Study On Humidity Sensing Properties Of Metal-organic Frameworks Materials Of Cu₃（BTC）₂

Water is the source of life. Body is70percent water. Water has great influenceon our production and life, and it is important to measure the humidity. The humiditysensors are used to measure the humidity. It works by the physical property, such asresistance or capacitor, changing after the humidity material absorbs water. Wemeasure the change to know the humidity of air. With the development of science andtechnology, the measurement of humidity is widely need in growing number of fields.The humidity sensor with higher performance and better stability is need. Thedevelopment of new humidity sensing materials has always been an importantresearch direction of humidity sensor. Metal-Organic Frameworks materials havelarge specific surface area, porous structure and stability is better. It makes a lot ofattentions. By its Characteristic, there is a wide prospect in humidity sensor by usingMetal-Organic Frameworks compounds.In this paper, Cu3(BTC)2crystal is synthesized by a solvothermal method. Makesamples with different mass ratio by mixed. The samples were characterized by X-raydiffraction (XRD) and scanning electron microscope (SEM). Then the samples weremade into sensors and the sensors were measured. The principle is analyzed.The sensor made by pure Cu3(BTC)2has little response. When the LiCl wasmixed by5%mass ratio, the sensor has a little response. But it is still weak. When themass ratio was10%, the sensor shows a better response. When the mass ratio was20%, the performance of the sensor is the best. There are three orders of magnitudewith the change of resistance. The sensor shows high sensitivity at all relativehumidity. The sensor with30%LiCl mass ratio shows the similar performance withthe20%one.The humidity hysteresis of the sensors with10%,20%,30%LiCl is7%RH,5%RH,8%RH, respectively. The sensor with20%LiCl shows the best performance. The response time of the sensor with10%LiCl is90s, and the recovery time is2min. The response time of the sensor with20%LiCl is9s, and the recovery time is25s, which are much shorter. The sensor with30%LiCl has the similar response andrecovery time which are11s and24s respectively. The results show that LiCl-loadingnot only improves the performance of the humidity properties of humidity sensor, butalso makes the response and recovery time shorter.We analyzed the complex impedance property at different relative humidity tostudy the sensing mechanism. And outlook is raised as for the potential ofMetal-Organic Frameworks in humidity sensing.