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Some of the major advantages of residential solar panels include:

Solar cells are noise free. So they do not cause noise pollution. No need to worry about noice caused by solar panels.

Solar energy (solar power) harnessed by residential solar panels is non-polluting in nature. Unlike oil that leads to carbon-di-oxide and other carcinogens into air and other traditional power, solar energy cells are eco-friendly.

Solar cells require minimal maintenance by us.

The discovery that butterfly wings have scales that act as tiny solar collectors has led scientists in China and Japan in Asia to design a more efficient solar cell that could be used for powering homes, businesses, and other applications in the future.

In the study, Di Zhang of the State Key Lab of Metal Matrix Composites at Shanghai Jiao Tong University and colleagues note that scientists are searching for new materials to improve light-harvesting in so-called dye-sensitized solar cells, also known as Gratzel cells for inventor Michael Gratzel. These cells have the highest light-conversion efficiencies among all solar cells - as high as 10%.

"The spot price of silicon materials in China will drop to US$50/kg within 2009," said Dylen Liu of JL McGregor & Company, a research firm in China.

Dylen Liu of JL McGregor & Company delivered a speech on the Chinese solar cell industry at Solar Cell Market Seminar 2009 hosted by Nikkei Market Access with help from Nikkei Microdevices in Japan.

In Dylen Liu's speech, he introduced recent drops in the spot price of polycrystalline silicon materials in China. The price was more than US$350/kg until October 2008, but dropped by half in November 2008, being hit by the financial crisis and other issues. And the price continued to fall to less than US$80/kg in April 2009.

Liu of JL McGregor & Company forecast that the spot price will further decline to US$50/kg within 2009. And he calculated the manufacturing cost of a crystalline silicon solar cell module when the price of polycrystalline silicon materials is US$50/kg. The cost will be US$1.1 to 1.2/W at vertically integrated solar cell manufacturers in China, he said.

China Sunergy Co. Ltd. announced that it has entered into a wafer purchase agreement and a solar cell sales agreement with an unnamed U.S.-based photovoltaic (PV) products firm.

China Sunergy Co. Ltd. will use the multi-silicon wafers purchased from the firm to produce multi-silicon solar cells, which will then be sold back to the firm for incorporation into its downstream solar products. Based on the forecast provided by the U.S. based manufacturer, a total of 20 – 25 megawatts (MW) of solar cells will be supplied by China Sunergy throughout 2009.

t's expected that the power generation cost of thin-film solar cells would approach grid parity in 2012, and crystal silicon cells would reach the target in 2020.

Now, the installation cost for crystal silicon solar power (OTCBB:SOPW) stations stands at RMB20.00/watt while that for thin-film one is about RMB12.00yuan/watt. Thin film solar cell is cheaper.

Industry insider said that thin-film solar cells generated 10 percent more electricity than that of crystal silicon cells.

Chinese solar product makers like SunTech Power Holdings Co., Ltd. (NYSE:STP) (STP.NYSE), Astronergy Solar, Best Solar and Baoding Tianwei Solar Film Company plans to realize mass production of thin-film solar cells within 2009.

China recently released a subsidy scheme on solar rooftop projects providing RMB20 yuan/watt-peak subsidies for solar PV power projects with single installed capacity exceeding 50 kWp.

In recent years, Solar industry in China had witnessed a rapid development. China's solar cell output only accounted for 8.1% of the total global output in 2005, but the ratio sharply increased to 17.1% in 2006. And in 2007, Solar cell output in China was totaled at 1,088MWp, accounting for 27.2% of the total global output, becaming the largest solar cell manufacturing country in the world.

Unlike the normal solar cell, the manufacturing of thin-film solar cell is not affected by the lack of raw materials such as polysilicons. Therefore, it attracted more attentions, especially from China. China's thin-film solar cell output increased sharply during the period of 2007 to 2008.

As before, thin film solar cells are laminated to produce a weather resistant and environmentally robust module. Although they are less efficient (production modules range from 5 to 8%), thin films are potentially cheaper than c-Si because of their lower materials costs and larger substrate size.

However, some thin film materials have shown degradation of performance over time and stabilized efficiencies can be 15-35% lower than initial values. Many thin film technologies have demonstrated best cell efficiencies at research scale above 13%, and best prototype module efficiencies above 10%. The technology that is most successful in achieving low manufacturing costs in the long run is likely to be the one that can deliver the highest stable efficiencies (probably at least 10%) with the highest process yields.

Amorphous silicon is the most well-developed thin film technology to-date and has an interesting avenue of further development through the use of "microcrystalline" silicon which seeks to combine the stable high efficiencies of crystalline Si technology with the simpler and cheaper large area deposition technology of amorphous silicon.

The high cost of crystalline silicon wafers (crystalline silicon wafers make up 40-50% of the cost of a finished module) has led the industry to look at cheaper materials to make solar cells.

Thin film technologies are all complex. They have taken at least twenty years, supported in some cases by major corporations in the industry, to get from the stage of promising research (about 8% efficiency at 1 cm2 scale) to the first manufacturing plants producing early product.

Amorphous silicon is the most well developed of this thin film technologies. In its simplest form, the cell structure has a single sequence of p-i-n layers. Such cells suffer from significant degradation in their power output (in the range 15-35%) when exposed to the sun.

Crystalline silicon (c-Si) has been used as the light-absorbing semiconductor in the most solar cells, even though it is a relatively poor absorber of light and requires a considerable thickness (several hundred microns) of material. Nevertheless, crystalline silicon (c-Si) has proved convenient because it yields stable solar cells with good efficiencies (11-16%, half to two-thirds of the theoretical maximum) and uses process technology developed from the huge knowledge base of the microelectronics industry.

Two types of crystalline silicon are used in the industry.

The first type of crystalline silicon is monocrystalline (single crystal), produced by slicing wafers (up to 150mm diameter and 350 microns thick) from a high-purity single crystal boule.

The second is multicrystalline (Polycrystalline) silicon, made by sawing a cast block of silicon first into bars and then wafers. The main trend in crystalline silicon cell manufacture is toward multicrystalline technology.

Three key elements in a solar cell form the basis of their manufacturing technology.

The first key element in a solar cell is the semiconductor, which absorbs sunlight and converts it into electron-hole pairs.

The second in a solar cell is the semiconductor junction, which separates the photo-generated carriers (electrons and holes).