Ionic gel-mediated synthesis of nanostructured chiral 2D halide perovskites with amplified chiroptical response
- Do-Kyoung Lee
- Raphael F. Moral
- Finn Babbe
- Tim Kodalle
- Fabrice Roncoroni
- Harishankar Jayakumar
- Kun Zhou
- Yuanyuan Zhou
- Yen Jea Lee
- Brooks A. Abel
- Craig P. Schwartz
- Carolin M. Sutter-Fella
2026-08-29
Chiroptical properties in metal halide perovskites typically arise from asymmetric crystal structures induced by chiral organic molecules during synthesis or chiral additives. However, the synthesis of two-dimensional chiral halide perovskites with sufficiently high dissymmetry factors for practical applications remains challenging. Herein, we present a two-step ionic gel-mediated nucleation and recrystallization reaction, enabling the synthesis of nanostructured chiral halide perovskite films exhibiting large intrinsic circular dichroism dissymmetry factors ( g CD ) up to 10 −2 . The ionic gel mediates the reaction between lead(II) iodide (PbI 2 ) and R / S -methylbenzylammonium iodide ( R / S -MBAI), to facilitate the formation of higher-order iodoplumbate PbI 3 - and oligomeric Pb-I-MBA species, which recrystallize during heat treatment as anisotropic nanostructures without preferential orientation. Ionic gel-mediated films exhibit a very pronounced peak splitting originating from a well-defined exciton fine structure and narrow photoluminescence linewidth. This is indicative of the presence of electron-hole exchange interactions and minimized structural disorder in the material leading to significantly amplified chiroptical response. This work demonstrates a synthesis route for nanostructured chiral MBA 2 PbI 4 films, whose unique structural feature with reduced crystalline imperfection enables amplified circular dichroism and g CD response.