Transparent conductive ZnInSnO-Ag-ZnInSnO multilayer films for polymer dispersed liquid-crystal based smart windows

Multilayer transparent films with electrical resistances lower than those in conventionally used transparent conductive electrodes were prepared at room temperature on glass substrates in an RF/DC magnetron sputtering system. The multilayer structure of the films consisted of three layers, ZnInSnO (ZITO)-Ag-ZITO. The optical and electrical properties of the multilayer structures were investigated with respect to the thickness of each ZITO-Ag-ZITO layer. Transparent conductive films with a sheet resistance of 9.4 Omega/square and an average transmittance of 92% at 550 nm were obtained at the following thicknesses of the glass substrate: ZITO (100 nm)-Ag (8 nm)-ZITO (42 nm). The surface roughness (R-RMS) of the obtained ZITO-Ag-ZITO multilayer films was below 0.8 nm. Overall, the properties of the ZITO-Ag-ZITO multilayer films were comparable or superior to those of other multilayers such as InSnO (ITO)-Ag-ITO and InZnO (IZO)-Ag-IZO. The deposited ZITO single layer and ZITO-Ag-ZITO multilayer films were used in the fabrication of polymer-dispersed liquid-crystal (PDLC)-based smart windows. The ZITO-Ag-ZITO multilayer-based smart windows exhibited a lower operating voltage (16V) and a higher cutoff rate of infrared light than ITO or ZITO-based smart windows 20-26 V. However, they showed a lower PDLC-ON transmittance than ITO-based smart windows. (C) 2014 The Japan Society of Applied Physics