We report the fabrication and operation of organic photovoltaic cells with lateral junctions and separated carrier-generating and carrier-transporting layers. Significant photocurrent increase was observed by inserting carrier generating layer having strong visible absorption. For the lateral tandem cells, an increase in the number of unit cells increased the photocurrent while keeping the photovoltage constant. It is easier to increase the number of unit cells in lateral tandem cells compared to conventional vertical tandem cells because the adjustment of photocurrent density flowing in each unit cell is no longer necessary.

In this study, the photovoltaic behavior of centimeter-long lateral organic junctions, reaching 1.8 cm, is reported. The organic junctions are formed using organic semiconductor films with high mobilities of holes and electrons. The lateral diffusion lengths of photogenerated electrons and holes are 4.7 and 5.5 mm, respectively. The photovoltaic behavior in the centimeter-long lateral junctions is controlled by the trap-assisted recombination between the electrons and holes.