Changes in optical properties and structural phases grown upon forming ZnMn2O4/ZnFe2O4 heterostructure nanocomposite

Highlights: • Dissolving of some ions of one phase into the matrix of other phases. • XPS analysis demonstrated that the presence of Zn²⁺, Mn³⁺ and Fe³⁺ ions. • All nanocomposite samples have a normal dispersion except ZFO sample. • The 0.2ZMO/0.8ZFO nanocomposite sample exhibited a good nonlinear optical behavior. • The nanocomposite samples can be used in the photocatalytic application. The heterostructure nanocomposites (1-x)ZnMn₂O₄/xZnFe₂O₄ (x = 0, 0.2, 0.5, 0.8, 1) are formed using the co-precipitation technique. X-ray diffraction and Fourier-transform infrared spectroscopy data disclosed the dissolving of some ions of one phase into the matrix of the other phase. Composite samples with x = 0.5 and 0.8 have an extra ZnO phase and its percentage increased with increased ZnFe₂O₄ (ZFO) amount in the matrix. The elements constituting the samples and the cations valence state are determined by X-ray photoelectron spectroscopy technique (XPS). The effect of composition parameter (x) on the absorbance spectra, extinction coefficient, refractive index, dielectric constant (real and imaginary), dielectric loss and optical conductivity is investigated by UV diffused reflectance technique. The optical band gap (E_g) of (1-x)ZMO/xZFO (x = 0.2, 0.5) nanocomposite samples was decreased to 2.4, 2.38 while the E_g of nanocomposite sample with x = 0.8 was increased to 2.54 eV. All nanocomposite samples have a normal dispersion similar to ZnMn₂O₄ (ZMO) sample. ZFO sample exhibited both normal and anomalous dispersion depended on the wavelength range. The 0.2ZMO/0.8ZFO nanocomposite sample exhibited a good nonlinear optical behavior at low frequency. The photoluminescence (PL) intensities of nanocomposite samples are quenched as ZMO alloyed with ZFO. Different emitted colors are observed as the ratio of ZMO and ZFO altered in the matrix.