Thin film solar cells

**greencat** · #1 06-24-2009, 02:45 AM

Thin film solar cells is likely the next generation solar cells for the home use. Light weight and easy to install it will merit serious contention with home owners since they can be placed in just about any location.

While not acheiving the same eletrical output as traditional solar cells, they make-up for it in cost and application.

A Thin-Film Solar Cell (TFSC), also called a Thin-Film Photovoltaic Cell (TFPV), is a solar cell that is made by depositing one or more thin layers (thin film) of photovoltaic material on a substrate. The thickness range of such a layer is wide and varies from a few nanometers to tens of micrometers.

Many different photovoltaic materials are deposited with various deposition methods on a variety of substrates. Thin Film Solar Cells are usually categorized according to the photovoltaic material used.

Thin-film photovoltaics cells are included in the TIME's Best Inventions of 2008

**greencat** · #2 06-27-2009, 10:55 AM

Quote:

Originally Posted by greencat

Thin film solar cells is likely the next generation solar cells for the home use. Light weight and easy to install it will merit serious contention with home owners since they can be placed in just about any location.

While not acheiving the same eletrical output as traditional solar cells, they make-up for it in cost and application.

A Thin-Film Solar Cell (TFSC), also called a Thin-Film Photovoltaic Cell (TFPV), is a solar cell that is made by depositing one or more thin layers (thin film) of photovoltaic material on a substrate. The thickness range of such a layer is wide and varies from a few nanometers to tens of micrometers.

Many different photovoltaic materials are deposited with various deposition methods on a variety of substrates. Thin Film Solar Cells are usually categorized according to the photovoltaic material used.

Thin-film photovoltaics cells are included in the TIME's Best Inventions of 2008

Thin film solar panels are a newer, thinner type of solar panel that has the potential to make solar energy much more affordable. They rely on the same photovoltaic process that "thick" solar panels use. Put simply, the PV cell contains semiconductor material. Sunlight passes through and interacts with the semiconductor material, and creates an electric current. This electricity can be used immediately to power appliances in your home or business, or stored in batteries for later use.

So what's so great about thin film solar panels? Well, thick solar panels (the first generation of solar panels, and the ones you are used to seeing), traditionally use crystalline silicon for the semiconductor material. It works as a way to create electricity from sunlight, but it's labor-intensive to manufacture. Each cell has to be produced on an individual silicon wafer, one by one, which makes it expensive. This is the main reason that solar panels have not been widely affordable in the past.

But thin film solar panels use materials for their semiconductors that are much thinner than crystalline silicon. The "thin film" semiconductors can be mass produced using automated systems and cheaper materials. At this point, the process is almost 3 times less labor-intensive than the process for manufacturing the traditional crystalline silicon thick cell solar panels. So the cost to manufacture solar panels is coming down. This means it will be cheaper for new start-up businesses to enter the solar panel manufacturing market. And as more businesses produce and supply solar panels, prices will drop even further.

The "thin film" process also means that the solar cell is smaller, lighter weight, and can be applied to materials that are smaller, lighter weight and more flexible themselves. In fact, "thin film" technology has changed the look of solar panels so much that you might not recognize them. Instead of needing a heavy and elaborate steel structure to hold a large array of thick silicon-based solar panels in place, the thin film solar panels can be integrated into the roof or wall itself.

Thin film composition roofing shingles and thin film panels for metal roofing are already commercially available and being used in construction. Smaller portable solar panel systems are being manufactured to power up your electronic devices. Cell phones, GPS devices, MP3 players and even televisions and laptops can now be powered with thin film solar technology. These portable thin film solar panels are small enough and light weight enough that you can "install" one on your backpack or carry one in your purse.

LordofLightAZ · #3 06-28-2009, 03:33 PM

I've seen the backpacks advertised. I think if the price is right then a lot of people will be willing to use the product. Along the line of backpacks, it would be cool if bike saddlebag tops had them to charge batteries for lights, or even a nice little cooler to hold "pop". Umbrellas, with LED lights is another winner, I know they make them with the rigid panels now, but image if the umbrella was covered with the stuff. Another serious application would be bus stop roofs, for both cooling fan and night lighting.

vcm1376 · #4 06-28-2009, 06:10 PM

Where can I buy such a solar panel? Are they flexible so I can roll it up? I am interested in learning more about these.

**greencat** · #5 06-28-2009, 07:29 PM

Quote:

Originally Posted by vcm1376

Where can I buy such a solar panel? Are they flexible so I can roll it up? I am interested in learning more about these.

Nanosolar SolarPly™.
Light-weight solar-electric cell foil which can be cut to any size. Non-fragile. No soldering required for electrical contact.

Available wholesale to strategic partners.

Benefits? World's lowest-cost solar panel. Designed to halven the balance-of-system cost relative to competitive panels. 25-year warranty.

Want to Buy Panels? We are presently already sold out for the next 12 months. We are working hard to scale our production capacity as fast as possible.

I will continue to look and see what I can find.

vcm1376 · #6 06-29-2009, 04:24 AM

Thank you for that. I have also been doing some research and found some. These have to be soldered, but they look good. They are sold on robotshop.com and they are called powerfilm®.

My idea was to use these to increase the range on an electric bicycle. This is only an idea right now because I don't have the money to run out and buy an electric bicycle right now. I will be looking into it in the near future though. What I spend on the bicycle and the solar panels, (panels look very inexpensive), will be saved many times over in the gas I don't have to purchase to drive to and from work.

**greencat** · #7 07-30-2009, 11:58 AM

Thin-layer Solar Cells May Bring Cheaper Green Power
— Scientists are researching new ways of harnessing the sun's rays which could eventually make it cheaper for people to use solar energy to power their homes.

The experts at Durham University are developing light-absorbing materials for use in the production of thin-layer solar photovoltaic (PV) cells which are used to convert light energy into electricity.

The four-year project involves experiments on a range of different materials that would be less expensive and more sustainable to use in the manufacturing of solar panels.

Thicker silicon-based cells and compounds containing indium, a rare and expensive metal, are more commonly used to make solar panels today.

The research, funded by the Engineering and Physical Sciences Research Council (EPSRC) SUPERGEN Initiative, focuses on developing thin-layer PV cells using materials such as copper indium diselenide and cadmium telluride.

Right now the project is entering a new phase for the development of cheaper and more sustainable variants of these materials.

The Durham team is also working on manipulating the growth of the materials so they form a continuous structure which is essential for conducting the energy trapped by solar panels before it is turned into usable electricity. This will help improve the efficiency of the thin-layer PV cells.

It's hoped that the development of more affordable thin-film PV cells could lead to a reduction in the cost of solar panels for the domestic market and an increase in the use of solar power.

Solar power currently provides less than one hundredth of one percent of the UK's home energy needs.

The thin-layer PV cells would be used to make solar panels that could be fitted to roofs to help power homes with any surplus electricity being fed back to The National Grid.

This could lead to cheaper fuel bills and less reliance on burning fossil fuels as a way of helping to generate electricity.

Professor Ken Durose, Director of the Durham Centre for Renewable Energy, who is leading the research, said: "One of the main issues in solar energy is the cost of materials and we recognise that the cost of solar cells is slowing down their uptake.

"If solar panels were cheap enough so you could buy a system off the shelf that provided even a fraction of your power needs you would do it, but that product isn't there at the moment.

"The key indicator of cost effectiveness is how many pounds do you have to spend to get a watt of power out?

"If you can make solar panels more cheaply then you will have a winning product."

To aid its research the university has taken delivery of a £1.7 million suite of high powered electron microscopes, funded by the Science Research Investment Fund, which have nano-scale resolution allowing scientists to see the effects that currently limit the performance of solar cells.

One of the microscopes is the first of its kind in the UK and Professor Durose said: "This instrument will put the North East right out in front.

"We are working on new ideas in renewable energy and this opens up tremendous opportunities in research."

**greencat** · #8 07-30-2009, 12:01 PM

Solar energy could become more affordable following a breakthrough by UNSW scientists, who have boosted the efficiency of solar cell technology. The advance could see the price of an installed solar system for an average house fall from around $20,000 to $15,000. Up to 45 percent of the cost of solar cell technology is due to the high cost of the silicon used to convert sunlight to electricity.

Silicon is the material of choice in the electronics industry because of its stability, non-toxicity and ubiquity. However, silicon is a poor absorber of light. In a bid to drive down costs, scientists have moved from using expensive thick silicon “wafers” to cheaper “thin film” cells, containing less silicon.

The disadvantage of these one-to-two micron-thick films is that they convert only eight to 10 percent of incoming sunlight into electricity, compared to the 25 percent efficiency of thicker, more expensive, silicon wafers. Scientists around the world are testing new ways to boost the efficiency of thin film technology, while keeping down costs.

Now, researchers at UNSW’s ARC Photovoltaics Centre of Excellence, led by PhD student Supriya Pillai have reported a 16-fold enhancement in light absorption in 1.25-micron thin-film cells for light with a wavelength of 1050 nm. They have also reported a seven-fold enhancement in light absorption in the more expensive wafer type cells light wavelengths of 1200 nm.

"Most thin-film solar cells are between eight and 10 percent efficient," says Dr Kylie Catchpole, a co-author of the study, "but the new technique could increase efficiency to between 13 and 15 percent."

That's an important advance, she says: "If they're below 10 percent efficient, then you can't really afford to install them, because it would take up too much of your roof area, for example, to power your house." Once the technology approaches 15 per cent efficiency, it becomes commercially viable.

An average house could have its daily power supplied by installing a solar system and panels covering 10 square metres. This system would exclude power for cooking and hot water heating.

The breakthrough, which is reported in the upcoming issue of the Journal of Applied Physics, could eventually see a dramatic rise in solar power’s share of the electricity market. Currently only 30,000 Australian households - out of 8 million - have installed solar panels.

The UNSW researchers have devised a way to deposit a thin film of silver (about 10 nanometres thick) onto a solar cell surface and then heat it to 200° Celsius. This breaks the film into tiny 100-nanometre “islands” of silver that boost the cell’s light trapping ability, thereby boosting its efficiency.

**greencat** · #9 07-30-2009, 12:05 PM

Physicist Bram Hoex and colleagues at Eindhoven University of Technology, together with the Fraunhofer Institute in Germany, have improved the efficiency of an important type of solar cell from 21.9 to 23.2 percent (a relative improvement of 6 per cent). This new world record is being presented at a major solar energy conference in San Diego.

The efficiency improvement is achieved by the use of an ultra-thin aluminum oxide layer at the front of the cell, and it brings a breakthrough in the use of solar energy a step closer.

An improvement of more than 1 per cent (in absolute terms) may at first glance appear modest, but it can enable solar cell manufacturers to greatly increase the performance of their products. This is because higher efficiency is a very effective way of reducing the cost price of solar energy. The costs of applying the thin layer of aluminum oxide are expected to be relatively low. This will mean a significant reduction in the cost of producing solar electricity.

Ultra-thin

Hoex was able to achieve the increase in efficiency by depositing an ultra-thin layer (approximately 30 nanometer) of aluminum oxide on the front of a crystalline silicon solar cell. This layer has an unprecedented high level of built-in negative charges, through which the -- normally significant -- energy losses at the surface are almost entirely eliminated. Of all sunlight falling on these cells, 23.2 per cent is now converted into electrical energy. This was formerly 21.9 per cent, which means a 6 per cent improvement in relative terms.

Dutch company OTB Solar

Hoex gained his PhD last week at the Applied Physics department of the TU/e with this research project. He was supported in the Plasma & Materials Processing (PMP) research group by professor Richard van de Sanden and associate professor Erwin Kessels. This group specializes in plasma deposition of extremely thin layers. The Dutch company OTB Solar has been a licensee of one of these processes since 2001, which it is using in its solar cell production lines. Numerous solar cell manufacturers around the world use equipment supplied by OTB Solar.

The ultra-thin aluminum oxide layer developed in the PMP group may lead to a technology innovation in the solar cell world. A number of major solar cell manufacturers have already shown interest.

Promising

Solar cells have for years looked like a highly promising way to partly solve the energy problem. The sun rises day after day, and solar cells can conveniently be installed on surfaces with no other useful purpose. Solar energy also offers opportunities for use in developing countries, many of which have high levels of sunshine. Within ten to fifteen years the price of electricity generated by solar cells is expected to be comparable to that of 'conventional' electricity from fossil fuels.

This technology breakthrough now brings the industrial application of this type of high-efficiency solar cell closer

lilypotter · #10 08-28-2009, 12:50 PM

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