Sol-gel synthesis of topological insulator bismuth selenide nanoparticles by using different solvents

This paper reports about the Sol-Gel synthesis of Bismuth Selenide (Bi₂Se₃) nanoparticles by using different solvents (DMF, Ethanol and (DMF+Ethanol)) for their potential in topological insulators. Various characterization techniques: X-ray diffraction (XRD), Fourier Transform Infrared spectroscopy (FTIR), photoluminescence (PL), and scanning electron microscope (SEM) were used to characterize the nano-powder. To get valuable information about dielectric behavior, AC impedance and conductivity were studied. The XRD measurements of Bismuth Selenide proved the crystalline form and orthorhombic crystal structure. The grain size (G) of Bismuth Selenide prepared in different solvents e.g., DMF, Ethanol, DMF+ Ethanol were calculated at 68 nm, 78 nm, and 84 nm respectively. FTIR study showed that the wavenumber corresponding to 660-800cm^-1 represents the vibrational bands of Bismuth Selenide (Bi₂Se₃). Photoluminescence analysis revealed that the maximum absorption was at 801 nm and the bandgap was approximately 1.7eV for all the solvents. The surface morphology of the synthesized Bismuth Selenide (Bi₂Se₃) was studied with the help of a scanning electron microscope (SEM). The dielectric study showed the frequency effect on dielectric constant (έ), dielectric loss (Ɛ"), tangent loss (tanδ), impedance (Z), and AC conductivity.