In situ passivation for high-quality PbS colloidal quantum dots synthesized using a PbBr2 precursor

PbS quantum dots (QDs) have received considerable attention due to their broad and tunable absorption spectra, and because of the in situ passivation effect from PbBr2, the PbS QDs synthesized by PbBr2 precursor aroused many scholars’ interest. However, its synthesis process is complex, and the reaction mechanism remains unclear. In this work, we simplified the synthesis process by introducing oleic acid (OA) and 1-octadecene (ODE) into the lead precursor solution. Monodisperse PbS QDs ranging in size from 3.6 nm to 5.4 nm were synthesized successfully by adjusting the contents of ODE and oleylamine. Moreover, the use of PbBr2 as a lead precursor effectively reduced the surface defects of the PbS QDs by replacing surface hydroxyl (OH) groups. This resulted in improvement of the photoluminescence (PL) decay lifetime and stability of the QDs. Finally, the synthesized QDs were successfully applied in the solar cells. These findings contribute to a deeper understanding of leveraging the advantages of PbS QDs, particularly in the photovoltaic industry.