Photonic Crystal And Plasma Resonance Effect Enhanced Photoluminescence And Its Application Exploration

Photoluminescent material is a kind of material that's stimulated by the outside light.The excitation and emission processes include the absorption of light,energy transfer and the emission.The common luminescent materials have the three basic color energy saving lamps in the field of illumination,the safety signs of the shopping malls,and the medical X-ray image.It can be said that the photoluminescence materials have been widely involved in our lives.In addition,the researchers are interested in the application of carbon dots nanomaterials and upconversion nanomaterials which can be used in bio-imaging,high-efficient solar cell.Although the upconversion nanomaterial has the advantages of stable luminescence intensity,no chemical bleaching and long lifetime,it still requires a higher absorption efficiency and a higher photon conversion efficiency in practical application.What's more,another kind of photoluminescence materials-carbon dots materials have adjustable,stable photoluminescence properties.It has the high absorption cross section,good biocompatibility,wide and cheap preparation of materials and other series of advantages,which can be applied to the solar cells,photocatalysis device and photoelectric detection device.However,the application of this kind of carbon dots materials is that there are few methods for the preparation of rare earth materials with high and pure solid state.However,the application of this kind of materials also has a few problems to be resolved,for instance,the luminescent quantum yield except blue emission is still low.In this paper,we contribute to enhance the luminescence of the upconversion nanomaterial and carbon dots.We designed the efficient multi-layered nanostructure film of photonic crystal structure and metal nanoparticles,and explored them in the application of trademark anti-counterfeiting and fingerprint recognition:Firstly,a two-dimensional anodic alumina nano-material?2D AAO?was prepared,which is a 2D photonic crystal material.It could control the electromagnetic field with long range to avoid the fluorescence quenching in close proximity.We used a simple,direct self-assembly method to grow NaYF₄:Yb³⁺,Er³⁺nanocrystals on the glass,aluminum,AAO substrate,and successfully obtained65-fold fluorescence enhancement.In order to determine the mechanism of this enhancement,finite-different time-domain was calculated to simulate the electromagnetic field.It originated from the optical action of interference diffraction,which effectively enlarged the electromagnetic field of the two-dimensional AAO photonic crystal material.And the sample had a long range of light field.Secondly,we designed and prepared a structure which combined the photonic crystal structure framework and periodic island silver Cap composite films—PMMA PCs/Cap-ag/Ta₂O₅/NaYF₄:Yb³⁺,Er³⁺.This kind of composite structure used semiconductor oxide for isolation layer,noble metal nano structure for plasma resonance layer,photonic crystals for excitation field coupling and template layer to enhance the luminescence of rare earth doped UCNPs.This composite film can be tuned to the flexible substrate and use nano-printing technology to present the near-infrared trademark anti-counterfeiting.Thirdly,we designed a new type of structure which was carried out by photonic crystals effect of PMMA PCs for the far field and surface plasma resonance effect of Au-Ag NPs for near field to enhance the local electromagnetic field.The theoretical calculation of FDTD proved the mechanism of electromagnetic field amplification,and it successfully enhanced the fluorescence of the orange carbon dots.The preparation of composite film was applied to high resolution fingerprint recognition technology.