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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 39: Focus Session: Ultrafast Processes in Organic Semiconductors and Perovskites I (joint session O/CPP)

CPP 39.6: Talk

Thursday, March 21, 2024, 12:15–12:30, MA 004

Ultrafast charge separation and band structure dynamics in metal-phthalocyanine/WSe₂ heterostructures — •Gregor Zinke, Sebastian Hedwig, Benito Arnoldi, Martin Anstett, Martin Aeschlimann, and Benjamin Stadtmüller — University of Kaiserslautern-Landau, Germany

2D-Van-der-Waals materials and their heterostructures are a highly promising class of materials due to their low dimensional nature and diverse electronic properties, especially regarding their charge and spin carrier dynamics. In addition to chemical tunability, the spin-dependent electronic properties of such 2D heterostructures can also be altered on ultrafast timescales by the formation of transient charge-separated states. In this contribution, we focus on optically induced interlayer charge and spin transfer processes in heterostructures consisting of molecule films on the surface of a bulk WSe₂ crystal. Using spin-, time- and angle-resolved photoemission with XUV radiation, we can simultaneously monitor the excited carriers as well as the corresponding hole dynamics. For molecule films made of the metal phthalocyanines (MPcs) CuPc and FePc, we discuss the temporal evolution of optically excited spin and charge carriers in these MPc /WSe₂ heterostructures. We will illustrate the influence of the distinct orbital character of the central metal atom and structural order of the MPc molecules on the ultrafast electron and hole dynamics at the MPc/WSe₂ interface and discuss their impact on the transient changes in the interfacial energy level alignment.

Keywords: WSe2; interface dynamics; photoemission; molecular heterostructure; excitons