Team extracts more energy from sunlight with advanced solar panels


Date:
October 6, 2020
Source:
University of Illinois at Urbana-Champaign, News Bureau
Summary:
Researchers working to maximize solar panel efficiency said layering
advanced materials atop traditional silicon is a promising path to
eke more energy out of sunlight. A new study shows that by using a
precisely controlled fabrication process, researchers can produce
multilayered solar panels with the potential to be 1.5 times more
efficient than traditional silicon panels.



FULL STORY ========================================================================== Researchers working to maximize solar panel efficiency said layering
advanced materials atop traditional silicon is a promising path to eke
more energy out of sunlight. A new study shows that by using a precisely controlled fabrication process, researchers can produce multilayered
solar panels with the potential to be 1.5 times more efficient than
traditional silicon panels.


==========================================================================
The results of the study led by University of Illinois Urbana-Champaign engineer Minjoo Larry Lee are published in the journal Cell Reports
Physical Sciences.

"Silicon solar panels are prevalent because they are affordable and can
convert a little over 20% of the sun's light into usable electricity,"
said Lee, a professor of electrical and computer engineering and
Holonyak Micro and Nanotechnology Lab affiliate. "However, just like
silicon computer chips, silicon solar cells are reaching the limit of
their abilities, so finding a way to increase efficiency is attractive to energy providers and consumers." Lee's team has been working to layer the semiconductor material gallium arsenide phosphide onto silicon because
the two materials complement each other. Both materials absorb visible
light strongly, but gallium arsenide phosphide does so while generating
less waste heat. In contrast, silicon excels at converting energy from
the infrared part of the solar spectrum just beyond what our eyes can see,
Lee said.

"It is like a sports team. You are going to have some fast people,
some who are strong and some with great defensive skills," he said. "In
a similar way, tandem solar cells work as a team and take advantage of
the best properties of both materials to make a single, more efficient
device." While gallium arsenide phosphide and other semiconductor
materials like it are efficient and stable, they are expensive, so
making panels composed entirely from them is not reasonable for mass
production at this time. Hence, Lee's team uses low-cost silicon as a
starting point for its research.

During fabrication, material defects find their way into the layers, particularly at interfaces between the silicon and gallium arsenide
phosphide, Lee said. Tiny imperfections form whenever materials with
different atomic structure are layered onto silicon, compromising both performance and reliability.

"Anytime you switch from one material to another, there is always a risk
of creating some disorder in the transition," Lee said. "Shizhao Fan,
the lead author of the study, developed a process for forming pristine interfaces in the gallium arsenide phosphide cell, which led to a vast improvement over our earlier work in this area." "Eventually, a utility company could use this technology to get 1.5 times more energy out of
the same amount of land on its solar farms, or a consumer could use 1.5
times less space for rooftop panels," he said.

Lee said obstacles remain on the path to commercialization, but he is
hopeful that energy providers and consumers will see the value in using
stable materials to achieve a performance boost.


========================================================================== Story Source: Materials provided by University_of_Illinois_at_Urbana-Champaign,_News_Bureau.

Original written by Lois Yoksoulian. Note: Content may be edited for
style and length.


========================================================================== Journal Reference:
1. Shizhao Fan, Zhengshan J. Yu, Ryan D. Hool, Pankul Dhingra, William
Weigand, Mijung Kim, Erik D. Ratta, Brian D. Li, Yukun Sun,
Zachary C.

Holman, Minjoo L. Lee. Current-Matched III-V/Si Epitaxial Tandem
Solar Cells with 25.0% Efficiency. Cell Reports Physical Science,
2020; 1 (9): 100208 DOI: 10.1016/j.xcrp.2020.100208 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/10/201006114200.htm

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