Structural, Optical, Electrical and Photocatalytic Investigation of n-Type Zn²⁺-Doped α-Bi₂O₃ Nanoparticles for Optoelectronics Applications

Abstract

Herein, n-type pure and Zn 2+ -doped monoclinic bismuth oxide nanoparticles were synthesized by the citrate sol−gel method. X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), photoluminescence (PL) analysis, ultraviolet−visible (UV−vis) spectroscopy, and Hall effect measurements were used to study the effect of Zn 2+ on the structural, optical, and electrical properties of nanoparticles. XRD revealed the monoclinic stable phase (α-Bi 2 O 3 ) of all synthesized samples and the crystallite size of nanoparticles increased with increasing concentration of dopant. Optical analysis illustrated the red shift of absorption edge and blue shift of band gap with increasing concentration of dopant. Hall Effect measurements showed improved values (2.79 × 10 −5 S cm −1 and 6.89 cm 2 /V•s) of conductivity and mobility, respectively, for Zn 2+doped α-Bi 2 O 3 nanoparticles. The tuned optical band gap and improved electrical properties make Zn 2+ -doped α-Bi 2 O 3 nanostructures promising candidates for optoelectronic devices. The degradation of methylene blue (MB, organic dye) in pure and zinc-doped α-Bi 2 O 3 was investigated under solar irradiation. The optimum doping level of zinc (4.5% Zn 2+ -doped α-Bi 2 O 3 ) reveals the attractive photocatalytic activity of α-Bi 2 O 3 nanostructures due to electron trapping and detrapping for solar cells.