Ultrafast and Long-Range Energy Transfer from Plasmon to Molecular Exciton

Abstract

By using a model interface consisting of a metallic grating and zinc phthalocyanine (ZnPc) molecules, we temporally and spatially resolve the energy transfer process from plasmon to molecular exciton via the plasmon-induced resonance energy transfer mechanism. It is found that the energy transfer can occur within 30 fs for a distance of 20 nm. The energy transfer range is much larger than that of typical hot carrier transfer and molecule-to-molecule energy transfer processes. Hence, this ultrafast and long-range plasmon-induced energy transfer channel is especially useful for boosting the exciton/free carrier generation yield in semiconductor layers. Moreover, the enhancement in the exciton production yield does not diminish even when the photon energy is lowered toward the optical absorption edge of ZnPc. Therefore, the observed energy transfer process can extend the optical absorption to frequencies below the optical bandgap of the molecule.

Tailoring Hot-Carrier Distributions of Plasmonic Nanostructures through Surface Alloying

“…Assuming that the reaction barrier is lowered by an occupation change in an orbital of the reactant, the charge transfer can take place either directly by the LSP dephasing into a charge transfer excitation ,,, or indirectly by scattering of a HC from the reactive surface of the NP. In the latter case, HCs need to be generated at the surface (directly through the decay of the LSP or through electromagnetic field enhancement, often called plasmon induced resonant energy transfer ,, ) or scattered from HCs generated throughout the NP . To add further complexity, all processes eventually lead to local heating, which by itself usually increases catalytic activity, and care needs to be taken to disentangle these effects experimentally. ,− Theoretical and computational modeling can provide insights into these processes, allowing the rational design of efficient devices. ,,,,,,− Strategies for optimizing HC generation rates and tailoring HC distributions are particularly valuable.…”

Active Control of Energy Transfer in Plasmonic Nanorod–Polyaniline Hybrids

“…Because of its reversible and controllable spectral modulation, PANI is a promising acceptor to couple with a plasmonic donor while providing ease of incorporation into existing platforms. ,,− Single-particle spectroscopy provides insight into changes to the scattering of single-AuNR–PANI hybrids by monitoring the plasmon resonance energy (E res ) and line width (Γ) without the presence of ensemble averaging inherent to bulk measurements. By monitoring changes to the single-particle Γ, RET efficiency (η RET ) can be determined, thereby showing how AuNR–PANI hybrids can be used to control the dynamic tuning of optical and electronic properties at soft interfaces. ,,− In this study, the single-particle Γ reports on changes in RET in AuNR–PANI hybrids as the protonation state of PANI is switched by pH. Correlated plasmon spectra of AuNR–PANI hybrids are captured under both acidic and basic conditions by using a fluidic cell on an inverted hyperspectral dark-field microscope.…”