Surface Plasmon and Scattering-Enhanced Low-Bandgap Polymer Solar Cell by a Metal Grating Back Electrode

The active layer of a low bandgap polymer solar cell has been patterned by a simple imprinting technique, and thin metal oxide/metal layers have been coated on the active layer to form a metal grating back electrode. By finely controlling the distance between the grating and active layer, about 10% short current enhancement (Jsc) is seen, without any obvious degradation to the open circuit voltage or fill factor. The power conversion efficiency increases from 7.20 to 7.73%, which is due to absorption enhancement from waveguide modes, Wood's anomaly, and plasmonic effects.