Investigations on the luminescence properties of Na0.34Ca0.66Al1.66Si2.34O8:Eu2+/Eu3+/Sm3+ phosphors

• The blue and red emitting NCAS:Eu2+, Eu3+, Sm3+ phosphors were designed.
• The NCAS:Eu2+, Eu3+, Sm3+ phosphors could have potential application in white LEDs.
• The spectra features are helpful to understand the structural feature of NCAS.
• The results can provide useful basic data for further work of phosphor study.

Na0.34Ca0.66Al1.66Si2.34O8:Eu2+/Eu3+/Sm3+ (NCAS:Eu2+/Eu3+/Sm3+) phosphors were prepared by solid-state reaction method, and their photoluminescence properties were investigated. The optical bandgap of the NCAS compound was determined to be 4.04 eV experimentally. The excitation spectrum of NCAS:2%Eu2+ shows a broad excitation band from 240 to 410 nm, which could match with the near-ultraviolet LED chip. Upon 365 nm excitation, blue emissions between 375 and 650 nm have been obtained, accompanied with a continuous red-shift for the predominated emission peaks with increasing Eu2+ concentration. Red and red–orange emissions are gained in the Eu3+/Sm3+ activated NCAS phosphors, respectively. And the spectra features reveal the Eu3+ and Sm3+ ions occupy asymmetry sites. The above investigation results indicate the NCAS:Eu2+/Eu3+/Sm3+ phosphors could have promising applications in white LEDs.

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