Study On Self-assembled Thin Films Of Organic Semiconductor And Their Gas Sensing Performances

Organic semiconductors have been widely studied,due to their simple synthetic method and low cost.Moreover,gas sensors based on organic semiconductor can detect target gases at room temperature or relatively low operating temperature.However,organic semiconductor materials have many disadvantages such as complex film forming technology,poor compatibility between organic thin films and sensor devices,low sensitivity and low response rate.These defects limit the development and application of organic semiconductor gas sensors.Herein,in order to research and optimize the gas sensing characteristics of organic semiconductor gas sensors,cobalt phthalocyanine?CoPc?,copper phthalocyanine?CuPc?and polyaniline are selected as sensitive materials in this paper,and investigate their properties as gas sensors.Main achievements are as follows:?1?Cobalt phthalocyanine was synthesized based on the route of phthalic anhydride and urea,and then cobalt phthalocyanine thin films were prepared by method of gas-liquid interface self-assembly.The optimum gas sensing performances of cobalt phthalocyanine thin films for NO₂ were obtained by thermal excitation.Also,the cobalt phthalocyanine thin films were excited by ultraviolet light,and the room temperature detection of NO₂ was realized.?2?In-situ growth of polyaniline hollow sphere array films on the electrode using polystyrene spheres as template.The room temperature detection performance of polyaniline hollow sphere array was studied experimentally.Through different hydrophobic polystyrene templates,the hydrophobic effect was found to promote the formation of polyaniline hollow spheres.Different organic acids were used to show that the gas sensing properties of polyaniline were affected by organic acids.?3?Inorganic/organic composite materials were used to prepare Cu₂O/CuPc thin films as gas sensing materials.It is found that the Cu₂O/CuPc composite film has the advantages of instantaneous response,high sensitivity and high resolution,and thus provides a new way for the development of high performance TMA gas sensors.Based on the above contents,in this paper the fabrication process and gas sensing performances of gas sensors based on organic semiconductors are systematically studied,which provides an effective design method for the preparation of organic semiconductor sensors with high performance.