High-Efficiency Circularly Polarized Light-Emitting Diodes Based on Chiral Metal Nanoclusters

Abstract
Circularly polarized light-emitting diodes (CP-LEDs) are critical for next-generation optical technologies, ranging from holography to quantum information processing. Currently deployed chiral luminescent materials, with their intricate synthesis and processing and limited efficiency, are the main bottleneck for CP-LEDs. Chiral metal nanoclusters (MNCs) are potential CP-LED materials, given their ease of synthesis and processability as well as diverse structures and excited states. However, their films are usually plagued by inferior electronic quality and aggregation-caused photoluminescence quenching, necessitating their incorporation into host materials; without such a scheme, MNC-based LEDs exhibit external quantum efficiencies (EQEs) < 10%. Herein, we achieve an efficiency leap for both CP-LEDs and cluster-based LEDs by using novel chiral MNCs with aggregation-induced emission enhancement. CP-LEDs using enantiopure MNC films attain EQEs of up to 23.5%. Furthermore, by incorporating host materials, the devices yield record EQEs of up to 36.5% for both CP-LEDs and cluster-based LEDs, along with electroluminescence dissymmetry factors (|gEL|) of around 1.0 × 10–3. These findings open a new avenue for advancing chiral light sources for next-generation optoelectronics.

Acknowledgements
This work received financial support from the King Abdullah University of Science and Technology (KAUST). The authors also thank the Supercomputing Laboratory at KAUST for the computational resources. B.S. acknowledges the support from the China Scholarship Council (No. 202006070004).

Publisher
American Chemical Society (ACS)

Journal
Journal of the American Chemical Society

DOI
10.1021/jacs.3c13065

Additional Links
https://pubs.acs.org/doi/10.1021/jacs.3c13065