Study on the design of ZnO/PANI composites and the mechanism of enhanced humidity sensing properties

ZnO/PANI composite humidity sensor was prepared by hydrothermal method . The first principles of density functional theory study the sensing mechanism. The calculation shows that the oxygen vacancy on ZnO surface is beneficial to the adsorption of water molecules. The {0 0 0‾1} crystal plane with the largest lattice oxygen number in ZnO has a strong adsorption capacity for water molecules, which is also conducive to improving the humidity sensitivity. PANI is easy to be combined on {0 1‾1 0} plane of ZnO, and it indirectly promotes the growth of {0 0 0‾1} plane, increasing the adsorption of water molecules and the proportion of H + and H 3 O + ions. In addition, the N–H group in ZnO/PANI enhances the H + conduction, which further improves the performance of the sensor. The results concluded that the proportion of lattice oxygen in humidity sensor is an important factor of humidity sensor sensitive detection.