Recently, surface plasmon resonance (SPR) effects have been widely used to construct photocatalysts which are active in the visible spectral region. Such plasmonic photocatalysts usually comprise a semiconductor material transparent in the visible range (such as TiO2) and plasmonic nano-objects (e.g., Au nanoparticles (Au NPs)). Specific SPRs, though, only partially cover the visible spectrum and feature weak light absorption. Here, we explore the unique role played by whispering gallery mode (WGM) resonances in the expression of the photocatalytic activity of plasmonic photocatalysts. Using numerical simulations, we demonstrate that, by solely exploiting a proper geometrical arrangement and WGM resonances in a TiO2 sphere, the plasmonic absorption can be extended over the entire visible range and can be increased by more than 40 times. Furthermore, the local electric field at the Au-TiO2 interface is also considerably enhanced. These results are experimentally corroborated, by means of absorption spectroscopy and Raman measurements. Accordingly, such WGM-assisted plasmonic photocatalysts, when employed in water splitting experiments, exhibit enhanced activity in the visible range. Our findings show a promising and straightforward way to design full solar spectrum photocatalysts.

Plasmonic enhanced upconverting nanoparticles were constructed for visible to near-infrared light-driven photo-polymerization.

Charge transport in organic semiconductors is notoriously extremely sensitive to the presence of disorder, both internal and external (i.e., related to interactions with the dielectric layer), especially for n‐type materials. Internal dynamic disorder stems from large thermal fluctuations both in intermolecular transfer integrals and (molecular) site energies in weakly interacting van der Waals solids and sources transient localization of the charge carriers. The molecular vibrations that drive transient localization typically operate at low‐frequency (

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Plasmonic Au nanoparticle (NP)-loaded hierarchical hollow porous TiO spheres are designed and synthesized with the purpose of enhancing the overall catalytic activity by introducing the Au plasmonic effect into the system, where Au NPs themselves are catalytically active. The constructed nanohybrid exhibits both high activity in 4-nitrophenol reduction, compared to all of the previously reported Au-based catalysts, and high selectivity. The synergy of the inherent catalytic property of Au NPs and the plasmonic effect (mainly via hot electron transfer) under irradiation is confirmed by a series of control experiments. The specifically designed, porous hollow structure also greatly contributes to the good catalytic activity because it provides a large surface area, facilitates reactant adsorption, and hinders charge recombination. In addition, theoretical calculations reveal that such a structure also leads to an increase in light absorption of about 21% in the range of 400-800 nm with respect to a uniform water-TiO background featuring the same filling factor. This work provides insight into the rational design of plasmon-enhanced catalysts that will show their versatility in various electro-/photocatalysis.

The TiO2/Au nanostructure has been acknowledged as one of the most classic visible-light active photocatalysts due to the surface plasmon resonance (SPR) of Au nanoparticles. In many cases, the SPR effect only features weak visible light absorption in conventional TiO2/Au nanostructures. Here, we demonstrate a design of TiO2/Au/TiO2 with a combination of whispering gallery mode (WGM) resonances and SPR for efficient visible-light-driven photocatalysis. Escherichia coli (E. coli) were used as natural reactants as well as a template to construct an E. coli-like TiO2/Au/TiO2 nanostructure. Using numerical simulations, we show that the E. coli-like TiO2 capsule acts as the WGM resonator to interplay with the SPR effect of the Au NPs on TiO2 surface, which leads to a significant increase of visible light absorption and the local field enhancement at the Au–TiO2 interface. Accordingly, with the synergistic effect of WGM and SPR, the E. coli-like TiO2/Au/TiO2 nanostructure exhibits enhanced photocatalytic activity in the visible range. Our work reveals a promising bioapproach to a design highly visible light active plasmonic photocatalyst.

Since the birth of quantum mechanics the construction and control of novel hybrid quantum states are among the dream targets of scientists. In this regard, due to recent technological advances, hybrid states based on strong coupling occurring between light and matter have become a laboratory reality. For example, it is demonstrated that strong coupling involving microcavities or surface plasmon polaritons shows great potential for novel nanoplasmonic devices such as lasers, all-optical switching, field-effect transistors, and for the evergreen field of quantum computation. Further developments in this field require, however, a better understanding of the underlying mechanisms governing strong coupling, especially from a time-dependent point of view, time-resolved spectroscopy being one of the leading experimental approaches to address this aspect. In this perspective, after a brief introduction of the strong coupling concept, the recent research progress on the dynamics of strongly coupled systems involving J-aggregates, broadly absorptive dyes, semiconductor quantum dots, and perovskite films with either microcavities or surface plasmons polaritons is summarized and discussed. Finally, challenges and perspectives for developing strong coupling concept are further illustrated, with special attention to phonon-photon interaction, as one of the most intriguing topics in condensed matter physics.

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