Momentum - The Magazine for Virginia Tech Mechanical Engineering Vol. 1 No. 4 | Page 15

Using screen printing technology, low temperature titanium
oxide paste is applied to the
plastic in a process that takes
mere seconds. These panels
make up multiple layers of the
five layer finished product.

your devices, to powering your LED lights.”
The panels, Priya said, can also be made to any
design, so they could become window shades and
curtains as well, absorbing sunlight through windows.
“The properties of the panels are such that there
are really few limitations in terms of light source,”
Priya said. “And the fact that we are dealing with an
emerging technology, means we will be able to expand the utility of the panels as we go forward.”
Currently, the efficiency of the cells is nearly on par
with the heavier, rigid silicon structures, but, Priya
said, at panel-level there is some research required.
Still, it is likely the new flexible panels will overtake
their rigid cousins soon.
“Amorphous silicon is a fairly mature technology
running at about 13-15 percent efficiency,” he said.
“Our panels right now operate around 10 percent
at the panel size. At smaller, less-useful sizes, the
efficiency increases, and so we can see a potential for
much greater energy collection efficiencies.”
The flexible panels, as they approach the conversion efficiency of rigid silicon and glass, can also be
incorporated into products that the older technology
cannot compete with – such as military uniforms
and backpacks, items Priya’s lab is working on now
with the U.S. Army’s Communications-Electronics
Research, Development, and Engineering Center. By
adding flexible panels to these items, soldiers will

become their own recharging stations, resulting in reduction of the logistical footprint of a fighting force in
the field, as well as the weight each individual soldier
must carry on his or her back.
“Right now we are on the cutting edge of this
technology,” Priya said. “Our edge is in the ability to
fabricate large-area modules with high efficiency. We
are actively working to integrate the product with the
market and we see a wide variety of uses for the technology, from clothing to windows, to smart buildings
to UAVs to mobile charging stations.”
The work of Priya and his team is detailed in the
papers, The Controlling Mechanism for Potential Loss
in CH3NH3PbBr3 Hybrid Solar Cells, published in the
July issue of ACS Energy Letters, and Scaling of the
Flexible Dye Sensitized Solar Cell Module, available
online now in the journal Solar Energy Materials and
Solar Cells. The article was published in the journal’s
December edition.
By creating panels that capture a wide variety of
light wavelengths, Virginia Tech engineers are opening
a door to an entirely new area of light and energy
recycling that could make saving energy as easy as
hanging a curtain. Another paper demonstrating the
stability of the cells was published by ACS Energy
Letters in October under the title, Improved Phase
Stability of Formamidinium Lead Triiodide Perovskite
by Strain Relaxation.