“To get maximum efficiency when converting solar power into
electricity, you want a solar panel that can absorb nearly every single
photon of light, regardless of the sun’s position in the sky,"
said Shawn-Yu Lin, professor of physics at Rensselaer and a member of
the university’s Future Chips Constellation, who led the research
project. "Our new antireflective coating makes this possible.”
—
“After a silicon surface was treated with Lin’s new nanoengineered
reflective coating, however, the material absorbed 96.21 percent of
sunlight shone upon it - meaning that only 3.79 percent of the sunlight
was reflected and unharvested. This huge gain in absorption was consistent
across the entire spectrum of sunlight, from UV to visible light and
infrared, and moves solar power a significant step forward toward economic
viability.
“Lin’s new coating also successfully tackles the tricky
challenge of angles.
“Most surfaces and coatings are designed to absorb light - i.e.,
be antireflective - and transmit light - i.e., allow the light to pass
through it - from a specific range of angles. Eyeglass lenses, for example,
will absorb and transmit quite a bit of light from a light source directly
in front of them, but those same lenses would absorb and transmit considerably
less light if the light source were off to the side or on the wearer’s
periphery.”
—
“Typical antireflective coatings are engineered to transmit light
of one particular wavelength. Lin’s new coating stacks seven of
these layers, one on top of the other, in such a way that each layer
enhances the antireflective properties of the layer below it. These
additional layers also help to "bend" the flow of sunlight
to an angle that augments the coating’s antireflective properties.
This means that each layer not only transmits sunlight, it also helps
to capture any light that may have otherwise been reflected off of the
layers below it.
“The seven layers, each with a height of 50 nanometers to 100
nanometers, are made up of silicon dioxide and titanium dioxide nanorods
positioned at an oblique angle - each layer looks and functions similar
to a dense forest where sunlight is "captured" between the
trees. The nanorods were attached to a silicon substrate via chemical
vapor disposition, and Lin said the new coating can be affixed to nearly
any photovoltaic materials for use in solar cells, including III-V multi-junction
and cadmium telluride.”
