Solar machine: The CEO of Natcore Technology demonstrates a prototype AR-Box, which uses a new liquid-based deposition technology to apply antireflective coatings.
Energy
New Manufacturing Tech Could Mean Cheaper Solar Cells
Startup Natcore says its process could reduce costs and enable new nanostructured designs.
- Tuesday, January 3, 2012
- By Kevin Bullis
A novel way to make thin, uniform coatings developed at Rice University could reduce the cost of making conventional silicon solar cells, and could open the way for new kinds of solar cells that are far more efficient or cheaper than conventional ones.
The technology, which deposits coatings in a low-temperature, liquid-based process rather than the high-temperature gas-based process used now, is being commercialized by Natcore Technology, a startup in Red Bank, New Jersey. The company plans to use the technology to replace a standard step in conventional solar cell manufacturing—adding an antireflective coating to silicon wafers to help them to absorb more light. It will also offer a more advanced antireflection technology, called black silicon.
At the same time, Natcore is developing more advanced applications of the process, including fabricating solar cells made of carbon nanotubes or nanoscale crystals called quantum dots. Such solar cells will probably take years to commercialize, but could far outperform conventional solar cells. Nano solar cells have been attempted before, but the company thinks its new manufacturing technology could make them affordable.
As a replacement for high-temperature processes on a conventional manufacturing line, the liquid-based process can lower manufacturing costs. Natcore's CEO, Charles Provini, estimates that replacing a conventional coating machine with one of his company's could save a solar manufacturer about $1 million in electricity costs per year.
Manufacturers don't currently use liquid-based processes for antireflection coatings in part because it's been difficult to make the coating uniform enough for solar cells. The problem arises from the way a liquid process typically works. The coating forms as reactants in the liquid interact with a surface. As the reactants are used up, the rates of deposition change, resulting in variations in the thickness of the coating. Researchers at Rice addressed this problem by developing a system for continuously replenishing the reactants while also closely monitoring the thickness of the films.
One of Natcore's advanced nano solar cell designs involves depositing layers of quantum dots on a silicon solar cell. The quantum dots are designed to absorb colors that silicon doesn't, potentially doubling the efficiency of solar cells. This has been tried before, but forming a layer of quantum dots has required expensive processing technology, and it has proven difficult to space the quantum dots to avoid unwanted electrical discharges between them. The Natcore process is inexpensive, and it provides a means for controlling the arrangement of the quantum dots by coating them with a layer of silicon dioxide that acts as a spacer. The company has decided to start by coating conventional silicon solar cells to make it easier for the industry to adopt the technology, but could eventually do away with silicon wafers for an entirely quantum-dot-based solar cell that uses more than one type of quantum dot to efficiently absorb the entire range of wavelengths in sunlight.
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tarwin
4 Comments
- 505 Days Ago
- 01/03/2012
If you have problems with liquids changing as they move over the surface wouldn't inkjet deposition make sense?
Sagentialtd
3 Comments
- 502 Days Ago
- 01/06/2012
Continuing improvements in solar cell technology
Solar cell improvements tend to come in two flavours: lower costs, and higher efficiency. Natcore Technology, a startup company in New Jersey, is hoping to achieve both, using work by researchers at Rice University who have developed a novel liquid based thin film coating process to replace the gas based deposition processes used in manufacturing solar cells. In one solar cell design, thinner, cheaper silicon wafers can be used since the low temperatures used in the coating process do not require the thick wafers resistant to the thermal stresses of high temperature manufacturing processes. In another, “tandem”, solar cell design, the liquid coating process allows absorbers of different light wavelengths to be laid down in a single process, increasing the efficiency by using more of the incident sunlight. These tandem designs should be able to achieve 30% efficiency, compared with 10-20% for standard designs. Surprisingly, however, low efficiency solar cells can also have their place: dye-sensitised solar cell designs are currently 7-12% efficient, but can be produced using low cost roll to roll processing, so can still be cost competitive with high efficiency cells.
The key parameter for all solar installations is installed cost per watt delivered, and improvements in underlying solar conversion technologies are clearly going to help reduce this. There is healthy competition between conversion technologies, and every sign that efficiencies will continue to improve. However the installed cost depends on many factors, and the solar cell market, while long established, has many small companies who do not have the advantages of economies of scale and ability to take control of the whole supply and delivery chain. As the market matures we anticipate reductions in cost to come from novel business models as much as from technology.
Jeremy Bickerstaffe, Sagentia
Maxwell2
7 Comments
- 499 Days Ago
- 01/09/2012
Every day a new and different production method is reported to potentially lower ccst of retrofitting the roofs of the world and free us from the price whims of Big Oil. It needs to get cheaper and cheaper until a house can be way out away from the power net, and get enough electricity from sunlight to charge batteries for heating, cooling, water pumps and charge the batteries for electric cars so that a breakdown of power in the world will leave the solar cell house owners still comfortable,independent and growing greenhouse food and air.
That will take a lot of worry out of the possible breakdown of the electric power net, the worries of price of oil, war and weather damage to farms and roads and transport of food from far away to our family table. Mall sized buildings in hot desert areas can have roofs of solar cells that power air conditioning and condense water from the air and shelter each independent store inside as a family run live-in.a small town, buying each others products and services, hiring each other's children.independent of world market crashes. The world's deserts too hot now to occupy, will pay off any solar cell shade as the shade cools the ground shading and cooling acres of shady space for plants bushes small trees and fruits weather free.
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CapitalismPrevails
36 Comments
Combine this technique with another solar cell manufacturing technique
(http://www.technologyreview.com/energy/39314/page1) and the $/kwh should go down a lot.
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