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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: Talk
Monday, March 9, 2026, 18:30–18:45, ZEU/0255
Depth-resolved cathodoluminescence for mapping exciton diffusion in rubrene thin film polymorphs — •Heiner Thiersch1,2, Jonas Schröder1, Anna-Lena Hofmann1, Wooik Jang1, Nora Engelmann1, Fritz Henke1, Maximilian F. X. Dorfner3, Shu-Jen Wang4, Frank Ortmann3, Johannes Benduhn1,2, 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 (LD) is a key parameter in opto-electronic devices, as it governs the transport and recombination of photo-generated excitons. However, accurately measuring LD 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 LD 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 LD 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 LD characterization in semiconductors.
Keywords: Luminescence; SEM; Optoelectronics; Diffusion; Rubrene