Controllable Preparation Of Molybdenum Selenide Nanomaterials And Its Room Temperature Gas Sensing Properties

In recent years,transition metal disulfides(TMDs)accelerate the research and development of various fields including gas sensors due to their intriguing electronic,mechanics,optical,magnetic and chemical properties.Among the TMDs,MoSe₂ is an emerging semiconductor material matures which has matured in field effect transistors and lubricants,etc.But there are relatively few applications in the field of gas sensors,especially room temperature gas sensing.This paper explores the potential of MoSe₂ as a high-performance room temperature gas sensing material based on the gas-sensing research of other TMDs.The main work of this thesis is as follows:1.We synthesized flower-like MoSe₂ nanomaterials using a hydrothermal method.The results confirmed that the MoSe₂ has a certain gas sensing performance,but the response value at room temperature was low,which was difficult to meet the requirement of practical application.Take a series of advantages of two-dimensional(2D)materials for room temperature gas sensors,we utilized a simple and rapid liquid-phase exfoliation method to prepare the desired 2D MoSe₂ nanosheets.2.The liquid phase exfoliation effects of different dispersants were explored.It was found that compared with other dispersants,the 2D nanosheets obtained by ethanol exfoliation were relatively smaller and thinner.The prepared device showed the highest response to NO₂ gas.3.The MoSe₂ nanosheets obtained by ethanol exfoliation were subjected to detailed characterization and gas sensing properties tests.The results showed that the obtained gas sensor had significant gas-sensitive performance for NO₂ at room temperature.The response of few-layers MoSe₂ nanosheets towards 10 ppm NO₂ was 17 times greater than the bulk MoSe₂.In addition,the device exhibited a series of excellent performances such as low detection limit(50 ppb),outstanding repeatability and good long-term stability(more than 60 days).The innovation of this thesis is that a simple,efficient,and environmentally friendly method for preparing high-performance room-temperature gas sensors based on MoSe₂ sensing materials was developed.The response value of the prepared MoSe₂ nanosheets to NO₂ is much higher than the reported values of room temperature gas sensors based on pure 2D materials.The superior performance of the gas sensors makes 2D MoSe₂nanosheets a potential candidate for room temperature gas sensing applications,while also providing feasible ideas for the development of high performance room temperature gas sensors based on other 2D TMDs materials.