The Core/Shell Interface in InP/ZnSe Colloidal Quantum Dots

InP/ZnSe core–shell quantum dots (QDs) can emit spectrally narrow light with high efficiency, but the relation between the QD properties and the composition of the core–shell interface remains unclear. Here, we compare 4 different batches of InP/ZnSe QDs, formed with or without intermediate purification and InP surface oxidation before shell growth. Elemental analysis and solid-state NMR show that the presence of InCl 3 during ZnSe shell growth leads to indium incorporation into the ZnSe shell, while interfacial oxidation creates a polyphosphate at the core/shell interface. The sample in which both interfacial engineering approaches were applied features a higher photoluminescence quantum yield and the slowest biexciton Auger recombination rate. These findings support emerging insights on the InP/ZnSe core/shell interface in the literature and pave the way for further improving the optoelectronic properties of these materials by adjusting the interfacial composition.