Abstract

The relaxation dynamics of charge carriers of organic capped TiO2 nanorods dispersed in chloroform was investigated by femtosecond transient absorption in a weak-excitation regime. Anisotropic TiO2 nanocrystals were excited in the UVvis range, using different pump wavelengths, namely above (300 nm), close to (350 nm), and below (430 nm) the direct band gap of anatase TiO2. We show that the ultrafast dynamics strongly depends on excitation wavelength and determine the time constants of all the processes entering the relaxation. Moreover, we demonstrate that two transient absorption bands at 500 and 700 nm, typically attributed to trapped h(+) and e, respectively, are accessible only when TiO2 is photoexcited well above the band gap, while there is no evidence of such bands when TiO2 is photoexcited close to or below its band gap. In such cases the observed dynamics are attributed to trapped excitons.

Autore Pugliese

• Striccoli Marinella , Comparelli Roberto

Tutti gli autori

• Triggiani L.; Brunetti A.; Aloi A.; Comparelli R.; Curri M. L.; Agostiano A.; Striccoli M.; Tommasi R.

Titolo volume/Rivista

Journal of physical chemistry. C

Anno di pubblicazione

2014

ISSN

1932-7447

ISBN

Non Disponibile

Numero di citazioni Wos

Nessuna citazione

Ultimo Aggiornamento Citazioni

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Numero di citazioni Scopus

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Ultimo Aggiornamento Citazioni

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Settori ERC

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Codici ASJC

Non Disponibile