By putting together the formation technology for high quality light
absorption layers and the advanced integration technology that had been
developed at an earlier stage, the researchers achieved for the first
time a high conversion efficiency, over 18 percent, of a CIGS
photovoltaic sub-module. The developed technology is a core elemental
technology for the improvement of the conversion efficiency of
photovoltaic modules and is applicable to a wide variety of photovoltaic
modules including large-area modules and flexible modules. This
technology is expected to contribute to the improvement of the
conversion efficiency of mass-produced photovoltaic modules, a reduction
in power generation costs, and improvements in the functionality of
photovoltaic modules.
http://www.photonicsonline.com/doc/a-cigs-photovoltaic-sub-module-with-conversion-efficiency-of-percent-0001
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Thursday, January 30, 2014
New Study Could Lead To Paradigm Shift In Organic Solar Cell Research
News | November 19, 2013
New Study Could Lead To Paradigm Shift In Organic Solar Cell Research
Now a Stanford University research team is weighing in on the controversy. Their findings, published in the Nov. 17 issue of the journal Nature Materials, indicate that the predominant working theory is incorrect, and could steer future efforts to design materials that boost the performance of organic cells.
"We know that organic photovoltaics are very good," said study coauthor Michael McGehee, a professor of materials science and engineering at Stanford. "The question is, why are they so good? The answer is controversial."
A typical organic solar cell consists of two semiconducting layers made of plastic polymers and other flexible materials. The cell generates electricity by absorbing particles of light, or photons.
When the cell absorbs light, a photon knocks out an electron in a polymer atom, leaving behind an empty space, which scientists refer to as a hole. The electron and the hole immediately form a bonded pair called an exciton. The exciton splits, allowing the electron to move independently to a hole created by another absorbed photon. This continuous movement of electrons from hole to hole produces an electric current.
In the study, the Stanford team addressed a long-standing debate over what causes the exciton to split.
"To generate a current, you have to separate the electron and the hole," said senior author Alberto Salleo, an associate professor of materials science and engineering at Stanford. "That requires two different semiconducting materials. If the electron is attracted to material B more than material A, it drops into material B. In theory, the electron should remain bound to the hole even after it drops.
"The fundamental question that's been around a long time is, how does this bound state split?"
Some like it hot
One explanation widely accepted by scientists is known as the "hot exciton effect." The idea is that the electron carries extra energy when it drops from material A to material B. That added energy gives the excited ("hot") electron enough velocity to escape from the hole.
But that hypothesis did not stand up to experimental tests, according to the Stanford team.
"In our study, we found that the hot exciton effect does not exist," Salleo said. "We measured optical emissions from the semiconducting materials and found that extra energy is not required to split an exciton."
So what actually causes electron-hole pairs to separate?
"We haven't really answered that question yet," Salleo said. "We have a few hints. We think that the disordered arrangement of the plastic polymers in the semiconductor might help the electron get away."
In a recent study, Salleo discovered that disorder at the molecular level actually improves the performance of semiconducting polymers in solar cells. By focusing on the inherent disorder of plastic polymers, researchers could design new materials that draw electrons away from the solar cell interface where the two semiconducting layers meet, he said.
"In organic solar cells, the interface is always more disordered than the area further away," Salleo explained. "That creates a natural gradient that sucks the electron from the disordered regions into the ordered regions. "
Improving energy efficiency
The solar cells used in the experiment have an energy-conversion efficiency of about 9 percent. The Stanford team hopes to improve that performance by designing semiconductors that take advantage of the interplay between order and disorder.
"To make a better organic solar cell, people have been looking for materials that would give you a stronger hot exciton effect," Salleo said. "They should instead try to figure out how the electron gets away without it being hot. This idea is pretty controversial. It's a fundamental shift in the way people think about photocurrent generation."
http://www.photonicsonline.com/doc/new-study-could-lead-to-paradigm-shift-in-organic-solar-cell-research-0001
Saturday, January 25, 2014
Color This New Solar Cell Efficiency Breakthrough Blue
The
holy grail of our research is not necessarily to boost efficiencies as
high as they can theoretically go, but rather to combine increases in
efficiency to the kind of large-scale roll-to-roll printing or
processing technologies that will help us drive down costs.
Read more at http://cleantechnica.com/2014/01/25/new-solar-cell-efficiency-breakthrough-harvests-blue-light/#jfhq1j5Du6HoudUH.99
http://cleantechnica.com/2014/01/25/new-solar-cell-efficiency-breakthrough-harvests-blue-light/Read more at http://cleantechnica.com/2014/01/25/new-solar-cell-efficiency-breakthrough-harvests-blue-light/#jfhq1j5Du6HoudUH.99
The
thin film angle is important to solar cell affordability because,
although thin film is not as efficient as the gold standard (that would
be silicon), it is far more inexpensive to manufacture and it has a greater range of applications.
Read more at http://cleantechnica.com/2014/01/25/new-solar-cell-efficiency-breakthrough-harvests-blue-light/#jfhq1j5Du6HoudUH.99
Read more at http://cleantechnica.com/2014/01/25/new-solar-cell-efficiency-breakthrough-harvests-blue-light/#jfhq1j5Du6HoudUH.99
The
thin film angle is important to solar cell affordability because,
although thin film is not as efficient as the gold standard (that would
be silicon), it is far more inexpensive to manufacture and it has a greater range of applications.
The new Argonne solar cell research pivots on the manufacturing process to harvest more light from the blue end of the spectrum.
Read more at http://cleantechnica.com/2014/01/25/new-solar-cell-efficiency-breakthrough-harvests-blue-light/#jfhq1j5Du6HoudUH.99
The new Argonne solar cell research pivots on the manufacturing process to harvest more light from the blue end of the spectrum.
Read more at http://cleantechnica.com/2014/01/25/new-solar-cell-efficiency-breakthrough-harvests-blue-light/#jfhq1j5Du6HoudUH.99
The
thin film angle is important to solar cell affordability because,
although thin film is not as efficient as the gold standard (that would
be silicon), it is far more inexpensive to manufacture and it has a greater range of applications.
The new Argonne solar cell research pivots on the manufacturing process to harvest more light from the blue end of the spectrum.
Read more at http://cleantechnica.com/2014/01/25/new-solar-cell-efficiency-breakthrough-harvests-blue-light/#jfhq1j5Du6HoudUH.99
The new Argonne solar cell research pivots on the manufacturing process to harvest more light from the blue end of the spectrum.
Read more at http://cleantechnica.com/2014/01/25/new-solar-cell-efficiency-breakthrough-harvests-blue-light/#jfhq1j5Du6HoudUH.99
Tuesday, January 14, 2014
Triangle researchers find possible solution to solar energy problem
Triangle researchers find possible solution to solar energy problem
CHAPEL HILL — A team of
researchers led by a UNC-Chapel Hill chemistry professor has discovered a
potential solution to one of the fundamental problems of generating
large amounts of energy from the sun’s rays: how to store some of the
power so it’s available at night.
The scientists, who also include researchers from N.C. State University, found a new way to use solar energy to split molecules of water into its atomic-level components: oxygen and hydrogen. The hydrogen can then be burned for fuel, generating only water as waste, which can then be recycled to be split again.
The hydrogen could be created and used by infrastructure similar to generators and solar arrays that are already familiar, said Tom Meyer, director of the federally funded Energy Frontier Research Center at UNC-CH, who led the research.
“Part of a solar array, instead of just making electricity during the day, could in fact be making chemicals,” he said. “So when the sun goes down, you just run the chemicals through your power plant, and you extract the energy back out as you need it.”
Only a fraction of the energy being generated in the U.S. now comes from solar or from wind, which also is intermittent. But it’s enough to already create some distribution problems, and the issue is expected to increase as more renewable energy sources are added to the national grid.
Meyer had been researching how to turn solar energy into fuels for several decades while also working on other projects, he said. Parts of the process had long been apparent, but it took the addition of nanoparticle engineering to capitalize on the potential.
That’s where Gregory Parsons’ group at N.C. State University came in, said Meyer. Parsons is director of NCSU’s Nanotechnology Initiative.
The process uses two basic components. One, a molecule called a chromophore-catalyst assembly, absorbs sunlight and then begins breaking down the water molecules. The other, a nanoparticle to which thousands of chromophore-catalyst assemblies are attached, is part of a film that shuttles away electrons, a vital part of deconstructing the water molecules.
It didn’t work smoothly, though, until Meyer turned to Parsons’ team, which found a method for coating the nanoparticles with extremely thin layers of titanium dioxide. The scientists found that the nanoparticles could then carry away electrons quickly enough to make the process work well. They also figured out how to build a protective coating that keeps the chromophore-catalyst assembly tethered firmly to the nanoparticle, as the two pieces had tended to break apart.
More efficiency expected
The process currently generates hydrogen equal to about 1 percent of the energy in the sunlight received. But now that it’s clear the concept works, the researchers think there’s little doubt that they can improve the efficiency, Meyer said. They hope to reach their goal of at least 15 percent, which is similar to the efficiency of current commercial solar cells.
Also, they plan to explore the potential for using the same process to turn the greenhouse gas carbon dioxide into a carbon-based fuel such as methanol that could be burned in a closed loop, generating carbon dioxide to be used again.
The scientists, who also include researchers from N.C. State University, found a new way to use solar energy to split molecules of water into its atomic-level components: oxygen and hydrogen. The hydrogen can then be burned for fuel, generating only water as waste, which can then be recycled to be split again.
The hydrogen could be created and used by infrastructure similar to generators and solar arrays that are already familiar, said Tom Meyer, director of the federally funded Energy Frontier Research Center at UNC-CH, who led the research.
“Part of a solar array, instead of just making electricity during the day, could in fact be making chemicals,” he said. “So when the sun goes down, you just run the chemicals through your power plant, and you extract the energy back out as you need it.”
Only a fraction of the energy being generated in the U.S. now comes from solar or from wind, which also is intermittent. But it’s enough to already create some distribution problems, and the issue is expected to increase as more renewable energy sources are added to the national grid.
Meyer had been researching how to turn solar energy into fuels for several decades while also working on other projects, he said. Parts of the process had long been apparent, but it took the addition of nanoparticle engineering to capitalize on the potential.
That’s where Gregory Parsons’ group at N.C. State University came in, said Meyer. Parsons is director of NCSU’s Nanotechnology Initiative.
The process uses two basic components. One, a molecule called a chromophore-catalyst assembly, absorbs sunlight and then begins breaking down the water molecules. The other, a nanoparticle to which thousands of chromophore-catalyst assemblies are attached, is part of a film that shuttles away electrons, a vital part of deconstructing the water molecules.
It didn’t work smoothly, though, until Meyer turned to Parsons’ team, which found a method for coating the nanoparticles with extremely thin layers of titanium dioxide. The scientists found that the nanoparticles could then carry away electrons quickly enough to make the process work well. They also figured out how to build a protective coating that keeps the chromophore-catalyst assembly tethered firmly to the nanoparticle, as the two pieces had tended to break apart.
More efficiency expected
The process currently generates hydrogen equal to about 1 percent of the energy in the sunlight received. But now that it’s clear the concept works, the researchers think there’s little doubt that they can improve the efficiency, Meyer said. They hope to reach their goal of at least 15 percent, which is similar to the efficiency of current commercial solar cells.
Also, they plan to explore the potential for using the same process to turn the greenhouse gas carbon dioxide into a carbon-based fuel such as methanol that could be burned in a closed loop, generating carbon dioxide to be used again.
Price: 919-829-4526
Read more here: http://www.newsobserver.com/2014/01/14/3532549/triangle-researchers-find-possible.html#storylink=cpy
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