Trapping light with an optical version of a whispering gallery, researchers at the National Institute of Standards and Technology (NIST) have developed a nanoscale coating for solar cells that enables them to absorb about 20 percent more sunlight than uncoated devices. The coating, applied with a technique that could be incorporated into manufacturing, opens a new path for developing low-cost, high-efficiency solar cells with abundant, renewable and environmentally friendly materials.
The coating consists of thousands of tiny glass beads, only about one-hundredth the width of a human hair. When sunlight hits the coating, the light waves are steered around the nanoscale bead, similar to the way sound waves travel around a curved wall such as the dome in St. Paul’s Cathedral in London. At such curved structures, known as acoustic whispering galleries, a person standing near one part of the wall easily hears a faint sound originating at any other part of the wall.
Whispering galleries for light were developed about a decade ago, but researchers have only recently explored their use in solar-cell coatings. In the experimental set up devised by a team including Dongheon Ha of NIST and the University of Maryland’s NanoCenter, the light captured by the nanoresonator coating eventually leaks out and is absorbed by an underlying solar cell made of gallium arsenide.
Using a laser as a light source to excite individual nanoresonators in the coating, the team found that the coated solar cells absorbed, on average, 20 percent more visible light than bare cells. The measurements also revealed that the coated cells produced about 20 percent more current.
The study is the first to demonstrate the efficiency of the coatings using precision nanoscale measurements, said Ha. “Although calculations had suggested the coatings would enhance the solar cells, we could not prove this was the case until we had developed the nanoscale measurement technologies that were needed,” he noted.
This work was described (link is external) in a recent issue of Nanotechnology by Ha, collaborator Yohan Yoon of NIST and Maryland’s NanoCenter, and NIST physicist Nikolai Zhitenev.
The team also devised a rapid, less-costly method of applying the nanoresonator coating. Researchers had previously coated semiconductor material by dipping it in a tub of the nanoresonator solution. The dipping method takes time and coats both sides of the semiconductor even though only one side requires the treatment.
In the team’s method, droplets of the nanoresonator solution are placed on just one side of the solar cell. A wire-wound metal rod is then pulled across the cell, spreading out the solution and forming a coating made of closely packed nanoresonators. This is the first time that researchers have applied the rod method, used for more than a century to coat material in a factory setting, to a gallium arsenide solar cell.
“This is an inexpensive process and is compatible with mass production,” said Ha.
The Latest on: Solar cell efficiency
via Google News
The Latest on: Solar cell efficiency
- New Breakthrough Could Slash Solar Prices To New Lows on October 6, 2018 at 12:00 pm
Today, most commercial solar cells are made from crystalline silicon, which has a relatively high efficiency of around 22%. Though silicon, the raw material for these solar cells, is abundant ... […]
- Bottling the sun: UW researchers combine solar cell, battery to store energy in liquid on October 5, 2018 at 12:41 pm
... in Jin’s lab on the UW campus is eight times better than the team’s previous efforts and on par with the efficiency of solar cells on the market now, with the benefit of being able to use the elec... […]
- German scientists work on efficiency boosting cell concept on October 5, 2018 at 7:28 am
The SF effect has been observed in certain materials, and essentially allows one light particle (photon) to generate two electron hole pairs as it is absorbed, instead of just one, potentially doublin... […]
- Fuel cells combined with wind, solar are the next clean energy tech on October 4, 2018 at 6:14 pm
NORTH CANTON, Ohio -- Wind and solar farms are generating clean power at lower ... either underground or in tanks for use by gas turbines or even more efficient fuel cells, he said. The hydrogen, in e... […]
- Boosting the efficiency of silicon solar cells on October 4, 2018 at 11:42 am
A solar cell's efficiency indicates what percentage of the solar energy radiated into the cell is converted into electrical energy. The theoretical limit for silicon solar cells is 29.3 percent due to ... […]
- SunPower’s US-Based Future Gets Underway With Acquisition Of SolarWorld Assets & Solar Tariff Exclusion on October 4, 2018 at 8:20 am
According to SunPower, the company has also already injected fresh capital into the factory as it plans to begin manufacturing its high-efficiency ... contact (IBC) solar cells and modules would ... […]
- HZB researchers are used to boost the efficiency of silicon solar cells on October 4, 2018 at 8:06 am
The trick: they incorporate layers of organic molecules into the solar cell. These layers utilise a quantum mechanical process known as singlet exciton fission to split certain energetic light (green ... […]
- New solar hybrid combines energy storage with record system efficiency on October 4, 2018 at 2:14 am
"At this efficiency range, without using the expensive solar cells, it should be quite competitive with other renewable energy technologies. Then I think commercialization could be possible." The sola... […]
- ASU researcher innovates solar energy technology in space on October 3, 2018 at 12:49 pm
This method creates a solar cell that’s more efficient at converting sunlight into electricity than conventional solar cells, which are manufactured using standard high-temperature methods. Pioneered ... […]
via Bing News