Research On Humidity Sensors Based On Metal-organic Framework MIL-101(Cr)

With times changing,people's living standard and quality,as well as the requirement of living environment,have been improved.So in the actual production life,different occasions need different requirements of humidity in the aspects of industrial control,environmental monitoring,atmospheric and meteorological,which need to be controlled and monitored appropriately,and the importance of humidity sensors is indispensable.As the soul part of humidity sensor,humidity material are increasingly diversification.For the study of the humidity sensors,people are mostly focused on the development of new materials and research.As a new material,metal organic framework materials(MOFs)began to take shape in the area of humidity sensitive material.With the high porosity,large surface area,diverse structural characteristics,MOFs are widely used.Based on the above background,the paper first introduces the concept of humidity and related concept,and describes the principles,classification,characteristics and basic research progress of humidity sensor.Furthermore introduce the new humidity sensing material-metal organic framework materials(MOFs)which are used in this experiment from development process to the application.Nanoporous material-metal organic framework MIL-101(Cr)was chosen as humidity sensing material in this paper.MIL-101(Cr)is Cr-based carboxylate with super tetrahedral structure.The framework is made from the linkage of 1,4-BDC anions as six edges and Cr-trimers as four vertexes,which delimits two types of porous cages with inter free diameters of ~29 ? and ~34 ?.MIL-101(Cr)possesses extremely high specific surface areas and porosity.The abundant hydrophilic active sites(chromium oxo-clusters)on the framework surface can also adsorb water molecules easily.What is more,good water stability of MIL-101(Cr)in comparison to other MOFs ensure structural integrity in high humidity environment.The above introductions are the reasons why we choose MIL-101(Cr)as humidity sensing material.Furthermore,we synthesized LiCl/MIL-101(Cr)with Li+ doping treatment to improve the humidity sensing properties.The main contents of this paper are shown as followed:1?The metal organic framework MIL-101(Cr)was synthesized with HF-free solvothermal method.And the materials are coated on the interdigital electrode by the coating method and produce a resistive typed humidity sensor.The impedence of sensor changed more than three orders of magnitudes in the range of 33-95% RH.And the humidity sensor based on MIL-101(Cr)possess prominent stability and selectivity for humidity.2?The humidity sensor based on LiCl/MIL-101(Cr)was successfully fabricated by doping LiCl with different content in metal organic framework MIL-101(Cr).The experimental results indicate that humidity sensor based on LiCl/MIL-101(Cr)shows better linear and higher sensitivity when the doped proportion is 10 wt%.The impedance of sensor changed four orders of magnitudes in the whole range of 11%-95% RH.From the above,we fabricated high performance humidity sensor based on MIL-101(Cr).And the properties of LiCl/MIL-101(Cr)humidity sensor were improved with Li+ doping treatment,which provides a theoretical basis for improvement of humidity materials by ion doping.