Investigation of nonlinear optical and photocatalytic properties of sol–gel derived KBiFe 2 O 5

KBiFe 2 O 5 polycrystalline powder was synthesized via citrate assisted sol–gel route. Its structural, microstructural, linear, nonlinear optical and photocatalytic properties were investigated. X-ray diffraction analysis revealed its structure to be monoclinic phase at room temperature. Nonlinear optical absorption of this material was investigated using open aperture z-scan technique. A three-photon type absorption mechanism fitted well with the experimental data, and the corresponding nonlinear absorption coefficient was calculated to be 4 × 10 −23 m 3 /W 2 . The band gap of this material as determined by diffuse reflectance spectroscopy was found to be 1.75 eV. This makes it suitable for visible light driven photocatalytic applications. The photocatalytic property of KBiFe 2 O 5 was investigated by degradation of methylene blue under visible light irradiation at different pH. The degradation rate constant was found to be 0.031 min −1 at a pH of 11.