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Posted: Aug 14th, 2012
University of Arkansas Employs Talysurf Profiler to Develop Next Generation of Photovoltaic Cells
(Nanowerk News) Researchers at the University of Arkansas at Fayetteville are utilizing the Talysurf CCI Lite optical 3D profiler from AMETEK Taylor Hobson to measure next-generation photovoltaic cells made from lower-cost materials that offer substantially improved energy conversion efficiencies.
The Optoelectronics Research Lab at the University of Arkansas, under the direction of Electrical Engineering Professor Omar Manasreh, has successfully fabricated advanced solar energy cells with light-to-energy conversion efficiencies 50% greater than the current-generation of silicon-based solar cells. Among the most important instruments in the University’s state-of-the-art lab is the Taylsurf CCI Lite non-contact optical 3D profiler. The Optoelectronic Research Lab has received funding by the US Air Force Office of Scientific Research, NASA-EPSCoR Program and NSF-EPSCoR Program.
“The Talysurf CCI profiler has been critical to our success in fabricating highly efficient devices by providing our researchers with accurate information on the precise depths and dimensions of the surface characteristics of these advanced photovoltaic cells,” notes Professor Manasreh.
“Current silicon-based solar energy technology results in solar cells with a light-to-energy conversion efficiency of no greater than 23 percent,” he adds. “The advanced cells our researchers have developed offer energy conversion efficiencies that are 50 percent greater than those of silicon-based cells. The ultimate goal of this research is to create solar cells with energy conversion efficiencies approaching the theoretical values.”
The University of Arkansas has employed two novel approaches in fabricating advanced solar energy devices. The first approach uses a combination of copper, indium, gallium and selenium (CuInSe2 and CuInGaSe2) to grow nanocrystals that are made functional by generating volatile ligands—molecules that bind to a central atom. The nanocrystals are then either converted into thin films or combined with titanium dioxide or zinc oxide nanotubes to create solar cells that are tested and evaluate for their energy efficiency.
The second approach uses molecular beam epitaxy, a method of depositing nanocrystals, to create quantum dots made of indium arsenide (InAs). Quantum dots are nano-sized particles of semiconductor material. To enhance the performance of the solar cells, researchers use short ligands to couple metallic nanoparticles to the nanocrystals and quantum dots. The researchers then investigate the plasmonic effect of trapping sun light, which in turn increases the device’s energy conversion efficiency. Other approaches are directed toward investigating iron pyrite solar cells.
The Talysurf CCI Lite has proven highly valuable in conducting this advanced solar energy research. The instrument utilizes Coherence Correlation Interferometry, a Taylor Hobson-patented technique, to provide both long scan ranges and high-resolution surface measurement with a single mode of operation. The result is a non-contact 3D surface texture, step height and micro-dimensional measurement system that can provide results in seconds.
The sensitivity of the coherence correlation algorithm to low-light levels adds to the versatility of the instrument. All types of rough, smooth or highly reflective materials, including glass, metal, photoresist, polymer, liquid inks and pastes, can be measured without difficulty. Careful design and construction of the Talysurf CCI Lite assures stability throughout the measuring loop, an important requirement for high-precision metrology. The instrument’s compact footprint also makes it ideal for laboratory use.
The Talysurf CCI Lite comes standard with a high-sensitivity 1-million-pixel image sensor for excellent data resolution in the X and Y axis. This combined with a very low missing data rate results in class-leading surface detail.
The instrument offers a number of features not typically found on tabletop systems, including automatic pattern measurement, X and Y stitching and Z stitching. Detailed measurement and analysis can be carried out automatically with the press of a button. Surface features defined by diameter, area or volume can be automatically identified, measured and sorted. Internationally recognized waviness and roughness parameters in both 3D and 2D are included.
Taylor Hobson is an ultra-precision technology company operating at the highest levels of accuracy within the field of surface and form metrology, providing contact and non-contact measurement solutions for the most demanding industrial and research applications. It is a unit of AMETEK, Inc, a leading global manufacturer of electronic instruments and electromechanical devices with annual sales of more than $3.0 billion. www.taylor-hobson.com