Efficient deep-blue electroluminescence from Ce-based metal halide.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 39048553.
- Also identified by DOI 10.1038/s41467-024-50508-5 and PMC identifier 11269580.
- 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
Rare earth ions with d-f transitions (Ce<sup>3+</sup>, Eu<sup>2+</sup>) have emerged as promising candidates for electroluminescence applications due to their abundant emission spectra, high light conversion efficiency, and excellent stability. However, directly injecting charge into 4f orbitals remains a significant challenge, resulting in unsatisfied external quantum efficiency and high operating voltage in rare earth light-emitting diodes. Herein, we propose a scheme to solve the difficulty by utilizing the energy transfer process. X-ray photoelectron spectroscopy and transient absorption spectra suggest that the Cs<sub>3</sub>CeI<sub>6</sub> luminescence process is primarily driven by the energy transfer from the I<sub>2</sub>-based self-trapped exciton to the Ce-based Frenkel exciton. Furthermore, energy transfer efficiency is largely improved by enhancing the spectra overlap between the self-trapped exciton emission and the Ce-based Frenkel exciton excitation. When implemented as an active layer in light-emitting diodes, they show the maximum brightness and external quantum efficiency of 1073 cd m<sup>-2</sup> and 7.9%, respectively.