# Unlocking intrinsically chiral bipyrenyl-based aggregation-induced emission luminogens: circularly polarized luminescence and dynamic chirality amplification

## TL;DR

This paper introduces new chiral compounds that show strong light emission and amplified chirality when aggregated, offering insights into designing better CPL materials.

## Contribution

The paper introduces novel intrinsically chiral bipyrenyl enantiomers with dynamic chirality amplification and AIE properties.

## Key findings

- R-5 and S-5 enantiomers show high solid-state fluorescence efficiency up to 0.66.
- Amplified |gCD| values increase from 4.73 × 10−5 to 7.34 × 10−3 upon aggregation.
- Amplified chiroptical properties result from helical self-assembly and prolonged excited-state reorganization.

## Abstract

Understanding chiral dynamic mechanisms (from chirality generation and transfer, and amplification) is crucial for circularly polarized luminescent (CPL) materials. Herein, intrinsically chiral bipyrenyl-based enantiomers, R-5 and S-5, were first synthesized as model compounds to gain a deeper insight into their chiroptical properties and chirality amplification mechanisms. These enantiomers not only exhibit typical aggregation-induced emission (AIE) with a high solid-state fluorescence efficiency up to 0.66, but also display significant chirality amplification upon aggregation, with amplified |gCD| from 4.73 × 10−5 (10−7 M) to 7.34 × 10−3 (10−3 M), and |glum| values up to 4.68 × 10−4 in the solid state. Morphological and CP-fs-TA studies reveal that the amplified chiroptical properties stem from helical self-assembly and prolonged excited-state chiral conformational reorganization in aggregates. This work establishes a design strategy for high-performance CPL materials by integrating intrinsic chirality, AIE properties, and dynamic chirality amplification mechanisms.

This article presents two novel intrinsically chiral bipyrenyl-based enantiomers, R-5 and S-5, which were first synthesized as model compounds to gain a deeper insight into their chiroptical properties and chirality amplification mechanisms.