New Meta Nanomaterials Extension II of Optical Enhancement and Photorefractive Two-Beam Coupling - Synthesis and Fabrication of Quantum Dot NLO Polymer Composites.

摘要

Composites of CdS quantum dots and a new conjugated polymer were prepared by reacting CdS capped with (3-mercaptopropyl)trimethoxysilane (MPS) and a new conjugated copolymer at different pH (5.5., 7 and 10) at 50 C for 3 h, under magnetic stirring. Cadmium sulfide quantum dots with face centered cubic zinc blende structure and an average size of 3.02 0.46 nm (Figure 1) were prepared in the presence of MPS following the procedure of Fang, et al. The conjugated polymer, a poly(phenyleneethynylene) copolymer hereafter called pPE (OC12-Co-BzC11OH), was synthesized by Sonogashira-Heck reaction. 13C and 29Si SSNMR spectroscopy of CdS(MPS), the copolymer and composite was studied in order to investigate the functionalization at different pH. The hydrolysis of the methoxy groups of the silane and their successive polymerization, induced by the presence of the OH groups of the phenyleneethynylene, gives rise to superstructures of 200-600 nm in diameter. STEM analysis shows the presence of CdS clusters inside the larger particles and TEM tomography suggests a bilayer vesicle assembly. We note further that the tomographic STEM data and analyses demonstrate that the 3D vesicles formed in the nanocomposites are stable in the solid state under high vacuum conditions.