Research On Flexible Capacitive Sensor Based On Nanocomposites

Flexible sensors,as one of the key elements of wearable electronic devices,have drawn a lot of attention in academia and industry due to the rapid development of the Internet of Things and artificial intelligence technology.This can be attributed to their numerous potential applications in the fields of medicine,tactile perception,human-computer interaction,and other areas.Gaining higher sensitivity has long been one of the main objectives of research into flexible sensors.Unfortunately,the high cost of manufacturing microstructures,the difficulty of the fabrication process,and the unsuitability for mass production are impeding further advances in sensing capability.In order to solve the above problems,black phosphorus-gold and titanium carbide-gold nanocomposites combined with porous Ecoflex and sponge microstructure dielectric layers were used to fabricate two types of flexible capacitive sensors with high sensitivity,fast response,excellent dynamic performance and good repeatability were fabricated,and the function of detecting weak signals was realized.The specific research content includes:（1）This work focused on designing a flexible capacitive sensor based on a black phosphorus-gold/Ecoflex composite dielectric layer.The sodium bicarbonate and acid neutralization reaction forms a porous microstructure and embedded nanocomposites in the Ecoflex substrate that make up the sensor.Utilizing the mechanical properties of porous Ecoflex dielectric layer and the superior electrical properties of black phosphorus-gold nanocomposites,the capacitive sensor has good performance of high sensitivity(0.0984 k Pa^-1@0-2.5k Pa),low response time（45 ms）,stability over 2500 repeated cycle tests and low pressure detection limit of 1.5 Pa.（2）This study further designed a flexible capacitive sensor based on titanium carbide-gold/sponge composite dielectric layer.The sensor is made by modifying titanium carbide-gold nanocomposites on a sponge skeleton with more and uniform pores,combined with interdigital electrodes printed by laser-induced graphene technology.The sensor performance of the prepared sensor has been further improved,it has high sensitivity(0.4177 k Pa^-1@<0.88 k Pa),low response time（32 ms）,durability of 3000repeated loading and unloading tests,and ultra-low pressure detection limit of 1.0 Pa.（3）The two kinds of prepared capacitive sensors in this study were used in the areas of tactile perception and medical health.The relevant physiological signals such as wrist bending,finger bending,human breathing,swallowing,blinking and human pulse were monitored,and the vertical pressure generated by activities such as mouse clicking,air blowing and grasping objects were also tactilely sensed.At the same time,the working ability of the sensor based on black phosphorus-gold/Ecoflex composite dielectric layer in the bending state was explored.And the non-contact perception of the surroundings was extended to the application scene based on titanium carbide-gold/sponge composite dielectric layer sensor.