Controlling Phase Purity in Chiral 2D Perovskites

Lucas Scalon^a^,^b, Julius Brunner^b, Caio Costa Oliveira^a, Ana Flávia Nogueira^a, Yana Vaynzof^b

^aInstitute of Chemistry, University of Campinas – UNICAMP, Campinas, SP, Brazil. Fax: 55 19 3521 3023; Tel: 55 19 3521 3029, Brazil

^bCenter For Advancing Electronics Dresden (cfaed), TU Dresden, Helmholtzstraße 18, 01089 Dresden, Germany

Materials for Sustainable Development Conference (MATSUS)
Proceedings of MATSUS23 & Sustainable Technology Forum València (STECH23) (MATSUS23)

#2DPERO - 2D Perovskites: Synthesis, Properties, and Applications

VALÈNCIA, Spain, 2023 March 6th - 10th

Organizers: Simon Kahmann and Loreta Muscarella

Oral, Lucas Scalon, presentation 283
DOI: https://doi.org/10.29363/nanoge.matsus.2023.283
Publication date: 22nd December 2022

The introduction of chiral organic spacers in 2D and 1D perovskites breaks the inversion symmetry operation in the crystal, due to the asymmetric hydrogen bonding between the H atom of the ammonium group in the organic cation and the halide atom (Cl, Br, or I) in the lead octahedra. [1,2] The absence of inversion symmetry operation results in the emergence of Rashba/Dresselhaus spin-splitting, i.e. the splitting of the double degenerated electronic band into two bands with the same energy, but shifted in k-space,[3,4] triggering spin-dependent properties even in the absence of magnetic field. Such a feature has been utilized for applications in polarized light detectors,[5] spin-dependent charge transport,[6] and polarized light-emitting diodes.[7] In this work, we investigate how the processing of chiral 2D perovskites impacts their optical properties, microstructure, and phase purity. Specifically, we synthesized the R-, S-, and rac-MBA2PbI4 (MBA: methylbenzylammonium) and varied the solvent used for film deposition (dimethylformamide, DMF, or acetonitrile, ACN), and the subsequent thermal annealing procedure. We found that the processing conditions strongly impact the optical properties and microstructure of the chiral 2D perovskites. Moreover, we identified the anisotropic emergence of a 1D phase, which is dependent on the molecule's chirality and seems more prone to occur with pure enantiomers than in the racemic mixture. We demonstrate that its formation is suppressed when the 2D perovskite is processed from DMF, due to its higher boiling point and a stronger interaction between the solvent and Pb2+ ions, thus enabling a higher phase purity. These observations give fundamental insights into the film formation processes of chiral 2D perovskites and offer processing strategies to control anisotropic growth in 2D perovskite and to tune their chiroptical response.

References:

[1] M. K. Jana, R. Song, H. Liu, D. R. Khanal, S. M. Janke, R. Zhao, C. Liu, Z. Valy Vardeny, V. Blum, D. B. Mitzi, Organic-to-inorganic structural chirality transfer in a 2D hybrid perovskite and impact on Rashba-Dresselhaus spin-orbit coupling. Nat. Commun. 11, 4699 (2020).

[2] M. K. Jana, R. Song, Y. Xie, R. Zhao, P. C. Sercel, V. Blum, D. B. Mitzi, Structural descriptor for enhanced spin-splitting in 2D hybrid perovskites. Nat. Commun. 12, 4982 (2021).

[3] D. Niesner, M. Wilhelm, I. Levchuk, A. Osvet, S. Shrestha, M. Batentschuk, C. Brabec, T. Fauster, Giant Rashba Splitting in CH_{3}NH_{3}PbBr_{3} Organic-Inorganic Perovskite. Phys. Rev. Lett. 117, 126401 (2016).

[4] M. Kepenekian, J. Even, Rashba and Dresselhaus Couplings in Halide Perovskites: Accomplishments and Opportunities for Spintronics and Spin-Orbitronics. J. Phys. Chem. Lett. 8, 3362–3370 (2017).

[5] C. Chen, L. Gao, W. Gao, C. Ge, X. Du, Z. Li, Y. Yang, G. Niu, J. Tang, Circularly polarized light detection using chiral hybrid perovskite. Nat. Commun. 10, 1927 (2019).

[6] H. Lu, J. Wang, C. Xiao, X. Pan, X. Chen, R. Brunecky, J. J. Berry, K. Zhu, M. C. Beard, Z. V. Vardeny, Spin-dependent charge transport through 2D chiral hybrid lead-iodide perovskites. Sci. Adv. 5, eaay0571 (2019).

[7] Y.-H. Kim, Y. Zhai, H. Lu, X. Pan, C. Xiao, E. A. Gaulding, S. P. Harvey, J. J. Berry, Z. V. Vardeny, J. M. Luther, M. C. Beard, Chiral-induced spin selectivity enables a room-temperature spin light-emitting diode. Science. 371, 1129–1133 (2021).

Acknowledgements:

L.S., and A.F.N gratefully acknowledges support from FAPESP (São Paulo Research Foundation, Grant Numbers 2017/11631-2 and 2018/21401-7), Shell, and the strategic importance of the support given by ANP (Brazil’s National Oil, Natural Gas, and Biofuels Agency) through the R&D levy regulation. L.S. acknowledges FAPESP (grants 2020/04406-5, and 2021/12104-1). C.C.O. acknowledges FAPESP (grants 2018/01669-5 and 2014/25770-6). We also thank the National Council for Scientific and Technological Development (CNPq) and the Center for Innovation on New Energies (CINE). Y.V. and J.B. thanks the Deutsche Forschungsgemeinschaft (DFG) for funding in the framework of the Special Priority Program (SPP 2196) project PERFECT PVs (#424216076).

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