Sensors have become an integral part of all the activity of modern human being. Amongst the sensors, humidity sensor is a vital requirement of human life and industrial applications and therefore needs exact monitoring. Although humidity sensors designed from ceramic materials, polymers and composites have been studied, ceramic sensors are preferred for their chemical and physical stability in an environment, which is suitable for its applications, processing ability and possibility of achieving predetermined properties. Although many oxides such as SnO2, 1 ZnO, TiO2, 3 ZrO2 4 SiO2 5 are being studied for the development of humidity sensors, the research for newer methods and the materials is unending because of specific requirements of various applications in terms of sensitivity, selectivity, response time, low cost of manufacture, compactness and microprocessor compatibility. Moreover, it is almost impossible to develop an ideal universal humidity sensor for all applications. TiO2 based humidity sensors are studied vigorously, as it is likely to show better sensitivity because of its hydrophilic property. It is studied more in thin film form. However, it is reported that thin film sensors show lower sensitivity than those shown by porous ceramic sintered counterparts. TiO2 is known to have a hysteresis in humidity sensitivity curve. It was thought that the use of additives would be useful to get over this drawback. The additives are reported to minimize the hysteresis in TiO2 humidity sensors. 10
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Nov 1, 2016
Wesley Becari + 3
Open Access