Chiral Cation Doping for Modulating Structural Symmetry of 2D Perovskites.

Xie, Yi

Morgenstein, Jack

Bobay, Benjamin G

Song, Ruyi

Caturello, Naidel AMS

Sercel, Peter C

Blum, Volker

Mitzi, David B

2023-09-01T14:28:34Z

2023-09-01T14:28:34Z

2023-08

2023-09-01T14:28:33Z

Cation mixing in two-dimensional (2D) hybrid organic-inorganic perovskite (HOIP) structures represents an important degree of freedom for modifying organic templating effects and tailoring inorganic structures. However, the limited number of known cation-mixed 2D HOIP systems generally employ a 1:1 cation ratio for stabilizing the 2D perovskite structure. Here, we demonstrate a chiral-chiral mixed-cation system wherein a controlled small amount (<10%) of chiral cation S-2-MeBA (S-2-MeBA = (S)-(-)-2-methylbutylammonium) can be doped into (S-BrMBA)₂PbI₄ (S-BrMBA = (S)-(-)-4-bromo-α-methylbenzylammonium), modulating the structural symmetry from a higher symmetry (C2) to the lowest symmetry state (P1). This structural change occurs when the concentration of S-2-MeBA, measured by solution nuclear magnetic resonance, exceeds a critical level─specifically, for 1.4 ± 0.6%, the structure remains as C2, whereas 3.9 ± 1.4% substitution induces the structure change to P1 (this structure is stable to ∼7% substitution). Atomic occupancy analysis suggests that one specific S-BrMBA cation site is preferentially substituted by S-2-MeBA in the unit cell. Density functional theory calculations indicate that the spin splitting along different k-paths can be modulated by cation doping. A true circular dichroism band at the exciton energy of the 3.9% doping phase shows polarity inversion and a ∼45 meV blue shift of the Cotton-effect-type line-shape relative to (S-BrMBA)₂PbI₄. A trend toward suppressed melting temperature with higher doping concentration is also noted. The chiral cation doping system and the associated doping-concentration-induced structural transition provide a material design strategy for modulating and enhancing those emergent properties that are sensitive to different types of symmetry breaking.

0002-7863

1520-5126

https://hdl.handle.net/10161/28917

eng

American Chemical Society (ACS)

Journal of the American Chemical Society

10.1021/jacs.3c04832

Chiral Cation Doping for Modulating Structural Symmetry of 2D Perovskites.

Journal article

Bobay, Benjamin G|0000-0003-4775-3686

Blum, Volker|0000-0001-8660-7230

Mitzi, David B|0000-0001-5189-4612

17831

17844

32

Duke

Pratt School of Engineering

School of Medicine

Trinity College of Arts & Sciences

Clinical Science Departments

Thomas Lord Department of Mechanical Engineering and Materials Science

Radiology

Chemistry

Institutes and Provost's Academic Units

University Institutes and Centers

Initiatives

Nicholas Institute for Energy, Environment & Sustainability

Nicholas Institute for Energy, Environment & Sustainability

Published

145