Research On Flexible And Stretchable Au/Ferroelectric Thin Film/Au Prototype Devices

Recently,traditional rigid electronic devices have been seriously affected by the rapid development of flexible wearable electronic devices,electronic skin and etc.As a result,how to make these rigid devices flexible and stretchable has become an urgent problem to be solved.Among them,ferroelectric devices have attracted widespread attention due to their excellent ferroelectric,piezoelectric and pyroelectric properties,which are more practical and valuable to expand their applications in the flexible and stretchable field.However,both organic ferroelectric materials with natural flexibility and traditional rigid inorganic ferroelectric materials have encountered many bottlenecks in the process of achieving flexibility and stretchability,and there are few reports on ferroelectric properties under complex deformation conditions so far.We select P（VDF-Tr FE）organic ferroelectric polymer and Pb Zr_0.52Ti_0.48O₃ inorganic ferroelectric material as the research objects,and prepare their thin film prototype devices by spin coating method and pulsed laser deposition method respectively.Furthermore,the changes of ferroelectric properties of these devices in flat,bending,buckling and re-stretching states are investigated.The specific progress is as follows:Firstly,a flexible and stretchable PDMS/Au/P（VDF-Tr FE）/Au organic ferroelectric thin film prototype device is successfully fabricated,using polydimethylsiloxane（PDMS）as a direct flexible and stretchable substrate.Among them,the PDMS/Au composite thin film can withstand 3%bending strain,the recovery and re-stretching of 40%unidirectional pre-stretch strain or 25%bidirectional pre-stretch strain.In addition,the remnant polarization of the prototype device at 3%bending strain can still be maintained more than 86%compared with the flat state,and it can be maintained more than 85%compared with the flat state after the recovery and re-stretching of 30%unidirectional pre-stretch strain or 10%bidirectional pre-stretch strain.Secondly,based on two different thin film growth and transfer schemes,we achieve the successful transfer of the thin film from a rigid silicon wafer substrate to a flexible PDMS substrate,resulting in the successful preparation of flexible and stretchable PDMS/gold foil/Pb Zr_0.52Ti_0.48O₃/Au inorganic ferroelectric thin film prototype device.Different from the former,gold foil provides the possibility for the growth and transfer of high-temperature Pb Zr_0.52Ti_0.48O₃ films,and through the same bending and strain recovery process,PDMS/gold foil composite thin film can withstand 4%bending strain,the recovery and re-stretching of 40%unidirectional pre-stretch strain or 25%bidirectional pre-stretch strain.In addition,the remnant polarization of the prototype devices obtained by two different schemes at 4%bending strain can still be maintained more than 70%compared with the flat state,and it can be maintained more than 80%compared with the flat state after the recovery and re-stretching of 30%unidirectional pre-stretch strain or 10%bidirectional pre-stretch strain.In conclusion,based on different film preparation and transfer processes,this thesis has achieved breakthroughs in flexible and stretchable electronic devices of organic and inorganic ferroelectric thin films,and provided a feasible idea for the realization of flexible and stretchable ferroelectric devices.