pH sensor using nanoelectrodes in organic semiconductor

A new pH sensor using nanoelectrodes in organic semiconductor P3HT (regioregular poly(3-hexylthiophene)) has been designed, fabricated and characterized in this work. In this sensor, the organic semiconductor is directly exposed to pH sample solution, and an electrical field is applied to drive the protons in the solution to the polymer surface. The accumulated protons at the interface between organic semiconductor and solution change the electron density at organic semiconductor surface, so that the conductivity of the organic semiconductor film is modulated. In order to improve the sensitivity of sensor, P3HT is coated on the interdigitated array nanoelectrodes, and the conductivity of P3HT between two bands of electrodes is measured for pH characterization. A good conductivity modulation by the proton concentration or pH value is shown in the sensor testing.