Synthesis of PbS/semiconducting polymer nanocomposites via thiolate decomposition

We report on a simple, low-temperature, two-step method to synthesize PbS quantum dots either in an organic solvent or directly in Poly(3-hexylthiophene-2,5-diyl) conducting polymer solutions by sulfur assisted thiolate decomposition. Thermogravimetry, differential thermal analysis, transmission electron microscopy and optical absorption measurements have been performed in order to characterize the nanocrystal precursors and colloidal suspensions with PbS nanocrystals and PbS/polymer composites. Results show that PbS nanoparticles may be obtained at temperatures much lower than the thiolate decomposition temperature which results in a suitable method to synthesize semiconductor nanoparticles in polymeric solutions avoiding polymer damage. Polymer has been found to help in the stabilization of the nanoparticles, retarding the precipitation of PbS as the sulfur amount is increased.