Structure, bandgap, photoluminescence evolution and thermal stability improved of Sr replacement apatite phosphors Ca10-xSrx(PO4)6F2:Eu2+ (x = 4, 6, 8)

Zhou, Xufeng; Geng, Wanying; Ding, Jianyan; Wang, Yichao; Wang, Yuhua

doi:10.1016/j.dyepig.2018.01.031

Cited by 32 publications

(11 citation statements)

References 39 publications

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“…The value of n depends on the type of the interband transition: that is n = 2 for direct transition and n = 1/2 for indirect transition. 26 LYMW is a direct transition compound, i.e., n = 2, and the estimated band-gap from the DRS is about 3.91 eV, which is very close to the calculated result (3.71 eV). The slight discrepancy between the calculated band-gap and the experimental one is due to the inherent flaw of DFT calculations with the GGA-PBE functional.…”

Section: Resultssupporting

confidence: 82%

Photoluminescence Properties and Energy Transfers in the Novel LiYMgWO₆: Dy³⁺, Tm³⁺

Fan

et al. 2022

ECS Adv.

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A series of Dy3+/Tm3+ singly doped and co-doped double perovskite-structure compound LiYMgWO6 (LYMW) were prepared by a solid-state route. The structure and photoluminescence properties have been unraveled by combining experiments and first-principles calculations. The crystal structure was determined to be a monoclinic structure with space groups P21. Under the ultraviolet (UV) excitation, Dy3+ and Tm3+ single-doped LYMW samples emit yellowish-white and blue light, respectively. For Dy3+ and Tm3+ co-doped LYMW, the emission can be tuned from blue to white light and eventually to yellow through energy transfers by varying the Dy3+ and Tm3+ concentrations. The sample with 3%Dy3+ and 3%Tm3+ has chromaticity coordinates (0.3405, 0.3378), which are nearest to the ideal white light (0.33,0.33). The energy transfer mechanism is verified to be the quadrupole-quadrupole interaction. The temperature-dependent photoluminescence (PL) spectra show that LYMW: Dy3+, Tm3+ exhibits good thermal stability.

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Section: Resultssupporting

confidence: 82%

Photoluminescence Properties and Energy Transfers in the Novel LiYMgWO₆: Dy³⁺, Tm³⁺

Fan

et al. 2022

ECS Adv.

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“…It can be observed that the bottom of the conduction band is located at G site of Brillouin zone, and the top of valence band is also located at G point for Ca 9 La(PO 4 ) 5 (SiO 4 )F 2 , suggesting that the as‐prepared sample has direct transition and its energy band gaps are estimated to be about 4.24 eV. The calculated energy band gaps is smaller than previous experiment result because the calculated band gap by DFT is somewhat underestimated . The total and partial density of states (DOS) of CLPSF are shown in Figure B.…”

Section: Resultsmentioning

confidence: 82%

“…The calculated energy band gaps is smaller than previous experiment result because the calculated band gap by DFT is somewhat underestimated. 24 The total and partial density of states (DOS) of CLPSF are shown in Figure 2B. It appears that the states in the valance band region is dominated by P-3p, F-2p, and O-2p orbitals ranging from −10 to 0 eV, but the contributions of Si orbitals is not negligible.…”

Section: Methodsmentioning

confidence: 98%

New apatite‐type phosphor Ca₉La(PO₄)₅(SiO₄)F₂:Tb³⁺,Dy³⁺ with improved color rendering index

et al. 2019

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Ca 9 La(PO 4 ) 5 (SiO 4 )F 2 :Tb 3+ ,Dy 3+ (CLPSF:Tb 3+ ,Dy 3+ ) phosphors were successfully prepared using the traditional solid-state technique. The crystal structure was refined and the luminescence properties have been examined in detail. The band gap and electronic structure of Ca 9 La(PO 4 ) 5 (SiO 4 )F 2 were performed by the periodic density functional theory (DFT) calculation. The spectral and fluorescence decay dynamics of CLPSF:Tb 3+ ,Dy 3+ show that the energy transfer behavior between Tb 3+ and Dy 3+ ions is observed. The CLPSF:Tb 3+ ,Dy 3+ phosphors can be efficiently excitable at the wavelengths range from 300 to 500 nm. The emission spectrum covers the whole visible part of the spectra with the sharp emission bands in red, green, and blue regions. The correlated color temperature (CCT) and color rendering index (CRI) of white light emission could be improved by the fine-tuning of the Tb 3+ and Dy 3+ ions ration in accordance with the energy transfer behavior. Thus, the CLPSF:Tb 3+ ,Dy 3+ phosphor could be used as a material for the near-ultraviolet (n-UV) and white lightemitting diodes (w-LEDs). K E Y W O R D Sapatite-type structure, CRI, energy transfer, n-UV-convertible phosphor, phosphor, w-LEDs

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“…Compared with the red emission from the f-f transition of Eu 3+ , the degree of splitting in the 5d energy level of Eu 2+ is determined by the strength of the crystal field and can produce various colors in different luminescence hosts. [19][20][21] Moreover, based on the diversity of their electronic structure, Eu 3+ usually has a higher activation energy and shows a slighter thermal quenching than Eu 2+ . 22,23 Therefore, if Eu 2+ and Eu 3+ exist simultaneously in the same host, the fluorescent intensity ratio of the Eu 2+ and Eu 3+ emission at different temperatures could act as a potential thermometric parameter.…”

Section: Introductionmentioning

confidence: 99%

“…As two different states of a same rare earth element, Eu 2+ and Eu 3+ show noticeably different luminescent properties due to their different electronic structures. Compared with the red emission from the f‐f transition of Eu 3+ , the degree of splitting in the 5d energy level of Eu 2+ is determined by the strength of the crystal field and can produce various colors in different luminescence hosts . Moreover, based on the diversity of their electronic structure, Eu 3+ usually has a higher activation energy and shows a slighter thermal quenching than Eu 2+ .…”

Section: Introductionmentioning

confidence: 99%

Ca₂Na₂La₆(SiO₄)₄(PO₄)₂O: Eu²⁺/Eu³⁺: A visual dual‐emitting fluorescent ratiometric temperature sensor

et al. 2019

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A novel apatite‐based UV‐excited dual‐emitting Ca2Na2La6(SiO4)4(PO4)2O: Eu2+/Eu3+ phosphor (CNL: Eu2+/Eu3+) was designed and successfully synthesized by a solid‐state reaction. Compared with previous reports on this family of materials, a structural study based on DFT calculation exhibited a new consequence that the monovalent ions in this system are more inclined to occupy the seven‐coordinate cationic sites rather than the nine‐coordinate sites. This result was confirmed by the structural refinement and high‐resolution transmission electron microscopy (HRTEM) data. Due to the coexistence of Eu2+ and Eu3+ dopants in the material, under 345 or 392 nm excitation, CNL: 0.02Eu2+/Eu3+ exhibited a green Eu2+ emission band (528 nm) and red Eu3+ emission peaks (around 618 nm). The application potential of CNL:0.02Eu2+/Eu3+ in luminescent thermometry was studied by exploiting the temperature sensitivity of the fluorescent intensity ratio (green/red) at different temperatures. It was found that, under 345 nm excitation, the fluorescent intensity ratio of CNL: 0.02Eu2+/Eu3+ displayed linear correlation over the temperature range of 298 to 473 K with a high sensitivity of 2.82%K−1. Additionally, the emission color of the CNL: 0.02Eu2+/Eu3+ sample under UV lamp (254 and 365 nm) excitation showed an obvious change (from green to red) as the temperature increased from 298 to 473 K (from green to red). These results indicated that CNL: Eu2+/Eu3+ can serve as an excellent visual luminescent ratiometric thermometer. Furthermore, this work provides a novel reference for developing high‐performance luminescence temperature‐sensing materials.

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Structure, bandgap, photoluminescence evolution and thermal stability improved of Sr replacement apatite phosphors Ca10-xSrx(PO4)6F2:Eu2+ (x = 4, 6, 8)

Cited by 32 publications

References 39 publications

Photoluminescence Properties and Energy Transfers in the Novel LiYMgWO₆: Dy³⁺, Tm³⁺

Photoluminescence Properties and Energy Transfers in the Novel LiYMgWO₆: Dy³⁺, Tm³⁺

New apatite‐type phosphor Ca₉La(PO₄)₅(SiO₄)F₂:Tb³⁺,Dy³⁺ with improved color rendering index

Ca₂Na₂La₆(SiO₄)₄(PO₄)₂O: Eu²⁺/Eu³⁺: A visual dual‐emitting fluorescent ratiometric temperature sensor

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Structure, bandgap, photoluminescence evolution and thermal stability improved of Sr replacement apatite phosphors Ca10-xSrx(PO4)6F2:Eu2+ (x = 4, 6, 8)

Cited by 32 publications

References 39 publications

Photoluminescence Properties and Energy Transfers in the Novel LiYMgWO6: Dy3+, Tm3+

Photoluminescence Properties and Energy Transfers in the Novel LiYMgWO6: Dy3+, Tm3+

New apatite‐type phosphor Ca9La(PO4)5(SiO4)F2:Tb3+,Dy3+ with improved color rendering index

Ca2Na2La6(SiO4)4(PO4)2O: Eu2+/Eu3+: A visual dual‐emitting fluorescent ratiometric temperature sensor

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Photoluminescence Properties and Energy Transfers in the Novel LiYMgWO₆: Dy³⁺, Tm³⁺

Photoluminescence Properties and Energy Transfers in the Novel LiYMgWO₆: Dy³⁺, Tm³⁺

New apatite‐type phosphor Ca₉La(PO₄)₅(SiO₄)F₂:Tb³⁺,Dy³⁺ with improved color rendering index

Ca₂Na₂La₆(SiO₄)₄(PO₄)₂O: Eu²⁺/Eu³⁺: A visual dual‐emitting fluorescent ratiometric temperature sensor