A novel density-tunable nanocomposites of CdTe quantum dots linked to dendrimer-tethered multi-wall carbon nanotubes

A novel nanocomposite of CdTe–PAMAM–MWNT was synthesized by covalently linking CdTe quantum dots (QDs) onto highly water-soluble multi-wall carbon nanotubes (MWNTs) functionalized with dendritic poly(amidoamine) (PAMAM). The IR, UV–vis and TEM methods has been used for the characterization of the composites. A facile method for controlling the density of QDs in the composite by simply changing the ratio of CdTe QDs/PAMAM–MWNT, as was verified by the TEM images. The experiments revealed that PAMAM and PAMAM–MWNT, once covalently linked with CdTe QDs, had remarkable effect on their fluorescence property. The fluorescence intensity of the CdTe–PAMAM hybrid was substantially enhanced as a compared to that of QDs, and the fluorescence was quenched greatly when QDs reacted with PAMAM–MWNT. The experimentally observed phenomena indicate that electron and energy transfer took place efficiently between CdTe QDs, PAMAM and MWNTs in the novel composite. These nanocomposits might hold great potential in photoelectron device and biotechnology applications.