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Research On 1550nm Infrared Light Triggered Up-conversion Luminescence Materials And Their Luminescence Manipulation

Posted on:2021-03-14Degree:MasterType:Thesis
Country:ChinaCandidate:W T HuFull Text:PDF
GTID:2381330611456945Subject:Condensed matter physics
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Rare earth ions doped up-conversion luminescent?UCL?material complies with the anti-Stokes law,which convert two or more low-energy near-infrared?NIR?photons into a high-energy visible photon through multi-photon process.The materials have potential applications in non-contact temperature sensing,anti-counterfeiting technology,solid-state lasers and photodynamic therapy,due to their advantages in optical properties.At present,the research on UCL materials is mainly focused on the materials excited by 980 nm and808 nm.Compared with the traditional 980 nm and 808 nm excitation source,1550 nm laser have many advantages such as eye-safety and low cost,etc.,so the up-conversion materials under 1550 nm excitation has more advantages in optical anti-counterfeiting applications.Secondly,the 1550 nm excitation light has deeper tissue imaging depth because its lie in the second near-infrared biological window,which is suitable for application in biological filed as an UC nanoprobe.More importantly,1550 nm photon can be absorbed directly by Er3+ absorb its excited photons,replace the energy transfer of Yb3+to achieve excellent luminescence performance.Up to now,there are many studies on Er3+doped and Er3+/Yb3+co-doped UCL materials with green color UC emissions under 1550 nm excitation,while there are relatively few red UC emissions.Furthermore,if multi-color fluorescent emission can be adjusted by changing the type of doped ions in the host material under 1550 nm excitation,which will be beneficial to the application of materials in the fields of color display,multiple anti-counterfeiting and multi-color fluorescent labeling.Therefore,this thesis aims to obtain multicolor luminescence of UC materials.1550 nm laser was adopted to excitation source,using Er3+ion as activators for single-doped samples,and double perovskite tungstate and low phonon energy of fluoride were selected as UC host material,and high-temperature solid-phase method and hydrothermal methods were used to synthesize a series of UC materials,respectively.Under 1550 nm excitation,the luminescent properties and luminescent mechanism of the samples were studied in detail by optimizing the synthesis conditions,changing the doping contents and type of rare earth ions,and the application of materials in the fields of temperature sensing and optical anti-counterfeiting were shown.This thesis includes the following three parts:1. A series of UC materials Na La Mg WO6: Er3+were successfully prepared using high temperature solid-state method.The UCL performances of the samples were optimized by changing the doping contents of Er3+,and the optimal doping contents is 30 mol%.The emission spectra of the sample in the temperature range of 280-490 K was investigated. level and the number of particles between them follows the property of the Boltzmann distribution.The temperature sensing performance of Na La Mg WO6:Er3+was investigated by fluorescence intensity ratio technique under the 1550 nm laser irradiation,and the value of optical absolute sensitivity is 0.0059 K-1.2. The UCL properties of rare earth doped Li YMg WO6 host under 1550 nm excitation were investigated for the first time. Li YMg WO6:Er3+and Li YMg WO6:Er3+,Ho3+phosphor with yellow-green and pure red emission were synthesized,respectively.The value of R/G ratio transfer process between Er3+and Ho3+and the UC mechanism were investigated based on the dependence of the emission intensities on the pump current and the fluorescence lifetime of samples.Finally,the fluorescent inks were synthesized to demonstrate the anti-counterfeiting application.3. Hexagonal Na YF4:Er3+microrods were synthesized by hydrothermal procedure.Under1550 nm excitation,the emission color output of Na YF4:Er3+was adjusted from yellow-green to pure red by introducing Ho3+/Tm3+ions.XRD analysis confirms that the lattice structure of the host material is not influenced by doping Er3+,Ho3+and Tm3+ions.The emission spectra and fluorescence lifetime clearly confirm the energy transfer from Er3+to pure red-light emission of the samples.
Keywords/Search Tags:up-conversion, rare earth ions, 1550nm, anti-counterfeiting
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