Enhanced efficiency of organic solar cells by using ZnO as an electron-transport layer

This paper reports the use of ZnO, processed by sol-gel, as an efficient electron-transport layer for inverted organic photovoltaic cells. The device with incorporated ZnO interlayer, annealed at 100 degrees C, between transparent electrode and blend film plays an effective role in enhancing photovoltaic properties: the short-circuit current density (J(sc)) doubles while open-circuit voltage (V-oc) and fill factor increase by 0.12 V and 10 %, respectively. Power conversion efficiency (PCE) of solar cell increases, approximately, three times. The improvement in the PCE is attributed to the presence of ZnO which, being an electron-facilitating layer, provides an energy step for charge collection at electrodes.