Highly stable flexible ozone gas sensors using Mn3O4 nanoparticles-decorated IGZO thin films through the SILAR method

Metal or semiconductor nanoparticles (NPs) can enhance the device performance of gas sensors due to their high surface area and unique electronic properties. However, this method requires additional thermal bonding with high temperatures to secure the NPs, making it unsuitable for flexible substrates. In this study, we develop a room-temperature flexible ozone (O3) gas sensor using Mn3O4 NPs on an amorphous InGaZnO (a-IGZO) film. The Mn3O4 NPs are synthesized by a successive ionic layer adsorption and reaction (SILAR) method at low temperatures. The sensor with Mn3O4 NPs exhibits a gas response of 4.06 against 5 ppm O3 gas at room temperature, which is much higher than that of its pristine counterpart. It also shows excellent selectivity for O3 over toxic gases and maintains stability over 60 days, with reproducible folding even after 500 bending cycles. Thus, the combination of SILAR-synthesized Mn3O4 NPs and a-IGZO films provides an effective way to fabricate flexible O3 gas sensors.