The Synthesis And Luminescence Properties Of Several Functional Materials Doped With Rare Earth Ions

The essence of luminescence is the conversion of energy.Rare earth has excellent luminescence properties due to the transitions of special 4f electronic layer structure.Rare earth inorganic luminescent materials are widely used in photoelectric switching,lighting,display devices,biological imaging?tag?,and some other fields owing to their outstanding performances,such as excellent luminescence properties,high energy conversion efficiency,strong light absorption,high monochromaticity,long lifetimes and good chemical?thermal?stabilization etc,therefore,it become a hot research topic in recent years.In general,the crystal phase,dimensionality and morphology have a great impact on its physical and chemical properties,so,to explore the nano/microstructures with superior dispersion,high purity,controllable morphology and uniform size distribution have a great significance on developing new application fields of the photolectric materials and designing novel materials in accordance with our wishes.Among various preparation methods,hydrothermal method is of particular attractive method for preparing controllable synthesis of micro/nano inorganic luminescent materials,exploring the growth mechanism of the microstructure and studying the effect of the microstructure on the luminescence properties.It has a lot of advantages such as mild conditions,stable system,low temperature,good crystallinity and environmentally-friendly.The main contents of this paper are as follows:?1?Hydrothermal method was utilized to prepare Sc₂Mo₃O₁₂ ? CaF2?Sr2ScF7 micro/nanocrystals with controllable morphologies,and their formation mechanisms were further put forward based on controllable synthesis conditions such as pH values,different additives,reaction time and temperature.?2?Multiple luminous colors were obtained by doping Ln³⁺ such as Ce³⁺?Tb³⁺?Eu³⁺?Dy³⁺?Yb³⁺?Er³⁺?Tm³⁺.Moreover,in Ln³⁺-doped Sc₂Mo₃O₁₂?CaF2?Sr2ScF7 phosphors,the excellent up/down conversion luminescence properties were revealed and the influences of doped Ln³⁺ ions on matrix materials' phases and morphologies were investigated.?3?To study the luminescence mechanism more deeply,we have mainly discussed the energy transfer process and mechanism.The energy transfer from MoO42-to Tb³⁺(Dy³⁺)to Eu³⁺ has took place in Sc₂Mo₃O₁₂ crystal,which results in tunable emission colors from green?yellow?to red by adjustment of the ratio of Eu³⁺ to Tb³⁺(Dy³⁺);The energy transfer of Ce³⁺?Tb³⁺?Eu³⁺ through nonradiative process has been investigated inCaF2,which lead to the efficient color-tunable emission from blue to green to red;the ideal white UC photoluminescence in the Sr2ScF7 nanocrystals with chromaticity coordinates of?0.320,0.330?is firstly obtained by adjusting the ratio of Yb³⁺/Er³⁺/Tm³⁺,respectively.These phosphors have good dispersion,integrity crystal structure,high crystallinity and good luminescent properties,which may have potential applications in many field.Meanwhile,it provides a new way for preparing rare earth inorganic luminescent materials,regulating the micro/nanostructure of luminescent materials and exploring its formation mechanism and luminescence mechanism.