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A novel method is proposed to directly characterize the exciton‐plasmon coupling in a photosensitive nanoparticle‐on‐mirror (NPoM) nanocavity. Under the illumination of UV light, the localized surface plasmon resonance (LSPR) peaks of the nanocavity can be continuously tuned over a wide range (≈65 nm), enabling precise determination of the energy dispersion relationship of plexcitons in the nanocavity. The results indicate that the energy of Rabi splitting can be actively tuned from 65 meV (weak coupling) to 170 meV (strong coupling) by adjusting the LSPR peak of a specific nanocavity (particle size L≈55‐92 nm) to the exciton wavelength (the zero detuning). In addition, the criterion of strong coupling is optimized by introducing single‐particle absorption spectroscopy. The work offers an intuitive method for the strong coupling characterization in nanocavity, paving the way for the real‐time tuning of coupling strength over a wide range (100 meV) from weak to strong coupling regimes. [ABSTRACT FROM AUTHOR]

The laser‐irradiated aerosolized nanostructures with complex geometries offer unique opportunities to steer orientation‐dependent photoion emission for multiple applications of directional ion sources and photocatalysis. The orientation‐dependent photoion emission is characterized by measuring the distribution and probability on differently oriented nanostructures. This unique capability is achieved by introducing momentum‐to‐space orientation discrimination in the single‐shot velocity map imaging technique with the aerodynamic lens. The effect of geometry, polarization, and concentration to control the photoion emission from differently oriented nanostructures is introduced for optimizing the potential applications of photoion emission including directional tunable nanoanode and optical sensors. The mechanism behind controlling the photoion emission is visualized by the variations in the regions of high laser intensity inside the nanostructures responding to the orientation, geometry, and polarization. This work represents an advance in characterizing the photoion emission from the randomly oriented aerosolized nanostructures and facilitates the potential for combining with the pump–probe methods to provide an intuitive understanding of their real‐time ionization dynamics. [ABSTRACT FROM AUTHOR]

2D organic–inorganic hybrid perovskites are promising materials for next‐generation optoelectronic devices. Nevertheless, 2D perovskites still suffer from performance‐limiting trap states and possess fundamental photophysical effects that remain poorly understood. Herein, a photoinduced trap passivation for enhanced photoluminescence (PL) in 2D hybrid perovskites is reported. Under two‐photon excitation, the PL emission of the 2D hybrid perovskites exhibits a gradual increase in intensity and lifetime, due to the photoinduced trap passivation by interacting with oxygen in ambient environment. Interestingly, the PL increase shows distinct features at the surface and in the bulk of the 2D perovskites, which can be well revealed by a photoinduced oxygen‐diffused trap‐passivation model. Moreover, the PL increase and relaxation can recycle for several times, which suggests an excellent repeatability of the photoinduced trap passivation. The photoinduced trap passivation is critical for fundamental study of light–matter interaction in 2D perovskites, and shows great promise for improving the optoelectronic responses for functional devices. [ABSTRACT FROM AUTHOR]

Herein, a 20‐fold enhancement of the optical second harmonic generation (SHG) from WS2 monolayers by cooperating with SiO2 dielectric microspheres (MSs) is reported. Detailed experiment and simulation studies indicate that the SHG enhancement is dominantly originated by the enhanced excitation intensity and enlarged collection efficiency produced by the SiO2 MSs. The size effect of the SiO2 MS on the SHG enhancement is also systematically investigated. Moreover, the SHG enhancement is found to be very sensitive to the surrounding refractive index of the SiO2 MS, which advocates great promise for the photonic sensing applications. This work provides a low‐cost and efficient approach to enhancing the SHG emission, and demonstrates great potential for functional nanodevices based on hybrid dielectric structures. A 20‐fold enhancement of the optical second harmonic generation (SHG) from WS2 monolayers by cooperating with SiO2 dielectric microspheres (MSs) is reported. The SHG enhancement is attributed to the increased excitation intensity and enlarged collection efficiency produced by the SiO2 MSs. Moreover, a proof‐of‐concept photonic sensing application based on SHG is demonstrated. [ABSTRACT FROM AUTHOR]