Excitation-dependent ultrafast carrier dynamics of colloidal TiO2 nanorods in organic solvent

L. Triggiani, A. Brunetti, A. Aloi, R. Comparelli, M. Lucia Curri, A. Agostiano, M. Striccoli, R. Tommasi

Onderzoeksoutput: Bijdrage aan tijdschriftTijdschriftartikelAcademicpeer review

18 Citaten (Scopus)

Samenvatting

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 UV-vis 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.

Originele taal-2Engels
Pagina's (van-tot)25215-25222
Aantal pagina's8
TijdschriftJournal of Physical Chemistry C
Volume118
Nummer van het tijdschrift43
DOI's
StatusGepubliceerd - 30 okt. 2014
Extern gepubliceerdJa

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