【作者】 王杰；

【导师】 程振洲； 廖志杰；

【作者基本信息】 天津大学 ， 工程（专业学位）， 2021， 硕士

【摘要】 水分子传感在生物制药、精确农业、化学工业以及食品检验等领域有广泛应用。光学水分子传感探针具有制备简单、稳定性高、响应速度快等优势,近年来受到了广泛关注。稀土掺杂的上转换纳米颗粒是一种极具前景的光学水分子传感探针,具有光稳定性高、响应速度快、体积小和无背景荧光信号的优势而备受关注。然而,稀土掺杂的上转换纳米颗粒水分子传感探针的传感机理研究还处于初始阶段,并且具有传感灵敏度较低等不足。本论文选择了掺Tm³⁺离子上转换纳米颗粒,研究了其水分子传感机理和特性。本论文的主要内容有:（1）理论研究了掺Tm³⁺离子纳米颗粒的上转换发光机理。以球状Na Gd F₄:Yb³⁺/Tm³⁺纳米颗粒为对象,研究了敏化剂Yb³⁺离子和激活剂Tm³⁺离子的物理特性、敏化剂Yb³⁺离子与激活剂Tm³⁺离子之间的能量传递效率以及纳米颗粒的形貌几何对其发光效率的影响。（2）数值模拟了基于单个NaGdF₄:Yb³⁺/Tm³⁺上转换微米棒的水分子传感探针。为了提升基于上转换纳米颗粒的水分子传感探针的传感灵敏度,以Tm³⁺离子作为发光中心,引入了回音壁模式共振结构,提高光与水分子的作用距离。相比于传统的基于荧光发光的水分子传感探针,基于回音壁模式激光的水分子传感探针的灵敏度理论上提升了将近一个数量级。同时,研究了指示波长、敏化剂离子和激活剂离子的掺杂浓度、回音壁微腔的品质因子以及泵浦功率对其传感灵敏度的影响。（3）实验研究了NaLuF₄:Yb³⁺/Tm³⁺/Gd³⁺上转换纳米颗粒水分子探测。利用溶剂热法制备了NaLuF₄:Yb³⁺/Tm³⁺/Gd³⁺上转换纳米颗粒,研究了指示波长、敏化剂离子和激活剂离子的掺杂浓度对其传感灵敏度的影响,实现了在无水乙醇中灵敏度为6.141%/vol%的水分子传感,制备了包覆有上转换纳米颗粒的微光纤水分子传感探针,并实现了环境中水分子传感。更多还原

【Abstract】 Water molecule sensing is of great significance in the fields of biomedicine,precision agriculture,chemical industry,and food inspection.In recent years,optical water molecule probes have attracted much attention due to the advantages of easy preparation,fast response,and high stability.As one of optical water molecule probes,rare-earth-ion-doped upconversion nanoparticles have aroused great research interest because of the advantages of high photostability,fast response speed,small volume,and free of autofluorescence background.However,water molecule probes based on upconversion nanoparticles still have the disadvantages of low sensitivity and lack of a clear understanding of the sensing mechanism.In the thesis,I selected Tm³⁺ions as the luminescent ions of upconversion nanoparticles,and studied their characteristics and mechanisms for water molecule sensing.The main contents are as follows:（1）I theoretically optimized the upconversion luminescence characteristics of nanoparticles with Tm³⁺ions as luminescent centers.The influences of the physical properties of sensitizer Yb³⁺ions and activator Tm³⁺ions,energy transfer efficiency between sensitizer Yb³⁺ions and activator Tm³⁺ions,and morphological geometry of the Na Gd F₄:Yb³⁺/Tm³⁺nanoparticle on the luminescence efficiency were studied.（2）I numerically simulated a water molecule probe based on a single NaGdF₄:Yb³⁺/Tm³⁺upconversion microrod.In order to improve the sensitivity of water molecule probes based on upconversion nanoparticles,I chose Tm³⁺ions as the luminescent centers,and employed a whispering gallery mode resonator.Compared with traditional water molecule probes based on upconversion nanoparticles,the sensitivity of the water molecule probe based on the whispering gallery mode resonator was improved by about an order of magnitude in theory.Moreover,the influences of the indicator wavelength,doping concentration of sensitizer Yb³⁺ions and activator Tm³⁺ions,quality-factor of the microcavity,and pump power on the detection sensitivity were studied.（3）I experimentally studied NaLuF₄:Yb³⁺/Tm³⁺/Gd³⁺upconversion nanoparticles for water molecule probing.First,I prepared the Na Lu F₄:Yb³⁺/Tm³⁺/Gd³⁺upconversion nanoparticles based on the solvothermal method,and studied the influences of the indicator wavelength,doping concentration of sensitizer ions and activator ions on the sensitivity.Then,I demonstrated the sensitivity of water molecule probing in anhydrous ethanol as 6.141%/vol%.Finally,I developed the upconversion-nanoparticle-coated micro-fiber water molecule probe,for the sensing of water molecules.更多还原