Εξειδίκευση τύπου :	Άρθρο σε επιστημονικό περιοδικό
Τίτλος:	Oligothiophene/graphene supramolecular ensembles managing light induced processes: preparation, characterization, and femtosecond transient absorption studies leading to charge-separation
Δημιουργός/Συγγραφέας:	Stergiou A. Gobeze H.B. [EL] Πετσαλάκης, Ιωάννης Δ.[EN] Petsalakis, Ioannis D. Zhao S. Shinohara H. D'Souza F. [EL] Ταγματάρχης, Νίκος[EN] Tagmatarchis, Nikos
Εκδότης:	Royal Society of Chemistry
Ημερομηνία:	2015
Γλώσσα:	Αγγλικά
ISSN:	2040-3364
DOI:	10.1039/c5nr04875c
Περίληψη:	Advances in organic synthetic chemistry combined with the exceptional electronic properties of carbon allotropes, particularly graphene, is the basis used to design and fabricate novel electron donor-acceptor ensembles with desired properties for technological applications. Thiophene-based materials, which are mainly thiophene-containing polymers, are known for their notable electronic properties. In this frame moving from polymer to oligomer forms, new fundamental information would help for a better understanding of their electrochemical and photophysical properties. Furthermore, a successful combination of their electronic properties with those of graphene is a challenging goal. In this study, two oligothiophene compounds, which consist of three and nine thiophene-rings and are abbreviated 3T and 9T, respectively, were synthesized and noncovalently associated with liquid phase exfoliated few-layered graphene sheets (abbreviated eG), thus forming donor-acceptor 3T/eG and 9T/eG nanoensembes. Markedly, intra-ensemble electronic interactions between the two components in the ground and excited states were evaluated with the aid of UV-Vis and photoluminescence spectroscopy. Furthermore, redox assays revealed the one-electron oxidation of 3T accompanied by one-electron reduction due to eG in 3T/eG, whereas there were two reversible one-electron oxidations of 9T accompanied by one-electron reduction of eG9T/eG. The electrochemical band gap for the 3T/eG and 9T/eG ensembles were calculated and verified, in which the negative free-energy change for the charge-separated state of 3T/eG and 9T/eGvia the singlet excited state of 3T and 9T, respectively, were thermodynamically favorable. Finally, the results of transient pump-probe spectroscopy studies at the femtosecond time scale were supportive of charge transfer type interactions in the 3T/eG and 9T/eG ensembles. The estimated rates for intra-ensemble charge separation were found to be 9.52 × 109 s-1 and 2.2 × 1011 s-1, respectively, for 3T/eG and 9T/eG in THF, which reveal moderate to ultrafast photoinduced events in the oligothiophene/graphene supramolecular ensembles.
Τίτλος πηγής δημοσίευσης:	Nanoscale
Τόμος/Κεφάλαιο:	7
Τεύχος:	38
Σελίδες:	15840-15851
Θεματική Κατηγορία:	[EL] Φυσική και θεωρητική χημεία[EN] Physical and theoretical chemistry [EL] Φασματοσκοπία[EN] Spectroscopy
Αξιολόγηση από ομότιμους (peer reviewed):	Ναι
Κάτοχος πνευματικών δικαιωμάτων:	© The Royal Society of Chemistry 2015.
Όροι και προϋποθέσεις δικαιωμάτων:	All Open Access, Green
Σημειώσεις:	National Science Foundation, NSF: 1401188
Εμφανίζεται στις συλλογές:	Ινστιτούτο Θεωρητικής και Φυσικής Χημείας (ΙΘΦΧ) - Επιστημονικό έργο