Electron and excitation energy transfers in covalently linked donor–acceptor dyads: mechanisms and dynamics revealed using quantum chemistry. Issue 1 (6th December 2017)

• Record Type: Journal Article
• Authors: Cupellini, Lorenzo; Giannini, Samuele; Mennucci, Benedetta
• Is Part Of: Physical chemistry chemical physics. Volume 20:Issue 1(2017)
• Page Start: 395
• Page End: 403
• Publication Date: 2017-12-06
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/c7cp07002k
• Languages: English
• ISSNs: 1463-9076

Abstract

Abstract : A quantum chemical strategy is developed to study photoinduced electron and energy transfer processes in covalently linked dyads. The strategy is applied to two zinc and free-based porphyrin–naphthalenediimide dyads in solution. Abstract : Photoinduced electron transfer (ET), hole transfer (HT), charge recombination (CR) and energy transfer (EET) are fundamental mechanisms, which occur in both natural and artificial light harvesting systems. Here, we present a computational strategy which determines ET, HT, CR and EET rates in a consistent way and merges them in a kinetic model to reproduce the net excited state dynamics. The effects of the solvent are included in all steps of the calculations making the present strategy a useful tool for a rational design of charge and energy transfer processes in complex systems. An application to covalently linked zinc and free-base porphyrin–naphthalenediimide dyads is presented. For each of the two systems, ultrafast optical spectroscopy experiments have shown a specific photophysics with different processes taking place simultaneously. The model reveals that such a diversity is mainly due to the different relative stability of the charge-separated state, while the electronic couplings for charge and energy transfer processes are quite similar in the two dyads.