Preparation of thermally stable well-dispersed water-soluble CdTe quantum dots in montmorillonite clay host media

In this work, a method to prepare a thermally stable QDs/clay powder is reported. First, several water soluble CdTe QDs characterised by different size-dependent emission wavelengths were synthesised through wet chemistry. Montmorillonite-Na+ clay in water was dispersed into a muddy suspension by sonication. Then, the clay-water suspension was used as the host media for CdTe QDs to prepare the QDs/clay powder by freeze drying. The experiments showed that QDs/clay powder could be re-dispersed in water without changing the luminescent property of the QDs; this process was reversible. EDX showed that Cd and Te elements existed in the QDs/clay powder and the XRD tests showed that the clay [001] reflection peaks for raw clay, QDs (lambda(em) = 514 nm)/clay and QDs (lambda(em) = 560 nm)/clay were the same, namely 2 theta = 7.4 degrees. Finally, QDs/clay powder was applied to the HOPE polymer extrusion process at 200 degrees C to produce thin films; the resultant QDs-polymer nanocomposite film exhibited strong fluorescence. (C) 2011 Elsevier Inc. All rights reserved.