Title :
Ultrathin Flexible Crystalline Silicon: Microsystems-Enabled Photovoltaics
Author :
Cruz-Campa, Jose L. ; Nielson, Gregory N. ; Resnick, Paul J. ; Sanchez, Carlos A. ; Clews, Peggy J. ; Okandan, Murat ; Friedmann, Tom ; Gupta, Vipin P.
Author_Institution :
Sandia Nat. Labs., Albuquerque, NM, USA
fDate :
7/1/2011 12:00:00 AM
Abstract :
We present an approach to create ultrathin (<;20 μm) and highly flexible crystalline silicon sheets on inexpensive substrates. We have demonstrated silicon sheets capable of bending at a radius of curvature as small as 2 mm without damaging the silicon structure. Using microsystem tools, we created a suspended submillimeter honeycomb-segmented silicon structure anchored to the wafer only by small tethers. This structure is created in a standard thickness wafer enabling compatibility with common processing tools. The procedure enables all the high-temperature steps necessary to create a solar cell to be completed while the cells are on the wafer. In the transfer process, the cells attach to an adhesive flexible substrate which, when pulled away from the wafer, breaks the tethers and releases the honeycomb structure. We have previously demonstrated that submillimeter and ultrathin silicon segments can be converted into highly efficient solar cells, achieving efficiencies up to 14.9% at a thickness of 14 μm. With this technology, achieving high efficiency (>;15%) and highly flexible photovoltaic (PV) modules should be possible.
Keywords :
bending; elemental semiconductors; honeycomb structures; micromechanical devices; silicon; solar cells; Si; adhesive flexible substrate; bending; curvature radius; high efficiency photovoltaic module; high-temperature steps; highly efficient solar cells; highly flexible crystalline silicon sheet; highly flexible photovoltaic module; honeycomb structure; microsystem tools; microsystems-enabled photovoltaics; processing tools; size 2 mm; submillimeter silicon segment; suspended submillimeter honeycomb-segmented silicon structure; transfer process; ultrathin crystalline silicon sheet; ultrathin flexible crystalline silicon; ultrathin silicon segment; Photovoltaic cells; Photovoltaic systems; Silicon; Stress; Substrates; Crystalline silicon; microsystems-enabled photovoltaics; photovoltaic modules;
Journal_Title :
Photovoltaics, IEEE Journal of
DOI :
10.1109/JPHOTOV.2011.2162973