A Multitechnique Physicochemical Investigation of Various Factors Controlling the Photoaction Spectra and of Some Aspects of the Electron Transfer for a Series of Push鈥揚ull Zn(II) Porphyrins Acting as
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- 作者：Alessio Orbelli Biroli ; Francesca Tessore ; Maddalena Pizzotti ; Cinzia Biaggi ; Renato Ugo ; Stefano Caramori ; Alessandro Aliprandi ; Carlo Alberto Bignozzi ; Filippo De Angelis ; Giacomo Giorgi ; Emanuela Licandro ; Elena Longhi
- 刊名：Journal of Physical Chemistry C
- 出版年：2011
- 出版时间：November 24, 2011
- 年：2011
- 卷：115
- 期：46
- 页码：23170-23182
- 全文大小：1160K
- 年卷期：v.115,no.46(November 24, 2011)
- ISSN：1932-7455
文摘
A multitechnique physicochemical comparative investigation involving TDDFT theoretical calculations, steady-state and time-resolved electronic absorption spectra, and electrochemical and photoelectrochemical investigations was carried out on a family of push鈥損ull porphyrinic sensitizers ([5-(4鈥?carboxy-phenylethynyl)-15-(4鈥?methoxy-phenylethynyl)-10,20-bis(3,5-di-tert-butylphenyl)porphyrinate]Zn(II) (1) and [5-(4鈥?carboxy-phenylethynyl)-15-(4鈥?N,N-dimethylamino-phenylethynyl)-10,20-bis(3,5-di-tert-butylphenyl)porphyrinate]Zn(II) (2) and the new fluorinated porphyrinic dye [5-(4鈥?carboxy-2鈥?3鈥?5鈥?6鈥?tetrafluorophenylethynyl)-15-(4鈥?N,N-dimethylamino-phenylethynyl)-10,20-bis(3,5-di-tert-butylphenyl)porphyrinate]Zn(II) (3)) with the aim of identifying the structurally related electronic properties at the basis of efficient interfacial charge separation. We found for all dyes a photoconversion nearly twice more effective for the B band than for the Q band, which could not be explained only by considerations based on the electron collection efficiency but also by a more energetically favorable electron injection from the S2 excited state. The lower photoconversion of the fluorinated dye 3, when compared to dyes 1 and 2, was explained not only by a more difficult absorption on the TiO2 photoanode but also by a lower electron injection efficiency and a less successful hole transfer to the electrolyte, leading to increased charge recombination.