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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 37: Hybrid, Organic and Perovskite Optoelectronics and Photovoltaics III

CPP 37.4: Vortrag

Mittwoch, 11. März 2026, 16:00–16:15, ZEU/LICH

Probing the percolating charge transport network in organic semiconductors by noise spectroscopy — •Sebastian Klein, Priya Viji, Constantin Tormann, Clemens Göhler, and Martijn Kemerink — IMSEAM, Heidelberg University, Germany

In disordered organic semiconductors (OSCs), a suppression of shot noise is expected due to the internal charge carrier transport mechanisms, which is relevant for, e.g., their application in photodetectors. The charge transport in OSCs, which occurs by hopping between localized sites, can be described by percolation theory, from which it follows that so-called hard hops form the bottleneck that charge carriers have to overcome to progress through the device. The tunneling through one singular hard hop is a random uncorrelated poissonian process which leads to OSCs displaying shot noise. Since multiple hard hops sit in series in the charge transport path in macroscopic OSCs, it is expected that shot noise in OSC is suppressed, inversely proportional to the number of hard hops, which in turn depends on disorder, temperature and thickness of the OSC. This suppression is quantified by the Fano factor, which we directly measure by current cross-correlation noise spectroscopy. Temperature- and current-bias-dependent Fano factor measurement results are compared with kinetic Monte Carlo simulations. From the measurements and simulations, it can consistently be concluded that Fano factor measurements give direct and otherwise inaccessible insight into the internal structure as well as the disorder and correlation length of OSC.

Keywords: organic semiconductors; noise spectroscopy; Fano factor; shot noise suppression; percolation