Optical properties of colloidal PbTe and its oriented attachment

Abstract

PbTe nanocrystals (NCs) ranging in size from 3.5 to 7 nm have been synthesized using the hot-injection method. Based on these particles, a relation between the first absorption peak position and NC size has been established. Inductively coupled plasma optical emission spectrometry (ICP-OES) and energy dispersive x-ray spectroscopy (EDX) were combined with UV-vis-NIR spectroscopy to determine the NC concentration and molar absorption coefficient (ε). At 3.1 eV, ε scales with NC volume and is size independent. At the bandgap, ε is size-dependent because of quantum confinement effects. Different sizes of PbTe have been used for oriented attachment procedures. NCs of 5.74 nm are best suited for square oriented attachment procedures. Other attachment parameters that were investigated are: solvation of Pb-oleate in ethylene glycol, ligand density and size dispersion.