PEDOT:PSS-free organic photovoltaic cells using tungsten oxides as buffer layer on anodes

Tungsten oxide (WO3) was used as an anode buffer layer in conventional poly(3-hexylthiophene):[6,6]-phenyl C61 butyric acid methyl ester (P3HT:PCBM-60) bulk hetero junction (BHJ) cells. Such a buffer layers acts as a hole-extraction layer and reduce series resistance, which leads to better performance of organic electronic devices. Organic photovoltaic (OPV) cells consisting of ITO/WO3/P3HT:PCBM/Al were fabricated. Photovoltaic devices with a short-circuit current density of 7.77 mA/cm(2), an open-circuit voltage of 6.1 V, and a power conversion efficiency of 2.61% were achieved. This study revealed that WO3 based cells have significant shunt resistance which contributes to a high fill factor and open-circuit voltage. This demonstrates potential for using WO3 in poly(stylenesulfonate) doped poly(3,4-ethylenedioxythiophene):(PEDOT:PSS)-free systems.