Photovoltaic Paint
Heats Up
Charles W. Thurston, Contributing Writer
Avariety of research companies and universities are work- ing to advance spray-on organic photovoltaics (OPV) with the aim of coating glass, curved plastics and other
materials at commercial volume in the near future. A key to
several of these developments is that a manufacturing process
likely will evolve using roll-to-roll or sheet-to-sheet technology
in conjunction with jet spray.
Part of the funding for these advances is coming from the
U.S. Department of Energy’s (DOE) SunShot program, aimed at
improving solar and driving down the cost. The federal government estimates the United States can save $40 billion per year
by reducing energy use in commercial buildings by 20 percent
by 2020.
In early November, Scottsdale, AZ-based NanoFlex Power
Corp. won a $1.35 million cooperative award from SunShot,
under the “Next Generation Photovoltaics 3” program; it was
the only project awarded for OPV research and development
in this round of financing, NanoFlex announced. The company is conducting Gallium Arsenide (GaAs) solar cells research
with the University of Southern California and the University of
Michigan, which are leaders in the field of organic electronics,
including organic light emitting diodes, or OLEDs, and OPV.
Under the award, the University of Michigan “will advance
the practical viability of OPV by demonstrating reliable, large
area and high-efficiency organic multi-junction cells based on
small molecule materials systems.” The project’s goals focus on
“improving the conversion efficiency of OPV cells to more than
18 percent, increasing cell lifetimes to over 20 years, and dem-
onstrating ultra-rapid fabrication processes through proprietary
vapor phase deposition and roll-to-roll application of package
encapsulation.”
Early OPV research yielded light converting efficiency of only
six or seven percent, but those levels have been nearly doubled,
according to several different project announcements this year.
Typically, solar glass coatings trap both external solar light and
internally-generated light.
And last year, New Energy Technologies, based in
Columbia, MD, moved into Phase 2 of its Cooperative
Research and Development Agreement (CRADA) with DOE’s
National Renewable Energy Laboratory (NREL) to advance
the development of its Solar Window technology, capable of
generating electricity on glass. Included in this stage of work
is the commercialization of roll-to-roll or sheet-to-sheet manufacturing techniques.
In March, NREL tested a SolarWindow version that was
about three square feet and was transparent. “The window per-
formed 50 times better than previous versions and set the re-
cord as the most efficient organic photovoltaic cell (OPV) ever
tested by the NREL,” Solar Technologies indicated. NREL oper-
ates the Device Performance Measurement Laboratory for such
materials testing. New Energy Technologies points out that its
process“ does not require expensive high-temperature or high-
vacuum production methods, but rather, can be sprayed on to
glass at room temperature.”
“Accomplishing these goals allows us to now advance to-
wards larger area, commercial scale windows while maintaining
uniform, neutral colors and scalable power,” said John Conklin,
the president and CEO of New Energy Technologies.
Another team at work on PV paint is at the University of
Sheffield, involving sprayed perovskite, a calcium titanium oxide mineral that absorbs light nearly as well as silicon. This project has achieved a reported 11 percent efficiency thus far. CW
