Preparation And Optoelectronic Properties Of Flexible Conductive Films Based On Screen Printing Technology

With the rapid development of optoelectronic technology,the application scenarios of flexible wearable electronic products have become more extensive,and the market demand for flexible conductive films has also increased.Indium tin oxide(ITO),the traditional material for the preparation of conductive films,has limited the large-scale production of flexible conductive films due to its expensive and fragile characteristics.New conductive materials and manufacturing processes have become urgent problems to be solved.The combination of printing techniques with solution-processable conductive materials provides a promising solution to the scale-up problem.Printed electronics technology can not only achieve mass production,but also has the characteristics of Environment friendly and low cost,which is conducive to the development of flexible electronic equipment.Among the existing printing methods,screen-printing is the most widely used technology and is favored by the industry for its low cost,easy operation,and high repeatability.In terms of conductive materials,silver nanowires(AgNWs)are considered as high-quality materials for the preparation of flexible transparent conductive films due to their excellent electrical conductivity,thermal conductivity and mechanical properties.For flexible opaque conductive films,carbon paste has attracted wide attention due to its low cost and stable performance.In this paper,firstly,the research progress of printed electronics technology was introduced,and then the principle and process of screen printing were summarized.The main components of conductive inks and related properties were analyzed theoretically.Secondly,AgNWs which meet the conditions of screen printing were prepared by polyol solvothermal method and ultrasonic induced fracture method.Based on the analysis of experimental results,the formulation of AgNWs-based conductive ink and conductive carbon paste was proposed.Finally,with the assistance of the screen printing process,AgNWs transparent conductive films And conductive carbon paste film obtained by printing conductive ink on a substrate.The specific experimental works completed are as follows.(1)AgNWs with uncontrollable size were prepared by polyol solvothermal method.The effects of ultrasonic power,ultrasonic time,and the concentration of AgNWs ethanol solution on the size of fractured AgNWs were studied.The experimental results show that the increase in ultrasonic power and ultrasonic time will lead to AgNWs.The degree of fracture intensifies and the average length decreases.However,when the length of AgNWs decreases to 0.3 ?m,the limit value of ultrasonically induced fracture is reached.After that,the average length of AgNWs does not change with the increase of ultrasonic power and time.Under the experimental conditions of fixed ultrasonic power and ultrasonic time,the average length of AgNWs has a positive correlation with the concentration of AgNWs ethanol solution.(2)By studying the effects of conductive substances,solvents,adhesives,and additives in conductive inks on the physical and chemical properties of conductive inks,the proportion of each component was reasonably adjusted,and finally AgNWs-based conductive inks and conductive carbon paste that meet the requirements of screen printing were prepared.(3)The above conductive ink was prepared into AgNWs transparent conductive film and conductive carbon paste film by screen printing technology.The sheet resistance and light transmittance of the conductive film were characterized.Furthermore,After the influence of the factors such as the amount of conductive ink and annealing temperature were analyzed,the stability evaluation of conductive films was proposed based on performance test results after multiple large-scale deformations.