The Construction And Application Of Temperature Probe Based On Er/Tm Partition Doped Nanostructure

Non-contact optical temperature measurement based on rare earth luminescent materials have been widely concerned in recent years.Compared with traditional contact temperature measurement methods,this method has lower requirements on temperature measurement environment and can achieve high sensitivity and precise temperature measurement in various extreme environments.Optical temperature measurement is basically a method of temperature measurement based on the dependence between optical characteristics and temperature.Among them,the temperature measurement rooted on luminescence intensity ratio has attracted much attention due to its simple operation and high sensitivity.Generally,materials with thermally coupled energy levels are used as fluorescent probes in the luminescence intensity ratio temperature measurement method;thermally coupled energy levels refer to the energy levels where electron population meets the Boltzmann distribution,but they need to be satisfied with specific gap requirements(200 cm^-1-2000 cm^-1)while low temperature may lead to the fact that electron population no longer meets the Boltzmann distribution,thus the energy levels are decoupled.An important topic is how to accurately implement luminescence intensity ratio temperature measurement at low temperatures.The up-conversion luminescent nanomaterials doped with rare earth are very suitable to be used as temperature-sensitive probes because of their stable physicochemical properties,multi-band emission and abundant energy level structure.In this study,based on Er/Tm partition doped nanomaterials,multilayer core-shell upconversion luminescent nanomaterials were constructed to achieve efficient non-contact optical temperature measurement in the low-temperature range.Na Er F₄-based nanoparticles were prepared by solvothermal method and epitaxial growth was carried out by Ostwald curing method.The nanoparticles were coated withβ-Na YF₄to form core-shell structure,which avoided the influence of concentration quenching on up-conversion luminescence.The morphology and size of the nanoparticles were determined by characterization.The up-conversion luminescence mechanism of Na Er F₄@Na YF₄nanoparticles under near-infrared excitation was analyzed with energy level theory,and it was found that doping Ce³⁺and Tm³⁺could quench or enhance the 654 nm luminescence of Er³⁺,respectively.The dependence between material up-conversion luminescence and temperature change at cryogenic field was recorded.Effective ratiometric temperature detection in cryogenic field could be realized by using the luminescence intensity ratio of non-thermal coupling level in the system.In order to further improve the sensitivity of temperature probe,nanoparticles with multilayer shell structure Na Er F₄:RE@Na YF₄@Na Yb F₄:Tm@Na YF₄were prepared.Partition doping epitaxial growth introduced new luminescence centers to provide more luminescence peak selection.The inert shell can effectively block the energy transfer of the two layers of luminescence centers.The upconversion luminescence behavior of different luminescent layers is relatively independent.The sensitivity of temperature probe is improved by introducing a new luminescent center.Na YF₄:Yb,Er@Na YF₄@Na Yb F₄:Tm@Na YF₄,multilayer core-shell structure up-conversion nanomaterial were prepared by optimizing core doping into Yb/Er co-doping system and partition doping ratio.The materials can realize effective ratio temperature detection in cryogenic field,and the sensitivity is further improved.Based on the temperature-dependent luminescence properties,it can be applied to cryogenic field optical anti-counterfeiting.