10-05/06 :: May/June 2010

nanotimes News in Brief

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Solar Cells // Nanoscale Coax Solves ‘Thick & Thin’ Solar Cell Dilemma

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hysicists at Boston College found a way to resolve the “thick & thin” challenge through a nanoscale

solar architecture based on the coaxial cable, a radio technology concept that dates back to the first trans- Atlantic communications lines laid in the mid 1800s.

“Many groups around the world are working on nanowire-type solar cells, most using crystalline semiconductors,” said co-author Michael Naughton, a professor of physics at Boston College. “This nano- coax cell architecture, on the other hand, does not require crystalline materials, and therefore offers promise for lower-cost solar power with ultrathin absorbers. With continued optimization, efficiencies beyond anything achieved in conventional planar architectures may be possible, while using smaller quantities of less costly material.”

Optically, the so-called nanocoax stands thick en- ough to capture light, yet its architecture makes it thin enough to allow a more efficient extraction of current, the researchers report in PSS‘s Rapid Re- search Letters. This makes the nanocoax, invented at Boston College in 2005 and patented last year, a new platform for low cost, high efficiency solar power. Constructed with amorphous silicon, the nanocoax cells yielded power conversion efficiency in excess of 8%, which is higher than any nanostruc- tured thin film solar cell to date, the team reported. The ultra-thin nature of the cells reduces the Sta- ebler-Wronski light-induced degradation effect, a

© Boston College

major problem with conventional solar cells of this type, according to the team, which included Boston College Professors of Physics Krzysztof Kempa and Zhifeng Ren, as well as BC students and collabora- tors from Solasta Inc., of Newton, Mass., and École Polytechnique Fédérale de Lausanne, Institute of Microengineering in Switzerland. The research was funded in part by a Technology Incubator grant from the Department of Energy.

M. J. Naughton, K. Kempa, Z. F. Ren, Y. Gao, J. Rybczynski, N. Argenti, W. Gao, Y. Wang, Y. Peng, J. R. Naughton, G. McMahon, M. J. Burns, A. Shepard, M. Clary, C. Ballif, F.- J. Haug, T. Söderström, O. Cubero, C. Eminian: Efficient nanocoax-based solar cells, In: physica status solidi (RRL) - Rapid Research Letters AOP, June 8, 2010, Pages 181-183 DOI:10.1002/pssr.201004154: http://dx.doi.org/10.1002/pssr.201004154 http://www.physics.bc.edu/Deptsite/index.shtml