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-C₆₀ 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.