High ferroelectric performance of Bi0.9La0.1FeO3 thick film by optimizing preparation precursor solution

The high-concentration precursor solution of Bi0.9La0.1FeO3 (BLFO) was fabricated and stored under the different temperatures (40, 20, 0 °C). After 10 days, the solution at the temperature of 40 °C generated both bismuth acetate precipitation and nitrogen dioxide gas and at the temperature of 20 °C generated nitrogen dioxide gas, while the solution still maintains stability and transparency at the temperature of 0 °C. These results show that low temperature is an important way to improve the stability of high-concentration precursor solution in sol–gel method. Furthermore, the stability precursor solution is adopted to prepare BLFO thick film on indium tin oxide/glass substrate by spin coating combined with sequential layer annealing. The film exhibits a perovskite structure without impurity phase; especially, a comparatively high remanent polarization (P r) of 42.85 μC/cm2 can be obtained, which may be related to lanthanum doping, preferred (110) orientation and relatively compact microstructure. XRD patterns and cross-sectional structure of Bi0.9La0.1FeO3 thick film, polarization–electric field (P–E) loops at various voltages.