Photochemically Activated Mn₃O₄ Thin Films That are Produced Using SILAR for Highly Stable Flexible Gas Sensors

We report on a highly stable p-type Mn3O4 flexible gas sensor for room-temperature detection of O3. The Mn3O4 film is deposited by the successive ionic layer adsorption and reaction (SILAR) method at low temperatures and photochemically activated by an ultraviolet (UV) light-emitting diode (LED) at room temperature. The Mn3O4 gas sensor exhibits gas response, response time, and recovery time of 1.65, 159, and 130 s, respectively, against 5-ppm O3 gas at a UV intensity of 20 mW/cm2. It enables high selectivity for O3 gas against various toxic gases even at room temperature. Moreover, the flexible gas sensor exhibits negligible degradation over 60 days and folds reproducibly after repeated bending for 300 cycles. These results strongly support that an Mn3O4 film deposited by SILAR is a good candidate for room-temperature flexible gas sensors for the applications of wearable devices.