| Flexible intelligent optoelectronic devices have great application potential in many technological fields such as future display,artificial intelligence and biomedicine.Recently,the relative lag of theoretical design research and experimental preparation technology of flexible intelligent optoelectronic devices with excellent performance,portable,and easy integration has gradually become a bottleneck hindering progress in related technical fields.This article focuses on the research of electronically controlled optical properties of smart materials,and then integrates them with sub-wavelength structures to prepare related devices through theoretical design,simulation and micro-nano processing.It further studies the regulation mechanism and performance characteristics of the prepared flexible intelligent optoelectronic devices.The innovative results and specific research are as follows:(1)Poly(3,4-ethylenedioxythiophene)polystyrene sulfonate(PEDOT:PSS)is an organic conductive polymer with excellent electrochromic properties.Here,the PEDOT:PSS thin films were uniformly and densely prepared on the platinum(Pt)electrode by spin coating.Using chronoamperometry,a well defined reduced state of the PEDOT:PSS films with different operating voltage was set between 0%and 100%.And the refractive index and extinction coefficient of these films depend on different reaction states were obtained by variable angle spectroscopic ellipsometry measurement in the visible spectrum(400-800 nm).It is demonstrated that in the entire visible spectrum,both the refractive index and extinction coefficient increases with the increasing of the reduction reaction degree.More importantly,these significant changes in optical characteristics are completely reversible through electrical control.This excellent electrical regulation characteristic provides a broad opportunity to control the optical properties of PEDOT:PSS films in a well-defined manner through electrochemical techniques,and has great application potential in the fields of amplitude modulators,photoelectric switches and dynamic color display.(2)We demonstrated an electrically-controlled tunable matelens(TML)working in the visible spectrum by combining both electrochromic material(ECM)and metalens on flexible substrate.The ECM is formed by combining the PEDOT:PSS,ion-gel electrolyte and transparent electrode,and the metalens is composed of gold nanorods unit cells.Firstly,we employed the finite-difference time-domain method to simulate the transmission responses of the multilayer structure with different reaction states of PEDOT:PSS film.It is shown that the reaction state and the optical parameters of the attached PEDOT:PSS films can be controlled with different bias voltage.Secondly,the effects of reaction state of PEDOT:PSS on the focal performance of the TML was experimentally studied in detail.Finally,the modulation depth,switching speed and power consumption of the device were also investigated as the change of PEDOT:PSS reaction state.Our results clearly show that this TML can effectively focus circularly polarized light in visible spectrum,and the power of focused light can be dynamically controlled by applied different operating voltages while the focal length and the focal spot size remains unchanged.It is important to note that high power modulation depth(? 80%)of the TML can be achieved at relatively small applied voltages below 2.5 V.Moreover,we further demonstrated the low APC(? 2.1 mW)and fast switching speed(? 1.26 s)of the TML.This highly integrated TML may enable new applications in optical communications,optical displays,optical imaging and lithography systems.(3)We combined ECM with all-dielectric metasurfaces on flexible substrate,and demonstrated a novel dynamic color display technology.It is formed by integrating the PEDOT:PSS,ion-gel electrolyte and transparent electrode with the patterned metasurfaces formed of indium-tin-oxide(ITO)waveguide grating arrays.Utilizing the electrically regulation property of only one kind of ECM,a flexible reflective full-colour switching with as high contrast as 90%and low-power-consume being 17 mW was obtained.Furthermore,we demonstrated that by dividing the patterned ITO electrode,electrochromic polymer and ion-gel electrolyte,it is possible to get an animation display system that capable of producing the colour graphics.It is particularly emphasized that the use of ion-gel electrolyte allows the device to be in a non-liquid state,which greatly improves the practical application.Our design is a promising approach to realize the dynamic switchable display systems.(4)A high-efficiency,broad-bandwidth reflective beam splitter based on flexible substrate and all-dielectric metasurface for visible light was proposed and theoretically designed.This all-dielectric layer consists of TiO2 nano-cylinders array and a layer by layer high efficiency reflector separated by the SiO2 spacer.Using the finite-difference-time-domain simulations,the beam splitting designed here exhibited an excellent abnormal reflection ability and efficiency of higher than 90%over a 70 nm bandwidth(490-560 nm),especially,at a few wavelengths,conversion efficiency close to or even above 94%can be already realized.At the same time,a high-efficiency transmissive all-dielectric beam splitter based on flexible substrate and TiO2 nanocylinder array was also proposed,which works in the visible light band(532 nm).The numerical simulation results showed that the beam splitter has excellent abnormal transmission ability,and the energy conversion efficiency as high as 90%.We also proposed and theoretically designed a transmissive all-dielectric tunable beam splitter based on a flexible substrate,PEDOT:PSS and TiO2 nanocylinder array.It works in the visible light band(532 nm).The numerical simulation results show that the voltage can be used to dynamically adjust the energy conversion efficiency of the beam splitter while maintaining the beam splitting effect,and the modulation depth of the energy conversion efficiency can reach 78%. |
PDF Full Text Request