Preparation Of Samarium Oxide-based Nanomaterials And Their Humidity Sensing Researc

With the rapid development of intelligent technologies such as the Internet of Things and human-computer interaction,humidity sensors are playing an increasing role in agriculture,industry,medicine,environmental monitoring and aerospace.However,the development of highly sensitive and fast-response humidity sensing materials and devices remains a great challenge.In this thesis,Sm2O3 nanoflower and nanosheet were prepared by a simple solvothermal method,and the sensitivity performance of the materials was further enhanced by the compounding of KCl and TiO2 The work consisted of three main parts as follows:(1)Using samarium acetoacetone as samarium source,urea as precipitator,glycol,pegyl-400 and water as solvent,the nanoflower and nanosheet Sm2O3 materials with novel morphology were prepared by modulating the solvent ratio.The responses of the two sensor devices were 2253 and 1639 in the range of 11%to 95%RH,with response/recovery times of 0.3/8.4 s and 0.4/7.3 s,respectively,and both possess small humidity hysteresis(1.7%/1.0%).(2)Hydrophilic inorganic salts(KCl)were compounded with Sm2O3 nanoflowers and the effect of KCl content on the humidity sensitive performance of the composites was investigated.The results show that the KC1 Sm2O3 composite shows an extraordinary response,with the sensitivity being up to 127121 when the humidity varies from 11%to 95%RH,which is 60 times higher than that of the Sm2O3 nanoflower material,and exhibits an ultra-fast response(<0.1 s).Besides,applications of the sensor to human health,activity monitoring,non-contact sensing and alcohol count measurement are explored.(3)TiO2/Sm2O3 composites were prepared by a one-step solvothermal method and the effect of the TiO2 composite amount on the humidity sensitive performance of the material was investigated.The results showed that the best performance was achieved with 6 wt%TiO2 content of the composite compared to the pure phase Sm2O3 with a sensitivity of 45329 and a significant reduction in response/recovery time(0.2/3.6 s)when varying from 11%to 95%RH.In addition,the sensors prepared from TiO2/Sm2O3 composites also demonstrated good response in human respiration monitoring as well as non-contact sensing.