Deep traps in CaS:Eu and CaS:Ce phosphors

Георгобиани, А. Н.; Грузинцев, А. Н.; Nikiforova, T. V.; Xu, Xurong; Wang, Yongsheng

doi:10.1007/bf02758919

Cited by 5 publications

(2 citation statements)

References 9 publications

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“…[12][13][14][15] In order to get warm white-light emission and a high color rendering index, a red phosphor is added to the system, which results in favorable properties. [16][17][18][19][20][21] Another excellent option to generate efficient warm white-light sources is to use a single-component phosphor, which can have advantages such as better stability and reproducibility, no phase separation, and simpler fabrication processes. Some research groups have made efforts to develop such phosphors, [22][23][24] for example, Ba 3 MgSi 2 O 8 :Eu 2+ ,Mn 2+ , CaMgSi 2 O 6 :Eu 2+ ,Mn 2+ , and Sr 3 B 2 O 6 :Ce 3+ ,Eu 2+ .…”

Section: Introductionmentioning

confidence: 99%

Luminescence and energy transfer of a color tunable phosphor: Dy3+-, Tm3+-, and Eu3+-coactivated KSr4(BO3)3 for warm white UV LEDs

et al. 2012

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A series of Dy 3+ -, Tm 3+ -, Eu 3+ -coactivated KSr 4 (BO 3 ) 3 phosphors were synthesized via a standard solidstate reaction under normal ambient air, and the emission colors could be tuned from blue to yellow and then to red, including almost all the white light region, through tuning the energy transfer. It was discovered that the energy is transferred from Tm 3+ to Dy 3+ by: directly observing overlap of the excitation spectrum of Dy 3+ and the emission spectrum of Tm 3+ ; the systematic relative decline and growth of emission bands of Tm 3+ and Dy 3+ , respectively; and faster decay times of the blue emissions from energy donors. The resonance-type energy transfer from Tm 3+ to Dy 3+ was demonstrated to be via the dipole-quadrupole mechanism and the critical distance of energy transfer was calculated to be 20.7 A. Rietveld refinements of the crystal structures of the products obtained from powder X-ray diffraction (XRD) elucidated a preferable occupancy in the crystal unit for the doped rare-earth cations, which well explained the formation of the Tm 3+ -Dy 3+ close pair. By utilizing the principle of energy transfer, we have demonstrated that with appropriate tuning of activator content, KSr 4 (BO 3 ) 3 :Dy 3+ ,Tm 3+ ,Eu 3+ phosphors exhibit great potential for use as single-component phosphors for warm white ultraviolet light-emitting diodes (UV LEDs).

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