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STM-induced light emission from thin films of perylene derivatives on the HOPG and Au substrates.

Fujiki A, Miyake Y, Oshikane Y, Akai-Kasaya M, Saito A, Kuwahara Y - Nanoscale Res Lett (2011)

Bottom Line: A fluorescence peak with vibronic progressions with large Stokes shifts was observed on both highly ordered pyrolytic graphite (HOPG) and Au substrates, indicating that the emission was derived from the isolated-molecule-like film condition with sufficient π-π interaction of the perylene rings of perylenetetracarboxylic diimide molecules.The upconversion emission mechanism of the tunneling-electron-induced emission was discussed in terms of inelastic tunneling including multiexcitation processes.The wavelength-selective enhanced emission due to a localized tip-induced surface plasmon on the Au substrate was also obtained.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Precision Science & Technology, Graduate school of Engineering, Osaka University, 2-1 Yamada-oka, Suita 565-0871, Japan. fujiki@ss.prec.eng.osaka-u.ac.jp.

ABSTRACT
We have investigated the emission properties of N,N'-diheptyl-3,4,9,10-perylenetetracarboxylic diimide thin films by the tunneling-electron-induced light emission technique. A fluorescence peak with vibronic progressions with large Stokes shifts was observed on both highly ordered pyrolytic graphite (HOPG) and Au substrates, indicating that the emission was derived from the isolated-molecule-like film condition with sufficient π-π interaction of the perylene rings of perylenetetracarboxylic diimide molecules. The upconversion emission mechanism of the tunneling-electron-induced emission was discussed in terms of inelastic tunneling including multiexcitation processes. The wavelength-selective enhanced emission due to a localized tip-induced surface plasmon on the Au substrate was also obtained.

No MeSH data available.


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Bias voltage dependences of STM-LE spectra of PTCDI-C7 thin films on (a) HOPG and (b) Au substrates (It = 20 nA, acquisition time = 15 min). The arrow indicates the quantum cutoff energy (see text) of each sample voltage. The spectra are smoothened by averaging the 100 nearest points of the raw data.
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Figure 6: Bias voltage dependences of STM-LE spectra of PTCDI-C7 thin films on (a) HOPG and (b) Au substrates (It = 20 nA, acquisition time = 15 min). The arrow indicates the quantum cutoff energy (see text) of each sample voltage. The spectra are smoothened by averaging the 100 nearest points of the raw data.

Mentions: To discuss the mechanism of STM-LE emission from PTCDI-C7 in more detail, we determined the sample bias voltage dependence of the spectra of PTCDI-C7. Figure 6a,b shows the variation in the emission spectra as a function of the sample bias voltages on the HOPG and Au substrates, respectively. The arrows indicate the wavelengths of the quantum cutoff energies converted from the corresponding bias voltages. It was considered that the emission from the PTCDI-C7 thin film on the HOPG surface was excited by inelastic tunneling [31] because no polarity dependence of the STM-LE spectra was observed (data not shown), indicating that the injection-type electron-hole recombination mechanism, as in an OLED, is impossible.


STM-induced light emission from thin films of perylene derivatives on the HOPG and Au substrates.

Fujiki A, Miyake Y, Oshikane Y, Akai-Kasaya M, Saito A, Kuwahara Y - Nanoscale Res Lett (2011)

Bias voltage dependences of STM-LE spectra of PTCDI-C7 thin films on (a) HOPG and (b) Au substrates (It = 20 nA, acquisition time = 15 min). The arrow indicates the quantum cutoff energy (see text) of each sample voltage. The spectra are smoothened by averaging the 100 nearest points of the raw data.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211436&req=5

Figure 6: Bias voltage dependences of STM-LE spectra of PTCDI-C7 thin films on (a) HOPG and (b) Au substrates (It = 20 nA, acquisition time = 15 min). The arrow indicates the quantum cutoff energy (see text) of each sample voltage. The spectra are smoothened by averaging the 100 nearest points of the raw data.
Mentions: To discuss the mechanism of STM-LE emission from PTCDI-C7 in more detail, we determined the sample bias voltage dependence of the spectra of PTCDI-C7. Figure 6a,b shows the variation in the emission spectra as a function of the sample bias voltages on the HOPG and Au substrates, respectively. The arrows indicate the wavelengths of the quantum cutoff energies converted from the corresponding bias voltages. It was considered that the emission from the PTCDI-C7 thin film on the HOPG surface was excited by inelastic tunneling [31] because no polarity dependence of the STM-LE spectra was observed (data not shown), indicating that the injection-type electron-hole recombination mechanism, as in an OLED, is impossible.

Bottom Line: A fluorescence peak with vibronic progressions with large Stokes shifts was observed on both highly ordered pyrolytic graphite (HOPG) and Au substrates, indicating that the emission was derived from the isolated-molecule-like film condition with sufficient π-π interaction of the perylene rings of perylenetetracarboxylic diimide molecules.The upconversion emission mechanism of the tunneling-electron-induced emission was discussed in terms of inelastic tunneling including multiexcitation processes.The wavelength-selective enhanced emission due to a localized tip-induced surface plasmon on the Au substrate was also obtained.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Precision Science & Technology, Graduate school of Engineering, Osaka University, 2-1 Yamada-oka, Suita 565-0871, Japan. fujiki@ss.prec.eng.osaka-u.ac.jp.

ABSTRACT
We have investigated the emission properties of N,N'-diheptyl-3,4,9,10-perylenetetracarboxylic diimide thin films by the tunneling-electron-induced light emission technique. A fluorescence peak with vibronic progressions with large Stokes shifts was observed on both highly ordered pyrolytic graphite (HOPG) and Au substrates, indicating that the emission was derived from the isolated-molecule-like film condition with sufficient π-π interaction of the perylene rings of perylenetetracarboxylic diimide molecules. The upconversion emission mechanism of the tunneling-electron-induced emission was discussed in terms of inelastic tunneling including multiexcitation processes. The wavelength-selective enhanced emission due to a localized tip-induced surface plasmon on the Au substrate was also obtained.

No MeSH data available.


Related in: MedlinePlus