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Iagatti A, Patrizi B, Basagni A, Marcelli A, Alessi A, Zanardi S, Fusco R, Salvalaggio M, Bussotti L, Foggi P. Photophysical properties and excited state dynamics of 4,7-dithien-2-yl-2,1,3-benzothiadiazole. Phys Chem Chem Phys 2018; 19:13604-13613. [PMID: 28518198 DOI: 10.1039/c6cp08721c] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The relationships between the photophysics and structural properties of 4,7-dithien-2-yl-2,1,3-benzothiadiazole as a function of solvent polarity are investigated both experimentally and by computational methods. Stationary fluorescence measurements are consistent with a model envisaging the presence of three types of conformers in equilibrium in the ground state. They are characterized by different relative orientations of the thiophene rings. Due to a low rotational barrier, the sample in solution is characterized by a distribution of relative internal orientations. By applying the Kawski method, we evaluate the average dipole moment of ground and excited states of the three types of conformers. The ground state dipole moments are small and similar for the three types of conformers. On the contrary, dipole moments differ substantially in the excited state. X-ray diffraction of a single crystal confirms the presence of an orientational disorder of thiophene rings. Transient absorption UV-visible spectroscopy experiments allows the identification of the main mechanisms responsible for the large Stokes shift observed in this push-pull molecule. Time dependent spectra provide a picture of the relaxation processes occurring after excitation: the primary step is an internal charge transfer assisted by thiophene ring planarization which occurs on a time scale ranging from 0.88 to 1.3 picoseconds depending on solvent polarity. Moreover, time-resolved fluorescence measurements are consistent with a mechanism involving planarization accompanied by a stabilization of the charge transfer state as observed in polar solvents. In the latter, longer fluorescence lifetimes are observed along with a quantum yield decrease due to the activation of specific non-radiative relaxation channels. The photophysical behavior of 4,7-dithien-2-yl-2,1,3-benzothiadiazole in a solid matrix of polymethyl methacrylate is similar to that observed in solution, but the overall non-radiative process rate is slow with respect to that in the liquid phase. As a consequence, the radiative processes are enhanced giving rise to a fluorescence quantum yield of 90%. Such behavior is consistent with the proposed relaxation model.
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Affiliation(s)
- Alessandro Iagatti
- LENS (European Laboratory for Non-Linear Spectroscopy), via Nello Carrara, 1 50019 Sesto Fiorentino, Italy.
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2
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Tosi I, Segado Centellas M, Campioli E, Iagatti A, Lapini A, Sissa C, Baldini L, Cappelli C, Di Donato M, Sansone F, Santoro F, Terenziani F. Excitation Dynamics in Hetero-bichromophoric Calixarene Systems. Chemphyschem 2016; 17:1686-706. [PMID: 26867716 DOI: 10.1002/cphc.201501065] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Revised: 01/22/2016] [Indexed: 11/06/2022]
Abstract
In this work, the dynamics of electronic energy transfer (EET) in bichromophoric donor-acceptor systems, obtained by functionalizing a calix[4]arene scaffold with two dyes, was experimentally and theoretically characterized. The investigated compounds are highly versatile, due to the possibility of linking the dye molecules to the cone or partial cone structure of the calix[4]arene, which directs the two active units to the same or opposite side of the scaffold, respectively. The dynamics and efficiency of the EET process between the donor and acceptor units was investigated and discussed through a combined experimental and theoretical approach, involving ultrafast pump-probe spectroscopy and density functional theory based characterization of the energetic and spectroscopic properties of the system. Our results suggest that the external medium strongly determines the particular conformation adopted by the bichromophores, with a direct effect on the extent of excitonic coupling between the dyes and hence on the dynamics of the EET process itself.
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Affiliation(s)
- Irene Tosi
- Dipartimento di Chimica, UniversitĂ di Parma, Parco Area delle Scienze 17/a, 43124, Parma, Italy
| | | | - Elisa Campioli
- Dipartimento di Chimica, UniversitĂ di Parma, Parco Area delle Scienze 17/a, 43124, Parma, Italy
| | - Alessandro Iagatti
- LENS (European Laboratory for Non Linear Spectroscopy), via N. Carrara 1, 50019, Sesto Fiorentino (FI), Italy.,INO (Istituto Nazionale di Ottica), Largo Fermi 6, 50125, Firenze, Italy
| | - Andrea Lapini
- LENS (European Laboratory for Non Linear Spectroscopy), via N. Carrara 1, 50019, Sesto Fiorentino (FI), Italy.,Dipartimento di Chimica "Ugo Schiff", UniversitĂ di Firenze, via della Lastruccia 13, 50019, Sesto Fiorentino (FI), Italy
| | - Cristina Sissa
- Dipartimento di Chimica, UniversitĂ di Parma, Parco Area delle Scienze 17/a, 43124, Parma, Italy
| | - Laura Baldini
- Dipartimento di Chimica, UniversitĂ di Parma, Parco Area delle Scienze 17/a, 43124, Parma, Italy.
| | - Chiara Cappelli
- Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126, Pisa, Italy.
| | - Mariangela Di Donato
- LENS (European Laboratory for Non Linear Spectroscopy), via N. Carrara 1, 50019, Sesto Fiorentino (FI), Italy. .,INO (Istituto Nazionale di Ottica), Largo Fermi 6, 50125, Firenze, Italy. .,Dipartimento di Chimica "Ugo Schiff", UniversitĂ di Firenze, via della Lastruccia 13, 50019, Sesto Fiorentino (FI), Italy.
| | - Francesco Sansone
- Dipartimento di Chimica, UniversitĂ di Parma, Parco Area delle Scienze 17/a, 43124, Parma, Italy
| | - Fabrizio Santoro
- CNR-Consiglio Nazionale delle Ricerche, Istituto di Chimica dei Composti Organo Metallici (ICCOM-CNR), UOS di Pisa, Area della Ricerca via G. Moruzzi 1, I-56124, Pisa, Italy
| | - Francesca Terenziani
- Dipartimento di Chimica, UniversitĂ di Parma, Parco Area delle Scienze 17/a, 43124, Parma, Italy.
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3
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Park H, Heldman N, Rebentrost P, Abbondanza L, Iagatti A, Alessi A, Patrizi B, Salvalaggio M, Bussotti L, Mohseni M, Caruso F, Johnsen HC, Fusco R, Foggi P, Scudo PF, Lloyd S, Belcher AM. Enhanced energy transport in genetically engineered excitonic networks. NATURE MATERIALS 2016; 15:211-6. [PMID: 26461447 DOI: 10.1038/nmat4448] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2014] [Accepted: 09/10/2015] [Indexed: 05/19/2023]
Abstract
One of the challenges for achieving efficient exciton transport in solar energy conversion systems is precise structural control of the light-harvesting building blocks. Here, we create a tunable material consisting of a connected chromophore network on an ordered biological virus template. Using genetic engineering, we establish a link between the inter-chromophoric distances and emerging transport properties. The combination of spectroscopy measurements and dynamic modelling enables us to elucidate quantum coherent and classical incoherent energy transport at room temperature. Through genetic modifications, we obtain a significant enhancement of exciton diffusion length of about 68% in an intermediate quantum-classical regime.
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Affiliation(s)
- Heechul Park
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
- The David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Nimrod Heldman
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
- The David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Patrick Rebentrost
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Luigi Abbondanza
- Research Center for Non-Conventional Energy, Istituto eni Donegani, eni S.p.A., Novara 28100, Italy
| | - Alessandro Iagatti
- European Laboratory for Non-linear Spectroscopy, University of Florence, Sesto Fiorentino 50019, Italy
- INO CNR, Sesto Fiorentino 50019, Italy
| | - Andrea Alessi
- Research Center for Non-Conventional Energy, Istituto eni Donegani, eni S.p.A., Novara 28100, Italy
| | - Barbara Patrizi
- European Laboratory for Non-linear Spectroscopy, University of Florence, Sesto Fiorentino 50019, Italy
| | - Mario Salvalaggio
- Research Center for Non-Conventional Energy, Istituto eni Donegani, eni S.p.A., Novara 28100, Italy
| | - Laura Bussotti
- European Laboratory for Non-linear Spectroscopy, University of Florence, Sesto Fiorentino 50019, Italy
| | - Masoud Mohseni
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Filippo Caruso
- European Laboratory for Non-linear Spectroscopy, University of Florence, Sesto Fiorentino 50019, Italy
- QSTAR and Department of Physics and Astronomy, University of Florence, Florence 50125, Italy
| | - Hannah C Johnsen
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Roberto Fusco
- Research Center for Non-Conventional Energy, Istituto eni Donegani, eni S.p.A., Novara 28100, Italy
| | - Paolo Foggi
- European Laboratory for Non-linear Spectroscopy, University of Florence, Sesto Fiorentino 50019, Italy
- INO CNR, Sesto Fiorentino 50019, Italy
- Department of Chemistry, University of Perugia, Perugia 06123, Italy
| | - Petra F Scudo
- Research Center for Non-Conventional Energy, Istituto eni Donegani, eni S.p.A., Novara 28100, Italy
| | - Seth Lloyd
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Angela M Belcher
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
- The David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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4
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Azzaroli N, Lobello MG, Lapini A, Iagatti A, Bussotti L, Di Donato M, Calogero G, Pastore M, De Angelis F, Foggi P. Monitoring the intramolecular charge transfer process in the Z907 solar cell sensitizer: a transient Vis and IR spectroscopy and ab initio investigation. Phys Chem Chem Phys 2015. [DOI: 10.1039/c5cp03314d] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The excited state dynamics of Z907 in solution and on semiconductor substrates has been studied with ultrafast UV/Vis and IR spectroscopy and DFT/TDDFT calculations.
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Affiliation(s)
- Nicolò Azzaroli
- European Laboratory for Non Linear Spectroscopy (LENS)
- UniversitĂ di Firenze
- Florence
- Italy
| | - Maria Grazia Lobello
- Computational Laboratory for Hybrid Organic Photovoltaics (CLHYO)
- Istituto CNR di Scienze e Tecnologie Molecolari
- I-06123 Perugia
- Italy
| | - Andrea Lapini
- European Laboratory for Non Linear Spectroscopy (LENS)
- UniversitĂ di Firenze
- Florence
- Italy
- Dipartimento di Chimica “Ugo Schiff”
| | - Alessandro Iagatti
- European Laboratory for Non Linear Spectroscopy (LENS)
- UniversitĂ di Firenze
- Florence
- Italy
- INO-CNR
| | - Laura Bussotti
- European Laboratory for Non Linear Spectroscopy (LENS)
- UniversitĂ di Firenze
- Florence
- Italy
| | - Mariangela Di Donato
- European Laboratory for Non Linear Spectroscopy (LENS)
- UniversitĂ di Firenze
- Florence
- Italy
- Dipartimento di Chimica “Ugo Schiff”
| | | | - Mariachiara Pastore
- Computational Laboratory for Hybrid Organic Photovoltaics (CLHYO)
- Istituto CNR di Scienze e Tecnologie Molecolari
- I-06123 Perugia
- Italy
| | - Filippo De Angelis
- Computational Laboratory for Hybrid Organic Photovoltaics (CLHYO)
- Istituto CNR di Scienze e Tecnologie Molecolari
- I-06123 Perugia
- Italy
| | - Paolo Foggi
- European Laboratory for Non Linear Spectroscopy (LENS)
- UniversitĂ di Firenze
- Florence
- Italy
- INO-CNR
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Ragnoni E, Di Donato M, Iagatti A, Lapini A, Righini R. Mechanism of the Intramolecular Charge Transfer State Formation in all-trans-β-Apo-8′-carotenal: Influence of Solvent Polarity and Polarizability. J Phys Chem B 2014; 119:420-32. [DOI: 10.1021/jp5093288] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Elena Ragnoni
- LENS (European
Laboratory for Non-Linear Spectroscopy) via N. Carrara 1, 50019 Sesto Fiorentino (Florence) Italy
- INO (Istituto
Nazionale di Ottica), Largo Fermi 6, 50125 Firenze, Italy
| | - Mariangela Di Donato
- LENS (European
Laboratory for Non-Linear Spectroscopy) via N. Carrara 1, 50019 Sesto Fiorentino (Florence) Italy
- INO (Istituto
Nazionale di Ottica), Largo Fermi 6, 50125 Firenze, Italy
- Dipartimento
di Chimica “Ugo Schiff”, Università di Firenze, via della
Lastruccia 13, 50019 Sesto Fiorentino (Florence), Italy
| | - Alessandro Iagatti
- LENS (European
Laboratory for Non-Linear Spectroscopy) via N. Carrara 1, 50019 Sesto Fiorentino (Florence) Italy
- INO (Istituto
Nazionale di Ottica), Largo Fermi 6, 50125 Firenze, Italy
| | - Andrea Lapini
- LENS (European
Laboratory for Non-Linear Spectroscopy) via N. Carrara 1, 50019 Sesto Fiorentino (Florence) Italy
- INO (Istituto
Nazionale di Ottica), Largo Fermi 6, 50125 Firenze, Italy
- Dipartimento
di Chimica “Ugo Schiff”, Università di Firenze, via della
Lastruccia 13, 50019 Sesto Fiorentino (Florence), Italy
| | - Roberto Righini
- LENS (European
Laboratory for Non-Linear Spectroscopy) via N. Carrara 1, 50019 Sesto Fiorentino (Florence) Italy
- INO (Istituto
Nazionale di Ottica), Largo Fermi 6, 50125 Firenze, Italy
- Dipartimento
di Chimica “Ugo Schiff”, Università di Firenze, via della
Lastruccia 13, 50019 Sesto Fiorentino (Florence), Italy
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Iagatti A, Tarpani L, Fiacchi E, Bussotti L, Marcelli A, Foggi P, Latterini L. A steady-state and time-resolved photophysical study of CdTe quantum dots in water. Photochem Photobiol Sci 2014; 14:397-406. [PMID: 25428704 DOI: 10.1039/c4pp00300d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The exciton generation and recombination dynamics in semiconductor nanocrystals are very sensitive to small variations in dimensions, shape and surface capping. In the present work CdTe quantum dots are synthesized in water using 3-mercaptopropionic acid and 1-thioglycerol as stabilizers. Nanocrystals with an average dimension of 4.0 ± 1.0 and 3.7 ± 0.9 nm were obtained, when 3-mercaptopropionic acid or 1-thioglycerol, respectively, was used as a capping agent. The steady-state characterization shows that the two types of colloids have different luminescence behavior. In order to investigate the electronic structure and the dynamics of the exciton state, a combined study in the time domain has been carried out by using fluorescence time-correlated single photon counting and femtosecond transient absorption techniques. The electron-hole radiative recombination follows the non-exponential decay law for both colloids, which results in different average decay time values (of the order of tens of nanoseconds) for the two samples. The data demonstrate that the process is slower for 1-thioglycerol-stabilized colloids. The ultrafast transient absorption measurements are performed at two different excitation wavelengths (at the band gap and at higher energies). The spectra are dominated in both types of samples by the negative band-gap bleaching signals although transient positive absorption bands due to the electrons in the conduction band are observable. The analysis of the signals is affected by the different interactions with the defect states, due to ligand capping capacities. In particular, the data indicate that in 1-thioglycerol-stabilized colloids the non-radiative recombination processes are kinetically more competitive than the radiative recombination. Therefore the comparison of the data obtained from the two samples is interpreted in terms of the effects of the capping agents on the electronic relaxation of the colloids.
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Affiliation(s)
- Alessandro Iagatti
- European Laboratory for Non Linear Spectroscopy (LENS), UniversitĂ di Firenze, via Nello Carrara 1, 50019 Sesto Fiorentino, Florence, Italy
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7
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Recent Theoretical and Experimental Advances in the Electronic Circular Dichroisms of Planar Chiral Cyclophanes. ACTA ACUST UNITED AC 2010; 298:99-128. [DOI: 10.1007/128_2010_59] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
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