Design Of Flexible Capacitive Pressure Sensor Based On Mechanoluminescence Materials

Traditional capacitive pressure sensors are usually made of hard materials,and it is difficult to collect and transmit information on human body surfaces with irregular surfaces,robot surfaces,and so on.The flexible capacitive pressure sensor can solve this problem well.In this paper,a capacitive pressure sensor based on a porous PDMS/graphene flexible dielectric layer is prepared,and on this basis,Zn S:Cu²⁺and Li Nb O₃:Pr³⁺mechanoluminescence fluorescent particles are combined into the capacitive pressure sensor.The flexible capacitive pressure sensor of luminescent particles can quantify and map static and dynamic pressure by combining electrical response and optical response.It has obvious electrical response at low pressure and obvious light response at high pressure.And the influence of different factors on the performance of the device is studied.The details are as follows:The first chapter introduces in detail the classification and application of pressure sensors and the current research progress at home and abroad,as well as the application of mechanoluminescence materials and the research progress at home and abroad.In Chapter 2,the sensing mechanism of capacitive pressure sensor and the factors affecting the sensitivity of the sensor are introduced,the principle of capacitive pressure sensor and the principle of improving the sensitivity are analyzed,and the luminescence mechanism of mechanoluminescence materials is introduced.In Chapter 3,in order to reduce the manufacturing cost of the capacitive pressure sensor and improve the sensitivity and other performance of the capacitive pressure sensor,a"sandwich"structure flexible capacitive pressure sensor is designed based on the porous PDMS/graphene composite material,which converts the mechanical force signal into Electric signal output realizes pressure detection.Through research and comparison,it is found that the sensitivity and other properties of the prepared sensor have been improved.When the applied pressure is 0-50 k Pa,the sensitivity is 0.01844 k Pa^-1,and when the pressure is greater than 50 k Pa,the sensitivity is16.6×10^-4 k Pa^-1.In addition,the sensor has small hysteresis and good repeatability.After 1000cycles of pressure,the capacitance value can still output stably.Researched the application of the sensor,which can detect the bending of the finger very well.In Chapter 4,in order to increase the functionality and applicability of the capacitive pressure sensor,and to further improve the performance of the sensor,the Zn S:Cu²⁺mechanoluminescence material was prepared by solid-phase method and dispersed in PDMS to prepare a Zn S:Cu²⁺based The capacitive pressure sensor of mechanoluminescence fluorescent particles realizes a flexible capacitive pressure sensor that integrates pressure detection and visual injury warning.The sensor has a good electrical response under a small pressure,and a good light response under a higher pressure.The change of the sensor's luminous intensity with the increase of pressure and the change of the capacitance value with the increase of pressure are studied.The sensor has high sensitivity,the sensitivity of capacitive sensing is as high as 0.01267k Pa^-1,the sensitivity of luminescence sensing is 0.004k Pa^-1,the hysteresis is small,and the repeatability is good.In addition,the mouse can be monitored for pressing,and a bright green light will be emitted when the pressing force is too strong.In Chapter 5,in order to make the luminous performance of capacitive pressure sensors based on mechanoluminescence materials diversified,a flexible capacitive pressure sensor is designed based on Li Nb O₃:Pr³⁺mechanoluminescence materials.The sensor emits bright red light when subjected to high pressure,and the luminous intensity is different under different pressures.At the same time,the sensor has high sensitivity,the sensitivity of capacitive sensing is as high as 0.01846k Pa^-1,and the sensitivity of luminescence sensing is 0.00378 k Pa^-1.The hysteresis of the sensor is small and the repeatability is good.In addition,the application of the sensor's hand grasping fist test is also studied,which can well detect the fisting behavior of the hand.The palm force and the bending degree of the fist can be analyzed through the linear fitting function.When the fist is strong,it will emit a red light.