Colloidal PbS nanocrystals with narrow photoluminescence spectra

Luminescent PbS nanocrystals have been synthesized by the colloidal method. PVA has been employed to modify the surface of prepared PbS nanocrystals and improve their optical properties. Optical and morphological characteristics of lead sulfide nanocrystals have been studied by high resolution electron microscopy and spectrophotometer. Optical absorption and photoluminescence (PL) studies of the PbS nanocrystals have shown the strong quantum confinement effects. For the first time, the prepared lead sulfide nanocrystals have emitted at 608 nm wavelength with narrow band width (21 nm) and high Stokes shift. Experimental results have shown that the surface charge traps have higher contribution to the optical properties of colloidal PbS nanocrystals and in our sample photoluminescence was due to hole relaxation. These properties made them a material with potential application in nanophotonics.