Active-Matrix Potentiometric Sensors with Low Operating Voltage of 0.05 V for High-Resolution Mapping of pH and Cellular Microenvironment

High-resolution mapping of pH can provide vital physiological information in environmental and biomedical applications. In this work, we develop active-matrix potentiometric sensors that integrate pH sensing and mapping capabilities by utilizing field-effect transistor (FET) sensors based on solution-processed oxide semiconductors. The FET sensors exhibit excellent electrical and pH sensing performance, characterized by high uniformity, low operating voltage (0.05 V), near-Nemst-limit sensitivity (59.4 mV/pH), and minimal drift rate (L2 mV/h). These characteristics enable the successful integration of a 16 × 16 active-matrix FET sensor array for high-resolution pH mapping. Furthermore, a transparent FET sensor array is achieved for bio-interface applications, where both the morphology and cellular microenvironment of living cells can be monitored. Our study presents an effective alternative approach beyond CMOS to realize active-matrix pH sensor arrays.