Effect of ZnO processing on the photovoltage of ZnO/poly(3-hexylthiophene) solar cells

Proper contact and band alignment across the heterojunction interface is critical to the performance of hybrid pi-conjugated polymer-nanostructured metal oxide photovoltaic devices. We investigated the effect of ZnO surface processing on ZnO/poly(3-hexylthiolphene) device performance. Devices in which the ZnCl films/nanorods were heated at 150 degrees C in air exhibited an open circuit voltage similar to 200 mV higher than devices with ZnO treated by UV/ozone. We conclude that the differences observed in the two types of devices predominantly arise from changes in interfacial dipoles, and intermediate materials processing can be critical to solar cell performance.