Synthesis of ferromagnetic cobalt nanoparticle tipped CdSe@CdS nanorods: critical role of Pt-activation

The synthesis of a ferromagnetic heterostructured material consisting of a CdSe@CdS nanorod attached to a single dipolar cobalt nanoparticle (CoNP) into a matchstick morphology is reported. CdSe@CdS nanorods were modified by an activation reaction with Pt(acac)(2) which enabled selective one-sided deposition of a dipolar metallic CoNP-tip via the thermolysis of Co-2(CO)(8) in the presence of polystyrene ligands. Small (<2 nm) PtNP-tips on CdSe@CdS nanorods were found to be responsible for the selective deposition of CoNP-tips onto one terminus per nanorod. The influence of the Pt-activation step for cobalt tipping was investigated by examination of numerous conditions and characterization of intermediates and materials using transmission electron microscopy and synchrotron X-ray diffraction.