Size-Programmed Synthesis of PbSe Quantum Dots via Secondary Phosphine Chalcogenides

摘要： In the most common syntheses of colloidal nanocrystal quantum dots (QDs) the size of the particle increases monotonically with reaction time. We have discovered a PbSe QD synthesis whereby size can be easily controlled by varying the side-chains of a secondary phosphine selenide precursor. The reaction runs to completion, and thus a desired QD diameter can be achieved by simply selecting an appropriate secondary phosphine. Quenching of the reaction to select a desired QD size is not required. For different secondary phosphine selenides, measurements of the precursor conversion rate show a direct relationship with final QD size, while P=Se bond strength calculations show an unexpected inverse relationship between QD size and P=Se bond strength. Finally, it is also demonstrated that secondary phosphine selenide precursors can provide an effective route for IV-VI QD syntheses on the large scale.