Ligand-mediate exciton allocation enables efficient cluster-based white light-emitting diodes via single and heavy doping.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 38866737.
- Also identified by DOI 10.1038/s41467-024-49394-8 and PMC identifier 11169358.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Despite potential in high-resolution and low-cost displays and lighting, multi-doping structures and low concentrations (<1%) limit repeatability and stability of single-emissive-layer white light-emitting devices. Herein, we report a singly doped white-emitting system of blue thermally activated delayed fluorescence host matrix (CzAcSF) doped by yellow Cu<sub>4</sub>I<sub>4</sub> cluster ([tBCzDppy]<sub>2</sub>Cu<sub>4</sub>I<sub>4</sub>). CzAcSF:x% [tBCzDppy]<sub>2</sub>Cu<sub>4</sub>I<sub>4</sub> films realize photo- and electro-luminescence colors from cool white to warm white at x = 20-40. The external quantum efficiency of 23.5% was achieved at x = 30, indicating the record-high efficiency among solution-processed analogs and the largest doping concentration among efficient white light-emitting devices. It shows that di(tert-butyl)carbazole moieties in [tBCzDppy]<sub>2</sub>Cu<sub>4</sub>I<sub>4</sub> provide high-lying excited energy levels at~2.6 eV to mediate energy transfer from CzAcSF (2.9 eV) to coordinated Cu<sub>4</sub>I<sub>4</sub> (2.2 eV). Our results demonstrate the antenna effect of ligands on optimizing charge and energy transfer in organic-cluster systems and superiority of white cluster light-emitting diodes in practical applications.