Photovoltaic module active self-cleaning surface using anisotropic ratchet conveyors fabricated with parylene-C stencil

Abstract

This paper describes an active self-cleaning surface using an anisotropic ratchet conveyor (ARC) to move a water droplet under orthogonal vibrations. Two different ARC systems were designed and fabricated with self-assembled monolayers and hydrophobic Cytop thin films. A novel way to create micro-sized patterns on Cytop was developed without degrading the original Cytop hydrophobicity. Droplet transport speed is 20.5 mm/s at frequency 52 Hz and acceleration 3.3 g (g = 9.8 m/s2). Optical transmission measurements show Cytop can improve optical transmittance by 2.5∼3.5% over the entire visible wavelength range. Solar cell module power output is measured to verify the output power efficiency gain. The self-cleaning function is demonstrated with ARC patterns.