Scientists at Natcore Technology Inc., in collaboration with researchers at Rice University, have successfully fabricated the first inorganic flexible thin film solar cell by solution processes without the use of high-temperature semiconductor processing.
Natcore has replaced traditional thermal vacuum processes, such as CVD and PECVD (chemical vapor deposition, plasma enhanced chemical vapor deposition) for making solar cells with its liquid phase deposition (LPD) wet chemistry process.
The company’s LPD process technology is aimed at enabling silicon solar cell manufacturers to reduce silicon usage by over 60 percent and raise efficiency yields to 30 percent over conventional solar cells that yield some 17 percent efficiency, according to the company.
Using the LPD process, a cadmium/selenium (CdSe) absorber layer was grown on a single-walled carbon nanotube (SWNT)-derived back contact substrate. LPD was also used to grow a copper/selenium (CuSe) window layer onto which silver contacts were deposited. The resulting photovoltaic device shows a characteristic IV curve that confirms the potential for this process to form a flexible solar cell.
The work showing the IV curve was reported in a recent issue of the journal Physical Chemistry Chemical Physics.
"This is a major step forward in our goal of creating a low cost flexible solar cell," said Rice Professor Andrew R. Barron, a Natcore co-founder. "These results demonstrate the feasibility of our approach. This is the first step in moving this towards a commercial cell."
"This is a most important milestone along the way to a low-cost flexible solar cell," said Natcore's CEO and President Chuck Provini.
Provini said the researchers have shown the feasibility of using LPD to grow a whole cell on a flexible substrate that remains flexible even with all of the layers. “If we can marry this development with our multi-junction tandem solar cell technology, we'll have a truly world-changing event,” added Provini.
The technology should be adaptable to the production of roll-to-roll solar cells, according to Provini. “That has been in our plans since we established our R&D Center in proximity to a former Kodak roll-to-roll photo film plant."
Provini said that to improve the quality and efficiency of the cell the work will be moved from the lab at Rice to Natcore’s lab in Rochester, NY. “If we had adequate funds and adequate manpower, we could have a commercial-quality cell within a year.”
Headquartered in Red Bank, NJ, Natcore is the exclusive licensee of Rice University’s thin-film growth technology.