Dresden 2011 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 45: Joint Poster Session
HL 45.11: Poster
Dienstag, 15. März 2011, 18:00–21:00, P1
Single Molecule Current Sensors — •Maximilian Nothaft1, Steffen Höhla2, Fedor Jelezko1, Jens Pflaum3, and Jörg Wrachtrup1 — 13. Phys. Institut, Univ. Stuttgart, 70550 Stuttgart — 2Char of Display Technology, Univ. Stuttgart, 70550 Stuttgart — 3Exp. Phys. VI, Univ. Würzburg and ZAE Bayern, 97074 Würzburg
In this study we present our results on nanometer scale current sensing using photoluminescence quenching of single fluorescent dye molecules. From the quenching degree and internal molecular rate parameters it is possible to calculate the recombination rate and current density within the respective molecular capture radius. One striking aspect of this approach is the feasibility to optically measure the current dynamics by investigating photon correlation properties (FCS) of emitted photons.
Alterations in these properties can be directly related to time-dependent charge carrier densities. Therefore, this method enables a non-invasive determination of current densities in OLED devices at nm spatial resolution under operation.
As an example single Dibenzoterrylene dye molecules were dispersed in an OLED consisting of Poly(phenylene vinylene) (PPV) as host material. Besides determination of current density values, its spatial heterogeneity will be discussed. Additionally, a detailed analysis of current sensing sensitivity will be presented, discussing the resolution, its dependencies on internal molecular rate parameters and possible routes to further improve the measurement process.