Published online by Cambridge University Press: 21 March 2011
For CdSe quantum dots (QDs) produced via high temperature pyrolysis in trioctylphosphine oxide (TOPO), a MnSe precursor such as Mn2(μ-SeMe)2(CO)8appears to be necessary to successfully incorporate low levels of Mn. A simple etching experiment and electron paramagnetic resonance (EPR) measurements reveal that most of the dopant atoms reside in the surface layers of the inorganic lattice. The dopant dramatically affects 113Cd solid state NMR spectra; the observed paramagnetic shift and decreased longitudinal relaxation time reproduce bulk material behavior. Paramagnetic atoms in QDs generate large effective magnetic fields, which implies that magneto-optical experiments can be performed simply by doping. Results from fluorescence line narrowing (FLN) studies on Mn doped CdSe QDs mirror previous findings on undoped QDs in an external magnetic field. Experimental fitting of photoluminescence excitation (PLE) spectra of doped QDs reveals that the effective absorption lineshape contains a new feature which is believed to be a previously unobserved – but theoretically predicted – optically dark fine structure state.