Chiral supramolecular assemblies for high-performance circularly polarized electroluminescence: from chiral amplification to device engineering.

Abstract

Circularly polarized electroluminescence (CP-EL) is regarded as a pivotal optoelectronic technology for three-dimensional displays, chiral encryption, and spin photonic devices. However, the construction of chiral emitters that simultaneously achieve a large asymmetry factor (glum) value and high electroluminescence efficiency remains a great challenge, serving as the primary bottleneck limiting the practical deployment of CP-EL devices. As an effective and straightforward technique, supramolecular assembly relies on weak noncovalent interactions to construct ordered chiral aggregates, offering a feasible way to overcome the inherently low glum values of conventional chiral emitters. In the past few years, supramolecular CP-EL systems, including chiral host-guest co-assembly, chiral liquid crystal (LC) assembly, and biomimetic hierarchical structure construction, have been extensively developed. Benefiting from optimized processing technologies such as interfacial regulation and vacuum deposition, many assembled films exhibit enhanced chiral amplification and electroluminescence performance. Nevertheless, there are still some problems for chiral supramolecular assembly CP-EL emitters, such as poor host-guest compatibility and prone phase separation, which restrict their practical applications to a certain extent. Herein, we systematically recapitulate recent advances in supramolecular CP-EL, critically examining the underlying assembly mechanisms and their correlation with device performance. Furthermore, we propose remaining challenges and highlight promising directions for future inquiry, emphasizing in situ characterization techniques, multi-scale structural engineering, and the design of next-generation chiral emitters.