Synthesis and investigation of properties of bismuth sulfide nanoparticles by solvothermal method

Abstract In this research, bismuth sulfide (Bi₂S₃) nanoparticles were synthesized using the solvothermal method, and their structural, chemical, and optical properties were investigated. Characterization of the nanoparticles was performed using FT-IR, XRD, SEM, EDX, UV-Vis, and PL techniques. FT-IR results confirmed the presence of functional groups related to the bismuth sulfide structure, with characteristic Bi-S stretching vibrations observed at 450–600 cm⁻¹. The X-ray diffraction (XRD) pattern revealed the orthorhombic crystal structure of the nanoparticles, and the crystallite size was calculated to be approximately 38 nm using the Debye-Scherrer equation. SEM images showed a uniform morphology and nanoscale structure of the particles with needle-like structures in the range of 40–90 nm, while the EDX spectrum confirmed the presence of pure bismuth and sulfur elements with weight percentages of 78.8% and 21.2%, respectively. The UV-Vis spectrum calculated the energy gap of the nanoparticles to be 2.45 eV. Additionally, the PL spectrum identified electronic transitions and optical properties of the nanoparticles with a main emission peak at around 500 nm. Due to their unique optical and electronic properties, these nanoparticles have high potential for use in solar cells, sensors, and optoelectronic devices.