CdTe Research at CSU
The CdTe research was initiated in the Materials Engineering Laboratory, also known as Photovoltaic Manufacturing Laboratory, in 1991. The vision of the research was to create a manufacturing technology as large-scale and continuous as aluminum can production. After examination of numerous materials, cadmium telluride thin-film photovoltaics was found to be a very promising technology. The material is much less sensitive to impurities and requires fewer costly processing steps than conventional crystalline silicon photovoltaics.
In the past two decades at CSU’s Next Generation PV Center, Dr. W.S. Sampath and his research associates, Al Enzenroth and Kurt Barth along with several graduate and undergraduate students have persistently investigated and eliminated obstacles to the mass production of CdTe photovoltaics. Their research accomplishments include:
(i) A back surface electrical contact for CdTe solar cells via a highly controlled introduction of copper into the device, an innovation provided a way to create high efficiency devices suitable for more than 20 years of operation outdoors;
(ii) A continuous, inline, scalable manufacturing process in which all processes occur in one vacuum chamber, thus significantly lowering manufacturing costs through lower capital equipment costs, improved material utilization (up to 95%), and rapid production cycles; and
(iii) A method for encapsulating the finished modules that is more weather-resistant and ten times faster than existing methods.
The research at NGPV has contributed directly and significantly to the massive growth of the CdTe PV industry. CdTe PV is the lowest cost photovoltaic technology—in some cases cost-competitive with fossil fuel electricity production without government subsidy. These advances have directly enabled CdTe photovoltaics to become the leading PV technology in the US and the fastest growing PV technology in the world.
Abound Solar, was spun out of CSU’s Photovoltaic Manufacturing Laboratory. During 2007 to 2012 the module prices declined from $3.50/watt to $0.75/watt primarily due to unfair subsidy from the Chinese Government. The US Department of Commerce and the International Trade Association has found China to have unfairly subsidized their PV industry causing harm to US PV industry. This led to loss of interest from the investors and finally Abound had to cease operations in July 2012. The IP of Abound Solar has been acquired by Colorado State University and will form the basis of further advancing the CdTe technology.
In 2009 NSF awarded the Industry/University Co-Operative research center on Next Generation Photovoltaics to CSU with Dr. W.S. Sampath as the Site Director. The industrial members of the center include: First Solar, the leading manufacturer of CdTe modules and 5N Plus, the leading producer of CdTe.
- Research projects sponsored by NSF, DOE, EPA, USAID that form collaborations between industry and academic partners
- Active member of the National CdTe R&D team and participant in local professional societies
- Technology developed adopted by Abound Solar and First Solar
- Participant in Commercialization Planning Workshop for Research Personnel, Mohawk Research
- Development of prototyping equipment for rapid manufacturing of photovoltaics
- Graduate Degrees: 22 graduate students have completed 25 graduate degrees; Post-Doctoral Fellows Sponsored: 3; 6 undergraduate engineering students currently support the research and gain valuable experience.