiband technology. Both principal investigators, Wladek Walukiewicz and Mark Hoffbauer, met at the awards ceremony and started discussions on exploring ENABLE as a potential method to enhance RoseStreet’s planned products.

Hoffbauer explained that growing thin films and etching minute features are fundamental to the fabrication of modern semiconductors, photovoltaic devices, light-emitting diodes, solid-state lasers, high-capacity microbatteries and other technologies important to our nation’s energy security.

“Most fabrication processes involve overcoming some kind of energy-activation barrier to achieve desired materials properties,” he said. “These barriers usually require energy in the form of heat to initiate the requisite physical or chemical processes. Such barriers require that energy—usually in the form of heat—be input into the system to initiate the requisite physical or chemical processes.”

These barriers can be overcome with the ENABLE process, he said, by using a powerful laser-sustained plasma that creates high kinetic-energy neutral atoms that are extracted and collimated, or aligned, to form a beam. This energetic neutral atom beam is then used to directly activate surface chemical reactions, forming the basis of a specialized tool for both growing and etching thin film materials at the nanoscale called ENABLE, which stands for Energetic Neutral Atom Beam Lithography and Epitaxy.

Hoffbauer believes ENABLE’s uniqueness comes from its ability to produce either neutral nitrogen or oxygen atoms with kinetic energies of a few electron volts and simultaneously deliver to a substrate an enormous flux of energetic atoms, easily four orders of magnitude larger than any other available neutral atom source. This combination of energy and flux distinguishes ENABLE from competing technologies, allowing numerous thin-film-growth and nanofabrication applications to be explored at commercially feasible processing rates.

“ENABLE comprises a single materials synthesis and modification technique for producing and integrating advanced thin film materials and nanoscale structures,” said Hoffbauer. “By removing the constraints inherent to thermal activation, ENABLE fundamentally alters the thinking behind creating, transforming and integrating nanoscale materials into useful devices.”

Beyond producing more efficient solar energy generation, other possible uses of the ENABLE technology include high-efficiency solid-state lighting (true white light), high-power and high-frequency electronics modules for communications, and photoelectrochemical water splitting to produce hydrogen.

“Additional applications will include solid-state laser diodes of any color, better photodetectors, and water purification,” said Hoffbauer. “I expect the average person will benefit by way of both energy production and use. My estimate is that we’re three to five years from commercially available products.”

According to Laura Barber, technology management team leader for LANL’s technology transfer division, the goal of the LANL-RSLE partnership is to incorporate the ENABLE technology into practical devices that ultimately will benefit the nation’s energy security.

“Our nation’s energy security is intimately tied to our national security and consequently is an important mission of the DOE Laboratories,” she said. “U.S. taxpayers will benefit from this technology when it has been incorporated into practical devices with greater energy efficiencies.”

Seeing the ENABLE technology commercialized and making materials to benefit the nation and energy security is what Hoffbauer and his colleagues hope to accomplish through their work. For Erickson, success equals a collaboration that leads to important technology breakthroughs for the development of commercially available, highly efficient solar panels for the benefit of the world community.

According to Forcier, RSLE’s goal is to evaluate ENABLE as a better way of manufacturing its product technology. They are hopeful that ENABLE will play a key role in the roll out of high-volume manufacturing of its photovoltaic products and also provide unique material properties that support RSLE’s quest for higher conversion efficiencies of the sun’s energy into electrical power.

“This is going to be a huge undertaking,” said Erickson, “but the science is very sound and everyone involved has a healthy sense of urgency to put together the necessary resources to commercialize ENABLE successfully.”

Mig Owens is a communications specialist at Los Alamos National Laboratory.

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