Construction And Applications Of PEDOTs-Based Conducting Polymer Hydrogel Electrochromic Devices

As an energy-saving display technology,electrochromism refers to the double injection,extraction or redox reaction of electrons and ions under the action of a weak electric field,so that the color can undergo reversible and continuous changes.It has been used in smart windows,electronic displays,smartphones and other fields have achieved industrial applications.With the rapid development of flexible electronics,wearable electronics,and smart displays,as well as the general trend of device flexibility,stretchability,multi-functionality,integration,and miniaturization,both basic research and the industry are interested in electro-discoloration presents new requirements for high flexibility,fast response,long-term stability,and versatility.Therefore,how to develop high-performance flexible electrochromic materials and their low-cost,large-scale processing integration technology to construct multifunctional flexible devices has become a key challenge in the field of electrochromism.The rational design of high-performance flexible electrochromic materials and the development of low-cost processing technologies are the key factors restricting the development of flexible electrochromic materials.Existing electrochromic materials,such as transition metal oxides,conductive polymers,Mxene,COF,MOF,etc.,still have the limitations of slow response speed,low coloring efficiency,poor stability and poor softness,stretchability and other mechanical properties In addition,most rely on high-cost and complex processing integration technologies such as spin coating,electrochemical polymerization,and roll-to-roll,which limits its practical application research and development.In recent years,with the rapid development of flexible electronics,flexible electrochromism has attracted much attention,and the demand for multifunctional devices,the application and development of flexible optoelectronic displays are still severe challenges.Based on the above problems,this thesis takes conductive polymer hydrogel as the core,and designs and constructs a microphase-separated conductive polymer hydrogel with fast response and long-term stability,and a double-network conductive polymer with excellent long-term stability through the regulation of crystal phase structure.Biohydrogels and highly stretchable and fast-responsive bicontinuous network conductive polymer hydrogels.Systematically study its electrical,electrochemical,electrochromic,and mechanical properties,and reveal the material structure-property correlation rules;develop screen-printable inks with controllable rheological properties through strategies such as concentration control and aggregation state control And 3D printable inks,realize the programmable patterning and large-scale rapid manufacturing of such hydrogels;further construct flexible and stretchable electrochromic devices of new conductive polymer hydrogels.Evaluate its electrical,electrochemical,electrochromic,mechanical,stability and other properties,and discuss its application prospects in flexible electronic fields such as flexible array electronic displays,deformable displays,smart windows,and wearable electronic devices;The research and large-scale application of flexible electrochromic materials provide certain theoretical guidance and technical support.The specific research content and results are as follows:1.Proved the feasibility of PEDOT:PSS conductive polymer hydrogel as a flexible electrochromic material,and found properties such as fast response,high coloring efficiency and long-term stability;further developed large-area screen printing technology,low-cost,large-scale fabrication of high-performance flexible patterned electrochromic devices has been realized at first.PEDOT:PSS was dried and annealed,and ferric chloride（Fe Cl₃）was post-treated to form a phase-separated network structure,and complexed with PSS to realize supramolecular self-assembly,and a PEDOT:PSS conductive polymer hydrogel with high ion transport and high electron conductivity was obtained A new type of material that causes color change.The system characterized and tested its surface morphology,electrochromic performance,electrochemical,electrical performance and long-term stability,and explored the structure-activity relationship between the structure and performance of the material.It was found that PEDOT:PSS conductive polymer hydrogel electrochromic material achieved fast response（coloring time:0.47 s;bleaching time:0.39 s,which is the latest record in the field of PEDOT:PSS electrochromic）,high coloring efficiency（730.8 cm²/C,5 times that of traditional PEDOT:PSS）.At the same time,the phase structure regulation improves the matching degree of ion-electron migration efficiency,and improves the cycle performance to more than 10,000 times with an attenuation of<5.3%.Based on this,by preparing PEDOT:PSS screen-printable ink,a three-layer structure conductive polymer hydrogel flexible patterned electrochromic device was assembled,which demonstrated excellent mechanical stability（10000 bending cycles at 7 mm curvature radius The contrast ratio remained at 90.3%after cycling）.And explore the application prospects of conductive polymer hydrogel electrochromic devices in flexible array displays,digital displays,wearable electronic devices,and smart windows.2.Established a PEDOT:PSS-like hydrogel crystal phase network structure optimization design method,constructed a PEDOT:PSS-PVA double network hydrogel with excellent electrochromic properties and mechanical properties;then developed its 3D printing technology to realize Rapid fabrication of high-performance flexible patterned electrochromic devices.The mechanical network PVA was introduced into the PEDOT:PSS network to form a second mechanical network to construct a PEDOT:PSS-PVA hydrogel with a double network structure;ferric chloride（Fe Cl₃）was post-treated to complex PSS to achieve supramolecular self-assembly,and obtained high PEDOT:PSS-PVA hydrogel electrochromic new material with ion transport and high electron conductivity,achieving high optical contrast（54.1%）,fast response（coloring time:0.74 s;bleaching time:0.37 s）,high coloring efficiency（213.5 cm²/C）.At the same time,the regulation of the phase structure and the existence of the macroporous structure improve the ion diffusion efficiency,improve the cycle performance to more than 20,000 times and attenuate<2.2%.It is the first time to prepare 3D printable electrochromic ink and assemble a three-layer structure flexible patterned electrochromic device,showing excellent kinetic stability（optical contrast decreased by 6.7%after 15,000 electrochemical cycles）and mechanical stability（contrast decreased by 13.9%after 10,000 bending cycles at a curvature radius of 1.2 cm）.The application of electrochromic two-dimensional code display based on PEDOT:PSS-PVA hydrogel was further demonstrated,showing its great application potential in digital encryption/decryption,Internet of Things and other fields.3.Intrinsically stretchable PEDOT:PSS-PU hydrogel electrochromic material was developed for the first time,which realized the simultaneous improvement of the mechanical properties and electrochromic properties of the material,and further assembled the all-hydrogel intrinsically stretchable electrochromic devices.The solvent effect produces nanoscale microphase separation between the two continuous phases of PEDOT:PSS and PU.The electrochromic network and the mechanically stretched network can independently exert their greatest advantages without affecting each other.The intrinsically stretchable PEDOT:PSS-PU is prepared for the first time conductive polymer hydrogel electrochromic new material realizes simultaneous improvement of electrochromic and mechanical properties.PEDOT:PSS-PU conductive polymer hydrogel electrochromic material achieves high optical contrast（68.1%）,fast response（coloring time:0.51 s;fade time:0.39 s）,high coloring efficiency（341.3 cm²/C）and high stretch（350%）.Simultaneous phase structure regulation improves the conductivity（14.34 S/cm）,improves the cycle performance to more than 30,000 cycles and attenuates<7.7%)Based on bicontinuous PEDOT:PSS-PU conductive polymer hydrogel and 3D printing technology,an all-hydrogel stretchable electrochromic device was further assembled for human wearable electronic devices.This research provides a new design idea for the design of wearable electrochromic devices and intrinsically stretchable electrochromic devices.We firmly believe that PEDOT:PSS conductive polymer hydrogels have great application prospects in the field of flexible and stretchable electrochromics.At the same time,the introduction of 3D printing technology provides processing technology support for the application and promotion of stretchable electrochromic in patterned wearable displays.This paper focuses on key scientific issues such as the development of high-performance flexible electrochromic materials,the lack of advanced processing integration technology,and the construction of multi-functional devices.Systematic and in-depth research has been carried out in application and other aspects,and systematic theoretical and technical achievements have been obtained.Using PEDOT:PSS hydrogel as the core material,a multi-scale optimization design method for the electrochromic-electrical-mechanical phase network structure was constructed through crystal phase engineering regulation,and three high-performance PEDOT:PSS hydrogel electrophoresis were designed and developed.As a new material for chromism,the developed hydrogel has excellent electrochromic,electrochemical,electrical and mechanical properties,opened up the electrochromic field of conductive polymer hydrogel,and developed a high-performance intrinsically stretchable Chromogenic materials;advanced processing technologies such as screen printing and3D printing have been established,and low-cost and large-scale processing and manufacturing of flexible electrochromic devices and intrinsically stretchable electrochromic devices have been realized;further explorations have been made in digital display,The application potential of flexible optoelectronic displays such as wearable electronics,smart windows,and information encryption.This study not only broadens the research scope of electrochromic materials,but also integrates research in multiple fields,which lays a solid foundation for the development of electrochromic fields.