Humidity is a critical environmental parameter for several production processes and its control/monitoring is of great importance in maintaining the quality of goods and products. In this context, metallic oxide ceramic nanostructures are materials of great technological interest in the fabrication of moisture sensors because they have good chemical/structural stability and high surface area/volume ratio. The electrical response of these sensors relates to the chemisorbed and physisorbed layers of water molecules on the surface of the ceramic particles and to the capillary condensation of water in the microscopic pores between the particles. Based on these aspects, this work presents the fundamentals, electrical/electronic properties, influence of dopants, novel preparation procedure by electrospinning and perspectives of application of TiO 2 :WO 3 metal oxide heteronanostructures as humidity sensors.
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