Optical absorption enhancement of P3HT:PCBM films through nanocavities using polystyrene as a template

•Nanocavities in P3HT:PCBM films were obtained using polystyrene as a template.•Nanocavities improve optical absorption due to the scattering of light.•The absorption enhancement provides an advantage due to the increase in the amount of energy that can be harvest.•The methodology proposed may have promising applications in active materials for organic solar cells. A relatively simple and inexpensive method to enhance the optical absorption of P3HT:PCBM films is hereby presented. By evaporating different concentrations of polystyrene in the mixtures, nanocavities were obtained. An increase in the optical light path due to the internal reflection between the cavities and the P3HT:PCBM media, enhances the optical absorption. Theoretical density photocurrents were calculated for these films, and considerable increases were obtained compared to films without cavities. The methodology proposed may have promising applications in active materials for organic solar cells.