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Posted: September 26, 2008
Patented Process Technology Drives New Generation of Inks
(Nanowerk News) Five Star Technologies, a leader in fine particle dispersions for functional inks, announced the availability of ElectroSperse™ S-series solar inks for use in crystalline silicon photovoltaic cells. Five Star's S-500 series, silver-based conductive inks, will allow solar cell makers to lay out front side grid lines as narrow as 80-100 microns -- much thinner than the 120-175-micron width of conventional contacts. The company's S-600 products -- low-bow, lead-free, aluminum-based pastes, intended for back surface field layers -- have been designed to co-fire at temperatures compatible with the S-500 silver inks and thus simplify the latter's adoption.
To be introduced at Solar Power International 2008 in San Diego on October 13-16, the inks are aimed at solving one of the most challenging issues facing solar cell performance: maintaining consistent electrical contact with emitter layers.
"Our customers are telling us that assurance of consistent contact could improve manufacturing yields significantly and boost overall cell efficiency by as much as one full percentage point," says Tim Fahey, Vice President, Business Development, of Five Star Technologies. "Our patented hydrodynamic cavitation process enables us to produce inks and pastes with unmatched silver and glass particle uniformity and particle sizes in the low to sub-micron range. That, in turn, gives users the ability to screen print much finer lines and to achieve more consistent emitter contact."
According to recent tests conducted by the Georgia Institute of Technology, monocrystalline cells produced with S-540 demonstrated:
The broader range of firing profiles, says Fahey, should help solve a common solar cell manufacturing problem. "Current commercial pastes have a narrow process window, and cell manufacturers quite often have to modify the firing profile for different lots of material due to inconsistent dispersion in traditional pastes," he says. "ElectroSperse inks and pastes are easily adaptable to individual user processing conditions."
Initial grades of the inks are intended for screen printing applications, but Five Star says it can control rheology to match a variety of printing processes, including non-contact dispensing approaches. For all processes, the ability to print finer dimensions should give cell designers greater flexibility in adding more efficient collection configurations.
About Five Star Technologies
Five Star Technologies is a supplier of high-performance dispersions, inks and pastes used in displays, photovoltaics and microelectronic packaging applications. Combining its patented hydrodynamic cavitation process with innovative chemistry, Five Star produces the ElectroSperse series of inks and pastes as well as a wide range of precision dispersions. ElectroSperse thick film conductor pastes are rheologically stable, easy-to-process materials, ideally suited for direct printing of fine features. Screen printable grades can be printed to features as small as 50 microns. Grades designed for extrusion and digital print processes are achieving even smaller print features, enabling replacement of thin film processing. Five Star is truly creating ... the future of functional inks.
For more information, please visit Five Star Technologies website at www.fivestartech.com.