Preparation And Up-Conversion Luminescence Properties Of Rare Earth Oxide Doped Tio₂ Based Organic-Inorganic Composite Optical Waveguide Films

Up-conversion luminescence of rare earth ions is an anti Stokes process.Rare earth up conversion luminescent materials have been widely used in laser anti-counterfeiting,bio imaging,photocatalysis,solar cells and other fields due to their advantages such as good luminescent stability,high efficiency,high temperature resistance,and not easy to occur chemical reactions.In recent years,they have received great research interest from researchers.In addition,the organic-inorganic composite materials prepared by sol-gel method have the advantages of organic materials and inorganic materials.By changing the types of organic components and inorganic components in materials and adding different functional groups in materials,functional composite materials with excellent optical properties can be prepared.Therefore,researchers have done a lot of research on materials in recent years.In this paper,neodymium oxide and erbium oxide nanocrystals were prepared by inverse microemulsion method.TiO₂ based organic-inorganic composite films were prepared by sol-gel method.The neodymium oxide and erbium oxide nanocrystals were doped into TiO₂ based organic-inorganic composite films respectively.The structure and luminescent properties of neodymium oxide and erbium oxide nanocrystals were systematically studied.The surface morphology,waveguide properties and up-conversion luminescence properties of doped neodymium oxide and doped erbium oxide composite films were studied.The specific research contents are as follows:Neodymium oxide and erbium oxide nanocrystals were prepared by inverse microemulsion method.The crystal structure,chemical composition and crystal surface morphology of neodymium oxide and erbium oxide nanocrystals were characterized by X-ray diffractometer,X-ray photoelectron spectroscopy and high resolution transmission electron microscopy.The results show that the doped neodymium oxide and doped erbium oxide nanocrystals have high purity and crystallinity.The neodymium oxide and erbium oxide nanocrystals TiO₂ based organic-inorganic composite films were prepared by sol-gel method and spin coating method.The surface morphology of the composite films was observed by scanning electron microscope,and the optical transmittance of the composite films at different heat treatment temperatures was studied.When the heat treatment temperature is below 300?,the composite films have higher optical transmittance in the UV-Vis band.Based on the prism coupling technology,the characteristics of optical waveguide,including the refractive index and thickness of the film and the optical transmission mode,are tested and analyzed.The results show that the thickness of the film is between 0.7?m and 2.0?m,and the thickness of the film decreases with the increase of heat treatment temperature.At last,the up-conversion luminescent properties of the composite films under different heat treatment temperature were studied by fluorescence spectrometer.Specifically,the up-conversion luminescent properties of the composite films doped with neodymium oxide nanocrystals were studied under the excitation of 580nm light source.There are many purple and blue luminescent peaks in the luminescent spectrum,of which the purple luminescent at 436nm is the most obvious.Under the excitation of 818 nm light source,the up conversion luminescent properties of doped erbium oxide nanocrystals composite films are tested.The green and red peaks can be seen in the luminescence spectrum.In addition,the luminous intensity of the composite film increases with the increase of heat treatment temperature,and reaches the maximum when the heat treatment temperature is200?.Finally,based on the UV photosensitive functional group added to the composite film,the composite film has the UV curing function at the same time.The microlens array structure and the strip waveguide array structure are prepared on the doped neodymium oxide and erbium oxide nanocrystals composite film by UV nano imprinting technology,respectively.The microlens diameter is about 25?m,the height is about 5?m,the width of strip waveguide is 5-20?m.This research is expected to be widely used in LED,optical amplifier,optical communication and other fields.