Thick polymer blend organic solar cells fabricated by slow drying

Organic solar cells (OSCs) were generally fabricated by two types of deposition method, namely, dry and wet. Many OSCs use very thin films that cannot fully absorb light. Thick film deposition for OSCs has numerous benefits, such as highly efficient harnessing of solar light and low leakage. Thick film fabrication for polymer blend organic solar cells by the wet deposition method was investigated. OSCs were fabricated by spin coating and slow drying using P3HT and bis[60]PCBM in a solvent, respectively. Two-dimensional (2D)-mapping images of the photocurrent of the cells were measured by a laser-beam-induced current method. A low-current density area was not found in all the cells. As a result, we succeeded in fabricating OSCs with a power conversion efficiency of more than 4% by slow drying.