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Hybrid structures with an interface between two different materials with properly aligned energy levels facilitate photo-induced charge separation to be exploited in opto- electronic applications. Particularly, the combination of 2D transition metal dichalco- genides (TMDCs) and dye molecules offers strong light-matter interactions, tailorable band level alignments, and high fluorescence quantum yields. In this work, we aim at the charge transfer-related quenching of the fluorescence of the dye perylene orange (PO) when coated onto 2D materials. To that end, we established multiple techniques for monomer deposition, proposing a stamping approach as a solution-based entry into the preparation of hybrid structures for the 2D community and thermal vapor deposition (TVD) as a vacuum-based method particularly suited for homogenous films in the sub-monolayer regime. In the latter case, scanning force microscopy reveals an increased step-height compared to pristine flakes, suggesting that PO creeps into the interface below the flake. Via TVD, we prepare hybrid structures of PO on monolayer TMDCs and hexagonal boron nitride (hBN) as a reference. Micro-photoluminescence spectroscopy indicates monomer behavior of the PO on both substrate and on hBN flakes, while on the TMDC surface, the fluorescence is quenched. This is further confirmed by fluorescence lifetime imaging microscopy, additionally providing information on the emission decay. In line with the drastic intensity drop by up to a factor of 103 compared to the hBN reference, a reduction of the fluorescence lifetime is observed, from 3 ns to values well below 100 ps. From the ratio of the intensity quenching that is attributed to charge transfer from dye to semiconductor, we deduce a transfer time of several picoseconds, pointing to an efficient charge separation suitable for optoelectronic devices.

Rights:

• cc-by-nc-3.0
  

Keyword: Charge separation, transition metal dichalcogenides, dye molecules

Date published: 2023-05-22

Publisher: Royal Society of Chemistry (RSC)

Journal:

• Nanoscale Advances (ISSN: 25160230) vol. 5 issue. 12 p. 3348-3356

Funding:

• Deutsche Forschungsgemeinschaft SFB 1477 / 441234705
• Deutsche Forschungsgemeinschaft KO 3612/7-1 / 467549803
• Universität Rostock
• Japan Society for the Promotion of Science 23H02052
• Japan Society for the Promotion of Science 20H00354

Manuscript type: Publisher's version (Version of record)

MDR DOI:

First published URL: https://doi.org/10.1039/d3na00276d

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Updated at: 2025-02-15 12:30:38 +0900

Published on MDR: 2025-02-15 12:30:38 +0900