Photodeposited Ag-Wires on TiO2 Films

Highly conductingfilms of Ag are photodeposited onto commercial self-cleaning glass (Pilkington, Activ™), aswell as in-house prepared sol-gel TiO2films, using an aqueous solution of AgNO3containing a sacrificial electrondonor, glycerol. Wire tracks are created by irradiating the photocatalytic surface through a stencil, promotingAg-deposition only on the exposed/irradiated areas. The ability of the Ag-wires to conduct, and so heat up theunderlying glass, is investigated initially for demisting purposes. The photodeposited Ag-wires on Activ™glassare found to have a resistance of ca. 150Ωafter 2 h irradiation (I = 4 mW cm−2, 352 nm BLB), whereas the Ag-wires on sol-gelfilm, prepared under the same conditions, are ca. 3 times less resistive (55Ω). Repeat heating-cooling cycles are achieved by applying a voltage, 12 V, across the Ag wires and demonstrate the robustness ofthe Ag-wires on Activ™and sol-gelfilms, which produce a consistent rise in temperature above ambient roomtemperature of 20 °C, and 40 °C, respectively. A Scanning Electron Microscopy (SEM) study of Ag-particle growthon sol-gel TiO2films demonstrates island growth of the Ag-particles, producing Ag‘wires’that are only able toconduct once the Ag‘islands’overlap; typically this is after ca. 9 min of irradiation (I = 4 mW cm−2), withR = 200 kΩand Ag’island’particle size = ca. 100 nm. Upon further irradiation, the particles eventually growsufficiently large that most Ag particles overlap and the resulting Ag wires are highly conducting (R = 55Ωafter2 h).Highly conductingfilms of Ag are photodeposited onto commercial self-cleaning glass (Pilkington, Activ™), aswell as in-house prepared sol-gel TiO2films, using an aqueous solution of AgNO3containing a sacrificial electrondonor, glycerol. Wire tracks are created by irradiating the photocatalytic surface through a stencil, promotingAg-deposition only on the exposed/irradiated areas. The ability of the Ag-wires to conduct, and so heat up theunderlying glass, is investigated initially for demisting purposes. The photodeposited Ag-wires on Activ™glassare found to have a resistance of ca. 150Ωafter 2 h irradiation (I = 4 mW cm−2, 352 nm BLB), whereas the Ag-wires on sol-gelfilm, prepared under the same conditions, are ca. 3 times less resistive (55Ω). Repeat heating-cooling cycles are achieved by applying a voltage, 12 V, across the Ag wires and demonstrate the robustness ofthe Ag-wires on Activ™and sol-gelfilms, which produce a consistent rise in temperature above ambient roomtemperature of 20 °C, and 40 °C, respectively. A Scanning Electron Microscopy (SEM) study of Ag-particle growthon sol-gel TiO2films demonstrates island growth of the Ag-particles, producing Ag‘wires’that are only able toconduct once the Ag‘islands’overlap; typically this is after ca. 9 min of irradiation (I = 4 mW cm−2), withR = 200 kΩand Ag’island’particle size = ca. 100 nm. Upon further irradiation, the particles eventually growsufficiently large that most Ag particles overlap and the resulting Ag wires are highly conducting (R = 55Ωafter2 h).