High‐Performance Capacitive Sensor Based on Polyphosphazene‐Modified InP Electrodes for Hydroquinone Detection

Abstract A high‐performance capacitive sensor is presented for the determination of hydroquinone (HQ) based on n‐type indium phosphide (n‐InP) electrodes with an electrochemically deposited polyphosphazene (PPP) coating. The integration of PPP with InP electrodes offers a previously unexplored approach to chemical sensing. The polymer film is deposited evenly and well examined by X‐ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and energy‐dispersive spectroscopy (EDS), which confirms the formation of a chemically stable and passivating interface. Capacitance–voltage (C–V) measurements in phosphate‐buffered saline (PBS) reveal a linear detection range of 1–100 µ m and a limit of detection (LOD) of 0.73 µ m ( n = 3), highlighting the sensitivity of the sensor. Selectivity tests indicate minimal interferences from structurally related phenolic substances such as catechol and phenol, corroborating the very high selectivity toward HQ. This capacitive sensing platform offers a promising approach for the rapid, sensitive, and selective detection of these hazardous chemicals, with vast potential for use in environmental monitoring and analytical fields.