Photomask Effect in Organic Solar Cells With ZnO Cathode Buffer Layer

In this letter, we report on the performance of conventional bulk heterojunction organic solar cell (OSC) incorporating a solution-processed zinc oxide (ZnO) spin coated on the photoactive layer regioregular poly(3-hexylthiophene) : indene-C-60 bis adduct. We show a significant improvement in short-circuit current density (J(sc)) upon an introduction of ZnO, and this is further evidenced by the reduction of J(sc) leading to a lower PCE in the device without the presence of ZnO. Furthermore, we also examined the photomask on the performance of ZnO-based device yielding a decrease in both J(sc) and open-circuit voltage V-oc (of about 13.42% and 0.73%, respectively) but an increase in filling factor. Results demonstrate that ZnO plays an important role in the improvement of OSCs' performance.