Study on using commercial touch panel film as the gate electrode for ISFET-based pH sensor

摘要

This study developed a high performance Ion-Sensitive Field-Effect-Transistor (ISFET) based pH sensor utilizing commercial Touch Panel Film (TPF) as the gate electrode. The TPF was composed of a PET substrate both sides symmetrically coated with a niobium pentoxide, a silicon dioxide and an indium tin oxide (ITO/SiO_2/Nb_2O_5) layers by industrial roll-to-roll sputtering process, which qualified by industrial quality specifications was approved suitable for commercialized products development. The gate electrode was connected to a MOSFET by a plug-in design such that the developed pH sensor could be replaced in seconds. From the measurements, the TPF-based pH sensor had high sensitivity of 59.2 mV/pH with R~2 value of 0.9948 in buffer solution pH range between 3 and 13, which was almost identical to the Nernst theoretical response. Meanwhile the response of the developed sensor was fast (1s) with good stability (C.V. <1%). This study had developed a flexible TPF-based pH sensor which was of high performance and suitable for disposable biosensor applications.