Optimizing physical properties of BiFe1-xMnxO3 perovskite thin films via a low-temperature sol-gel method

Multiferroic materials have recently attracted great attention for possible use in photovoltaic and photocatalytic devices. In this study, pure-phase BiFe1-xMnxO3 (x = 0.0, 0.1, 0.2, 0.3, 0.4, 0.5) thin films were deposited on glass substrates via low-temperature sol-gel assisted spin coating procedure. We found that the thin films undergo a rhombohedral to cubic structural transition. From FESEM images, it was observed that different amount of Mn affects the surface morphology and grain size of the studied samples. For all samples, the absorption coefficient was in the range of 105 cm-1, and the refractive index and extinction coefficient of samples were about 1.15-1.50 and 0.2-0.9, respectively. BiFe0.8Mn0.2O3 thin film has the lowest bandgap energy due to the highest absorption coefficient at the wavelengths of 400-1100 nm denoted by its lowest transmittance. Structural and magnetic results show the substitution of low-spin smaller Mn ions for high-spin larger Fe ions. The best photocatalytic activity was observed for BiFe0.8Mn0.2O3 thin film with a removal efficiency of 78.83% in the photodegradation of methylene blue.

Automated summary

In this study, pure-phase BiFe1-xMnxO3 (x = 0.0, 0.1, 0.2, 0.3, 0.4, 0.5) thin films were deposited using a low-temperature sol-gel assisted spin coating procedure. It was found that the films underwent a structural transition and the surface morphology and grain size were affected by the amount of Mn. The BiFe0.8Mn0.2O3 thin film showed the lowest bandgap energy and exhibited the best photocatalytic activity.