Study On Preparation Of Copper Complex Ink And Its Sintering Performance At Low Temperature

Copper MOD ink can perfectly avoid the problem of copper oxidation,and as a result,it has been playing an increasingly important role in flexible and wearable electronic products in recent years,speeding up the transition of innovative electronic products from the laboratory to industry.However,the traditional hot sintering process of copper MOD ink requires a temperature of more than 140 ℃,which greatly limits the application of low-cost flexible substrate in this field.The plasma sintering process can solve this problem to a large extent by allowing the copper MOD ink to sinter at low temperatures.However,the use of plasma sintering to obtain a copper structure still faces many challenges,such as the formulation of the ink,the plasma sintering process,and the relationship between the properties and microstructure of the resulting copper structure,which requires systematic research.The preparation of high-performance copper films with different thicknesses,especially ultra-thin copper films,using plasma technology needs further exploration.In addition,the anti-aging stability,flexibility,reliability,and adhesion between the copper structure and substrate prepared by the plasma process need to be improved.Furthermore,the mechanism of plasma-induced sintering of copper MOD ink remains unclear.Therefore,this dissertation systematically studied the plasma sintering process and ink formulation of copper MOD ink,clarified the possible mechanisms of sintering copper MOD ink by the plasma process,optimized the surface structure of the copper film,and explored more possibilities for preparing copper films of different thicknesses with high conductivity,stability,flexibility,and strong adhesion at low temperatures using the plasma process.The possibility of integrating this process with green manufacturing applications,such as roll-to-roll printing and direct pen writing,was also explored,and the application of the prepared copper film in flexible electronic devices was developed.The main research contents are as follows:(1)The study focuses on the use of plasma sintering copper MOD ink at low temperatures to directly prepare high-performance conductive copper structures on thermally sensitive flexible substrates.This involves clarifying the influence of the preheating process(temperature,time),plasma sintering process(power,time,gas flow,gas type)on the electrical properties and microstructure of printed copper structures,and understanding the underlying principles.The study also proposes a potential mechanism for plasma sintering.(2)The research systematically explores the relative content of two kinds of amine and solvent content on the preparation of copper film microstructure,electrical properties and ink stability.The interaction mechanism between the plasma process and ink formula is also studied through experiments and analysis,especially the effect of the sintering process on ink with different solvent content.Finally,high-performance copper films of different thicknesses(40～120 nm)are obtained.(3)The study systematically explores and evaluates the bending stability of copper film under different bending radii,the folding stability when fully folded,the adhesion stability between the copper film and substrate,and the anti-aging stability of the copper film under high temperature and high humidity.The results are interpreted,and the high temperature stability of copper film is optimized by introducing the nickel element into the ink.(4)The study combines the plasma process with roll-to-roll printing and direct pen writing to produce complex copper patterns.Finally,the prepared copper film is applied to a capacitance sensor of which the responsiveness,stability,and sensitivity of the capacitance sensor are evaluated.This provides a new route for the rapid preparation of large-area,low-cost,or complex printed flexible electronic devices.