Weise, Wieland ; Keith, Torsten ; Malm, Norwin von ; Seggern, Heinz von (2005)
Trap concentration dependence of thermally stimulated currents in small molecule organic materials.
In: Physical Review B, 72 (4)
doi: 10.1103/physRevB.72.045202
Artikel, Bibliographie
Kurzbeschreibung (Abstract)
The effect of doping of thin organic glassy films of the hole transport material N,N′-di(1-naphthyl)N,N′-diphenylbenzidine (α-NPD) with various concentrations of 4,4′, 4″-tris(N-(1-naphthyl)-N-phenylamino)-triphenylamine (1-NaphDATA) is investigated with respect to the resulting charge carrier mobility and the effect on thermally stimulated currents (TSC). The energetic trap structure is obtained utilizing the fractional TSC technique. At low doping concentrations of a few percent the activation energy of an about 0.5 eV deep trap level is measured, which is related to the higher lying highest occupied molecular orbital level of 1-NaphDATA compared to the α-NPD matrix. A strong shift of the TSC peak towards higher temperatures with increasing dopant concentration is observed. It can be attributed to re-trapping despite the low film thickness of 200 nm. Thereby the effect of re-trapping is theoretically investigated and found to be composed of a mobility change and a change of the trap depth, as it is measured in fractional TSC measurements. The latter is related to enhanced re-trapping into deeper traps. The maximal peak shift occurs at about 4 vol % of dopant concentration, corresponding to about 2.7% molecular concentration. For higher concentrations of 1-NaphDATA the mobility increases again, and the TSC peak gradually changes to that of pure 1-NaphDATA, explainable by a progressive change from a deep-trap-controlled transport to a percolating transport on the 1-NaphDATA molecules.
| Typ des Eintrags: | Artikel |
|---|---|
| Erschienen: | 2005 |
| Autor(en): | Weise, Wieland ; Keith, Torsten ; Malm, Norwin von ; Seggern, Heinz von |
| Art des Eintrags: | Bibliographie |
| Titel: | Trap concentration dependence of thermally stimulated currents in small molecule organic materials |
| Sprache: | Englisch |
| Publikationsjahr: | 6 Juli 2005 |
| Verlag: | American Physical Society |
| Titel der Zeitschrift, Zeitung oder Schriftenreihe: | Physical Review B |
| Jahrgang/Volume einer Zeitschrift: | 72 |
| (Heft-)Nummer: | 4 |
| DOI: | 10.1103/physRevB.72.045202 |
| Kurzbeschreibung (Abstract): | The effect of doping of thin organic glassy films of the hole transport material N,N′-di(1-naphthyl)N,N′-diphenylbenzidine (α-NPD) with various concentrations of 4,4′, 4″-tris(N-(1-naphthyl)-N-phenylamino)-triphenylamine (1-NaphDATA) is investigated with respect to the resulting charge carrier mobility and the effect on thermally stimulated currents (TSC). The energetic trap structure is obtained utilizing the fractional TSC technique. At low doping concentrations of a few percent the activation energy of an about 0.5 eV deep trap level is measured, which is related to the higher lying highest occupied molecular orbital level of 1-NaphDATA compared to the α-NPD matrix. A strong shift of the TSC peak towards higher temperatures with increasing dopant concentration is observed. It can be attributed to re-trapping despite the low film thickness of 200 nm. Thereby the effect of re-trapping is theoretically investigated and found to be composed of a mobility change and a change of the trap depth, as it is measured in fractional TSC measurements. The latter is related to enhanced re-trapping into deeper traps. The maximal peak shift occurs at about 4 vol % of dopant concentration, corresponding to about 2.7% molecular concentration. For higher concentrations of 1-NaphDATA the mobility increases again, and the TSC peak gradually changes to that of pure 1-NaphDATA, explainable by a progressive change from a deep-trap-controlled transport to a percolating transport on the 1-NaphDATA molecules. |
| Zusätzliche Informationen: | SFB 595 D4 |
| Fachbereich(e)/-gebiet(e): | 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft > Elektronische Materialeigenschaften Zentrale Einrichtungen DFG-Sonderforschungsbereiche (inkl. Transregio) > Sonderforschungsbereiche > SFB 595: Elektrische Ermüdung DFG-Sonderforschungsbereiche (inkl. Transregio) > Sonderforschungsbereiche > SFB 595: Elektrische Ermüdung > D - Bauteileigenschaften DFG-Sonderforschungsbereiche (inkl. Transregio) > Sonderforschungsbereiche > SFB 595: Elektrische Ermüdung > D - Bauteileigenschaften > Teilprojekt D4: Betriebsbedingte Ermüdung von Bauelementen aus organischen Halbleitern 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft 11 Fachbereich Material- und Geowissenschaften DFG-Sonderforschungsbereiche (inkl. Transregio) > Sonderforschungsbereiche DFG-Sonderforschungsbereiche (inkl. Transregio) |
| Hinterlegungsdatum: | 16 Sep 2011 14:00 |
| Letzte Änderung: | 17 Feb 2016 12:26 |
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