Orange-Red Luminescent Materials Doped With Samarium And Their Biological Applications

Rare earth elements have rich optical,electrical and magnetic properties due to their unique 4f sublayer electronic structure,large atomic magnetic moment,strong spin-orbit coupling,variable coordination number and crystal structure.Compared with other spectroscopy techniques,fluorescence technology have the advantages of high resolution,sensitivity and simple instrument.It has been widely used in the fields of environment,biochemistry,and medicine.The research and development of red phosphor which can be effectively excited by near UV light,with high luminous efficiency and more environmental protection is the current bottleneck in this field.Therefore,it is very important to find a synthesis method of red phosphor which can be excited by the blue light and near UV light.Among many rare earth ions,Eu3+has been more studied,but Sm3+with red light emission characteristics has not been much studied.Rare-earth doped nano-luminescent materials have potential applications in biomarkers and drug carriers.At present,the main factors limiting the application of these materials in biomedical field are hydrophilicity,biocompatibility and molecular mechanism.For this reason,this paper will be studied from the following aspects.(1)The precursor was synthesized by sol-gel method using Sm3+as activator,SrMoO4 as substrate,citric acid as complexing agent and glycol as auxiliary complexing agent.Firstly,the optimum doping amount and quenching mechanism of Sm3+were studied,and then the influence of the calcination temperature(700,800,900,1000,1100 and 1100?)was studied.Finally,the effects of charge compensation agent(Na+,Li+,K+)on the structure,morphology and luminescent properties of red phosphor were studied.(2)The red phosphor was prepared by hydrothermal method with Sm3+ as activator and NaLa(WO4)2 as matrix.First,the pH value,the optimum doping amount of Sm3+,the quenching mechanism of Sm3+concentration and the formation mechanism of Sm3+morphology were studied.Then,in order to further improve the luminescent properties of NaLa(WO4)2:Sm3+phosphor,the effects of Ce3+and Eu3+ co-doping on the structure,morphology and luminescent properties of NaLa(WO4)2:Sm3+phosphors were studied in detail.The mechanism of energy transfer between Ce3+and Sm3+and between Sm3+and Eu3+was mainly analyzed.(3)A series of YPO4:Sm3+phosphors were prepared by hydrothermal method with Sm3+as activator and YPO4 as matrix.Firstly,the optimal synthesis process was optimized by orthogonal experiment.The influence of acidity and basicity on the morphology formation mechanism and luminescent properties of red phosphor was mainly studied.Secondly,the morphology formation mechanism and fluorescence temperature characteristics of the spherical nano-phosphor YPO4:Sm3+were studied.The spherical nano-phosphor with the diameter of 50-90nm was obtained by optimizing the comprehensive properties.(4)The surface of spherical nano-phosphor YPO4:Sm3+was coated and modified by chitosan and TEOS,and the nano-phosphor YPO4:Sm3+@CS and YPO4:Sm3+@SiO2 with the hydrophilic core-shell structure were obtained.Its goal is to make the spherical nano-phosphor YPO4:Sm3+hydrophilic and enhance the affinity of the luminescent body-surface layer-organism.(5)The adsorption process of BSA by YPO4:Sm3+,YPO4:Sm3+@CS and YPO4:Sm3+@SiO2 at room temperature was studied using the adsorption principle.Meanwhile,the quantitative calibration of BSA by YPO4:Sm3+@CS and YPO4:Sm3+@SiO2 was also studied.(6)Bovine serum albumin(BSA)was selected as the protein template to study the interaction between the core-shell spherical nano-phosphor YPO4:Sm3+@CS and BSA,and its influence on the structure and properties of BSA using the molecular interaction model,protein structure principle and molecular docking theory.