Highly sensitive and selective H2O2 sensors based on ZnO TFT using PBNCs/Pt-NPs/TNTAs as gate electrode

Abstract A highly sensitive and selective sensor is urgently needed in many practical H2O2 detection, such as water quality monitoring, quality control of food products, and so on. However, the traditional three electrode system limits its further development in recent years due to its difficulty in miniaturization and integration. To effectively improve its sensitivity and selectivity, highly-ordered TiO2 nanotube arrays (TNTAs) are modified with Pt nanoparticles and Prussian blue (PB) nanotubes and creatively combines with thin-film transistor (TFT) based on ZnO to prepare an electrochemical sensor. The sensor uses PBNCs as recognition units for the specific detection of H2O2, and the generated electrical signal is amplified by TFT. Thus, a highly sensitive and selective H2O2 sensor is achieved. The detection limit of the sensor is as low as 5.19 nM, which is three orders of magnitude lower than the conventional electrochemical detection methods using the same electrode. The sensor also possesses wider linear detection range of 0.1 - 50 μM and 50 μM - 5 mM comparable to that of other reported H2O2 sensors. Besides, the sensor has good selectivity for H2O2 in the presence of common interferences such as ascorbic acid, uric acid, glucose, and dopamine. Furthermore, the device presents good reproducibility and exhibits good long-term stability over 27 days of continuous measurement. This study offers important insights for the rational design of sensors with high sensitivity and selectivity.