Study On Design And Performance Of Multi-functional Pressure Sensor By Structure Modification

The rapid development of consumer electronics,and the continuous emergence and performance improvement of various sensing and detection devices,which provided fast and convenient monitoring of human daily health.Among them,wearable pressure sensors are devices that can convert external pressure into electrical signals,and have potential application value due to their excellent characteristics such as high sensitivity.However,at present,pressure sensors have problems such as single functionality,limited detection range and sensitivity.To solve these problems,a device with integrated functionality is designed through material and device structure regulation.In this work,we design the pressure sensors with different structures by studying 3D,stacked,and multi-layer structures,and conducts research and analysis on their various performance.The main research contents and conclusions are as follows.（1）A systematic study of the microscopic morphology of BT flower-like structured ceramic powder,BT/PVDF composite film and hydrophobic film was conducted to investigate the effects of different composite ratio materials as well as the external force application environment on the output performance of the devices.The results show that the BT flower-like sensor loaded with hydrophobic membrane can detect a tiny signal of a drop of water falling low with a sensitivity of up to 0.13 V·k Pa^-1,a response time of 78 ms,a recovery time of 98 ms,and a stable output voltage during 1000 cycles.（2）To systematically study the output performance of piezoelectric and piezoresistive sensors with 3D sponge structure under different material content and different external factors.The microstructures of MXene,MXene complexes,and single-crystal Zn O materials are also characterized and analyzed.The results show that the piezoresistive sensors have a maximum sensitivity of 3.5-6.4 k Pa^-1 over a wide pressure detection range of 0-61.12 k Pa.The piezoelectric sensors with Zn O nanorods can output a high voltage of 101 V,a maximum output power of 10μW and a piezoelectric sensitivity of 4.37 V·k Pa^-1.They can also monitor human footsteps,hand clapping,finger flexion and elbow bending movements in real time while the piezoelectric sensor can drive the piezo-resistive sensor operation.（3）To investigate the microscopic morphology of hybrid power generation devices with cascaded triboelectric and piezoelectric cells.The output performance of BNBT/PVDF and BNN/PDMS films with different processes and compound ratios and hybrid power generation devices were investigated.120 V open-circuit voltage could be generated by the hybrid power generation devices prepared from BNBT/PVDF films with 15 wt.%BNBT and BNN/PDMS films with 10 wt.%BNN,which is higher than that of piezoelectric（20 V）and triboelectric（92 V）combined.When the external load resistance is 50 MΩ,the maximum output power is 1.3 m W,and 50 yellow LEDs can be driven.（4）Systematically study the surface microstructure of integrated pressure sensors with piezoelectric,thermochromic,and piezoresistive functions.Extensive experiments are done on the effects of different composite materials and external environment on the sensor to achieve real-time color change of the sensor to meet the needs of high temperature working environment.The results show that its temperature visualization function can be displayed from blue at 30°C to white at 150°C with a maximum temperature voltage change sensitivity of about 0.7 V·°C^-1.The maximum detection range of the piezoresistive sensor is 300 k Pa with a maximum sensitivity of 0.835 k Pa^-1.The output voltage of the piezoelectric sensor is about 80 V with a piezoelectric sensitivity of 1.398 V·k Pa^-1.and piezoelectric and piezoresistive are complementary to each other and do not affect each other.（5）Systematic study of multilayer type electrodes,surface microstructure of piezoelectric material integrated pressure sensors.The effects of different content of piezoelectric materials and external environment on the piezoelectric sensors are analyzed.The design of the polymer makes the device piezoelectric and electrodes with thermal repair function,which makes it a possibility to work again after the device is damaged.The results show that the sensor is heated to 70°C in 10 minutes under light conditions to repair its own defects.The output voltage remains essentially unchanged after stretching and healing 20 times.High sensitivity(2.09 V·k Pa^-1),short response time（66 ms）,high maximum output voltage（61 V）and power（30μW）were also achieved.