By tweaking the smallest of parts, a trio of University at
Buffalo (UB) engineers is hoping to dramatically increase the amount of
sunlight that solar cells convert into electricity.
With military colleagues, the UB researchers have shown that
embedding charged quantum dots into photovoltaic cells can improve electrical
output by enabling the cells to harvest infrared light, and by increasing the
lifetime of photoelectrons.
The research appeared online in Nano Letters. The research team included Vladimir Mitin, Andrei
Sergeev, and Nizami Vagidov, faculty members in UB's Electrical Engineering Department;
Kitt Reinhardt of the Air Force Office of Scientific Research; and John Little
and advanced nanofabrication expert Kimberly Sablon of the U.S. Army Research
Laboratory.
Mitin, Sergeev, and Vagidov have founded a company,
OPtoElectronic Nanodevices LLC. (OPEN LLC.), to bring the innovation to the
market.
The idea of embedding quantum dots into solar panels is not new:
According to Mitin, scientists had proposed about a decade ago that this
technique could improve efficiency by allowing panels to harvest invisible,
infrared light in addition to visible light. However, intensive efforts in this
direction have previously met with limited success.
The UB researchers and their colleagues have not only
successfully used embedded quantum dots to harvest infrared light; they have
taken the technology a step further, employing selective doping so that quantum
dots within the solar cell have a significant built-in charge.
This built-in charge is beneficial because it repels electrons,
forcing them to travel around the quantum dots. Otherwise, the quantum dots
create a channel of recombination for electrons, in essence
"capturing" moving electrons and preventing them from contributing to
electric current.
The technology has the potential to increase the efficiency of
solar cells up to 45%, said Mitin, a SUNY Distinguished Professor. Through UB's
Office of Science, Technology Transfer, and Economic Outreach (STOR), he and
his colleagues have filed provisional patent applications to protect their
technology.
"Clean technology will really benefit the region, the state, the
country," Mitin said. "With high-efficiency solar cells, consumers
can save money and providers can have a smaller solar field that produces more
energy."
Mitin and his colleagues have already invested significant
amounts of time in developing the quantum dots with a built-in-charge, dubbed
"Q-BICs." To further enhance the technology and bring it to the
market, OPEN LLC is now seeking funding from private investors and federal
programs.
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