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

Lawrence J Hill,Philip T Dirlam,Nicola Pinna,Jeffrey Pyun,Younghun Sung,Walter Vogel,Nathaniel E Richey,Marc-Georg Willinger,Jared J Griebel,In-Bo Shim,Kookheon Char

doi:10.1039/c4ce00680a

Abstract

Activation of CdSe@CdS nanorods by a platinum deposition reaction enables selective deposition of a single dipolar cobalt nanoparticle tip per nanorod.

Highlights

We report on the synthesis of CdSe@CdS nanorods that incorporate a single dipolar cobalt nanoparticle (CoNP) tip per nanorod (Scheme 1)
Dipolar CoNP-tipped nanorods were synthesized over four steps using CdSe quantum dots and CdSe@CdS nanocrystal reagents, with the key step of the synthesis being nanorod activation with Pt(acac)[2] (Scheme 1)
CdSe quantum dots and CdSe@CdS nanorods were synthesized as previously reported,[25,53] and these nanorods served as substrates for the deposition of metal NPs to prepare the target dipolar CoNPtipped structure

Summary

Introduction

We report on the synthesis of CdSe@CdS nanorods that incorporate a single dipolar CoNP tip per nanorod (Scheme 1). The terminal deposition of PtNPs, or very small Pt clusters was investigated as a route to activate nanorods towards the deposition of dipolar CoNP-tips, based on our previously reported methodology for the installation of smaller CoNPtips.[25] CdSe@CdS nanorods were treated with Pt(acac)[2], HDD, OLAC, and OLAM for 8 min at 225 °C in phenyl ether, where low concentrations of Pt(acac)[2] (0.23 mM) resulted in nanorods having small PtNP-tips at a single terminus per nanorod, as observed by bright field TEM imaging (Fig. 1c).

Results

Conclusion