Ultrafast Charge Transfer and Coherent Phonons in Electroactive Organic Cation-Templated Low-Dimensional Perovskite Analogues

Ilan Devroey^a^,^d, Yorrick Boeije^b^,^c, Sam Stranks^b^,^c, Wouter Van Gompel^a^,^d, Peter Banks^e, David Beljonne^e

^aUHasselt – Hasselt University, Institute for Materials Research (IMO-IMOMEC), Agoralaan 1, 3590 Diepenbeek, Belgium and IMOMEC Division, IMEC, Wetenschapspark 1, 3590 Diepenbeek, Belgium

^bDepartment of Chemical Engineering & Biotechnology, University of Cambridge, Philippa Fawcett Dr, Cambridge CB3 0AS

^cCavendish Laboratory, Department of Physics, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom

^dEnergyville, imo-imomec, Thor Park 8320, B-3600, Genk, Belgium.

^eLaboratory for Chemistry of Novel Materials, University of Mons, Place du Parc 20, 7000 Mons, Belgium.

Proceedings of MATSUS Spring 2026 Conference (MATSUSSpring26)

D7 Low-Dimenisonal Halide Perovskites – Exploring Unique Challenges and Opportunities in 0D, 1D and 2D Materials

Barcelona, Spain, 2026 March 23rd - 27th

Organizers: Kunal Datta, Silvia Motti and Ajay Ram Srimath Kandada

Poster, Ilan Devroey, 827
Publication date: 15th December 2025

Hybrid organic-inorganic perovskites (HOIPs) have emerged as promising materials for optoelectronic applications, yet gaining control over their structural and electronic tunability remains a key challenge. In this study, we introduce 7H-dibenzo[c,g]carbazole (DBCz) as a novel electroactive organic cation that enables the formation of two distinct low-dimensional hybrid metal halides: a conventional 2D perovskite structure, (DBCz)₂PbI₄, and a previously unreported layered perovskite analogue structure with edge-sharing octahedra, DBCzPbI₃. The edge-sharing phase represents a new structural motif within the hybrid metal halide family. Both materials exhibit a type-II band alignment, facilitating fast photoinduced hole transfer from the inorganic to the organic layer. Using transient absorption spectroscopy, we identify the formation of DBCz-based hole polarons in both phases, and uniquely observe the charge-transfer-induced formation of triplet states and room temperature coherent phonons for the perovskite analogue phase. These findings highlight the role of molecular design in controlling excited-state dynamics and lattice interactions in hybrid metal halides.

References:

[1] Devroey, I.; Boeije, Y.; Banks, P.; Quarti, C.; La Magna, P.; Ciesielska, A.; Lutsen, L.; Derveaux, E.; Adriaensens, P.; Van Hecke, K.; et al. Ultrafast charge transfer and coherent phonons in electroactive organic cation-templated low-dimensional perovskite analogues. Nanoscale Horizons 2026, 11 (1), 185–201.

Acknowledgements:

I. D. acknowledges the Research Foundation – Flanders (FWO) for the funding of their FWO strategic basic research PhD grants (1S31325N).

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