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Tailoring a Molecule’s Optical Absorbance Using Surface Plasmonics
摘要： Understanding the interaction of light with molecules physisorbed on substrates is a fundamental problem in photonics, with applications in biosensing, photovoltaics, photocatalysis, plasmonics, and nanotechnology. However, the design of novel functional materials in silico is severely hampered by the lack of robust and computationally efficient methods for describing both molecular absorbance and screening on substrates. Here we employ our hybrid G0[W0 + ?W]-BSE implementation, which incorporates the substrate via its screening ?W at both the quasiparticle G0W0 level and when solving the Bethe-Salpeter equation (BSE). We show this method can be used to both efficiently and accurately describe the absorption spectra of physisorbed molecules on metal substrates and thereby tailor the molecule’s absorbance by altering the surface plasmon’s energy. Specifically, we investigate how the optical absorption spectra of three prototypical π-conjugated molecules: benzene (C6H6), terrylene (C30H16) and fullerene (C60), depends on the Wigner-Seitz radius rs of the metallic substrate. To gain further understanding of the light–molecule/substrate interaction, we also study the bright exciton’s electron and hole densities and their interactions with infrared active vibrational modes. Our results show that (1) benzene’s bright E1 2u exciton at 7.0 eV, whose energy is insensitive to changes in rs, could be relevant for photocatalytic dehydrogenation and polymerization reactions, (2) terrylene’s bright B3u exciton at 2.3 eV hybridizes with the surface plasmon, allowing the tailoring of the excitonic energy and optical activation of a surface plasmon-like exciton, and (3) fullerene’s π ? π? bright and dark excitons at 6.4 and 6.8 eV hybridize with the surface plasmon, resulting in the tailoring of their excitonic energy and the activation of both a surface plasmon-like exciton and a dark quadrupolar mode via symmetry breaking by the substrate. This work demonstrates how a proper description of interfacial light–molecular/substrate interactions enables the prediction, design, and optimization of technologically relevant phenomena in silico.
关键词： Plasmonics,Optical Absorbance,π-conjugated molecules,Fullerene,Excitons,Hybrid Materials,Benzene,Surface Plasmonics,Magnetic,Infrared active vibrational modes,Wigner-Seitz radius,Optical,Terrylene
更新于2025-09-16 10:30:52
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Photophysical and photocatalytic properties of corrophyll and chlorophyll
摘要： Tetrapyrrolic macrocycles are well known photosensitizers, absorbing light in the ultraviolet and visible region. The quantum e?ciency of these naturally occurring compounds in optical processes, and the possibility of altering their behavior by modifying its constituent features, make them promising candidates for applications as Dye Sensitized Solar Cells (DSSC) and photocatalytic reactions. The time-dependent density-functional theory (TD-DFT) were used to study the optical and redox properties of chlorophyll and corrin-related molecules (corrophyll). The in?uence of the substituents and metallic atoms in their properties have been investigated. Our results show lower reduction potentials for corrophyll molecules compared with chlorophyll. The optical absorbance spectra of corrophyll without a metallic atom at their central rings shows a signi?cant blue-shift, as compared to their chlorophyll counterparts. The presence of Co(I) ion species at the corrophyll core leads to oxidation potentials below than that of water, which puts corrophyll ahead of traditional chlorophyll pigments as photocatalysts. We show that the substituents and the ions coordinated to the macrocycles play an important role in this phenomena. These ?ndings show the great potential of tuning the spectroscopic and reactive properties of tetrapyrrole macrocycles for applications in photocatalysis and optoelectronic devices, while keeping their essential structural features intact.
关键词： Corrole,Photophysics,Porphyrin,Electronic structure,TD-DFT,Optical absorbance,Photocatalysis
更新于2025-09-10 09:29:36