Evaluation of the energetics of electron trap states at the nanocrystalline titanium dioxide/aqueous solution interface via time-resolved photoacoustic spectroscopy

Svetlana Leytner, Joseph T Hupp

Research output: Contribution to journalArticle

98 Citations (Scopus)

Abstract

Time-resolved photoacoustic spectroscopy (TRPAS) has been employed to probe directly the trap state energetics of photogenerated electrons in nanocrystalline colloidal titanium dioxide dispersed in aqueous solution. Deconvolution of the photoacoustic signals obtained following bandgap excitation allowed for separation of components associated with conduction band electron trapping, trapped electron-hole recombination, and a slower recombination step. The results indicate that the lifetime of the electron-hole pair is on the order of 25 ns with about 60% of the trapped electrons recombining on this time scale. The electron trapping sites were determined to lie, on average, 0.8 eV below the conduction band edge.

Original languageEnglish
Pages (from-to)231-236
Number of pages6
JournalChemical Physics Letters
Volume330
Issue number3-4
Publication statusPublished - Nov 10 2000

Fingerprint

Photoacoustic spectroscopy
Electron traps
photoacoustic spectroscopy
titanium oxides
traps
aqueous solutions
Electrons
evaluation
conduction bands
electrons
trapping
Conduction bands
Photoacoustic effect
Deconvolution
life (durability)
titanium dioxide
probes
Energy gap
excitation

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Spectroscopy
  • Atomic and Molecular Physics, and Optics

Cite this

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abstract = "Time-resolved photoacoustic spectroscopy (TRPAS) has been employed to probe directly the trap state energetics of photogenerated electrons in nanocrystalline colloidal titanium dioxide dispersed in aqueous solution. Deconvolution of the photoacoustic signals obtained following bandgap excitation allowed for separation of components associated with conduction band electron trapping, trapped electron-hole recombination, and a slower recombination step. The results indicate that the lifetime of the electron-hole pair is on the order of 25 ns with about 60{\%} of the trapped electrons recombining on this time scale. The electron trapping sites were determined to lie, on average, 0.8 eV below the conduction band edge.",
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N2 - Time-resolved photoacoustic spectroscopy (TRPAS) has been employed to probe directly the trap state energetics of photogenerated electrons in nanocrystalline colloidal titanium dioxide dispersed in aqueous solution. Deconvolution of the photoacoustic signals obtained following bandgap excitation allowed for separation of components associated with conduction band electron trapping, trapped electron-hole recombination, and a slower recombination step. The results indicate that the lifetime of the electron-hole pair is on the order of 25 ns with about 60% of the trapped electrons recombining on this time scale. The electron trapping sites were determined to lie, on average, 0.8 eV below the conduction band edge.

AB - Time-resolved photoacoustic spectroscopy (TRPAS) has been employed to probe directly the trap state energetics of photogenerated electrons in nanocrystalline colloidal titanium dioxide dispersed in aqueous solution. Deconvolution of the photoacoustic signals obtained following bandgap excitation allowed for separation of components associated with conduction band electron trapping, trapped electron-hole recombination, and a slower recombination step. The results indicate that the lifetime of the electron-hole pair is on the order of 25 ns with about 60% of the trapped electrons recombining on this time scale. The electron trapping sites were determined to lie, on average, 0.8 eV below the conduction band edge.

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