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Titolo:
How fast is interfacial hole transfer? In situ monitoring of carrier dynamics in anatase TiO2 nanoparticles by femtosecond laser spectroscopy
Autore:
Yang, XJ; Tamai, N;
Indirizzi:
Kwansei Gakuin Univ, Sch Sci, Dept Chem, Nishinomiya, Hyogo 6628501, JapanKwansei Gakuin Univ Nishinomiya Hyogo Japan 6628501 Hyogo 6628501, Japan
Titolo Testata:
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
fascicolo: 16, volume: 3, anno: 2001,
pagine: 3393 - 3398
SICI:
1463-9076(2001)3:16<3393:HFIIHT>2.0.ZU;2-R
Fonte:
ISI
Lingua:
ENG
Soggetto:
DIFFUSE-REFLECTANCE SPECTROSCOPY; ELECTRON-TRANSFER; FLASH-PHOTOLYSIS; COLLOIDAL TIO2; HETEROGENEOUS PHOTOCATALYSIS; CHARGE-TRANSFER; SEMICONDUCTOR; THIOCYANATE; PARTICLES; SYSTEMS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
36
Recensione:
Indirizzi per estratti:
Indirizzo: Tamai, N Kwansei Gakuin Univ, Sch Sci, Dept Chem, 1-1-155 Uegahara, Nishinomiya, Hyogo 6628501, Japan Kwansei Gakuin Univ 1-1-155 Uegahara Nishinomiya Hyogo Japan 6628501
Citazione:
X.J. Yang e N. Tamai, "How fast is interfacial hole transfer? In situ monitoring of carrier dynamics in anatase TiO2 nanoparticles by femtosecond laser spectroscopy", PHYS CHEM P, 3(16), 2001, pp. 3393-3398

Abstract

By comparing the transient absorption spectra of nanosized anatase TiO2 colloidal systems with and without SCN-, the broad absorption band around 520nm observed immediately after band-gap excitation for the system without SCN- has been assigned to shallowly trapped holes. In the presence of SCN-, the absorption from the trapped holes at 520 mn cannot be observed because of the ultrafast interfacial hole transfer between Tio(2) nanoparticles andSCN-. The hole and electron trapping times were estimated to be < 50 and 260 fs, respectively, by the analysis of rise and decay dynamics of transient absorption spectra. The rate of the hole transfer from nanosized TiO2 colloid to SCN- is comparable to that of the hole trapping and the time of formation of a weakly coupled (SCN . . . SCN)(.-) is estimated to be similar to 2.3 ps with 0.3 M KSCN. A further structural change to form a stable (SCN)(2)(.-) is observed in a timescale of 100 similar to 150 ps, which is almost independent of the concentration of SCN-.

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Documento generato il 28/03/20 alle ore 14:12:55