2D hybrid perovskites with tailored organic cations to tune optical and electronic properties

Wouter Van Gompel^a^,^b^,^c

^aHasselt University, Institute for Materials Research (imo-imomec), Hybrid Materials Design (HyMaD), Martelarenlaan 42, B-3500 Hasselt, Belgium.

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

^cHasselt University, Institute for Materials Research (imo-imomec), Martelarenlaan 42, B-3500 Hasselt, Belgium.

Proceedings of MATSUS Spring 2026 Conference (MATSUSSpring26)

A5 From halide perovskites to perovskite-inspired materials – Synthesis, Modelling and Application

Barcelona, Spain, 2026 March 23rd - 27th

Organizers: Gustavo de Miguel, Lorenzo Malavasi and Isabella Poli

Oral, Wouter Van Gompel, presentation 121
Publication date: 15th December 2025

Two-dimensional (2D) layered hybrid organic-inorganic perovskites (HOIPs) have emerged as promising materials for optoelectronic devices such as solar cells, LEDs, lasers, and photodetectors. Compared to their three-dimensional counterparts, 2D HOIPs offer superior environmental stability and remarkable structural tunability. Their assembly is largely dictated by the choice of organic ammonium cations, which traditionally have little direct impact on optical or electronic properties. However, incorporating electroactive cations has recently enabled hybrids with extended absorption, improved out-of-plane charge transport, and lower exciton binding energies.[1]

In 2023, we demonstrated that carbazole-based ammonium cations with varying alkyl spacer lengths (Cz-x) can tune the properties of 2D lead iodide HOIPs. Shorter spacers enhanced electronic coupling between organic and inorganic layers, and light-induced charge transfer was observed for all tested lengths (three, four, and five carbons). The shortest spacer (Cz-3) exhibited a distinct interlayer charge-transfer state and delivered the highest out-of-plane mobility, outperforming a reference system based on phenylethylammonium (PEA).[2]

Building on this, our recent work investigates how molecular design shapes the optical and electronic behavior of low-dimensional HOIPs. We compared two hybrids that share a carbazole-inspired (dibenzocarbazole) cation but differ in the connectivity of their lead iodide framework (corner vs. edge-sharing). These structural variations shift energy alignment between organic and inorganic states, altering charge-transfer dynamics and enabling new pathways.[3] In parallel, we resolved crystal structures of 2D HOIPs with pyrene-based electroactive cations and, through combined experimental-computational analysis, revealed that interlayer electronic coupling is highly sensitive to the orientation of the organic core relative to the inorganic lattice.[4]

References:

[1] Van Gompel, W.T.M.; Lutsen, L.; Vanderzande, D. 2D and quasi-2D hybrid perovskites containing organic cations with an extended conjugated system: opportunities and challenges. J. Mater. Chem. C, 2023, 11, 12877-12893.

[2] Boeije, Y.; Van Gompel, W. T. M.; Zhang, Y.; Ghosh, P.; Zelewski, S.; Maufort, A.; Roose, B.; Ying Ooi, Z.; Chowdhury, R.; Devroey, I.; Lenaers, S.; Tew, A.; Dai, L.; Dey, K.; Salway, H.; Friend, R. H.; Sirringhaus, H.; Lutsen, L.; Vanderzande, D.; Rao, A.; Stranks, S. D. Tailoring Interlayer Charge Transfer Dynamics in 2D Perovskites with Electroactive Spacer Molecules. J. Am. Chem. Soc., 2023, 145, 39, 21330-21343.

[3] Devroey, I.; Boeije, Y.; Banks, P.; Quarti, C.; La Magna, P.; Ciesielska, A.; Lutsen, L.; Derveaux, E.; Adriaensens, P.; Van Hecke, K.; Beljonne, D.; Stranks, S. D.; Van Gompel, W. T. M. Ultrafast charge transfer and coherent phonons in electroactive organic cation-templated low-dimensional perovskite analogues. Nanoscale Horiz 2025.

[4] Boeije, Y.; Lie, F.; Dubajic, M.; Garip, E.; Maufort, A.; Biega, R. I.; Lenaers, S.; Sauty, M.; Ghosh, P.; Radic, A.; Loher, A.; La Magna, P.; Salway, H.; Ashoka, A.; Chua, X. W.; Gu, Q.; Van Hecke, K.; Lutsen, L.; Vanderzande, D.; Rao, A.; Van Gompel, W. T. M.; Leppert, L.; Stranks, S. D. Molecular Engineering of Interlayer Exciton Delocalization in 2D Perovskites. J Am Chem Soc 2025, 147 (35), 31541-31557

Acknowledgements:

The Research Foundation – Flanders (FWO) is acknowledged for the funding of the research projects G0A8723N and G0AQV25N.

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