Experimental and First-Principles Investigations of Lattice Strain Effect on Electronic and Optical Properties of Biotemplated BiFeO3 Nanoparticles

Abstract

High purity BiFeO3 nanoparticles were successfully prepared by employing a green and facile biotemplated method which utilized polysaccharides of κ-carrageenan. The particles’ size of BiFeO3 nanoparticles exhibited significant correlations between structural, electronic, and optical properties that have been investigated by both experimental and first-principles methods. First-principles calculations were performed by means of density functional theory (DFT). Structural analysis revealed that the all-prepared BiFeO3 was crystallized in a rhombohedrally distorted structure, along with an average crystallite size of 14.59 nm. The refined lattice parameter and crystal volume obtained by means of the Rietveld refinement method indicated a good agreement with the calculated data; the lattice strain is found in BiFeO3 nanoparticles. From the linear fit using the Kulbeka–Munk method, a small direct and indirect optical energy gap was found to be 2.17 and 1.84 eV, respectively. In addition, first-principles studi...