# Patent

## Title
Luminescent material

## Abstract

This invention relates to luminescent materials for ultraviolet light or visible light excitation containing lead and/or copper doped chemical compounds. The luminescent material is composed of one or more than one compounds of aluminate type, silicate type, antimonate type, germanate/or germanate-silicate type, and/or phosphate type. Accordingly, the present invention is a good possibility to substitute earth alkaline ions by lead and copper for a shifting of the emission bands to longer or shorter wave length, respectively. Luminescent compounds containing copper and/or lead with improved luminescent properties and also with improved stability against water, humidity as well as other polar solvents are provided. The present invention is to provide lead and/or copper doped luminescent compounds, which has high color temperature range about 2,000K to 8,000K or 10,000K and CRI over 90.

## Background
CROSS REFERENCE TO RELATED APPLICATIONS
The present application is a continuation of U.S. patent application Ser. No. 11/024,722 filed on Dec. 30, 2004, and claims priority from and the benefit of Korean Patent Application No. 10-2004-0042397 filed on Jun. 10, 2004, all of which are hereby incorporated by reference for all purposes as if fully set forth herein. This application is related to U.S. patent application Ser. No. 11/024,702, filed on Dec. 30, 2004, now issued as U.S. Pat. No. 7,554,129.


BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to fluorescent materials containing rare earth elements and more particularly to such luminescent materials for exciting ultraviolet as well as visible light containing lead and/or copper doped compounds.
2. Description of the Related Art
Lead and copper activated materials are known for short wave excitation, e.g. from a low pressure mercury lamp, such as barium disilicate activated by lead (Keith H. Butler, The Pennsylvania State University Press, 1980, S 175, orthosilicate activated by lead (Keith H. Butler, The Pennsylvania State University Press, 1980, S. 181), akermanites activated by lead, or Ca-metasilicate activated by Pb2+.
Generally, the maxima of the emission bands of such lead activated phosphors are located between 290 nm and 370 nm at 254 nm excitation. Bariumdisilicate activated by lead is an U.V. emitting phosphor which currently is used in sun parlor lamps.
Lead has in the ground state 1S0 two outer electrons. The electron configuration of the ground state is d10s2, so that the lowest excited state has d10sp configuration. The excited sp configuration has four levels, 3P0, 3P1, 3P2 and 1P1, which can be achieved between 165.57 nm (3P0) and 104.88 nm (1P1) in the free ion. Transitions between 1S0 and 1P1 excited level are allowed by all selection rules. While transitions between 1S0 and 3P0 are only allowed with the lowest symmetry, transitions between 1S0 and 3P1 as well as 3P2 are allowed only under certain conditions. However, excitation between 180 and 370 nm has the same emission. Excitation with wavelength longer than 370 nm is not possible.
Otherwise, luminescent materials are known having lead as a host lattice component. Molybdate phosphors containing MoO42− centers are described in Bernhardt, H. J., Phys. Stat. Sol. (a), 91, 643, 1985. PbMoO4 shows at room temperature red emission with an emission maximum at 620 nm under photoexcitation at 360 nm.
However, such emission is not caused by lead itself. In molybdates the luminescence properties are not caused by the metal ion M2+ (M2+MoO4 where M2+=Ca, Sr, Cd, Zn, Ba, Pb etc). Here, defect centers of MoO42− ions coupled to O2−-ion vacancies seem to be the reason. Nevertheless, the Pb2+-ion influences the preferred emission properties because it stabilizes the host lattice.
As a familiar example, tungstates (Ca,Pb)WO4 as mixed crystals have a strong green emission with high quantum output of 75% (Blasse, G, Radiationless processes in luminescent materials, in Radiationless Processes, DiBartolo, B., Ed. Plenum Press, New York, 1980, 287). Under 250 nm excitation PbWO4 shows blue emission and under 313 nm excitation PbWO4 has an orange emission band, which can be caused by Schottky defects or by impurity ions (Phosphor Handbook, edited under the Auspice of Phosphor Research Society, CRC Press New York, 1998, S 205).
Copper was used as a monovalent activator in orthophosphates (Wanmaker, W. L. and Bakker, C., J. Electrochem. Soc., 106, 1027, 1959) with an emission maximum at 490 nm. The ground state of monovalent copper is a filled shell 3d10. That is the level 1S0. After exciting the lowest excited configuration is 3d94s. This configuration has two terms, 3D and 1D. The next higher configuration, 3d94p, gives 6 terms 3P°, 3F°, 3D°, 1F°, 1D° and 1P°. The transitions between the ground state 1S0 and the 1D or 3D are forbidden by parity or spin, respectively. In copper ions, the excitation to the crystal field levels of 4p terms are allowed. Emission will be got either by a direct return from the crystal field odd state to the ground state or by a combination of transitions first from the odd state to a crystal field level and after that a second transition from these 3D or 1D state of the 3d94s configuration to the ground state.
The ground state of bivalent copper has 3d9-configuration. That is the level 2D5/2. In the bivalent copper, one of the d-electrons can be excited to the 4s or 4p orbital. The lowest exciting configuration is the 3d84s with two quartet terms 4F, 4P and four doublet terms, 2F, 2D, 2P and 2G without emission caused by forbidden transitions. The higher exciting configuration is the 3d84p-configuration with four terms 4D°, 4G°, 4F°, and 4P°, where emission can occur.
Copper activated or co-activated sulphide-phosphors are well known and they are commercial used for cathode ray tubes. The green-emitting ZnS:Cu, Al (wherein, the copper is used as activator and Al is used as co-activator) is very important in CRT applications.
In zinc-sulphide phosphors, the luminescent materials can be classified into five kinds, depending on the relative ratio of the concentration of activators and co-activators (van Gool, W., Philips Res. Rept. Suppl., 3, 1, 1961). Here, the luminescent centers are formed from deep donors or deep acceptors, or by their association at the nearest-neighbor sites (Phosphor Handbook, edited under the Auspice of Phosphor Research Society, CRC Press New York, 1998, S. 238).
Orthophosphates activated by copper (Wanmaker, W. L., and Spier, H. L., JECS 109 (1962), 109), and pyrophosphates, alumosilicates, silicates, and tripolyphosphates all activated by copper are described in “Keith H. Butler, The Pennsylvania State University Press, 1980, S. 281”. However, such phosphors can only be used for a short wave U.V. excitation. Because of their unstable chemical properties and their temperature behavior, they cannot be used in fluorescent lamps.
The influence of lead and copper ions as host lattice component in oxygen dominated compounds, activated by rare earth ions such as Eu2+, Ce3+ and others, has not been yet described. It should to be expected that the incorporation of lead and/or copper as a host lattice component influences the preferred luminescent-optical properties regarding improved luminescent intensity as well as desirable shifting of emission maxima, color points, and shape of emission spectra and stabilizing of the lattice.
The influence of lead-ions and/or copper-ions as components in the host lattice should show improved luminescent properties for excitation wavelength higher than 360 nm. In this region of wavelength, both ions do not show own radiation transfers due to the energy levels of their electron configuration, so that any kind of exciting radiation cannot be lost.
Lead and copper doped luminescent materials show improved emission intensities compared to luminescent materials having not these components in the host lattice. Furthermore, as a desirable effect of lead and copper doped luminescent materials shows a shifting of the emission wavelength to higher or to lower energies. For compounds containing lead or copper, these ions do not react as activators in broadest sense. However, the use of these ions leads to an influence on the crystal field splitting as well as the covalency.
Lead ions having an ionic radius of 119 pm can substitute the alkaline earth ions Ca having an ionic radius of 100 pm and Sr having an ionic radius of 118 pm very easily. The electro negativity of lead with 1.55 is much higher than that of Ca (1.04) and Sr (0.99). The preparation of substances containing lead is complicated due to the possibility of an oxidation of these ions in reducing atmospheres. For the preparation of lead doped compounds, which need reducing atmosphere, special preparation processes are necessary.
The influence on lead in the crystal field is shown in a generally shifting the emission characteristics depending on the substituted ions. In cases of a substitution of Pb for Sr or Ba in Eu-activated aluminates and/or silicates, the emission maximum should be shifted to longer wavelength due to smaller ionic radii of Pb compared with Ba and Sr ionic radii. That leads to a stronger crystal field in the surrounding of the activator ion.
A similar effect shows the substitution of copper for alkaline earth ions. Here, an additional influence is effective. Due to the higher ionic potential of copper as a quotient of ionic charge and ionic radius compared to the bigger alkaline earth ions, the copper ions can attract the neighboring oxygen ions stronger than the alkaline earth ions. So the substitution of the bigger alkaline earth ions Ca, Sr and Ba by copper leads to a stronger crystal field in the surrounding of the activator ions, too. Thus, the shape of emission bands can be influenced, the shifting of the emission peak to longer wavelength is connected in a broadening of the emission curves for band emission. In addition, it should be possible to increase the intensity of emission by substitution of ions copper and lead. Generally, the shifts of emission peaks to longer as well as to shorter wavelength are desirable in the field of LED lighting. Here, it is necessary to realize a fine tuning to get a special wavelength for desired color points as well as for better brightness of optical devices. By using cations, copper and lead, such a fine tuning should be possible.
It is known that some luminescent materials and phosphors are unstable in water, air humidity, water steam or polar solvents. For instance, aluminates with spinell structure or silicates with orthorhomcic as well as akermanite structures show more or less high sensitivity to water, air humidity, water steam or polar solvents due to high basicity. However, due to a higher covalency and a lower basicity, the incorporation of lead and or copper in a host lattice should improve this behavior of luminescent materials against water, air humidity and polar solvents if substituted for cations having a high basicity.
SUMMARY OF THE INVENTION
In view of the prior art described above, it is an object of the present invention to provide lead and/or copper doped luminescent materials which have a very good possibility to substitute earth alkaline ions by lead and copper with a shifting of the emission bands to longer or shorter wave length, respectively.
Another object of the present invention is to provide luminescent materials containing copper and/or lead with improved luminescent properties and also with improved stability against water, humidity as well as other polar solvents.
An additional object of the present invention is to provide lead and/or copper doped luminescent materials, which give high color temperature range about 2,000K to 8,000K or 10,000K and CRI over 90 in LED.
To achieve these and other objects, as embodied and broadly described herein, luminescent materials for ultraviolet light or visible light excitation comprises lead and/or copper doped chemical compounds containing a rare earth element or other luminescent ions.
The luminescent materials may be composed of one or more compounds of aluminate, silicate, antimonate, germanate/or germanate-silicate, and phosphate.
The aluminate is expressed as follows:

a(M′O).b(M′′2O).c(M′′X).dAl2O3.e(M′′′O).f(M′′′′2O3).g(M′′′′′oOp).h(M′′′′′′xOy) a(M′O).b(M′′2O).c(M′′X).4-a-b-c(M′′′O).7(Al2O3).d(B2O3).e(Ga2O3).f(SiO2).g(GeO2).h(M′′′′xOy) and a(M′O).b(M′′O).c(Al2O3).d(M′′′2O3).e(M′′′′O2).f(M′′′′′xOy)

The silicate is expressed as follows:

a(M′O).b(M′′O).c(M′′′X).d(M′′′O2).e(M′′′′2O3).f(M′′′′′oOp).g(SiO2).h(M′′′′′′xOy)

The antimonate is expressed as follows:

a(M′O).b(M′′2O).c(M′′X).d(Sb2O5).e(M′′′O).f(M′′′′xOy)

The germanate/or germanate-silicate is expressed as follows:

a(M′O).b(M′′2O).c(M′′X).dGeO2.e(M′′′O).f(M′′′′2O3).g(M′′′′′oOp).h(M′′′′′′xOy)

The phosphate is expressed as follows:

a(M′O).b(M′′2O).c(M′′X).dP2O5.e(M′′′O).f(M′′′′2O3).g(M′′′′′O2).h(M′′′′′′xOy)

Meanwhile, the luminescent materials may be used as a converter for the primary long-wave ultraviolet in the range of 300-400 nm and/or blue radiation in the range of 380-500 nm generated from one or more single primary elements within a light emitting device to produce light in the visible region of the spectrum up to a high color rendering index Ra>90.
Furthermore, the luminescent materials may be used in LED as a single compound and/or a mixture of a plurality of single compounds for realizing white light with a color rendering up to Ia.


DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Hereinafter, the present invention will be described in detail.
EXAMPLE 1
Luminescent materials for ultraviolet light or visible light excitation comprise lead and/or copper doped aluminates according to the formula as follows:

a(M′O).b(M′′2O).c(M′′X).dAl2O3.e(M′′′O).f(M′′′′2O3).g(M′′′′′oOp).h(M′′′′′′xOy)  (1)

wherein M′ may be Pb, Cu, and/or any combination thereof; M′′ may be one or more monovalent elements, for example, Li, Na, K, Rb, Cs, Au, Ag, and/or any combination thereof; M′′′ may be one or more divalent elements, for example, Be, Mg, Ca, Sr, Ba, Zn, Cd, Mn, and/or any combination thereof; M′′′′ may be one or more trivalent elements, for example, Sc, B, Ga, In, and/or any combination thereof; M′′′′′ may be Si, Ge, Ti, Zr, Mn, V, Nb, Ta, W, Mo, and/or any combination thereof; M′′′′′′ may be Bi, Sn, Sb, Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and/or any combination thereof; X may be F, Cl, Br, I, and/or any combination thereof; 0<a≦2; 0≦b≦2; 0≦c≦2; 0<d≦8; 0<e≦4; 0≦f≦3; 0≦g≦8; 0<h≦2; 1≦o≦2; 1≦p≦5; 1≦x≦2; and 1≦y≦5.

a(M′O).b(M′′2O).c(M′′X).4-a-b-c(M′′′O).7(Al2O3).d(B2O3).e(Ga2O3).f(SiO2).g(GeO2).h(M′′′′xOy)  (2)

wherein M′ may be Pb, Cu, and/or any combination thereof; M′′ may be one or more monovalent elements, for example, Li, Na, K, Rb, Cs, Au, Ag, and/or any combination thereof; M′′′ may be one or more divalent elements, for example, Be, Mg, Ca, Sr, Ba, Zn, Cd, Mn, and/or any combination thereof; M′′′′ may be Bi, Sn, Sb, Sc, Y, La, In, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and any combination thereof; X may be F; Cl, Br, I, and any combination thereof; 0<a≦4; 0≦b≦2; 0≦c≦2; 0≦d≦1; 0≦e≦1; 0≦f≦1; 0≦g≦1; 0<h≦2; 1≦x≦2; and 1≦y≦5.
The preparation of copper as well as lead doped luminescent materials may be a basic solid state reaction. Pure starting materials without any impurities, e.g. iron, may be used. Any starting material which may transfer into oxides via a heating process may be used to form oxygen dominated phosphors.
EXAMPLES OF PREPARATION:
Preparation of the luminescent material having formula (3)

Cu0.02Sr3.98Al14O25:Eu  (3)

Starting materials: CuO, SrCO3, Al(OH)3, Eu2O3, and/or any combination thereof.
The starting materials in the form of oxides, hydroxides, and/or carbonates may be mixed in stoichiometric proportions together with small amounts of flux, e.g., H3BO3. The mixture may be fired in an alumina crucible in a first step at about 1,200° C. for about one hour. After milling the pre-fired materials a second firing step at about 1,450° C. in a reduced atmosphere for about 4 hours may be followed. After that the material may be milled, washed, dried and sieved. The resulting luminescent material may have an emission maximum of about 494 nm.







TABLE 1







copper doped Eu2+-activated aluminate compared


with Eu2+-activated aluminate without copper 


at about 400 nm excitation wavelength










Copper doped 
Compound 



compound
without copper



Cu0.02Sr3.98Al14O25: Eu
Sr4Al14O25: Eu












Luminous density (%)
103.1
100


Wavelength (nm)
494
493









Preparation of the luminescent material having formula (4)

Pb0.05Sr3.95Al14O25:Eu  (4)

Starting materials: PbO, SrCO3, Al2O3, Eu2O3, and/or any combination thereof.
The starting materials in form of very pure oxides, carbonates, or other components which may decompose thermically into oxides, may be mixed in stoichiometric proportion together with small amounts of flux, for example, H3BO3 The mixture may be fired in an alumina crucible at about 1,200° C. for about one hour in the air. After milling the pre-fired materials a second firing step at about 1,450° C. in air for about 2 hours and in a reduced atmosphere for about 2 hours may be followed. Then the material may be milled, washed, dried, and sieved. The resulting luminescent material may have an emission maximum of from about 494.5 nm.







TABLE 2







lead doped Eu2+-activated aluminate compared 


with Eu2+-activated aluminate without lead


at about 400 nm excitation wavelength












Lead doped 
Compound 




compound
without lead




Ph0.05Sr3.95Al14O25: Eu
Sr4Al14O25: Eu







Luminous density (%)
101.4
100



Wavelength (nm)
494.5
493

















TABLE 3







optical properties of some copper and/or lead doped aluminates


excitable by long wave ultraviolet and/or by visible light and their luminous 


density in % at 400 nm excitation wavelength













Luminous






density at 
Peak





400 nm
wave





excitation 
length 
Peak wave 




compared
of lead/
length of




with copper/
copper
materials 



Possible
lead not doped
doped 
without



excitation
compounds 
materials
lead/


Composition
range(nm)
(%)
(nm)
copper(nm)














Cu0.5Sr3.5Al14O25: Eu
360-430
101.2
495
493


Cu0.02Sr3.98Al14O25: Eu
360-430
103.1
494
493


Pb0.05Sr3.95Al14O25: Eu
360-430
101.4
494.5
493


Cu0.01Sr3.99Al13.995Si0.005O25: Eu
360-430
103
494
492


Cu0.01Sr3.395Ba0.595Al14O25: Eu, Dy
360-430
100.8
494
493


Pb0.05Sr3.95Al13.95Ga0.05O25: Eu
360-430
101.5
494
494









EXAMPLE 2
Luminescent materials for ultraviolet light or visible light excitation comprise lead and/or copper doped aluminates according to the formula as follows:

a(M′O).b(M′′O).c(Al2O3).d(M′′′2O3).e(M′′′′O2).f(M′′′′′xOy)  (5)

wherein M′ may be Pb, Cu, and/or any combination thereof; M′′ may be Be, Mg, Ca, Sr, Ba, Zn, Cd, Mn, and/or any combination thereof; M′′′ may be B, Ga, In, and/or any combination thereof; M′′′′ may be Si, Ge, Ti, Zr, Hf, and/or any combination thereof; M′′′′′ may be Bi, Sn, Sb, Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and/or any combination thereof; 0<a≦1; 0≦b≦2; 0<c≦8; 0≦d≦1; 0≦e≦1; 0<f≦2; 1≦x<2; and 1≦y≦5.
The luminous peak and density of Example 2 are described in Table 7, which will be shown below.
EXAMPLE OF PREPARATION:
Preparation of the luminescent material having formula (6)

Cu0.05Sr0.95Al1.9997Si0.0003O4:Eu  (6)

Starting materials: CuO, SrCO3, Al2O3, SiO2, Eu2O3, and/or any combination thereof.
The starting materials in the form of, for example, pure oxides and/or as carbonates may be mixed in stoichiometric proportions together with small amounts of flux, for example, AlF3. The mixture may be fired in an alumina crucible at about 1,250° C. in a reduced atmosphere for about 3 hours. After that the material may be milled, washed, dried and sieved. The resulting luminescent material may have an emission maximum of about 521.5 nm.







TABLE 4







copper doped Eu 2+-activated aluminate compared 


with Eu 2+-activated aluminate without copper


at about 400 nm excitation wavelength











Compound 



Copper doped compound
without copper



Cu0.05Sr0.95Al1.9997Si0.0003O4: Eu
SrAl2O4: Eu












Luminous density (%)
106
100


Wavelength (nm)
521.5
519









Preparation of the luminescent material having formula (7)

Cu0.12BaMg1.88Al16O27:Eu  (7)

Starting materials: CuO, MgO, BaCO3, Al(OH)3, Eu2O3, and/or any combination thereof.
The starting materials in the form of, for example, pure oxides, hydroxides, and/or carbonates may be mixed in stoichiometric proportions together with small amounts of flux, for example, AlF3. The mixture may be fired in an alumina crucible at about 1,420° C. in a reduced atmosphere for about 2 hours. After that the material may be milled, washed, dried, and sieved. The resulting luminescent material may have an emission maximum of about 452 nm.







TABLE 5







copper doped Eu2+-activated aluminate compared 


with copper not doped Eu2+-activated aluminate 


at 400 nm excitation wavelength











Comparison 



Copper doped compound
without copper



Cu0.12BaMg1.88Al16O27: Eu
BaMg2Al16O27: Eu





Luminous density 
101
100


(%)




Wavelength (nm)
452
450









Preparation of the luminescent material having formula (8)

Pb0.1Sr0.9Al2O4:Eu  (8)

Starting materials: PbO, SrCO3, Al(OH)3, Eu2O3, and/or any combination thereof.
The starting materials in form of, for example, pure oxides, hydroxides, and/or carbonates may be mixed in stoichiometric proportions together with small amounts of flux, for example, H3BO3. The mixture may be fired in an alumina crucible at about 1,000° C. for about 2 hours in the air. After milling the pre-fired materials a second firing step at about 1,420° C. in the air for about 1 hour and in a reduced atmosphere for about 2 hours may be followed. After that the material may be milled, washed, dried and sieved. The resulting luminescent material may have an emission maximum of about 521 nm.







TABLE 6







lead doped Eu 2+-activated aluminate compared 


with Eu 2+-activated aluminate without lead 


at about 400 nm excitation wavelength










Lead doped 
Compound 



compound
without lead



Pb0.1Sr0.9Al2O4: Eu
SrAl2O4: Eu





Luminous density (%)
102
100


Wavelength (nm)
521
519









Results obtained in regard to copper and/or lead doped aluminates are shown in table 7.







TABLE 7







optical properties of some copper and/or lead doped aluminates


excitable by long wave ultraviolet and/or by visible light and their luminous density


in % at 400 nm excitation wavelength














Peak wave





Luminous density at
length of



Possible
400 nm excitation
lead/copper



excitation
compared with
doped
Peak wave length of



range
copper/lead not doped
materials
materials without


Composition
(nm)
compounds (%)
(nm)
lead/copper (nm)














Cu0.05Sr0.95Al1.9997Si0.0003O4:Eu
360-440
106
521.5
519


Cu0.2Mg0.7995Li0.0005Al1.9Ga0.1O4:Eu, Dy
360-440
101.2
482
480


Pb0.1Sr0.9Al2O4:Eu
360-440
102
521
519


Cu0.05BaMg1.95Al16O27:Eu, Mn
360-400
100.5
451, 515
450, 515


Cu0.12BaMg1.88Al16O27:Eu
360-400
101
452
450


Cu0.01BaMg0.99Al10O17:Eu
360-400
102.5
451
449


Pb0.1BaMg0.9Al9.5Ga0.5O17:Eu, Dy
360-400
100.8
448
450


Pb0.08Sr0.902Al2O4:Eu, Dy
360-440
102.4
521
519


Pb0.2Sr0.8Al2O4:Mn
360-440
100.8
658
655


Cu0.06Sr0.94Al2O4:Eu
360-440
102.3
521
519


Cu0.05Ba0.94Pb0.06Mg0.95Al10O17:Eu
360-440
100.4
451
449


Pb0.3Ba0.7Cu0.1Mg1.9Al16O27:Eu
360-400
100.8
452
450


Pb0.3Ba0.7Cu0.1Mg1.9Al16O27:Eu, Mn
360-400
100.4
452, 515
450, 515









EXAMPLE 3
Luminescent materials for ultraviolet light or visible light excitation comprise lead and/or copper doped silicates according to the formula as follows:

a(M′O).b(M′′O).c(M′′′X).d(M′′′2O).e(M′′′′2O3).f(M′′′′′oOp).g(SiO2).h(M′′′′′′xOy)  (9)

wherein M′ may be Pb, Cu, and/or any combination thereof; M′′ may be Be, Mg, Ca, Sr, Ba, Zn, Cd, Mn, and/or any combination thereof; M′′′ may be Li, Na, K, Rb, Cs, Au, Ag, and/or any combination thereof; M′′′′ may be Al, Ga, In, and/or any combination thereof; M′′′′′′ may be Ge, V, Nb, Ta, W, Mo, Ti, Zr, Hf, and/or any combination thereof; M′′′′′′ may be Bi, Sn, Sb, Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and/or any combination thereof; X may be F, Cl, Br, I, and any combination thereof; 0<a≦2; 0<b≦8; 0≦c≦4; 0≦d≦2; 0≦e≦2; 0≦f≦2; 0≦g≦10; 0<h≦5; 1≦o≦2; 1≦p≦5; 1≦x≦2; and 1≦y≦5.
The superior luminous density of Example 3 can be seen below.
EXAMPLE OF PREPARATION:
Preparation of the luminescent material having formula (10)

Cu0.05Sr1.7Ca0.25SiO4:Eu  (10)

Starting materials: CuO, SrCO3, CaCO3, SiO2, Eu2O3, and/or any combination thereof.
The starting materials in the form of pure oxides and/or carbonates may be mixed in stoichiometric proportions together with small amounts of flux, for example, NH4Cl. The mixture may be fired in an alumina crucible at about 1,200° C. in an inert gas atmosphere (e.g., N2 or noble gas) for about 2 hours. Then the material may be milled. After that, the material may be fired in an alumina crucible at about 1,200° C. in a slightly reduced atmosphere for about 2 hours. Then, the material may be milled, washed, dried, and sieved. The resulting luminescent material may have an emission maximum at about 592 nm.







TABLE 8







copper doped Eu2+-activated silicate compared with


Eu2+-activated silicate without copper at about


400 nm excitation wavelength











Compound



Copper doped compound
without copper



Cu0.05Sr1.7Ca0.25SiO4:Eu
Sr1.7Ca0.3SiO4:Eu













Luminous density (%)
104
100


Wavelength (nm)
592
588









Preparation of the Luminescent Material Having Formula (11):

Cu0.2Ba2Zn0.2Mg0.6Si2O7:Eu  (11)

Starting materials: CuO, BaCO3, ZnO, MgO, SiO2, Eu2O3, and/or any combination thereof.
The starting materials in the form of very pure oxides and carbonates may be mixed in stoichiometric proportions together with small amounts of flux, for example, NH4Cl. In a first step the mixture may be fired in an alumina crucible at about 1,100° C. in a reduced atmosphere for about 2 hours. Then the material may be milled. After that the material may be fired in an alumina crucible at about 1,235° C. in a reduced atmosphere for about 2 hours. Then that the material may be milled, washed, dried and sieved. The resulting luminescent material may have an emission maximum at about 467 nm.







TABLE 9







copper doped Eu2+-activated silicate compared with


Eu2+-activated silicate without copper at 400 nm


excitation wavelength











Compound



Copper doped compound
without copper



Cu0.2Sr2Zn0.2Mg0.6Si2O7:Eu
Sr2Zn2Mg0.6Si2O7:Eu













Luminous density
101.5
100


(%)


Wavelength (nm)
467
465









Preparation of the luminescent material having formula (12)

Pb0.1BaO0.95Sr0.95Si0.998Ge0.002O4:Eu  (12)

Starting materials: PbO, SrCO3, BaCO3, SiO2, GeO2, Eu2O3, and/or any combination thereof.
The starting materials in the form of oxides and/or carbonates may be mixed in stoichiometric proportions together with small amounts of flux, for example, NH4Cl. The mixture may be fired in an alumina crucible at about 1,000° C. for about 2 hours in the air. After milling the pre-fired materials a second firing step at 1,220° C. in air for 4 hours and in reducing atmosphere for 2 hours may be followed. After that the material may be milled, washed, dried and sieved. The resulting luminescent material may have an emission maximum at about 527 nm.







TABLE 10







lead doped Eu2+-activated silicate compared with Eu2+-activated


silicate without lead at about 400 nm excitation wavelength











Compound



Lead doped compound
without lead



Pb0.1Ba0.95Sr0.95Si0.998Ge0.002O4:Eu
BaSrSiO4:Eu













Luminous density
101.3
100


(%)


Wavelength (nm)
527
525









Preparation of the luminescent material having formula (13)

Pb0.25Sr3.75Si3O8Cl4:Eu  (13)

Starting materials: PbO, SrCO3, SrCl2, SiO2, Eu2O3, and any combination thereof.
The starting materials in the form of oxides, chlorides, and/or carbonates may be mixed in stoichiometric proportions together with small amounts of flux, for example, NH4Cl. The mixture may be fired in an alumina crucible in a first step at about 1,100° C. for about 2 hours in the air. After milling the pre-fired materials a second firing step at about 1,220° C. in the air for about 4 hours and in a reduced atmosphere for about 1 hour may be followed. After that the material may be milled, washed, dried and sieved. The resulting luminescent material may have an emission maximum at about 492 nm.







TABLE 11







lead doped Eu2+-activated chlorosilicate compared with


Eu2+-activated chlorosilicate without lead at 400 nm


excitation wavelength











Compound



Lead doped compound
without lead



Pb0.25Sr3.75Si3O8Cl4:Eu
Sr4Si3O8Cl4:Eu













Luminous density (%)
100.6
100


Wavelength (nm)
492
490









Results obtained with respect to copper and/or lead doped silicates are shown in table 12.







TABLE 12







optical properties of some copper and/or lead doped rare earth


activated silicates excitable by long wave ultraviolet and/or by visible light and their luminous


density in % at about 400 nm excitation wavelength













Luminous density at
Peak wave




Possible
400 nm excitation
length
Peak wave length



excitation
compared with
of lead/copper
of materials



range
copper/lead not doped
doped materials
without


Composition
(nm)
compounds (%)
(nm)
lead/copper (nm)














Pb0.1Ba0.95Sr0.95Si0.998Ge0.002O4:Eu
360-470
101.3
527
525


Cu0.02(Ba,Sr,Ca,Zn)1.98SiO4:Eu
360-500
108.2
565
560


Cu0.05Sr1.7Ca0.25SiO4:Eu
360-470
104
592
588


Cu0.05Li0.002Sr1.5Ba0.448SiO4:Gd, Eu
360-470
102.5
557
555


Cu0.2Sr2Zn0.2Mg0.6Si2O7:Eu
360-450
101.5
467
465


Cu0.02Ba2.8Sr0.2Mg0.98Si2O8:Eu, Mn
360-420
100.8
440, 660
438, 660


Pb0.25Sr3.75Si3O8Cl4:Eu
360-470
100.6
492
490


Cu0.2Ba2.2Sr0.75Pb0.05Zn0.8Si2O8:Eu
360-430
100.8
448
445


Cu0.2Ba3Mg0.8Si1.99Ge0.01O8:Eu
360-430
101
444
440


Cu0.5Zn0.5Ba2Ge0.2Si1.8O7:Eu
360-420
102.5
435
433


Cu0.8Mg0.2Ba3Si2O8:Eu, Mn
360-430
103
438, 670
435, 670


Pb0.15Ba1.84Zn0.01Si0.99Zr0.01O4:Eu
360-500
101
512
510


Cu0.2Ba5Ca2.8Si4O16:Eu
360-470
101.8
495
491









EXAMPLE 4
Luminescent materials for ultraviolet light or visible light excitation comprise lead and/or copper doped antimonates according to the formula as follows:

a(M′O).b(M′′2O).c(M′X).d(Sb2O5).e(M′′′P).f(M′′′′xOy)  (14)

wherein M′ may be Pb, Cu, and/or any combination thereof; M′′ may be Li, Na, K, Rb, Cs, Au, Ag, and/or any combination thereof; M′′′ may be Be, Mg, Ca, Sr, Ba, Zn, Cd, Mn, and/or any combination thereof; M′′′′ may be Bi, Sn, Sc, Y, La, Pr, Sm, Eu, Tb, Dy, Gd, and/or any combination thereof; X may be F, Cl, Br, I, and/or any combination thereof; 0<a≦2; 0≦b≦2; 0≦c≦4; 0≦d≦8; 0≦e≦8; 0<f≦2; 1≦x≦2; and 1≦y≦5.
EXAMPLES OF PREPARATION:
Preparation of the luminescent material having formula (15)

Cu0.2Mg1.7Li0.2Sb2O7:Mn  (15)

Starting materials: CuO, MgO, Li2O, Sb2O5, MnCO3, and/or any combination thereof.
The starting materials in the form of oxides may be mixed in stoichiometric proportion together with small amounts of flux. In a first step the mixture may be fired in an alumina crucible at about 985° C. in the air for about 2 hours. After pre-firing the material may be milled again. In a second step the mixture may be fired in an alumina crucible at about 1,200° C. in an atmosphere containing oxygen for about 8 hours. After that the material may be milled, washed, dried and sieved. The resulting luminescent material may have an emission maximum at about 626 nm.







TABLE 13







copper doped antimonate compared with antimonate without


copper at about 400 nm excitation wavelength











Comparison



Copper doped compound
without copper



Cu0.2Mg1.7Li0.2Sb2O7:Mn
Mg2Li0.2Sb2O7:Mn













Luminous density (%)
101.8
100


Wavelength (nm)
652
650









Preparation of the luminescent material having formula (16)

Pb0.006Ca0.6Sr0.394Sb2O6  (16)

Starting materials: PbO, CaCO3, SrCO3, Sb2O5, and/or any combination thereof.
The starting materials in the form of oxides and/or carbonates may be mixed in stoichiometric proportions together with small amounts of flux. In a first step the mixture may be fired in an alumina crucible at about 975° C. in the air for about 2 hours. After pre-firing the material may be milled again. In a second step the mixture may be fired in an alumina crucible at about 1,175° C. in the air for about 4 hours and then in an oxygen-containing atmosphere for about 4 hours. After that the material may be milled, washed, dried and sieved. The resulting luminescent material may have an emission maximum at about 637 nm.







TABLE 14







lead doped antimonate compared with antimonate without lead at


400 nm excitation wavelength











Compound



Lead doped compound
without lead



Pb0.006Ca0.6Sr0.394Sb2O6
Ca0.6Sr0.4Sb2O6













Luminous density (%)
102
100


Wavelength (nm)
637
638









Results obtained in respect to copper and/or lead doped antimonates are shown in table 15.







TABLE 15







optical properties of some copper and/or lead doped antimonates


excitable by long wave ultraviolet and/or by visible light and their luminous density in % at


about 400 nm excitation wavelength













Luminous density






at 400 nm

Peak wave




excitation

length of




compared with
Peak wave length
materials



Possible
copper/lead not
of lead/copper
without



excitation
doped compounds
doped materials
lead/copper


Composition
range (nm)
(%)
(nm)
(nm)














Pb0.2Mg0.002Ca1.798Sb2O6F2:Mn
360-400
102
645
649


Cu0.15Ca1.845Sr0.005Sb1.998Si0.002O7:Mn
360-400
101.5
660
658


Cu0.2Mg1.7Li0.2Sb2O7:Mn
360-400
101.8
652
650


Cu0.2Pb0.01Ca0.79Sb1.98Nb0.02O6:Mn
360-400
98.5
658
658


Cu0.01Ca1.99Sb1.9995V0.0005O7:Mn
360-400
100.5
660
657


Pb0.006Ca0.6Sr0.394Sb2O6
360-400
102
637
638


Cu0.02Ca0.9Sr0.5Ba0.4Mg0.18Sb2O7
360-400
102.5
649
645


Pb0.198Mg0.004Ca1.798Sb2O6F2
360-400
101.8
628
630









EXAMPLE 5
Luminescent materials for ultraviolet light or visible light excitation comprise lead and/or copper doped germanates and/or a germanate-silicates according to the formula as follows:

a(M′O).b(M′′2O).c(M′′X).dGeO2.e(M′′′O).f(M′′′′2O3).g(M′′′′′oOp).h(M′′′′′′xOy)  (17)

wherein M′ may be Pb, Cu, and/or any combination thereof; M′′ may be Li, Na, K, Rb, Cs, Au, Ag, and/or any combination thereof; M′ may be Be, Mg, Ca, Sr, Ba, Zn, Cd, and/or any combination thereof; M′′′′ may be Sc, Y, B, Al, La, Ga, In, and/or any combination thereof; M′′′′′ may be Si, Ti, Zr, Mn, V, Nb, Ta, W, Mo, and/or any combination thereof; M′′′′′′ may be Bi, Sn, Pr, Sm, Eu, Gd, Dy, and/or any combination thereof; X may be F, Cl, Br, I, and/or any combination thereof; 0<a≦2; 0≦b≦2; 0≦c≦10; 0<d≦10; 0≦e≦14; 0≦f≦14; 0≦g≦10; 0<h≦2; 1≦o≦2; 1≦p≦5; 1≦x≦2; and 1≦y≦5.
Example of Preparation:
Preparation of the luminescent material having formula (18)

Pb0.004Ca1.99Zn0.006Ge0.8Si0.2O4:Mn  (18)

Starting materials: PbO, CaCO3, ZnO, GeO2, SiO2, MnCO3, and/or any combination thereof,
The starting materials in the form of oxides and/or carbonates may be mixed in stoichiometric proportions together with small amounts of flux, for example, NH4Cl. In a first step the mixture may be fired in an alumina crucible at about 1,200° C. in an oxygen-containing atmosphere for about 2 hours. Then, the material may be milled again. In a second step the mixture may be fired in an alumina crucible at about 1,200° C. in oxygen containing atmosphere for about 2 hours. After that the material may be milled, washed, dried and sieved. The resulting luminescent material may have an emission maximum at about 655 nm.







TABLE 16







lead doped Mn-activated germanate compared with Mn-activated


germinate without lead at about 400 nm excitation wavelength










Copper doped compound
Comparison without copper



Pb0.004Ca1.99Zn0.006Ge0.8Si0.2O4:Mn
Ca1.99Zn0.01Ge0.8Si0.2O4:Mn













Luminous density (%)
101.5
100


Wavelength (nm)
655
657









Preparation of the luminescent material having formula (19)

Cu0.46Sr0.54Ge0.6Si0.4O3:Mn  (19)

Starting materials: CuO, SrCO3, GeO2, SiO2, MnCO3, and/or any combination thereof.
The starting materials in the form of oxides and/or carbonates may be mixed in stoichiometric proportions together with small amounts of flux, for example, NH4Cl. In a first step the mixture may be fired in an alumina crucible at about 1,100° C. in an oxygen-containing atmosphere for about 2 hours. Then, the material may be milled again. In a second step the mixture may be fired in an alumina crucible at about 1,180° C. in an oxygen-containing atmosphere for about 4 hours. After that the material may be milled, washed, dried and sieved. The resulting luminescent material may have an emission maximum at about 658 nm.







TABLE 17







copper doped Mn-activated germanate-silicate compared with


Mn-activated germanate-silicate without copper at 400 nm


excitation wavelength











Compound



Copper doped compound
without copper



Cu0.46Sr0.54Ge0.6Si0.4O3:Mn
SrGe0.6Si0.4O3:Mn













Luminous density (%)
103
100


Wavelength (nm)
658
655
















TABLE 18







optical properties of some copper and/or lead doped germanate-


silicates excitable by long wave ultraviolet and/or by visible light and their luminous density in


% at about 400 nm excitation wavelength













Luminous density at






400 nm excitation
Peak wave
Peak wave



Possible
compared with
length of
length of materials



excitation
copper/lead not
lead/copper
without



range
doped
doped
lead/copper


Composition
(nm)
compounds (%)
materials (nm)
(nm)














Pb0.004Ca1.99Zn0.006Ge0.8Si0.2O4:Mn
360-400
101.5
655
657


Pb0.002Sr0.954Ca1.044Ge0.93Si0.07O4:Mn
360-400
101.5
660
661


Cu0.46Sr0.54Ge0.6Si0.4O3:Mn
360-400
103
658
655


Cu0.002Sr0.998Ba0.99Ca0.01Si0.98Ge0.02O4:Eu
360-470
102
538
533


Cu1.45Mg26.55Ge9.4Si0.6O48:Mn
360-400
102
660
657


Cu1.2Mg26.8Ge8.9Si1.1O48:Mn
360-400
103.8
670
656


Cu4Mg20Zn4Ge5Si2.5O38F10:Mn
360-400
101.5
658
655


Pb0.001Ba0.849Zn0.05Sr1.1Ge0.04Si0.96O4:Eu
360-470
101.8
550
545


Cu0.05Mg4.95GeO6F2:Mn
360-400
100.5
655
653


Cu0.05Mg3.95GeO5.5F:Mn
360-400
100.8
657
653









EXAMPLE 6
Luminescent materials for ultraviolet light or visible light excitation comprise lead and/or copper doped phosphates according to the formula as follows:

a(M′O).b(M′′2O).c(M′′X).dP2O5.e(M′′′O).f(M′′′′2O3).g(M′′′′′O2).h(M′′′′′′xOy)  (20)

wherein M′ may be Pb, Cu, and/or any combination thereof; M′′ may be Li, Na, K, Rb, Cs, Au, Ag, and/or any combination thereof; M′′′ may be Be, Mg, Ca, Sr, Ba, Zn, Cd, Mn, and/or any combination thereof; M′′′′ may be Sc, Y, B, Al, La, Ga, In, and/or any combination thereof, M′′′′′ may be Si, Ge, Ti, Zr, Hf; V, Nb, Ta, W, Mo, and/or any combination thereof; M′′′′′′ may be Bi, Sn, Pr, Sm, Eu, Gd, Dy, Ce, Tb, and/or any combination thereof; X may be F, Cl, Br, I, and/or any combination thereof; 0<a≦2; 0≦b≦12; 0≦c≦16; 0<d≦3; 0≦e≦5; 0≦f≦3; 0≦g≦2; 0<h≦2; 1≦x≦2; and 1≦y≦5.
The luminescent materials comprising the lead and/or copper doped phosphates may be used as compounds for ultraviolet light in a light emitting device.
EXAMPLES OF PREPARATION:
Preparation of the luminescent material having formula (21)

Cu0.02Ca4.98(PO4)3Cl:Eu  (21)

Starting materials: CuO, CaCO3, Ca3(PO4)2, CaCl2, Eu2O3, and/or any combination thereof,
The starting materials in the form of oxides, phosphates, and/or carbonates and chlorides may be mixed in stoichiometric proportions together with small amounts of flux. The mixture may be fired in an alumina crucible at about 1,240° C. in reducing atmosphere for about 2 hours. After that the material may be milled, washed, dried and sieved. The luminescent material may have an emission maximum at about 450 nm.







TABLE 19







copper doped Eu2+-activated chlorophosphate compared with


Eu2+-activated chlorophosphate without copper at about


400 nm excitation wavelength











Compound



Copper doped compound
without copper



Cu0.02Ca4.98(PO4)3Cl:Eu
Ca5(PO4)3Cl:Eu













Luminous density (%)
101.5
100


Wavelength (nm)
450
447
















TABLE 20







copper and/or lead doped phosphates excitable by long wave ultraviolet


and/or by visible light and their luminous density in % at about 400 nm excitation wavelength













Luminous density at






400 nm




excitation compared
Peak wave length
Peak wave length



Possible
with copper/lead not
of lead/copper
of materials



excitation
doped compounds
doped materials
without


Composition
range (nm)
(%)
(nm)
lead/copper (nm)














Cu0.02Sr4.98(PO4)3Cl:Eu
360-410
101.5
450
447


Cu0.2Mg0.8BaP2O7:Eu, Mn
360-400
102
638
635


Pb0.5Sr1.5P1.84B0.16O6.84:Eu
360-400
102
425
420


Cu0.5Mg0.5Ba2(P,Si)2O8:Eu
360-400
101
573
570


Cu0.5Sr9.5(P,B)6O24Cl2:Eu
360-410
102
460
456


Cu0.5Ba3Sr6.5P6O24(F,Cl)2:Eu
360-410
102
443
442


Cu0.05(Ca,Sr,Ba)4.95P3O12Cl:Eu, Mn
360-410
101.5
438, 641
435, 640


Pb0.1Ba2.9P2O8:Eu
360-400
103
421
419









Lead and/or copper doped luminescent materials can be act as converter for light emitting devices, such as ultraviolet as well as blue emitting LEDs, back lights and painting pigments. They can convert the excitation wavelength from the ultraviolet and blue light to longer visible wavelength. For all color temperatures as well as for all color coordinates inside of the white light coordinates color mixture can be found. That is caused by the different emission colors corresponding to the RGB principle by using different kinds of luminescent materials.

## Claims

1. A luminescent material for an LED, comprising:
a compound including a host lattice and a luminescent ion,
wherein the host lattice comprises copper ions and oxygen, and
wherein the compound has the formula


a(M′O).b(M′′O).c(Al2O3).d(M′′′2O3).e(M′′′′O2).f(M′′′′′xOy)


wherein
M′ is Cu, or a combination of Cu and Pb;
M′′ is Be, Mg, Ca, Sr, Ba, Zn, Cd, Mn, or any combination of thereof;
M′′′ is B, Ga, In, or any combination thereof;
M′′′′ is Si, Ge, Ti, Zr, Hf, or any combination thereof;
M′′′′′ is a combination of at least one of Y, Gd, and Lu and at least one of Bi, Sn, Sb, Sc, La, Ce, Pr, Nd, Pm, Sm, Eu, Tb, Dy, Ho, Er, Tm, and Yb;
0<a≦1;
0≦b≦2;
0<c≦8;
0≦d≦1;
0≦e≦1;
0<f≦2;
1≦x≦2; and
1≦y≦5.

2. The luminescent material of claim 1, wherein the host lattice comprises lead ions.

3. The luminescent material of claim 1, wherein the luminescent ion comprises at least one element of Eu or Ce.

4. The luminescent material of claim 1, wherein the compound is suitable for emitting light upon excitation with near ultraviolet (UV) or visible light.