Limits...
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.


Related in: MedlinePlus

STM topographic images and photon integration maps of PTCDI-C7 thin films. STM topographic images on (a) HOPG and (c) Au substrates, and photon integration maps on (b) HOPG and (d) Au substrates. Pairs of a topographic image and a photon map ((a) and (c), (b) and (d)) were obtained simultaneously (Vs = +2.2 V, It = 20 nA).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3211436&req=5

Figure 1: STM topographic images and photon integration maps of PTCDI-C7 thin films. STM topographic images on (a) HOPG and (c) Au substrates, and photon integration maps on (b) HOPG and (d) Au substrates. Pairs of a topographic image and a photon map ((a) and (c), (b) and (d)) were obtained simultaneously (Vs = +2.2 V, It = 20 nA).

Mentions: Figure 1a,c shows STM topographic images of the PTCDI-C7 thin films on the HOPG and Au substrates, and Figure 1b,d shows photon intensity maps corresponding to the STM images in Figure 1a,c, respectively. These pairs of topographic and photon images were obtained simultaneously in the constant-current mode. The surface roughnesses of the molecular films in Figure 1a,c were induced by the surface morphologies of the pristine substrates: The surface of the HOPG substrate was atomically flat and that of the as-deposited Au substrate showed a relatively large corrugation. In both the substrates, it was found that the molecules are not well crystallized but show an amorphous behavior. Homogeneous emissions were observed from the entire scanned area in both Figure 1b,d, so that homogeneous and smooth PTCDI-C7 thin films were formed on both the substrates, which showed a good correspondence of the STM topographic images. In the STM-LE measurement in this study, the tip was placed in contact with the thin film under our high-current condition; as a result, the tips might have swept molecules during the scan, in which tunneling electrons directly passed through the thin film to the substrate without an air gap between the tip and the sample.


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)

STM topographic images and photon integration maps of PTCDI-C7 thin films. STM topographic images on (a) HOPG and (c) Au substrates, and photon integration maps on (b) HOPG and (d) Au substrates. Pairs of a topographic image and a photon map ((a) and (c), (b) and (d)) were obtained simultaneously (Vs = +2.2 V, It = 20 nA).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 1: STM topographic images and photon integration maps of PTCDI-C7 thin films. STM topographic images on (a) HOPG and (c) Au substrates, and photon integration maps on (b) HOPG and (d) Au substrates. Pairs of a topographic image and a photon map ((a) and (c), (b) and (d)) were obtained simultaneously (Vs = +2.2 V, It = 20 nA).
Mentions: Figure 1a,c shows STM topographic images of the PTCDI-C7 thin films on the HOPG and Au substrates, and Figure 1b,d shows photon intensity maps corresponding to the STM images in Figure 1a,c, respectively. These pairs of topographic and photon images were obtained simultaneously in the constant-current mode. The surface roughnesses of the molecular films in Figure 1a,c were induced by the surface morphologies of the pristine substrates: The surface of the HOPG substrate was atomically flat and that of the as-deposited Au substrate showed a relatively large corrugation. In both the substrates, it was found that the molecules are not well crystallized but show an amorphous behavior. Homogeneous emissions were observed from the entire scanned area in both Figure 1b,d, so that homogeneous and smooth PTCDI-C7 thin films were formed on both the substrates, which showed a good correspondence of the STM topographic images. In the STM-LE measurement in this study, the tip was placed in contact with the thin film under our high-current condition; as a result, the tips might have swept molecules during the scan, in which tunneling electrons directly passed through the thin film to the substrate without an air gap between the tip and the sample.

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