Electrochemically modulated diffraction. A novel strategy for the determination of conduction-band-edge energies for nanocrystalline thin-film semiconductor electrodes

Xiaojun Dang, Aaron M. Massari, Joseph T Hupp

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

Micropatterned titanium dioxide thin-film electrodes exhibit efficient diffraction in the presence of aqueous or nonaqueous electrolyte solutions. The diffraction efficiency can be modulated electrochemically. At the wavelengths examined, the modulation is caused by changes in both real and imaginary components of the refractive index. The index changes, in turn, are caused by the addition of electrons to near-band-edge trap sites and by optical absorption by the trapped electrons. The onset potential for diffraction modulation provides a good measure of the potential of the electrode's conduction bandedge. Variable excitation wavelength measurements show that, after correction for absorption losses, the electrochemically induced changes in the proportion of light diffracted can be either positive or negative. The signs and the relative magnitudes of the wavelength-dependent changes are well described by a Kramers-Kronig analysis that assumes that changes in the real component of the refractive index dominate the response.

Original languageEnglish
Pages (from-to)555-558
Number of pages4
JournalElectrochemical and Solid-State Letters
Volume3
Issue number12
DOIs
Publication statusPublished - Dec 2000

Fingerprint

Conduction bands
conduction bands
Diffraction
Semiconductor materials
Thin films
Wavelength
Electrodes
electrodes
Refractive index
thin films
diffraction
Modulation
wavelengths
nonaqueous electrolytes
refractivity
modulation
Diffraction efficiency
Electrons
titanium oxides
Titanium dioxide

ASJC Scopus subject areas

  • Electrochemistry
  • Materials Science(all)

Cite this

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title = "Electrochemically modulated diffraction. A novel strategy for the determination of conduction-band-edge energies for nanocrystalline thin-film semiconductor electrodes",
abstract = "Micropatterned titanium dioxide thin-film electrodes exhibit efficient diffraction in the presence of aqueous or nonaqueous electrolyte solutions. The diffraction efficiency can be modulated electrochemically. At the wavelengths examined, the modulation is caused by changes in both real and imaginary components of the refractive index. The index changes, in turn, are caused by the addition of electrons to near-band-edge trap sites and by optical absorption by the trapped electrons. The onset potential for diffraction modulation provides a good measure of the potential of the electrode's conduction bandedge. Variable excitation wavelength measurements show that, after correction for absorption losses, the electrochemically induced changes in the proportion of light diffracted can be either positive or negative. The signs and the relative magnitudes of the wavelength-dependent changes are well described by a Kramers-Kronig analysis that assumes that changes in the real component of the refractive index dominate the response.",
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T1 - Electrochemically modulated diffraction. A novel strategy for the determination of conduction-band-edge energies for nanocrystalline thin-film semiconductor electrodes

AU - Dang, Xiaojun

AU - Massari, Aaron M.

AU - Hupp, Joseph T

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N2 - Micropatterned titanium dioxide thin-film electrodes exhibit efficient diffraction in the presence of aqueous or nonaqueous electrolyte solutions. The diffraction efficiency can be modulated electrochemically. At the wavelengths examined, the modulation is caused by changes in both real and imaginary components of the refractive index. The index changes, in turn, are caused by the addition of electrons to near-band-edge trap sites and by optical absorption by the trapped electrons. The onset potential for diffraction modulation provides a good measure of the potential of the electrode's conduction bandedge. Variable excitation wavelength measurements show that, after correction for absorption losses, the electrochemically induced changes in the proportion of light diffracted can be either positive or negative. The signs and the relative magnitudes of the wavelength-dependent changes are well described by a Kramers-Kronig analysis that assumes that changes in the real component of the refractive index dominate the response.

AB - Micropatterned titanium dioxide thin-film electrodes exhibit efficient diffraction in the presence of aqueous or nonaqueous electrolyte solutions. The diffraction efficiency can be modulated electrochemically. At the wavelengths examined, the modulation is caused by changes in both real and imaginary components of the refractive index. The index changes, in turn, are caused by the addition of electrons to near-band-edge trap sites and by optical absorption by the trapped electrons. The onset potential for diffraction modulation provides a good measure of the potential of the electrode's conduction bandedge. Variable excitation wavelength measurements show that, after correction for absorption losses, the electrochemically induced changes in the proportion of light diffracted can be either positive or negative. The signs and the relative magnitudes of the wavelength-dependent changes are well described by a Kramers-Kronig analysis that assumes that changes in the real component of the refractive index dominate the response.

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