Quantum dot synthesis

PbSe QDs were synthesized and purified using standard air-free techniques according to a previously published procedure¹⁴. Briefly, PbO (1.50 g), OA (5.00 g), and ODE (10.00 g) were mixed and degassed in a three-neck round-bottom flask at room temperature. The mixture was then heated at 120 °C under vacuum to form Pb(OA)₂ and dry the solution. After 1.5 h, the Pb(OA)₂ solution was heated to 180 °C under argon flow and 9.5 mL of a 1 M solution of TOP-Se containing 200 µL of DPP was rapidly injected into this hot solution. An immediate darkening of the solution was observed, and the QDs were grown for 105 s at ~160 °C. The reaction was quenched with a liquid nitrogen bath and injection of 10 mL of anhydrous hexanes. The QDs were purified in an N₂-filled glovebox (<0.5 ppm O₂) by adding 2 mL of toluene and 9 mL of acetonitrile to the reaction solution, collecting the QDs by centrifugation, performing 6–8 cycles of redispersion/precipitation using toluene/acetonitrile (3 mL/24 mL), and then drying and storing the QDs as a powder in the glovebox.