New Dye Will Lead To More Efficient Solar Energy Technology

RALEIGH, N.C. — December 12, 2011 — A North Carolina State University invention has significant
potential to improve the efficiency of solar cells and other technologies that derive energy from

Dr. Ahmed El-Shafei’s research group invented a new “sensitizer,” or dye, that harvests more
ambient and solar light than any dyes currently on the market for use in dye-sensitized solar cells

NCSU-10 can be used to create more effective solar cells.

“A third-party solar energy company compared our new dye, NCSU-10, against the
state-of-the-art dye on the market. Our dye had 14 percent more power density,” says El-Shafei, an
assistant professor in the Textile Engineering, Chemistry and Science department. “In other words,
NCSU-10 allows us to harvest more energy from the same amount of light.”

The new dye should significantly boost the efficiency of DSSCs, which have a host of
applications. Indoors, these DSSCs can be used in technology to power cellular phones, laptop
computers and MP3 players using ambient light. Outdoors, they could be used in conventional solar
arrays or in improved energy-driven applications for building-integrated photovoltaic products
including, but not limited to, windows, facades and skylights.

Compared to the state-of-the-art dye on the market, NCSU-10 can absorb more photons at lower
dye concentrations, and can therefore be used to create more effective solar cells on windows and
facades while still allowing the windows to be highly transparent.

DSSCs are made of inexpensive and environmentally benign materials including a dye, an
electrolyte and titanium dioxide (TiO2) — the white component used in toothpaste. DSSCs work by
absorbing photons, or discrete packets of light energy, from incident light (or direct light that
falls on a surface) to create free electrons in nanoporous semiconductors such as TiO2, in the
cell. These electrons travel to the outside circuit to generate an electric current. Owing to their
independence on the angle of incident light and high response to low level of lighting conditions,
DSSCs outperform conventional silicon photovoltaic by 20 to 40 percent under diffuse light, on
cloudy and/or rainy days, and in indoor ambient light, which make DSSCs a unique class of

A patent is pending on the new dye, and the university is in communication with potential
industry partners about licensing use of NCSU-10, as well as funding additional research in this

Posted on December 13, 2011

Source: North Carolina State University