JP4550608B2 - Fluorescent complex and lighting device - Google Patents

Description

  The present invention relates to a fluorescent complex having a high luminous intensity and a long lifetime and an illumination device.

  In recent years, the luminous intensity and lifetime of light-emitting elements, such as LED elements, have been remarkably improved, and a wide variety of markets are being developed mainly for lighting applications.

  LED elements using inorganic phosphors, which are currently mainstream, are dramatically improving in luminous efficiency. In particular, white LEDs are said to surpass the luminous efficiency of fluorescent lamps in the future. However, when an LED is used in a lighting device, there are many applications that require not only luminous efficiency but also excellent color rendering, and an LED using only an inorganic phosphor cannot satisfy all of these characteristics. is the current situation.

  The use of organic phosphors for LEDs is already known (see, for example, Patent Document 1). However, LEDs using organic phosphors as light emitters have not yet been put to practical use for illumination due to the following problems.

  1) In particular, when a near-ultraviolet LED, which is now becoming the mainstream, is used as a light source, and an organic phosphor is used for an LED using an R, G, B illuminant, the organic compound is generally weak against ultraviolet rays. Is remarkable. In particular, when there is absorption based on the n-π * transition in the near-ultraviolet region, the deterioration is rapid.

  2) The fluorescence spectrum of the organic phosphor may change depending on the concentration, and it is difficult to control the spectrum. Further, the fluorescence intensity is also concentration dependent, and concentration quenching occurs in a high concentration region.

  3) The fluorescence spectrum changes depending on the type of polymer matrix in which the organic phosphor is dispersed.

  On the other hand, a phosphor made of a rare earth complex has the following advantages compared to a normal organic phosphor.

  1) The emission wavelength is unique to rare earths and is not affected by the dye concentration and the type of polymer matrix dispersed, and the fluorescence spectrum is stable.

  2) The ligand of the rare earth complex is an organic compound. However, when the ligand absorbs light and enters the excited state, it returns to the ground state by energy transfer to the central element, so that an irreversible chemical change from the excited state occurs. The chance to wake up decreases. Therefore, durability against ultraviolet rays can be expected.

  However, the rare earth fluorescent complex is required to have a longer lifetime and a higher luminous intensity in order to be used in general lighting applications.

  A characteristic that greatly affects the durability of the rare earth fluorescent complex is the stability of the ligand itself with respect to the photochemical reaction. Since phosphors irradiated with light are exposed to high heat and strong light, radical (oxidation) degradation is likely to proceed. When the ligand undergoes a chemical change, the coordination ability is reduced and the ligand is detached, so that the fluorescence intensity may be deteriorated or the changed ligand may be deactivated.

Moreover, in order to implement | achieve the high luminous intensity of a rare earth fluorescent complex, the solubility with respect to the polymer matrix of a rare earth fluorescent complex is requested | required. When the solubility is low and the phosphor is present in the form of particles in the polymer matrix, sufficient light intensity cannot be obtained due to light scattering.
JP 2004-262909 A

  The present invention has been made under the above circumstances, and an object thereof is to provide a fluorescent complex and a lighting device having high luminous intensity and long life.

  As a result of intensive studies on the above problems, the present inventors have realized high luminous intensity and high durability when using a fluorescent complex into which a specific ligand containing a substituent having an optical center is introduced. As a result, the present invention has been accomplished.

  That is, one embodiment of the present invention has a β diketone as a ligand, and a hydrogen atom in a methylene site at a position sandwiched between two carbonyl groups of the β diketone includes at least one hydrogen atom and has an optical center. Provided is a fluorescent complex which is substituted with a substituent.

  Another embodiment of the present invention provides a lighting device including a light-emitting element and a fluorescent layer that is provided on a light-emitting surface side of the light-emitting element and includes the above-described fluorescent complex. Here, the light emitting element emits light having a wavelength (wavelength from ultraviolet light to blue visible light) that excites the fluorescent complex of the present invention to emit light. For example, a semiconductor such as a light emitting diode or a laser diode. An example is a light emitting element.

  As such a fluorescent complex, at least one selected from the group consisting of a europium complex, a terbium complex, an iridium complex, and an erbium complex can be used.

  In this case, the ligand of the fluorescent complex can be a combination of β diketone and phosphine oxide.

As a fluorescent complex having a β diketone as a ligand and a hydrogen atom of a methylene moiety at a position sandwiched between two carbonyl groups of the β diketone being substituted with a substituent having an optical center, the following formula ( Those having the structure represented by 1) can be used.

(In the formula, R _{1 to} R ₉ are each composed of an alkyl group or an alkoxy group having a straight chain or branched structure having 20 or less carbon atoms, a phenyl group, a biphenyl group, a naphthyl group, a heterocyclic group, and a substituent thereof. (X is a hydrogen atom or deuterium atom, Ar is an aromatic moiety containing a substituent, and M is a central metal ion.)
In this case, in the formula (1), R ₈ can be an aliphatic alkyl group. In formula (1), it is desirable that the phosphine oxide is asymmetric, that is, the combination of R _{1 to} R _{3 and} the combination of R _{4 to} R ₆ are not the same. It is also desirable that the β diketone is asymmetric, that is, R ₇ and R ₉ are not the same.

Moreover, what has a structure represented by following formula (2) can be used as a fluorescent complex.

(In the formula, R ^{1 to} R ⁷ are composed of an alkyl group or an alkoxy group having a straight chain or branched structure having 20 or less carbon atoms, a phenyl group, a biphenyl group, a naphthyl group, a heterocyclic group, and a substituent thereof. X is a hydrogen atom or deuterium atom, Ar is an aromatic (aromatic) moiety containing a substituent, M is a central metal ion, m is 1 or 2, and n is an integer of 1 or more .) Here, n is preferably an integer of 2 or more, and it is possible to increase the degree of freedom of the ligand and improve the coordination ability.

In this case, in the formula (2), R ⁶ can be an aliphatic alkyl group. In the formula (2), it is desirable that the phosphine oxide is asymmetric, that is, the combination of R ¹ and R ² is not the same as the combination of R ³ and R ⁴ . It is also desirable that the β diketone is asymmetric, that is, R ⁵ and R ⁷ are not the same.

Furthermore, what has a structure represented by following formula (3) can be used as a fluorescent complex.

(In the formula, R _{1 to} R ₉ are composed of an alkyl group or an alkoxy group having a straight chain or branched structure having 20 or less carbon atoms, a phenyl group, a biphenyl group, a naphthyl group, a heterocyclic group, and a substituent thereof. R ₁₀ is selected from the group, R ₁₀ is an alkyl group having a branched structure containing at least one hydrogen atom and having 20 or less carbon atoms, X is a hydrogen atom or deuterium atom, and M is a central metal ion.)
In this case, in Formula (3), it is desirable that the phosphine oxide skeleton is asymmetric, that is, the combination of R _{1 to} R _{3 and} the combination of R _{4 to} R ₆ are not the same. It is also desirable that the β diketone is asymmetric, that is, R ₇ and R ₉ are not the same.

Furthermore, what has a structure represented by following formula (4) can be used as a fluorescent complex.

(In the formula, R ^{1 to} R ⁷ are composed of an alkyl group or an alkoxy group having a straight chain or branched structure having 20 or less carbon atoms, a phenyl group, a biphenyl group, a naphthyl group, a heterocyclic group, and a substituent thereof. R ⁸ is selected from the group, R ⁸ is an alkyl group having a branched structure containing at least one hydrogen atom and having 20 or less carbon atoms, X is a hydrogen atom or deuterium atom, M is a central metal ion, m is 1 or 2 , N is an integer of 1 or more.) Here, n is preferably an integer of 2 or more, and it is possible to increase the degree of freedom of the ligand and improve the coordination ability.

In this case, in the formula (4), it is desirable that the phosphine oxide skeleton is asymmetric, that is, the combination of R ¹ and R ² is not the same as the combination of R ³ and R ⁴ . It is also desirable that the β diketone is asymmetric, that is, R ⁵ and R ⁷ are not the same.

  Hereinafter, the reason why the rare earth complex having the structure represented by the above formulas (1) to (4) is excellent in luminous intensity and lifetime will be described.

  As described above, the deterioration factor of the fluorescent complex is light (thermal) oxidation deterioration, and this deterioration is considered to proceed radically. As a result of investigating the relationship between the structure and lifetime of β-diketone in a conventional rare earth complex having a structure represented by the following formulas (10) to (13), the present inventors have found that the following order is obtained.

Formula (10) >> Formula (11) >> Formula (12) >> Formula (13)

  However, the above order is for the lighting device having the structure shown in FIG. 1, and the emission center wavelength of the light emitting element is 402 nm, and is the result in the case of 20 mA, 3.7 V drive.

  From the comparison of the light intensity half lives of the above formulas (10), (11), (12), and (13), the correlation between the lifetime and the structure of β-diketone was clarified. That is, in a photochemical degradation reaction, a methylene moiety sandwiched between two carbonyl groups of a β-diketone undergoes radical cleavage, and oxygen reacts there to undergo oxidative degradation. The ease with which radical cleavage occurs depends largely on the stability of the radical species after cleavage. The stability of β-diketone radicals is highly dependent on two substituents. From the point of conjugation, the more aromatic substituents, the more stable and further stabilized with a heterocycle.

  Accordingly, the stability of the generated radical species is in the following order.

Aliphatic substituent> benzene ring>> heterocycle (thiophene ring)
The order of the lifetime of the rare earth complex and the order of stability of the radical species are the results strongly suggesting the radical reaction of the β-diketone.

  Therefore, the technique for improving the lifetime of the rare earth complex is as follows.

  A) In order to destabilize the radical species of β-diketone, the substituent is composed solely of an aliphatic group.

  B) The methylene moiety located between the two carbonyl groups of the β diketone is substituted with another alkyl group.

  However, with the method A) alone, it is difficult to achieve the lifetime of the lighting device using a light emitting element such as an LED element that can be used for general lighting applications. The solubility of the functional complex in the matrix is reduced. When the solubility decreases, the fluorescent complex crystallizes in the polymer matrix, and the light intensity decreases due to light scattering.

  From the above results, it can be seen that it is important to perform alkyl group substitution of B) and maintain solubility in the resin in order to achieve both high luminous intensity and long life of the lighting device.

As a result of intensive studies based on these findings, the present inventors have found that the above problem can be solved by introducing a substituent as shown in the following formula (14), and the present invention has been achieved. It was.

(In the formula, R _{7 to} R ₉ are composed of an alkyl group or an alkoxy group having a straight chain or branched structure having 20 or less carbon atoms, a phenyl group, a biphenyl group, a naphthyl group, a heterocyclic group, and a substituent thereof. Selected from the group, X is a hydrogen atom or deuterium atom, Ar is an aromatic moiety, and a broken line is a coordination bond.)
In the ligand of the above formula (14), the active methylene moiety of the β-diketone is substituted, so that the photochemical degradation hardly proceeds. Moreover, since the substituent which substitutes the hydrogen atom of a methylene site is a structure which has an optical center, and is asymmetric, crystallization of a complex is inhibited greatly. Furthermore, when the substituents on both sides of the β-diketone have different structures, the β-diketone has at least two optical centers, so that it becomes a mixture of diastereoisomers, and the crystallization of the complex is further inhibited.

R ₇ and R ₉ in the above formula (14) are more preferably not aromatic groups such as aliphatic alkyl groups. Although the effect is somewhat reduced, it is also possible to use an alkyl group having 20 or less carbon atoms having a branched structure containing at least one hydrogen, instead of Ar in the formula (14).

  On the other hand, β-diketone has a cis form and a trans form. The cis form coordinates well with rare earth metal ions such as europium ions because the two ketones have the same orientation, but the trans form coordinates with rare earth metal ions such as europium ions because the two ketones have different orientations. It becomes difficult to do. The stability of the cis- and trans-isomers greatly depends on the type and combination of substituents for the β-diketone.

The present inventor investigated β diketones that are cis bodies and stably coordinate to rare earth metal ions such as europium ions. As a result, when a ligand having a structure represented by the following formulas (7), (8), and (9) is used, the stability of the cis form of β-diketone is increased and the coordination ability to rare earth ions is increased. Thus, it was found that durability against light and heat can be improved.

(Wherein R ¹¹ and R ¹² are each an alkyl group, a fluoroalkyl group, a perfluoroalkyl group, or an alkoxy group having a straight chain or branched structure having 20 or less carbon atoms, a phenyl group, a biphenyl group, a naphthyl group, R ¹³ and R ¹⁴ are selected from the group consisting of a heterocyclic group and a substituent thereof, and R ¹³ and R ¹⁴ are each an alkyl group, a fluoroalkyl group, a perfluoroalkyl group having a straight chain or branched structure having 20 or less carbon atoms, or R ¹⁴ is selected from the group consisting of an alkoxy group, a phenyl group, a biphenyl group, a naphthyl group, a heterocyclic group, and a substituent thereof, and a halogen atom and a hydrogen atom, and R ¹⁴ is the same or different up to 5 types of substituents, X is a hydrogen atom or a deuterium atom, and m is an integer of 5 or less.)

(Wherein R ²¹ and R ²² are each an alkyl group, a fluoroalkyl group, a perfluoroalkyl group, or an alkoxy group having a straight chain or branched structure having 20 or less carbon atoms, a phenyl group, a biphenyl group, a naphthyl group, R ²³ -R ²⁸ is selected from the group consisting of a heterocyclic group and a substituent thereof, R ²³ -R ²⁸ is an alkyl group, a fluoroalkyl group, a perfluoroalkyl group having a straight chain or branched structure having 20 or less carbon atoms, or R ²⁸ is selected from the group consisting of an alkoxy group, a phenyl group, a biphenyl group, a naphthyl group, a heterocyclic group, and substituents thereof, and a halogen atom and a hydrogen atom, and R ²⁸ is the same or different up to four types of substituents. M is an integer of 4 or less.)

(In the formula, R ³¹ and R ³² are each an alkyl group, a fluoroalkyl group, a perfluoroalkyl group, or an alkoxy group having a straight chain or branched structure having 20 or less carbon atoms, a phenyl group, a biphenyl group, a naphthyl group, R ³³ is selected from the group consisting of a heterocyclic group and a substituent thereof, and R ³³ is an alkyl group, a fluoroalkyl group, a perfluoroalkyl group, or an alkoxy group having a straight chain or branched structure having 20 or less carbon atoms, (Selected from the group consisting of a phenyl group, a biphenyl group, a naphthyl group, a heterocyclic group, and a substituted form thereof, and a halogen atom and a hydrogen atom. Ad is an adamantyl group or a substituted form thereof.)
R ¹⁴ in the formula (7) and R ²⁸ in the formula (8) are preferably bonded to the para position with respect to the position where the carbon atom serving as the optical center is bonded to the benzene ring. In this case, the coordinating ability is particularly large, and it is possible to have excellent durability against light and heat.

  According to the present invention, it is possible to achieve both the fluorescence intensity and the lifetime of the fluorescent complex, and it is possible to realize an illumination device that is excellent in luminous intensity and lifetime.

  The best mode for carrying out the invention will be described below.

  As shown in FIG. 1, the lighting device according to an embodiment of the present invention has a structure in which a light emitting layer 3 is arranged on a light emitting element 2 accommodated in a plastic cell 1. The light emitting layer 3 is obtained by dispersing phosphor particles 5 in a polymer matrix 4. As the light emitting element 2, for example, an LED chip that emits light having a wavelength from ultraviolet rays to blue visible light can be used. The LED chip 2 is made of, for example, a GaN-based semiconductor material, and is provided with a pair of electrodes (not shown). The light emitting element 2 is not limited to an LED chip, and for example, a light emitting device such as a laser diode that emits light of the same wavelength can be used.

  The phosphor particle 5 is a fluorescent complex having a β-diketone as a ligand.

In this embodiment, the ligand composed of β-diketone can be synthesized according to the reaction formula represented by the following formula (15).

That is, R ³ Li (R ³ is an alkyl group or aromatic group) that is an organolithium reagent is allowed to act on β-diketone A in a solvent such as tetrahydrofuran or ether. A dehydrated solvent is used. For example, n-butyl lithium, t-butyl lithium, methyl lithium, phenyl lithium and the like are desirable. In order to prevent side reactions and allow the first stage proton abstraction reaction to proceed efficiently, the reaction temperature is preferably as low as about -78 ° C. When the reaction state is confirmed by NMR (nuclear magnetic resonance) measurement under nitrogen gas purge, TLC, etc., and the reaction rate is low at −78 ° C., it is desirable to raise the reaction temperature little by little. In order to further increase the rate of H abstraction reaction and improve the yield, it is more desirable to add additives such as LDA (lithium diisopropylamide) and TMEDA (N, N, N, N-tetramethylethylenediamine).

Thereafter, when iodide R ⁴ I (R ⁴ is an alkyl group having an optical center) is added, β-diketone B to which substituent R ⁴ is added is obtained. As a method for purifying the compound, HPLC (high performance liquid chromatography), PTLC (preparative thin film chromatography), recrystallization method and the like are desirable, and the structure of the compound can be determined by NMR.

Further, as disclosed in J. Am. Chem. Soc., 126, 6884 (2004), a cation prepared from gold chloride and a silver salt (AgOTf (Tf is trifluoromethanesulfonyl)) using dichloromethane as a reaction solvent. There is a method of introducing a substituent having an optical center into an active methylene site of a β-diketone by using an addition reaction of the active methylene site of the β-diketone to a styrene derivative with a functional gold catalyst. In order to synthesize with a high yield through this reaction route, in the above formula (14), R ₈ is more preferably an aliphatic (aliphatic). In this case, the cis isomer is generally dominant, and the coordination ability to rare earth metal ions such as europium ions is increased.

In addition, when R ₇ and R ₉ are unsubstituted phenyl groups, the ratio of the trans isomer increases, so the coordination ability moves in a weak direction.

A method in which R ⁴ is a perfluoroalkyl group is also conceivable. This is intended to suppress vibrational deactivation due to C—H bonds and obtain a higher fluorescence intensity. However, when a perfluoroalkyl group is introduced, the mobility of the substituent itself is poor, and the hydrophobicity of the compound is greatly increased, resulting in a decrease in solubility in resins and solvents. Even if a branched structure is introduced, the solubility is not improved.

In this embodiment, R ⁴ is a substituent having an aromatic moiety or an alkyl group having a branched structure containing at least one hydrogen atom. Since these are substituents having excellent mobility, solubility and dispersibility are improved by introducing an optical center by constructing an aromatic site or a branched structure.

  Here, the stability of β diketone, which is a ligand of the europium complex in the present embodiment, will be described.

  The stability of the europium complex depends greatly on the structure of the ligand. In general, β-diketone is activated at the methylene site between the ketones due to the influence of the ketone, and the acidity is generally increased. When β-diketone becomes active, radicals are generated by photochemical reaction, and the structure of the ligand is changed by subsequent oxidation reaction. As a result, β-diketone is liberated from europium ions, resulting in a weak fluorescence intensity.

  The activity of the methylene moiety greatly depends on the structure of the substituent of β diketone. When the stability of radical species generated from β-diketone generated when H is radically cleaved at the methylene site is high, the equilibrium shifts to the radical-generating side, so the proportion of radical species generated from β-diketone increases and deterioration occurs. Is promoted.

  On the other hand, when the stability of the radical species generated from the β diketone is small, the equilibrium shifts to a non-radical generation system, so the ratio of the radical species generated from the β diketone is reduced and the degradation reaction is suppressed.

  The stability of radical species generated from β-diketone depends greatly on the substituent of β-diketone. When the substituent is aromatic, the conjugation range of the radical is expanded, so that the radical is stabilized, and in the case of ariphatic, it is unstable.

From these findings, the present inventors have found that there is a correlation represented by the following formula (16) with respect to the substituent of the β diketone and the lifetime of the europium complex.

  The order shown in the above equation (16) is a result that almost fits the above discussion.

  Therefore, in order to extend the lifetime of the europium complex, it is necessary to use a ligand that does not have an active methylene site, or to use a ligand that does not lose the coordination ability to the europium ion even when reacted. An effective method is to replace H at the methylene moiety with a substituent.

  However, the present inventors have found that the solubility and dispersibility of the europium complex in the polymer matrix are reduced when H in the methylene moiety is replaced with a substituent. The present inventors have found that in order to avoid such a decrease in solubility and dispersibility, it is effective to realize asymmetry of the molecular structure by introducing an optical center into the substituent. The present invention has been achieved.

  Hereinafter, examples of the present invention will be shown, and the present invention will be described more specifically.

Example 1
The molecular design of the complex having the structure represented by the following formula (17) was performed. The β-diketone ligand of this complex can be synthesized by the synthesis method of formula (15) described above. Further, it is desirable to use the method of the following formula (18). The reaction solvent is dichloromethane, and the catalyst is a cationic gold catalyst prepared from 5 mol% of gold chloride and 15 mol% of silver salt ((AgOTf (Tf is trifluoromethanesulfonyl))). An olefin (such as styrene) is slowly dropped into the β-diketone solution over several hours. The molar ratio of β-diketone to olefin is preferably 1: 1.5. The reaction temperature is room temperature, and when it is urgent, it is refluxed.

  The β-diketone obtained as described above is coordinated to a europium ion and subsequently coexisted with triphenylphosphine oxide and trioctylphosphine oxide, whereby a europium complex of the formula (17) is obtained. The europium complex is dispersed in a fluorine-based polymer (cefural: trade name, manufactured by Central Glass Co., Ltd.) to form the light-emitting layer (phosphor layer) 3 in FIG. 1 to manufacture a light-emitting element.

The complex having the structure represented by the following formula (17) is excellent in solubility in a fluorine-based polymer due to its strong amorphous property, and can also be excellent in durability against light and heat as described above. .

  In addition, a halogen atom (for example, a chlorine atom) may be introduced into the benzene ring as in the formula (17), thereby increasing the stability of the cis form of β-diketone and improving its coordination ability. . In particular, it is preferable that the carbon atom serving as the optical center is bonded to the para position relative to the position where the carbon atom is bonded to the benzene ring. In this case, the coordination ability is particularly large, and the durability against light and heat is excellent. Is possible.

Example 2
Molecular design of a compound having a structure represented by the following formula (19) was performed. The β-diketone ligand of this compound can be synthesized by the same synthesis method as in Example 1.

  By coordinating the β-diketone obtained as described above to europium ions and subsequently coexisting with triphenylphosphine oxide, a europium complex of the formula (19) is obtained. This europium complex is dispersed in the fluorine-based polymer of Example 1 to form the light emitting layer (phosphor layer) 3 of FIG. 1 to manufacture a light emitting device.

  The compound having the structure represented by the following formula (19) is excellent in solubility in a fluorine-based polymer due to its strong amorphous property, and can also be excellent in durability against light and heat as described above. .

However, since the phosphine oxide compound having the same structure is coordinated, the luminous intensity may be slightly reduced as compared with Example 1.

Example 3
Molecular design of a compound having a structure represented by the following formula (20) was performed. This compound can be synthesized by the synthesis method described above. The β-diketone ligand of this compound can be synthesized by the same synthesis method as in Example 1.

  By coordinating the β-diketone obtained as described above to europium ions and subsequently coexisting with diphosphine dioxide, a europium complex of the formula (20) can be obtained. Diphosphine dioxide can be synthesized, for example, by the method disclosed in Japanese Patent Application No. 2003-179811. This europium complex is dispersed in the fluorine-based polymer of Example 1 to form the light emitting layer (phosphor layer) 3 of FIG. 1 to manufacture a light emitting device.

A compound having a structure represented by the following formula (20) has a diphosphine dioxide ligand, and a chelating effect is added to the phosphine oxide ligand. It is possible to obtain a luminous intensity and lifetime superior to those of the first embodiment.

Example 4
Molecular design of a compound having a structure represented by the following formula (21) was performed. This compound can be synthesized by the synthesis method of Example 3. The produced europium complex is dispersed in the fluorine-based polymer of Example 1 to form the light emitting layer (phosphor layer) 3 of FIG. 1 to manufacture a light emitting device.

A compound having a structure represented by the following formula (21) has a diphosphine dioxide ligand, and a chelating effect is added to the phosphine oxide ligand. In addition, it is possible to obtain a luminous intensity and lifetime superior to those of a lighting device using the complex of Example 1 as a phosphor.

Example 5
Molecular design of a compound having a structure represented by the following formula (22) was performed. This compound can be synthesized by the same synthesis method as in Example 3. The produced europium complex is dispersed in the fluorine-based polymer of Example 1 to form the light emitting layer (phosphor layer) 3 of FIG. 1 to manufacture a light emitting device.

A compound having a structure represented by the following formula (22) has a diphosphine dioxide ligand, and a chelating effect is added to the phosphine oxide ligand. In addition, it is possible to obtain a luminous intensity and lifetime superior to those of a lighting device using the complex of Example 1 as a phosphor.

Example 6
Molecular design of a compound having a structure represented by the following formula (23) was performed. The β-diketone ligand of this compound can be synthesized by the same synthesis method as in Example 1. The europium complex produced in the same manner as in Example 1 is dispersed in the fluorine-based polymer of Example 1 to form the light emitting layer (phosphor layer) 3 in FIG. 1 to manufacture a light emitting device.

The compound having the structure represented by the following formula (23) is excellent in solubility in a fluorine-based polymer due to its strong amorphous property, and the coordination ability of β-diketone to rare earth ions is increased, and durability against light and heat. Can also be excellent.

Example 7
Molecular design of a compound having a structure represented by the following formula (24) was performed. The β-diketone ligand of this compound can be synthesized by the same synthesis method as in Example 1. The europium complex produced in the same manner as in Example 1 is dispersed in the fluorine-based polymer of Example 1 to form the light-emitting layer (phosphor layer) 3 in FIG. 1 to manufacture a light-emitting element.

The compound having the structure represented by the following formula (24) is excellent in solubility in a fluorine-based polymer due to its strong amorphous property, and the coordination ability of β-diketone to rare earth ions is increased, and durability against light and heat. Can also be excellent.

Example 8
This example is an example of a white illumination device, and a red rare earth complex represented by the formula (17) of Example 1, green (BaMgAl ₂₇ O ₁₇ : Eu, Mn, etc., for example, 520 nm) and blue (( Sr, Ca, Ba) ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu, for example, 450 nm) is combined to produce white light. These rare earth complexes and inorganic phosphors are dispersed in the polymer used in Example 1 to form the light emitting layer (phosphor layer) 3 of FIG. 1 to produce an organic-inorganic hybrid type white LED element.

  Also in this white lighting device, due to the strong amorphous nature of the rare earth complex, it is possible to make it excellent in solubility in a fluoropolymer and more excellent in durability against light and heat than a conventional element.

Example 9
This example is also an example of a white illumination device, in which an organic fluorescent layer containing a rare earth complex and an inorganic fluorescent layer are laminated. FIG. 2 is a cross-sectional view showing the configuration.

  As shown in FIG. 2, an LED is used as a light emitting element, and has a laminated structure of an inorganic fluorescent layer 13 and an organic fluorescent layer 14. That is, as shown in FIG. 2, the LED chip is placed as the light emitting element 12 in the recess of the LED frame 11. The LED chip 12 is made of, for example, a GaN-based semiconductor material, and has a light emission wavelength of, for example, 395 nm as a UV light source. The light emitting element 12 is not limited to an LED chip, and for example, an ultraviolet light emitting device such as a laser diode can be used. The LED chip 12 is provided with a pair of electrodes (not shown).

In the recess of the LED frame 11, an inorganic fluorescent layer 13 and an organic fluorescent layer 14 are stacked on the LED chip 12 in order from the bottom. The inorganic fluorescent layer 13 is made of a green ((Sr, Ca, Ba) ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu, for example, 520 nm), blue (BaMgAl ₂₇ O ₁₇ : Eu, Mn, for example, 450 nm) inorganic silicone 13b. It is dispersed in the resin 13 a and occupies a part of the concave portion of the LED frame 11. The organic fluorescent layer 14 is made of a fluorine-based polymer 14 a containing the red europium complex 14 b represented by the formula (17) in Example 1, and occupies the remaining portion of the concave portion of the LED frame 11. Yes. As the fluoropolymer 14a, for example, cefral (manufactured by Central Glass Co., Ltd.) can be used.

  Also in this white lighting device, due to the strong amorphous nature of the rare earth complex, it is possible to make it excellent in solubility in a fluoropolymer and more excellent in durability against light and heat than a conventional element. Moreover, since the inorganic fluorescent layer 13 and the organic fluorescent layer 14 are laminated, it is possible to prevent the rare earth complex (europium complex) 14b in the organic fluorescent layer 14 from coming into contact with the inorganic fluorescent material 13b in the inorganic fluorescent layer 13. It is possible to suppress the deterioration of the rare earth complex 14b as compared with Example 8.

Example 10
This example is also an example of a white illumination device, in which a light emitting device including an organic fluorescent layer containing a rare earth complex and a light emitting device including an inorganic fluorescent layer are arranged in different regions. FIG. 3 is a plan view showing the configuration. A cross-sectional view of the light emitting device (R, G + B) provided in each region is as shown in FIG.

  Among the light emitting devices (R, G + B) provided in each region, the red light emitting device (R) 1 is a red rare earth complex 5 (center emission wavelength is 615 nm, for example) represented by the above formula (17) of this embodiment. The organic fluorescent layer 3 and the LED chip 2 dispersed in a fluorine-based polymer (cefural: trade name, manufactured by Central Glass Co., Ltd.) 4 are included. The LED chip 2 having a central emission wavelength of 395 nm (InGaN) was used. Next, a light emitting device (G + B) 1 including an inorganic fluorescent layer 3 in which a green light emitting phosphor (for example, 520 nm) and a blue light emitting phosphor (for example, 450 nm) are dispersed in the polymer 4 as the phosphor particles 5 and the LED chip is used. create. These light emitting elements 1 are arranged as shown in FIG. 3 to form a flash device as a white illumination device.

Note that BaMgAl ₂₇ O ₁₇ : Eu, Mn is used as the green light emitting phosphor, and (Sr, Ca, Ba) ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu is used as the blue light emitting phosphor.

  Also in this flash device, due to the strong amorphous nature of the rare earth complex, it is possible to make the fluoropolymer superior in solubility and light and heat durability than conventional elements. In addition, since the light emitting device including the organic fluorescent layer containing the rare earth complex and the light emitting device including the inorganic fluorescent layer are arranged separately in different regions, the rare earth complex in the organic fluorescent layer is not included in the inorganic fluorescent layer. Contact with the inorganic phosphor can be prevented, and deterioration of the rare earth complex can be suppressed more than in Example 8.

Further, according to the flash device of the present embodiment, it is possible to improve the luminous intensity and the average color rendering index, and it is possible to obtain a clear image including a person when performing flash photography in a dark place. In the embodiment of the present invention described above, the aliphatic alkyl group bonded to the carbon at the optical center of the fluorescent complex having a β-diketone as a ligand is not limited to a methyl group, but other lower groups such as an ethyl group. Aliphatic alkyl groups can be used.

The figure explaining the structure of the illuminating device which concerns on one Embodiment of this invention. The figure explaining the structure of the illuminating device which concerns on one Embodiment of this invention. The figure explaining the structure of the illuminating device which concerns on one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Plastic cell, 2 ... Light emitting element, 3 ... Phosphor layer (light emitting layer), 4 ... Polymer matrix, 5 ... Phosphor particle.

Claims (5)

A fluorescent complex having a structure represented by the following formula (17) or formula (19):

(In the formula, Ph represents a phenyl group, and n-Oc represents an n-octyl group.)

(In the formula, Ph represents a phenyl group.) A fluorescent complex having a structure represented by the following formula (20), formula (21) or formula (22):

(In the formula, Ph represents a phenyl group, n-Oc represents an n-octyl group, and t-Bu represents a t-butyl group.)

(In the formula, Ph represents a phenyl group, and t-Bu represents a t-butyl group.)

(In the formula, Ph represents a phenyl group, and t-Bu represents a t-butyl group.) A fluorescent complex having a structure represented by the following formula (23):

(In the formula, Ph represents a phenyl group, and n-Oc represents an n-octyl group.) A fluorescent complex having a structure represented by the following formula (24):

(In the formula, Ph is a phenyl group, n-Oc is an n-octyl group, and Ad is an adamantyl group.)   An illumination device comprising: a light-emitting element; and a fluorescent layer disposed on a light-emitting surface side of the light-emitting element and including the fluorescent complex according to claim 1.

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