Effect of Gold-Modified Titanium Dioxide Thin Films on Electrical Resistance, Optical Transmittance, and Wetting Properties
DOI:
https://doi.org/10.48048/tis.2026.12946Keywords:
Titanium dioxide, Gold, Thin films, Sparking process, Sputtering deposition, Four-point probe, Sheet resistance, Hydrophilicity stabilityAbstract
Titanium dioxide (TiO2) thin films were synthesized via the sparking process at different durations and modified with gold (Au) by DC magnetron sputtering to study the effects of microstructure, plasmonic interactions, and interfacial charge transport. Pristine TiO2 films showed a transition from fine, uniform nanograins (1 h) to agglomerated structures (3 - 5 h), reducing transparency and increasing defect density, while thicker films exhibited improved electrical continuity. The 1 h TiO2 film offered the optimal balance of high transparency (~90%), uniform morphology, and long-term hydrophilicity. Au deposition significantly influenced film properties: Increasing sputtering current (10 - 50 mA) enhanced Au loading, transforming discontinuous nanoparticles into a percolated network at 30 mA, and causing agglomeration at 50 mA. This morphology controlled plasmonic absorption, sub-band-gap optical behavior, and conductivity. Au modification reduced sheet resistance from 37 MΩ/sq to 5.8 Ω/sq (30 mA) and enabled visible-light absorption via localized surface plasmon resonance and metal-induced gap states. Au-coated films maintained water contact angles <30° over 60 days, attributed to stabilized surface hydroxylation and suppression of hydrocarbon adsorption. Sputtering at 30 mA produced the optimal Au-TiO2 architecture, balancing transparency, conductivity, plasmonic activity, and durable wettability, offering a promising approach for low-cost transparent coatings, optoelectronic devices, and self-cleaning surfaces.
HIGHLIGHTS
- TiO₂ thin films were successfully fabricated using a sparking process and modified with Au by sputtering.
- Au deposition significantly reduced sheet resistance from MΩ to Ω range due to improved electrical percolation.
- Plasmonic interaction from Au nanoparticles enhanced visible-light absorption and optical behavior.
- The optimized Au-TiO₂ thin films maintained stable hydrophilicity (<30° contact angle) for 60 days.
- The developed Au-TiO₂ thin films show strong potential for transparent coatings, optoelectronics, and self-cleaning surfaces.
GRAPHICAL ABSTRACT
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