Localized Co²⁺ Doping of CdSe/CdS Seeded Nanorods

Abstract

Transition-metal-doped semiconductor nanocrystals have garnered interest in the field of spintronics because of their capability to couple an applied magnetic field to a photonic response, and vice versa. These structures are a synthetic challenge due to difficulties in controlling the distribution of dopants as well as introducing the impurity atoms into the host material in the first place. In this paper we present a route toward anisotropically Co2+-doped CdSe/CdS dot-in-rods, in which the dopants are localized at the nanorod tips, at a defined distance from the CdSe seed particle. The localized doping of seeded nanorods allows to gain a deeper understanding of the interaction of the dopant with an exciton through competitive photoluminescence quenching, highlighting the fact that the dopant locale is more important than dopant concentration. It also yields information about the kinetics that govern impurity diffusion, with an activation energy for Co2+ in nanocrystalline CdS of Ea = 61.11 kJ mol–1.