Efficiency enhancement of top-incident organic photovoltaics using multiple reflection design for exhausting incident photons

A significant efficiency enhancement of the small-molecule top-incident organic photovoltaic (TIOPV) module is demonstrated by utilizing a light harvesting design with multiple reflections to effectively exhaust the incident photons. In this design, the reflection from one OPV is the incident light for another OPV in this light harvesting design. Adjusting the thickness of active layers sandwiched in between reflective Ag anode and semitransparent Ag cathode, the internal optical filed distribution and external reflection spectrum have been rearranged for a single TIOPV. The external reflection photon energy could be partially absorbed by the next TIOPV device to generate the conversion photocurrent. The original incident photon energy could be exhausted after a sequence of reflections, converting to photocurrent.