The Role of Calcium Manganese Orthophosphate in Halophosphate Phosphors

Self Cite

Total chemical analysis of luminescent apatite together with quantitative x-ray diffraction analysis for secondary phases have made it possible to delineate the maximum permissible nonstoichiometry. Based on the accuracy of the various methods and expressed as a deficiency of calcium, the extent of nonstoichiometry is less than the absence of one calcium in every 380 calcium sites. Quantitative experimental evidence is also presented to support the hypothesis for charge compensation of antimony by a corresponding oxygen substitution at halogen sites.

Section: Stoichiometry Of Luminescent Apatitesmentioning

confidence: 50%

Section: Forms Of Convection Forced Convection At a Rotating Crystalmentioning

confidence: 99%

Stoichiometry of Luminescent Apatites

Rabatin¹,

Gillooly²,

Hunter³

1967

Self Cite

“…This pink color has been ascribed by Rabatin and Gillooly to Mn +3 in calcium orthophosphate, a second phase component often present in halophosphate phosphors (7). This pink color has been ascribed by Rabatin and Gillooly to Mn +3 in calcium orthophosphate, a second phase component often present in halophosphate phosphors (7).…”

Section: Methodsmentioning

confidence: 89%

“…This Mn (I) envelope shift is primarily responsible for the color shift observed in the CW phosphor relative to calcium fluorophosphate. The shift is not due to a redistribution between the Ca(I) and Ca(II) sites due to the introduction of Sb, Cd, and C1 as Johnson proposed (7), nor due to the formation of new Mn(C1) centers as Butler and Jerome (5) proposed, although the formation of Mn(C1) centers does occur to some degree and does cause a slight additional wavelength shift to the composite Mn +~ fluorescence envelope.…”

mentioning

confidence: 91%

The Effect of Rapid Cooling on Divalent Manganese Ions in Calcium Fluoro-Chlorophosphate Phosphors

Ryan¹,

Vodoklys²

1971

Quenching experiments were performed on manganese‐activated calcium fluoro‐chlorophosphate phosphors. Changes in the optical properties of the manganese ions due to quenching were studied in order to explain the manganese fluorescent envelope shift in quenched phosphors reported by other workers. We find that quenching causes a change in the nearest halogen neighbors of manganese ions located on the so‐called “Ca(II)” positions. In slowly cooled phosphors these ions have mostly chlorine ions as nearest neighbors while in the quenched phosphors many of the chlorine ions are replaced with fluorine. It is shown that this redistribution will produce a shift in the manganese fluorescence envelope equal in magnitude to that experimentally observed.

“…Room temperature luminescence in a-SiC single crystals containing grown p-n junctions with B and N dopants was investigated by Addamiano, Potter, and Ozarow (11). More recently relationships between band gaps and luminescence in different SiC polytypes doped with boron were reported independently by Addamiano (12) and Kholuyanov (13). It seems likely that the mechanism of light emission in different B-doped SiC polytypes is very much the same.…”

Section: Arrigo Addamianomentioning

confidence: 89%

Sb3+ and Mn2+ Activated Calcium Halophosphate Phosphors from Flux-Grown Apatites

Wachtel

1966

reduce the amounts of other impurities also if the oxychloride recrystallization process is used. It is evident that commercial sources of zirconia, if used in the preparation of other zirconium compounds, will introduce the same undesirable impurities if luminescence phenomena involving other activator ions are being considered, for example, the rare earths. It is possible that these impurities may not have as pronounced a detrimental effect in such compounds as they do in ZrO2 alone.It is probable that Ti 4+ replaces Zr 4+ in monoclinic ZrO2 substitutionally rather than interstitially. The usual coordination of Ti 4+ in oxide compounds is octahedral. In monoclinic ZrO2, however, the coordination of Ti 4+ is likely the same unusual asymmetric sevenfold coordination discussed previously. This highly asymmetric environment may account for the strong emission which can be developed.The slow build-up of steady-state luminescence and the long persistence of irradiated samples at room temperature is probably related to the filling and emptying of a relatively large number of traps which were shown to exist. Several strong g10w peaks were detected above liquid nitrogen temperature. One of the peaks occurs between 0 ~ and 20~ ABSTRACTThe crystallization of calcium chloro-and chloro-fluoroapatites from calcium halide fluxes was studied as a function of composition and heating schedules. Activation of Ca5 (PO4)3F0.9C10.1 was investigated by varying phosphor stoichiometry and firing methods. The results indicate that flux-grown apatites are slightly deficient in PO43-and that for a particle size of predominantly 50-100~, 72-hr firing at 1150~ causes only limited incorporation of Sb 3+, Cd 2+, and additional PO43-. The incorporation of Mn 2+ is more extensive and may be nearly uniform. The rate of migration of Mn and Sb toward the interior of the crystals increases with increasing PO48-[as (NH4)2HPO4] added prior to activation; however, maximum emission occurs at a calculated over-all metal/phosphorus ratio of exactly 5/3. High output of heterogeneously emitting crystals suggests that quantum efficiency is independent of activator concentration. ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 130.102.42.98 Downloaded on 2015-03-13 to IP ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 130.102.42.98 Downloaded on 2015-03-13 to IP Vol. 113, No. 2 CALCIUM HALOPHOSPHATE PHOSPHORS ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 130.102.42.98 Downloaded on 2015-03-13 to IP ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 130.102.42.98 Downloaded on 2015-03-13 to IP