Efficient 2D to 0D Energy Transfer in HgTe Nanoplatelet-Quantum Dot Heterostructures through High-Speed Exciton Diffusion.

Large area absorbers with localized defect emission are of interest for energy concentration via the antenna effect. Transfer between 2D and 0D quantum-confined structures is advantageous as it affords maximal lateral area antennas with continuously tunable emission. We report the quantum efficiency of energy transfer in in situ grown HgTe nanoplatelet (NPL)/quantum dot (QD) heterostructures to be near unity (>85%), while energy transfer in separately synthesized and well separated solutions of HgTe NPLs to QDs only reaches 47 ± 11% at considerably higher QD concentrations.

On the inadequacy of Stern-Volmer and FRET in describing quenching in binary donor-acceptor solutions.

Quantitative fluorescence quenching is a common analytical approach to studying the mechanism of chemical reactions. The Stern-Volmer (S-V) equation is the most common expression used to analyze the quenching behavior and can be used to extract kinetics in complex environments. However, the approximations underlying the S-V equation are incompatible with Förster Resonance Energy Transfer (FRET) acting as the primary quenching mechanism.

Dielectric Screening Modulates Semiconductor Nanoplatelet Excitons.

The influence of external dielectric environments is well understood for 2D semiconductor materials but overlooked for colloidally grown II-VI nanoplatelets (NPLs). In this work, we synthesize MX (M = Cd, Hg; X = Se, Te) NPLs of varying thicknesses and apply the Elliott model to extract exciton binding energies-reporting values in good agreement with prior methods and extending to less studied cadmium telluride and mercury chalcogenide NPLs. We find that the exciton binding energy is modulated both by the relative effect of internal vs external dielectric and by the thickness of the semiconductor material.