| Summary: | A variety of uses for the commercial pH sensor have been established; one of them is figuring out the pH of plant soil. The accuracy of the commercial pH sensor and the long-term reliability of the device, however, appear to be questionable. In this paper, we demonstrate highly sensitive extended-gate field effect transistor (EGFET) pH sensors that have been examined in pH buffer solutions. The sol-gel spin coating process was employed for fabricating TiO2 films and TiO2:PVP composite films on an indium-doped tin oxide (ITO)-coated glass substrate to form two distinct sensing electrodes for the EGFET. The pH detection performance was investigated using a variety of pH buffer solutions ranging from pH2 to pH12. In contrast to TiO2 films (49.69 mV/pH), the TiO2:PVP composite films showed a higher sensitivity of 63.2 mV/pH. To evaluate the stability capabilities of the EGFET pH sensor, hysteresis and drift studies were conducted. It was found that the composite TiO2:PVP films were able to achieve a distinguished low hysteresis value of 10 mV and a low drift rate of 11 mV/h compared to TiO2 films and previous reported studies. Further analysis of repeatability measurement was carried out three times for the composite films, resulting in a constant deviation of 0.002 that corresponded to low pH values. © 2024 Penerbit UTM Press. All rights reserved.
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