Förster and nanometal surface-energy transfer in CsPbCl₃/Yb³⁺ quantum-cutting multilayer structures

Recently, in nanophotonics, thin metal films owing to the plasmon modes they support and their perovskite nanostructures exhibit novel optical properties, which have attracted considerable interest. Both the Förster resonant energy transfer (FRET) of the dopant-induced right-angled Yb³⁺-V_Pb-Yb³⁺ defect state and a pair of Yb³⁺ ions in all-inorganic perovskite nanocrystal (PeNC) CsPbCl₃:Yb³⁺ quantum-cutting (QC) materials and the nanometal surface-energy transfer (NSET) of the excitons of PeNC-Ag nanoparticles (NPs) were investigated experimentally in CsPbCl₃:Yb³⁺/PMMA/Ag/Si (CYAi = 1, 2, 3, 4, 5, 6), CsPbCl₃:Yb³⁺/PMMA/Si (CY), and CsPbCl₃/PMMA/Ag/Si (CA), representing three species of multilayer structures. It was found that due to the mediation of the Ag film and an increase in the interaction volume of donors-acceptors, FRET efficiencies increased from 26% to 66% as the spacer (or wave-guiding layer) thicknesses decreased from 63.7 to 17.8 nm. The energy-transfer efficiencies of CA in the NSET in the surface-surface scheme followed a d^-1.6-distance dependence. This distance dependence approached the d^-2-distance dependence expected of a point-to-surface or 0D-2D energy transfer (ET). The ET in quantum cutting (QC) modulated by plasmons undoubtedly paves a way for improving the FRET and NSET performances of materials.