Colored Ribbons Achieve +0.28%$_{\bf abs.}$ Efficiency Gain

Flat metallic ribbons connect the solar cells in conventional crystalline silicon modules. Acting like a mirror, they reflect incoming radiation out of the module. The area covered by the ribbons (around 3.5%) is mainly lost for photovoltaic conversion. We present colored cell connectors which scatter incident irradiation. Due to subsequent total internal reflection at the glass/air interface, the photons get a second chance to reach the active module area. White ribbons increase the module efficiency from η = 14.7% by Δη = 0.28%_abs. to nearly 15%. Applying ultraviolet (UV) fluorescent dye on top of the white paint increases the quantum efficiency of lower wavelengths even further. Reduced optical losses allow a novel optimization of optical versus electrical losses. A simulation determines the optimum amount of white painted ribbons, balancing of the lower optical shadowing, and the higher series resistance of the module. The simulation predicts an efficiency gain Δη = 0.33%_abs..