Studies On Photoluminescence Manipulation Of Luminescent Materials By Photonic Crystals

In the early 1960 s,human entered a highly informative society.The rapid development of modern information technology caused many new materials coming into being.But the development of modern information technology industry couldn't be separated from the development of luminescent materials.It is the continuous innovation of luminescent materials,which makes the modern information technology industry flourish.Therefore,it is very important to study the luminescent materials from many aspects.There are many research groups in the world who have made great efforts to explore the luminescent materials in the fields of physics,chemistry,materials and electronics,and have made many remarkable achievements.When studying the photo-physical process of luminescent materials,we always focus on the regulation of photo-physical processes.The research results could help researchers find ways to enhance the fluorescence yield of luminescent materials.In the preparation of luminescent device,there are still some problems such as the easy crystallization of luminescent materials and low quantum yield.These problems could be solved by studying the photo-physical process of luminescent materials which could also broaden the application of luminescent materials.At the same time,these research results can provide a theoretical reserve for the developments and applications of new luminescent materials.In this paper,we manipulate the photoluminescence of organic small molecule dyes and gold nanoclusters by photonic crystals.We investigate our work from both steady and dynamic perspectives.The research results are as follows:1.The preparation method of three-dimensional opal poly-methyl-methacrylate(PMMA)photonic crystal has been described in detail.This kind of photonic crystals has a micro-porous structure and position-controllable photonic band gap.Both of them are capable of regulating the photoluminescence properties of organic small molecule dyes which were infiltrated in three-dimensional opal PMMA photonic crystals.The organic small molecule dyes in the aggregation state will produce strong intermolecular interactions because of the close distance between molecules and molecules,which will lead to aggregation induced fluorescence quenching.However,if we invited three-dimensional opal PMMA photonic crystals in the case of aggregation state,due to the micro-porous structure,three-dimensional opal PMMA photonic crystals can effectively increase the intermolecular distance and reduce the intermolecular interaction.Finally,it could inhibit the aggregation induced fluorescence quenching phenomenon and enhance the photoluminescence of organic small molecule dyes.We also find that the position of photonic bandgap of the photonic crystal can affect the energy transfer efficiency between the two kinds of organic small molecule dyes.By selecting the appropriate photonic bandgap,the spontaneous emission of energy donor could be suppressed and efficiency of energy transfer could be increased.2.We introduce the preparation process of two-dimensional coumarin 6(C-6)doped PMMA photonic crystals in detail.We also cover the 2D C-6 PMMA photonic crystal microspheres with translucent silver shells.It can be found that this kind of 2C C-6 photonic crystals has a photoluminescence phenomenon and its luminescence performance is better than that of C-6 in aggregation state.By analyzing the system of 2D C-6 photonic crystals and hemispherical silver shells,we find that energy transfer and local plasma resonance can affect the photoluminescence characteristics of 2D C-6 photonic crystals.When we cover the 2D C-6 photonic crystal with translucent silver shell,there is energy transfer between the 2D C-6 photonic crystal and the hemispherical silver shell layer.The photoluminescence spectrum of 2D C-6 photonic crystal could be influenced by the local plasma resonance.3.We use bottom-up method to synthesize a kind of Au(0)@Au(I)-thiolate core-shell nanoclusters and study its photoluminescence mechanism.After analyzing the steady-state emission spectra and wavelength-dependent dynamic curves of all the samples,we confirm the photoluminescence mechanism of this kind of Au nanoclusters.Based on this result,we further study the way to improve the photoluminescence properties of Au nanoclusters.According to the aggregation induced fluorescence enhancement effect,we find that alcohol can be used to dilute the concentrated Au nanoclusters aqueous solution,affected by solvent-induced aggregation,monodisperse Au nanoclusters would gather together,and thus could achieve the purpose of improving the light-emitting properties of Au nanoclusters.At the same time,by infiltrating the Au nanoclusters aqueous solution into 3D opal PMMA photonic crystals,the structure of 3D opal PMMA photonic crystals could inhibit the concentration quenching of Au nanoclusters and increase the photoluminescence of the Au nanoclusters.This method could further improve the Au nanoclusters photoluminescence characteristics.