Large Area Nanostructure Integration for Broad-Spectrum, Omnidirectional Antireflection Improvements on Polymer Packaged, Mechanically Flexible, Epitaxial Lift-Off III-V Solar Cells

We demonstrate the integration of subwavelength moth-eye and A1203 nanoisland structures fabricated on, respectively, polymer packaging sheets and conventional A12O3/TiO2 antireflection coatings on triple junction epitaxial lift-off GaAs solar cells. A scalable, low cost, and high throughput surface patterning process based on nanosphere lithography is presented, and demonstrated experimentally for ELO solar cells and polymer packaging sheets with areas of ~ 20cm2. The mechanically flexible cell structures with integrated optoelectronic nanofeatures show substantial improved photovoltaic performance under large angle illumination. An increase in Isc is seen from 5%-72% at normal and 75-degree incident illumination respectively.