Highly photoluminescent PbS nanocrystals: The beneficial effect of trioctylphosphine

The unique intrinsic characteristics of colloidal lead chalcogenide nanocrystals (NCs) have prompted studies for their applications in optoelectronics and as biological markers. Lead chalcogenide semiconductors are applicable for the near-infrared due to their small bulk band gaps like PbS and PbSe as well as large exciton Bohr radii that permit for relatively huge nanocrystals while still maintaining quantum confinement. Although PbS NCs have low photoluminescence as of present, their synthesis has been reinvestigated to determine the specific influence of trioctylphosphine on their morphological and photochemical properties. As such, a modified synthesis of high-quality NCs using trioctylphosphine on their morphological and photochemical properties has been conducted. The investigation also studied the effects of molar ratios of reactants and dilution conditions on the properties of the NCs. The investigation showed that the introduction of trioctylphosphine does have a strong positive effect on the quality of the PbS NCs produced, as well as on their emission characteristics. Furthermore, the investigation have produced NCs with a narrow size distribution and high quantum yields.