Semitransparent organic photovoltaics (OPVs) have drawn significant attention for their promising potential in the field of building integrated photovoltaics such as energy-generating greenhouses. However, the conflict between the need to attain satisfying average visible transmittances for greenhouse applications and the need to maintain high power conversion efficiencies is limiting the commercialization of semitransparent OPVs. A major manifestation of this issue is the undermining of charge carrier extraction efficiency when opaque, visible-light-absorbing electrodes are substituted with semitransparent ones. Here, we incorporated a dual-function p-type compatible interlayer to modify the interface of the hole-transporting layer and the ultrathin electrode of the semitransparent devices. We find that the p-type interlayer not only enhances the charge carrier extraction of the electrode but also increases the light transmittance in the wavelength range of 400-450 nm, which covers most of the photosynthetic absorption spectrum. The modified semitransparent devices reach a power conversion efficiency of 13.7% and an average visible transmittance of 22.2%.
Keywords: charge carrier extraction; contacts; optical distribution; organic photovoltaics; semitransparent.