Chiang Mai Journal of Science

This work reports the synthesis of exfoliated graphite (EG) via electrochemical exfoliation and the fabrication of EG/TiO₂ composite films by spin coating for enhanced UV photodetection. EG was produced in 0.1 M H₂SO₄ under 10 V and fractionated by centrifugation at 2,000, 5,000, and 9,000 rpm in dimethylformamide. TiO₂ films were deposited on glass and annealed at 500 °C to improve crystallinity and adhesion. Structural and spectroscopic analyses confirmed exfoliation and composite formation. XRD showed graphite peaks at 2θ = 26.19° along with graphene-related phases, while annealed TiO₂ displayed anatase peaks. Raman spectra exhibited EG D- and G-bands (1,339 and 1,589 cm⁻¹) together with TiO₂ features. SEM revealed layered EG sheets whose morphology varied with centrifugation speed, and EG/TiO₂ films showed TiO₂ nanoparticles forming sponge-like agglomerates partially coated by EG. Photocurrent tests under 190 μW cm⁻² UV irradiation at ±20 V demonstrated that EG/TiO₂ devices with EG centrifuged at 9,000 rpm outperformed both pristine TiO₂ and lower-speed EG composites. Moreover, stability tests over six weeks showed consistent photocurrent responses with ~9% relative standard deviation, confirming reliable device performance.