February 14, 2012Material from Sumitomo Chemical Employed in UCLA’s Tandem Polymer
Photovoltaic Cell Achieving Power Conversion Efficiency of 10.6%
A polymer photovoltaic cell produced by Professor Yang Yang at the University ofCalifornia, Los Angeles (UCLA) that employs a material developed by Sumitomo
Chemical has achieved a power conversion efficiency of 10.6%, as certified by the U.S.
Department of Energy’s National Renewable Energy Laboratory (NREL). NREL, theU.S. Department of Energy's primary national laboratory for renewable energy andenergy efficiency research and development, is one of the few institutions in the world
capable of evaluating and officially certifying the performance of solar cells. The
efficiency of 10.6% ranks the world's top level among polymer photovoltaic cells that areavailable at the moment.
Because of their lightweight, thin and flexible nature, polymer photovoltaic cells areexpected to play a significant role in the development of the next generation solar cell
technology. With a special printing process, large surface area cells can be manufactured
in quick succession, which, in turn, is expected to attain lower production cost incomparison to silicon solar cells that are currently the dominant technology in use.
The newly-developed polymer photovoltaic cell employs a tandem cell architecture,
which, by bringing together two photoelectric conversion layers with different absorption
bands, enables a broader spectrum of solar energy to be utilized, thereby delivering
higher conversion efficiency compared to single-layer solar cells. On the other hand, theperformance of the polymer photovoltaic cell considerably depends on the combinationof the materials with different absorption bands as well as the material used as aninterlayer. The power conversion efficiency of 10.6% has been achieved by combining ashort-wavelength absorption material and an interlayer material capable of minimizing
electrical loss, that were developed by UCLA, with a highly-efficient long-wavelength
absorption material developed by Sumitomo Chemical.
Sumitomo Chemical is promoting the development of polymer photovoltaic cells bycapitalizing on the polymer organic light emitting diode (PLED)-related technology fordisplays and lighting applications that the Company has been working on vigorously forcommercialization. In each of PLEDs and polymer photovoltaic cells, conjugatedpolymer (*) holds the key to greater materials efficiency. As the Company engages in thisundertaking, it has the distinctive advantage of its superior expertise to utilize thepolymer material design and synthesis technologies the Company has long cultivatedthrough the development of PLED materials and devices. When the Company is tomanufacture polymer photovoltaic cells in large quantity in the future, the PLED material
production facilities it owns will offer another great advantage.
Going forward, Sumitomo Chemical will further strengthen development of enhancedperformance materials, while working with UCLA and building on its own technologicalstrength. The Company seeks to bring its high-conversion efficiency for polymer
photovoltaic cells to a commercially viable level as early as possible. By leveraging thespecific advantages of polymer photovoltaic cells, the Company will initially target suchapplications as battery chargers for mobile devices, including mobile phones andnotebook PCs, or those products that are integrated into indoor walls or transparent
windowpanes. In the future, the Company will aim to expand the applications to include
such fields as household rooftops and power generation for industrial use by further
improving conversion efficiency and durability of the cells.
(*) Conjugated polymer: A polymer with alternating single and double bonds. In addition
to being organic, conjugated polymers exhibit conductivity.