Study On Hydrothermal Synthesis And Vibrational Spectra Characterization Of LaPO₄and Dy-doped LaPO₄

With the rapid development of the society, luminescent materials are widely usedin many areas in today’s society. Due to its high luminous intensity, outstandingquantum efficiency and unique optical properties, rare earth fluorescent nanometerluminescent material has drown people’s attention and become the focus of people’sresearch. In the numerous nanostructured luminescent materials, rare earth dopedphosphate nanometer luminescent material based on rare earth phosphate matrix hasvery good luminescence properties, and in bad working environment it still maintainsgood stability, so it has a broad prospect application among all kinds of lighting anddisplay instrument. Therefore, to explore the regulations of the synthesis conditions,characterize and analysis its morphology structure, and further research on thestructure and performance after adulteration is of great significance.In this article, LaPO₄and Dy-doped LaPO₄：Dy³⁺are successfully synthesized byLa（NO₃）₃·6H₂O，Dy₂O₃（99.99%），（NH₄） H₂PO₄（98.5%） and concentrated nitric acidwith distilled water as solvent （pH value for4⁵） at100℃throw hydrothermalmethod, and transformed from the un-stable monazite phase to the stable monoclinicphase after heat-treatment at1000℃for three hours. The prepared powders werecharacterized by X-ray diffraction method （XRD）, scanning electron microscopy（SEM），EDS,TG, IR and Raman spectroscopy to characterized and analyzed theirobject, composition, morphology, structure characteristics,and vibration spectra. Theeffect of hydrothermal synthetic reaction temperature and reaction time to the phase composition and crystal growth of the samples are discussed. And the results showthat Lanthanum phosphate powders are prepared and Dy is successfully doped intothe lanthanum phosphate matrix. Hydrothermal synthesis reaction time andtemperature has no influence on the phase composition of the prepared powders, buthave a certain degree of influence on the crystal growth and morphology. At the sametime, the LaPO₄samples are doped with Dy by lanthanum dysprosium stoichiometricratio for1:0.02,1:0.04,1:0.05,1:0.06,1:0.08,1:0.10, and the vibration spectrum,including IR and Raman spectra after doped LaPO₄with different proportion of Dyare researched. Based on the comparative study of the two kinds of vibration spectrum,the changing regulations of the vibration spectrum for lanthanum phosphate afterdoped with different concentrations of Dy are found out. The results indicate that afterdoped with different concentrations of Dy, the changing regulation of the two kinds ofvibration line is consistent. That is to say, with the increasing of doping amounts, thelattice deformation increases at first and then decreases as the doping ratio rises, andwhen the lanthanum dysprosium stoichiometric ratio for1:0.06, the changingamplitude is the biggest, explaining that when the doping ratio is1:0.06, the influencefor matrix lattice structure is the biggest.