Photovoltaic effect in Sr-doped BiFeO3 thin films

Abstract

Abstract We present the structural and photovoltaic properties of Sr-doped polycrystalline BiFeO3 thin films prepared by sol-gel method. The result shows that all the BiFeO3 thin films doped with 0\u2009∼\u200920 at.% Sr are rhombohedral distortion perovskite structure and the lattice constant decreases with increasing Sr amount. The addition of Sr can effectively inhibit the grain growth and enhance the uniformity of BFO films, besides, the band gap can be tuned availably as well. As Sr content increases, both the short circuit photocurrent density and the open circuit photovoltage begins to increase and then decrease, the maximum values achieved when 15 at.% Sr-doped. The power conversion efficiency accordingly increases first and then drops with Sr content increases, reaching 0.011% when the Sr-doped content is 15%, which results from the decreased band gap and oxygen vacancies. Highlights All the BiFeO3 thin films are rhombohedral distortion perovskite structure. Addition of Sr decreases the band gap of BFO thin films. The power conversion efficiency increases as Sr content increases. The maximal power conversion efficiency is 0.011%