Transparent Ce:Y3Al5O12 ceramic phosphors for white light-emitting diodes

Wei, Nian; Lu, Tiecheng; Li, Feng; Zhang, Wei; Ma, Benyuan; Lù, Zhongwen; Qi, Jianqi

doi:10.1063/1.4742896

Cited by 161 publications

(81 citation statements)

References 20 publications

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“…However, the observed experimental result does not appear to be consistent with the prediction of crystal field theory, which previously has been employed to explain a resultant shift in a number of circumstances: the heat treatment temperature on sample phosphors [18,19] [29,30] and the different doping concentration of the Ce 3+ ion [31][32][33]. According to the electron cloud effect and crystal field theory, the radiative photon energy of the rare-earth ion is determined by the average lanthanide-ligand bond length when considering that the effective ionization degree is constant: First, consider the nephelauxetic effect which determines the barycenter energies of levels.…”

Section: Shift Of Emission Bandcontrasting

confidence: 47%

“…The shift of emission band should have a very similar mechanism as other reports [7,[18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] suggested since they are all related to a change of the coordination circumstance of the Ce 3+ ion. However, the observed experimental result does not appear to be consistent with the prediction of crystal field theory, which previously has been employed to explain a resultant shift in a number of circumstances: the heat treatment temperature on sample phosphors [18,19] [29,30] and the different doping concentration of the Ce 3+ ion [31][32][33].…”

Section: Shift Of Emission Bandmentioning

confidence: 49%

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Spectral analysis for broadband fluorescence: temperature sensing with the YAG:Ce phosphor as an example

Zhang¹,

Wang²,

Cai³

et al. 2016

Opt. Mater. Express

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Temperature-dependent fluorescence of YAG:Ce was studied as an example of a spectral characterization method. According to the steady-state emission at various temperatures, four types of temperature sensing functions were retrieved using behaviors of 1) wavenumber at emission band maximum magnitude, 2) wavenumber of emission band barycenter, 3) emission bandwidth, and 4) the ratio of intensities at different wavelengths in the emission band. All four types of functions demonstrate a near linear relationship with temperature in the measured temperature range. Function No. 2 shows finer precision than function No. 1, while they have the same meaning in physics. Mechanisms of the temperature dependence are discussed after a brief review of emission peak shifts of Ce 3+ -doped garnets. Function No. 3 shows an abnormal narrowing of the band with increasing temperature which can be related to the narrowing ground levels' splitting gap. In the experiment, the two novel spectral characterization methods showed their advantages: the barycenter technique contains the smallest uncertainty, and the self-referenced intensity ratio technique provides flexible ratiometric sensing functions for various measurement needs. Seshadri, "Rapid microwave preparation of highly efficient Ce 3+ -substituted garnet phosphors for solid state white lighting," Chem. Mater. 24(6), 1198-1204 (2012). 10. S. P. Ying, P. T. Chou, and H. K. Fu, "Influence of the temperature dependent spectral power distribution of light-emitting Diodes on the illuminance responsivity of a photometer," Opt. Lasers Eng. 51(10), 1179-1184 (2013). Defects Solids 158(1-6), 39-47 (2003). 14. M. Grinberg, "High pressure spectroscopy of rare earth ions doped crystals -new results," Opt. Mater. 28(1-2), 26-34 (2006) 8-12 (2015).

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Section: Shift Of Emission Bandcontrasting

confidence: 47%

Section: Shift Of Emission Bandmentioning

confidence: 49%

Spectral analysis for broadband fluorescence: temperature sensing with the YAG:Ce phosphor as an example

Zhang¹,

Wang²,

Cai³

et al. 2016

Opt. Mater. Express

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“…The manufacturing process during of separate ceramics is similar to that reported in our previous works [23][24][25][26][27]. Neodymium nitrate (Nd(NO 3 99.99%) and ammonium aluminum sulfate (NH 4 Al(SO 4 ) 2 ·12H 2 O, 99.99%) were mixed together in stoichiometric proportions to form the chemical stoichiometry composition, with Nd 3+ doping concentrations of 0 at.% and 2.0 at.%, respectively, in distilled water.…”

Section: Nd:yag/yag Transparent Ceramicsmentioning

confidence: 97%

“…Nevertheless, the thermal diffusion bonding technology of Nd:YAG/YAG ceramics has not yet been investigated systematically, and especially, the optimal conditions and underlying mechanism of diffusion across contact surfaces of bulk ceramics are seldom reported so far. We previously studied the synthesis of high purity and agglomeration-free YAG nano-powders [23][24][25], the influence of post-annealing and post-HIP on Nd:YAG ceramics [26,27], and light scattering loss of Nd:YAG ceramics by pores [28]. Most recently we fabricated composite Nd:YAG/YAG transparent ceramics by vacuum sintering.…”

Section: Introductionmentioning

confidence: 99%

Direct thermal diffusion bonding of Nd:YAG/YAG composite transparent ceramics by vacuum sintering

Zhang

Chen

et al. 2017

Journal of the European Ceramic Society

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“…Such lattice expansion or shrinkage could be a result of the heat treatment temperature on sample phosphors [13,14] or an effect of the nanoscale sample particle size [15,16]. Alternatively there may have been Y 3+ substitution by Gd 3+ [17][18][19][20][21][22][23] or Tb 3+ [24] or again Lu 3+ [25,26]; perhaps there was a different doping concentration of Ce 3+ [27][28][29]. Even though these articles reported very similar wavelength shifts of the emission band maximum, the mechanism of such a lattice effect on Ce 3+ emission were ambiguously allocated to strengthened or weakened crystal field in most of the articles.…”

Section: +mentioning

confidence: 99%

Stress- and Temperature-Dependent Wideband Fluorescence of a Phosphor Composite for Sensing Applications

Zhang

Baxter

et al. 2016

Exp Mech

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As both stress and temperature can alter the lattice of a solid phosphor in a similar way, the dopant rare-earth ion may be used as a probe for either parameter using the same sensing mechanism. Here, a wideband phosphor, YAG:Ce is used as a micro stress sensor at very low magnitudes of compressive stress. The sensing resolution can be smaller than 0.06 N/mm 2 in the range of 0~1.2 N/mm 2 with a sensitivity of 11 cm −1 /MPa. The sensitivity is about a hundred times larger than the coefficient reported under hydrostatic pressure. The barycenter energy of the emission band of a phosphor can be used to indicate stress and/or temperature change, producing a precision beyond the spectroscopic resolution limit. The sensing functions obtained from the barycenter shift are superior to those from peak shifts. The stress/temperature dependent barycenter shift of the observed fluorescence bands of YAG:Ce were similar in magnitude. Mechanisms involving the nephelauxetic effect, crystal field effect and site symmetry of dopant ions are explored as explanations of the experimental phenomena.

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Transparent Ce:Y₃Al₅O₁₂ ceramic phosphors for white light-emitting diodes

Cited by 161 publications

References 20 publications

Spectral analysis for broadband fluorescence: temperature sensing with the YAG:Ce phosphor as an example

Spectral analysis for broadband fluorescence: temperature sensing with the YAG:Ce phosphor as an example

Direct thermal diffusion bonding of Nd:YAG/YAG composite transparent ceramics by vacuum sintering

Stress- and Temperature-Dependent Wideband Fluorescence of a Phosphor Composite for Sensing Applications

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