Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

CPP: Fachverband Chemische Physik und Polymerphysik

CPP 15: Poster Session I

CPP 15.42: Poster

Montag, 17. März 2025, 19:00–21:00, P4

Thin Films of Substituted Benzo[b]fluorenes as Emitting Layers for Blue OLED Devices — •Pascal Schweitzer¹, Christopher M. Leonhardt², Cazibe Arslan¹, Hermann A. Wegner², and Derck Schlettwein¹ — ¹Justus-Liebig-Universität Gießen, Institut für Angewandte Physik, Heinrich-Buff-Ring 16, D-35392 Gießen — ²Justus-Liebig-Universität Gießen, Institut für Organische Chemie, Heinrich-Buff-Ring 17, D-35392 Gießen

Organic light emitting diodes (OLED), despite widespread application in displays, still exhibit major challenges: The search for stable and efficient blue-emitting molecules continues, as these often suffer from degradation. Here we study substituted benzo[b]fluorenes (BF) as an alternative for such emitters. Their modular structure allows for tuning opto-electronic properties. Thin films of different BF were prepared by solution-based methods or physical vapor deposition (PVD). Significant blue emission was found by photoluminescence spectroscopy in solid state. Film growth at device interfaces was studied. In-situ Kelvin-probe force microscopy (KPFM) gave insight into electrical contact formation to typical transport materials: Stranski-Krastanov growth was found in PVD onto hole-conducting poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), accompanied by the formation of an interface dipole. On the electron-conducting side, a pronounced Volmer-Weber growth of bathocuproine (BCP) on the emissive layer demands a high film thickness for pin-hole-free contacts. Finally, based on these findings, we show a working prototype of a blue OLED based on a substituted BF.

Keywords: OLED; organic semiconductor; Kelvin-Probe Force Microscopy (KPFM); thin film; photoluminescence