Control of crystal symmetry breaking with halogen substituted benzylammonium in layered hybrid metal-halide perovskites

Tanja Schmitt (1, 2) , Sean Bourelle (1) , Nathaniel Tye (1) , Giancarlo Soavi (1, 3) , Andrew D Bond (1) , Sascha Feldmann (1) , Boubacar Traoré (4) , Claudine Katan (4) , Jacky Even (5) , Siân Dutton (1) , Felix Deschler (1, 6)

1 CAM - University of Cambridge [UK]
2 Universität Heidelberg
3 Friedrich-Schiller-Universität = Friedrich Schiller University Jena [Jena, Germany]
4 ISCR - Institut des Sciences Chimiques de Rennes
5 FOTON - Institut des Fonctions Optiques pour les Technologies de l'informatiON
6 TUM - Technische Universität Munchen - Technical University Munich - Université Technique de Munich

Layered hybrid metal-halide perovskites with non-centrosymmetric crystal structure are predicted to show spin-selective band splitting from Rashba effects. Thus, fabrication of metal-halide perovskites with defined crystal symmetry is desired to control the spin-splitting in their electronic states. Here, we report the influence of halogen para-substituents on the crystal structure of benzylammonium lead iodide perovskites (4-XC6H4CH2NH3)2PbI4 (X = H, F, Cl, Br). Using X-ray diffraction and second-harmonic generation, we study structure and symmetry of single crystal and thin film samples. We report that introduction of a halogen atom lowers the crystal symmetry such that the chlorine- and bromine-substituted structures are non-centrosymmetric. The differences can be attributed to the nature of the intermolecular interactions between the organic molecules. We calculate electronic band structures and find good control of Rashba splittings. Our results present a facile approach to tailor hybrid layered metal halide perovskites with potential for spintronic and non-linear optical applications.

Domaines: Chimie; Physique [physics]

Tanja Schmitt, Sean Bourelle, Nathaniel Tye, Giancarlo Soavi, Andrew D Bond, et al.. Control of crystal symmetry breaking with halogen substituted benzylammonium in layered hybrid metal-halide perovskites. Journal of the American Chemical Society, 2020, 142 (11), pp.5060-5067. ⟨10.1021/jacs.9b11809⟩. ⟨hal-02492646⟩