Emission Enhancement by Formation of Aggregates in Hybrid Chromophoric Surfactant Amphiphile/Silica Nanocomposites

摘要

Following to the recent development of the organic-templated growth of materials, new types of photonic hybrid composite materials have emerged whose structure and function are organized hierarchically. Ordered, periodic mesoscopic materials allow the construction of composites with many types of guest, such as organic molecules or polymers. These host-guest materials combine the high stability of the inorganic host system, a new structure-forming mechanism due to the confinement of guests in well-defined pore channels, and a modular composition. The inorganic framework serves to protect, stabilize, and orient the organic moiety inside it. Preparation methods, properties, and possible applications of chromophores in porous silica, molecular sieves, and minerals have been summarized in a recent review article. Inclusion of dye molecules such as Coumarin 40, Rhodamine BE50, or Oxazine 1 inside the nanopores has been demonstrated by Schulz-Ekloff's and W?hrle's group, and in several other papers on this topic the concentration of dye molecules within the mesopores has been optimized by either inclusion of the dye molecules within preformed mesopores or during sol-gel synthesis. These materials showed an increase in photoluminescence intensity at only moderate dye concentrations. An MEH-PPV/silica nanocomposite that was produced for control of energy transfer and prepared by infiltration of MEH-PPV into a preformed, oriented, hexagonal silica mesophase was found to be heterogeneous, exhibiting two distinct conjugated polymer environments, that is, polymers inside and outside the hexagonally arranged pore channels of the silica particles.