Research On The Application Of γ-Fe₂O₃/Graphene Magnetic Ink In Flexible Electronic Devices

At present,the application demand of flexible electronic devices forces people to explore new solutions to meet the demand for new functional devices,and the birth of functional ink has realized the application demand for all kinds of different electronic devices.Although many types of functional ink have been prepared,magnetic ink used in electronic devices have rarely been reported.However,in order to produce high quality magnetic ink,the agglomeration of magnetic nanoparticles in solvents and poor hydrophilicity must be solved.As a super paramagnetic N-type semiconductor material,γ-Fe₂O₃has good magnetic properties and variable valence,but it also has some limitations,such as poor hydrophilicity and dispersivity.As a two-dimensional material,graphene has good electrical conductivity and hydrophilicity.By compoundingγ-Fe₂O₃ and graphene,a magnetic ink with better hydrophilicity is prepared,and the required flexible electronic device is prepared.In summary,strengthening the study on magnetic ink is not only the basis for accelerating the development of flexible electronic technology,but also a key step towards low-cost,fully printed,and controllable electronic devices.In this paper,γ-Fe₂O₃/graphene magnetic ink as the entry point,focusing on its application in flexible electronic devices.The main research contents and results are as follows:1.Preparation and characterization of magnetic ink.In this study,oleic acid was used to realize the surface functionalization,so that the functionalizedγ-Fe₂O₃ had better dispersion in the solvent.At the same time,the prepared GO suspension was added to produce a functional ink that can be used for printing,with good dispersion and excellent magnetic properties.In addition,due to the compound of GO,the hydrophilicity of ink was greatly improved,which further has promoted the flatness of the printing surface,reduced the internal defects or gullies produced in the printing process,and laid a solid foundation for the preparation of flexible electronic devices.2.Research on flexible memristor based onγ-Fe₂O₃/GO.In this study,the flexible memristor with the structure of Ag/γ-Fe₂O₃-GO/Ag was designed and fabricated on a flexible substrate by means of full-printing,which changed the traditional rigid memristor based on the silicon substrate Metal-Oxide-Semiconductor Field-Effect Transistor（MOS）structure.Compared with the pureγ-Fe₂O₃ flexible memristor,theγ-Fe₂O₃/GO flexible memristor has more stable and gradual memristor characteristics.This has proved that the device has good memory properties and can simulate the excitatory and inhibitory behavior of biological synapses,which provides a new idea for the application of printable functional ink in memory elements.3.Research onγ-Fe₂O₃/rGO acetone sensor.This study has usedγ-Fe₂O₃/GO composite ink,through 200℃,3 h thermal reduction,prepared on the printed silver fork electrodeγ-Fe₂O₃/r GO acetone sensor,and further has explored the temperature and different reduced graphene oxide（r GO）content on the acetone sensor gas sensitive characteristics.The results have showed that the prepared 1%r GO/γ-Fe₂O₃acetone sensor exhibits a response value of 2.6 at 200℃to acetone vapor of 10 ppm,and its response/recovery time was 7/227 s.In addition,adding magnetic fields in different directions during the testing process will have different effects on the acetone sensor.When the direction of the attached magnetic field was horizontal,the device sensitivity has been increased to about 3.8,which was 1.5 times of that without the attached magnetic field.At the same time,the preparedγ-Fe₂O₃/r GO acetone sensor has achieved high selectivity for acetone at low temperature.In conclusion,the phenomenon of improving the gas sensitivity of acetone sensor based on the addition of magnetic field provides a reference for breaking the bottleneck of wet chemistry method to improve the acetone sensor.To sum up,we formulated a magnetic ink,and applied it to flexible memristor and acetone sensor,both show good characteristics,which provides an experimental basis for exploring the application of magnetic ink in flexible electronic devices.