Study On Optical Limiting Composites Of Phthalocyanines Doped Inorganic Marix

Phalocyanines are a kind of centrosymmetric planar organo-metallic molecules with an extensively delocalized two dimensional conjugated π-electron system which show a relatively large third order optical nonlinearity, varying upon central metal atom substitution and other factors. An important issue to be addressed for the successful application of MPc in optical area where will find interesting application is represented by their incorporation in a matrix to fabricate a solid state system. One of the practicing methods is sol-gel technique, which has been widely used to incorporate a variety of organic and organo-metallic molecules in inorganic host.This paper reports the successful preparation of MPc molecules doped silica gel glass composites obtained by sol-gel technique. The composites are transparent and homogeneous with required optical quality. The problem of doped MPc's dimerization is discussed and different kinds of solving methods are presented. The relationship between the composites' matrix and dopant component, structure and optical properties is studied. A series of important conclusions and creative achievements are obtained.Using pore structure measurement technique, the changes of pore structure of silica gel glass matrix under different sol-gel processing conditions are studied. And dimerization of different molecular structured MPcs is studied by UV/Vis absorption spectra. It is found that dimerization of doped MPc molecules is mainly affected by the structure characteristic of MPc molecule. In order to prepare composites with the least dimerization, it is important to design and assemble the target MPc molecule with desired structure, such as peripheral or axial substitutional groups. The optical limiting effect of the composites is measured at 532nm with 8ns pulses. The influence of different MPc doped concentrations, central metal ions, substitutional groups, dimerization ratios, and matrix on the composites' optical limiting effect is studied.