High-Performance Solution-Processed La₂Ti₂O₇ Sensing Film for a Capacitive Electrolyte–Insulator–Semiconductor pH Sensor

This work presents a comparison between the La2O3 and La2Ti2O7 sensing membranes for solution-based capacitive electrolyte-insulator-semiconductor (EIS) pH sensors. The La2O3 and La2Ti2O7 sensing membranes were fabricated through a simple spin-coating method. The structural characteristics of these sensing membranes were examined by using X-ray photoelectron spectroscopy and X-ray diffraction. The La2Ti2O7 EIS sensor made using the spin-coating process demonstrated a higher sensitivity of 70.60 mV/pH, a smaller drift rate of 0.14 mV/h and a lower hysteresis voltage of 1 mV, as compared to the La2O3 EIS sensor.