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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 3: Molecular Electronics and Excited State Properties I
CPP 3.10: Vortrag
Montag, 16. März 2020, 12:00–12:15, ZEU 260
Morphological Tuning of the Dual Luminescence in Zinc-Phthalocyanine OLEDs — Sebastian Hammer1, •Thomas Ferschke1, Gabriel von Eyb1, and Jens Pflaum1,2 — 1Experimental Physics VI, Julius Maximilian University, 97074 Würzburg — 2ZAE Bayern, 97074 Würzburg
In the field of telecommunications, a rising demand for opto-electronic devices operating in the near infrared can be identified. Moreover, in order to enhance the transmission capabilities of such future photonic devices, versatile, multi-emissive materials are required.
For this purpose, we investigate the first order α-to-β phase transition and its influence on the optical properties of crystalline Zinc-Phthalocyanine (ZnPc) thin films. Under optical excitation two distinct intensity maxima are observed at 780 nm and 930 nm. The emission component around 930 nm can be assigned to excimer emission of the ZnPc α-phase [1], whereas luminescence at 780 nm originates from bulk Frenkel excitons of the corresponding β-phase. Comprehensive temperature and time dependent studies on the phase transition show the feasibility of a controllable luminescence shift of the layers. The phase transfer kinetics can be modelled by a Johnson-Mehl-Kolmogorov-Avrami model based on growth of polyhedral grains [2]. Utilizing these findings, we demonstrate the implementation of dual luminescent OLED devices based on a single ZnPc emissive layer with balanced near infrared emission.
[1]V. Kolb and J. Pflaum, Opt. Express 25, 6678 (2017)
[2]M. Avrami, J. Chem. Phys. 8, 212 (1940)