Silanization of Porous Silicon Surface for Ion-Sensor Applications

This paper shows the possibility of using modified porous silicon (PS) surface by silanization as a transducter material for ion-sensor applications. The passivated electrode is characterized through cyclic voltammetry and through capacitance measurements showing good insulating properties of the aminopropyl-triethoxysilane (APTS) monolayer. The passivated electrode presents a linear pH response with a slope close to 61 mV per pH unit. This sub-Nernstian response is correlated with physical parameters of porous silicon samples and the amine site at the electrode surface. In a second step, the silanized PS electrode has been functionalized with tertiobutylcalix[4]arene (CA) molecules. We observed a sub-Nernstian response (157 mV/pNa) showing the high potentiality of the silanized PS electrode as a base for sensitive ionic potentiometric sensors.