Low cost and large scale synthesis of PbS quantum dots with hybrid surface passivation

A low cost and large scale synthetic approach was developed for colloidal PbS quantum dots (QDs). The heat up strategy was adapted for large scale production, thioacetamide in oleylamine (OLA) was used as the sulphur precursor for low cost and safe synthesis, and PbCl2 in OLA was used as the lead precursor for a well passivated surface. Due to the balance between the diffusion coefficient and monomer oversaturation generated by the dissolution of small particles, an optimum growth temperature exists in the new synthesis. The synthesis was easily scaled up to produce 18 g of PbS QDs from one reaction batch, with a high chemical yield of ∼80% and the as synthesized QDs exhibit a high photoluminescence quantum yield of >40% and excellent air-stability of at least 60 days, due to the Cl− and oleate co-passivation.