Synthesis of Type I PbSe/CdSe Dot-on-Plate Heterostructures with Near-Infrared Emission

Zero-dimensional PbSe quantum dots are heterogeneously nucleated and grown onto two-dimensional zincblende CdSe nanoplatelets. Electron microscopy shows ad-grown dots predominantly decorate edges and corners of the nanoplatelets. Spectroscopic characterizations relate type I electronic alignment as demonstrated via photoluminescence excitation spectroscopy enhancement of near-infrared emission. Transient photoluminescence and absorption convey ultrafast transfer of excitons to the lower energy semiconductor dots. These structures combine benefits of large absorption cross sections of nanoplatelets and efficient near-infrared emission of PbSe with quantum confinement tuning of energy gap.