1,721,072 research outputs found
Cooperative effects to enhance two-photon absorption efficiency: intra- versus inter-molecular approach
Full text linkIn the search of new materials characterized by high two-photon absorption (TPA) efficiency, many efforts have been devoted to design chromophores with enhanced TPA responses progressively moving from linear chromophores such as dipoles and quadrupoles toward multimeric complex molecular architectures. This approach is mainly based on the optimization of intra-molecular charge transfer interactions. In contrast to the extensive investigations based on this intramolecular approach, the effect of inter-molecular interactions on TPA has not been fully elucidated, although theoretical studies predict that the presence of such interaction could induce large size-scalable TPA enhancements. Despite these promising predictions, only few investigations have been devoted to understand how intermolecular interactions affect the TPA response of molecular aggregates. Even less are the experimental studies that indeed compare the TPA efficiency of molecules in their monomeric and aggregated form and a thorough rationalization of the results was missing. This perspective aims to fill this gap providing a unified view of the efforts and the results obtained following this strategy
Quantum-coherent energy transfer: definitions, implications and experimental characterization
Full text linkSpectroscopic signatures of quantum-coherent energy transfer
No full textOne of the most surprising and significant advances in the study of the photosynthetic light-harvesting process is the discovery that the electronic energy transfer might involve long-lived electronic coherences, under physiologically relevant conditions. This means that the transfer of energy among different chromophores does not follow the expected classical incoherent hopping mechanism, but that quantum-mechanical laws can steer the migration of energy. The implications of such a quantum transport regime, although currently under debate, might have a tremendous impact on our way of thinking about natural and artificial light-harvesting. Central to these discoveries has been the development of new ultrafast spectroscopic techniques, in particular two-dimensional electronic spectroscopy, which is now the primary tool to obtain clear and definitive experimental proof of such effects. This review aims to provide an overview of the experimental techniques developed with the purpose of attaining a more detailed picture of the coherent and incoherent quantum dynamics relevant to energy transfer processes, not limited to the two-dimensional electronic spectroscopy. With the idea of summarizing the experimental and theoretical basic notions necessary to introduce the field, the connection between experimental observables and coherence dynamics will be analysed in detail for each technique, highlighting how electronic coherences could be manifested in different experimental signatures. Similarities and differences among coherent signals as well as advantages and disadvantages of each approach will be critically discussed. Current opinions and debated issues will be emphasised and some possible future directions to address still open questions will be suggested
2D Electronic Spectroscopic Techniques for Quantum Technology Applications
Full text link2D electronic spectroscopy (2DES) techniques have gained particular interest given their capability of following ultrafast coherent and noncoherent processes in real-time. Although the fame of 2DES is still majorly linked to the investigation of energy and charge transport in biological light-harvesting complexes, 2DES is now starting to be recognized as a particularly valuable tool for studying transport processes in artificial nanomaterials and nanodevices. Particularly meaningful is the possibility of assessing coherent mechanisms active in the transport of excitation energy in these materials toward possible quantum technology applications. The diverse nature of these new target samples poses significant challenges and calls for a critical rethinking of the technique and its different realizations. With the confluence of promising new applications and rapidly developing technical capabilities, the enormous potential of 2DES techniques to impact the field of nanosystems, quantum tec..
Coherent electronic energy transfer and organic photovoltaics
No full textOne of the most surprising and significant advances in the study of the photosynthetic light- harvesting process is the discovery that the electronic energy transfer (ET) might involve long-lived electronic coherences, also at physiologically relevant conditions. This means that the transfer of energy among different chromophores does not follow the expected classical incoherent hopping mechanism, but that quantum-mechanical laws can steer the migration of energy. The implications of such quantum transport regime, although currently under debate, might have a tremendous impact in our way to think about natural and artificial light-harvesting and suggest new directions for the development of artificial devices for the efficient capture and re-use of solar energy. Central to these discoveries has been the development of new ultrafast spectroscopic techniques, in particular two-dimensional electronic spectroscopy, which is now the primary tool to obtain clear and definitive experimental proof of such effects
Coherent Electronic Energy Transfer in Biological and Artificial Multichromophoric Systems
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