PREPARATION OF ORGANIC-INORGANIC NANO-COM POSITE FILMS BY THE ASSISTANCE OF MOLECULAR ASSEMBLY SYSTEMS

Preparations of an organic-inorganic nanocomposite film based on the s ynthesis of nano-sized inorganic materials in molecuar assembly films have been described. Exposure of metal stearate Langmuir-Blodgett (LB) films to H2S and HI gases results in the formation of size-quantized metal sulfides (CdS, ZnS, PbS) and PbI2, respectively, in the stearate LB films. When the metal sulfide-bearing composite film was subjected repeatedly to a cycle of immersion in aqueous solutions of the corres ponding metal ion (I) and the exposure to H2S gas (S), a nano-order in crease in the size of the metal sulfide was observed. The dimension of size-quantized CdS formed in LB films was also controlled precisely b y the occupied molecular area of amphiphiles which regulates the conce ntration of Cd2+ ions introduced in the hydrophilic interlayers. When the CdS-hearing stearate LB film was subjected alternately to the inte rcalation of Ph(2+) ions and sulfidation, a composite film in which si ze-quantized CdS and PbS coexisted was produced. On the structure of C dS-bearing stearate LB films, the existence of an ordered (crystalline ) region consisting of a layered structure of stearic acid and CdS she ets was suggested from TR and X-ray diffraction results. Third-order o ptical nonlinearity of the PbS-bearing composite system was relatively large and was optimized by the amount and size of PbS.