Composites of quantum dots in anisotropic networks

摘要

Liquid crystal mixtures containing diacrylates and monoacrylates with carboxylic acid end groups were produced. Polymerization of the mixtures in the macroscopically oriented state led to the formation of hydrogen-bonded anisotropic networks with a high order parameter. Cadmium atoms were then incorporated in the networks and were subsequently converted to cadmium sulfide (CdS) quantum dots with a size of about 2nm using H_2S. Annealing the composites at temperatures above 80℃ increased the size of the quantum dots. The composites showed strong photoluminescence with a large Stokes shift associated with defect emission. With increasing size of the quantum dots the absorption and the emission bands shifted to longer wavelengths. The formation of the quantum dots in the composite led to a large increase in the mean refractive index of the system. When the size of the quantum dots was increased further, an increase in the mean refractive index of the composite was observed.