Fluorescent substance, method for providing the same and white light-emitting diode

Abstract

A method of producing a nitride-based phosphor, the method comprising: a first sintering process to divide a plurality of starting materials into at least two groups and to sinter the respective groups; and a second sintering process to mix and sinter products produced after sintering the respective groups, whereby at least one of the plurality of starting materials is contained in each of the at least two groups, and the starting materials Eu, Si, O and M, which is at least one of Ca, Sr and Ba.

Description

Technical area

[0001] The present invention relates to a phosphor which has excellent high-temperature stability and high emission characteristics when used in a light-emitting diode (LED). State of the art

[0002] A white light-emitting diode (LED) features low power consumption and a long lifespan, while it does not contain toxic heavy metals such as mercury. Therefore, the white LED is being spotlighted as a next-generation artificial light source, effective for energy saving and environmental protection. Due to such characteristics, the white LED is rapidly being put into practical use as a backlight unit (BLU) for liquid crystal displays (LCDs) for TVs, a low beam for vehicles, and other general lighting applications. Demand for the white LED will rapidly increase.

[0003] Nowadays, white LEDs are mainly manufactured by using a yellow phosphor on a blue LED chip. That is, the above process achieves white light by combining blue light emitted by a blue LED and yellow light emitted by a phosphor excited by a portion of the blue light. A representative of the phosphor that emits yellow light is YAG:Ce. 3+ ((Y,Gd)3(Al,Ga)5O 12 :Ce 3+ ) from Nichia Chemical (Japan), which is known for its high emission efficiency and chemical stability.

[0004] Recently, research is underway to find a replacement for Nichia Chemical's yellow phosphor. A phosphor that uses an oxynitride as the parent material, such as MSi2O2N2:Eu 2+can be an example of replacement. The oxynitride-based phosphor is chemically stable and is capable of shifting a light emission wavelength by varying an M ion type and Eu ion concentration. Consequently, the oxynitride-based phosphor is attracting attention as a phosphor for white LEDs. In addition, the oxynitride-based phosphor has a crystalline structure with M ions and Eu ions arranged two-dimensionally (2D) within a 2D layered structure constituted by SiON3 tetrahedra. Therefore, the oxynitride-based phosphor is expected to exhibit considerably less emission reduction due to concentration quenching compared with a phosphor having a 3D arrangement of Eu ions.

[0005] Generally, oxynitride-based phosphors are synthesized by a solid-phase method, which uses a solid powder as a raw material. The solid-phase method can produce a nearly single-phase material only when no Eu or a low concentration of Eu is added. When high concentrations of Eu are added, i.e., when Eu raw materials (generally Eu2O3) are increased, the oxygen content may become excessive, easily producing impurities. As a result, oxynitride-based phosphors can hardly be synthesized in a single phase.

[0006] The publication by Bachmann et al. (Chem. Mater., Vol. 21, 2009, No. 2, pages 316 to 325) and the published patent application EP 2 246 909 A1 disclose prior art white light-emitting diodes. Disclosure of the inventionTechnical objectives

[0007] One aspect of the present invention provides an improved yellow phosphor capable of replacing a conventional yttrium aluminum garnet (YAG) phosphor by having excellent high-temperature stability and high emission characteristics, and a method for producing the same. Technical solutions

[0008] The above and / or other aspects are achieved by providing a method for producing a nitride-based phosphor, the method comprising a first sintering process for separating a plurality of precursors into at least two groups and sintering the respective groups; and a second sintering process for mixing and sintering products produced after sintering the respective groups. At least one of the plurality of precursors is included in each of the at least two groups, and the precursors include Eu, Si, O, and M, which is at least one of Ca, Sr, and Ba.

[0009] A sintering temperature in the second sintering process may be higher than a sintering temperature in the first sintering process.

[0010] The second sintering process can be carried out under a nitrogen and a hydrogen gas atmosphere.

[0011] The above and / or other aspects are achieved by providing a method for producing a phosphor expressed by the following composition formula: M 1-z Eu z Si a O3N c (M=Sr 1-x-y Ba x Ca y, 0≤x≤0,5; 0≤y≤0,2; 0<z≤0,3; 2≤a≤2,5; 1,5≤ b≤ 2; und 2≤c≤2,5), wobei das Verfahren einen ersten Sintervorgang, welcher ein Sintern einer ersten Mischung aufweist, um ein erstes gesintertes Produkt durch ein Mischen und ein Sintern einer ersten Ausgangsstoffgruppe zu erzeugen, welche einen M-Ausgangsstoff und einen ersten Si-Ausgangsstoff aufweist, und ein Sintern einer zweiten Mischung aufweist, um ein zweites gesintertes Produkt durch ein Mischen und Sintern einer zweiten Ausgangsstoffgruppe zu erzeugen, welche einen Eu-Ausgangsstoff und einen zweiten Si-Ausgangsstoff aufweist; und einen zweiten Sintervorgang aufweist, um das erste gesinterte Produkt und das zweite gesinterte Produkt zu mischen und zu sintern.

[0012] The first sintering process may include sintering the first mixture to produce the first sintered product by mixing and sintering the first raw material group containing MCO3 and SiO2; and sintering the second mixture to produce the second sintered product by mixing and sintering the second group containing Eu2O3, SiO2 and Si3N4.

[0013] Sintering of the first mixture can be carried out at a temperature of approximately 900°C to approximately 1300°C.

[0014] The sintering of the second mixture can be carried out at a temperature of about 1200°C to about 1400°C.

[0015] A silicon nitride compound can be added during sintering of the second mixture.

[0016] Si3N4 can be added during sintering of the second mixture.

[0017] The sintering of the second mixture may add at least one of NH4A, where A denotes at least one of F and Cl, KB2, where K denotes at least one of Ca, Sr and Ba and B denotes at least one of F and Cl, and LB, where L denotes at least one of Na and K and B denotes at least one of F and Cl.

[0018] The sintering of the second mixture can be carried out under a nitrogen and hydrogen gas atmosphere.

[0019] The sintering of the second mixture can be carried out at a temperature of about 1300°C to about 1600°C.

[0020] The first sintered product may comprise a solid solution containing at least two kinds of M ions.

[0021] The second sintered product may comprise EuSi2O2N2.

[0022] The foregoing and / or other aspects are also achieved by providing a correspondingly prepared phosphor in a single phase, which is expressed by the following composition formula: M 1-z Eu z Si a O b N c (M = Sr 1x-y Ba x Ca y , 0 <x<0,5, 0<y≤0,2; 0<z≤0,3; 2<a<2,5; 1,5 ≤ b ≤ 2; und 2 ≤ c ≤ 2,5), wobei die Konzentration eines Oxynitrids, welches ein Atomverhältnis von O / N > 1 is 1 mol / % or less with respect to the total phosphor.

[0023] When a light-emitting diode (LED) is operated, the phosphor may have at least 80% emission intensity of an emission intensity under normal temperature at a temperature of about 150°C to about 200°C.

[0024] The foregoing and / or other aspects are also achieved by providing a white LED comprising a single phase phosphor represented by the composition formula M 1-z Eu z Si a O b N c (M = Sr 1-x-y Ba x Ca y , 0 ≤ x ≤ 0.5; 0 ≤ y ≤ 0.2; 0 < z ≤ 0.3; 2 ≤ a ≤ 2.5; 1.5 ≤ b ≤ 2; and 2 ≤ c ≤ 2.5), as a yellow phosphor which is a wavelength converting material, wherein the concentration of an oxynitride having an atomic ratio of O / N > 1 is 1 mol / % or less with respect to the entire phosphor.

[0025] The white LED may have at least 80% emission intensity of a normal temperature emission intensity at a temperature of about 150° to about 200°C.

[0026] The foregoing and / or other aspects are also achieved by providing a correspondingly prepared nitride-based phosphor as a phosphor expressed by the following composition formula: M 1-n Eu n Si a O b N c (M = Sr 1-m Ba m , 0.25 <m<0,3; 0<m×(1-n) < 0,25; 2 ≤ a<2,5; 1,5 ≤ b ≤ 2; und 2 ≤ c ≤ 2,5), wobei die Konzentration eines Oxynitrids, welches ein Atomverhältnis von O / N > 1 is 0.01 mol / % or less with respect to the total phosphor.

[0027] The phosphor can have a triclinic crystal system and a space group P1.

[0028] The phosphor can form a complete solid solution in a Sr-Eu system or in a Sr-Ba-Eu system.

[0029] Scattering angles with respect to three diffraction peaks having high intensity can be respectively in a range of 12.50 ≤ 2Θ ≤ 12.60; 25.16 ≤ 2Θ ≤ 25.30 and 31.51 ≤ 2Θ ≤ 31.65 in an X-ray diffraction (XRD) pattern of the phosphor.

[0030] The phosphor can have an emission wavelength in a range of 460 nm to 750 nm.

[0031] The foregoing and / or other aspects are also achieved by providing a nitride-based phosphor as a single-phase phosphor, which is expressed by the following composition formula: M 1-n Eu n Si a O b N c (M = Sr 1-m Ba m ; 0.6 < m < 0.8; 0.5 < m×(1-n) < 0.65; 2 ≤ a ≤ 2.5; 1.5 ≤ b ≤ 2; and 2 ≤ c ≤ 2.5), wherein the concentration of an oxynitride having an atomic ratio of O / N > 1 is 0.01 mol / % or less with respect to the entire phosphor.

[0032] The phosphor can have a triclinic crystal system and a space group P1.

[0033] The phosphor can form a completely solid solution in a Sr-Ba-Eu system.

[0034] Diffraction angles with respect to four diffraction peaks having high intensity may be respectively in the range of 12.30 ≤ 2Θ < 12.38; 24.75 ≤ 2Θ < 24.88; 25.56 ≤ 2Θ < 25.62 and 31.09 ≤ 2Θ ≤ 31.25 in an XRD pattern of the phosphor.

[0035] The phosphor can have an emission wavelength in a range of 465 nm to 765 nm.

[0036] The foregoing and / or other aspects are also achieved by providing a correspondingly prepared nitride-based phosphor as a mixed-phase phosphor consisting of an initial composition M 1-n Eu n Si a O b N c (M = Sr 1-m Ba m; 0.3 < m < 0.6; 0.25 < m×(1-n) < 0.5; 2 ≤ a ≤ 2.5; 1.5 ≤ b ≤ 2; and 2 ≤ c ≤ 2.5), wherein the concentration of an oxynitride having an atomic ratio of O / N > 1 is 0.01 mol / % or less with respect to the entire phosphor.

[0037] The phosphor can have two different phases, which have a triclinic crystal system and a space group P1.

[0038] The phosphor can have two different phases, forming a completely solid solution in a Sr-Ba-Eu system.

[0039] In an XRD pattern of the phosphor, one of the two different phases may have diffraction angles with respect to three diffraction peaks having high intensity, the diffraction angles being respectively in a range of 12.47 ≤ 2Θ ≤ 12.49; 25.13 ≤ 2Θ ≤ 25.15 and 31.48 ≤ 2Θ ≤ 31.50, and the other one may have diffraction angles with respect to three diffraction peaks having high intensity, the diffraction angles being respectively in a range of 12.39 ≤ 2Θ < 12.45; 24.89 ≤ 2Θ ≤ 24.95 and 31.26 ≤ 2Θ ≤ 31.41.

[0040] The phosphor can have an emission wavelength in a range of 460 nm to 760 nm. Effects

[0041] A nitride-based phosphor according to the exemplary embodiments can be formed in a single phase even with high Eu concentrations. Also, since the nitride-based phosphor has excellent high-temperature stability and crystallinity, a yellow phosphor with improved emission characteristics can be achieved.

[0042] Additionally, according to a method for producing the nitride-based phosphor according to the exemplary embodiments, a solid solution containing at least two types of M ions can be synthesized. Also, the production of impurities caused by an increase in oxygen in a feed compound can be effectively reduced. Short description of the drawings Fig.1 illustrates a flowchart conceptually showing a method of manufacturing a nitride-based phosphor according to example embodiments; Fig. 2 illustrates a flowchart showing a method for manufacturing a nitride-based phosphor according to a first embodiment; Fig. 3 illustrates a flowchart showing a method for manufacturing a nitride-based phosphor according to a first comparative example; Fig. 4 illustrates a graph showing emission intensity according to temperature with respect to a phosphor prepared in the first embodiment and a phosphor prepared in a second comparative example; Fig.5 illustrates emission spectra of the phosphor of the first embodiment, the phosphor of the first comparative example, and the phosphor of the second comparative example; Fig. 6 illustrates a sectional view showing a structure of a white light-emitting diode (LED) according to exemplary embodiments; Fig. 7A and Fig. 7B illustrate diagrams each showing an X-ray diffraction (XRD) pattern and an emission spectrum of a phosphor prepared in a second embodiment; Fig. 8A and Fig. 8B illustrate diagrams showing an XRD pattern and an emission spectrum of a phosphor prepared in a third embodiment, respectively; Fig. 9A and Fig.9B are diagrams showing an XRD pattern and an emission spectrum of a phosphor prepared in a fourth embodiment; Fig. 10 illustrates a diagram showing a Rietveld fit result with respect to a phosphor manufactured in a fifth embodiment; Fig. 11 illustrates diagrams showing XRD patterns of phosphor host materials prepared in a sixth embodiment to a 26th embodiment; and Fig. 12A and Fig. 12B are diagrams showing XRD patterns and emission spectra of phosphors prepared in a 27th embodiment to a 41st embodiment. Best mode for carrying out the invention

[0043] Reference will now be made in detail to exemplary embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. Exemplary embodiments are described below to explain the present invention by reference to the figures.

[0044] Fig. 1 illustrates a flowchart conceptually illustrating a method of manufacturing a nitride-based phosphor according to example embodiments.

[0045] Referring to Fig.1, a plurality of precursors are first provided to produce the nitride-based phosphor. The plurality of precursors are divided into two groups, i.e., a first group and a second group. The first group includes an M precursor containing at least one of Ca, Sr, and Ba, and a first Si precursor. The second group includes an Eu precursor and a second Si precursor. However, unlike the exemplary embodiments, the plurality of precursors may be divided into three or more groups.

[0046] The M precursor may comprise a metal carbonate (MCO3). The first Si precursor may comprise SiO2. The Eu precursor may be Eu2O3. The second Si precursor may comprise SiO2 and Si3N4. Accordingly, the first Si precursor and the second Si precursor may both comprise the same precursor, i.e., SiO2.

[0047] The raw materials of each group undergo a mixing process. Either a dry mixing process or a wet mixing process can be used to mix the raw materials.

[0048] For example, according to the wet mixing method, the starting materials are mixed together with a solvent and a ball that assists in grinding. The ball can be made of Si3N4, Al2O3, ZrO2, and the like. The solvent can be deionized (DI) water, an alcohol such as ethanol, or an organic solvent such as n-hexane. The starting materials can be sealed together with the solvent and the ball and mixed evenly by a mill or the like. A mixture produced by the mixing process is separated from the ball. The solvent is largely evaporated by a drying process using an oven. Powder remaining after the drying process can be uniformly ground into micrometer-sized particles using a sieve made of metal or polymer.

[0049] According to the dry blending method, the raw materials are placed in a container without a solvent and evenly mixed by a grinder. A bead can also be used to promote mixing. The dry blending method can reduce processing time compared to the wet blending method because the solvent drying step is omitted. As with the wet blending method, the powder remaining after blending the raw materials is evenly ground to the desired size using a sieve made of metal or polymer.

[0050] The mixed raw materials of each group each undergo a first sintering process. After the first sintering process, a first sintered product and a second sintered product are produced as intermediate products. The first sintered product and the second sintered product are mixed by the mixing processes described above and subjected to a second sintering process, thereby obtaining a final phosphor. In the second sintering process, an additional Si raw material or a flux may be added before mixing. The flux may facilitate movement among the first sintered product, the second sintered product, and the additional Si raw material added in the second sintering process, thereby improving the crystallinity and grain growth of the nitride-based phosphor, i.e., a final product.A sintering temperature of the second sintering process may be higher than a sintering temperature of the first sintering process. The second sintering process may be carried out under a nitrogen and oxygen gas atmosphere.

[0051] Hereinafter, a description will be given of a method for producing a nitride-based yellow phosphor prepared accordingly, which has the following composition formula: M 1-z Eu z Si a O b N c (M = Sr 1-x-y Ba x Ca y , 0 ≤ x ≤ 0.5; 0 ≤ y ≤ 0.2; 0 <z ≤ 0,3; 2 ≤ a ≤ 2,5; 1,5 ≤ b ≤ 2; und 2 ≤ c ≤ 2,5).

[0052] As described above, the first group may include the M source material containing at least one of Ca, Sr, and Ba, and the first Si source material. The second group may include the Eu source material and the second Si source material. The M source material may include a metallic carbonate (MCO3). The first Si source material may include SiO2. The Eu source material may be Eu2O3. The second Si source material may include SiO2 and Si3N4.

[0053] After mixing is complete, the raw materials of the first group are sintered at a temperature of approximately 900°C to approximately 1300°C. Sintering of the raw materials of the first group can be carried out in an air atmosphere for approximately 3 hours. The raw materials of the second group can be sintered at a temperature of approximately 1200°C to approximately 1400°C and in a nitrogen and hydrogen gas atmosphere. For example, the raw materials of the second group are also sintered for approximately 3 hours.

[0054] When the starting materials are used, a sintered product of the first group may contain M2SiO4, while a sintered product of the second group may contain EuSi2O2N2.

[0055] As described above, when the intermediates of M2SiO4 and EuSi2O2N2 are formed in advance and used as raw materials of Si and Eu, respectively, the production of impurities is suppressed. Consequently, even when the concentration of Eu increases, the nitride phosphor can be synthesized in a single phase.

[0056] The intermediate M2SiO4 is easy to synthesize in a single phase in the atmosphere. Since the intermediate M2SiO4 enables the synthesis of a solid solution containing at least two types of M ions, a nitride-based phosphor containing at least two types of M ions can also be synthesized. Another intermediate EuSi2O2N2 can suppress the increase of oxygen in a starting compound by fixing a composition ratio between Eu2O3, SiO2, and Si3N4, which are starting materials. Thus, the phosphor can be synthesized in the single phase without producing impurities. Likewise, since EuSi2O2N2 is used as the raw material of Eu, oxygen in a feed compound does not increase even if the concentration of Eu increases. Thus, the production of impurities is suppressed, and a phosphor having a composition formula M 1-z Eu z Sia O3N c (M = Sr 1-x-y Ba x Ca y ; 0 ≤ x ≤ 0.5; 0 ≤ y ≤ 0.2; 0 < z ≤ 0.3; 2 ≤ a ≤ 2.5; 1.5 ≤ b ≤ 2; and 2 ≤ c ≤ 2.5) can be generated in the single phase.

[0057] Before the second sintering process, the intermediates M2SiO4 and EuSi2O2N2 are mixed together with the additional Si source material and the flux according to the mixing method described above. The additional Si source material can be Si3N4. The flux can be NH4A (A denotes at least one of F and Cl), KB2 (K denotes at least one of Ca, Sr, and Ba, and B denotes at least one of F and Cl), LB (L denotes at least one of Na and K, and B denotes at least one of F and Cl), and the like. The flux can promote movement among M2SiO4, EuSi2O2N2, and Si3N4, thereby improving the crystallinity and grain growth of MSi2O2N2:Eu 2+is improved. Consequently, the emission intensity of the phosphor can be increased. The second sintering process can be carried out under a nitrogen and hydrogen gas atmosphere at a sintering temperature of approximately 1300°C to approximately 1600°C.

[0058] Hereinafter, a nitride-based phosphor produced by the above method will be described.

[0059] The nitride-based phosphor according to the exemplary embodiments can be expressed by the following composition formula: M 1-z Eu z Si a O3N c (M = Sr 1-x-y Ba x Ca y; 0 ≤ x ≤ 0.5; 0 ≤ y ≤ 0.2; 0 < z ≤ 0.3; 2 ≤ a ≤ 2.5; 1.5 ≤ b ≤ 2; and 2 ≤ c ≤ 2.5). The nitride-based phosphor is a single-phase yellow phosphor. With respect to the total phosphor, a concentration of an oxynitride having an atomic ratio of O / N > 1 is 1 mol / % or less. Depending on the embodiments, the nitride-based phosphor may consist essentially of only a single phase. During the manufacturing of the nitride-based phosphor according to the exemplary embodiments, an oxynitride of an impurity such as M3Si6O9N4 may not be produced. In addition, EuSi2O2N2, which is a sintered intermediate produced during manufacturing, can suppress an increase of oxygen in the starting compound by fixing the composition ratio of Eu2O3, SiO2 and Si3N4.Consequently, the phosphor can be synthesized in a single phase without producing impurities.

[0060] When driven as a light-emitting diode (LED), the nitride-based phosphor can exhibit at least 80% of the emission intensity under normal temperature conditions at approximately 150°C to approximately 200°C, which is nearly 90% of the emission intensity of a conventional yttrium aluminum garnet (YAG) phosphor. Therefore, the nitride-based phosphor exhibits excellent high-temperature stability and high emission characteristics. This means that the application characteristics of the nitride-based phosphor with respect to the LED are superior compared to the conventional YAG phosphor.

[0061] Hereinafter, a manufacturing method for a nitride-based phosphor according to exemplary embodiments will be described in detail. [Embodiments][Embodiment 1]

[0062] The present embodiment, ie, a first embodiment, proposes a method for producing a phosphor (Sr 0,75 Ba 0,25 ) 0,85 Eu 0,15 Si2O2N2. Fig. Fig. 2 is a flowchart illustrating the manufacturing method for the phosphor according to the first embodiment. The phosphor of the first embodiment is manufactured according to a sequence shown in Fig. 2 is shown. Referring to Fig.2, starting materials MCO3 (SrCO3, BaCO3) and SiO2, which belong to a first group, are mixed and sintered for approximately three hours at a temperature of approximately 1100°C under an air atmosphere, thereby obtaining a sintered intermediate product M2SiO4. Similarly, starting materials Eu2O3, SiO2, and Si3N4, which belong to a second group, are mixed and sintered for approximately three hours at a temperature of approximately 1300°C under a nitrogen and hydrogen gas atmosphere, thereby obtaining a sintered intermediate product EuSi2O2N2. Next, the sintered intermediate products M2SiO4 and EuSi2O2N2 are mixed with Si3N4, which is an additional Si starting material, and with NH4Cl, which is a flux. The mixture thus produced is again sintered at a temperature of approximately 1400°C under nitrogen and hydrogen gas atmosphere, thereby producing a phosphor having a composition formula (Sr 0,75 Ba 0,25 )0,85 Eu 0,15 Si2O2N2 as the final product. [Comparison examples][Comparison example 1]

[0063] The present comparative example also proposes a method for producing a phosphor (Sr 0,75 Ba 0,25 ) 0,85 Eu 0,15 Si2O2N2, that is, a nitride-based phosphor. However, the phosphor of the present comparative example is prepared according to a method described in Fig. 3, which differs from the method of Fig. 2. With reference to Fig.3, all the raw materials including MCO3 (SrCO3, BaCO3), SiO2, Eu2O3, and Si3N4 are simultaneously mixed and sintered at a temperature of 1400°C under nitrogen and hydrogen gas atmosphere in the same manner as in the second sintering process of the first embodiment and for about six hours, thereby obtaining a phosphor having a composition formula (Sr 0,75 Ba 0,25 ) 0,85 Eu 0,15 Si2O2N2 as the final product. [Comparison example 2]

[0064] A YAG:Ce 3+ Phosphor from Merck, which is commercially available, is used as a phosphor of the second comparative example.

[0065] Table 1 below lists the phosphors of the first embodiment, the first comparative example, and the second comparative example. [Table 1] Embodiment and comparative example fluorescent Embodiment 1 (Mr. 0,75 Ba 0,25 ) 0,85 I 0,15 Si2O2N2 Comparison example 1 (Mr. 0,75 Ba 0,25 ) 0,85 I 0,15 Si2O2N2 Comparison example 2 YAG: This 3+ Evaluation of high-temperature stability

[0066] Fig. 4 illustrates a graph showing emission intensity according to temperature with respect to the phosphor prepared in the first embodiment and the phosphor prepared in the second comparative example.

[0067] Referring to Fig. 4, at approximately 150°C to approximately 200°C, which is a general LED operating temperature, the emission intensity of the phosphor of the first embodiment is at least 80% of a normal temperature emission intensity compared to a YAG phosphor of a third comparative example. Considering that the YAG phosphor of the second comparative example has approximately 60% of the normal temperature emission intensity, it is shown that the phosphor of the first embodiment has approximately 20% superior characteristics to the YAG phosphor of the second comparative example. Evaluation of emission characteristics

[0068] Fig. 5 illustrates emission spectra of the phosphor of the first embodiment, the phosphor of the first comparative example, and the phosphor of the second comparative example.

[0069] Referring to Fig. 5, the phosphor of the first embodiment exhibits at least twice the emission intensity (integral intensity) of the phosphor of the first comparative example synthesized by the conventional solid-phase method. In addition, the phosphor of the first embodiment exhibits approximately 90% of the emission intensity of the YAG phosphor of the third comparative example. That is, the phosphor of the first embodiment has sufficient emission intensity to replace the YAG phosphor. Comprehensive evaluation

[0070] The phosphor of the first embodiment has superior emission intensity compared with the phosphor synthesized by the conventional solid-phase method in the second comparative example, and it also has superior high-temperature stability compared with the phosphor of the third comparative example. Specifically, the phosphor of the first embodiment has similar emission characteristics to the YAG phosphor while exhibiting superior high-temperature stability. That is, the phosphor of the first embodiment has high applicability to LEDs. Accordingly, the phosphor of the first embodiment is expected to stably replace the conventional YAG phosphor.

[0071] Hereinafter, the LED using the nitride-based phosphor according to exemplary embodiments will be described with reference to the accompanying drawings.

[0072] Fig.6 illustrates a sectional view illustrating a structure of a white LED according to example embodiments.

[0073] Referring to Fig. 6, the white LED using a blue LED or a long-wavelength ultraviolet (UV) LED may include a reflection cup 611, an InGaN-based LED chip 613 (GaN-based LED in the case of the long-wavelength UV LED) installed on the reflection cup 611, a yellow phosphor 617 excited by light emitted from the LED chip 613, an electrode lead 615 connected to the LED chip 613, and a light-transmitting epoxy 619 sealing the LED chip 613. The yellow phosphor 617 functions as a wavelength conversion material. The nitride-based phosphor described above may be used as the yellow phosphor 617.

[0074] The InGaN-based LED chip 613 may be connected to an external power supply through the electrode line 615. The yellow phosphor 617, which is excited by the light emitted from the InGaN-based LED chip 613, is mixed with the light-transmitting epoxy 619 and arranged on the outside of the LED chip 613. However, the LED may be, but is not limited to, the structure shown in Fig. 1, have various structures in which components are appropriately added, changed, and omitted according to the prior art. Likewise, the yellow phosphor 617 may be mixed with silicon alongside the epoxy and molded or potted around the LED chip 613, thereby forming the white LED.

[0075] That is, the yellow phosphor 617 is arranged on the outside of the LED chip 613 such that the light emitted from the LED chip 613 functions to excite the yellow phosphor 617.

[0076] Processes for forming a white light will be described in detail. A blue light emitted from the LED chip 613 passes through the yellow phosphor 617 according to the exemplary embodiments described above. A portion of the blue light excites the yellow phosphor 617, thereby forming a yellow light, while the remaining portion of the blue light passes through as it is. Thus, the white light is formed as the excited yellow light and the blue light overlap.

[0077] Hereinafter, a nitride-based phosphor prepared in the above manner will be described in detail. [Embodiment 2]

[0078] A nitride-based phosphor prepared in Embodiment 2 is a mixed-phase phosphor composed of an initial composition (Sr 0,71 Ba 0,29 )0,92 Eu 0,08 Si2O2N2 was produced. In the same manner as in Embodiment 1, the phosphor of Embodiment 2 was prepared in the order shown in Fig. 2 is illustrated.

[0079] Referring to Fig.2, starting materials MCO3 (SrCO3, BaCO3) and SiO2, belonging to a first group, are mixed and sintered for approximately three hours at a temperature of approximately 1100°C under an air atmosphere, thereby obtaining a sintered intermediate product M2SiO4. Similarly, starting materials Eu2O3, SiO2, and Si3N4, belonging to a second group, are mixed and sintered for approximately three hours at a temperature of approximately 1300°C under a nitrogen and hydrogen gas atmosphere, thereby obtaining a sintered intermediate product EuSi2O2N2. Next, the sintered intermediate products M2SiO4 and EuSi2O2N2 are mixed with Si3N4, which is an additional Si starting material, and NH4Cl, which is a flux. The thus produced mixture is again sintered at a temperature of approximately 1400°C under nitrogen and hydrogen gas atmosphere, thereby producing a mixed-phase phosphor as a final product.The phosphor prepared as described above is washed using 5% (v / v) HNO3 solution and DI water to remove impurities and an interphase. An X-ray diffraction (XRD) pattern and emission wavelength of the phosphor prepared as described above are shown in Figures . Fig. 7A and Fig. 7B shown.

[0080] Referring to Fig. 7A, since two types of main diffraction peaks are observed, it is determined that two types of XRD patterns are simultaneously exhibited. Accordingly, it can be understood that the phosphor of Embodiment 2 is a mixed-phase phosphor comprising two different phosphors.

[0081] As in Fig.7B, by exciting light of about 450 nm, which is a typical wavelength of a blue LED, the phosphor of Embodiment 2 exhibits an emission spectrum in a range of about 460 nm to 760 nm and an emission peak of about 554 nm. According to such optical properties, the phosphor of Embodiment 2 exhibits yellow emission, which means that the phosphor of Embodiment 2 has emission characteristics sufficient to replace the YAG phosphor. [Embodiment 3]

[0082] A nitride-based phosphor prepared in Embodiment 3 is a mixed-phase phosphor consisting of an initial composition (Sr 0,65 Ba 0,35 ) 0,88 Eu 0,12 Si2O2N2 is produced. In the same manner as in Embodiment 1, the phosphor of Embodiment 3 is prepared in the order shown in Fig.2 is illustrated.

[0083] Referring to Fig.2, starting materials MCO3(SrCO3, BaCO3) and SiO2, belonging to a first group, are mixed and sintered for approximately three hours at a temperature of approximately 1100°C under an air atmosphere, thereby obtaining a sintered intermediate product M2SiO4. Similarly, starting materials Eu2O3, SiO2, and Si3N4, belonging to a second group, are mixed and sintered for approximately three hours at a temperature of approximately 1300°C under a nitrogen and hydrogen gas atmosphere, thereby obtaining a sintered intermediate product EuSi2O2N2. Next, the sintered intermediate products M2SiO4 and EuSi2O2N2 are mixed with Si3N4, which is an additional Si starting material, and NH4Cl, which is a flux. The thus produced mixture is again sintered at a temperature of approximately 1400°C under nitrogen and hydrogen gas atmosphere, thereby producing a mixed-phase phosphor as a final product.The phosphor prepared as described above is washed using 5% (v / v) HNO3 solution and DI water to remove impurities and an interphase. An XRD pattern and emission wavelength of the phosphor prepared as described above are shown in Figures . Fig. 8A and Fig. 8B shown.

[0084] Referring to Fig. 8A, since two types of main diffraction peaks are observed, it is determined that two types of XRD patterns are simultaneously exhibited. Accordingly, it can be understood that the phosphor of Embodiment 3 is a mixed-phase phosphor comprising two different phosphors.

[0085] As in Fig.8B, by exciting light of about 450 nm, which is a typical wavelength of a blue LED, the phosphor of Embodiment 3 exhibits an emission spectrum in a range of about 460 nm to 760 nm and an emission peak of about 560 nm. According to such optical properties, the phosphor of Embodiment 3 exhibits yellow emission, which means that the phosphor of Embodiment 3 has emission characteristics sufficient to replace the YAG phosphor. [Embodiment 4]

[0086] A nitride-based phosphor produced in Embodiment 4 has a composition formula (Sr 0,31 Ba 0,69 ) 0,85 Eu 0,15 Si2O2N2. In the same manner as in Embodiment 1, the phosphor of Embodiment 4 is prepared in the order shown in Fig. 2 is illustrated.

[0087] Referring to Fig.2, starting materials MCO3 (SrCO3, BaCO3) and SiO2, belonging to a first group, are mixed and sintered for approximately three hours at a temperature of approximately 1100°C under an air atmosphere, thereby obtaining a sintered intermediate product M2SiO4. Similarly, starting materials Eu2O3, SiO2, and Si3N4, belonging to a second group, are mixed and sintered for approximately three hours at a temperature of approximately 1300°C under a nitrogen and hydrogen gas atmosphere, thereby obtaining a sintered intermediate product EuSi2O2N2. Next, the sintered intermediate products M2SiO4 and EuSi2O2N2 are mixed with Si3N4, which is an additional Si starting material, and NH4Cl, which is a flux. The mixture thus produced is again sintered at a temperature of approximately 1400°C under nitrogen and hydrogen gas atmosphere, producing a single-phase phosphor having a composition formula (Sr 0,31 Ba0,69 ) 0,85 Eu 0,15 Si2O2N2 as the final product. Next, the thus prepared phosphor is washed using 5% (v / v) HNO3 solution and DI water to remove impurities and an intermediate phase. An XRD pattern and emission wavelength of the above-prepared phosphor are shown in the Fig. 9A and Fig. 9B.

[0088] Referring to Fig. 9A, since a single type of main diffraction peak is observed, it is determined that the XRD pattern is shown according to a single phase. Accordingly, it can be understood that the phosphor of Embodiment 4 is a single-phase phosphor.

[0089] As in Fig.9B, by exciting light of about 450 nm, which is a typical wavelength of a blue LED, the phosphor of Embodiment 4 exhibits an emission spectrum in a range of about 465 nm to 765 nm and an emission peak of about 577 nm. According to such optical properties, the phosphor of Embodiment 4 exhibits yellow emission, which means that the phosphor of Embodiment 4 has emission characteristics sufficient to replace the YAG phosphor. [Embodiment 5]

[0090] A nitride-based phosphor produced in Embodiment 5 is a single-phase phosphor having a composition formula (Sr 0,35 Ba 0,65 ) 0,85 Eu 0,15 Si2O2N2. In the same manner as in Embodiment 1, the phosphor of Embodiment 5 is prepared in the order shown in Fig. 2 is illustrated.

[0091] Referring to Fig.2, starting materials MCO3 (SrCO3, BaCO3) and SiO2, belonging to a first group, are mixed and sintered for approximately three hours at a temperature of approximately 1100°C under an air atmosphere, thereby obtaining a sintered intermediate product M2SiO4. Similarly, starting materials Eu2O3, SiO2, and Si3N4, belonging to a second group, are mixed and sintered for approximately three hours at a temperature of approximately 1300°C under a nitrogen and hydrogen gas atmosphere, thereby obtaining a sintered intermediate product EuSi2O2N2. Next, the sintered intermediate products M2SiO4 and EuSi2O2N2 are mixed with Si3N4, which is an additional Si starting material, and NH4Cl, which is a flux. The mixture thus produced is again sintered at a temperature of approximately 1400°C under nitrogen and hydrogen gas atmosphere, producing a single-phase phosphor having a composition formula (Sr 0,35 Ba0,65 ) 0,85 Eu 0,15 Si2O2N2 as the final product. Next, the prepared phosphor is washed using 5% (v / v) HNO3 solution and DI water to remove impurities and an intermediate phase. Data from a crystal structure analysis of the above-prepared phosphor are shown in Table 2. A Rietveld fit result of the phosphor is shown in Fig. 10 shown. [Table 2] radiation Synchrotron X-ray radiation (λ = 0.412463 Å Diffraction angle (2Θ) range / step 2°-32° / 0,001° Number of data points 30000 formula (Mr. 0,35 Ba 0,65 ) 0,85 I 0,15 Si2O2N2 X-ray density 4,06 g / cm 3 Crystal system triclin Space group P1 (number 1) Lattice parameters a=7.2138 Å; b=7.4084 Å; c=7.3368 Å; α = 88.77°; β = 84.44°; γ = 75.80° Cell volume 378,32 Å 3 (Z =4) Number of reflections 1881 R-factors R Wp = 10.8%, R p = 7.2%, R F2 = 4.9%, x = 2.1

[0092] Referring to Table 2, it can be understood that the nitride-based phosphor prepared in Embodiment 5 has a triclinic crystal system and a space group P1.

[0093] Referring to Fig. 10, an XRD pattern of the nitride-based phosphor of Embodiment 5 almost corresponds to a calculated value. Accordingly, it can be determined that the phosphor of Embodiment 5 is a single-phase phosphor.

[0094] In Fig. 10, “obs” refers to a measured value of the manufactured phosphor, “cal” refers to a calculated value obtained by calculation, and “diff (obs-cal)” refers to a value obtained by subtracting the calculated value from the measured value, from which a degree of purity of the manufactured phosphor can be determined. [Embodiments 6 to 26]

[0095] Embodiments 6 to 26 relate to phosphors having a composition formula of (Sr 1-m Ba m )Si2O2N2, where "m" is 0; 0.05; 0.1; 0.15; 0.2; 0.25; 0.3; 0.35; 0.4; 0.45; 0.5; 0.55; 0.6; 0.65; 0.7; 0.75; 0.8; 0.85; 0.9; 0.95; and 1, respectively. In the same manner as in Embodiment 1, the phosphors of Embodiments 6 to 26 are prepared in the order shown in Fig. 2 is illustrated.

[0096] Referring to Fig. 2, starting materials MCO3 (SrCO3, BaCO3) and SiO2, which belong to a first group, are mixed and sintered for about three hours at a temperature of about 1100°C under an air atmosphere, thereby obtaining a sintered intermediate product M2SiO4. Here, since Eu is not included, a process of synthesizing another sintered intermediate product EuSi2O2N2 is omitted. Next, the sintered intermediate products M2SiO4 are mixed with Si3N4, which is an additional Si starting material, and NH4Cl, which is a flux. The thus-produced mixture is again sintered at a temperature of about 1400°C under a nitrogen and hydrogen gas atmosphere, thereby producing a phosphor having a composition formula (Sr 1-m Ba m)Si2O2N2 (where “m” has values between 0 and 1, as mentioned above) as the final product. Next, the prepared phosphor is washed using 5% (v / v) HNO3 solution and DI water, thereby removing impurities and an intermediate phase. XRD patterns of the above-prepared phosphors are shown in Fig. 11 shown.

[0097] Referring to Fig. 11, the XRD patterns change regularly according to an increase in the Ba content. Thus, differences in a crystal phase can be distinguished according to the increase in the Ba content. Changes in the crystal phase according to a range of Ba content are shown in Table 3. [Embodiments 27 to 41]

[0098] Embodiments 27 to 41 relate to phosphors having a composition formula (Sr 1-m Ba m ) 1-n Eu nSi2O2N2, in which values of (m, n) are (0; 0.02), (0.3; 0.2), (0.4; 0.15), (0.6; 0.1), (0.6; 0.2), (0.7; 0.05), (0.8; 0.02), (0.8; 0.05), (0.8; 0.1), (0.8; 0.15), (0.8; 0.2), (0.9; 0.1), (1; 0.02), (1; 0.1), and (1; 0.15), respectively. In the same manner as in Embodiment 1, the phosphors of Embodiments 27 to 41 are prepared in the order shown in Fig. 2 is illustrated.

[0099] Referring to Fig.2, starting materials MCO3 (SrCO3, BaCO3) and SiO2, belonging to a first group, are mixed and sintered for approximately three hours at a temperature of approximately 1100°C under an air atmosphere, thereby obtaining a sintered intermediate product M2SiO4. Similarly, starting materials Eu2O3, SiO2, and Si3N4, belonging to a second group, are mixed and sintered for approximately three hours at a temperature of approximately 1300°C under a nitrogen and hydrogen gas atmosphere, thereby obtaining a sintered intermediate product EuSi2O2N2. Next, the sintered intermediate products M2SiO4 and EuSi2O2N2 are mixed with Si3N4, which is an additional Si starting material, and NH4Cl, which is a flux. The mixture thus produced is again sintered at a temperature of approximately 1400°C under nitrogen and hydrogen gas atmosphere, producing a single-phase phosphor having a composition formula (Sr 1-m Bam ) 1-n Eu n Si2O2N2 (where m and n have the values mentioned above) as the final product. Next, the thus prepared phosphor is washed using 5% (v / v) HNO3 solution and DI water, thereby removing impurities and an intermediate phase. XRD patterns and emission spectra of the phosphors are shown in the Fig. 12A and Fig. 12B shown.

[0100] Referring to Fig. 12A, the XRD patterns are periodically changed according to the Ba and Eu contents. Thus, differences in a crystal phase can be distinguished according to the Ba and Eu contents. Changes in the crystal phase according to a range of Ba and Eu contents are shown in Table 4.

[0101] In addition, with reference to Fig. 12B, the emission wavelength was changed according to the contents of Ba and Eu according to the changes in the XRD pattern.

[0102] Furthermore, as a result of the analysis of phases, emission peak wavelengths Wp of the phosphors prepared in Embodiments 27 to 41 are shown in Table 4. Also, changes in phase according to the range of m and n values from the XRD patterns of the phosphors prepared in Embodiments 6 to 26 and Embodiments 27 to 41 are shown in Table 3. [Table 3] <h2 style=";text-align:left;direction:ltr">(Sr<h2 style=";text-align:left;direction:ltr"> 1-m <h2 style=";text-align:left;direction:ltr"> Ba<h2 style=";text-align:left;direction:ltr"> m <h2 style=";text-align:left;direction:ltr"> )Si2O2N2 (Mr. 1-m Ba m ) 1-n I n Si2O2N- phase m=0 m=0 and n=0 SrSi2O2N2 0<m<0,25 0 < m ≤ 0.3 and 0 < m*(1-n) < 0.25 (Sr 1-m Ba m ) 1-n Eu n Si2O2N2 solid solution (→ SrSi2O2N2 type:A phases) 0,25 ≤ m < 0,5 0.3 < m ≤ 0.6 and 0.25 ≤ m*(1-n) < 0.5 A-phases + B-phases 0,5 < m < 0,65 0.6 ≤ m ≤ 0.8 and 0.5 ≤ m*(1-n) < 0.65 (Sr 1-m Ba m ) 1-n Eu n Si2O2N2 solid solution (→ SrSi2O2N2 type:B phases) 0,65 ≤ m < 0,7 0.7 ≤ m ≤ 0.8 and 0.65 ≤ m*(1-n) < 0.7 B-phases + C-phases 0,7 ≤ m < 0,75 0.8 ≤ m ≤ 0.9 and 0.7 ≤ m*(1-n) < 0.75 (Sr 1-m Ba m ) 1-n Eu n Si2O2N2 solid solution (→ unknown type: C phases) 0,75 ≤ m < 0,8 0.8 ≤ m ≤ 0.9 and 0.75 ≤ m*(1-n) < 0.8 C-phases + D-phases 0,8 < m < 1 0.9 ≤ m ≤ 1 and 0.8 ≤ m*(1-n) < 1 (Sr 1-m Ba m ) 1-n Eu n Si2O2N2 solid solution (→ BaSi2O2N2 type: D-phases) m=1 m=1 and n=0 BaSi2O2N2 [Table 4] Embodiments (Mr. 1-m Ba m ) 1-n I n Si2O2N2 Phases PL Wp(nm) 27 m=0 and n=0.02 (Sr 1-m Ba m ) 1-n Eu n Si2O2N2 solid solution (→ SrSi2O2N2 type:A phases) 535 28 m=0.3 and n=0.2 (Sr 1-m Ba m ) 1-n Eu n Si2O2N2 solid solution (→ SrSi2O2N2 type:A phases) 560 29 m=0.4 and n=0.15 A-phases + B-phases 560 30 m=0.6 and n=0.2 A-phases + B-phases 577 31 m=0.6 and n=0.1 (Sr 1-m Ba m ) 1-n Eu n Si2O2N2 solid solution (→ SrSi2O2N2 type:B phases) 565 32 m=0.8 and n=0.2 (Sr 1-m Ba m ) 1-n Eu n Si2O2N2 solid solution (→ SrSi2O2N2 type:B phases) 579 33 m=0.7 and n=0.05 B-phases + C-phases 473, 566 34 M=0.8 and n=0.15 B-phases + C-phases 479, 577 35 m=0.8 and n=0.1 (Sr 1-m Ba m ) 1-n Eu n Si2O2N2 solid solution (→ unknown type: C phases) 477, 578 36 m=0.8 and n=0.05 C-phases + D-phases 483, 579 37 m=0.8 and n=0.02 C-phases + D-phases 492, 567 38 m=0.9 and n=0.1 (Sr 1-m Ba m ) 1-n Eu n Si2O2N2 solid solution (→ BaSi2O2N2 type: D-phases) 495, 575 39 m=1 and n=0.15 (Sr 1-m Ba m ) 1-n Eu n Si2O2N2 solid solution (→ BaSi2O2N2 type: D-phases) 497, 583 40 m=1 and n=0.1 (Sr 1-m Ba m ) 1-n Eu n Si2O2N2 solid solution (→ SrSi2O2N2 type:B phases) 498, 590 41 m=1 and n=0.02 (Sr 1-m Ba m ) 1-n Eu n Si2O2N2 solid solution (→ BaSi2O2N2 type: D-phases) 494

[0103] Referring to Tables 3 and 4, a plurality of phases exist mixed. In general phosphors, changes in a plurality of phases rarely occur, and the changes according to the ratio of Sr and Ba between Sr and Ba occur. However, the embodiments of the present invention exhibit changes in a plurality of phases.

[0104] Furthermore, the overall XRD pattern remains constant even with changes in the m and n values. It can also be understood that the phase is a fixed solution when the structures are similar even though a diffraction angle (2Θ) changes slightly.

Claims

[1] A method of producing a nitride-based phosphor, the method comprising: a first sintering process to divide a plurality of starting materials into at least two groups and to sinter the respective groups; and a second sintering process to mix and sinter products produced after sintering the respective groups, whereby at least one of the plurality of starting materials is contained in each of the at least two groups, and the starting materials Eu, Si, O and M, which is at least one of Ca, Sr and Ba. [2] The method according to claim 1, wherein a sintering temperature in the second sintering process is higher than a sintering temperature in the first sintering process. [3] The method according to claim 1, wherein the second sintering process is carried out under nitrogen and hydrogen gas atmosphere. [4] A method for producing a phosphor expressed by the following composition formula: M 1-z Eu z Si a O3N c (M = Sr 1-x-y Ba x Ca y ; 0≤x≤0.5; 0≤y≤0.2; 0 < z ≤ 0.3; 2 ≤ a ≤ 2.5; 1.5 ≤ b ≤ 2; and 2 ≤ c ≤ 2.5), the method comprising: a first sintering process comprising sintering a first mixture to produce a first sintered product by mixing and sintering a first raw material group containing an M raw material and a first Si raw material, and sintering a second mixture to produce a second sintered product by mixing and sintering a second raw material group containing an Eu raw material and a second Si raw material; and a second sintering process for mixing and sintering the first sintered product and the second sintered product. [5] The method of claim 4, wherein the first sintering process comprises: producing the first sintered product by mixing and sintering the first raw material group containing MCO3 and SiO2; and producing the second sintered product by mixing and sintering the second group containing Eu2O3, SiO2 and Si3N4. [6] The method of claim 4, wherein the sintering of the first mixture is carried out at a temperature of about 900°C to about 1300°C. [7] The method of claim 4, wherein the sintering of the second mixture is carried out at a temperature of about 1200°C to about 1400°C. [8] The method of claim 4, wherein the sintering adds a silicon nitride compound to the second mixture. [9] The method of claim 5, wherein the sintering adds Si3N4 to the second mixture. [10] The method according to claim 4, wherein the sintering adds to the second mixture at least one of NH4A, where A denotes at least one of F and Cl, KB2, where K denotes at least one of Ca, Sr and Ba and B denotes at least one of F and Cl, and LB, where L denotes at least one of Na and K and B denotes at least one of F and Cl. [11] The method according to claim 4, wherein the sintering of the second mixture is carried out under a nitrogen and hydrogen gas atmosphere. [12] The method of claim 4, wherein the sintering of the second mixture is carried out at a temperature of about 1300°C to about 1600°C. [13] The method according to claim 4, wherein the first sintered product comprises a solid solution containing at least two kinds of M ions. [14] The method of claim 4, wherein the second sintered product comprises EuSi2O2N2. [15] A phosphor in a single phase expressed by a composition formula M 1-z Eu z Si a O3N c (M = Sr 1-x-y Ba x Ca y , 0 ≤ x ≤ 0.5; 0 ≤ y ≤ 0.2; 0 < z ≤ 0.3; 2 ≤ a ≤ 2.5; 1.5 ≤ b ≤ 2; and 2 ≤ c ≤ 2.5), produced by the method for producing a phosphor according to any one of claims 4 to 14, wherein a concentration of an oxynitride having an atomic ratio of O / N > 1 is 1 mol / % or less with respect to the entire phosphor. [16] The phosphor of claim 15, wherein, when a light-emitting diode (LED) is driven, the phosphor has at least 80% emission intensity of an emission intensity under normal temperature at a temperature of about 150°C to about 200°C. [17] White light-emitting diode (LED), which contains a phosphor in a single phase, which is represented by the composition formula M 1-z Eu z Sia O3N c (M = Sr 1-x-y Ba x Ca y , 0≤x≤0.5; 0≤y≤0.2; 0 < z ≤ 0.3; 2 ≤ a ≤ 2.5; 1.5 ≤ b ≤ 2; and 2 ≤ c ≤ 2.5), produced by the method for producing a phosphor according to any one of claims 4 to 14, as a yellow phosphor which is a wavelength conversion material, wherein the concentration of an oxynitride having an atomic ratio of O / N > 1 is 1 mol / % or less with respect to the entire phosphor. [18] The white LED according to claim 17, wherein the white LED has at least 80% emission intensity of an emission intensity under normal temperature at a temperature of about 150°C to 200°C. [19] Nitride-based phosphor as a phosphor represented by a composition formula M 1-n Eu n Si a O b N c (M = Sr 1-m Ba m; 0.25 < m ≤ 0.3; 0 < m×(1-n) < 0.25; 2 ≤ a ≤ 2.5; 1.5 ≤ b ≤ 2; and 2 ≤ c ≤ 2.5), produced by the method for producing a nitride-based phosphor according to any one of claims 1 to 3, wherein the concentration of an oxynitride having an atomic ratio of O / N > 1 is 0.01 mol / % or less with respect to the entire phosphor. [20] The nitride-based phosphor of claim 19, wherein the phosphor has a triclinic crystal system and a space group P1. [21] The nitride-based phosphor according to claim 19, wherein the phosphor forms a completely solid solution in a Sr-Eu system or a Sr-Ba-Eu system. [22] The nitride-based phosphor according to claim 19, wherein diffraction angles with respect to three diffraction peaks having high intensity are respectively in a range of 12.50 ≤ 2θ ≤ 12.60; 25.16 ≤ 2θ ≤ 25.30; and 31.51 ≤ 2θ ≤ 31.65 in an X-ray diffraction (XRD) pattern of the phosphor. [23] The nitride-based phosphor of claim 19, wherein the phosphor has an emission wavelength in a range of 460 nm to 750 nm. [24] Nitride-based phosphor as a single-phase phosphor expressed by a composition formula M 1-n Eu n Si a O b N c (M=Sr 1-m Ba m; 0.6 ≤ m ≤ 0.8; 0.5 ≤ m×(1-n) < 0.65; 2 ≤ a ≤ 2.5; 1.5 ≤ b ≤ 2; and 2 ≤ c ≤ 2.5), produced by the method for producing a nitride-based phosphor according to any one of claims 1 to 3, wherein the concentration of an oxynitride having an atomic ratio of O / N > 1 is 0.01 mol / % or less with respect to the entire phosphor. [25] The nitride-based phosphor of claim 24, wherein the phosphor has a triclinic crystal system and a space group P1. [26] The nitride-based phosphor of claim 24, wherein the phosphor forms a completely solid solution in a Sr-Ba-Eu system. [27] The nitride-based phosphor according to claim 24, wherein diffraction angles with respect to four diffraction peaks having a high intensity are respectively in a range of 12.30 ≤ 2θ ≤ 12.38; 24.75 ≤ 2θ ≤ 24.88; 25.56 ≤ 2θ ≤ 25.62; and 31.09 ≤ 2θ ≤ 31.25 in an X-ray diffraction (XRD) pattern of the phosphor. [28] The nitride-based phosphor of claim 24, wherein the phosphor has an emission wavelength in a range of 465 nm to 765 nm. [29] Nitride-based phosphor as a mixed-phase phosphor generated from an initial composition M 1-n Eu n Si a O b N c (M = Sr 1-m Ba m ; 0.3 ≤ m ≤ 0.6; 0.25 ≤ m×(1-n) < 0.5; 2 ≤ a ≤ 2.5; 1.5 ≤ b ≤ 2; and 2 ≤ c ≤ 2.5), produced by the method for producing a nitride-based phosphor according to any one of claims 1 to 3, wherein the concentration of an oxynitride having an atomic ratio of O / N > 1 is 0.01 mol / % or less with respect to the entire phosphor. [30] Nitride-based phosphor according to claim 29, wherein the phosphor has two different phases having a triclinic crystal system and a space group P1. [31] A nitride-based phosphor according to claim 29, wherein the phosphor has two distinct phases forming a complete solid solution in a Sr-Ba-Eu system. [32] The nitride-based phosphor according to claim 31, wherein in an X-ray diffraction (XRD) pattern of the phosphor, one of the two different phases has diffraction angles with respect to three diffraction peaks having a high intensity, the diffraction angles being respectively in a range of 12.47 ≤ 2θ ≤ 12.49; 25.13 ≤ 2θ ≤ 25.15 and 31.48 ≤ 2θ < 31.50, and the other one of the two different phases has diffraction angles with respect to three diffraction peaks having a high intensity, the diffraction angles being respectively in a range of 12.39 ≤ 2θ ≤ 12.45; 24.89 ≤ 2θ ≤ 24.95 and 31.26 ≤ 2θ ≤ 31.

41. [33] The nitride-based phosphor of claim 29, wherein the phosphor has an emission wavelength in a range of 460 nm to 760 nm.

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