Preparation And Study Of Flexible Inorganic Alternating Current Electroluminescent Devices With Pressure Visualization

Since the popularization and application of electroluminescence(EL),the emergence of alternating current electroluminescence(ACEL)devices has made the field of EL transition from traditional low-power lighting display to visual sensing,electronic skin and intelligent display.ACEL has many inherent advantages.For example,luminescent materials can be prepared at low cost through ink configuration;and through the intervention of an insulating layer,the electrochemical reaction between the luminescent layer and the electrode is greatly reduced,and it can still work normally in harsh environments.However,most of the current research is limited to the optimization of luminescent display,and rarely expands to the functionality and visual sensing around other structures of ACEL,which limits the multifunctional display application of ACEL.In view of the above problems,this thesis carried out the following research:(1)All-Printed Flexible Alternating Current Electroluminescent Devices based on Bottom Light-Emitting Structure(BES)Top Light-Emitting Structure(TES)and Coplanar Electrode Structure(PES)were obtained by combining different printing methods.The luminescent materials and dielectric materials were characterized by SEM,XPS,XRD.The luminescence wavelength,luminescence luminance,luminescence efficiency and color coordinates of ACEL were characterized and analyzed under different voltages and frequencies.The results show that the maximum luminance of the three ACEL structures is 170 cd/m~2,70 cd/m~2,65 cd/m~2at 180 V and 500 Hz,respectively.It was worth mentioning that the functional ink with good printability was obtained through ink configuration,and the integrated luminous packaging boxes were prepared by screen printing,inkjet printing,die cutting and indentation.(2)Hydrogel microcapsules were introduced into PES-ACEL to realize pressure visualization.The sodium alginate system was formed by the same content of poly(3,4-ethylene dioxythiophene)/polystyrene sulfonate(PEDOT:PSS),silver nanowires(Ag NWs),single-walled carbon nanotubes(SWCNTs)and deionized water respectively.Calcium alginate hydrogel of chitosan-urea resin composite wall material was prepared by sharp-hole coagulation bath method and in-situ polymerization method.Based on the controllable storage and release characteristics of microcapsules and the visual display effect of ACEL devices,a novel visual pressure interactive display electroluminescent device(VPI-ACEL)was fabricated,characterized experimentally and applied in practice.The results show that the prepared hydrogel microcapsules have the advantages of environmental protection,stability and pressure sensitivity.When the force acting on the interaction layer is greater than 1.5 N,the luminance of the device can reach 50 cd/m~2(140 V,1000 Hz),and the device has excellent interaction effect and visual feedback without color polarization.In the future,VPI-ACEL can be directly used in the field of lightweight pressure monitoring to promote the development of visual monitoring system.(3)In order to solve the problems of VPI-ACEL,such as poor sealing performance,low circulation efficiency and small pressure dynamic range,etc.We propose a multi-dimensional pressure interactive visual monitoring device(MPI-ACEL)based on ionic liquid hydrogel and PES-ACEL.With the help of water self-regeneration and high elastic circulation and temperature and humidity self-adaptation ability of hydrogel,the functions of dynamic real-time pressure visual sensing and static delay monitoring are realized.Then,the advantages of pressure sensing area and luminescent display area are discussed,and the luminescent performance and cycle life of MPI-ACEL in three dimensions of pressure,temperature and humidity are studied,which verifies the possibility of multifunctional application of MPI-ACEL.Then,the advantages of pressure sensing area and luminescent display area are discussed,and the luminescent performance and cycle life of MPI-ACEL in three dimensions of pressure,temperature and humidity are studied,which verifies the possibility of multifunctional application of MPI-ACEL.It provides a new flexible and effective scheme for adaptive directional indication and multi-dimensional remote monitoring of visual pressure sensing environment.