Enhanced photovoltaic effect in K substituted BiFeO3 films

K substituted BiFeO3 films have been fabricated on FTO/glass substrates using the sol-gel method. XRD results show that the films are randomly oriented. UV-Vis absorption results indicate that the films exhibit intense absorbance around 500 nm. The band gaps are 2.52 eV, 2.59 eV, 2.64 eV and 2.62 eV for the 0%, 5%, 10% and 20% K substituted films, respectively. Significantly enhanced photovoltaic effect was observed in the 20% K substituted BiFeO3 film. The short circuit current density and open circuit voltage of the 20% K substituted film are 1.32 μA/cm2 and −0.45 V, respectively.