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Interaction between the exchanged Mn 2+ and Yb 3+ ions confined in zeolite-Y and their luminescence behaviours

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ABSTRACT

Luminescent zeolites exchanged with two distinct and interacted emissive ions are vital but less-studied for the potential applications in white light emitting diodes, solar cells, optical codes, biomedicine and so on. Typical transition metal ion Mn2+ and lanthanide ion Yb3+ are adopted as a case study via their characteristic transitions and the interaction between them. The option is considered with that the former with d-d transition has a large gap between the first excited state 4T1 and the ground state 6A1 (normally >17,000 cm−1) while the latter with f-f transition has no metastable excited state above 10,000 cm−1, which requires the vicinity of these two ions for energy transfer. The results of various characterizations, including BET measurement, photoluminescence spectroscopy, solid-state NMR, and X-ray absorption spectroscopy, etc., show that Yb3+ would preferably enter into the zeolite-Y pores and introduction of Mn2+ would cause aggregation of each other. Herein, cation-cation repulsion may play a significant role for the high valence of Mn2+ and Yb3+ when exchanging the original cations with +1 valence. Energy transfer phenomena between Mn2+ and Yb3+ occur only at elevated contents in the confined pores of zeolite. The research would benefit the design of zeolite composite opto-functional materials.

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(a) UC luminescence of 0.2Yb, xMn/zeolite-Y (x = 0.6, 0.8, 1.0) under excitation of 980 nm laser diode; (b) near infrared luminescence of Yb3+ in 0.2Yb, xMn/zeolite-Y (x = 0.2, 0.4, 0.6, 0.8, 1.0) samples under excitation of 413 nm xenon light; decay curves of Yb3+ emission in (c) yYb/ zeolite-Y (y = 0.05, 0.1, 0.2, 0.4, 0.8) samples and (d) 0.2Yb, xMn/ zeolite-Y (x = 0, 0.2, 0.4, 0.6, 0.8, 1.0) samples upon excitation of 980 nm laser diode.
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f6: (a) UC luminescence of 0.2Yb, xMn/zeolite-Y (x = 0.6, 0.8, 1.0) under excitation of 980 nm laser diode; (b) near infrared luminescence of Yb3+ in 0.2Yb, xMn/zeolite-Y (x = 0.2, 0.4, 0.6, 0.8, 1.0) samples under excitation of 413 nm xenon light; decay curves of Yb3+ emission in (c) yYb/ zeolite-Y (y = 0.05, 0.1, 0.2, 0.4, 0.8) samples and (d) 0.2Yb, xMn/ zeolite-Y (x = 0, 0.2, 0.4, 0.6, 0.8, 1.0) samples upon excitation of 980 nm laser diode.

Mentions: 0.2Yb, xMn/zeolite-Y (x = 0.8, 1.0) samples could show UC luminescence under excitation of 980 nm laser diode, as seen in Fig. 6a, while those samples (x = 0, 0.2, 0.4, 0.6) exhibit no apparent UC emissions. Since there is a large gap between the first excited state of 4T1 and ground state of 6A1 for Mn2+ (normally > 17,000 cm−1) and there is no metastable excited state above 10,000 cm−1 for Yb3+ ion2627282930, it normally requires the vicinity of Mn2+-Yb3+ ions in the lattice for super exchange-interaction or cooperative sensitization based UC process. Therefore, when Mn2+ content is high enough (x ≥ 0.8), the Mn2+ ions tend to show up at the neighbor of Yb3+ ions. Furthermore, an UC emission band located at 505 nm, which is attributed to the UC process of Yb3+-Yb3+ ion pair, appears when x ≥ 0.8. It also manifests that introduction of high Mn2+ content would make Yb3+ ions aggregate. Interestingly, the near infrared luminescence 2F5/2 → 2F7/2 of Yb3+ in 0.2Yb, xMn/zeolite-Y (x = 0.8, 1.0) samples under excitation of Mn2+ are apparently observed in Fig. 6b, suggesting that there is energy transfer between Mn2+ and Yb3+ despite of the large gap between 4T1 of Mn2+ and 2F5/2 of Yb3+. It also implies the distance between Mn2+and Yb3+ is shortened enough for the energy transfer took place for samples with x ≥ 0.8. The decay curves of Yb3+ in yYb/zeolite-Y (y = 0.05, 0.1, 0.2, 0.4, 0.8) and 0.2Yb, xMn/zeolite-Y (x = 0.2, 0.4, 0.6, 0.8, 1.0) samples in Fig. 6c,d show little change, which is quite different from that of Mn2+. But by focusing in detail, the decay curves show more linear when increasing the Yb3+ contents or the Mn2+ contents, again manifesting the aggregation of Yb3+ ions. It is also consistent with the luminescence behavior in Fig. 6a,b. Accordingly, it can be inferred that the aggregation of Yb3+ ions reduces defects, which makes the decay curves of Yb3+ ion with few defects surrounded exhibit single-exponential behaviour.


Interaction between the exchanged Mn 2+ and Yb 3+ ions confined in zeolite-Y and their luminescence behaviours
(a) UC luminescence of 0.2Yb, xMn/zeolite-Y (x = 0.6, 0.8, 1.0) under excitation of 980 nm laser diode; (b) near infrared luminescence of Yb3+ in 0.2Yb, xMn/zeolite-Y (x = 0.2, 0.4, 0.6, 0.8, 1.0) samples under excitation of 413 nm xenon light; decay curves of Yb3+ emission in (c) yYb/ zeolite-Y (y = 0.05, 0.1, 0.2, 0.4, 0.8) samples and (d) 0.2Yb, xMn/ zeolite-Y (x = 0, 0.2, 0.4, 0.6, 0.8, 1.0) samples upon excitation of 980 nm laser diode.
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Related In: Results  -  Collection

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f6: (a) UC luminescence of 0.2Yb, xMn/zeolite-Y (x = 0.6, 0.8, 1.0) under excitation of 980 nm laser diode; (b) near infrared luminescence of Yb3+ in 0.2Yb, xMn/zeolite-Y (x = 0.2, 0.4, 0.6, 0.8, 1.0) samples under excitation of 413 nm xenon light; decay curves of Yb3+ emission in (c) yYb/ zeolite-Y (y = 0.05, 0.1, 0.2, 0.4, 0.8) samples and (d) 0.2Yb, xMn/ zeolite-Y (x = 0, 0.2, 0.4, 0.6, 0.8, 1.0) samples upon excitation of 980 nm laser diode.
Mentions: 0.2Yb, xMn/zeolite-Y (x = 0.8, 1.0) samples could show UC luminescence under excitation of 980 nm laser diode, as seen in Fig. 6a, while those samples (x = 0, 0.2, 0.4, 0.6) exhibit no apparent UC emissions. Since there is a large gap between the first excited state of 4T1 and ground state of 6A1 for Mn2+ (normally > 17,000 cm−1) and there is no metastable excited state above 10,000 cm−1 for Yb3+ ion2627282930, it normally requires the vicinity of Mn2+-Yb3+ ions in the lattice for super exchange-interaction or cooperative sensitization based UC process. Therefore, when Mn2+ content is high enough (x ≥ 0.8), the Mn2+ ions tend to show up at the neighbor of Yb3+ ions. Furthermore, an UC emission band located at 505 nm, which is attributed to the UC process of Yb3+-Yb3+ ion pair, appears when x ≥ 0.8. It also manifests that introduction of high Mn2+ content would make Yb3+ ions aggregate. Interestingly, the near infrared luminescence 2F5/2 → 2F7/2 of Yb3+ in 0.2Yb, xMn/zeolite-Y (x = 0.8, 1.0) samples under excitation of Mn2+ are apparently observed in Fig. 6b, suggesting that there is energy transfer between Mn2+ and Yb3+ despite of the large gap between 4T1 of Mn2+ and 2F5/2 of Yb3+. It also implies the distance between Mn2+and Yb3+ is shortened enough for the energy transfer took place for samples with x ≥ 0.8. The decay curves of Yb3+ in yYb/zeolite-Y (y = 0.05, 0.1, 0.2, 0.4, 0.8) and 0.2Yb, xMn/zeolite-Y (x = 0.2, 0.4, 0.6, 0.8, 1.0) samples in Fig. 6c,d show little change, which is quite different from that of Mn2+. But by focusing in detail, the decay curves show more linear when increasing the Yb3+ contents or the Mn2+ contents, again manifesting the aggregation of Yb3+ ions. It is also consistent with the luminescence behavior in Fig. 6a,b. Accordingly, it can be inferred that the aggregation of Yb3+ ions reduces defects, which makes the decay curves of Yb3+ ion with few defects surrounded exhibit single-exponential behaviour.

View Article: PubMed Central - PubMed

ABSTRACT

Luminescent zeolites exchanged with two distinct and interacted emissive ions are vital but less-studied for the potential applications in white light emitting diodes, solar cells, optical codes, biomedicine and so on. Typical transition metal ion Mn2+ and lanthanide ion Yb3+ are adopted as a case study via their characteristic transitions and the interaction between them. The option is considered with that the former with d-d transition has a large gap between the first excited state 4T1 and the ground state 6A1 (normally >17,000 cm−1) while the latter with f-f transition has no metastable excited state above 10,000 cm−1, which requires the vicinity of these two ions for energy transfer. The results of various characterizations, including BET measurement, photoluminescence spectroscopy, solid-state NMR, and X-ray absorption spectroscopy, etc., show that Yb3+ would preferably enter into the zeolite-Y pores and introduction of Mn2+ would cause aggregation of each other. Herein, cation-cation repulsion may play a significant role for the high valence of Mn2+ and Yb3+ when exchanging the original cations with +1 valence. Energy transfer phenomena between Mn2+ and Yb3+ occur only at elevated contents in the confined pores of zeolite. The research would benefit the design of zeolite composite opto-functional materials.

No MeSH data available.


Related in: MedlinePlus