Synthesis And Properties Of PDMS Transparent Composites With Lanthanide-doped Nanoparticles

Lanthanide doped nanomaterial is a kind of inorganic functional material that can be stable and ingredients controllable, which can be used in the laser, environmental lighting, solar cells and bio-labeling; furthermore, the nanocomposite containing nanoparticles and polymer has potential application in fields such as transparent display and photonics. In this context, we have made some process in upconversion of lanthanide doped nanomaterial, the luminescence of the nanocompoasites and improving efficiency of upconversion via simultaneous multi-wavelength excitation, the experiments are given below.Firstly, to realize the upconversion, the basic study of the lanthanide doped nanomaterial has been given. We synthesized nanoparticles by thermal decomposition with different lanthanide ions. Then we have gained upconversion luminescence of green, red, blue and white via energy transfer or energy level transition by excitation of 980nm and light is visible to naked eye. The energy level transition of the upconversion is explained by the assistance of energy level diagram.Secondly, we explored the luminescent properties of transparent organic/inorganic nanocomposite. Using the monodisperse particles in the last chapter, the nanocomposites were synthesized by physical mixing. The combination of emissions from different types of nanocrystals with selected ratios, therefore, was able to produce emission spectra at any color coordinate in a predictable manner. The emission color of this composite can be further tuned by the pumping intensity of the near infrared laser as well as the density of the nanocrystals in the composites. Stability can be maintained by excitation for long time. But the thermal effect might influence the luminescence.Finally, based on the above results, we expect that we can get the multicolor emission under the multi-wavelength excitation. In the first place, we prepared NaYF.4: Er nanocrystals with different concentration of lanthanide ions. Then we got the upconversion spectrum exciting the samples under 808nm,980nm or simultaneously, respectively. The luminescence intensity has been enhanced, the mechanism of upconversion and the possible reasons had been explored.