Synthesis of PbS nanocrystals from sulfur–amine solutions at room temperature

Different sizes of PbS nanocrystals (NCs) were synthesized from sulfur–amine solution. Instead of using a hot-injection method, we prepared alkylamine-PbS NCs at room temperature in air, where the produced PbS NCs were dispersed in a non-polar solvent. In this work, alkylamine played dual roles as both reducing agent and surfactant. The size of PbS NCs could be tuned by controlling the reaction time, the concentration of precursor, the volume ratio of alkylamine to water, as well as the length of alkylamine. This new preparation method to produce PbS NCs especially using shorter length alkylamines such as octylamine as capping molecules, showed great potential in developing nanomaterials for optical devices.