| With the rapid development of artificial intelligence and flexible wearable devices,flexible sensors are also developing at a high speed,showing great development potential in many fields such as medical treatment and industry.The flexible sensor of low cost,high performance,visual response is one of the great challenges in this field.A low cost and high performance flexible pressure sensor was prepared by a relatively simple process by mixing low cost carbon black（CB）and multi-walled carbon nanotubes（MWCNTs）in porous structure.A flexible mechanoluminescent sensor with good sensing performance and visual response was prepared by using carbon quantum dots（CQDs）,MWCNTs and microcrack structures.The main research results are as follow:Based on the foam template method and ultrasonic bath method,a 3D porous CB/MWCNTs conductive composite films was prepared,and a flexible pressure sensor was obtained by assembling it with a fork electrode.The sensor model was established and its working mechanism was analyzed.The effects of mixed conductive filler ratio,fork electrode shape and line width and line distance on sensor performance were explored.Mechanical,electrical performance tests and human movement monitoring were carried out on the test platform.The results show that the best performance was obtained when the weight ratio of CB to MWCNTs is 1 and the line width of the rectangular cross finger electrode is 60μm.The sensitivity is 3.57 k Pa-1 in the pressure range of 0 to 21 k Pa,and has a durability of over 6000cycles.In addition,the sensor can achieve good response under different pressures,and also shows great potential in the simulation of grasping and manipulating objects.The sandwich CQDs/MWCNTs flexible strain sensor was prepared by solvothermal reaction,static stratification and ultrasonic bath,and the effects of MWCNTs contents on the performance of the sensor were explored.The mechanical,electrical and fluorescence characteristics of the sensor were measured by the test platform and the fluorescence spectrophotometer,and the practical application monitoring was carried out.The results show that when the content of MWCNTs is 6 g/L,the sensor shows good sensing performance and fluorescence effect.The sensitivity is 0.31 in 130%strain range,which can be used to monitor human movement at different scales.The microcrack CQDs/MWCNTs flexible mechanoluminescent sensor was fabricated based on the layered design method,and the effects of different fluorescent carbon quantum dots on the performance of the sensor were explored.The results show that the addition of fluorescent layer has little effect on the sensor performance.The sensor has a sensitivity of approximately 13 in the 60%strain range and has over 800 cycles of cycle durability.Combined with the analysis and test,it is found that the introduction of micro-crack structure not only retains the original sensing characteristics of the sensor,but also adds a good mechanoluminescent effect,which further expands the application range of the sensor.In summary,this study prepared three kinds of flexible piezoresistive sensors through structural design and material selection,explored the influence of conductive materials on sensor performance,and successfully applied it to human motion monitoring,which has certain guiding significance for the development of flexible piezoresistive sensors.In addition,the mechanoluminescent sensors based on CQDs/MWCNTs provide a new idea for the future development of visual flexible piezoresistive sensors. |
PDF Full Text Request