Abrasion-resistant, transparent, conductive In2O3@SiO2 films

Abstract

External smart wearable films requires that films have good transparency, electrical conductivity, wear resistance and corrosion resistance, but the research on some issues have not been discussed anywhere. The composite In2O3@SiO2 functional films intended for smart wearable devices were synthesised via closed-field unbalanced magnetron sputtering from a powder target. This study investigated the impact of the Si:In atomic ratio in the target on the films' transparency, conductivity, resistance to sweat corrosion, and wear resistance, while elucidating the underpinning mechanisms. Results revealed that the film roughness declined from 4.41 to 1.5 nm with increasing Si:In ratio, and the preferred orientations observed in the pure In2O3 film were lost upon the incorporation of SiO2 particles. The films maintained a visible-region transmittance of 82–85%. However, the band gaps and sheet resistances increased from 3.78 to 4.3 eV and 52–2740 Ω·sq−1, respectively. The In2O3@SiO2 film with 10 at. % SiO2 demonstrated relative structural integrity, and minimal changes in optical and electric properties after acid treatment. Films with 15 at. % SiO2, both with and without exposure exhibited pitting and peeling, with changes in transmittance and sheet resistance of 14.44% and 13.08%, respectively. The alkali-treated films displayed minimal changes. The pure In2O3 film failed after 30 h of vibration. After 48 h of vibratory wear, the In2O3@SiO2 films' transmittance decreased to approximately 72%, and sheet resistances increased to 2.5 KΩ for 10 at. % SiO2 and 23 KΩ for 15 at. % SiO2. The evenly dispersed SiO2 nanodots of the In2O3@SiO2 film with 10 at. % SiO2 showed superior overall properties, including transparency, conductivity, sweat corrosion resistance, and wear resistance, attributed to the ‘maze effect’ obstructing corrosion pathways and the ‘mosaic pattern’ enhancing the abrasive properties.