Chiang Mai Journal of Science

     Optimal precursor volume in aerosol-assisted chemical vapor deposition (AACVD) is crucial for film deposition as it determines the overall performance of devices. This study investigates the influence of precursor volume on tungsten oxide (WO₃) film properties for photoelectrochemical (PEC) water splitting. Tungsten oxide films were deposited at 450 °C using 10, 20, and 30 ml precursor volumes via AACVD. The fabricated photoelectrodes were analyzed for structural, morphological, optical, and PEC performance. The UV-Vis absorption showed that WO3 film prepared using 20 ml precursor volume has the lowest energy bandgap of 2.72 eV. The sample also exhibited the highest photocurrent density of 0.19 mA cm-² at 1.23 V (vs. Ag/AgCl). This result matched the impedance analysis, which demonstrated the lowest charge transfer resistance at electrode-electrolyte interface. This work highlights precursor volume as a critical parameter in AACVD for tailoring WO₃ morphology and PEC activity, providing insights for scalable photoelectrode design.