Eu2+/Ce3+-doped NaAlSiO4 selective occupation-induced emission structure unit evolution and its luminescence characteristics

• Published in: Optical materials 2023-05, Vol.139, p.113762, Article 113762
• Main Authors: Zhang, Jingwen, Liu, Jian, Zhu, Weihua, Xiong, Ying, Cao, Fabin, Wu, Xingrong, Shen, Xingmei, Liu, Weiming, Wu, Zhaojin
• Format: Article
• Language: English
• Subjects: Emission structure unit; Energy transfer; Ion occupation; Luminescence thermal stability
• ISSN: 0925-3467; 1873-1252
• DOI: 10.1016/j.optmat.2023.113762

NaAlSiO4: xEu2+,yCe3+ blue-red phosphors were prepared by high-temperature melting-icy quenching-heat treatment. The effects of emission structure unit evolution, microstrain, microcrystalline size and selective occupation on the luminescence characteristics of the prepared phosphor were systematically studied by powder X-ray diffraction pattern (XRD) and photoluminescence spectroscopy (PL). In the structure of NaAlSiO4: 2%Eu2+, 2%Ce3+ hexagonal crystalline sodium nepheline, Eu2+ ions occupy the Na+ (II) position to form a EuNa+(II)2+ luminescent structure unit, and Ce3+ ions occupy the Na+ (I) position to form a CeNa+(I)3+ luminescent structure unit. The NaAlSiO4: 2%Eu2+/NaAlSiO4: 2%Ce3+ emits 555 nm yellow-green light/395 nm blue-violet light under the excitation of 354 nm/298 nm, respectively, which is derived from the 5d-4f transition of Eu2+ and Ce3+. There is energy transfer of Ce3+→Eu2+ in the sodium nepheline matrix, of which the transport pathway is m EuNa+(II)2+ ←O←n CeNa+(I)3+ →O→m EuNa+(II)2+, and the transport mechanism is electric quadrode-electric quadrupole interaction, and the energy transfer efficiency reaches 98.6%. The sodium nepheline NaAlSiO4: 2%Eu2+, 2%Ce3+ phosphor with energy level barrier 0.386 eV, possesses good thermal stability. This single-phase aluminosilicate multicolor phosphor has potential application value for WLED illumination and PDP display. •The correlation between the luminescence characteristics and the structure of the material was established y=14.91x1+109093.16x2+1419.52.•Sites occupancy of Eu2+/Ce3+ codoped in matrix. The selective occupancy of Eu2+/Ce3+ in the light-emitting structural units were constructed by Eu2+/Ce3+ doped NaAlSiO4.•The formation process of luminescent structural units and the energy transfer process were studied, and the energy transfer model was proposed.