Luminescence Enhancement And Modulations On Luminescence Properties Of Rare-earth Doped Inorganic Materials Based On Three Dimensional Photonic Crystals

As the concept of photonic crystals (PhCs) mentioned by Yablonovitch andJohn in1987, these special structures have been widely studied and make it possibleto precisely manipulate photons. PhCs possess spatial periodicity in their dielectricconstants on the length scale of the optical wavelength. Consequently, PhCs respondto electromagnetic waves in a similar way to how atomic crystals respond toelectrons. Because an electronic band gap is created by the periodic arrangement ofatoms in a semiconductor, the periodic electromagnetic modulation created by thePhCs can yield a PSB (photonic stopband), a band of frequency for which lightpropagation in the PhCs is forbidden. Based on these properties, PhCs have attractedconsiderable attentions in different fields such as waveguides, near-zero thresholdlasers, light circuit, biosensors, etc. But at present there are still some problems:when the emitters couple on PhCs, the luminescence intensity can be largelyenhanced. But the essential mechanism should be further discussed. In my work, theessential mechanism is determined through PMMA opal PhCs coupled with[Ru(dpp)3]Cl2and the significant enhancement is used for oxygen sensing and ironions detection to achieve a high sensitivity and a low detection limit. On the otherhand, we demonstrate an efficient white light emission in Tm3+, Dy3+and Eu3+tri-doped YV1-xPxO4inverse opal PhCs. Base on the modulation of spontaneousemission and nonradiative processes, the quantum efficiency improves largely. Themodulation of up-conversion luminescence properties is also a hot topic. But thestudies mostly concentrate in oxide materials with large phonon energy. We havesuccessfully prepared NaYF4inverse opal PhCs with low phonon energy throughsolvent thermal method and studied the up-conversion properties. The results weobtained were shown as follows: [1] Tri-doped YV1-xPxO4: RE3+(RE=Tm, Dy, Eu) inverse opal PhCs arefabricated by the PMMA template method. As x=0.05, YV1-xPxO4: RE3+inverseopal PhCs demonstrate a maximum quantum yield. Using the PhC structure, theunexpected energy transfer process is effectively restrained and the quantum yield isconsiderably increased. Meanwhile, the color conversion between warm white andcold white light can be modulated by the PSB effect of PhCs.[2] A320-fold enhancement is observed as [Ru(dpp)3]Cl2molecules arespin-coated onto PMMA PhCs, which is the largest enhancement using3D PhCsuntil now. Its origin is mainly attributed to the suppression of energy transferbetween [Ru(dpp)3]Cl2molecules and non-radiative transition and the enhancementof the excitation field.[3]Base on the significant enhancement, The PMMA PhCs/Ru composites areused for traditional gas sensing, facilitated intracellular oxygen sensing and cellimaging; the PMMA PhCs/R6G are used for iron ions detection, which exhibithighly improved performance.[4] NaYF4inverse opal PhCs are successfully prepared through a noveltemplate-based solvent-thermal method for the first time and the synthetic conditionsare explored and discussed. Then the up-conversion luminescence properties aresystematically investigated by doping Yb3+, Er3+/Tm3+into NaYF4lattice. Theresults show a highly improved performance in up-conversion processes, especiallyhigh-order processes.