Development of the tin oxide pH electrode by the sputtering method

In previous investigations, different preparation methods of the pH electrode influenced pH-sensing characteristics. Hence, this study attempted to employ the tin oxide (SnO2) membrane in fabricating a pH electrode by the sputtering method, whose substrate was based on the indium tin oxide (ITO) glass substrate, and employing the two-point calibration method proved the pH-sensing characteristic. Furthermore, to define the effective sensing area of the pH electrode, experimental results and simulation results were employed. According to results, enough sensing area increased the pH sensitivity stability of the pH electrode and 4 mm2 was the effective sensing area in fabricating a SnO2 pH electrode. After the effective fabrication process was proved, the SnO2 pH electrode had linear pH response and higher stability as it compared with the commercial pH glass electrode. Consequently, this study investigated an effective SnO2 pH electrode by the sputtering method.