SKM 2023 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 19: Organic Electronics and Photovoltaics I (joint session CPP/HL)

HL 19.7: Talk

Tuesday, March 28, 2023, 11:00–11:15, GÖR 226

Noise in Organics Semiconductors and Devices — •Priya Viji, Dorothea Scheunemann, Constantin Tormann, and Martijn Kemerink — Institute for Molecular Systems Engineering and Advanced Materials, Heidelberg University, Germany

Noise, typically considered an unwanted signal in measurements, can also contain information about the charge kinetics in organic semiconductors. Since the corresponding devices often show high resistances and capacitances, the measurement of -albeit very small- current fluctuations via voltage noise is most suitable. To quantify this noise and to eliminate noise from other devices in the measurement line, a cross-correlation technique is implemented and applied to P3HT doped with varying concentrations of F4TCNQ. The results compare quantitatively with kinetic Monte Carlo simulations in which noise calculations were implemented. To understand the effect of the electric field on the charge carriers, disentangling noise in directions parallel and perpendicular to the electric field is essential. The direction perpendicular to the electric field does show a gradual increase at high electric fields, which matches the concept of an Effective Temperature, as described by Marianer and Shklovskii, in which the effects of electric field and lattice temperature are combined. In the direction of the electric field, an additional contribution due to shot noise is observed. However, its magnitude deviates from the theoretical prediction of shot noise, which can be quantified as a non-unity Fano-factor.