In Situ Tuning the Reactivity of Selenium Precursor To Synthesize Wide Range Size, Ultralarge-Scale, and Ultrastable PbSe Quantum Dots

PbSe quantum dots (QDs) have shown outstanding optoelectronic properties due to their extremely strong quantum confinement. However, the applications of PbSe QDs are substantially limited by their instability in air. Here, we developed a simple synthesis for PbSe QDs via in situ tuning the reactivity of selenium precursor. Because of in situ chloride passivation, the as prepared PbSe QDs showed excellent stability in air, demonstrated by the retention of absorption features and photoluminescence quantum yields (PL QYs) for different sizes after heated at 80 degrees C in air. Furthermore, the ligand exchanged electronic coupled PbSe QD thin films also had excellent stability in air even for large particle sizes. In addition, the PbSe QDs showed high PL QYs due to hybrid organic (oleate) and inorganic (Cl-) passivation. Monodispersive large (1st exciton peak > 2100 nm) and extremely small (1st exciton peak < 750 nm) PbSe QDs were achieved by careful control of particle growth. As a heating up method, this new synthesis was easily scaled up to produce 23.5 g PbSe QDs from one batch of reaction. The versatility of this new synthetic strategy was demonstrated by the synthesis of other metal selenide QDs such as CdSe and ZnSe QDs.