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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 10: Electrical, Dielectrical and Optical Properties of Thin Films
CPP 10.4: Talk
Monday, March 18, 2024, 15:45–16:00, H 0111
Emission characteristics of thermally evaporated Zinc Phthalocyanine molecules in a Tetratetracontane matrix — •Gunilla W. Harm1, Uta Schlickum2, and Tobias Voss1 — 1Institute of Semiconductor Technology, Technische Universität Braunschweig, Braunschweig, Germany — 2Institute of Applied Physics, Technische Universität Braunschweig, Braunschweig, Germany
Due to their chemical and thermal stability, Phthalocyanine molecules are promising candidates for the use as molecular quantum emitters. To investigate their potential for optoelectronic devices, we studied the emission characteristics of thermally evaporated Zinc Phthalocyanine (ZnPc) molecules on semiconductor surfaces, such as GaN. When in a crystalline phase, intermolecular coupling can influence their optical properties. To reduce this effect, the molecules are diluted by embedding them into a matrix formed by the alkane Tetratetracontane (TTC). Our results indicate that the thickness of the ZnPc film, ranging from multilayers to sub-monolayers, affects the excitonic coupling between the ZnPc molecules. The absorption band between 690 nm to 800 nm shows a reduced intensity with decreasing thickness. In addition to the typical emission in the NIR range, we see another emission band around 675 nm, which is similar to that of molecules in solution. This allows us to control the intensity ratio between the two emission bands by changing the film thickness of the ZnPc in TTC.
Keywords: Time-integrated Photoluminescence; Excitonic Coupling; Crystall Phase Transition