Plasmon Effect On The Structure And Luminescence Regulation Of Rod-shaped Micro-nano Rare Earth Doped Particle

Rare-earth（RE）doped luminescence materials have attracted much attention due to their unique properties of narrow emission bands,multiplexed lifetimes,multiple fluorescence colours and sensitive response to environmental temperature.This unique ability of RE-based materials have wide range of applications in bioimaging,3D multicolour display,optical device,fluorescence microscopy,anti-counterfeiting and nanothermometry.The ultimate frontier of rare earth doped luminescence materials is to realize the control of structure and luminescence characteristics with atomic-scale accuracy,and extend the range of applications in micro-nanodevices.At present,the methods on the structure and luminescence regulation of RE-doped micro-nanomaterials are mainly focused on the traditional chemical methods,such as changing chemical compositions,crystal structure and morphology,and so on.Therefore,it is important to develop some new methods to realize the control of structure and luminescence characteristics of RE-doped micro-nanomaterials,and to develop the application in various fields.With rapid development of nano-science and technology,precise temperature control at the micro/nanoscale has become a significant challenge in nanotechnology across physics,chemistry,and biology.Plasmonic metal nanostructures,which support localized surface plasmons,can be designed to act as effective light-controllable heat sources providing fast heating rates.Therefore,it is important to precisely control heating,and detect temperature of plasmonic nanostructures.Based on the plasmonic effect of metal nanostructures and the fluorescence emission of RE-doped luminescent materials,the current work focus on the study of temperature distribution characteristics of metal nanoparticles and the influence of the structure on luminescence properties of RE-doped luminescence particle through spectroscopic observation.The main contents and results are summarized as follows:1.Based on the efficient photothermal conversion of metal nanostructures under laser illumination,an optical heating system containing silver nano-islands（Ag NIs）is designed to enable heat generation at the micro/nanometer scale in a short time.The rare earth doped Y₂O₃:Er³⁺/Yb³⁺microparticle with good chemical and thermal stability is used for temperature detection.The heat generation by Ag NIs exposed to near-IR laser light,and the temperature distribution.are detected in situ via fluorescence intensity ratio（FIR）technique.It was found that the temperature of the system can be controlled by changing the excitation power.When the irradiation laser power increases from 5 to 60m W,the temperature increases monotonically from 418 to 1458 K.In addition,taking the advantage of the optical heater can provide controllable local temperature with different illumination position and power,we obtained red to green emission colour in the microparticle.2.The controllable local temperature characteristics generated by the plasmon metal nanostructures under laser illumination are used to in situ regulate the composition and structure of Na YF₄:Er³⁺/Yb³⁺particles.Crystal structure transformation from Na YF₄ to YOF and Y₂O₃is realized by changing the internal and external local temperature of micro-nano luminescent particles,and further investigate the luminescence properties of Er³⁺/Yb³⁺in related host matrix materials is carried out too.It was found that the brigth tunable colour emission from red to green can be obtained by controlling the plasmon thermal effect.3.An easy and rapid in situ method is proposed to achieve RE doped heterojunction structure growth with high spatial resolution,which is based on the localized temperature gradients produced by plasmonic heating.The fluorescence spectra of trivalent rare earth ions are selected as as a probe for local crystal structure detection.It was found that the atomic scale control of the particle structure and luminescence characteristics was achieved through precise control of irradiation position,power density and irradiation time.At the same time,we demonstrate the unique properties of adjustable upconvertion emission and selective activation the single heterojunction microrod.