Improved ferroelectric and photovoltaic properties of BiMnO3 modified lead-free K0.5Na0.5NbO3 solid-solution films

Abstract

Lead-free K0.5Na0.5NbO3/BiMnO3 solid-solution films were deposited on Pt/Ti/SiO2/Si substrates by solution-gelation methods. The effects of the BiMnO3 addition on the electric, bandgap, and photovoltaic properties were investigated systematically. It is shown that, compared with traditional K0.5Na0.5NbO3 films, BiMnO3 modification obviously enhances the ferroelectric properties due to the depression of the leakage current and the improvement of the domain. More importantly, the ferroelectric photovoltaic effect is observed with a large short-circuit current and open-circuit voltage in the lead-free solution films, which is ascribed to the excellent ferroelectric properties and photovoltaic response in the visible region derived from the narrow bandgap modified by BiMnO3. The present work provides strong candidates to be applied in environmentally friendly lead-free ferroelectric photovoltaic solar cell and information storage devices.