Issue 45, 2019

Luminescent silver–lithium-zeolite phosphors for near-ultraviolet LED applications

Abstract

Silver clusters (AgCLs) confined in zeolites show remarkable luminescence properties, displaying high photoluminescence quantum efficiencies combined with tunable visible light emission characteristics, making them highly promising phosphors in lighting devices. However, to date the lack of efficient near-ultraviolet (NUV) and blue excitable silver zeolites has hindered their use in remote LEDs. In this report, we show the utilization of Ag-zeolites in a NUV-LED device, displaying highly efficient green emission with an external quantum efficiency of 83% and a broad excitation range between 300 and 400 nm. This phosphor material was obtained by confining AgCLs in a dehydrated fully Li-exchanged Linde-type A (LTA) zeolite. The unique effect of Li+ ions and dehydration, on the luminescence properties of AgCLs, originates from the structural changes of both the zeolite framework, and the ligand coordinated tetrahedral Ag4 clusters, as observed by X-ray diffraction analysis and X-ray excited optical luminescence–X-ray absorption fine structure (XEOL-XAFS) method, respectively. Moreover, photophysical evidence showed long decay times for these samples in the order of 210 μs, responsible for the steady-state emission, which most likely originates from the decay of the triplet state with a charge transfer character of Ag4(O2) tetrahedral clusters surrounded by 6 lithium cations confined in the sodalite cages of LTA zeolites.

Graphical abstract: Luminescent silver–lithium-zeolite phosphors for near-ultraviolet LED applications

Supplementary files

Article information

Article type
Paper
Submitted
23 Aug 2019
Accepted
27 Oct 2019
First published
28 Oct 2019

J. Mater. Chem. C, 2019,7, 14366-14374

Luminescent silver–lithium-zeolite phosphors for near-ultraviolet LED applications

W. Baekelant, S. Aghakhani, E. Fron, C. Martin, C. Woong-Kim, J. A. Steele, T. De Baerdemaeker, F. d’Acapito, D. Chernysov, M. van der Auweraer, P. Lievens, D. Grandjean, M. Roeffaers, J. Hofkens and E. Coutino-Gonzalez, J. Mater. Chem. C, 2019, 7, 14366 DOI: 10.1039/C9TC04674G

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements