Research On Fabrication Process Of Flexible Organic Electrochemical Transistor Biosensors

Flexible Organic Electrochemical Transistors（FOECT）biosensors have broad application prospects in the field of biosensing due to their high sensitivity,good biocompatibility,low cost,and light weight.Printing technology is the most effective method for low-cost,large-scale manufacturing of FOECT devices.However,the current research on printing technology in FOECT device manufacturing is still insufficient,and there are problems such as imperfect manufacturing process and single manufacturing method.Therefore,this paper has carried out researches on printing parameters debugging of FOECT devices based on printing technology,manufacturing process optimization,device structure design,developed a glucose sensor and a FOECT device platform as an enzyme biosensor.The main research contents are as follows:（1）The research on the manufacture of FOECT devices by pneumatic direct writing printing technology was carried out.The parameters of each part of the FOECT device printed by the pneumatic direct writing printing technology are studied,and the printing and heat treatment parameters that have a great influence on each material are optimized,and the good printing of each part of the material is realized.A FOECT device completely manufactured by pneumatic direct writing printing technology was designed,a complete manufacturing process was developed,the device manufacturing was completed,and the transfer and transconductance curves of the device were tested.The maximum transconductance was 1.2m S,and the gate voltage at the maximum transconductance was 1.4V.（2）The FOECT glucose sensor was fabricated and the sensor performance was tested.The process parameters of electrochemical deposition of platinum on the gate are studied,and the results show that the catalytic activity of the device can be greatly improved by depositing platinum on the gate and introducing nitrogen into the electroplating solution before deposition.The carbon was basically covered during deposition for 30 minutes,and the platinum-coated gate could exist stably at 0-1V voltage.The glucose test showed a good detection ability with a detection limit of 30μM and high sensitivity.The effect of PEDOT:PSS ink composition on the detection results was studied,and the results showed no significant effect.The stability test of the sensor shows that the sensor still maintains good stability and detection ability after 100 cycles of bending.（3）The research on the printing process of the ink used in the manufacture of FOECT devices by inkjet printing technology was carried out.The printing voltage pulse waveform of PEDOT:PSS and silver ink is optimized,and the stable,good and continuous ejection of the two inks is realized.The main parameters affecting the printing quality of PEDOT:PSS films were studied and optimized.The conclusions are as follows:25μm drop spacing,4%ethylene glycol volume content,and 35°C substrate temperature can form good films.The factors affecting the quality of silver thin films were studied,and the optimum droplet spacing was found to be 25-40μm through the analysis of morphology and electrical properties.（4）The FOECT device platform as an enzyme biosensor was designed and fabricated,and the factors affecting the detection of the enzyme biosensor were studied.An inkjet-printed-based device was designed and fabricated.The device response to H₂O₂ was tested to show that gate electrodeposition could improve the detection capability of the device,the detection limit was 300 n M.The detection limit of the glucose sensor fabricated by this device in this case was 10μM.The influence of device geometry on H₂O₂ detection was studied,and the results showed that increasing the gate area or decreasing the channel length could improve the device’s ability to detect H₂O₂.