Estudio del rango de medida de sensores de humedad basados en películas de dióxido de titanio y óxido de grafeno

Abstract

Relative humidity is the percentage of water vapor in an environment with respect to its saturated value. Its measurement is made by relating a physical parameter that changes with humidity, such as electrical resistance, capacitance, refractive index, among others. The resistive sensors use hygroscopic materials with limited detection ranges and long response times. The present work investigates the electrical response of titanium dioxide films coated with graphene oxide, and compares them with individual materials. The devices were constructed by depositing the hygroscopic materials on interdigitated electrodes in a glass substrate. Atomic force microscopy, infrared and visible ultraviolet spectroscopy were used to characterized the films and materials. The electrical response of the devices was evaluated in a controlled humidity environment using impedance spectroscopy. The analysis of results determined that the conductance of the device with the hybrid material has an exponential relation with the relative humidity, a range of measure greater than the other humidity sensors, which covers values between 20% to 98% of relative humidity.