Preparation of high-performance micro-reactor luminescence of rare earth doped nano-particle nucleation and growth process and its control

Title: Preparation of high-performance micro-reactor luminescence of rare earth doped nano-particle nucleation and growth process and its control
　　Author: Zhu Xiaoxu
　　Degree-granting units: Donghua University
　　Keywords: rare earth doped;; nm light particles;; microfluidic reactor;; microwave radiation heating
　　Summary:
　　Inorganic light-emitting particles in the immunobiology and clinical laboratory science and other fields of study reflects the tremendous potential value. Such markers include fluorescent semiconductor quantum dots (Quantum Dots, QDs) and light rare-earth doped nano-particles. More current research QDs such as CdS, CdSe, CdTe and other organic synthesis, preparation rare earth magnets of harsh conditions, and the inherent light flashes, heavy metal toxicity and other disadvantages, limiting their application on biological markers. Rare-earth doped luminescent particles have low toxicity, Stokes shift width, and optical bleaching, blinking, and photochemical degradation of strong resistance, etc., and therefore, fluorescent markers in biological applications has a huge potential. But the traditional method of preparation of rare-earth doped luminescent particle size distribution there is a wide, large size, poor dispersion, high luminous efficiency is not defective, it is difficult to achieve biological fluorescent labels can be re-distributed applications, such as water-soluble and luminescent properties of the requirements of good .
　　In this paper, microfluidic reactor water consistency became LaF_3/LaPO_4: Ln ~ (3 +) (Ln ~ (3 +) = Ce ~ (3 +), Tb ~ (3 +), Eu ~ (3 +),) light-emitting nano-particles, combined with the micro-fluid control of the nanoparticles in the micro-space in the nucleation and growth process; improved by optimizing the process of re-dispersible nano-particles, water-solubility and fluorescence properties, and heated by microwave radiation to improve the micro-reaction device yield synthesis of nanoparticles. Full text of the main research work are as follows:
　　(1) the use of fine diameter of 300μm PTFE tube for microfluidic reactor to alcohol reagent (ethylene glycol (EG) and diethylene glycol (DEG), etc.) as solvent, at a lower reaction temperature (80 ~ 140 ℃), a shorter reaction time (5 ~ 60 s) the synthesis of light rare-earth doped nano-particles. By X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR Spectrum), UV-visible absorption spectra (UV-Vis Absorption) and fluorescence spectroscopy (PL Spectrum) by means of the prepared nano-particle-emitting structure and properties were characterized, with the result that microfluidic reactor luminescence of the synthesized nano-particles in the structure and performance than the traditional preparation methods have been significantly improved.
　　(2) based on high temperature rapid nucleation and slow growth of low-temperature crystallization of the theory, design a two-step microfluidic reactor, and the synthesis of light rare-earth-doped nano-particles. Through the characterization of that: two-step synthesis of LaF_3: Ce, Tb nano-particles with a narrow light-emitting particle size distribution, particle size 4 ~ 5 nm, and exhibit excellent water-soluble and can be re-dispersion; fluorescence properties have been significantly improved, especially in the fluorescence quantum yield compared to conventional sample preparation methods to obtain have been significantly improved, reaching 49%.
　　(3) the use of microwave radiation on the microfluidic reaction section heated, controlled nucleation and growth process, step to obtain rare-earth doped light-emitting particles. The characterization found that microwave radiation heating microreactors in the synthesis of crystalline nanoparticles, dispersion and morphology control has been significantly improved: get LaF_3: Ce, Tb monodisperse nanoparticles, the average particle size of 4.5 nm, LaPO_4: Ce, Tb nanorods of average length of 65 nm, average diameter of 12 nm; the two systems have shown excellent re-dispersible and water-soluble; especially fluorescence quantum yield and performance, than the oil bath temperature heating the sample to obtain significantly improved. In addition, the use of microwave radiation technology to solve the microfluidic reactor nanoparticles prepared by the problem of low productivity: access to the Ce ~ (3 +), Tb ~ (3 +) co-doped nanoparticles and LaPO_4 LaF_3 yield of nanoparticles reached 72.3%, respectively, and 91.2%. In the microwave-assisted synthesis of LaPO_4: Eu nanoparticles, we found a single crystal consisting of a few nanometers from the 25 ~ 30 nm http://www.chinamagnets.biz/Neodymium/Ball-Neodymium-Magnets.php grain size of the nanoparticles group, and showed a single dispersed form, resulting in a significant group-oriented behavior; description of the microwave microfluidic reactor radiation on the crystallization process has a special role.
　　(4) to raise the Eu ~ (3 +) doped LaF_3 fluorescent properties of nanoparticles difficult to design a microfluidic reactor and continuously synthesized LaF_3: Eu @ LaF_3 (Core @ Shell) core-shell structure of nanoparticles. The results show that the average particle size of 4.5 nm in the LaF_3: Eu core particle coated with a layer of about 1.5 nm thick LaF_3 matrix material, forming a diameter of 6nm nanoparticle core-shell structure, and to the crystalline particles , water solubility and fluorescence properties have been improved significantly.
　　Degree Year: 2010