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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 15: Emerging Topics in Chemical and Polymer Physics, New Instruments and Methods II

CPP 15.6: Vortrag

Montag, 9. März 2026, 18:30–18:45, ZEU/0255

Depth-resolved cathodoluminescence for mapping exciton diffusion in rubrene thin film polymorphs — •Heiner Thiersch^1,2, Jonas Schröder¹, Anna-Lena Hofmann¹, Wooik Jang¹, Nora Engelmann¹, Fritz Henke¹, Maximilian F. X. Dorfner³, Shu-Jen Wang⁴, Frank Ortmann³, Johannes Benduhn^1,2, Ellen Hieckmann¹, and Karl Leo¹ — ¹IAPP, TU Dresden, Germany — ²DZA Görlitz, Germany — ³Dep. of. Chem., TU München, Germany — ⁴Dep. of. Phys., HKBU, China

The exciton diffusion length (L_D) is a key parameter in opto-electronic devices, as it governs the transport and recombination of photo-generated excitons. However, accurately measuring L_D remains challenging due to the limited penetration depth and lateral resolution of conventional techniques such as photoluminescence quenching and transient absorption spectroscopy. Here, we will introduce a novel approach for L_D determination based on quenching processes observed by depth-resolved cathodoluminescence (CL) measurements with highly localized excitation. The method combines CL experiments with kinetic Monte Carlo simulations and a diffusion model derived from Fick’s second law. Applied to the organic semiconductor rubrene- renowned for its high hole mobility in single crystals- the technique yields L_D values ranging from 50 to 100 nm across different thin-film polymorphs. The results provide new insights into the exciton dynamics of rubrene and present a new methodological tool for accurate L_D characterization in semiconductors.

Keywords: Luminescence; SEM; Optoelectronics; Diffusion; Rubrene