We study the plasmons confined at the gap between silver nanospheres and silver planar surfaces by means of angle- and space-resolved spectral cathodoluminescence. Plasmons in individual nanoparticles are excited by an electron beam, giving rise to light emission that is analyzed as a function of photon-energy, emission direction, and position of the beam spot. Gap plasmons are significantly red shifted due to the interaction between the particles and the metal substrate, and they are preferentially excited by positioning the beam close to the sphere centers, which results in an angular emission pattern similar to that of a dipole oriented along the surface normal. In contrast, weaker emission features are observed at higher-energies when the beam is grazing to the spheres, corresponding to the excitation of Mie plasmons like those of isolated particles, which display an angular pattern approximately mimicking a dipole parallel to the surface. Our measurements are in excellent agreement with simulations, thus providing useful insight into gap plasmons arising from the interaction between metal particles and metal substrates that are relevant for molecular sensing applications.

This manuscript reports the multi-functional boron complex presenting aggregation-induced emission (AIE), crystallization-induced emission enhancement (CIEE), and thermosalient behavior accompanying thermochromic luminescence during crystal-crystal transitions by employing the fused azomethine ligand. In particular, we propose that these properties can be explained by molecular "flexibility" toward external stimuli, including temperature changes and photo-excitation, and two types of crystal polymorphs with different absorption and luminescent properties were obtained. Optical measurements indicated that both polymorphs showed individual AIE and strong CIEE properties. From the investigations, the boron complex showed large structural relaxation and formed the bent structure in the excited state, followed by emission annihilation in the absence of structural restriction. In addition, it was shown that interconversion between these polymorphs could be reversibly induced by heating and cooling. The data from the single-crystal X-ray analyses suggested that alteration of crystal packing and intermolecular interaction should influence the luminescent chromism. Moreover, we also found that the crystals showed unusual mechanical behavior, such as hopping and fragmentation by heating and cooling, respectively, which is called thermosalient behavior. It was suggested that the loosely-fused structure could be responsible for expressing unique optical and mechanical properties.

A nonfullerene acceptor, TACIC, showed efficient light-harvesting, exciton diffusion, and charge transfer.

This review discusses pillar[n]arene-based MIMs such as rotaxanes, catenanes, polyrotaxanes, single-component mechanically self-locked molecules, and supramolecular polymers.

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