Synthesis of rare earth doped MoS2 by the co-pyrolysis of molecular precursors

The synthesis of Er- and Nd-doped MoS2 powders by the co-pyrolysis of molecular precursors is demonstrated by heating tetrakis-(diethyldithiocarbamato) molybdenum(IV) (Mo(DTC)4) and mono-1,10-phenanthroline tris-(diethyl dithiocarbamato) erbium(III) or mono-1,10-phenanthroline tris-(diethyl dithiocarbamato) neodymium(III) (Ln(DTC)3phen, where Ln = Er, Nd) to 500 °C for 1 h. Powder x-ray diffraction and Raman spectroscopy indicated that the resulting powders produced from this reaction are comprised of 0D nanoscale crystallites of the 2 H phase of MoS2. Spatial mapping of elements in these samples was performed in the scanning electron microscope at the microscale using energy dispersive X-ray spectroscopic mapping, which showed that the dopants are homogeneously distributed throughout the samples. Synchrotron radiation x-ray absorption measurements tentatively indicate that the dopants are incorporated within the MoS2 layers rather than being intercalated between them. Electron paramagnetic resonance spectroscopy and SQUID magnetometry demonstrated that rare earth doping of MoS2 significantly enhances the magnetic response of the material. Remarkably, the samples are found to remain paramagnetic down to temperature at least as low as 2 K.