A robust method for the synthesis of colloidal PbS nanosheets

In the synthesis of colloidal PbS nanosheets, acetic acid – either injected externally or produced during the reaction – has a significant effect on the growth of the nanosheets. When the acetic acid to lead molar ratio is above 1:8, no nanosheets are observed in the product. By replacing lead acetate with lead oxide to prepare the lead precursor for the reaction, the effect of acetic acid is avoided, resulting in a robust synthesis with nearly 100% success rate. In the new synthesis, the purity of trioctylphosphine (the co‐solvent for sulfur precursor) has no significant effect on the formation of nanosheets. Thickness tunability is achieved in the acetate‐free synthesis by tuning the reaction temperature. (© 2016 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)