Quantum Dot Energy Circuits Based on Energy Transfer Driven by Plasmonic Metal Oxide Metasurfaces

Semiconductor heterostructures composed of multiple layers of different colloidal quantum dots (QDs) are key components for various devices, ranging from solar cells to light-emitting diodes. We investigate the control of energy transfer within a heterostructure comprising CdSe/ZnS and InP/ZnS core–shell QDs in interaction with a plasmonic metal oxide metasurface (PMOM). Such a metasurface is engineered with arrays of gold nanoantennas embedded in a thin Si layer and coated with an ultrathin film of Al oxide. We show that the bottom CdSe/ZnS QD layer, which is in direct contact with the metasurface, is driven into a state of directed energy transfer funneling. This behavior is attributed to localized surface plasmon resonances and hot-electron-induced defect passivation. In contrast, the top InP/ZnS QD layer is primarily influenced by surface lattice resonances, which enhance its receptivity and efficiency in capturing energy. The results suggest the formation of an energy circuit, wherein energy flows from the smallest CdSe/ZnS QDs to larger ones and is then routed to the upper layer, forming an energy gate toward the InP/ZnS QDs. The results offer a promising path toward making energy (excitons) transfer more efficient in complicated QD structures.