Patent Application
20170306223
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 compounds according to the invention as conversion phosphors. The present invention furthermore relates to a light-emitting device which contains a doped boronitride according to the invention.
Inorganic fluorescent powders which can be excited in the blue and/or UV spectral region have major importance as conversion phosphors for phosphor-converted LEDs, pc-LEDs for short. In the meantime, many conversion phosphor systems are known, such as, for example, alkaline-earth metal orthosilicates, thiogallates, garnets, nitrides and oxynitrides, each doped with Ce3+ or Eu2+. The last-mentioned nitride and oxynitride phosphors in particular are currently the subject of intensive research, since these materials exhibit red emission with emission wavelengths above 600 nm and are therefore of importance for the production of warm-white pc-LEDs having colour temperatures <4000 K.
A disadvantage on use of the above-mentioned phosphors for phosphor-converted LEDs is ageing at the phosphor/polymer interface, meaning that darkening of the converter layer and thus a decrease in brightness occurs. This is critical, in particular, for achieving very long lifetimes, since the encapsulation of the powder or ceramic converters takes place by means of epoxy or silicone resin. Unfortunately, both polymers are not diffusion-impermeable for small molecules such as H2O, CO2 or NH3. These thus reach the converter during the operating time of the LED lamps and can initiate (photo)chemical reactions at the interfaces there. It is therefore of particular interest to find materials which have particularly high long-term stability, as is the case, for example, in the case of Si3N4, SiC or BN. However, such materials are frequently particularly difficult to prepare.
It would therefore be desirable to have available phosphors which have higher long-term stability. A further object on which the present application is based is the provision of further phosphors, in particular orange- to red-emitting phosphors, in order to provide the person skilled in the art with a greater choice of suitable phosphors for use in phosphor-converted LEDs. The object of the present invention was therefore to provide phosphors of this type.
Surprisingly, it has been found that the europium-, cerium-, samarium- and/or praseodymium-doped boronitrides described below achieve this object and are very highly suitable for use in phosphor-converted LEDs.
Z. Kristallogr. NCS. 220 (2005), 303-304 describes the crystal structure of EuBa8(BN2)6, which can formally also be described stoichiometrically as Eu0.5Ba4(BN2)3. Luminescence properties of this compound are not described, neither is the use of this compound in a phosphor-converted LED. This compound is described as a black, air- and water-sensitive compound, meaning that it is not suitable for use as phosphor.
Journal of Solid State Chemistry 182 (2009), 3299-3304 discloses the synthesis and luminescence properties of Eu2+-activated Ca2BN2F. The compound is described here as emitting deep blue. This compound is thus not suitable as orange- to red-emitting phosphor.
The invention relates to a europium-, cerium-, samarium- and/or praseodymium-doped compound, where the dopant is present in an amount of up to 10 mol %, of the following formula (1),
Aa(EA)b(Ln)cBeN2e+fOg(BNO)h(Hal)i formula (1)
in which the following applies to the symbols and indices used:
a+2b+3c=3e+3f+2g+2h+i;
2≦a+b+c≦6;
2≦e+f+g+h+i≦6;
The prerequisite a+2b+3c=3e+3f+2g+2h+i, as defined above, results in the compound being a charge-neutral compound.
B, N and O in formula (1) stand, in accordance with conventional chemical nomenclature, for boron, nitrogen and oxygen respectively.
The compounds according to the invention are boronitrides which contain boron and at least double the stoichiometric number of nitrogen atoms. The units which contain boron and nitrogen here are (BN2)3− units, which may also be in the form of a dimer (B2N4)6− or trimer (B3N6)9−, or (BN3)6− units.
If the compound is doped with Eu, the Eu is in the form of Eu2+ or Eu3+, where Eu2+ replaces either two alkali metals A or one alkaline-earth metal EA, preferably one alkaline-earth metal EA, or Eu3+ replaces one lanthanoid metal Ln.
If the compound is doped with Ce, the Ce is in the form of Ce3+ and replaces one alkaline-earth metal EA or preferably one lanthanoid metal Ln. If the compound is doped with Sm, the Sm is in the form of Sm2+ or Sm3+, where Sm2+ replaces either two alkali metals A or one alkaline-earth metal EA, preferably one alkaline-earth metal EA, or Sm3+ replaces one lanthanoid metal Ln.
If the compound is doped with Pr, the Pr is in the form of Pr3+ and replaces one alkaline-earth metal EA or preferably one lanthanoid metal Ln.
As described above, the dopant (=activator), i.e. Eu, Ce, Sm and/or Pr, is present in a total amount of up to 10 mol %. The amount of up to 10 mol % here means that the dopant is present in an amount of up to 10 mol %, based on the element into whose lattice sites the dopant is incorporated and that replaces it in the compound. If the compound is thus doped, for example, with Eu2+ and the Eu2+ is incorporated into the lattice sites of alkaline-earth metal ions in the compound, the amount of Eu2+ ions, based on the total amount of alkaline-earth metal ions and Eu2+ ions, is a maximum of 10%.
In a preferred embodiment of the invention, the compound according to the invention contains precisely one dopant (activator), i.e. is doped either with Eu or with Ce or with Sm or with Pr, where the proportion of the dopant is up to 10 mol %. The proportion is preferably 0.1 to 5 mol %, particularly preferably 0.5 to 2 mol %, very particularly preferably 0.8 to 1.2 mol %.
In a preferred embodiment of the invention, at least one of the indices a, b and c=0. The compound according to the invention thus particularly preferably contains cations from a maximum of two of the three groups A, EA and Ln. The compound according to the invention particularly preferably contains cations from the group EA and/or Ln. a is thus particularly preferably=0.
In a further preferred embodiment of the invention, the indices a, b, c, e, f, g, h and i each stand for integers, where a deviation therefrom is possible for a, b or c if the corresponding cation has in each case been replaced by the doping with Eu or Ce or Sm or Pr.
If the boron-containing unit of the compound according to the invention stands for BN2, e then preferably stands for 1, 2, 3 or 4, particularly preferably for 2 or 3.
In a preferred embodiment of the invention, Hal=F. In a particularly preferred embodiment, i=0, and the compound according to the invention contains no halide Hal.
Preferred embodiments of the compounds according to the invention in which the boron-containing unit stands for BN2 are the europium-, cerium-, samarium- or praseodymium-doped compounds of the following formula (2), where the dopant is present in an amount of up to 10 mol %,
(EA)b(Ln)b(BN2)eNfOg(BNO)h formula (2)
where EA and Ln have the meanings given above and the following applies to the indices used:
0≦g≦6, preferably 0≦g≦3;
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.
Preferred embodiments of the above-mentioned compound of the formula (2) are the compounds (2-Eu) and (2-Ce) and (2-Sm-a) and (2-Sm-b) and (2-Pr),
(EA)b-x(Ln)b(BN2)eNfOg(BNO)h:Eux formula (2-Eu)
(EA)b(Ln)c-y(BN2)eNfOg(BNO)h:Cey formula (2-Ce)
(EA)b-x(Ln)c(BN2)eNfOg(BNO)h:Smx formula (2-Sm-a)
(EA)b(Ln)c-y(BN2)eNfOg(BNO)h:Smy formula (2-Sm-b)
(EA)b(Ln)c-y(BN2)eNfOg(BNO)h:Pry formula (2-Pr)
where the symbols and indices used have the meanings given for formula (2) and furthermore:
Preferred embodiments of the compounds of the formula (2) are the europium-, cerium-, samarium- or praseodymium-doped compounds of the following formulae (2A) to (2R),
(EA)4,5(BN2)3 formula (2A)
(EA)3(BN2)2-fNf formula (2B)
(Ln)3(BN2)3 formula (2C)
(EA)3(Ln)2(BN2)4 formula (2D)
(EA)(Ln)3(BN2)3(BNO) formula (2E)
(EA)3(Ln)2(BN2)2 formula (2F)
(EA)3(Ln)(BN2)3 formula (2G)
(Ln)3(BN2)O3 formula (2H)
A(EA)4(BN2)3 formula (2I)
(EA)4(BN2)2O formula (2J)
(EA)6BN5 formula (2K)
A(EA)4(BN2)3 formula (2L)
(EA)2(BN2)(Hal) formula (2M)
(Ln)6(BN3)O6 formula (2N)
(Ln)5(B4N9) formula (2O)
(Ln)6(B4N10) formula (2P)
(Ln)4(B2N5) formula (2Q)
(Ln)5(B2N6) formula (2R),
where the symbols and indices used have the meanings given above.
The BN2 units here for f>0, in particular for f=1, in formula (2B) can either be in the form of a separate BN2 unit together with a separate N or in the form of a 6N3 unit.
Furthermore, the BN2 units, for example in formulae (2A), (2B), (2C) and (2G), can either be in the form of three separate BN2 units or in the form of one B3N6 unit. Furthermore, the BN2 units, for example in formula (2F), can either be in the form of two separate BN2 units or in the form of one B2N4 unit.
Particularly preferred embodiments are the following compounds (2A-Eu) to (2R-Pr),
(EA)4,5-x(BN2)3:Eux formula (2A-Eu)
(EA)4,5(BN2)3:Ce formula (2A-Ce)
(EA)4,5-x(BN2)3:Smx formula (2A-Sm)
(EA)3-x(BN2)2-fNf:Eux formula (2B-Eu)
(EA)3(BN2)2-fNf:Ce formula (2B-Ce)
(EA)3-x(BN2)2-fNf:Smx formula (2B-Sm)
(Ln)3-y(BN2)3:Cey formula (2C-Ce)
(Ln)3-y(BN2)3:Smy formula (2C-Sm)
(Ln)3-y(BN2)3:Pry formula (2C-Pr)
(EA)3-x(Ln)2(BN2)4:Eux formula (2D-Eu)
(EA)3-x(Ln)2(BN2)4:Smx formula (2D-Sm-a)
(EA)3(Ln)2-y(BN2)4:Cey formula (2D-Ce)
(EA)3(Ln)2-y(BN2)4:Smy formula (2D-Sm-b)
(EA)3(Ln)2-y(BN2)4:Pry formula (2D-Pr)
(EA)1-x(Ln)3(BN2)3(BNO):Eux formula (2E-Eu)
(EA)1-x(Ln)3(BN2)3(BNO):Smx formula (2E-Sm-a)
(EA)(Ln)3-y(BN2)3(BNO):Cey formula (2E-Ce)
(EA)(Ln)3-y(BN2)3(BNO):Smy formula (2E-Sm-b)
(EA)(Ln)3-y(BN2)3(BNO):Pry formula (2E-Pr)
(EA)3-x(Ln)2(BN2)2:Eux formula (2F-Eu)
(EA)3-x(Ln)2(BN2)2:Smx formula (2F-Sm-a)
(EA)3(Ln)2-y(BN2)2:Cey formula (2F-Ce)
(EA)3(Ln)2-y(BN2)2:Smy formula (2F-Sm-b)
(EA)3(Ln)2-y(BN2)2:Pry formula (2F-Pr)
(EA)3-x(Ln)(BN2)3:Eux formula (2G-Eu)
(EA)3-x(Ln)(BN2)3:Smx formula (2G-Sm-a)
(EA)3(Ln)1-y(BN2)3:Cey formula (2G-Ce)
(EA)3(Ln)1-y(BN2)3:Smy formula (2G-Sm-b)
(EA)3(Ln)1-y(BN2)3:Pry formula (2G-Pr)
(Ln)3-y(BN2)O3:Cey formula (2H-Ce)
(Ln)3-y(BN2)O3:Smy formula (2H-Sm)
(Ln)3-y(BN2)O3:Pry formula (2H-Pr)
A(EA)4(BN2)3:Eux formula (2I-Eu)
A(EA)4-x(BN2)3:Smx formula (2I-Sm)
(EA)4-x(BN2)2O:Eux formula (2J-Eu)
(EA)4-x(BN2)2O:Smx formula (2J-Sm)
(EA)6-x,BN5:Eux formula (2K-Eu)
(EA)6-x,BN5:Smx formula (2K-Sm)
A(EA)4-x(BN2)3:Eux formula (2L-Eu)
A(EA)4-x(BN2)3:Smx formula (2L-Sm)
(EA)2-x(BN2)(Hal):Eux formula (2M-Eu)
(EA)2-x(BN2)(Hal):Smx formula (2M-Sm)
(Ln)6-y(BN3)O6:Cey formula (2N-Ce)
(Ln)6-y(BN3)O6:Smy formula (2N-Sm)
(Ln)6-y(BN3)O6:Pry formula (2N-Pr)
(Ln)5-y(B4N9):Cey formula (2O-Ce)
(Ln)5-y(B4N9):Smy formula (2O-Sm)
(Ln)5-y(B4N9):Pry formula (2O-Pr)
(Ln)6-y(B4N10):Cey formula (2P-Ce)
(Ln)6-y(B4N10):Smy formula (2P-Sm)
(Ln)6-y(B4N10):Pry formula (2P-Pr)
(Ln)4-y(B2N5):Cey formula (2Q-Ce)
(Ln)4-y(B2N5):Smy formula (2Q-Sm)
(Ln)4-y(B2N5):Pry formula (2Q-Pr)
(Ln)5-y(B2N6):Cey formula (2R-Ce)
(Ln)5-y(B2N6):Smy formula (2R-Sm)
(Ln)5-y(B2N6):Pry formula (2R-Pr),
where the symbols and indices used have the meanings given above.
In a preferred embodiment of the compounds of the formula (2B) or the preferred embodiments, f=0. In a further preferred embodiment of the compounds of the formula (2B) or the preferred embodiments, f=1.
If the compounds according to the invention contain alkali metals A, A is preferably selected, identically or differently, from Li and Na, particularly preferably Li.
If the compounds according to the invention contain alkaline-earth metals EA, EA is preferably selected, identically or differently, from Ca, Sr and Ba, particularly preferably Sr and Ba. The compound of the formula (2A) is preferably Sr0.5Ba4(BN2)3 with Eu, Ce, Sm or Pr doping.
If the compounds according to the invention contain rare-earth metals Ln, Ln is preferably selected, identically or differently, from Y, Lu and Gd.
If the compounds according to the invention contain halogens Hal, Hal is preferably selected, identically or differently, from F and Cl, particularly preferably F.
The compounds according to the invention can be in the form of a pure phase or in the form of a mixed phase with other phases. A foreign phase which may arise during the synthesis and does not have an adverse effect on the properties of the compounds according to the invention comprises alkaline-earth metal oxides.
The compounds according to the invention can be prepared by mixing suitable starting materials and calcination, in particular under non-oxidising conditions, preferably under reducing conditions.
The present invention therefore furthermore relates to a process for the preparation of a compound according to the invention, characterised by the following process steps:
The europium source employed in step (a) can be any conceivable europium compound with which a europium-doped boronitride can be prepared. The europium source employed is preferably europium oxide (especially Eu2O3) and/or europium nitride (EuN), in particular EuN.
The cerium source employed in step (a) can be any conceivable cerium compound with which a cerium-doped boronitride can be prepared. The cerium source employed is preferably cerium oxide (especially CeO2) and/or cerium nitride (CeN), in particular CeN.
Suitable starting materials for the elements A, EA, Ln, Sm and/or Pr are the corresponding nitrides, hydrides or also the free metals. If the compounds according to the invention contain Hal, the corresponding halides can also be employed. For the preparation of the oxyboronitrides, the oxides, borates and carbonates can also be employed.
The compounds are preferably employed in a ratio to one another such that the number of atoms of the elements A, EA and/or Ln, of europium, cerium, samarium and/or praseodymium, of boron, of nitrogen and of oxygen essentially corresponds to the desired ratio in the product in the said formulae. In particular, a stoichiometric ratio is used here.
The starting compounds in step (a) are preferably employed in powder form and are processed with one another, for example by means of a mortar, to give a homogeneous mixture. Since the nitrides used are moisture-sensitive, the preparation of the mixtures is preferably carried out in an inert atmosphere, for example under protective gas in a glove box.
The calcination in step (b) is carried out under non-oxidising conditions. Non-oxidising conditions are taken to mean any conceivable non-oxidising atmospheres, in particular substantially oxygen-free atmospheres, i.e. an atmosphere whose maximum oxygen content is <100 ppm, in particular <10 ppm, where vacuum is not suitable as non-oxidising atmosphere in the present case. A non-oxidising atmosphere can be generated, for example, through the use of protective gas, in particular nitrogen or argon. A preferred non-oxidising atmosphere is a reducing atmosphere. The reducing atmosphere is defined as comprising at least one gas with a reducing action. What gases have a reducing action is known to the person skilled in the art. Examples of suitable reducing gases are hydrogen, carbon monoxide, ammonia and ethylene, more preferably hydrogen, where these gases may also be mixed with other non-oxidising gases. The reducing atmosphere is particularly preferably generated by a mixture of nitrogen and hydrogen, preferably in the H2:N2 ratio of 1:99 to 20:80, preferably 3:97 to 10:90, in each case based on the volume.
The calcination is preferably carried out at a temperature in the range from 900° C. to 2000° C., particularly preferably 1000° C. to 1700° C., very particularly preferably from 1000° C. to 1400° C.
The calcination duration here is preferably 1 to 14 h, particularly preferably 2 to 12 h and in particular 5 to 10 h.
The calcination is preferably carried out by introducing the mixtures obtained, for example, into a high-temperature oven in a boron nitride vessel. The high-temperature oven is, for example, a tubular furnace which contains a molybdenum foil tray.
After preparation, the phosphors obtained in this way are usually deagglomerated and sieved.
In a further embodiment, the compounds according to the invention may be coated. Suitable for this purpose are all coating methods as are known to the person skilled in the art in accordance with the prior art and are used for phosphors. Suitable materials for the coating are, in particular, metal oxides and nitrides, in particular alkaline-earth metal oxides, such as Al2O3, and alkaline-earth metal nitrides, such as AlN, as well as SiO2. The coating here can be carried out, for example, by fluidised-bed methods. Further suitable coating methods are known from JP 04-304290, WO 91/10715, WO 99/27033, US 2007/0298250, WO 2009/065480 and WO 2010/075908. It is also possible to apply an organic coating as an alternative and/or in addition to the above-mentioned inorganic coating.
The present invention furthermore relates to the use of the compound according to the invention as phosphor, in particular as conversion phosphor.
The term “conversion phosphor” in the sense of the present application is taken to mean a material which absorbs radiation in a certain wavelength region of the electromagnetic spectrum, preferably in the blue or UV spectral region, and emits visible light in another wavelength region of the electromagnetic spectrum, preferably in the red or orange spectral region, in particular in the red spectral region. The term “radiation-induced emission efficiency” should also be understood in this connection, i.e. the conversion phosphor absorbs radiation in a certain wavelength region and emits radiation with a certain efficiency in another wavelength region. The term “shift of the emission wavelength” is taken to mean that a conversion phosphor emits light at a different wavelength, i.e. shifted to a shorter or longer wavelength, compared with another or similar conversion phosphor. The emission maximum is thus shifted.
The present invention furthermore relates to an emission-converting material comprising a compound of one of the above-mentioned formulae according to the invention. The emission-converting material may consist of the compound according to the invention and would in this case be equivalent to the term “conversion phosphor” defined above.
It is also possible for the emission-converting material according to the invention to comprise further conversion phosphors besides the compound according to the invention. In this case, the emission-converting material according to the invention comprises a mixture of at least two conversion phosphors, where one of these is a compound according to the invention. It is particularly preferred for the at least two conversion phosphors to be phosphors which emit light of different wavelengths which are complementary to one another. If the compound according to the invention is a red-emitting phosphor, this is preferably employed in combination with a green- or yellow-emitting phosphor or also with a cyan- or blue-emitting phosphor. Alternatively, the red-emitting conversion phosphor according to the invention can also be employed in combination with (a) blue- and green-emitting conversion phosphor(s). Alternatively, the red-emitting conversion phosphor according to the invention can also be employed in combination with (a) green-emitting conversion phosphor(s). It may thus be preferred for the conversion phosphor according to the invention to be employed in the emission-converting material according to the invention in combination with one or more further conversion phosphors, which then together preferably emit white light.
In the context of this application, blue light denotes light whose emission maximum lies between 400 and 459 nm, cyan light denotes light whose emission maximum lies between 460 and 505 nm, green light denotes light whose emission maximum lies between 506 and 545 nm, yellow light denotes light whose emission maximum lies between 546 and 565 nm, orange light denotes light whose emission maximum lies between 566 and 600 nm and red light denotes light whose emission maximum lies between 601 and 670 nm. The compound according to the invention is preferably a red-emitting conversion phosphor.
In general, any possible conversion phosphor can be employed as a further conversion phosphor which can be employed together with the compound according to the invention. The following, for example, are suitable here: Ba2SiO4:Eu2+, BaSi2O6:Pb2+, BaxSr1-xF2:Eu2+, BaSrMgSi2O7:Eu2+, BaTiP2O7, (Ba, Ti)2P2O7:Ti, Ba3WO6:U, BaY2F8:Er3+,Yb+, Be2SiO4:Mn2+, Bi4Ge3O12, CaAl2O4:Ce3+, CaLa4O7:Ce3+, CaAl2O4:El2+, CaAl2O4:Mn2+, CaAl4O7:Pb2+, Mn2+, CaAl2O4:Tb3+, Ca3Al2Si3O12:Ce3+, Ca3Al2Si3Oi2:Ce3+, Ca3Al2Si3O2:El2+, Ca2B5O9Br:Eu2+, Ca2B5O9Cl:Eu2+, Ca2B5O9Cl:Pb2+, CaB2O4:Mn2+, Ca2B2O5:Mn2+, CaB2O4:Pb2+, CaB2P2O9:El2+, Ca5B2SiO10:Eu3+, Ca0.5Ba0.5Al12O19:Ce3+,Mn2+, Ca2Ba3(PO4)3Cl:Eu2+, CaBr2:Eu2+ in SiO2, CaCl2:Eu2+ in SiO2, CaCl2:Eu2+,Mn2+ in SiO2, CaF2:Ce3+, CaF2:Ce3+,Mn2+, CaF2:Ce3+,Tb3+, CaF2:Eu2+, CaF2:Mn2+, CaF2:U, CaGa2O4:Mn2+, CaGa4O7:Mn2+, CaGa2S4:Ce3+, CaGa2S4:Eu2+, CaGa2S4:Mn2+, CaGa2S4:Pb2+, CaGeO3:Mn2+, CaI2:Eu2+ in SiO2, CaI2:Eu2+,Mn2+ in SiO2, CaLaBO4:Eu3+, CaLaB3O7:Ce3+,Mn2+, Ca2La2BO6.6:Pb2+, Ca2MgSi2O7, Ca2MgSi2O7:Ce3+, CaMgSi2O6:Eu2+, Ca3MgSi2O8:Eu2+, Ca2MgSi2O7:Eu2+, CaMgSi2O6:Eu2+,Mn2+, Ca2MgSi2O7:Eu2+,Mn2+, CaMoO4, CaMoO4:Eu3+, CaO:Bi3+, CaO:Cd2+, CaO:Cut, CaO:Eu3+, CaO:Eu3+, Nat, CaO:Mn2+, CaO:Pb2+, CaO:Sb3+, CaO:Sm3+, CaO:Tb3+, CaO:Tl, CaO:Zn2+, Ca2P2O7:Ce3+, α-Ca3(PO4)2:Ce3+, β-ca3(PO4)2:ce3+, Ca6(PO4)3Cl:Eu2+, Ca6(PO4)3Cl:Mn2+, Ca6(PO4)3Cl:Sb3+, Ca6(PO4)3Cl:Sn2+, β-Ca3(PO4)2:Eu2+,Mn2+, Ca6(PO4)3F:Mn2+, Ca5(PO4)3F:Sb3+, Ca5(PO4)3F:Sn2+, α-Ca3(PO4)2:Eu2+, β-Ca3(PO4)2:Eu2+, Ca2P2O7:Eu2+, Ca2P2O7:Eu2+,Mn2+, CaP2O6:Mn2+, α-Ca3(PO4)2:Pb2+, α-Ca3(PO4)2:Sn2+, β-Ca3(PO4)2:Sn2+, β-Ca2P2O7:Sn,Mn, α-Ca3(PO4)2:Tr, CaS:Bi3+, CaS:Bi3+,Na, CaS:Ce3+, CaS:Eu2+, CaS:Cut,Nat, CaS:La3+, CaS:Mn2+, CaSO4:Bi, CaSO4:Ce3+, CaSO4:Ce3+,Mn2+, CaSO4:Eu2+, CaSO4:Eu2+,Mn2+, CaSO4:Pb2+, CaS:Pb2+, CaS:Pb2+,Cl, CaS:Pb2+,Mn2+, CaS:Pr3+,Pb2+,Cl, CaS:Sb3+, CaS:Sb3+,Na, CaS:Sm3+, CaS:Sn2+, CaS:Sn2+,F, CaS:Tb3+, CaS:Tb3+,Cl, CaS:Y3+, CaS:Yb2+, CaS:Yb2+,Cl, CaSiO3:Ce3+, Ca3SiO4Cl2:El2+, Ca3SiO4Cl2:Pb2+, CaSiO3:El2+, CaSiO3:Mn2+,Pb, CaSiO3:Pb2+, CaSiO3:Pb2+,Mn2+, CaSiO3:Ti4+, CaSr2(PO4)2:Bi3+, β-(Ca,Sr)3(PO4)2:Sn2+Mn2+, CaTi0.9Al0.1O3:Bi3+, CaTiO3:Eu3+, CaTiO3:Pr3+, Ca6(VO4)3Cl, CaWO4, CaWO4:Pb2+, CaWO4:W, Ca3WO6:U, CaYAlO4:Eu3+, CaYBO4:Bi3+, CaYBO4:Eu3+, CaYB0.8O3.7:Eu3+, CaY2ZrO6:Eu3+, (Ca,Zn,Mg)3(PO4)2:Sn, CeF3, (Ce,Mg)BaAl11O18:Ce, (Ce,Mg)SrAl11O18:Ce, CeMgAl11O19:Ce:Tb, Cd2B6O11:Mn2+, CdS:Ag+,Cr, CdS:In, CdS:In, CdS:In,Te, CdS:Te, CdWO4, CsF, CsI, CsI:Na+, CsI:Tl, (ErCl3)0.26(BaCl2)0.75, GaN:Zn, Gd3Ga6O12:Cr3+, Gd3Ga5O12:Cr,Ce, GdNbO4:Bi3+, Gd2O2S:Eu3+, Gd2O2Pr3+, Gd2O2S:Pr,Ce,F, Gd2O2S:Tb3+, Gd2SiO6:Ce3+, KAl11O17:Tl+, KGa11O17:Mn2+, K2La2Ti3O10:Eu, KMgF3:Eu2+, KMgF3:Mn2+, K2SiF6:Mn4+, LaAl3B4O12:Eu3+, LaAlB2O6:Eu3+, LaAlO3:Eu3+, LaAlO3:Sm3+, LaAsO4:Eu3+, LaBr3:Ce3+, LaBO3:Eu3+, (La,Ce,Tb)PO4:Ce:Tb, LaCl3:Ce3+, La2O3:Bi3+, LaOBr:Tb3+, LaOBr:Tm3+, LaOCl:Bi3+, LaOCl:Eu3+, LaOF:Eu3+, La2O3:Eu3+, La2O3:Pr3+, La2O2S:Tb3+, LaPO4:Ce3+, LaPO4:Eu3+, LaSiO3Cl:Ce3+, LaSiO3Cl:Ce3+,Tb3+, LaVO4:Eu3+, La2W3O12:Eu3+, LiAlF4:Mn2+, LiAl5O8:Fe3+, LiAlO2:Fe3+, LiAlO2:Mn2+, LiAl5O8:Mn2+, Li2CaP2O7:Ce3+,Mn2+, LiCeBa4Si4O14:Mn2+, LiCeSrBa3Si4O14:Mn2+, LiInO2:Eu3+, LiInO2:Sm3+, LiLaO2:Eu3+, LuAlO3:Ce3+, (Lu,Gd)2SiO5:Ce3+, Lu2SiO5:Ce3+, Lu2Si2O7:Ce3+, LuTaO4:Nb5+, Lu1-xYxAlO3:Ce3+, MgAl2O4:Mn2+, MgSrAl10O17:Ce, MgB2O4:Mn2+, MgBa2(PO4)2:Sn2+, MgBa2(PO4)2:U, MgBaP2O7:Eu2+, MgBaP2O7:Eu2+,Mn2+, MgBa3Si2O8:Eu2+, MgBa(SO4)2:Eu2+, Mg3Ca3(PO4)4:Eu2+, MgCaP2O7:Mn2+, Mg2Ca(SO4)3:Eu2+, Mg2Ca(SO4)3:Eu2+,Mn2, MgCeAlnO19:Tb3+, Mg4(F)GeO6:Mn2+, Mg4(F)(Ge,Sn)O6:Mn2+, MgF2:Mn2+, MgGa2O4:Mn2+, Mg8Ge2Oii F2:Mn4+, MgS:Eu2+, MgSiO3:Mn2+, Mg2SiO4:Mn2+, Mg3SiO3F4:Ti4+, MgSO4:Eu2+, MgSO4:Pb2+, MgSrBa2Si2O7:Eu2+, MgSrP2O7:Eu2+, MgSr5(PO4)4:Sn2+, MgSr3Si2O8:Eu2+,Mn2+, Mg2Sr(SO4)3:Eu2+, Mg2TiO4:Mn4+, MgWO4, MgYBO4:Eu3+, Na3Ce(PO4)2:Tb3+, NaI:Tl, Na1.23K0.42Eu0.12TiSi4O11:Eu3+, Na1.23K0.42Eu0.12TiSi5O13.xH2O:Eu3+, Na1.29K0.46Er0.08TiSi4O11:Eu3+, Na2Mg3Al2Si2O10:Tb, Na(Mg2Mnx)LiSi4O10F2:Mn, NaYF4:Er3+, Yb3+, NaYO2:Eu3+, P46(70%)+P47 (30%), SrAl12O19:Ce3+, Mn2+, SrAl2O4:Eu2+, SrAl4O7:Eu3+, SrAl12O19:Eu2+, SrAl2S4:Eu2+, Sr2B5O9Cl:Eu2+, SrB4O7:Eu2+(F,Cl,Br), SrB4O7:Pb2+, SrB4O7:Pb2+, Mn2+, SrB8O13:Sm2+, SrxBayClzAl2O4-z/2: Mn2+, Ce3+, SrBaSiO4:Eu2+, Sr(Cl,Br,I)2:Eu2+ in SiO2, SrCl2:Eu2+ in SiO2, Sr5Cl(PO4)3:Eu, SrwFxB4O6.5:Eu2+, SrwFxByOz:Eu2+,Sm2+, SrF2:Eu2+, SrGa12O19:Mn2+, SrGa2S4:Ce3+, SrGa2S4:Eu2+, SrGa2S4:Pb2+, SrIn2O4:Pr3+, Al3+, (Sr,Mg)3(PO4)2:Sn, SrMgSi2O6:Eu2+, Sr2MgSi2O7:Eu2+, Sr3MgSi2O8:Eu2+, SrMoO4:U, SrO.3B2O3:Eu2+,Cl, β-srO.3B2O3:Pb2+, β-SrO.3B2O3:Pb2+,Mn2+, α-SrO.3B2O3:Sm2+, Sr6P5BO20:Eu, Sr5(PO4)3Cl:Eu2+, Sr5(PO4)3Cl:Eu2+,Pr3+, Sr5(PO4)3Cl:Mn2+, Sr5(PO4)3Cl:Sb3+, Sr2P2O7:Eu2+, β-Sr3(PO4)2:Eu2+, Sr5(PO4)3F:Mn2+, Sr5(PO4)3F:Sb3+, Sr5(PO4)3F:Sb3+,Mn2+, Sr5(PO4)3F:Sn2+, Sr2P2O7:Sn2+, β-Sr3(PO4)2:Sn2+, β-Sr3(PO4)2:Sn2+,Mn2+(Al), SrS:Ce3+, SrS:Eu2+, SrS:Mn2+, SrS:Cu+,Na, SrSO4:Bi, SrSO4:Ce3+, SrSO4:Eu2+, SrSO4:Eu2+,Mn2+, Sr5Si4O10Cl6:Eu2+, Sr2SiO4:Eu2+, SrTiO3:Pr3+, SrTiO3:Pr3+,Al3+, Sr3WO6:U, SrY2O3:Eu3+, ThO2:Eu3+, ThO2:Pr3+, ThO2:Tb3+, YAl3B4O12:Bi3+, YAl3B4O12:Ce3+, YAl3B4O12:Ce3+,Mn, YAl3B4O12:Ce3+,Tb3+, YAl3B4O12:Eu3+, YAl3B4O12:Eu3+,Cr3+, YAl3B4O12:Th4+,Ce3+,Mn2+, YAlO3:Ce3+, Y3Al5O12:Ce3+, Y3Al5O12:Cr3+, YAlO3:Eu3+, Y3Al5O12:Eu3r, Y4Al2O9:Eu3+, Y3Al5O12:Mn4+, YAlO3:Sm3+, YAlO3:Tb3+, Y3Al5O12:Tb3+, YAsO4:Eu3+, YBO3:Ce3+, YBO3:Eu3+, YF3:Er3+,Yb3+, YF3:Mn2+, YF3:Mn2+,Th4+, YF3:Tm3+,Yb3+, (Y,Gd)BO3:Eu, (Y,Gd)BO3:Tb, (Y,Gd)2O3:Eu3+, Y1.34Gd0.60O3(Eu,Pr), Y2O3:Bi3+, YOBrEu3+, Y2O3:Ce, Y2O3:Er3+, Y2O3:Eu3+(YOE), Y2O3:Ce3+,Tb3+, YOCl:Ce3+, YOCl:Eu3+, YOF:Eu3+, YOF:Tb3+, Y2O3:Ho3+, Y2O2S:Eu3+, Y2O2S:Pr3+, Y2O2S:Tb3+, Y2O3:Tb3+, YPO4:Ce3+, YPO4:Ce3+,Tb3+, YPO4:Eu3+, YPO4:Mn2+,Th4+, YPO4:V5+, Y(P,V)O4:Eu, Y2SiO5:Ce3+, YTaO4, YTaO4:Nb5+, YVO4:Dy3+, YVO4:Eu3+, ZnAl2O4:Mn2+, ZnB2O4:Mn2+, ZnBa2S3:Mn2+, (Zn,Be)2SiO4:Mn2+, Zn0.4Cd0.6S:Ag, Zn0.6CdoAS:Ag, (Zn,Cd)S:Ag,Cl, (Zn,Cd)S:Cu, ZnF2:Mn2+, ZnGa2O4, ZnGa2O4:Mn2+, ZnGa2S4:Mn2+, Zn2GeO4:Mn2+, (Zn,Mg)F2:Mn2+, ZnMg2(PO4)2:Mn2+, (Zn,Mg)3(PO4)2:Mn2+, ZnO:Al3+,Ga3+, ZnO:Bi3+, ZnO:Ga3+, ZnO:Ga, ZnO—CdO:Ga, ZnO:S, ZnO:Se, ZnO:Zn, ZnS:Ag+,Cl−, ZnS:Ag,Cu,Cl, ZnS:Ag,Ni, ZnS:Au,In, ZnS—CdS (25-75), ZnS—CdS (50-50), ZnS—CdS (75-25), ZnS—CdS:Ag,Br,Ni, ZnS—CdS:Ag+,Cl, ZnS—CdS:Cu,Br, ZnS—CdS:Cu,I, ZnS:Cl−, ZnS:Eu2+, ZnS:Cu, ZnS:Cu+,Al3+, ZnS:Cu+,Cl−, ZnS:Cu,Sn, ZnS:Eu2+, ZnS:Mn2+, ZnS:Mn,Cu, ZnS:Mn2+,Te2+, ZnS:P, ZnS:Pb2+, ZnS:Pb2+,Cl−, ZnS:Pb,Cu, Zn3(PO4)2:Mn2+, Zn2SiO4:Mn2+, Zn2SiO4:Mn2+,As5+, Zn2SiO4:Mn,Sb2O2, Zn2SiO4:Mn2+,P, Zn2SiO4:Ti4+, ZnS:Sn2+, ZnS:Sn,Ag, ZnS:Sn2+,Li+, ZnS:Te,Mn, ZnS—ZnTe:Mn2+, ZnSe:Cu+,Cl or ZnWO4.
The present invention furthermore relates to the use of the emission-converting material according to the invention in a light source. The light source is particularly preferably an LED, in particular a phosphor-converted LED, pc-LED for short. It is particularly preferred here for the emission-converting material to comprise at least one further conversion phosphor besides the conversion phosphor according to the invention, in particular so that the light source emits white light or light having a certain colour point (colour-on-demand principle). The “colour-on-demand principle” is taken to mean the achievement of light having a certain colour point with a pc-LED using one or more conversion phosphors.
The present invention thus furthermore relates to a light source which comprises a primary light source and the emission-converting material.
Here too, it is particularly preferred for the emission-converting material to comprise at least one further conversion phosphor besides the conversion phosphor according to the invention, so that the light source preferably emits white light or light having a certain colour point.
The light source according to the invention is preferably a pc-LED. A pc-LED generally comprises a primary light source and an emission-converting material. The emission-converting material according to the invention can for this purpose either be dispersed in a resin (for example epoxy or silicone resin) or, given suitable size ratios, arranged directly on the primary light source or alternatively, depending on the application, remote therefrom (the latter arrangement also includes “remote phosphor technology”).
The primary light source can be a semiconductor chip, a luminescent light source, such as ZnO, a so-called TCO (transparent conducting oxide), a ZnSe- or SiC-based arrangement, an arrangement based on an organic light-emitting layer (OLED) or a plasma or discharge source, most preferably a semiconductor chip. If the primary light source is a semiconductor chip, it is preferably a luminescent indium aluminium gallium nitride (InAlGaN), as is known from the prior art. Possible forms of primary light sources of this type are known to the person skilled in the art. Furthermore, lasers are suitable as light source.
For use in light sources, in particular pc-LEDs, the emission-converting material according to the invention can also be converted into any desired outer shapes, such as spherical particles, flakes and structured materials and ceramics. These shapes are summarised under the term “shaped bodies”. The shaped bodies are consequently emission-converting shaped bodies.
The invention furthermore relates to a lighting unit which comprises at least one light source according to the invention. Lighting units of this type are employed principally in display devices, in particular liquid-crystal display devices (LC displays) with backlighting. The present invention therefore also relates to a display device of this type.
In the lighting unit according to the invention, the optical coupling between the emission-converting material and the primary light source (in particular semiconductor chips) preferably takes place by means of a light-conducting arrangement. In this way, it is possible for the primary light source to be installed at a central location and for this to be optically coupled to the emission-converting material by means of light-conducting devices, such as, for example, optical fibres. In this way, it is possible to achieve lamps adapted to the lighting wishes which consist of one or more different conversion phosphors, which may be arranged to form a light screen, and an optical waveguide, which is coupled to the primary light source. In this way, it is possible to place a strong primary light source at a location which is favourable for electrical installation and to install lamps comprising emission-converting materials, which are coupled to the optical waveguides, without further electrical cabling, merely by laying optical waveguides at any desired locations.
The following examples and figures are intended to illustrate the present invention. However, they should in no way be regarded as limiting.
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.
2.3982 g (23.76 mmol) of Mg3N2, 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 N2/H2 (95%/5%).
2.2175 g (14.96 mmol) of Ca3N2, 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 N2/H2 (95%/5%).
2.5228 g (8.67 mmol) of Sr3N2, 0.4348 g (17.52 mmol) of BN and 0.0405 g (0.26 mmol) of EuH2 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 N2/H2. All manipulations of the starting materials are carried out in an N2-filled glove box.
0.2028 g (0.70 mmol) of Sr3N2, 2.4794 g (5.63 mmol) of Ba3N2, 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 N2/H2. All manipulations of the starting materials are carried out in an N2-filled glove box.
0.2028 g (0.70 mmol) of Sr3N2, 2.4793 g (5.63 mmol) of Ba3N2, 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 N2/H2. All manipulations of the starting materials are carried out in an N2-filled glove box.
1.2288 g (4.22 mmol) of Sr3N2, 0.2118 g (8.53 mmol) of BN, 0.0283 g (0.17 mmol) of EuN and 0.5360 g (4.27 mmol) of SrF2 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 N2/H2. All manipulations of the starting materials are carried out in an N2-filled glove box.
General Procedure for the Construction and Measurement of pcLEDs
A mass mp (in g) of the phosphor shown in the respective LED example is weighed out, mixed with msilicone (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 cp (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
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.
| Number | Date | Country | Kind |
|---|---|---|---|
| 14003462.0 | Oct 2014 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2015/001879 | 9/22/2015 | WO | 00 |
