Broadband NaK2Li[Li3SiO4]4:Ce Alkali Lithosilicate Blue Phosphors
Journal
Journal of Physical Chemistry Letters
Journal Volume
11
Journal Issue
16
Pages
6621-6625
Date Issued
2020
Author(s)
Fang, M.-H.
Chen, P.-Y.
Bao, Z.
Majewska, N.
Leśniewski, T.
Mahlik, S.
Grinberg, M.
Sheu, H.-S.
Lee, J.-F.
Abstract
Phosphors with a rigid and symmetrical structure are urgently needed. The alkali lithosilicate family (A[Li3SiO4]) has been extensively studied with a narrow emission band due to its unique cuboid-coordinated environment and rigid structure. However, here we demonstrate for the first time Ce-doped NaK2Li[Li3SiO4]4 phosphors with a broad emission band, a high internal quantum efficiency (85.6%), and excellent thermal stability. Photoluminescence indicates the Ce's preference to occupy the Na+ site, leading to a strong blue color emission with peak maxima at 417 and 450 nm. Temperature- and pressure-dependent photoluminescence reveals thermal stability and a phase transition. Moreover, the X-ray absorption near-edge structure reveals the mixing of Ce3+ and Ce4+ in the materials; this result differs from that of Eu2+-doped A[Li3SiO4] phosphors. The charge compensation process is then proposed to explain this difference. This study not only provides insights into Ce-doped UCr4C4-type phosphors but also explains the charge compensation mechanism of the aliovalent doping process.
SDGs
Type
journal article