Low-Dimensional Azetidinium Pb-free Perovskite Derivatives

Young Un Jin^a, Bernd Marler^b, Andrei N. Salak^c, Marianela Escobar-Castillo^a, Witchaya Arpavate^a, Shaista Tahir^a, Lars Leander Schaberg^d, Niels Benson^d, Doru C. Lupascu^a

^aInstitute for Materials Science and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, 45141 Essen, Germany

^bInstitute of Geology, Mineralogy and Geophysics, Ruhr-University Bochum, 44780 Bochum, Germany

^cDepartment of Materials and Ceramics Engineering, CICECO-Aveiro Institute of Materials, University of Aveiro, 3810-193 Aveiro, Portugal

^dInstitute of Technology for Nanostructures (NST), University of Duisburg-Essen, 47057 Duisburg, Germany

Proceedings of Perovskite Semiconductors: From Fundamental Properties to Devices (PerFunPro)

Konstanz, Germany, 2025 September 8th - 10th

Organizers: Lukas Schmidt-Mende, Vladimir Dyakonov and Selina Olthof

Poster, Young Un Jin, 037
Publication date: 16th July 2025

Organic-inorganic hybrid halide perovskites (OIHPs) have emerged as next-generation materials for photovoltaic and optoelectronic applications, owing to their high absorption coefficients, suitable bandgaps, and excellent electronic properties.[1,2] However, several challenges must be addressed for commercialization. The reliance on lead (Pb) is essential for achieving a high power conversion efficiency. In addition, these materials are prone to decomposition under moisture, heat, and light. Therefore, the design of novel Pb-free hybrid halides is of high interest.

We have identified azetidinium (C₃H₈N⁺, Az⁺) as a promising organic cation for the A-site in OIHPs, due to its similar effective radius to methylammonium and formamidinium.[3] Despite this, Az⁺ has been rarely explored in OIHPs. Here, we present seven newly synthesized, Pb-free, low-dimensional azetidinium metal halides comprising 0D, 1D, and 2D structures at the molecular level: (Az)₂AgBiBr₆, (Az)₃Bi₂I₉, (Az)₃Bi₂Br₉, (Az)₃Bi₂Cl₉, (Az)₃Sb₂I₉, (Az)₃Sb₂Br₉, and (Az)₃Sb₂Cl₉.[4,5,6] These materials commonly exhibit excitonic features in their optical absorption spectra, indicating potential for tandem photovoltaics and luminescent applications. Additionally, we investigate the behavior of the azetidinium molecules and phase transitions at low temperatures.

References:

[1] Kojima, A.; Teshima, K.; Shirai, Y.; Miyasaka, T. Organometal Halide Perovskites as Visible-Light Sensitizers for Photovoltaic Cells. J. Am. Chem. Soc. 2009, 131, 6050−6051.

[2] Jena, A. K.; Kulkarni, A.; Miyasaka, T. Halide Perovskite Photovoltaics: Background, Status, and Future Prospects. Chem. Rev. 2019, 119, 3036−3103.

[3] Kieslich, G.; Sun, S.; Cheetham, A. K.Solid-state principles applied to organic–inorganic perovskites: new tricks for an old dog. Chem. Sci. 2014, 5, 4712–4715.

[4] Jin, Y. U.; Marler, B.; Karabanov, A. D.; Winkler, K.;Yap, I. C. J.; Dubey, A.; Spee, L.; Castillo, M. E.; Muckel, F.; Salak, A. N.; Benson, N.; Lupascu, Lead-free organic–inorganic azetidinium alternating metal cation bromide: [(CH2)3NH2]2AgBiBr6, a perovskite-related absorber. D. C. RSC Adv. 2023, 13, 36079–36087.

[5] Jin, Y. U.; Marler, B.; Salak, A. N.; Castillo, M. E.; Benson, N.; Lupascu, D. C. Perovskite-inspired low-dimensional hybrid azetidinium bismuth halides: [(CH2)3NH2]3Bi2X9 (X = I, Br, Cl). Mater. Chem. Front., 2025, 9, 1002-1012.

[6] Jin, Y. U.; Marler, B.; Salak, A. N.; Castillo, M. E.; Benson, N.; Lupascu, D. C. Low-dimensional hybrid lead-free azetidinium metal halides. MRS Commun., 2025, in press.

Acknowledgements:

Doru C. Lupascu, Niels Benson, Shaista Tahir, Lars Leander Schaberg, and Young Un Jin acknowledge funding through the German Science Foundation (Deutsche Forschungsgemeinschaft, DFG) under project number 424708448. Andrei N. Salak acknowledges his individual grant 2023.06320.CEECIND/CP2840/CT0003, as well as the support of the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020, UIDP/50011/2020 & LA/P/0006/2020, financed by national funds through the FCT/MEC (PID-DAC). Witchaya Arpavate acknowledges the support of the Thai Government (Government Science and Technology Scholarship). The authors acknowledge Erik Elkaïm, Antoine Barbier, and Pierre Fertey for assistance during the experiments 20230500 and 20240535 carried out at beamline CRISTAL at SOLEIL. The experiment at SOLEIL has been co-funded by the project NEPHEWS under Grant Agreement No. 101131414 from the EU Framework Programme for Research and Innovation Horizon Europe.

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