Reversed organic–inorganic hybrid tandem solar cells for improved interfacial series resistances and balanced photocurrents

We report a promising approach to fabricate organic–inorganic hybrid tandem photovoltaic devices with a reversed configuration. High bandgap hydrogenated amorphous silicon (a-Si:H) was deposited with plasma-enhanced chemical vapor deposition onto a solution-processed low bandgap organic photovoltaic (OPV) subcell. Two important factors for efficient tandem solar cells, interfacial series resistance (RS,int) and balanced photocurrents, were investigated. The intimate interfacial contact eliminated the RS,int, and sufficient transmittance of the OPV front subcell led to the well-balanced photocurrents. As a result, this reversed hybrid tandem device showed an enhanced efficiency of 3.3% and an open-circuit voltage of 1.51 V.