Luminescence characterization of (Ca1−xZnx)Ga2S4:Eu2+ phosphors for a white light-emitting diode

Kim, Yong-Kyu; Cho, Dong-Hee; Jeong, Yong-Kwang; Nah, Min-Kook; Kim, Kwang‐Bok; Kang, Jun‐Gill

doi:10.1016/j.materresbull.2010.04.021

Cited by 22 publications

(4 citation statements)

References 34 publications

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“…These results can also be explained by the nephelauxetic effect. 18 The substituted small amount of Zn 2+ ion leads to an interaction between the 5d electron of Eu 2+ and the ligand, which expands the electron cloud of the 5d orbital of Eu 2+ . Such nephelauxetic effect increased the covalent of Eu 2+ , accordingly, luminescence intensity was enhanced and red shift was observed.…”

Section: Resultsmentioning

confidence: 99%

Sr_0.95Zn_0.05Se:Eu²⁺ and CdSe/ZnS Nanocrystals Hybrid Phosphors for Enhancing Color Rendering Index of White Light Emitting Diode

Chung¹,

Jung²,

Lee³

et al. 2012

j nanosci nanotechnol

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In this study, the yellow emitting cubic structure of Sr0.95Zn0.05Se:Eu2+ phosphors were prepared by high temperature solid state reaction. The Sr0.95Zn0.05Se:Eu2+ phosphors exhibited strong excitation intensity under 400-460 nm region, and broad band emission appeared at around 545-600 nm due to the d-f transition of Eu2+. To enhance the red emission, HDA/TOP/TOPO capped CdSe/ZnS NCs were synthesized via fast nucleation and slow growth method. The narrow emission peak was located at 615 nm with 69% of high quantum yield. Bright white emission was generated by combining a 460 nm InGaN LED chip with CdSe/ZnS NCs and Sr0.95Zn0.05Se:Eu2+ hybrid phosphors. The fabricated white LEDs showed warm white light with acceptable CIE chromaticity coordinate variation from (0.343, 0.255) at 20 mA to (0.335, 0.250) at 50 mA. The addition of CdSe/ZnS NCs contributed to the extension of white light spectrum by supplement of the red region. The color rendering index was largely enhanced from 41.7 to 79.7 compared to the Sr0.95Zn0.05Se:Eu2+ based phosphors white LED.

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Section: Resultsmentioning

confidence: 99%

Sr_0.95Zn_0.05Se:Eu²⁺ and CdSe/ZnS Nanocrystals Hybrid Phosphors for Enhancing Color Rendering Index of White Light Emitting Diode

Chung¹,

Jung²,

Lee³

et al. 2012

j nanosci nanotechnol

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“…This result explains that the substituted Zn 2+ ion with small amount causes the nephelauxetic effect on the Eu 2+ emission. Because of the nephelauxetic effect on the 5d orbital, the Zn 2+ ion may cause an interaction between the 5d electron of Eu 2+ and the ligand; therefore the electron clouds of the 5d orbital of Eu 2+ are expanded [12]. The nephelauxetic effect increases the covalent distribution of Eu 2+ , thus red-shifting and enhancing the Eu 2+ luminescence.…”

Section: Luminescence Propertiesmentioning

confidence: 99%

Luminous properties of Sr1−Zn Se:Eu2+ phosphors for LEDs application

Chung

Kim

et al. 2011

Journal of Crystal Growth

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“…In this study, we prepared SrS:Ce powders of different concentrations by the solid‐state diffusion method. Only a limited number of studies have examined the luminescence properties of SrS phosphors in regard to LED applications with blue excitation . This article reports the structural characterization on the basis of X‐ray diffraction (XRD), field emission scanning electron microscopy (FESEM), high‐resolution transmission electron microscopy (HRTEM) and energy‐dispersive X‐ray (EDX) analysis, and studies of optical properties were also carried out on the basis of UV–Vis diffuse reflectance spectra, photoluminescence (PL) and long afterglow (decay) behavior.…”

Section: Introductionmentioning

confidence: 99%

Nanocrystalline SrS:Ce³⁺ system for the generation of white light‐emitting diodes

Mishra

Kshatri²,

Khare

et al. 2016

Luminescence

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Nanocrystalline SrS phosphors doped with Ce ions at different concentrations (0.5, 1, 1.5 and 2 mol%) are synthesized via the solid-state diffusion method (SSDM), which is suitable for the large-scale production of phosphors in industrial applications. The as-prepared samples are characterized using an X-ray diffraction (XRD) technique, field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM) and energy-dispersive X-ray (EDX) analysis. The optical properties of these phosphors are analyzed using reflectance spectra, photoluminescence spectra and afterglow decay curves. The cubic structure of the SrS phosphor is confirmed by XRD analysis and the crystallite size calculated by Scherer's formula using XRD data shows the nanocrystalline nature of the phosphors. No phase change is observed with increasing concentrations of Ce ions. The surface morphology of the prepared phosphors is determined by FESEM, which shows a sphere-like structure and good connectivity of the grains. The authenticity of the formation of nanocrystalline phosphors is examined by HRTEM analysis. Elemental compositional information for the prepared phosphors is gathered by EDX analysis. Photoluminescence studies reveal that the emission spectra of the prepared phosphor shows broad band emission centered at 458 and 550 nm due to the transition of electrons from the 5d → 4f energy levels. The afterglow decay characteristics of different as-synthesized SrS:Ce nanophosphors are conceptually described. Copyright © 2016 John Wiley & Sons, Ltd.

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Luminescence characterization of (Ca1−xZnx)Ga2S4:Eu2+ phosphors for a white light-emitting diode

Cited by 22 publications

References 34 publications

Sr_0.95Zn_0.05Se:Eu²⁺ and CdSe/ZnS Nanocrystals Hybrid Phosphors for Enhancing Color Rendering Index of White Light Emitting Diode

Sr_0.95Zn_0.05Se:Eu²⁺ and CdSe/ZnS Nanocrystals Hybrid Phosphors for Enhancing Color Rendering Index of White Light Emitting Diode

Luminous properties of Sr1−Zn Se:Eu2+ phosphors for LEDs application

Nanocrystalline SrS:Ce³⁺ system for the generation of white light‐emitting diodes

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Luminescence characterization of (Ca1−xZnx)Ga2S4:Eu2+ phosphors for a white light-emitting diode

Cited by 22 publications

References 34 publications

Sr0.95Zn0.05Se:Eu2+ and CdSe/ZnS Nanocrystals Hybrid Phosphors for Enhancing Color Rendering Index of White Light Emitting Diode

Sr0.95Zn0.05Se:Eu2+ and CdSe/ZnS Nanocrystals Hybrid Phosphors for Enhancing Color Rendering Index of White Light Emitting Diode

Luminous properties of Sr1−Zn Se:Eu2+ phosphors for LEDs application

Nanocrystalline SrS:Ce3+ system for the generation of white light‐emitting diodes

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Sr_0.95Zn_0.05Se:Eu²⁺ and CdSe/ZnS Nanocrystals Hybrid Phosphors for Enhancing Color Rendering Index of White Light Emitting Diode

Sr_0.95Zn_0.05Se:Eu²⁺ and CdSe/ZnS Nanocrystals Hybrid Phosphors for Enhancing Color Rendering Index of White Light Emitting Diode

Nanocrystalline SrS:Ce³⁺ system for the generation of white light‐emitting diodes