Comparison of Electrochemical Luminescence Characteristics of Titanium Dioxide Films Prepared by Sputtering and Sol--Gel Combustion Methods

Titanium dioxide (TiO2) films were deposited on fluorine-doped tin-oxide (FTO) glass by sputtering and sol-gel combustion (SGC) coating methods and investigated with respect to their electrochemical luminescence (ECL) performance. The sputtered TiO2 films were denser than the SGC-deposited films, while the SGC films were found to be superior in porosity to the sputtered films. The charge transfer resistance (R-2) of the SGC (450 degrees C) TiO2-based cell was found to be lower than those of the sputtered TiO2-based cells. The SGC (450 degrees C) cell emitted a more intense ECL than the sputter (450 degrees C) cells. The threshold voltage at which the emission starts was 3.0 V for the SGC (450 degrees C) cell, which was lower than that (3.5 V) for the sputter (450 degrees C) cell. The efficiencies were 0.04 lm/W for the sputter (450 degrees C) cell (R-2 = 22.3 Omega, porosity = 27.2%) and 0.085 lm/W for the SGC (450 degrees C) cell (R-2 = 12.8 Omega, porosity = 65.8%). The SGC-deposited TiO2 films were found to be superior in ECL efficiency to the sputtered TiO2 films. (C) 2013 The Japan Society of Applied Physics