School of Illinois Researchers Show Us Little Known Solutions to Make More Economical Photo voltaic panels
June 7, 2010 by
Filed under Solar Basics
Even if silicon is actually the market normal semiconductor in the majority of electric devices, including the photovoltaic cells that pv panels utilize to transform sunshine into electricity, it is not really the most effective component on the market. For example, the semiconductor gallium arsenide and related compound semiconductors provide close to two times the effectiveness as silicon in solar units, but they are rarely employed in utility-scale applications because of their high production cost.
U. of Illinois. (http://illinois.edu/) professors J. Rogers and X. Li investigated lower-cost methods to manufacture thin films of gallium arsenide that also allowed adaptability in the types of devices they can be integrated into.
If you may minimize substantially the cost of gallium arsenide and some other compound semiconductors, then you might increase their variety of applications.
Typically, gallium arsenide is transferred in a single thin layer on a little wafer. Either the preferred device is created specifically on the wafer, or the semiconductor-coated wafer is break up into chips of the desired size. The Illinois group decided to put in multiple layers of the material on a single wafer, producing a layered, “pancake” stack of gallium arsenide thin films.
If you grow ten levels in 1 growth, you simply have to load the wafer 1 time. If you do this in ten growths, loading and unloading with temperature ramp-up as well as ramp-down take a lot of time. If you take into account what is required for every growth – the machine, the preparation, the period, the people – the overhead saving this solution provides is a substantial cost decrease.
Following the scientists individually peel off the layers and shift them. To accomplish this, the stacks swap layers of aluminum arsenide with the gallium arsenide. Bathing the stacks in a formula of acid and an oxidizing agent dissolves the levels of aluminum arsenide, freeing the single thin sheets of gallium arsenide. A soft stamp-like device selects up the layers, just one at a time from the top down, for shift to one more substrate – glass, plastic or silicon, based on the application. After that the wafer could be used again for one more growth.
By performing this it’s possible to make much more material more rapidly and more cost effectively. This process could make bulk quantities of material, as compared to simply the thin single-layer method in which it is typically grown.
Freeing the material from the wafer also opens the opportunity of flexible, thin-film electronics made with gallium arsenide or additional high-speed semiconductors. To make devices that could conform but still retain high efficiency, that’s considerable.
In a document shared online May twenty in the journal Nature (http://www.nature.com/), the team describes its techniques and displays three types of units making use of gallium arsenide chips made in multilayer stacks: light devices, high-speed transistors and photo voltaic cells. The authors additionally provide a detailed cost comparison.
Another advantage of the multilayer method is the release from area constraints, particularly crucial for photo voltaic cells. As the layers are taken out from the stack, they can be laid out side-by-side on one more substrate in order to produce a much larger surface area, whereas the typical single-layer process limits area to the size of the wafer.
For photovoltaics, you want large area coverage to catch as much sunshine as achievable. In an extreme situation we may grow adequate layers to have 10 times the area of the standard.
Up coming, the team programs to investigate more potential device applications and additional semiconductor materials that could adapt to multilayer growth.
About the Writer – Shannon Combs is currently writing for the residential solar power grants web site, her personal hobby website centered on guidelines to help home owners to save energy with sun power.
How Does Solar Power Work?
May 12, 2010 by
Filed under Solar Basics
The basics of solar power:
Solar power is probably the cleanest, most viable form of renewable energy available and it can be used in several forms to help power your house. Many gardens now use solar lights or solar garden water features. The availability and wide use of solar power in gardens shows exactly how versatile it is as a source of energy. The technology and the systems are becoming smaller, more compact and better looking than when they were first created and used. Early examples of solar power systems can be seen in California where, in the 1980s, enough solar power panels were installed to power over 10 million homes.
How do photovoltaic tiles work?
Simply put photovoltaic tiles and other forms of solar energy work by converting some of the energy in sunlight into a clean form of electricity that can be used in our houses. The PV cells consist of a positive and a negative slice of silicon placed under a thin slice of glass. As the protons of the sunlight beat down onto the PV cell they knock the neutrons off the silicon. The negatively charged free neutrons are attracted to the silicon but are trapped by the magnetic field that is formed from the opposing fields. Small wires on the silicon catch these neutrons and when connected in a circuit an electric current is formed.
This reaction gives Direct Current electricity though, and it must be passed through an inverter to be converted into an Alternating Current used in our homes to power any electrical items. Some of the power is lost in this part of the process as the inverter is only around 95% efficient but this is a much greater efficiency than was once available.
The nature of the PV cell means there is little or no maintenance required and there are no moving parts; this means that a typical PV cell can last up to 40 years with no work besides an annual clean.
How can I use them to power my house?
There are several ways to use solar power around the house and not just for powering. You can use it to heat your hot water, heat your pool or even your central heating or if you have plenty of roof space and a reasonable amount of sun you can get a grid tie system; a grid tie system means that not only can you power your entire house but during those times when you create an excess of electricity you can sell it back to the grid. An efficiently solar powered home will be able to reasonably create between 75 and 100% of their own power and because of the grid tie system this means you may not have to pay for electricity ever again.
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