Energy- and charge-transfer processes in flexible organic donor-acceptor dyads

The Rise and Future of Discrete Organic-Inorganic Hybrid Nanomaterials

Hybrid nanomaterials (HNs), the combination of organic semiconductor ligands attached to nanocrystal semiconductor quantum dots, have applications that span a range of practical fields, including biology, chemistry, medical imaging, and optoelectronics. Specifically, HNs operate as discrete, tunable systems that can perform prompt fluorescence, energy transfer, singlet fission, upconversion, and/or thermally activated delayed fluorescence. Interest in HNs has naturally grown over the years due to their tunability and broad spectrum of applications. This Review presents a brief introduction to the components of HNs, before expanding on the characterization and applications of HNs. Finally, the future of HN applications is discussed.

Synthesis and investigation on optoelectronic properties of mesogenic triphenylene–perylene dyads linked by ethynylphenyl bridges

Columnar mesogenic dyads consisting of triphenylene and perylene units are a novel kind of single-component photovoltaic materials.

Electronic energy and electron transfer processes in photoexcited donor-acceptor dyad and triad molecular systems based on triphenylene and perylene diimide units

We investigate the photophysical properties of organic donor-acceptor dyad and triad molecular systems based on triphenylene and perylene diimide units linked by a non-conjugated flexible bridge in solution using complementary optical spectroscopy techniques. When these molecules are diluted in dichloromethane solution, energy transfer from the triphenylene to the perylene diimide excited moieties is evidenced by time-resolved fluorescence measurements resulting in a quenching of the emission from the triphenylene moieties. Simultaneously, another quenching process that affects the emission from both donor and acceptor units is observed. Solution ultrafast transient absorption measurements provide evidence of photo-induced charge transfer from either the donor or the acceptor depending upon the excitation. Overall, the analysis of the detailed time-resolved spectroscopic measurements carried out in the dyad and triad systems as well as in the triphenylene and perylene diimide units alone provides useful information both to better understand the relations between energy and charge transfer processes with molecular structures, and for the design of future functional dyad and triad architectures based on donor and acceptor moieties for organic optoelectronic applications.

Structure–charge transfer property relationship in self-assembled discotic liquid-crystalline donor–acceptor dyad and triad thin films

Dynamics of the photo-induced charge transfer are correlated with the structural properties of self-assembled discotic donor–acceptor dyad and triad films.

Optical switching of radical pair conformation enhances magnetic sensitivity

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We propose to switch the conformation of radical pairs to control their reaction kinetics.

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The optical control does not interfere directly with the electron or nuclear spin dynamics.

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Our scheme may highly improve the sensitivity of chemical magnetometers.

The yield of radical pair reactions is influenced by magnetic fields well beyond the levels expected from energy considerations. This dependence can be traced back to the microscopic dynamics of electron spins and constitutes the basis of chemical compasses. Here we propose a new experimental approach based on molecular photoswitches to achieve additional control on the chemical reaction and allow short-time resolution of the spin dynamics. Our proposal enables experiments to test some of the standard assumptions of the radical pair model and improves the sensitivity of a paradigmatic model of chemical magnetometer by up to two orders of magnitude.

Unique piezochromic fluorescence behavior of dicyanodistyrylbenzene based donor-acceptor-donor triad: mechanically controlled photo-induced electron transfer (eT) in molecular assemblies

A novel donor-acceptor-donor triad that exhibits fluorescence on-off switching with high contrast ratio (ca. 10(3) ) in response to a mechanical stimulus in the solid state is reported. This system provides a very unique example of high-contrast fluorescence switching that is driven by a mechanical-force-controlled photo-induced electron transfer (eT) in molecular assemblies.