Berlin 2024 – scientific programme
Parts | Days | Selection | Search | Updates | Downloads | Help
CPP: Fachverband Chemische Physik und Polymerphysik
CPP 18: Organic Electronics and Photovoltaics I
CPP 18.8: Talk
Tuesday, March 19, 2024, 11:45–12:00, H 0110
Charge-carrier photogeneration in single-component organic semiconductors via low excitation power triplet-triplet annihilation — •Andreas Sperlich1, Andrei Stankevych2, Rishabh Saxena2, Jeannine Grüne1,3, Stavros Athanasopoulos4, Prakhar Sahay5, Wolfgang Brütting5, Vladimir Dyakonov1, Heinz Bässler6, Anna Köhler2,6, and Andrey Kadashchuk2 — 1Experimental Physics 6, University of Würzburg, 97074 Würzburg — 2Soft Matter Optoelectronics and Bavarian Polymer Institute, University of Bayreuth, 95448 Bayreuth — 3Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, UK — 4Departamento de Física, Universidad Carlos III de Madrid, 28911 Madrid, Spain — 5Institute of Physics, University of Augsburg, 86159 Augsburg — 6Bayreuth Institute of Macromolecular Research, University of Bayreuth, 95448 Bayreuth
We investigate the carbazole-based material mCBP-CN, a typical host for TADF OLEDs. Our findings challenge established beliefs by demonstrating efficient charge-carrier generation near the absorption edge. Light-induced ESR and luminescence studies at low temperatures unveil slow carrier accumulation and recombination, indicating shallow trapping. Persistent signals in both techniques suggest a common origin. Photocurrent measurements support bimolecular charge generation, emphasizing the role of triplet-triplet annihilation in creating charge pairs. This work highlights unconventional mechanisms in organic semiconductors, relevant beyond OLEDs, but also for long-persistent luminescence, organic photovoltaics, and photocatalysis.
Keywords: Triplet-Triplet Annihilation; Photoluminescence Spectroscopy; Photo Current; ESR