Bassel Abdel-Samad, Université de Moncton, Moncton, New Brunswick, Canada
This research explores the fabrication and characterization of molybdenum trioxide (MoO₃) thin films for solar applications, utilizing a sustainable sol-gel method combined with spin-coating at 4000 RPM. The study systematically investigates the impact of solvent type, specifically acetone, water, and toluene, and concentration (5% to 20%) on the material's properties. Optical characterization via spectrophotometry revealed that films prepared with acetone and toluene maintain high transparency, with transmission levels reaching approximately 90%, whereas water-based films showed a slight decrease in transparency to about 80% at higher concentrations. Electrical analysis indicated that the choice of solvent significantly affects conductivity and resistivity, with acetone typically promoting smoother, more homogeneous surfaces that enhance reflective stability. A critical component of the research involved determining the energy band gap using the Tauc-plot method, which found values ranging from 3.4 eV to 3.6 eV. Thermal annealing tests performed up to 500°C demonstrated that these films undergo significant structural stabilization, with the band gap values aligning closely with theoretical expectations (3.2–3.45 eV) after treatment. Ultimately, the study concludes that while all three solvents are viable, toluene and acetone favor the formation of high-quality, transparent films, making them superior candidates for optimizing the efficiency of next-generation photovoltaic and optoelectronic devices.