Highly Selective Self-Powered Organic-Inorganic Hybrid Heterojunction of a Halide Perovskite and InGaZnO NO2 Sensor

Self-powered sensors can lead to disruptive advances in selfsustainable sensing systems that are imperative for evolving human lifestyles. For the first time, we demonstrate the fabrication of a heterojunction sensor using p-type hybrid-halide perovskites (CH3NH3PbBr3) and an n-type semiconducting metal oxide thin film [InGaZnO (IGZO)] for the detection of NO2 gas and power generation. Combining the excellent photoelectric properties of perovskites and the remarkable gas-sensing properties of IGZO at room temperature, the devised sensors generate open-circuit voltage and modulate according to the ambient NO2 concentration. The major challenge in devising self-powered gas sensors is to attain harvesting capability and selectivity simultaneously, owing to perovskites reactivity in the presence of oxygen and humidity. In this work, we developed a novel approach and fabricated a heterojunction sensor using parylene-c as an additional layer to curb the cross-sensitivity and to enhance the selectivity of the sensor. Even under the low concentrations of NO2, the developed sensor exhibits remarkable sensitivity, selectivity, and repeatability. The devices are sensitive and robust even under extreme humidity conditions (80% R-H) and synthetic air. The devised sensor configuration is one way to eliminate the cross-sensitivity issue of the perovskite-based devices and serves as a reference for the development of selfpowered sensors.

Automated summary

This study demonstrates the fabrication of a self-powered sensor using hybrid-halide perovskites and semiconducting metal oxide thin film for detection of NO2 gas and power generation. The sensor shows remarkable sensitivity, selectivity, and repeatability even under low concentrations of NO2, and remains sensitive and robust under extreme humidity conditions. The developed sensor configuration serves as a reference for the development of self-powered sensors by eliminating the cross-sensitivity issue associated with perovskite-based devices.