PHOSPHORS

Abstract

The present invention relates to europium-, cerium-, samarium- or praseodymium-doped boronitrides, to a process for the preparation of these compounds, and to the use of the doped boronitrides according to the invention as conversion phosphors. The present invention furthermore relates to a light source which contains a doped boronitride according to the invention.

Claims

1. Compound of the formula (1) which is doped with europium, cerium, samarium and/or praseodymium, where the degree of doping is up to 10 mol %,
A.sub.a(EA).sub.b(Ln).sub.cB.sub.eN.sub.2e+fO.sub.g(BNO).sub.h(Hal).sub.i  formula (1) where the following applies to the symbols and indices used: A are one or more elements selected from the group consisting of Li, Na and K; EA are one or more elements selected from the group consisting of Mg, Ca, Sr and Ba; Ln are one or more elements selected from the group consisting of Sc, Y, La, Gd and Lu; Hal are one or more elements selected from the group consisting of F, Cl, Br and I; 0≦a≦3; 0≦b≦5; 0≦c≦6; 1≦e≦4; 0≦f≦2; 0≦g≦6; 0≦h≦1; 0≦i≦1; where the following applies to the indices:
a+2b+3c=3e+3f+2g+2h+i;
2≦a+b+c≦6;
2≦e+f+g+h+i≦6; the compound Ca.sub.2BN.sub.2F:Eu is excluded from the invention.

2. Compound according to claim 1, characterised in that the compound is doped with Eu.sup.2+ or Eu.sup.3+, where Eu.sup.2+ replaces two alkali metals A or one alkaline-earth metal EA or Eu.sup.3+ replaces one lanthanoid metal Ln, or in that the compound is doped with Ce.sup.3+, where Ce.sup.3+ replaces one alkaline-earth metal EA or one lanthanoid metal Ln, or in that the compound is doped with Sm.sup.2+ or Sm.sup.3+, where Sm.sup.2+ replaces two alkali metals A or one alkaline-earth metal EA or Sm.sup.3+ replaces one lanthanoid metal Ln, or in that the compound is doped with Pr.sup.3+, where Pr.sup.3+ replaces one alkaline-earth metal EA or one lanthanoid metal Ln.

3. Compound according to claim 1, characterised in that the compound contains precisely one dopant, where the proportion of the dopant is 0.1 to 5 mol %.

4. Compound according to claim 1, characterised in that the boron-containing unit stands for BN.sub.2 and the index e stands for 1, 2, 3 or 4.

5. Compound according to claim 1 which is doped with europium, cerium, samarium or praseodymium, where the degree of doping is up to 10 mol %, of the formula (2),
(EA).sub.b(Ln).sub.c(BN.sub.2).sub.eN.sub.fO.sub.g(BNO).sub.h  formula (2) where EA and Ln have the meanings given in claim 1 and the following applies to the indices used: 0≦b≦4; 0≦c≦6; 1≦e≦4; 0≦f≦3; 0≦g≦6; 0≦h≦1; where the following applies to the indices:
2b+3c=3e+3f+2g+2h; with the proviso that a maximum of one of indices f, g and h is >0.

6. Compound according to claim 5, selected from the compounds (2-Eu) and (2-Ce) and (2-Sm-a) and (2-Sm-b) and (2-Pr),
(EA).sub.b-x(Ln).sub.c(BN.sub.2).sub.eN.sub.fO.sub.g(BNO).sub.h:Eu.sub.x  formula (2-Eu)
(EA).sub.b(Ln).sub.c-y(BN.sub.2).sub.eN.sub.fO.sub.g(BNO).sub.h:Ce.sub.y  formula (2-Ce)
(EA).sub.b-x(Ln).sub.c(BN.sub.2).sub.eN.sub.fO.sub.g(BNO).sub.h:Sm.sub.x  formula (2-Sm-a)
(EA).sub.b(Ln).sub.c-y(BN.sub.2).sub.eN.sub.fO.sub.g(BNO).sub.h:Sm.sub.y  formula (2-Sm-b)
(EA).sub.b(Ln).sub.c-y(BN.sub.2).sub.eN.sub.fO.sub.g(BNO).sub.h:Pr.sub.y  formula (2-Pr) where the symbols and indices used have the meanings given in claim 5 and furthermore: 0≦x≦0.05; 0≦y≦0.05; b>x in formulae (2-Eu) and (2-Sm-a); c>y in formulae (2-Ce), (2-Sm-b) and (2-Pr).

7. Compound according to claim 1, selected from the compounds of the formulae (2A) to (2R), each of which is doped with europium, cerium, samarium or praseodymium, where the degree of doping is up to 10 mol %,
(EA).sub.4,5(BN.sub.2).sub.3  formula (2A)
(EA).sub.3(BN.sub.2).sub.2-fN.sub.f  formula (2B)
(Ln).sub.3(BN.sub.2).sub.3  formula (2C)
(EA).sub.3(Ln).sub.2(BN.sub.2).sub.4  formula (2D)
(EA)(Ln).sub.3(BN.sub.2).sub.3(BNO)  formula (2E)
(EA).sub.3(Ln).sub.2(BN.sub.2).sub.2  formula (2F)
(EA).sub.3(Ln)(BN.sub.2).sub.3  formula (2G)
(Ln).sub.3(BN.sub.2)O.sub.3  formula (2H)
A(EA).sub.4(BN.sub.2).sub.3  formula (2I)
(EA).sub.4(BN.sub.2).sub.2O  formula (2J)
(EA).sub.6BN.sub.5  formula (2K)
A(EA).sub.4(BN.sub.2).sub.3  formula (2L)
(EA).sub.2(BN.sub.2)(Hal)  formula (2M)
(Ln).sub.6(BN.sub.3)O.sub.6  formula (2N)
(Ln).sub.5(B.sub.4N.sub.9)  formula (2O)
(Ln).sub.6(B.sub.4N.sub.10)  formula (2P)
(Ln).sub.4(B.sub.2N.sub.5)  formula (2Q)
(Ln).sub.5(B.sub.2N.sub.6)  formula (2R), where the symbols and indices used have the meanings given in claim 1.

8. Compound according to claim 1, selected from the compounds (2A-Eu) to (2R-Pr),
(EA).sub.4,5-x(BN.sub.2).sub.3:Eu.sub.x  formula (2A-Eu)
(EA).sub.4,5(BN.sub.2).sub.3:Ce  formula (2A-Ce)
(EA).sub.4,5-x(BN.sub.2).sub.3:Sm.sub.x  formula (2A-Sm)
(EA).sub.3-x(BN.sub.2).sub.2-fN.sub.f:Eu.sub.x  formula (2B-Eu)
(EA).sub.3(BN.sub.2).sub.2-fN.sub.f:Ce  formula (2B-Ce)
(EA).sub.3-x(BN.sub.2).sub.2-fN.sub.f: Sm.sub.x  formula (2B-Sm)
(Ln).sub.3-y(BN.sub.2).sub.3:Ce.sub.y  formula (2C-Ce)
(Ln).sub.3-y(BN.sub.2).sub.3:Sm.sub.y  formula (2C-Sm)
(Ln).sub.3-y(BN.sub.2).sub.3:Pr.sub.y  formula (2C-Pr)
(EA).sub.3-x(Ln).sub.2(BN.sub.2).sub.4:Eu.sub.x  formula (2D-Eu)
(EA).sub.3-x(Ln).sub.2(BN.sub.2).sub.4:Sm.sub.x  formula (2D-Sm-a)
(EA).sub.3(Ln).sub.2-y(BN.sub.2).sub.4:Ce.sub.y  formula (2D-Ce)
(EA).sub.3(Ln).sub.2-y(BN.sub.2).sub.4:Sm.sub.y  formula (2D-Sm-b)
(EA).sub.3(Ln).sub.2-y(BN.sub.2).sub.4:Pr.sub.y  formula (2D-Pr)
(EA).sub.1-x(Ln).sub.3(BN.sub.2).sub.3(BNO):Eu.sub.x  formula (2E-Eu)
(EA).sub.1-x(Ln).sub.3(BN.sub.2).sub.3(BNO):Sm.sub.x  formula (2E-Sm-a)
(EA)(Ln).sub.3-y(BN.sub.2).sub.3(BNO):Ce.sub.y  formula (2E-Ce)
(EA)(Ln).sub.3-y(BN.sub.2).sub.3(BNO):Sm.sub.y  formula (2E-Sm-b)
(EA)(Ln).sub.3-y(BN.sub.2).sub.3(BNO):Pr.sub.y  formula (2E-Pr)
(EA).sub.3-x(Ln).sub.2(BN.sub.2).sub.2:Eu.sub.x  formula (2F-Eu)
(EA).sub.3-x(Ln).sub.2(BN.sub.2).sub.2:Sm.sub.x  formula (2F-Sm-a)
(EA).sub.3(Ln).sub.2-y(BN.sub.2).sub.2:Ce.sub.y  formula (2F-Ce)
(EA).sub.3(Ln).sub.2-y(BN.sub.2).sub.2:Sm.sub.y  formula (2F-Sm-b)
(EA).sub.3(Ln).sub.2-y(BN.sub.2).sub.2:Pr.sub.y  formula (2F-Pr)
(EA).sub.3-x(Ln)(BN.sub.2).sub.3:Eu.sub.x  formula (2G-Eu)
(EA).sub.3-x(Ln)(BN.sub.2).sub.3:Sm.sub.x  formula (2G-Sm-a)
(EA).sub.3(Ln).sub.1-y(BN.sub.2).sub.3:Ce.sub.y  formula (2G-Ce)
(EA).sub.3(Ln).sub.1-y(BN.sub.2).sub.3:Sm.sub.y  formula (2G-Sm-b)
(EA).sub.3(Ln).sub.1-y(BN.sub.2).sub.3:Pr.sub.y  formula (2G-Pr)
(Ln).sub.3-y(BN.sub.2)O.sub.3:Ce.sub.y  formula (2H-Ce)
(Ln).sub.3-y(BN.sub.2)O.sub.3:Sm.sub.y  formula (2H-Sm)
(Ln).sub.3-y(BN.sub.2)O.sub.3:Pr.sub.y  formula (2H-Pr)
A(EA).sub.4(BN.sub.2).sub.3:Eu.sub.x  formula (2I-Eu)
A(EA).sub.4-x(BN.sub.2).sub.3:Sm.sub.x  formula (2I-Sm)
(EA).sub.4-x(BN.sub.2).sub.2O:Eu.sub.x  formula (2J-Eu)
(EA).sub.4-x(BN.sub.2).sub.2O:Sm.sub.x  formula (2J-Sm)
(EA).sub.6-x,BN.sub.5:Eu.sub.x  formula (2K-Eu)
(EA).sub.6-x,BN.sub.5:Sm.sub.x  formula (2K-Sm)
A(EA).sub.4-x(BN.sub.2).sub.3:Eu.sub.x  formula (2L-Eu)
A(EA).sub.4-x(BN.sub.2).sub.3:Sm.sub.x  formula (2L-Sm)
(EA).sub.2-x(BN.sub.2)(Hal):Eu.sub.x  formula (2M-Eu)
(EA).sub.2-x(BN.sub.2)(Hal):Sm.sub.x  formula (2M-Sm)
(Ln).sub.6-y(BN.sub.3)O.sub.6:Ce.sub.y  formula (2N-Ce)
(Ln).sub.6-y(BN.sub.3)O.sub.6:Sm.sub.y  formula (2N-Sm)
(Ln).sub.6-y(BN.sub.3)O.sub.6:Pr.sub.y  formula (2N-Pr)
(Ln).sub.5-y(B.sub.4N.sub.9):Ce.sub.y  formula (2O-Ce)
(Ln).sub.5-y(B.sub.4N.sub.9):Sm.sub.y  formula (2O-Sm)
(Ln).sub.5-y(B.sub.4N.sub.9):Pr.sub.y  formula (2O-Pr)
(Ln).sub.6-y(B.sub.4N.sub.10):Ce.sub.y  formula (2P-Ce)
(Ln).sub.6-y(B.sub.4N.sub.10):Sm.sub.y  formula (2P-Sm)
(Ln).sub.6-y(B.sub.4N.sub.10):Pr.sub.y  formula (2P-Pr)
(Ln).sub.4-y(B.sub.2N.sub.5):Ce.sub.y  formula (2Q-Ce)
(Ln).sub.4-y(B.sub.2N.sub.5):Sm.sub.y  formula (2Q-Sm)
(Ln).sub.4-y(B.sub.2N.sub.5):Pr.sub.y  formula (2Q-Pr)
(Ln).sub.5-y(B.sub.2N.sub.6):Ce.sub.y  formula (2R-Ce)
(Ln).sub.5-y(B.sub.2N.sub.6):Sm.sub.y  formula (2R-Sm)
(Ln).sub.5-y(B.sub.2N.sub.6):Pr.sub.y  formula (2R-Pr), where 0≦x≦0.05; 0≦y≦0.05; b>x in formulae (2-Eu) and (2-Sm-a); c>y in formulae (2-Ce), (2-Sm-b) and (2-Pr).

9. Compound according to claim 1, characterised in that A is selected, identically or differently, from Li and Na and in that EA is selected, identically or differently, from Ca, Sr and Ba and in that Ln is selected, identically or differently, from Y, Lu and Gd and in that Hal is selected, identically or differently, from F and Cl.

10. Compound according to claim 1, characterised in that A is equal to Li and in that EA is selected, identically or differently, from Sr and Ba and in that Ln is selected, identically or differently, from Y, Lu and Gd and in that Hal is equal to F.

11. Compound according to claim 1, characterised in that the compound has a coating on the surface.

12. Process for the preparation of a compound according to the invention according to claim 1, characterised by the following process steps: a) preparation of a mixture comprising a nitride of one or more of the cations A, EA and/or Ln, where the symbols have the meanings given in claim 1, in addition boron nitride and a europium, cerium, samarium and/or praseodymium source; b) calcination of the mixture under non-oxidising conditions.

13. A phosphor which comprises a compound according to claim 1.

14. Light source comprising a primary light source and at least one compound according to claim 1.

15. Light source according to claim 14, characterised in that it is a phosphor-converted LED.

Description

EXAMPLES

General Procedure for the Measurement of the Emission

[0087] The powder emission spectra are measured by the following general method: a loose phosphor powder bed having a depth of 5 mm whose surface has been smoothed using a glass plate is irradiated at a wavelength of 450 nm in the integration sphere of an Edinburgh Instruments FL 920 fluorescence spectrometer having a xenon lamp as excitation light source, and the intensity of the emitted fluorescence radiation is measured in a range from 465 nm to 800 nm in 1 nm steps.

Example 1: Mg.SUB.3.(BN.SUB.2.)N:Eu.SUP.2+ (1%)

[0088] 2.3982 g (23.76 mmol) of Mg.sub.3N.sub.2, 0.5903 g (23.79 mmol) of BN and 0.0118 g (0.07 mmol) of EuN are thoroughly mixed with one another in a glove box. The resultant mixture is transferred into a BN crucible and heated at 1100° C. for 6 h under a mixture of N.sub.2/H.sub.2 (95%/5%).

Example 2: Ca.SUB.3.(BN.SUB.2.).SUB.2.:Eu.SUP.2+ (1%)

[0089] 2.2175 g (14.96 mmol) of Ca.sub.3N.sub.2, 0.7642 g (30.07 mmol) of BN and 0.0374 g (0.23 mmol) of EuN are thoroughly mixed with one another in a glove box. The resultant mixture is transferred into a BN crucible and heated at 1600° C. for 8 h under a mixture of N.sub.2/H.sub.2 (95%/5%).

Example 3: Sr.SUB.3.(BN.SUB.2.).SUB.2.: Eu.SUP.2+ (1%)

[0090] 2.5228 g (8.67 mmol) of Sr.sub.3N.sub.2, 0.4348 g (17.52 mmol) of BN and 0.0405 g (0.26 mmol) of EuH.sub.2 are triturated intimately in a mortar. The starting-material mixture is subsequently transferred into a BN crucible and heated at 800° C. for 8 h under N.sub.2/H.sub.2. All manipulations of the starting materials are carried out in an N.sub.2-filled glove box.

Example 4: SrBa.SUB.8.(BN.SUB.2.).SUB.6.: Ce.SUP.3+ (1%)

[0091] 0.2028 g (0.70 mmol) of Sr.sub.3N.sub.2, 2.4794 g (5.63 mmol) of Ba.sub.3N.sub.2, 0.3147 g (12.68 mmol) of BN and 0.0033 g (0.02 mmol) of CeN are triturated intimately in a mortar. The starting-material mixture is subsequently transferred into a BN crucible and heated at 1000° C. for 8 h under N.sub.2/H.sub.2. All manipulations of the starting materials are carried out in an N.sub.2-filled glove box.

Example 5: SrBa.SUB.8.(BN.SUB.2.).SUB.6.: Pr.SUP.3+ (1%)

[0092] 0.2028 g (0.70 mmol) of Sr.sub.3N.sub.2, 2.4793 g (5.63 mmol) of Ba.sub.3N.sub.2, 0.3147 g (12.68 mmol) of BN and 0.0033 g (0.02 mmol) of PrN are triturated intimately in a mortar. The starting-material mixture is subsequently transferred into a BN crucible and heated at 1000° C. for 8 h under N.sub.2/H.sub.2. All manipulations of the starting materials are carried out in an N.sub.2-filled glove box.

Example 6: SrBN.SUB.2.F: Eu.SUP.2+ (1%)

[0093] 1.2288 g (4.22 mmol) of Sr.sub.3N.sub.2, 0.2118 g (8.53 mmol) of BN, 0.0283 g (0.17 mmol) of EuN and 0.5360 g (4.27 mmol) of SrF.sub.2 are triturated intimately in a mortar. The starting-material mixture is subsequently transferred into a BN crucible and heated at 900° C. for 6 h under N.sub.2/H.sub.2. All manipulations of the starting materials are carried out in an N.sub.2-filled glove box.

Example 7: LED Examples

[0094] General Procedure for the Construction and Measurement of pcLEDs

[0095] A mass m.sub.p (in g) of the phosphor shown in the respective LED example is weighed out, mixed with m.sub.silicone (in g) of an optically transparent silicone and subsequently mixed in a planetary centrifugal mixer to give a homogeneous mixture, so that the phosphor concentration in the overall mass is c.sub.p (in wt. %). The silicone/phosphor mixture obtained in this way is applied to the chip of a near-UV semiconductor LED with the aid of an automatic dispenser and cured with supply of heat. The near-UV semiconductor LEDs used for the LED characterisation in the present examples have an emission wavelength of 407 nm and are operated at a current strength of 350 mA. The photometric characterisation of the LED is carried out using an Instrument Systems CAS 140 spectrometer and an attached ISP 250 integration sphere. The LED is characterised via determination of the wavelength-dependent spectral power density. The resultant spectrum of the light emitted by the LED is used to calculate the colour point coordinates CIE x and y.

LED Examples with Phosphors According to the Invention

[0096] The starting weights of the individual components (phosphor and silicone) and the results of the measurements of the wavelength-dependent spectral power density in accordance with the general procedure indicated above for the construction and measurement of pc-LEDs are summarised in Table 1.

TABLE-US-00001 TABLE 1 Results of the LEDs according to the invention LED Example a LED Example b LED Example c LED Example d Parameter SrBa.sub.8(BN.sub.2).sub.6:Pr.sup.3+ SrBa.sub.8(BN.sub.2).sub.6:Ce.sup.3+ Ca.sub.3(BN.sub.2).sub.2:Eu.sup.2+ Mg.sub.3BN.sub.3:Eu.sup.2+ Phosphor (from Example 5) (from Example 4) (from Example 2) (from Example 1) M.sub.Phosphor/g 0.350 0.350 0.350 0.350 M.sub.silicone 0.650 0.650 0.650 0.650 C.sub.phosphor/wt. % 35 35 35 35 CIE 1931 x 0.468 0.458 0.527 0.498 CIE 1931 y 0.206 0.355 0.242 0.413

DESCRIPTION OF THE FIGURES

[0097] FIG. 1: XRD of Mg.sub.3(BN.sub.2)N:Eu.sup.2+ from Example 1

[0098] FIG. 2: Reflection spectrum of Mg.sub.3(BN.sub.2)N:Eu.sup.2+ from Example 1

[0099] FIG. 3: Excitation spectrum of Mg.sub.3(BN.sub.2)N:Eu.sup.2+ from Example 1

[0100] FIG. 4: Emission spectrum of Mg.sub.3(BN.sub.2)N:Eu.sup.2+ from Example 1

[0101] FIG. 5: XRD of Ca.sub.3(BN.sub.2).sub.2:Eu.sup.2+ from Example 2

[0102] FIG. 6: Reflection spectrum of Ca.sub.3(BN.sub.2).sub.2:Eu.sup.2+ from Example 2

[0103] FIG. 7: Excitation spectrum of Ca.sub.3(BN.sub.2).sub.2:Eu.sup.2+ from Example 2

[0104] FIG. 8: Emission spectrum of Ca.sub.3(BN.sub.2).sub.2:Eu.sup.2+ from Example 2

[0105] FIG. 9: X-ray powder diffraction pattern of Sr.sub.3(BN.sub.2).sub.2:Eu.sup.2+ from Ex. 3

[0106] FIG. 10: Emission spectrum of Sr.sub.3(BN.sub.2).sub.2:Eu.sup.2+ from Example 3

[0107] FIG. 11: Excitation spectrum of Sr.sub.3(BN.sub.2).sub.2:Eu.sup.2+ from Example 3

[0108] FIG. 12: Reflection spectrum of Sr.sub.3(BN.sub.2).sub.2:Eu.sup.2+ from Example 3

[0109] FIG. 13: X-ray powder diffraction pattern of SrBa.sub.8(BN.sub.2).sub.6:Ce.sup.3+ from Ex. 4

[0110] FIG. 14: Emission spectrum of SrBa.sub.8(BN.sub.2).sub.6:Ce.sup.3+ from Example 4

[0111] FIG. 15: Excitation spectrum of SrBa.sub.8(BN.sub.2).sub.6:Ce.sup.3+ from Example 4

[0112] FIG. 16: Reflection spectrum of SrBa.sub.8(BN.sub.2).sub.6:Ce.sup.3+ from Example 4

[0113] FIG. 17: X-ray powder diffraction pattern of SrBa.sub.8(BN.sub.2).sub.6:Pr.sup.3+ from Example 5

[0114] FIG. 18: Emission spectrum of SrBa.sub.8(BN.sub.2).sub.6:Pr.sup.3+ from Example 5

[0115] FIG. 19: Excitation spectrum of SrBa.sub.8(BN.sub.2).sub.6:Pr.sup.3+ from Example 5

[0116] FIG. 20: Reflection spectrum of SrBa.sub.8(BN.sub.2).sub.6:Pr.sup.3+ from Example 5

[0117] FIG. 21: X-ray powder diffraction pattern of Sr.sub.2BN.sub.2F:Eu.sup.2+ from Example 6

[0118] FIG. 22: Emission spectrum of Sr.sub.2BN.sub.2F:Eu.sup.2+ from Example 6

[0119] FIG. 23: Excitation spectrum of Sr.sub.2BN.sub.2F:Eu.sup.2+ from Example 6

[0120] FIG. 24: Reflection spectrum of Sr.sub.2BN.sub.2F:Eu.sup.2+ from Example 6

[0121] FIG. 25: LED Example a with the phosphor from Example 5

[0122] FIG. 26: LED Example b with the phosphor from Example 4

[0123] FIG. 27: LED Example c with the phosphor from Example 2

[0124] FIG. 28: LED Example d with the phosphor from Example 1