Semitransparent low-bandgap polymer solar cells with high transmisision in green-wavelength range

Optical modeling based on transfer matrix method (TMM) is employed to investigate the performance of the semitransparent low-bandgap polymer solar cells (PSCs), which are constructed by sandwiching the polymer active layer between an indium tin oxide (ITO) electrode and a thin Ag electrode. It is revealed that the efficiency of the device is more than 2.5% with high transmission across the visible spectrum. In addition, by capping a 40nm-thick MoO₃ layer on the thin Ag electrode, the transmission at the green-wavelength range (500-570nm) can be increased to over 70%. Furthermore, comparison between the devices with low-bandgap polymer and high-bandgap polymer demonstrates semitransparent PSCs with transmission window at the red and green part of the spectrum can be achieved by selecting suitable active layer material.