Research On Precision Electrofluid Printing Technology And Its Application

With the improvement of people's living standards,the demand for wearable intelligent devices is increasing.Correspondingly,electronic devices should be increasingly flexible and integrated to recognize and transform vital signs such as body temperature,blood pressure,heartbeat and other signals more conveniently.Flexible electronics,which is the application of flexible technology to rigid equipment so that the equipment can stretch,bend and extrude,has a huge application prospect in sports and fitness,communication and entertainment,medical testing,aerospace and other fields.Inkjet printing technology,belongs to the field of printing electronics,is one of the mainstream technologies for manufacturing high-performance flexible electronic devices.As an additive manufacturing process,it directly deposits the selected functional materials onto the target substrate to form the desired pattern,which saves the material and reduces the cost.The process is simple and environmentally friendly.It can be used for roll-to-roll mass,large-area and high-speed production.And it can achieve flexibility.So far,most of the capacitors made by inkjet printing technology are only printed electrodes,while the dielectric layer is made by other processes.Only a few of capacitors,which are allinkjet-printed,are made by traditional inkjet printing technology which has low resolution.Electrofluid jet printing technology is a kind of inkjet printing technology,with high resolution printing,applicable to a wide range of solution viscosity and other advantages.In this paper,electrofluid jet printing technology is used to optimize the production process of all-inkjetprinted capacitors,and high-performance flexible capacitors are produced by printing highresolution patterns.The specific contents are as follows:(1)By adding ethanol solvent to nano-silver ink,the ratio of nano-silver ink to ethanol by volume ratio of 1:0.3 is optimized to solve the Bulge phenomenon in the process of silver wire printing;The silver wires are printed on ITO,silicon wafer,PET,boron nitride and pixel substrate respectively.Finally,the fine silver wires of 4.5 ?m are printed on ITO substrate;Then electrohydrodynamic printing equipment is used to prepare the auxiliary electrode of topemitting OLED,and the silver wire of 8.7 ?m is printed on the substrate.The electrical properties such as the threshold voltage and other parameters were measured to investigated the influence of electrofluid jet printing on of different types of TFT,which provided a reliable basis for the structural design of TFT assisted electrode preparation using electrofluid jet printing.At the same time,the process of electrofluid jet printing equipment is explored,and the printing parameters of the electrofluid jet printing equipment are optimized.(2)The suitable dielectric material is selected for doping to fabricate high performance dielectric constant thin film by method of solution,and the solution suitable for printing is prepared by optimizing the formula of dielectric material.Equipments of electrohydrodynamic printing and screen printing are used to print electrodes and dielectric materials on the PET substrate in turn,so as to realize the fabrication of large-area flexible capacitors with full printing.And the capacitance value is measured by impedance analyzer;Capacitors with different pattern dielectric layers were prepared by patterning the dielectric layer and increasing the capacitance value by about 4 times.The influence of different pattern on the capacitor capacitance is explored,which lays a solid foundation for the preparation of high sensitivity and high performance flexible capacitive sensor.