Decoupling Plasmonic Hot Electrons and Photothermal Effects at Ag/Eu2O3 Interfaces for Multimode Optical Memory

Abstract

Direct physical manipulation of rare-earth luminescent states is essential to overcome the chemical-response bottlenecks in optical storage. While plasmonic resonance offers a powerful platform for this purpose, the hot-electron injection and photothermal effects accompanying plasmon relaxation are inherently coupled, posing a critical challenge for their selective utilization. Here, we achieve active separation of plasmonic energy by constructing SiO2/Eu2O3/Ag and SiO2/Eu2O3/VO2/Ag heterostructures. In the direct-contact system, synergistic hot-electron injection and photothermal effects induce the Eu3+ crystal field distortion, driving the hypersensitive electric dipole transition to dominate over the magnetic dipole transition, thereby realizing wavelength-state storage with a luminescence contrast of 0.94. The introduction of a semiconducting VO2 interlayer acts as an electron barrier, blocking hot-electron injection while retaining the pure photothermal effect. This photothermal stimulation modulates the VO2/Eu2O3 interfacial defect states and V-3d electronic states, profoundly altering the Eu3+ excited-state dynamics (with the lifetime shortened from 67.79 to 1.97 μs), thereby enabling intensity-state storage. This dual-mode platform enables patterned recording alongside reversible self-erasure and nonvolatile operation. Our work offers a clear physical picture of diverting plasmonic energy channels toward low-energy, multidimensional optical storage.