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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 28: Poster III
CPP 28.21: Poster
Mittwoch, 20. März 2024, 11:30–13:30, Poster C
Design and fabrication of blue TADF OLEDs based on ν-DABNA emitter — •Ahmed Mohamed, Mona Löther, Felix Kübert, Johannes Leser, Vladimir Dyakonov, and Andreas Sperlich — Experimental Physics 6, Julius-Maximilians-Universität Würzburg, 97074 Würzburg, Germany
Fabrication of efficient blue organic light emitting diodes (OLEDs) is the key challenge for OLED displays. The 2nd generation blue Phosphorescence OLEDs (PHOLED) still show low stability and have the requirements of heavy metals. Thermally activated delayed fluorescence (TADF) is considered a promising alternative of the PHOLED due to the 100% internal quantum efficiency. This study includes the design of a blue TADF OLED with the following structure [Glass/ITO/NPD /TCTA /mCP /mCBP:ν-DABNA /TSPO1 /LiF/Al]. The device was fabricated using a self-built semi-automated thermal evaporation machine with 6 sources in the organic chamber and 2 sources in the metal chamber. The thickness and surface roughness of all the organic and metallic layers were characterized using a thickness profilometer (DEKTAK) and atomic force microscope (AFM). The tooling factors of the quartz crystal monitors was calibrated by measuring the actual thickness of each layer separately. OLED efficiency is characterized by measuring the current-voltage-luminance (IVL), the current efficiency (cd/A), and emission spectra. Long-term stability of OLEDs were investigated. Optimization of layers thickness and surface roughness leads to further improvements on the stability and efficiency of OLEDs.
Keywords: OLED; TADF; deep blue; Atomic force microscope (AFM)