Ce 4+ -based charge transfer phosphor is not common and has been reported mainly in Sr 2 CeO 4 with an excitation band peaking at ∼290 nm, mismatching with the near-ultraviolet light emitting diodes. Herein, we report a new series of Ce 4+ -based compounds Sr 4.4 Ce 2.6 REZnO 12 (RE = Y, La, and Eu) capable of photoluminescence induced by O 2- -Ce 4+ charge transfer excitation under near-ultraviolet-visible light. The crystal structure of Sr 4.4 Ce 2.6 EuZnO 12 was determined by single crystal X-ray diffraction. The RE = La and Y samples were confirmed to be iso-structure compounds of the RE = Eu sample by powder X-ray diffraction. By introducing highly covalent Zn 2+ -O 2- bonds into the framework, the Ce 4+ -O 2- bonds are lengthened due to the effect of the Ce 4+ -O 2- -Zn 2+ stretch. The lengthened Ce 4+ -O 2- bond weakens the repulsion of the electrons between Ce 4+ and O 2- , thereby lowering the charge transfer energy to the visible light region. Incorporation of Eu 3+ into the present compounds realized red emission under near-ultraviolet-visible excitation by the O 2- -Ce 4+ charge transfer followed by energy transfer to Eu 3+ .
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Inorganic Chemistry