Detailed investigation of the optical properties of the (C₈H₁₁BrN)₃BiCl₆ compound by UV–visible measurements

Abstract

The UV–visible studies of the hybrid tris(4-bromo-N,N-dimethylanilinium) hexachlorobismuthate (III) compound [(C₈H₁₁BrN)₃BiCl₆], prepared by slow evaporation at room temperature, were investigated in detail from 200–2400 nm. The absorption peaks show the presence of a peak in the UV–C region around $\lambda_{\rm des} = 254$ nm which has the property of disinfecting water. The optical bandgap E_g, determined by both absorbance and reflectance measurements, was estimated to be (3.390 ± 0.009) and (3.354 ± 0.009) eV, respectively. In addition, these measurements approve the direct behaviour of the allowed optical transitions. The low Eurbach energy (128 meV) confirms the high quality of the prepared sample. The dependence on the incident wavelength of the optical constants such as the extinction coefficient k and the refractive index n was discussed. The dispersion parameters E₀ and E_d of this compound were calculated on the basis of the Wemple–Didomenico model. Furthermore, the dielectric studies show that the dissipation factor tan $\delta$ has very low value. All the results demonstrate that this compound may be proposed as a good candidate for optical and optoelectronic applications.