Synthesis of Organic-Inorganic Nano-Composite Materials by the Assistance of Molecular Assembly Films and Investigation on Their Photo-and Electro-Chemical Properties

点击翻译按钮获取中文摘要

Exposure of metal ion-containing organized molecular assembly (OMA) films to H_2S gas resulted in the formation of size-quantized metal sulfides such as ZnS,CdS,PbS and Cu_2S in OMA films. When the metal sulfide-bearing composite films were subjected repeatedly to a set of immersion in aqueous solutions of the corresponding metal ions (I) and the exposure to H_2S gas (S), the growth of metal sulfides within a nano-order level was observed. The size of CdS formed in OMA films could be also controlled precisely by the occupied molecular area of OMA-constructing amphiphiles and the repetition number of the I-S cycle. Futhermore, synthesis of bimetallic sulfides in OMA films was also investigated. Mixed metal sulfides (M_zN_<1-z>S) were obtained by the sulfidation of salt-form Langmuir-Blodgett films containing both M and N ions, while Core (MS)-shell (NS) type binary metal sulfides ([MS]_x[NS]_y)were obtained by conbining I-S cycles for MS formation and those for NS formation in series. It was also found that the repeated cycle of intercalation of precursor ions and transformation of the precursor into inorganic compounds was applicable to synthesis of various organic-inorganic nano-composite systems, such as metal selenide- and Au particulate-bearing composite systems.Nonlinear optical properties of the metal sulfide-bearing composite system was evaluated by third harmonic generation and degenerate four-wave mixing techniques. The third-order optical nonlinearity of PbS-bearing composite system was comparable to or even larger than hitherto reported systems and was optimized by the regulation of the amount and size of PbS.