Phillip Greißel

Had a fantastic week of measurements at @mpip-mainz.mpg.de — thanks a lot to @giulialavarda.bsky.social for hosting me. Honored to be the first guest of her group!

Really enjoyed learning about THz spectroscopy in the group of Prof. Bonn. And many thanks to Prof. Blom for the fruitful discussions!

07.04.2025 14:31 — 👍 4    🔁 2    💬 0    📌 1

@guldi-group.bsky.social @gioben.bsky.social

19.03.2025 14:54 — 👍 1    🔁 0    💬 0    📌 0

Intramolecular Singlet Fission in Individual Graphene Nanoribbons─Competition with a Charge Transfer Graphene nanoribbons (NRs) constitute a versatile platform for developing novel materials, where their structure governs their optical, electronic, and magnetic properties while also shaping their excited-state dynamics. Here, we investigate a set of three twisted N-doped molecular NRs of increasing length, obtained by linearly fusing perylene diimide to pyrene and pyrazino- or thiadiazolo-quinoxaline residues. By employing various temperature-dependent time-resolved spectroscopy techniques, we reveal how the flexible twisted NR geometry promotes the formation of a mixed electronic state with varying contributions from locally excited and charge-transfer (CT) states. The fate of this mixed state is highly sensitive to the molecular geometry, length, and solvent polarity. For the shortest NR, intersystem crossing dominates the deactivation pathway, efficiently generating triplets in low-polarity solvents. In contrast, for the extended NRs, intramolecular singlet fission (SF) takes place within a single nanoribbon. This is enabled by enhanced superexchange coupling due to a pronounced push–pull nature and the existence of multiple localized π-electron states caused by heteroatom doping, thereby circumventing the need for dimeric interactions typically associated with conventional SF systems. In higher-polarity environments, evidence of a (diabatic) CT state emerges. These findings underscore the intricate relationship between geometry, energy levels, and excited-state dynamics in twisted N-doped NRs.

Happy to share our latest JACS publication on twisted molecular nanoribbons! Our study reveals that both external factors and ribbon length greatly influence their deactivation—longer ribbons even enable intramolecular singlet fission. Many thanks to everyone involved! pubs.acs.org/doi/10.1021/...

19.03.2025 14:54 — 👍 18    🔁 3    💬 1    📌 2

PCL — Open Positions

🚨 PhD Position Available! 🚨

Join our group at FAU as part of RTG 2861! 🎓🔬 We are looking for a PhD candidate to study carbon planar lattices via transient spectroscopies.

📌 Details & application: rtg2861-pcl.chm.tu-dresden.de/joboffer/

🔄 Retweets appreciated!

#chemsky #pisky #PhD #Spectroscopy

11.03.2025 10:43 — 👍 10    🔁 10    💬 0    📌 0

Photovoltaik: Grundlagenforschung mit hoher Relevanz Momentan verbrennen wir noch große Mengen fossiler Energieträger wie Erdöl oder Kohle, um unseren Energiehunger zu stillen. Dabei entsteht das Treibhausgas Kohlendioxid, das in der Atmosphäre wie eine...

Solarzellen der Zukunft? ☀️🔋

Die FAU-Chemiker Phillip Greißel & Dominik Thiel erforschen, wie Solarzellen noch effizienter werden können. Ihre Erkenntnisse tragen dazu bei, die nachhaltige Energiegewinnung weiter zu verbessern! 🔬⚡

Mehr dazu im Interview: www.nat.fau.de/2025/02/07/p...

10.02.2025 08:17 — 👍 5    🔁 3    💬 0    📌 0

Alright since a critical mass of photochemists officially joined it was about time to try and make a photochemistry/spectroscopy starter pack; hopefully this is a good start, feel free to reach out to be added! #chemsky

go.bsky.app/Cyibs8f

14.11.2024 03:54 — 👍 44    🔁 15    💬 24    📌 5