Ultrathin Flexible Crystalline Silicon: Microsystems-Enabled Photovoltaics

Jose L. Cruz-Campa, Gregory N. Nielson, Paul J. Resnick, Carlos A. Sanchez, Peggy J. Clews, Murat Okandan, Tom Friedmann, Vipin P. Gupta
2011 IEEE Journal of Photovoltaics  
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 radii as small as 2 mm without damaging the silicon structure. Using Microsystem tools, we created a suspended sub-millimeter 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 tools. The
more » ... tools. The procedure allows all the high temperature steps necessary to create a solar cell to be done 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 sub mm and ultrathin silicon segments can be converted into highly efficient solar cells, achieving efficiencies up to 14.9% in thicknesses of 14 µm. With this technology, achieving high-efficiency (>15%) and highly-flexible PV modules should be possible.
doi:10.1109/jphotov.2011.2162973 fatcat:umjsvwa44bcuthwijjat3kjyta