Thioacetamide as an Effective Sulfur Precursor for Preparation of Lead Sulfide Colloidal Quantum Dots

The synthesis of PbS colloidal quantum dots based on thioacetamide and lead(II) oxide has been studied. An environmentally friendly, amine-free method in the presence of only oleic acid is proposed for the preparation of nanoparticles smaller than 5 nm in size. The synthesis of larger particles requires the addition of oleylamine. The high efficiency of the fractional introduction of thioacetamide for optimizing the nanoparticle growth process is demonstrated. This method was used to synthesize quantum dots with an exciton peak at 2200 nm and a full width at half-maximum as small as 100 nm (25 meV).