Cristian Soncini (Author), Abhishek Kumar (Author), Federica Bondino (Author), Elena Magnano (Author), Matija Stupar (Author), Barbara Ressel (Author), Giovanni De Ninno (Author), Antonis Papadopoulos (Author), Efthymis Serpetzoglou (Author), Emmanuel Stratakis (Author), Maddalena Pedio (Author)

Abstract

In devices based on organic semiconductors, aggregation and inter-molecular interactions play a key role in affecting the photo-physical and dynamical carrier properties of the material, potentially becoming a limiting factor to achieving high efficiency. As a consequence, a detailed understanding of the interplay between the film molecular structure and the material properties is essential to properly design devices with optimized performance. Here we demonstrate how different molecular structural arrangements modulate the charge transfer (CT) dynamics in cobalt phthalocyanine (CoPc) thin films. By transient absorption spectroscopy and time-resolved photoemission spectroscopy, we study the influence of different CoPc structures on the dynamical electronic properties, the CoPc intra and inter- molecular de-excitation pathways up to 7 ns. We rationalize the ultrafast formation of triplet states in the CoPc through an electron exchange process between the single-occupied Co3dz2 orbital and p orbitals of the macrocycle, which obviate for an energetically unfavourable spin-flip. We found enhanced CT exciton lifetime in the case of the herringbone structure with respect to the brickwork one, possibly explainable by a more efficient CT exciton delocalization along the stacking axis.

Keywords

charge transfer;organic molecules;time resolved spectroscopies;

Data

Language: English
Year of publishing:
Typology: 1.01 - Original Scientific Article
Organization: UNG - University of Nova Gorica
UDC: 620.1/.2
COBISS: 157361923 Link will open in a new window
ISSN: 2050-7526
Views: 616
Downloads: 2
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Other data

Secondary title: NONE
Type (COBISS): Not categorized
Embargo end date (OpenAIRE): 2024-06-30
Pages: str. 10266-10273
Volume: ǂVol. ǂ11
Issue: ǂissue ǂ30
Chronology: 2023
DOI: 10.1039/D3TC00734K
ID: 21815636