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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 28: Poster III
CPP 28.42: Poster
Wednesday, March 20, 2024, 11:30–13:30, Poster C
Temperature Dependent Photoluminescence Studies of Metal-Free Phthalocyanine Single Crystals — •Luise Pätzold1, Lisa Schraut-May1, and Jens Pflaum1,2 — 1Experimental Physics VI, University of Würzburg, 97074 Würzburg — 2CAE Bayern, 97074 Würzburg
The opto-electronic properties of organic materials depend not only on the individual molecules, but also on their interaction in the crystalline lattice [1]. As a representative, the material class of phthalocyanines (Pc) is studied in various research fields because of the possibility to steer its opto-electronic and structural properties by choice of the central metal atom, chemical substitution of its periphery and, thus, aggregate packing [2]. This distinguishes Pc compounds to investigate the excitonic coupling between neighboring molecules under various conditions. We have grown β-phase single crystals of metal-free H2-phthalocyanine (H2-Pc) by horizontal vapor phase deposition. Polarization dependent photoluminescence (PL) measurements provide insights into the anisotropic coupling of the photoexcited molecules within the crystallographic (101) plane. Furthermore, changes in the excitonic coupling are investigated as function of temperature down to 5 K. The results will be discussed in comparison to metal-centered zinc-phthalocyanine (Zn-Pc), where a super-radiant PL enhancement is observed below 80 K which is related to a discontinuous change in inter-molecular coupling at cryogenic temperatures.
[1] Hestand et al., Chem. Rev. (2018)
[2] Rödel et al., J. Phys. Chem. C (2022)
Keywords: Excitonic Coupling; Organic Single Crystal; Micro Photoluminescence; H2-Pc; Phthalocyanine