Photovoltaic enhancement based on improvement of ferroelectric property and band gap in Ti-doped bismuth ferrite thin films

• Published in: Journal of alloys and compounds Vol. 617; pp. 240 - 246
• Main Authors: Cai, Wei, Fu, Chunlin, Gao, Rongli, Jiang, Weihai, Deng, Xiaoling, Chen, Gang
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 25.12.2014; Elsevier
• Subjects: Bismuth ferrite; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Dielectrics, piezoelectrics, and ferroelectrics and their properties; Exact sciences and technology; Ferroelectric; Ferroelectricity and antiferroelectricity; Leakage; Optical; Photovoltaic effect; Physics; Titanium doping; Leakage; Ferroelectric; Bismuth ferrite; Photovoltaic effect; Titanium doping; Optical; Photovoltaic effects; Polarization; Bismuth oxide; Doping; Perovskites; Leakage currents; Titanium additions; Thin films; Energy gap; Ferroelectricity; Trigonal lattices; Spin-on coating; Microstructure; Sol-gel process
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2014.08.011

•The leakage current is effectively reduced by adding a certain amount of titanium.•Addition of titanium increases the remnant polarization and decreases the band gap.•The power conversion efficiency increases as titanium content increases. Ti-doped bismuth ferrite thin films were prepared via sol–gel spin-coating method. The effects of titanium on the microstructure, optical, leakage, ferroelectric and photovoltaic characteristics have been investigated systematically. The result shows that bismuth ferrite thin films doped with 0–8at.% Ti are rhombohedral distortion perovskite structure. The addition of titanium inhibits the grain growth and enhances the thickness uniformity and can decrease the band gap of bismuth ferrite thin films. The leakage current of bismuth ferrite thin films is effectively reduced by adding a certain amount of titanium and the leakage mechanism has been investigated. Addition of titanium increases the remnant polarization of the films. As titanium content increases, the short circuit photocurrent density decrease first and then increase, while the open circuit photovoltage increase first and then decrease. The power conversion efficiency of Ti-doped bismuth ferrite thin films increases as titanium content increases, which can be explained as a result of the increased remnant polarization and decreased band gap.