Year: 2024
Type: article
Abstract: Two‐dimensional (2D) chiral hybrid perovskites A 2 PbI 4 (A: chiral organic ion) enable chirality controlled optoelectronic and spin‐based properties. A + organic sublattice induces chirality into the semiconducting [PbI 4 ] 2− inorganic sublattice through non‐covalent interactions at organic–inorganic interface. Often, the A + cations in the lattice have different orientations, leading to asymmetry in the non‐covalent interactions. In a novel approach, we use different conformers of A + cations to create asymmetry in the non‐covalent interactions, thereby, achieving chiral perovskites with rare helical enantiomorphic structures. We prepared ( R ‐IdPA) 2 PbI 4 and ( S ‐IdPA) 2 PbI 4 (IdPA: 1‐iodopropan‐2‐ammonium) which crystallize in the helical enantiomorphic space groups P4 3 2 1 2 and P4 1 2 1 2, respectively. The gauche‐ and anti‐conformers of IdPA + are arranged alternatively in the hybrid structure. Importantly, the anti‐conformer of IdPA + ion have significantly stronger electrostatic, N−H⋅⋅⋅I hydrogen bonding, and I⋅⋅⋅I halogen bonding interactions with the [PbI 4 ] 2− sublattice, compared to the gauche‐conformer. This periodic asymmetry in non‐covalent interactions caused by the alternative arrangement of gauche‐ and anti‐conformers induces chirality in the inorganic sublattice with four‐fold screw axes (4 3 and 4 1 ). The enantiomers ( R ‐/ S ‐IdPA) 2 PbI 4 show mirror‐image like circular dichroism from excitonic absorption of the inorganic sublattice. This conformer‐based design of chiral hybrid perovskites in helical space groups broadens material choices for advanced optoelectronic applications.
Authors: Taniya Dutta, Diptikanta Swain, Angshuman Nag
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W4405706120