Antireflective Paraboloidal Microlens film for Boosting Power Conversion Efficiency of Solar Cells.

Microlens array is desired for improving visibility in optical devices or the enhancement of power conversion efficiency of the photovoltaic device. Its surface morphology (height-width ratio and packed density) is vital to photon management in solar cells. Here, we report a close-packed paraboloidal microlens arrays (PMLAs) with a large bump height using direct-write UV laser photolithography coupled with soft imprint lithography technique. Optical property investigations show that the PMLA structure can significantly reduce the device front-side reflectance. The systematic solar cell device electrical characterizations clearly and consistently show that the PMLA film can considerably improve the photoelectrical conversion efficiency. In addition, the PMLA film have superhydrophobic characteristic with a large water contact angle and can enhance the self-cleaning capability of solar cells.