Synthesis Of Mesoporous Luminescent Materials And Their Applications In Transition Metal Ions Detection

Inorganic luminescent materials have more and more applications in the fields of illumination,bio-imaging,fluorescent marking,optoelectronic devices,displays,etc.due to their wide variety,unique illumination,environmental friendliness,and good biocompatibility.In this work,well-dispersed luminescent calcium hydroxyphosphate and strontium hydroxyphosphate nanorods and rare earth ions doped calcium fluoride hollow spheres were synthesized by hydrothermal method.The phase,composition,morphology,luminescence detection,adsorption and desorption performance for transition metal ions were also investigated in detail.The uniform and well-dispersed rod-like calcium hydroxyphosphate and strontium hydroxyphosphate samples have been prepared by a mild and simple hydrothermal method.It can be seen from the SEM,TEM,and nitrogen adsorption/desorption result that the samples exhibit regular rod-like morphology and mesoporous structure.Under ultraviolet excitation,a strong blue light emission peak can be found at 436 nm.The luminescence mechanism is initially determined to be related to carbon dioxide radicals in the sample lattice,which is a typical defect luminescent material.Due to their high specific surface area,unique fluorescence properties,and mesoporous properties of the samples,We can detect different metal ions(CrO₄^2-,Fe³⁺,Cd²⁺,Cu²⁺)by using the change of the fluorescence intensity of the material after adsorbing metal ions.we have tried to select CrO₄^2-for desorption studies for the detection of toxic heavy metal ions.The results show that the sample not only has a certain ability to detect and adsorb metal ions,but also has some hope in the recyclability of the samples.The calcium fluoride nanospheres doped with Ce³⁺and Tb³⁺were prepared by hydrothermal route with sodium citrate as the additive.Ce³⁺,Tb³⁺-codoped CaF₂ hollow spheres show efficient energy transfer from Ce³⁺to Tb³⁺.Under the excitation of light,a strong green light emission can be obtained.The strong green photoluminescence can mainly attribute to the 541 nm emission of Tb³⁺,which is ⁵D₄?⁷F₅ transition of Tb³⁺.The nitrogen adsorption desorption curve indicates that the as-synthesized material is a mesoporous structure.The adsorption properties of toxic heavy metal ions on CrO₄^2-,Fe³⁺,and Cd²⁺were studied.The results show that calcium fluoride hollow spheres have good adsorption and detection capacity for all three model ions,and the as-synthesized CaF₂:Ce³⁺,Tb³⁺hollow spheres also exhibit the recycling ability.