KR101820597B1 - Y7O6F9:Ce3+ - Tb3+ Phosphors - Google Patents

Abstract

The present invention relates to a phosphor for LEDs. The phosphor includes Y_7O_6F_9:Ce^3+-Tb^3+ and has a Ce^3+ sensitizer and an activating agent (Tb^3+) doped onto the non-stoichiometric yttrium oxyfluoride (Y_7O_6F_9) matrix to enhance the green light emitting performance at near-UV excitation. According to the present invention, the phosphor for LEDs is configured by doping Ce^3+ and Tb^3+ on the yttrium oxyfluoride (Y_7O_6F_9) matrix at the same time.

Description

Y7O6F9: Ce3 + - Tb3 + phosphor {Y7O6F9: Ce3 + - Tb3 + Phosphors}

The technical idea of the present invention relates to a phosphor for LED, and relates to a phosphor for LED including Y ₇ O ₆ F ₉ : Ce ^{3 +} -Tb ^{3 +} having enhanced green emission intensity and a method for manufacturing the same.

LED-based white light-emitting diodes (LEDs) can be realized by combining a blue LED chip (450 nm) with a yellow phosphor (for example, Y ₃ Al ₅ O ₁₂ : Ce) A green-red phosphor or a green-red-blue phosphor may be combined with a near UV LED chip. Therefore, it is essential to use a phosphor material for white LED light. This phosphor-based white LED technology is a next-generation product technology for environmentally friendly energy saving, and core technologies related to phosphors are needed to secure market leadership. For example, YAG: Ce is a typical yellow phosphor as a phosphor for use in a blue LED, and nitride-based phosphors have been actively researched recently.

On the other hand, development of typical white and RGB phosphor materials such as YAG as near-ultraviolet LED-based phosphor is not yet developed and intensive development is needed. Near-ultraviolet LEDs can emit relatively high intensity energy to blue-LEDs, and thus can be applied to medical and optical conversion devices. Therefore, it is required to develop a high-efficiency phosphor material through non-stoichiometric material synthesis and more active energy transfer mechanism research. In particular, it is required to develop a phosphor for high-efficiency green emission in near-ultraviolet excitation.

1. Korean Patent Publication No. 10-2013-0122383 2. Korean Patent Publication No. 10-2011-0129972

1. Y. Shimizu, K. Sakano, Y. Noguchi and T. Moriguchi, U.S. Pat., 5,998,925, 1999. 2. S. Ye, F. Xiao, Y. X. Parn, Y. Y. Ma and Q. Y. Zhang, Mater. Sci. Eng., R, 2010, 71, 1-34. 3. Y. Kim and S. Park, Mater. Res. Bull., 2014, 49, 469-474. 4. W. J. Yang, L. Luo, T. M. Chen and N. S. Wang, Chem. Mater., 2005,17, 3883-3888. 5. K. H. Kwon, W. B. Im, H. S. Jang, H. S. Yoo and D. Y. Jeon, Inorg. Chem., 2009, 48, 11525-11532. 6. Y. Uchida and T. Taguchi, Opt. Eng., 2005, 44 (12), 124003-124009. 7. G. Li, D. Geng, M. Shang, Y. Zhang, C. Peng, Z. Cheng and J. Lin, J. Phys. Chem. C, 2011, 115, 21882-21892. 8. W. Lu, N. Guo, Y. Jia, Q. Zhao, W. Lv, M. Jiao, B. Shao and H. You, Inorg. Chem., 2013, 52, 3007-3012. 9. M. A. Mickens and Z. Assef, J. Lumin., 2014, 145, 498-506. 10. Y. Liu, X. Zhang, Z. Hao, X. Wang and J. Zhang, Chem. Commun., 2011, 47, 10677-10679. 11. X. Zhang and M. Gong, Mater. Lett., 2011, 65, 1756-1758. 12. S. Park, Mater. Lett., 2014, 135, 59-62. 13. Z. Xia and R. S. Liu, J. Phys. Chem. C, 2012, 116, 15604-15609. 14. X. Fu, L. Fang, S. Niu and H. Zhang, J. Lumin., 2013, 142, 163-166. 15. S. Lee and S. Park, J. Lumin., 2013, 143, 215-218. 16. V. Pankratov, A. I. Popov, S. A. Chernov, A. Zharkouskaya and C. Feldmann, Phys. Status Solidi B, 2010, 247, 2252-2257. 17. R. Sato, S. Takeshita, T. Isobe, T. Sawayama and S. Niikura, ECS J. Solid State Sci. Technol., 2012,1, R163-R168. 18. D. J. M. Bevan, J. Mohyla, B. F. Hoskins and R. J. Steen, Eur. J. Solid State Inorg. Chem., 1990, 27, 451-465. 19. S. Park, J. Lumin., 2015, 166, 176-179. 20. G. Blasse, Philips Res. Rep., 1969, 24, 131-144. 21. N. Guo, Y. Huang, H. You, M. Yang, Y. Song, K. Liu and Y. Zheng, Inorg. Chem., 2010, 49, 10907-10913. 22. S. Park, W. Yang, C. Y. Park, M. Noh, S. Choi, D. Park, H. S. Jang and S. H. Cho, Mater. Res. Bull., 2015, 71, 25-29. 23. W. J. Yang, L. Luo, T. M. Chen and N. S. Wang, Chem. Mater., 2005,1, 3883-3888. 24. Y. Zhang, G. Li, D. Geng, M. Shang, C. Peng and J. Lin, Inorg. Chem., 2012, 51, 11655-11664.

The technical problem to be solved by the technical idea of the present invention is that the non-stoichiometric yttrium oxyfluoride (Y ₇ O ₆ F ₉ ) host is doped with Ce ³⁺ and Tb ³⁺ , And a method for producing the phosphor.

However, these problems are illustrative, and the technical idea of the present invention is not limited thereto.

According to an aspect of the present invention, there is provided a phosphor for an LED comprising a yttrium oxyfluoride (Y ₇ O ₆ F ₉ ) host doped with Ce ^{3 +} and Tb ^{3 +} .

In some embodiments of the present invention, the phosphor may comprise a compound of the following formula (1).

[Chemical Formula 1]

Y _{7 (1-mn)} Ce _7m Tb _7n O ₆ F ₉

(M = 0 to 0.1, n = 0 to 0.15 in the above formula (1)

In some embodiments of the present invention, the phosphor may be excited using near ultraviolet light.

In some embodiments of the present invention, the phosphor may emit light by energy transfer from the Ce ^{3 +} to the Tb ^{3 +} .

In some embodiments of the present invention, the phosphor may exhibit a maximum green light emission intensity at m = 0.01 and n = 0.15.

In some embodiments of the present invention, the phosphor may exhibit a maximum green light emission intensity at n = 0.1 when m = 0.05.

In some embodiments of the present invention, the phosphor may exhibit a maximum green light emission intensity at n = 0.1 when m = 0.1.

In some embodiments of the present invention, the phosphor may have dipole-dipole interactions as a dominant energy transfer mechanism.

In some embodiments of the present invention, the matrix is Y ₇ O ₆ F ₉ And may include a vernier image.

According to an aspect of the present invention, there is provided a phosphor for an LED comprising a yttrium oxyfluoride (Y ₇ O ₆ F ₉ ) host doped with Tb ³⁺ and a compound represented by the following formula (2).

 (2)

Y _{7 (1-n)} Tb _7n O ₆ F ₉

(N = 0 to 0.15 in the above formula (2)

In some embodiments of the present invention, the phosphor may exhibit a maximum green light emission intensity at n = 0.1.

In some embodiments of the present invention, the phosphor is from ⁵ D ₄ of the Tb ^{3 +} can emit green by a transition to the ⁷ F _5.

According to an aspect of the present invention, there is provided a method of manufacturing a LED-use phosphor according to the following Formula 1, wherein Y ₂ O ₃ , CeO ₂ , Tb ₄ O ₇ , and NH Quantifying and mixing the starting material of the ₄ F flux to form a mixture; And calcining and crystallizing the mixed material.

[Chemical Formula 1]

Y _{7 (1-mn)} Ce _7m Tb _7n O ₆ F ₉

(M = 0 to 0.1, n = 0 to 0.15 in the above formula (1)

In some embodiments of the present invention, the NH ₄ F flux may be provided in the form of a pellet to prevent it from being lost to ammonia and flourine gas.

In some embodiments of the present invention, the crystallization step is performed in a temperature range of 1000 ° C to 1100 ° C for 1 to 3 hours under an atmosphere of 2% to 6% H ₂ and 94 to 98% Ar .

In some embodiments of the present invention, the sum of the molar numbers of Y ³⁺ ions of Y ₂ O ₃ , Ce ³⁺ ions of CeO ₂ , and Tb ³⁺ ions of Tb ₄ O ₇ and the NH ₄ The molar ratio of F may be 1: 2.

The phosphor for LED according to the technical idea of the present invention is a phosphor in which Ce ³⁺ (sensitizer) and Tb ³⁺ (activator) are doped in the non-stoichiometric yttrium oxyfluoride (Y ₇ O ₆ F ₉ ) ≪ / RTI > Unlike the conventional phosphors, the emission intensity of green is significantly increased by the energy transfer from Ce ³⁺ ions to Tb ³⁺ ions.

The phosphor may be used singly as a green phosphor, or may be used in combination of RGB, or may be used in various LEDs for a white LED. In particular, the phosphors can be used for LEDs excited by near ultraviolet rays.

The effects of the present invention described above are exemplarily described, and the scope of the present invention is not limited by these effects.

1 is a graph showing an X-ray diffraction pattern of a phosphor for LED according to an embodiment of the present invention.
2 is a graph showing excitation and emission spectrum of a phosphor for LED according to an embodiment of the present invention.
FIG. 3 is a graph showing the relative light emission intensity according to the Tb ³⁺ ion content of the LED-use fluorescent material according to an embodiment of the present invention.
FIG. 4 is a graph showing excitation and emission spectrum of a phosphor for LED according to an embodiment of the present invention.
FIG. 5 is a graph showing the relative emission intensity according to Ce ^{3 +} ion content of the LED-use fluorescent material according to an embodiment of the present invention.
FIG. 6 is a graph showing the emission spectrum of a phosphor for LED according to an embodiment of the present invention.
7 is a graph showing the emission spectrum of the LED-use phosphor according to an embodiment of the present invention.
8 is a graph showing the energy transfer efficiency according to the Tb ³⁺ ion content of the LED phosphor according to an embodiment of the present invention.
9 to 11 are graphs illustrating the energy transfer mechanism of the LED phosphor according to an embodiment of the present invention.
12 is a graph showing the excitation and emission spectrum of a phosphor for LED according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. It will be apparent to those skilled in the art that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the invention to those skilled in the art. The scope of technical thought is not limited to the following examples. Rather, these embodiments are provided so that this disclosure will be more thorough and complete, and will fully convey the scope of the invention to those skilled in the art. The same reference numerals denote the same elements at all times. Further, various elements and regions in the drawings are schematically drawn. Accordingly, the technical spirit of the present invention is not limited by the relative size or spacing depicted in the accompanying drawings.

The technical idea of the present invention relates to a phosphor for a light emitting diode (LED), and specifically relates to a Y ₇ O ₆ F ₉ : Ce ^{3 +} -Tb ^{3 +} phosphor having an enhanced green emission intensity.

The white light emitting diodes are formed by the combination of a blue LED chip (450 nm) and a yellow phosphor (Y ₃ Al ₅ O ₁₂ : Ce), or a near-ultraviolet LED chip and a green-red phosphor (Ba ₉ Y ₂ Si ₆ O ₂₄ : Eu, Mn, CaAl ₂ Si ₂ O ₈ : Eu, Mn, or (CaMg) ₆ - (PO ₄ ) ₄ : Eu, Mn. In addition, near-ultraviolet (NUV) chips combined with red-green-blue (RGB) phosphors can realize white LED light, and in particular, realize cooperating luminosities with phosphors that change color, Safety can be shown.

As the RGB phosphors, for example, Mg ₂ Y ₈ (SiO ₄ ) ₆ O ₂ : Ce, Tb, Mn, CaScAlSiO ₆ : Ce, Tb, Mn, or Na ₂ Ca ₃ Si ₆ O ₁₆ : Ce , Tb, Mn "and the like. These phosphors can exhibit an energy transfer mechanism between Ce ^{3 +} and Tb ^{3 +} or an energy transfer mechanism between Ce ^{3 +} and Mn ^{2 +} in various host materials. One of the rare earth material Ce ^{3 +} ions because of the wide emission band, which is caused by the 5d-4f transition represents the effective absorption can be effectively used as a sensitizer (sensitizer). However, Mn ²⁺ activator ions, which can affect the dd transition ( ⁴ T ₁ -> ⁶ A ₁ ), are generally difficult to monitor because of the inhibition of electrical dipole interactions. As the multipole interaction is made by the electrostatic energy transfer between Ce ^{3 +} and Mn ^{2 +} , the release of Mn ^{2 +} ions as an activator can be further increased. Also, the Tb ^{3 +} ions are very weak in the absorption peaks because ff transitions are inhibited in the near ultraviolet region.

On the other hand, when energy transfer from Ce ³⁺ to Tb ³⁺ occurs effectively, the transition of T D ³⁺ emission peaks to ⁵ D ₄ -> ⁷ F _J predominates. That is, excitation of the Ce ³⁺ ions from the ground state to the 5d state occurs, followed by an energy transfer process of ⁵ D ₃ and other levels of Tb ³⁺ ions, resulting in a strong green emission . Therefore, a green light emitting compound capable of causing energy transfer between Ce ^{3 +} and Tb ^{3 +} can be used as a phosphor for near-ultraviolet LED. Thus, various base materials such as silicates, phosphates, and borates, etc. can be used in combination with Ce ³⁺ and Tb ³⁺ ions to achieve effective green emission in white LED devices have.

The Y ₇ O ₆ F ₉ : Ce ³⁺ -Tb ³⁺ phosphor according to the present invention is a phosphor which has a non-stoichiometric (ie Y: O: F ≠ 1: 1: 1) oxyfluoride (Y ₇ O ₆ F ₉ ) Can be realized by doping Ce ³⁺ ions as a sensitizer and Tb ³⁺ ions as an activator. Wherein _{Y 7 O 6 F 9: Ce} 3+ -Tb 3+ phosphor may implement a combination of green to yellow emitted from the blue and Tb ³⁺ coming from Ce ^3+, in particular, Tb ³⁺ ions from the Ce ³⁺ ion The light emission intensity can be remarkably increased by the energy transfer to the light emitting layer.

The phosphor for LED according to the technical idea of the present invention is composed of yttrium oxyfluoride (Y ₇ O ₆ F ₉ ) host doped with Ce ^{3 +} as a sensitizer and doped with Tb ³⁺ as an activator . The LED fluorescent material may be formed by replacing yttrium with cerium (Ce) and terbium (Tb) from a yttrium oxyfluoride (Y ₇ O ₆ F ₉ ) host. For example, the LED-use fluorescent substance may include a compound represented by the following formula (1).

[Chemical Formula 1]

Y _{7 (1-mn)} Ce _7m Tb _7n O ₆ F ₉

(M = 0 to 0.1, n = 0 to 0.15 in the above formula (1)

In addition, the LED phosphor may comprise a compound of formula (2) of yttrium oxy-fluoride (Y ₇ O ₆ F ₉₎ and yttrium from the matrix can be formed by terbium (Tb) is substituted for,.

(2)

Y _{7 (1-n)} Tb _7n O ₆ F ₉

(N = 0 to 0.15 in the above formula (2)

It is made of the yttrium oxy-fluoride (Y ₇ O ₆ F ₉₎ the matrix is a one-dimensional second structure of peulrorayiteu (fluorite) having a unit cell having a non-stoichiometric structures, "a × 7b × c" , the Abm2 space group May be referred to as a vernier. Specifically, the yttrium oxy-fluoride (Y ₇ O ₆ F ₉₎ Matrix, Y ₇ O ₆ F ₉ F vernier within the ^- between the layers and is interposed a single layer YO ^+, Y ³⁺ ions are four O ^2- and three F ^- anion of (YO ₄ F ₃₎ and four O ^2- and four F ^- is coordinated by anionic it consists of (YO ₄ F _4).

Since there is fluorine (F) in the yttrium oxyfluoride (Y ₇ O ₆ F ₉ ) matrix, the difference in energy level is large, and thus near-ultraviolet rays having a larger energy than the visible light are required for excitation. Accordingly, the LED-use phosphor of the present invention can be excited by using near-ultraviolet rays.

Hereinafter, the present invention will be described in detail with reference to preferred embodiments thereof. However, the following examples are merely illustrative of the present invention, and the present invention is not limited to the following examples.

1. Phosphor Synthesis

Y ₂ O ₃ (Alfa 99.9%), CeO ₂ (Alfa 99.9%), Tb ₄ O ₇ (Alfa 99.9%) as starting materials were synthesized to synthesize Y _{7 (1-mn)} Ce _7m Tb _7n O ₆ F ₉ phosphors. ), And NH ₄ F (Alfa 99%) were prepared. The NH ₄ F may be provided in the form of a pellet to prevent it from being lost to ammonia and florine gas.

Various proportions of Y _{7 (1-mn)} Ce _7m Tb _{7n 6} F ₉ phosphors were formed by adjusting the proportions of the starting materials and quantitating and mixing to form a mixture. That is, various Y _{7 (1-mn)} Ce _7m Tb _{7n 6} F ₉ phosphors with _m ranging from 0 to 0.1 and n ranging from 0 to 0.15 were formed. For example, when m = 0 and n = 0, a Y ₇ O ₆ F ₉ phosphor is formed. When m = 0.1 and n = 0.15, a Y _5.25 Ce _0.7 Tb _1.05 O ₆ F ₉ phosphor is formed .

The mixture of the starting material was heated for two hours at 1050 ℃ under an atmosphere of 4% H ₂ and 96% Ar. The range of the atmosphere heating temperature and time is illustrative and may be, for example, an atmosphere of 2% to 6% H ₂ and 94% to 98% Ar, may be a temperature range of 1000 ° C to 1100 ° C, For 1 to 3 hours. By such heating, the mixture is calcined and crystallized. For example, in the case of calcination by heating at 850 ° C, the active agent (Tb ³⁺ ) may not be substituted into the matrix, and when calcined at 950 ° C, Y ₆ O ₅ F ₈ . Thus, when calcined by heating to a temperature in the range of 1000 ° C to 1100 ° C, the desired Y ₇ O ₆ F ₉ can be produced.

For reference, there is an existing study on the formation of Y ₇ O ₆ F ₉ : Eu vernier phase phosphor using NH ₄ F flux at high temperature. Thus, a flux assisted method was used to change the molar ratio of 1/2 Y ₂ O ₃ precursors and NH ₄ F flux at 1050 ° C. to provide a Y ₇ O ₆ F ₉ crystal structure. For example, the molar ratio of precursors (1/2 Y ₂ O ₃ + CeO ₂ + 1/4 Tb ₄ O ₇ ) to NH ₄ F flux can be quantified as 1: 2. In other words again, the Y ₂ O ₃ of Y ³⁺ ions, the CeO ₂ of Ce ³⁺ ion, and the Tb ₄ O ₇ for Tb ³⁺ molar number of the sum of an ion (hereinafter, Y ³⁺ + Ce ³⁺ + Tb ³⁺ ) and the number of moles of NH ₄ F flux is 1: 2. When the NH ₄ F flux concentration is lower than the above ratio, yttrium oxyfluoride having a stoichiometric composition can be synthesized. When the NH ₄ F flux is higher than the above ratio, Y ₇ O ₆ F _{9 is} not desired, YF ₃ may be formed together.

Further, when synthesizing a phosphor not containing Ce (i.e., Y _{7 (1-n)} Tb _7n O ₆ F ₉ phosphor), CeO ₂ (Alfa 99.9%) was excluded and quantified.

2. Method of measuring phosphor properties

X-ray diffractometer (Shimadzu XRD-6000 powder diffractometer, Cu-Ka radiation) was used to determine the crystal characteristics and phase of the synthesized LED phosphor (Y _{7 (1-mn)} Ce _7m Tb _7n O ₆ F ₉ ) -Ray diffraction pattern was measured.

For the calculation of the unit lattice of the LED-use phosphor, a unit lattice parameter measured using a Rietveld refinement program (Rietica) was set.

For fluorescence characteristics of the LED-use fluorescent substance, excitation and emission spectrum were measured at room temperature using a fluorescence spectrophotometer (Sinco Fluromate FS-2). The excitation and emission spectra were performed using Near-UV (NUV).

3. Characteristic Results of Phosphor

1 is a graph showing an X-ray diffraction pattern of a phosphor for LED according to an embodiment of the present invention.

In FIG. 1, the graphs (a) to (c) show, as a comparative example, graphs for Y ₂ O ₃ (ICSD 27772), YF ₃ (ICSD 26595), and Y ₇ O ₆ F ₉ (ICSD 68951) The calculated X-ray diffraction patterns are shown. (d) and (e) show Y _{7 (1-mn)} synthesized at 1050 ° C using a 1: 2 molar ratio of NH ₄ F flux to (Y ³⁺ , Ce ³⁺ , Tb ³⁺ ) ₎ Ce _7m Tb _7n O ₆ F ₉ X-ray diffraction patterns. (d) is a Y _5.95 Ce _0.35 Tb _0.7 O ₆ F ₉ phosphor in which m = 0.05 and n = 0.1, and (e) m = 0.1 and n = 0.15. Y _5.25 Ce _0.7 Tb _1.05 O ₆ F ₉ phosphor.

1, the phase of Y _{7 (1-mn)} Ce _7m Tb _7n O ₆ F ₉ (m = 0.01-0.1, n = 0-0.15) forms Y ³⁺ ions within the matrix of yttrium oxyfloride Ce < ^{3 +} > and Tb < ^{3 +} > ions, after being replaced by powder X-ray diffraction analysis.

Further, as shown in the graphs (d) and (e) of FIG. 1, when the molar ratio of NH ₄ F flux to (Y ³⁺ , Ce ³⁺ , Tb ³⁺ ) ions is doubled that is, 1: 2), Y ₂ O ₃ peaks corresponding to disappear, and Y ₂ O ₃ precursor is found to be completely reacted. In addition, the phosphor formed at the molar ratio clearly shows the Y ₇ O ₆ F ₉ vernier phase, while the YF ₃ structure was hardly observed. These results are consistent with previous studies on Eu ³⁺ doped Y ₇ O ₆ F ₉ phosphors.

2 is a graph showing excitation and emission spectrum of a phosphor for LED according to an embodiment of the present invention. FIG. 3 is a graph showing the relative light emission intensity according to the Tb ³⁺ ion content of the LED-use fluorescent material according to an embodiment of the present invention.

2 and 3, the phosphors for LEDs include compounds of Y _{7 (1-n)} Tb _7n O ₆ F ₉ (n = 0 to 0.15), for example Y _6.93 Tb _0.07 O ₆ F ₉ compound (n = 0.01), Y _6.65 Tb _0.35 O ₆ F ₉ compound (n = 0.05), Y _6.3 Tb _0.7 O ₆ F ₉ compound (n = 0.1), Y _5.95 Tb _1.05 O ₆ F ₉ compound .

Referring to FIG. 2, strong peaks appeared in the excitation range from 200 nm to 300 nm, which is analyzed to be related to the transition of Tb ³⁺ ions from 4f ⁸ to 4f ⁷ 5d ¹ . In addition, the peaks were observed in this region of 300 nm to 400 nm range, which is analyzed to be involved in transition to 4f 4f ^{8 8} from the Tb ³⁺ ion.

On the other hand, peaks appeared in the emission region in the range of 450 nm to 650 nm, particularly in the range of 530 nm to 550 nm, for example, Y ₇ O ₆ F ₉ doped with Tb ³⁺ ions at about 543 nm A strong green emission peak of the phosphor appeared. This emission peak is related to the transition of Tb ³⁺ ions from ⁵ D ₄ to ⁷ F ₅ . In addition, a peak related to the transition from ⁵ D ₄ to ⁷ F ₆ at 500 nm or less and a transition from ⁵ D ₄ to ⁷ F ₄ and a transition from ⁵ D ₄ to ⁷ F ₃ at above 550 nm (blue emission) Respectively.

As the molar concentrations of Tb ³⁺ ions were increased, the maximum intensity points of the emission peak were observed more prominently at approximately 543 nm. When the content of Tb ³⁺ ions in the Y _{7 (1-n)} Tb _{7n 6} F ₉ phosphor reaches n = 0.1 (~10 mol%), the relative luminescence intensity calculated by the integrated bladder is maximized.

Referring to FIG. 3, in the range where n is increased from 0 to 0.15, the maximum light emission intensity was exhibited at the content of Tb ³⁺ ions corresponding to n = 0.1. Further, in the region where n = 0.1 or more, the distance between the activator Tb ³⁺ ions becomes close to each other, so that non-radiation energy transfer such as exchange interaction between ions is marked and the emission intensity is reduced. This threshold value of Tb ³⁺ ion content is a characteristic characteristic in the Y ₇ O ₆ F ₉ matrix of the present invention.

The size of the unit cell of the LED phosphor was calculated as follows. The unit lattice of the Y ₇ O ₆ F ₉ (ICSD 68951) matrix is a = 5.423 (1) Å, b = 38.624 (6) Å, and c = 5.527 (1) Å. Y ₃ ⁺ ions (r = 0.96 Å, CN = 7 and r = 1.019 Å, CN = 8) in the Y ₇ O ₆ F ₉ structure with Tb ³⁺ ions (r = 0.98 Å, CN = 7 and r = 1.04 A unit cell of Y _{7 (1-n)} Tb _7n O ₆ F ₉ (n = 0.1) is slightly expanded. That is, a = 5.43158 (2) A, b = 38.77192 (2) A, c = 5.55434 (4) A. As the concentration of the Tb < ^{3 +} > ions is increased, the energy transfer is increased and the distance between the activators is reduced. Reduction of the emission intensity is due to non-radiative energy transfer between the activators from the result of the electrical interaction. The critical distance (R _c) is calculated using the formula below.

Where V is the volume of the unit cell, N is the number of possible dopant sites in the unit cell (N = 7), p _c is the critical concentration of the Tb ³⁺ ion, R _c is the energy transfer . When n = 0.1 in Y _{7 (1-n)} Tb _7n O ₆ F ₉ , V is 1169.7 Å ³ and R _c is 9.276 Å.

FIG. 4 is a graph showing excitation and emission spectrum of a phosphor for LED according to an embodiment of the present invention. FIG. 5 is a graph showing the relative emission intensity according to Ce ^{3 +} ion content of the LED-use fluorescent material according to an embodiment of the present invention.

4 and 5, the LED phosphors are Ce ³⁺ and Tb ³⁺ co-doped Y ₇ O ₆ F ₉ phosphors, and Y _{7 (1-mn)} Ce _7m Tb _7n O ₆ F ₉ (m = 0.1, n = 0 to 0.15, for example m is 0, 0.01, 0.05, 0.1 and n is 0, 0.01, 0.05, 0.1, 0.15. do.

The black dotted line graph on the lower side of FIG. 4 shows the excitation and emission spectrum of Y _6.65 Ce _0.35 O ₆ F ₉ phosphor in which m is 0.05 and n is 0. 4 shows the excitation and emission spectrum of Y _6.3 Tb _0.7 O ₆ F ₉ phosphor in which m is 0 and n is 0.1.

Referring to FIG. 4, as described above with reference to FIG. 2 and FIG. 3, when Ce is absent, a phosphor of 10% Tb ^{3 +} ion content (i.e., n = 0.1) is added to Y ₇ O ₆ F ₉ veneer mother liquor Maximum relative emission intensity. On the other hand, the Y ₇ O ₆ F ₉ phosphors doped with Ce ^{3 +} ions exhibit blue emission centered at about 382 nm without the Tb ^{3 +} ions (ie, n = 0), and at the 5d level of Ce ³⁺ Two important excitation peaks due to the Crystalline Field cleavage occurred around 310 nm and 330 nm.

If even a red solid line graph in the upper 4 is doped with the ion Ce ³⁺ and Tb ³⁺ ions co, m is 0.05, n is 0.1 Y _{5. 95} Ce _{0. 35} Tb _{0 . 7} O ₆ F ₉ phosphors. Under about 334 nm excitation, the broad band of the transition from f to d of Ce ^{3 +} ions in the phosphors was weak at about 382 nm, which is an effective energy transfer from Ce ³⁺ to Tb ³⁺ ions . Thus, the Y _5.95 Ce _0.35 Tb _0.7 O ₆ F ₉ phosphors exhibit significantly enhanced green emission peaks, which correspond to the ⁵ D ₄ to ⁷ F _J transitions of Tb ³⁺ ions. The green emission of the Y _5.95 Ce _0.35 Tb _0.7 O ₆ F ₉ phosphor under the 329 nm excitation is about 10 times that of the Y ₇ O ₆ F ₉ phosphor doped with Tb ³⁺ ions (i.e., Y _6.3 Tb _0.7 O ₆ F ₉ phosphor) Times more rapidly than that. As shown in FIG. 2, the broad excitation range of the Y ₇ O ₆ F ₉ phosphor doped with Tb ³⁺ ions (ie Y _6.3 Tb _0.7 O ₆ F ₉ phosphor) establishes a metastable energy level, Thereby increasing conversion characteristics due to strong Stark separation.

When the Tb ³⁺ ions are co-doped into Ce ³⁺ ions are doped matrix structure, it can generate a high-energy transition to a Tb ^{3 +} ions from the Ce ³⁺ ion. Energy transfer from such Ce ^{3 +} ions to Tb ^{3 +} ions is possible in a variety of hosts. The energy transfer process is explained by the non-radiative relaxation of the Ce ^{3 +} ions to the ⁵ D ₄ level, followed by the transition of the Td ^{3 +} ions from the 5d state to the ⁵ D ₃ level. That is, since the transition to the similar energy levels, Ce ³⁺ ion 5d level of the excited by F _J transitions of ² electrons to the transition to the ⁵ D ₃ levels of the Tb ³⁺ ion is this effective.

Referring to FIG. 5, the relative intensity of Y _{7 (1-mn)} Ce _7m Tb _7n O ₆ F ₉ (m = 0.01, 0.05, 0.1, n = 0.01-0.15) is shown. Similarly to the phosphors described with reference to FIGS. 2 and 3, the emission intensity of the phosphor was increased with increasing the Tb ^{3 +} content from n = 0.01 to n = 0.15 with respect to the Ce ^{3 +} content corresponding to m = 0.01, Showed no critical phenomenon. On the other hand, when the value of m is increased to 0.05 or 0.1 (i.e., the Ce ³⁺ content is increased), Y _{7 (1-mn)} Ce _7m Tb _7n O ₆ F ₉ (m = 0.05, 0.1, n = 0.01 -0.15) showed a critical phenomenon in which the phosphor exhibited the maximum Tb ³⁺ green emission at a Tb ³⁺ content of n = 0.1. It can be seen that the relative intensity of the green emission (I _{542 nm} ) increases with increasing Tb ³⁺ content in the phosphor. As the m value increases for the same n value, the emission intensity tends to decrease, which is analyzed as a quenching phenomenon with increasing Ce ³⁺ content.

With respect to the Ce ³⁺ concentration, when m is less than 0.01, the Ce ³⁺ concentration is low and the luminescence intensity is lowered. When m = 0.15, the luminescence intensity is lowered due to the quenching phenomenon. With respect to the concentration of Tb ^{3+, if the} concentration of Tb ³⁺ is less than 0.01, the concentration of Tb ³⁺ is low and the luminescence intensity is lowered. When n = 0.15, the luminescence intensity is lowered according to the extinction phenomenon. .

For reference, the present inventors have found that when Ce ³⁺ is substituted, the maximum green intensity appears at m = 0.05. However, when Ce ^{3 +} and Tb ^{3 +} are co-substituted as in the present invention, the maximum green intensity appears at m = 0.01.

FIG. 6 is a graph showing the emission spectrum of a phosphor for LED according to an embodiment of the present invention. 7 is a graph showing the emission spectrum of the LED-use phosphor according to an embodiment of the present invention. Figure 6 _{Y 7 (1-mn) Ce} 7m Tb 7n O 6 F 9 (m = 0.01, n = 0.01-0.15) in the case of the phosphor, Fig. 7 _{Y 7 (1-mn) Ce} 7m Tb 7n O 6 F ₉ (m = 0.05, n = 0.01-0.15) phosphors.

6 and 7, the energy transfer from the Ce ³⁺ ion to the Tb ³⁺ ion is controlled by the emission of Y _{7 (1-mn)} Ce _7m Tb _7n O ₆ F ₉ (m = 0.01, n = 0-0.15) Once generated by the Ce ^{3 +} absorption in the spectrum, _{however, Y 7 (1-m)} Ce 7m O 6 F 9 (m = 0.05) 1% Tb 3 + is substituted in the phosphor, absorption of the Ce ³⁺ ions of energy transfer Decrease rapidly. Thus, the Ce ³⁺ ion acts as a sensitizer and the Tb ³⁺ ion acts as an activator.

8 is a graph showing the energy transfer efficiency according to the Tb ³⁺ ion content of the LED phosphor according to an embodiment of the present invention. FIG. 8 shows a case of Y _{7 (1-mn)} Ce _7m Tb _7n O ₆ F ₉ (m = 0.01, n = 0.01-0.15) phosphors.

8, the energy transfer efficiency between Ce ^{3 +} and Tb ^{3 +} ions in Y _{7 (1-mn)} Ce _7m Tb _7n O ₆ F ₉ (m = 0.01, n = 0-0.15) η _T ) was calculated using the following equation (2).

In the above formula (2), I _S represents the light emission intensity of the sensitizer when the active agent is present (i.e., the Ce ³⁺ ion and the Tb ³⁺ ion are co-doped), I _SO represents the sensitizer (I.e., only Ce ³⁺ ions are doped). In the case of I _S = I _SO , even if a sensitizer is added, the luminescence intensity is constant and eta _T approaches 0 and the efficiency is low. On the other hand, in the case of I _S >> I _SO , the addition of a sensitizer greatly increases the emission intensity, and η _T approaches 1 and the efficiency is high.

_{Y 7 (1-mn) Ce} 7m Tb 7n O 6 F 9 (m = 0.01) as Tb ^{3 +} content of the n = increased from 0.01 to 0.05 in the fluorescent substance, the efficiency is about 0.2 (i.e., 20%) 0.8 from (I.e., 80%). Then, when the Tb ³⁺ content in the phosphor was increased to n = 0.1, the energy transfer efficiency reached about 0.85 (i.e., 85%). When the Tb ³⁺ content in the phosphor increased to n = 0.15, the efficiency of energy transfer to the Tb ³⁺ ions was further increased, maximizing to about 0.9 (ie, 90%). When the Ce ³⁺ concentration is m = 0.01 and the energy transfer efficiency is 0.5, the total concentration of Ce ³⁺ and Tb ³⁺ ions is lower than 0.05. The energy transfer between the Ce ³⁺ and Tb ³⁺ ions, which show this energy efficiency change, is analyzed to be due to the electric multipole interaction.

9 to 11 are graphs illustrating the energy transfer mechanism of the LED phosphor according to an embodiment of the present invention. 9 to 11 show the case of Y _{7 (1-mn)} Ce _7m Tb _7n O ₆ F ₉ (m = 0.01, n = 0.01-0.15) phosphors.

Referring to Figures 9-11, the energy transfer mechanism is represented by a linear graph of C _Tb ^{? / 3} for I _SO / I _S , according to the Dexter theory. Here, C _Tb represents the concentration of Tb ³⁺ ions. a = 3, 6, or 8, which correspond to exchange, dipole-dipole interaction, or dipole-quadrupole interaction, respectively. The relationship between the concentration of ions and the intensity of light emission can be used to determine which interaction plays a major role.

9, a case of α = 3 (that is, in the case of exchange Im), a line graph is _{Y 7 (1-mn) Ce} 7m Tb 7n O 6 F 9 phosphors ^{(R 2 = 0.972, m =} 0.01) &^{Lt; /} RTI > of Ce ³⁺ ions to Tb ³⁺ ions. If the Referring to Figure 10, α = 6 (that is, dipole-For dipole interactions Im), a line graph is _{Y 7 (1-mn) Ce} 7m Tb 7n O 6 F 9 phosphors (R ² = 0.9932, m = 0.01) energy transition from Ce ³⁺ ions to Tb ³⁺ ions. If the Referring to Figure 11, α = 8 (that is, dipole-For quadrupole interaction Im) linear graph _{Y 7 (1-mn) Ce} 7m Tb 7n O 6 F 9 phosphors (R ² = 0.9671, m = 0.01) energy transition from Ce ³⁺ ions to Tb ³⁺ ions. From the results of FIGS. 9 to 11, it can be seen that the dipole-dipole interaction, in which the fitting of the data and the linear graph is most optimized, involves a dominant energy transfer mechanism. It should be noted, however, that this does not preclude the existence of other interactions as described above as the energy transfer mechanism.

12 is a graph showing the excitation and emission spectrum of a phosphor for LED according to an embodiment of the present invention. In FIG. 12, A is a case of Y _{7 (1-mn)} Ce _7m Tb _7n O ₆ F ₉ (m = 0.01, n = 0.15) phosphor according to an embodiment of the present invention, B is a case of a typical green phosphor to be.

Referring to FIG. 12, in the case where a Ce ³⁺ ion as a sensitizer and a Tb ³⁺ ion as an activator are present in a Y ₇ O ₆ F ₉ matrix lattice according to an embodiment of the present invention, Light was observed. Y _{7 (1-mn)} Ce _7p Tb _7n O ₆ F ₉ (m = 0.01, n = 0.15) phosphor of the embodiment of the present invention is excited at 334 nm and has a center at 542 nm, Tb ^{3 +} Green emission and the strongest green emission at 542 nm. On the other hand, a conventional phosphor (B) excites at 421 nm and exhibits green light centered at 518 nm, and the strongest green emission at 450 and 650 nm appears at 421 nm. The chromaticity coordinates x and y according to the CIE values of yttrium oxyfluoride were x = 0.297 and y = 0.591 in the case of the phosphor (A) of the embodiment of the present invention, and the typical green phosphor (B) 0.230 and y = 0.639. The figure inserted in FIG. 12 shows the green emission of the phosphor (A) of the present invention and the conventional green phosphor (B) at 254 nm, 312 nm, and 365 nm.

4. Conclusion

A single phase of a Y ₇ O ₆ F ₉ vernier phosphor co-doped with Ce ³⁺ and Tb ³⁺ ions was prepared through a flux-assisted solid phase reaction using NH ₄ F flux in a reducing atmosphere at 1050 ° C. The formed phosphor was composed of Y _{7 (1-mn)} Ce _7m Tb _7n O ₆ F ₉ (m = 0.01-0.1, n = 0-0.15).

X-ray diffraction patterns of the formed phosphor were examined to index peak positions. The photoluminescence (PL) excitation and emission spectra of the Tb ^{3+ -activated} yttrium-oxyfluoride phosphors are clearly shown with critical emission quenching as a function of Tb ³⁺ content in Y _{7 (1-n)} Tb _7n O ₆ F ₉ Respectively. Y ₇ O ₆ F ₉ By doping Tb ³⁺ in the matrix lattice, effective green emission was achieved and Y _{7 (1-n)} Tb _7n O ₆ F ₉ (n = 0.01 ₎ at Tb ^{3 +} -0.15) phosphor was obtained.

Significantly enhanced green emission was observed in the PL spectrum under near-ultraviolet (NUV) excitation after doping the Y ₃ O ₆ F ₉ structure with Ce ³⁺ and Tb ³⁺ activators. The emission of Tb ³⁺ transitions in the vernier matrix lattice was increased about 10-fold by co-doping Ce ³⁺ sensitizer through strong energy transfer from Ce ³⁺ to Tb ³⁺ . It was also found that the luminescence intensities of the host lattices depend on the co-doped Ce ³⁺ content (m = 0.01, 0.05) and the Tb ³⁺ content (n = 0, 0.01, 0.05, 0.1, 0.15).

Y _{7 (1-mn)} Ce _7m Tb _7n O ₆ F _{9 When} the Ce ³⁺ content in the phosphor was m = 0.01, 0.05 and 0.1, a significant quenching of the relative intensity occurred at a Tb ³⁺ content of n = 0.1 . C _Tb ^{α / 3} by a line graph of the I _S / I _SO α = 6 this has been determined, Y ₇ O ₆ F energy transfer to Tb ³⁺ from Ce ³⁺ in the phosphor _9, for the Ce ³⁺ is a dipole-dipole It was identified as a mechanism of interaction. Co-doping of Ce ³⁺ ions and Tb ³⁺ ions in a single-phase Y ₇ O ₆ F ₉ structure can achieve strong green emission and be effective for the requirements of near-ultraviolet LEDs.

The phosphor for LED according to the technical idea of the present invention is a phosphor in which Ce ³⁺ (sensitizer) and Tb ³⁺ (activator) are doped in the non-stoichiometric yttrium oxyfluoride (Y ₇ O ₆ F ₉ ) ≪ / RTI > Unlike the conventional phosphors, the emission intensity of green is significantly increased by the energy transfer from Ce ³⁺ ions to Tb ³⁺ ions.

The phosphor according to the technical idea of the present invention may be used alone as a green phosphor, in RGB combination, or in various LEDs for white LEDs. In particular, the phosphors can be used for LEDs excited by near ultraviolet rays.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention as defined in the appended claims. Will be apparent to those of ordinary skill in the art.

Claims (15)

Yttrium oxy-fluoride (Y ₇ O ₆ F ₉₎ matrix Ce ^{3 +} and Tb ^{3 +} is co-doped configured, LED fluorescent substance for a. The method according to claim 1,
Wherein the phosphor comprises a compound represented by the following formula (1).
[Chemical Formula 1]
Y _{7 (1-mn)} Ce _7m Tb _7n O ₆ F ₉
(M = 0 to 0.1, n = 0 to 0.15 in the above formula (1) 3. The method of claim 2,
Wherein the phosphor is excited by near ultraviolet rays. 3. The method of claim 2,
^Wherein the phosphor emits light by energy transfer from the Ce ³⁺ to the Tb ³⁺ . 3. The method of claim 2,
Wherein the phosphor exhibits a maximum green light emission intensity at m = 0.01 and n = 0.15. 3. The method of claim 2,
Wherein the phosphor exhibits a maximum green light emission intensity at n = 0.1 when m = 0.05. 3. The method of claim 2,
Wherein the phosphor exhibits a maximum green light emission intensity at n = 0.1 when m = 0.1. The method according to claim 1,
Wherein the phosphor has a dipole-dipole interaction as a dominant energy transfer mechanism. The method according to claim 1,
Wherein the matrix comprises a Y ₇ O ₆ F ₉ vernier phase. Yttrium oxy-fluoride (Y ₇ O ₆ F ₉₎ matrix is Tb ³⁺ doped in,, LED phosphor comprising a compound of formula 2 below.
(2)
Y _{7 (1-n)} Tb _7n O ₆ F ₉
(N = 0 to 0.15 in the above formula (2) 11. The method of claim 10,
^Wherein the phosphor emits green by transition of Tb ³⁺ from ⁵ D ₄ to ⁷ F ₅ . A method of producing a phosphor for LED of the following formula (1)
Quantitating and mixing the starting materials of Y ₂ O ₃ , CeO ₂ , Tb ₄ O ₇ , and NH ₄ F flux to form a mixture; And
And calcining the mixed material to crystallize the phosphor for LED.
[Chemical Formula 1]
Y _{7 (1-mn)} Ce _7m Tb _7n O ₆ F ₉
(M = 0 to 0.1, n = 0 to 0.15 in the above formula (1) 13. The method of claim 12,
Wherein the NH ₄ F flux is provided in the form of a pellet to prevent loss of ammonia and flourine gas. 13. The method of claim 12,
The crystallization step is under 2% to 6% H ₂ and 94 to an atmosphere of 98% Ar, at a temperature ranging from 1000 to 1100 ℃ ℃, method for producing a fluorescent substance for LED, is carried out for 1 hour to 3 hours. 13. The method of claim 12,
The ratio of the molar number of Y ₃ ⁺ ions of Y ₂ O ₃ , Ce ^{3 +} ions of CeO ₂ , and Tb ³⁺ ions of Tb ₄ O ₇ to the molar number of NH ₄ F is 1: 2 Wherein the phosphor is a phosphor.

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