The present paper reports the multifunctional properties of lead‐free BiFeO3–La (BFO–La) thin films. The structural, microstructural, and optical properties have been investigated as a function of the lanthanum doping concentration. The structural properties at room temperature showed the formation of the perovskite structure, thus suggesting the high quality of the obtained thin film compositions. Raman spectroscopy analysis revealed a slight variation in both the peak position and absolute intensity for the Raman active modes, as lanthanum content increases in BiFeO3–La. Crystallized thin films with well‐defined grains as well as crack‐free surfaces have been obtained, for all the studied compositions, as inferred from atomic force microscopy images. The optical properties have been measured, and the values for the direct bandgap was significantly lower than those reported for other BFO‐based systems, being the lowest ∼1.87 eV for the Bi0.90La0.10FeO3 composition. Results revealed a noteworthy effect of the defect concentrations induced by the lanthanum doping on the long‐range crystallinity and directly affecting the polarizability of the A–O bond as well as the Fe–O and Fe–O–Fe bond lengths in the perovskite structure. The enhanced optical absorption properties registered for the Bi1–xLaxFeO3 (x = 0–20) compositions make these perovskite multiferroic thin films as a potential candidate material for the high‐performance photovoltaic device applications.

Lanthanum modified BiFeO3 thin films were prepared via the sol-gel method and deposited through the dip-coating technique on ITO coated substrates. The structural properties were investigated at room temperature from X-ray diffraction as well as Raman spectroscopy. Results confirm the formation of the perovskite structure without secondary phases, thus corroborating the high-quality of the obtained thin films. Well-defined and nanometric scale grains have been obtained from atomic force microscopy, revealing indeed crack-free surfaces. From the technological point of view, this result is very important since residual stresses promoted by surface cracks led to additional conduction behavior, which could affect the real electric response of the sample to be used in electronic devices.

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