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August 2009

 
Thin Film and Third Generation Solar Technology
First the solar paneled roofs. Now panels are going up on lawnmowers, stop signs, yard lights, backpacks, telephone poles, and cars. Despite the current recession, sales of solar panels were up 50% in 2008. This year sales volume is up while production costs are expected to drop 30%.1 Call it the new alternative energy fad, strongly promoted by new government spending initiatives, tax rebates, and green energy policies. Here in the Garden State, we have more solar installations per square mile than any other state. Only California leads New Jersey in the terms of capital spent on solar.2


Solar Cell Mounted on Utility Pole in New Jersey

Thin-film photovoltaic cells use less than 1% of the expensive silicon and light absorber materials compared with traditional (first generation) wafer-based solar cells. A thin-film solar cell is fabricated by depositing one or more layers of amorphous, photocrystalline, nanocrystalline silicon and other photovoltaic materials on a substrate. The thickness may vary from a few nanometers to tens of micrometers.3 Thin film cells (considered "second generation" technology) are less expensive to produce but still suffer from low efficiency.

Contact angle is used during various stages of thin film fabrication. Researchers at Georgia Institute of Technology have developed superhydrophobic surface treatments that not only improve light absorption but also enhance self-cleaning properties and promote runoff of dew and rainwater.4 Clean cells are significantly more efficient since less light is scattered by dust and dirt. 

The effort behind the newest solar technology, called third-generation, is to improve efficiency while keeping fabrication costs down. Non-semiconductor materials such as polymers, biomimetics, quantum dot technologies, tandem/multi-junction cells, hot-carrier cells, upconversion and downconversion technologies, and solar thermal technologies such as thermophotonics are being employed to innovate new methods for harnessing the sun's power.

Researchers at the University of Florida are working on organic solar cells that are low cost. To improve efficiency, the researchers are developing various surface treatments using N2 and O2 plasma and electron beam. Contact angle is used to quantify the effectiveness of the various treatments. With this technology, as the surfaces are made more hydrophilic, surface roughness diminishes and cell efficiency improves.5

In Spain, researchers are using contact angle to develop quantum dot sensitized solar cells.6 The method used for fabricating the cells requires a thin film of nanocrystals (also called "quantum dots") to be uniformly applied using a spin-coating process. Researchers at the US Department of Energy National Renewable Energy Laboratory have shown efficiency to be as high as 65%, which is about double the efficiency of today's best cells.7

Across the spectrum of photovoltaic cell development and production, from thin-film fabrication to cutting edge third-generation technologies, contact angle plays a critical role in the innovation of new materials and methods which will lead to better efficiency while lowering production costs and revolutionizing the solar energy market.

1 The New Surge in Solar, SmartMoney Magazine, July 13, 2009
2
New Jersey Outshines 48 of Its Peers in Solar Energy, The Wall Street Journal, July 31, 2009, p A5
3 Wikipedia, "Thin Film" and "Thin Film Solar Cell" articles, 2009
4 http://tinyurl.com/cl4xnz 
5 http://tinyurl.com/m7golj
6 http://tinyurl.com/nzzdkh; see PB23
7 http://tinyurl.com/mhcj43
 

Model 290 Reprise

In last month's newsletter we introduced the newest addition to our product line, the Model 290, the most automated product we currently offer. So far we have sold several of these systems and they have been met with enthusiasm by our customers. Naturally we are always pleased when a new product succeeds. Here are some of the compelling benefits of the Model 290:

1. Fully software-controlled dispensing for precise pendant and sessile drop formation as well as dynamic measurements with volume change; quick liquid change using our disposable tips.

2. Fully software-controlled tilting base for measuring advancing and receding contact angle as well as a contact angle hysteresis and roll-off angle.

3. DROPimage Advanced software which integrates the control of the camera, tilting base, and dispenser; includes a methods-based experiment design tool with options for specifying the phases, and controlling drop volume, time, events, and method parameters.

4. High-speed F1 series digital camera with the capacity to capture speeds of 60 frames per second at full resolution.

5. Proprietary backlight illuminator with powerful halogen source delivered cool via a fiber optic bundle.

6. Over 45 years of instrument design and manufacturing experience built into this and each product we sell.

For a quotation or more information on our Model 290 or any other ramé-hart instrument, please contact us.

 

Regards,

Carl Clegg
Director of Sales
Phone 973-448-0305
www.ramehart.com
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