JPWO2016195080A1 - Phosphorescent light emitting material, method for emitting phosphorescence from phosphorescent light emitter, method for producing phosphorescent light emitting material, organic light emitting device and gas sensor - Google Patents

Abstract

To provide a phosphorescent material that emits phosphorescence at a high emission intensity at room temperature, using a phosphorescent material that does not emit phosphorescence at 25 ° C. The phosphorescent light emitting material of the present invention is a phosphorescent light emitting material in which a hollow body having a hollow region encloses a phosphorescent emitter, and phosphorescent radiation from the phosphorescent emitter at 25 ° C. is contained in the hollow body. This is not observed in a state where the phosphorescent light emitter is not formed, but is observed in a state where the phosphorescent light emitter is encapsulated in the hollow body.

Description

  The present invention relates to a phosphorescent material capable of obtaining high emission intensity at room temperature, a method for emitting phosphorescence from a phosphorescent material, and a method for producing the phosphorescent material.

When a phosphorescent substance transitions from the ground singlet state to the excited singlet state by energy absorption, then transitions from the excited triplet state to the excited singlet state by generating an intersystem crossing. It is a substance that emits phosphorescence. Here, since the transition from the excited triplet state to the ground singlet state is spin-forbidden, the speed is slow, and the excited triplet state generally has a long lifetime. For this reason, phosphorescent emitters are usually non-radiatively deactivated (thermally deactivated) by vibration of molecules while in the excited triplet state at room temperature, and phosphorescence emission cannot be observed. In order to observe phosphorescence, it is necessary to accelerate the spin inversion using the heavy atom effect, or to suppress the vibration by setting the phosphorescent light emitter to a cryogenic temperature lower than the liquid nitrogen temperature.
On the other hand, development of a light-emitting material that realizes phosphorescence emission at room temperature by suppressing the non-radiative deactivation of the phosphorescent light emitter regardless of the heavy atom effect is also being developed.

Non-Patent Document 1 discloses a light emitting material in which a phosphorescent light emitter is dispersed in cyclodextrin as a host material, and it is described that phosphorescent radiation has been confirmed from this light emitting material at room temperature.
In addition, as other reports, a light emitting material in which a phosphorescent light emitter is dispersed in polymethyl methacrylate (PMMA) (see Non-Patent Document 2), and a light emitting material in which a phosphorescent light emitter is dispersed in polyvinyl alcohol (PVA) (Non Patent) Reference 3) and luminescent materials in which phosphorescent emitters are dispersed in steroids (see Non-Patent Document 4), and in each document, phosphorescence emission was confirmed from these luminescent materials at room temperature. Have been described. In these luminescent materials, PMMA, PVA, and steroid are all used as host materials.

S. Scypinski, L. J. C. Love, Anal. Chem., 56, 322-327 (1984) J. L. Kropp, W. R. Dawson, J. Phys. Chem., 71, 4499-4506 (1967) H. A. Al-Attar, P. P. Monkman, Adv. Funct. Mater. 22, 3824-3832 (2012) S. Hirata, K. Thani, J. Zhang, T. Yamashita, H. Kaji, S. R. Marder, T. Watanabe, C. Adachi, Adv. Funct. Mater., 23, 3386-3397 (2013)

As described above, Non-Patent Documents 1 to 4 describe that phosphorescence emission at room temperature was confirmed from a luminescent material in which a luminescent material was dispersed in a host material such as cyclodextrin. However, when the present inventors examined these luminescent materials, it was found that there were the following problems.
That is, in the luminescent materials of Non-Patent Documents 1 to 4, phosphorescence emission at room temperature can be confirmed only when the luminescent material has a specific size or shape, and a luminescent material that falls outside that range is used. In such a case, the emission intensity of phosphorescence is significantly reduced at room temperature. For this reason, the kind of light-emitting body which can be used is restrict | limited and there exists a problem that versatility is low. Further, in these light emitting materials, a phenomenon in which light emitters aggregate in the host matrix is observed. For this reason, it is difficult to uniformly form the light emitting layer, and the light emitting performance inherent to the light emitter cannot be sufficiently exhibited. Further, since the host material such as cyclodextrin used in Non-Patent Documents 1 to 4 is an insulator, it is difficult to impart a function as a semiconductor to the light emitting material, and the application range of the light emitting material is also limited. .

Therefore, the present inventors focused on a hollow body having a hollow region as a host material for solving these problems, and examined the presence or absence of phosphorescence emission at room temperature in combination with various phosphorescent emitters. It was found for the first time that phosphorescence with high emission intensity can be confirmed at room temperature. Non-Patent Documents 1 to 4 do not describe any combination of a hollow body having such a hollow region with a phosphorescent light emitter. From these documents, a hollow body having a hollow region and various phosphorescent light emitters are described. It is unpredictable that phosphorescence with high emission intensity can be confirmed at room temperature by combining.
Under such circumstances, the present inventors have further investigated the light emission characteristics of a light emitting material in which a hollow body having a hollow region and a phosphorescent light emitter are combined, and phosphorescence capable of obtaining phosphorescence with high light emission intensity at room temperature. Research was conducted with the aim of finding luminescent materials.

As a result of intensive studies, the present inventors have found that phosphorescence emission, which does not show phosphorescence emission at 25 ° C., is encapsulated in a hollow body having a hollow region, and phosphorescence emission is recognized even at room temperature. The present inventors have found that a phosphorescent material that emits phosphorescence with high emission intensity at room temperature can be realized. Furthermore, the present inventors have found that this phosphorescent material does not easily aggregate phosphorescent materials and is excellent in handleability. Specifically, the present invention has the following configuration.
[1] A phosphorescent material in which a hollow body having a hollow region encloses a phosphorescent emitter, and phosphorescent radiation from the phosphorescent emitter at 25 ° C. is obtained by encapsulating the phosphorescent emitter in the hollow body. A phosphorescent material that is not recognized in the absence of the phosphor but is recognized when the phosphor is encapsulated in the hollow body.
[2] The phosphorescent material according to [1], wherein the hollow region has a space in which the phosphorescent body can contain one or more molecules and less than two molecules.
[3] The phosphorescent material according to [1] or [2], wherein the hollow body having the hollow region is an organometallic structure.
[4] The phosphorescent material according to [3], wherein the organometallic structure is a zeolite imidazolate structure.
[5] The phosphorescent material according to [3] or [4], wherein the metal ion of the organometallic structure is a zinc ion.
[6] The phosphorescent material according to any one of [1] to [5], wherein the phosphorescent emitter does not contain a metal atom.
[7] The phosphorescent material according to any one of [1] to [6], wherein the phosphorescent emitter is a π-conjugated planar molecule.
[8] The phosphorescent material according to [7], wherein the π-conjugated planar molecule has a condensed polycyclic structure in which two or more benzene rings are condensed.
[9] The phosphorescent material according to [8], wherein the condensed polycyclic structure is a condensed polycyclic skeleton structure having a rotational symmetry axis.
[10] The [π], wherein the π-conjugated planar molecule is a D-substituted product in which a part or all of the hydrogen atoms of coronene or coronene are substituted with ² H (deuterium D). Phosphorescent material.
[11] The phosphorescent material according to [8], wherein the π-conjugated planar molecule has a condensed polycyclic structure represented by the following formula.
[12] The phosphorescent material according to any one of [8] to [11], wherein the condensed polycyclic structure does not have a substituent.

[13] A phosphorescent composition comprising the phosphorescent material according to any one of [1] to [12] and a substance having a heavy atom effect.
[14] The phosphorescent composition according to [13], wherein the substance having a heavy atom effect is a gas or a liquid.
[15] The phosphorescent composition according to [13] or [14], wherein the substance having a heavy atom effect is a gas, and further includes a gas of a substance not having a heavy atom effect.
[16] The phosphorescent composition according to [13] or [14], wherein the substance having a heavy atom effect is a liquid and further includes a liquid of a substance not having a heavy atom effect.
[17] The phosphorescent composition according to [13] or [14], comprising a solution in which the substance having the heavy atom effect is dissolved in a solvent.
[18] The substance having the heavy atom effect is at least one selected from Group 18 elements, compounds containing Group 17 elements, compounds containing Group 16 elements, and metal complexes [13] to [17. ] The phosphorescent composition of any one of these.
[19] The phosphorescent composition according to [18], wherein the substance having a heavy atom effect is Xe gas.
[20] The phosphorescent composition according to [18], wherein the substance having a heavy atom effect is a halogenated alkane.

[21] A method of emitting phosphorescence from the phosphorescent emitter at the specific temperature by encapsulating a phosphorescent emitter that does not emit phosphorescence at a specific temperature in a hollow body having a hollow region.
[22] A phosphorescent emitter that does not emit phosphorescence at a specific temperature is allowed to coexist with a substance having a heavy atom effect in a state of being enclosed in a hollow body having a hollow region, and phosphorescence is emitted from the phosphorescent emitter at the specific temperature. The method according to [21], wherein radiation is performed.
[23] A method for producing a phosphorescent material, comprising a step of encapsulating a phosphorescent material that does not emit phosphorescence at a specific temperature in a hollow body having a hollow region.
[24] The method for producing a phosphorescent material according to [23], wherein the step is performed by synthesizing the hollow body so as to enclose the phosphorescent body.
[25] The hollow body is a metal organic structure,
The phosphorescence emission according to [24], wherein the step is performed by coordinating the organic ligand and the metal ion of the metal salt in a mixture containing the organic ligand, the metal salt and the phosphorescent emitter. Material manufacturing method.
[26] An organic light-emitting device comprising the phosphorescent material according to any one of [1] to [12].
[27] An organic light-emitting device comprising the phosphorescent composition according to any one of [13] to [20].
[28] The organic light-emitting device according to [26] or [27], which is an organic electroluminescence device.
[29] The organic light-emitting device according to any one of [26] to [28], wherein phosphorescence is observed at room temperature.
[30] A gas sensor comprising the phosphorescent material according to any one of [1] to [12].

  The phosphorescent material of the present invention can recognize phosphorescence having high emission intensity at room temperature while using a phosphorescent material that does not emit phosphorescence at 25 ° C. In addition, this phosphorescent material does not easily aggregate phosphorescent materials, and excellent film forming properties and light emitting characteristics can be obtained.

It is a schematic diagram which shows an example of the hole which the phosphorescence-emitting material of this invention and this phosphorescence-emitting material have. It is a schematic sectional drawing which shows the layer structural example of an organic electroluminescent element. 2 is a powder X-ray diffraction spectrum of the phosphorescent material of Example 1, the phosphorescent material of Example 2, and ZIF-8 of Comparative Example 1. FIG. It is the fluorescence and phosphorescence spectrum in the phosphorescence thin film containing the coronene of Example 3, and ZIF-8, and the coronene of the comparative example 2 in the dichloromethane solution. Emission intensity transient decay at 560 nm of the phosphorescent light-emitting thin film containing coronene and ZIF-8 of Example 3, the D-substitution of coronene of Example 4 and the phosphorescent thin film containing ZIF-8, and the coronene PMMA-dispersed thin film of Comparative Example 3 It is a curve. Temperature Dependence of Luminescence Lifetime of Phosphorescent Light-Emitting Thin Film Containing Coronene and ZIF-8 of Example 3, Phosphorescent Thin Film Containing D Substitute of Coronene and ZIF-8 of Example 4, and Coronene PMMA Dispersive Thin Film of Comparative Example 3 It is. It is a phosphorescence spectrum of the phosphorescence-emitting material containing the compound 37 of Example 5, and ZIF-8. It is a luminescence intensity transient decay curve in 560 nm of the phosphorescence-emitting material containing the compound 37 of Example 5, and ZIF-8. (A) is a fluorescence and phosphorescence spectrum measured by placing compound 34 under a reduced pressure of 10 ⁻³ Pa, and (b) is a compound 34 of 100% Xe gas. (C) is a fluorescence and phosphorescence spectrum measured by placing Compound 34 in the atmosphere. After irradiating the phosphorescent light emitting material of Example 1 with excitation light, a light emission intensity transient decay curve when 100% Xe gas is introduced after elapse of 6 seconds and a light emission intensity transient decay curve measured without introducing Xe gas. is there. And emission intensity transient decay curve solution was measured for the mixtures obtained by mixing the phosphorescent material with dibromomethane in Example 1 (CH 2 _{Br 2),} phosphorescent materials that do not mix the solutions dibromomethane (CH 2 _{Br 2)} It is the luminescence intensity transient decay curve measured about.

Hereinafter, the contents of the present invention will be described in detail. The description of the constituent elements described below may be made based on typical embodiments and specific examples of the present invention, but the present invention is not limited to such embodiments and specific examples. In the present specification, a numerical range represented by using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value. In addition, the isotope species of the hydrogen atom present in the molecule of the compound used in the present invention is not particularly limited. For example, all the hydrogen atoms in the molecule may be ¹ H, or a part or all of the hydrogen atoms are ² H. (Deuterium D) may be used.

<Phosphorescent material>
The phosphorescent light emitting material of the present invention is a phosphorescent light emitting material in which a hollow body having a hollow region encloses the phosphorescent light emitter, and phosphorescent radiation from the phosphorescent light emitter at 25 ° C. is contained in the hollow body. It is not recognized in a state where the phosphorescent light emitter is not formed, but is recognized in a state where the phosphorescent light emitter is encapsulated in the hollow body.
The phosphorescent material of the present invention can confirm phosphorescence having high emission intensity even at room temperature while using a phosphorescent material that does not emit phosphorescence at 25 ° C. This is presumed to be due to the following reason.
In other words, phosphorescent emitters in which no phosphorescence emission is observed at 25 ° C. are observed to emit phosphorescence because their triplet excitons are thermally deactivated (non-radiation deactivation) by molecular vibrations at 25 ° C. It is thought that there is nothing. In contrast, in the phosphorescent material of the present invention, the phosphorescent emitter is encapsulated in a hollow body having a hollow region and surrounded by an atomic network structure, so that the phosphorescent emitter is in an excited triplet state. When transitioned, it is presumed that vibrations of molecules are suppressed and non-radiative deactivation such as thermal deactivation is suppressed. As a result, the phosphorescent body transitioned to the excited triplet state efficiently deactivates by emitting phosphorescence (radiation deactivation), and high intensity phosphorescence emission can be recognized even at room temperature. Further, in this phosphorescent material, since the phosphorescent material included in the hollow region of the hollow body is isolated for each hollow region, the phosphorescent material is less likely to aggregate and has good film formability and light emitting characteristics. Can be obtained. Furthermore, since the hollow body having a hollow region can easily control the shape and size of the hollow region by its molecular design, the above-described effects can be obtained regardless of the molecular shape and size of the phosphorescent emitter. Can be realized.
Hereinafter, the phosphorescent light emitter and the hollow body having a hollow region used in the phosphorescent light emitting material of the present invention will be described in detail.

[Phosphorescent emitter]
A phosphorescent emitter is a substance that generates phosphorescence upon supply of energy, and phosphorescence emission at 25 ° C. is not recognized when not encapsulated in a hollow body, but is recognized when encapsulated in a hollow body. .
In the present invention, “no phosphorescence emission is observed” means that the emission lifetime of phosphorescence emitted when irradiated with excitation light of 340 nm under the temperature condition of 25 ° C. in the atmosphere is less than 1 μs, or phosphorescence emission "Phosphorescence emission is recognized" means that the emission lifetime of phosphorescence emitted when irradiated with excitation light of 340 nm in the atmosphere at 25 ° C. is 1 μsec or more. Say. Further, in the above [1], “not recognized in the state where the phosphorescent body is not encapsulated in the hollow body” means that a 0.01 mM (mmol / L) concentration solution of the phosphorescent body is heated to 25 ° C. in the atmosphere. This refers to the case where the emission lifetime of phosphorescence is less than 1 μsec or no phosphorescence emission is observed when 340 nm excitation light is irradiated under temperature conditions. The light emission lifetime is the time from the start of light emission until the light emission intensity decreases to half of the maximum value.
In this specification, “room temperature” means 25 ° C.
The “state not encapsulated in the hollow body” and the “state encapsulated in the hollow body” in the present invention will be described in the section “Hollow body”.

As the phosphorescent emitter, those satisfying the conditions of the present invention can be widely used. For example, the phosphorescent emitter may be selected from a group of compounds that do not contain heavy metal atoms, or may be selected from a group of compounds that do not contain metal atoms. Further, the phosphorescent emitter may be selected from a group of compounds consisting only of atoms selected from the group consisting of carbon atoms, hydrogen atoms, nitrogen atoms, oxygen atoms, sulfur atoms, boron atoms, phosphorus atoms, and halogen atoms. It is also possible to select from a group of compounds consisting only of carbon atoms, hydrogen atoms, nitrogen atoms and oxygen atoms, and further selecting from a group of compounds consisting only of carbon atoms and hydrogen atoms. It is also possible.
As an example of a preferable group of compounds that can be used as the phosphorescent emitter, “π-conjugated planar molecule” can be given.

“Π-conjugated planar molecule” means an atomic group that constitutes a π-conjugated system, and this atomic group has a planar structure (hereinafter referred to as “π-conjugated planar structure”). The π-conjugated planar molecule may be composed only of a π-conjugated planar structure, or may have a structure other than the π-conjugated planar structure.
In the π-conjugated planar molecule, the π-conjugated planar structure is preferably an aromatic ring. Π-conjugated planar molecules with an aromatic ring tend to be hard, and the radiative deactivation path proceeds more easily than the non-radiative deactivation path when relaxing from the excited triplet state. It is done. As a result, phosphorescence can be emitted efficiently. Examples of the aromatic ring include a benzene ring and a condensed polycyclic structure having a structure in which two or more benzene rings are condensed. Examples of the condensed polycyclic structure include naphthalene, phenanthrene, triphenylene, chrysene, pyrene, benzoperylene, coronene and the like.
The π-conjugated planar molecule is preferably a D-substituted product in which some or all of the hydrogen atoms are substituted with ² H (deuterium D). Since the CD bond is less likely to expand and contract than the CH bond, the D-substituted product can suppress non-radiative deactivation from the excited triplet state more efficiently than the H-form, and can emit phosphorescence more efficiently. .
In the π-conjugated planar molecule, the π-conjugated planar structure may be substituted with a substituent. In particular, secondary amines and tertiary amines having a structure in which the π-conjugated planar structure is substituted with an amino group tend to emit phosphorescence having a large emission intensity at room temperature for a long time, and are preferably used as a phosphorescent material. it can. The amino group is preferably a substituted or unsubstituted diarylamino group or a substituted or unsubstituted dialkylamino group, more preferably a substituted or unsubstituted diphenylamino group.

In the following, specific examples of π-conjugated planar molecules will be exemplified. However, π-conjugated planar molecules that can be used in the present invention should not be construed as being limited by these specific examples.
π-conjugated planar molecules include 2-dimethylaminotriphenylene, 2-diphenylaminotriphenylene, 2-diethylaminofluorene, 2-dipropylaminofluorene, 3-amino-2-dimethylfluorene, 2,7-bis (N-phenyl- N- (4′-N, N-diphenylamino-biphenyl-4-yl))-9,9-dimethyl-fluorene, 9,9-dimethyl-N, N′-diphenyl-N, N′-di-m -Tolylfluorene-2,7-diamine, 2,7-bis [phenyl (mtolyl) amino] -9,9'-spirofluorene, N, N, N ', N'-tetraphenylbenzidine, N, N' -Diphenyl-N, N'-di (m-tolyl) -benzidine, 3,3 ', 5,5'-tetramethyl-benzidine, 4,4'-bis [di (3,5-xylyl) amino] -4 "-phenyltriphenylamine, N, N, N ', N'-tetrakis (p-tolyl) benzidine, 4,4'-bis [N- (1-naphthyl) -N-phenylamino] -4" -Phenyltriphenylamine, N-phenyl-2naphthylamine, N, N'-diphenyl-benzidine, (phenanthren-9-yl) -phenyl-amine, N-phenyl-N-pyren-3-yl-amine, diethyl- And pyren-1-yl-amine. By using these compounds (π-conjugated planar molecules), phosphorescence having a long lifetime and high emission intensity can be observed at room temperature. In addition, a D-substituted product in which the hydrogen atom of the aromatic ring of these compounds is substituted with ² H (deuterium D), and a halogen-substituted product in which a halogen atom such as fluorine is substituted are also preferably used as the π-conjugated planar molecule. it can.

As the π-conjugated planar molecule, a compound represented by the following formula can also be preferably used. The compound represented by the following formula is a D-substituted product in which at least one of the hydrogen atoms may be substituted with a substituent, or a part or all of the hydrogen atoms are substituted with ² H (deuterium D). Also good.

Among these π-conjugated planar molecules, a compound having a condensed polycyclic structure in which two or more benzene rings are condensed, such as compounds 23 to 41, and at least one hydrogen atom of the compound having the condensed polycyclic structure is substituted. It is preferable to use a D-substituted product in which a part of or all of the hydrogen atoms of a derivative substituted with a group or a compound having a condensed polycyclic structure thereof is substituted with ² H (deuterium D). Among them, a compound having a condensed polycyclic skeleton structure having a rotationally symmetric axis and a condensed polycyclic compound having a rotationally symmetric axis of the compound molecule itself (the entire structure of the molecule including a substituent) can be preferably used. Particularly preferred is compound 34 (coronene), a derivative in which at least one of the hydrogen atoms of compound 34 is substituted with a substituent, or a part or all of the hydrogen atoms of compound 34 is substituted with ² H (deuterium D). More preferred is the unsubstituted compound 34 or its D-substituted product.
Further, in the compounds 36 to 41 having a structure in which the adjacent benzene rings are not bonded by a single bond such as the first benzene ring and the fifth benzene ring of the compound 36 or the compound 37, instead of the single bond, There is a phenomenon in which two existing hydrogen atoms repel each other because they are close to each other, and benzene rings having the hydrogen atoms are flipped. For this reason, the compounds 36 to 41 having such a structure tend to be non-radiatively deactivated and hardly emit phosphorescence. On the other hand, when these compounds 36 to 41 are encapsulated in a hollow body, flipping is effectively suppressed and phosphorescence is easily emitted, and the emission intensity of phosphorescence at room temperature can be significantly increased.
In addition to these, the phosphorescent emitter used in the present invention can also include a π-conjugated planar molecule having an excellent hole transport function. For specific examples of the π-conjugated planar molecule having excellent hole transport ability, the following specific examples of the hole transport material can be referred to.
One type of phosphorescent emitter described above may be used alone, or two or more types may be used in combination.

  The content of the phosphorescent material in the phosphorescent material varies depending on the type of phosphorescent material and the type of hollow body combined with the phosphorescent material, but is preferably 0.001% by mass or more based on the total amount of the phosphorescent material. The content is more preferably 0.01% by mass or more, and further preferably 0.1% by mass or more. The content of the phosphorescent emitter is preferably 50% by mass or less, more preferably 10% by mass or less, and still more preferably 5% by mass or less with respect to the total amount of the phosphorescent material.

<Hollow body having hollow region>
A hollow body having a hollow region is a substance capable of enclosing a phosphorescent emitter.
In the present invention, the “hollow region” refers to a three-dimensional space region formed by bonding the atoms constituting the hollow body in a network shape so as to surround a certain space. In addition, “the state in which the phosphorescent body is encapsulated in the hollow body” means that the phosphorescent body is contained in the space of the hollow region and the bonds of the atoms constituting the hollow body are not cleaved. It means a state where it cannot be taken out of the hollow body, and “a state where the phosphorescent light emitter is not encapsulated in the hollow body” means a state where the phosphorescent light emitter is not accommodated in the space of the hollow region of the hollow body. Say that. In the present invention, the fact that “phosphorescent radiation from a phosphorescent emitter at 25 ° C. is not recognized when the phosphorescent emitter is not encapsulated in a hollow body” corresponds to the fact that the hollow body is not used. Thus, when the phosphorescent light emitting material is prepared, the phosphorescence emission that was recognized when the phosphorescent material was prepared using the hollow body is not recognized.
The fact that the phosphorescent body is encapsulated in the hollow body means that when the hollow body encapsulating the phosphorescent body is raised above the sublimation temperature of the phosphorescent body, the phosphorescent body is not encapsulated in the hollow body. It can be determined that no decrease in mass as observed when the temperature is raised above the sublimation temperature is observed, and that the emission spectrum of the phosphorescent material is observed.
The hollow body constituting the phosphorescent material of the present invention is not particularly limited as long as it has at least one hollow region that can contain the phosphorescent material. For example, the hollow body may form a network like a porous coordination material, or may be an aggregate of granular bodies or an aggregate of aggregates. When adopting an aggregate of granules, each granule contained in the aggregate may have only one hollow region that can contain the phosphorescent material, or two or more. Good.
FIG. 1 shows a phosphorescent light emitting material in which a zeolite imidazolate structure 11 includes a phosphorescent light emitter 12 as a hollow body having a hollow region as an example of the phosphorescent light emitting material of the present invention. The zeolate imidazolate structure 11 is a porous coordination material classified into a metal organic structure described later. In the case of this phosphorescent material, a network structure is formed by continuously coordinating and bonding methylimidazole with metal ions, and the phosphorescent material 12 is included in a space surrounded by the network structure. FIG. 1 is a schematic view showing a part of the phosphorescent material in a simplified manner for the sake of simplicity. The phosphorescent material shown in FIG. 1 is an example of the phosphorescent material of the present invention, and the phosphorescent material of the present invention is not limited to the specific example shown in FIG.

The hollow region of the hollow body preferably has a space in which one or more phosphorescent emitters can be encapsulated. The upper limit of the number of phosphorescent phosphor molecules that can be encapsulated in the space of the hollow region is preferably less than 1.8 molecules, more preferably less than 1.6 molecules, and more preferably 1.4 molecules. It is particularly preferred that it is less than.
The size of the space in the hollow region (hollow volume) is defined by the van der Waals diameter of each atom constituting the outer edge of the hollow region, and the size of the phosphor phosphor molecule depends on the van der Waals diameter of its constituent atoms. It is prescribed. The number of phosphorescent emitter molecules that can be encapsulated in the hollow body can be controlled based on the hollow volume of the hollow body obtained from the van der Waals diameter of these atoms and the size of the phosphorescent emitter molecules. In addition, in a hollow body having a hollow region, as the hollow volume increases, the number of phosphorescent phosphor molecules that can be included tends to increase, but depending on the spatial shape of the hollow region, there is a sufficient hollow volume. In some cases, however, the phosphorescent emitter cannot be included. Therefore, the control of the number of phosphorescent phosphor molecules that can be encapsulated in the hollow body is preferably performed in consideration of the spatial shape of the hollow region of the hollow body, both of the hollow volume of the hollow body and the size of the phosphorescent phosphor molecules. . Specifically, the hollow volume of the hollow body, the spatial shape of the hollow region, and the molecular size of the phosphorescent emitter, which are expected to obtain the desired inclusion volume, are determined, and the atoms and atomic groups that achieve this are determined. Molecular design is performed by selecting combinations using van der Waals diameter as an index. Factors such as van der Waals diameter that determine the hollow volume of the hollow body, the spatial shape of the hollow region, and the molecular size of the phosphorescent emitter can be determined using DFT (quantum chemical calculation). Specific examples of the molecular design include molecular modifications such as introducing a substituent into the hollow body and converting the hydrophobic group of the hollow body into a hydrophilic group. By introducing a substituent into the hollow body, the hollow volume and the hollow shape can be controlled, and the structure of the hollow body can be changed by converting the hydrophobic group into a hydrophilic group. In particular, when a phenyl group is introduced into the hollow body, the state of the outer edge that defines the hollow region can be changed, and the number of phosphorescent phosphor molecules that can be encapsulated in the hollow body can be effectively controlled.

  In the network structure of atoms constituting the outer edge of the hollow region, the maximum diameter of the network (hole) is preferably smaller than the maximum width of the molecules of the phosphorescent material. Thereby, it is possible to prevent the phosphorescent emitter from falling out of the hollow region of the hollow body, and the phosphorescent emitter can be surely included in the hollow body. For example, in the ZIF-8 that is the above-described zeolite imidazolate structure, the maximum diameter L of the holes 13 on the outer edge is 0.34 nm. Therefore, the phosphorescent emitter 12 combined with ZIF-8 preferably has a maximum molecular width of 0.4 nm or more, more preferably 0.6 nm or more, and further preferably 1.0 nm or more. The maximum diameter of vacancies at the outer edge of the hollow region can be measured by X-ray structure analysis, the maximum width of the phosphor phosphor can be measured by X-ray structure analysis, and can be calculated by quantum chemistry calculations. Is possible.

  An example of a preferable material that can be used as a hollow body having a hollow region is “Metal Organic Framework (MOF).” The metal organic structure is composed of a metal ion and a crosslinkable organic ligand. Is a porous material that forms a network structure by continuously coordinating bonds, and the shape and size of the pores can be constructed relatively freely by selecting metal ions and designing the molecular structure of the organic ligand. In addition, there is an advantage that electrical functions such as semiconductor characteristics can be provided.

  The metal ion of the metal organic structure is not particularly limited, but is selected from Cu, Zn, Co, In, Al, Fe, V, Mg, Mn, Ni, Ru, Mo, Cr, W, Rh, and Pd. Examples include ions of metal elements, more preferably ions of metal elements selected from Cu, Zn, Co, In, Al, Fe and V, and further preferably selected from Cu, Zn and Co. Metal element ions, particularly preferably Zn ions.

Examples of the organic ligand of the metal organic structure include dicarboxylic acid, tricarboxylic acid, tetracarboxylic acid, imidazole, benzimidazole, azabenzimidazole, and derivatives thereof. Among them, dicarboxylic acid or a derivative thereof, It is preferably imidazole or a derivative thereof, and more preferably methylimidazole. In addition, a zeolite imidazolate structure obtained from an organic ligand having an imidazole ring can be suitably used as a hollow body containing a phosphorescent material because the pore diameter is relatively small.
Examples of the dicarboxylic acid that can be used as the organic ligand include isophthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, and biphenyldicarboxylic acid, and are terephthalic acid. preferable. Examples of the tricarboxylic acid include 1,2,3-benzenetricarboxylic acid, 1,3,5-benzenetricarboxylic acid, and the like, and examples of the tetracarboxylic acid include 1,2,3,4-benzenetetracarboxylic acid, Examples thereof include 1,2,4,5-benzenetetracarboxylic acid.
These organic ligands may be substituted with a substituent. Substituents that can be substituted on the organic ligand are not particularly limited, but include hydroxyl groups, amino groups, alkoxy groups such as methoxy groups and ethoxy groups, alkyl groups such as methyl groups and ethyl groups, nitro groups, methylamino groups and Examples thereof include substituted amino groups such as dimethylamino group, cyano groups, and halogen groups such as chloro group, bromo group, and fluoro group.

  Specific examples of metal organic structures include ZIF-8, MIL-53 (Al), DUT-5, MOF-5, MOF-76 (Yb), MOF-76 (Y), MOF-76 (Tb), and MOF. -76 (Co), MOF-74 (Co), MOF-74 (Zn), MOF-74 (Mg), MIL-101 (Cr), UiO-67, UiO-66, UiO-66-1, 4- Naph, MIL-125, MIL-68 (Ga), Al-bpdc and the like can be mentioned, among which ZIF-8, MOF-5 and MOF-74 are preferable, and ZIF-8 is more preferable. preferable. However, the metal organic structure that can be used in the present invention should not be limited to these specific examples.

In addition, the symbol shown by the specific example of said organometallic complex has the following meaning, respectively.
ZIF-8: Zn (min) ₂
min: metyl-imidazolate
MIL-53 (Al): Al (OH) (bdc)
bdc: benzene-1,4-dicarboxylate
DUT-5: Al (OH) (bpdc)
bpdc: biphenyl-4,4'-dicarboxylate
MOF-5: Zn ₄ (bdc) ₃
MOF-76 (M): M (btc)
M: Yb, Y, Tb or Co
btc: benzene-1,3,5-triscarboxylate
MOF−74 (M) = M ₂ (dobdc)
M: Co, Zn or Mg.
dodbc: 2,5-dioxido-benzene-1,4-dicarboxylate
MIL-101 (Cr): Cr ₃ O (OH) (bdc) _{3
UiO-67: Zr 6 O 4} (OH) 4 (bpdc) 6
_{UiO-66: Zr 6 O 4} (OH) 4 (bdc) 6
_{UiO-66-1,4-Naph: Zr 6} O 4 (OH) 4 (ndc) 6
ndc: naphthalene-1,4-dicarboxylate
MIL-125: Ti ₈ O ₈ (OH) ₄ (bdc) ₆
MIL-68 (Ga): Ga (OH) (bdc)
Al-bpdc: Al (OH) (bpdc)
The hollow body which has the hollow area demonstrated above may be used individually by 1 type, and may be used in combination of 2 or more types.

As an example of a material that can be used as a hollow body, a molecule having a relatively low molecular weight that does not have a network can be cited. The shape of such a molecule may be any of a cage shape, a spherical shape, a capsule shape, a tube shape, and the like. The molecular weight is preferably 800 or more, and more preferably 1000 or more. Although the upper limit of the molecular weight is not particularly limited, for example, it can be employed from the range of 5000 or less, 3000 or less, or 2000 or less. When adopting a granular material, the particle size is preferably 0.1 nm or more, more preferably 0.5 nm or more, more preferably 20 nm or less, and more preferably 10 nm or less. .
The hollow body molecule herein may be composed of a complex such as a metal complex. Examples of the metal complex include transition metal complexes, and examples thereof include transition metal complexes such as Pt and Pd. Examples of the ligand include bidentate ligands, tridentate ligands, and tetradentate ligands, and specific examples include diamine-based bidentate ligands such as ethylenediamine. it can. Moreover, it is preferable to select a ligand having a structure capable of forming a cage structure including a hollow region by appropriately coordinating. For example, a cage molecule composed of a plurality of metals and a plurality of ligands can be synthesized by using a tridentate or higher ligand. A ligand including a structure having a lone electron pair such as a nitrogen atom or an oxygen atom coordinated to a metal atom can be preferably used. As the structure contained in the ligand, a heteroaromatic ring containing a nitrogen atom or an oxygen atom as a ring constituent atom can be preferably exemplified, and examples thereof include a pyridine ring, a pyrimidine ring, a pyrazine ring, and a triazine ring. . In addition, the ligand can preferably include an aromatic ring such as a benzene ring as a linking group. As specific ligands, a ligand having a single ring structure such as a pyrazine ring or a 6-membered aromatic ring such as a benzene ring or a triazine ring, the 1,3,5-position or 2, A structure in which a pyridine ring is substituted at the 4th and 6th positions, and a 6-membered aromatic ring such as a benzene ring or a triazine ring, with a pyridine ring at the 1st, 3rd, 1st, 4th or 2nd and 4th positions. Examples thereof include a substituted structure and a structure having a condensed ring such as porphine and having four pyridine rings substituted at symmetrical positions of the porphine ring system. By employing such a ligand, it is possible to form a complex having a regular polyhedral structure such as a regular tetrahedral structure or an upright surface structure.
Specific examples of hollow transition metal complexes include, for example, M. Fujita et al., J. Am. Chem. Soc. 2004, 126, 9172-9173; M. Fujita et al., J. Am. Chem. Soc. 2005, 127, 2798-2799; M. Fujita et al., Angew. Chem. Int. Ed., 2005, 44, 1810-1813.

  The content of the hollow body having a hollow region varies depending on the type of phosphorescent light emitter and the type of hollow body combined with the phosphorescent light emitter, but is preferably 50% by mass or more based on the total amount of the phosphorescent light emitting material, 90 % Or more is more preferable, and it is further more preferable that it is 95 mass% or more. The content of the hollow body having a hollow region is preferably 99.999% by mass or less, more preferably 99.99% by mass or less, and more preferably 99.9% by mass with respect to the total amount of the phosphorescent material. More preferably, it is% or less.

[Combination of phosphorescent body and hollow body having hollow region]
The combination of the phosphorescent body and the hollow body having a hollow region is not particularly limited, but the number of molecules of the phosphorescent body that can be encapsulated in the hollow body is in the above preferred range, and the phosphorescent body that is encapsulated in the hollow body Is preferably selected so that the pores of the hollow body that define the outer edge of the hollow region are sufficiently smaller than the size of the molecules of the phosphorescent material. Further, since the hollow body can also function as a host material of the phosphorescent body, it is preferable to employ a combination in which at least the excited triplet energy level of the hollow body is larger than that of the phosphorescent body. It is more preferable to employ a combination in which both the excited singlet energy level and the excited triplet energy level of the phosphorescent material are larger than that of the phosphorescent emitter. This makes it possible to confine the singlet excitons and triplet excitons generated in the phosphorescent body in the molecules of the phosphorescent body, and the excited singlet energy and excited triplet energy generated in the hollow body. The phosphor can be easily moved to the phosphorescent light emitter, and the light emission efficiency of the phosphorescent light emitter can be sufficiently extracted.
Preferred combinations of the phosphorescent body and the hollow body having a hollow region include coronene or its D-substituted product and ZIF-8, perylene or its D-substituted product and ZIF-8, triphenylene or its D-substituted product and ZIF-8, Anthracene or a D-substituted product thereof, ZIF-8 and the like can be mentioned.
Moreover, the phosphorescent material of the present invention may be composed of only a phosphorescent emitter and a hollow body having a hollow region, or may contain other molecules.

<Phosphorescent composition>
The phosphorescent composition of the present invention includes the phosphorescent material of the present invention and a substance having a heavy atom effect.
The description of the phosphorescent material of the present invention, the preferred range, and specific examples thereof can be referred to the “phosphorescent material” column.
In the present invention, the “substance having a heavy atom effect” refers to a transition from an excited singlet state to an excited triplet state and an excited triplet state to a ground singlet state by relaxing spin forbiddenness in electronic transitions between different terms. A substance that has the effect of increasing the probability of transition to. Whether or not the substance is “a substance having a heavy atom effect” is determined by a spin-orbit interaction constant. Spin-orbit interaction constant is preferably not less than 500 cm ^-1, more preferably at least 1000 cm ^-1, 1500 cm ^-1 or more is more preferable.
In the phosphorescent composition of the present invention, such a substance having a heavy atom effect is incorporated into the hollow body of the phosphorescent material, and the external heavy atom effect causes inter-term transition from the excited singlet state to the excited triplet state of the phosphorescent material. It is presumed that the deactivation process from the crossing or excited triplet state to the ground singlet state is accelerated, the time until the phosphorescence intensity is saturated is shortened, and the emission lifetime is shortened. Therefore, by adjusting the concentration of the substance having the heavy atom effect as appropriate and applying it, or by appropriately selecting the type and combination of the substance having the heavy atom effect to be used, the emission lifetime can be set to an arbitrary length. Can be controlled.

  As a substance having a heavy atom effect, an element having a large spin-orbit interaction constant or a compound containing such an element can be used, and specifically, a second element such as Ar, Kr, Xe, or Rn can be used. Examples include compounds containing Group 17 elements (halogens) such as Group 18 elements (rare gases), halogenated alkanes, and halogenated arenes, compounds containing Group 16 elements (chalcogens) such as Se and Te, and metal complexes. Among them, it is preferable to use a rare gas or a halide. Further, among rare gases, Xe gas is preferable, and among halides, bromide is preferable, and iodide is more preferable. The larger the number of halogen substitutions, the better. These substances having a heavy atom effect may be used alone or in combination of two or more.

  The state of the substance having a heavy atom effect is not particularly limited. Under the environment where the phosphorescent composition is used (for example, at room temperature of 1 atm), a substance in any state of solid, liquid, or gas can be used, but it exists as a gas or liquid. It is preferable to use one. By using a substance having a heavy atom effect, the emission lifetime of the phosphorescent emitter can be effectively controlled by the heavy atom effect of the substance. In addition, when a substance having a heavy atom effect is used as a substance having a heavy atom effect, the concentration may be adjusted by mixing a gas having a substance having no heavy atom effect with a gas having a substance having a heavy atom effect. A gas that does not have a heavy atom effect can be used without particular limitation as long as it does not adversely affect the structure and light emission characteristics of the phosphorescent material. In addition, when a substance having a heavy atom effect is a liquid, a substance having a heavy atom effect may be mixed with a liquid having a substance having no heavy atom effect to adjust the concentration. As the liquid of the substance not having the heavy atom effect, a liquid that does not adversely affect the structure and light emission characteristics of the phosphorescent light emitting material and is compatible with the liquid of the substance having the heavy atom effect can be used. Examples include hexane, toluene, chloroform, and the like. Further, the liquid of the substance having a heavy atom effect may be a solution or a dispersion liquid in which a solid of a substance having a heavy atom effect is dissolved or dispersed in a solvent.

The concentration of the substance having the heavy atom effect is defined by the filling rate of the hollow region in the hollow body, and the state in which one substance having the heavy atom effect is included in one hollow region is 100% heavy atom material filling rate. As defined, the filling rate is preferably 0.01% or more, more preferably 1% or more, and even more preferably 10% or more.
When a solid, liquid, or gas substance having a heavy atom effect is used in combination with a solid, liquid, or gas substance that does not have a heavy atom effect, the substance that does not have a heavy atom effect is added to the heavy atom substance filling rate. Since there is no influence, only the filling rate of the substance having the heavy atom effect needs to be considered. The filling factor of the substance having a heavy atom effect is preferably 0.01% or more, more preferably 1% or more, and further preferably 10% or more.

<Method of emitting phosphorescence from phosphorescent emitter>
In the method of emitting phosphorescence from the phosphorescent emitter of the present invention, phosphorescence is emitted from the phosphorescent emitter at a specific temperature by encapsulating the phosphorescent emitter that does not emit phosphorescence at a specific temperature in a hollow body having a hollow region. Let
In the present invention, the specific temperature is not particularly limited, and may be room temperature, a temperature lower than room temperature, or a temperature higher than room temperature. The specific temperature can be freely selected depending on the purpose of use of the phosphorescent radiation and the usage environment. For the description and the preferred range of the phosphorescent body and the hollow body having a hollow region, the description and the preferred range in the section of [Phosphorescent body] and “Hollow body having a hollow region” can be referred to.
When the phosphorescent emitter is encapsulated in a hollow body having a hollow region, when the phosphorescent emitter transitions to the excited triplet state, vibration of the phosphorescent emitter molecule is suppressed, and radiationless deactivation such as thermal deactivation is performed. Is estimated to be suppressed. As a result, according to the method of emitting phosphorescence of the present invention, after the phosphorescent light emitter transitions to the excited triplet state even at a specific temperature where phosphorescence is not emitted in a state not encapsulated in the hollow body. The phosphorescence can be efficiently emitted and deactivated (radiation deactivation), and the phosphorescence emission can be confirmed with high intensity.

In the method of emitting phosphorescence from the phosphorescent emitter of the present invention, the phosphorescent emitter may be coexistent with a substance having a heavy atom effect in a state of being encapsulated in a hollow body having a hollow region. As a result, a substance having a heavy atom effect is taken into the hollow body, and due to the external heavy atom effect, an intersystem crossing from the excited singlet state to the excited triplet state of the phosphorescent emitter or from the excited triplet state to the ground singlet state. It is presumed that the deactivation process is accelerated, the time until the phosphorescence intensity is saturated is shortened, and the emission lifetime is shortened. Therefore, by adjusting the concentration of the substance having the heavy atom effect as appropriate and applying it, or by appropriately selecting the type and combination of the substance having the heavy atom effect to be used, the emission lifetime can be set to an arbitrary length. Can be controlled.
For the definition, preferable range, and specific examples of the substance having a heavy atom effect, the column of phosphorescent composition can be referred to. Also in this case, a substance having a heavy atom effect may be mixed with a substance having no heavy atom effect.
When a substance having a heavy atom effect is used, a phosphorescent substance in a state of being encapsulated in a hollow body may be coexisted in advance by exciting the phosphorescent substance in the substance. After the luminous body is encapsulated in the hollow body and excited, the substance may be introduced into the system to coexist.

<Method for producing phosphorescent material>
The method for producing a phosphorescent material of the present invention includes a step of encapsulating a phosphorescent material that does not emit phosphorescence at a specific temperature in a hollow body having a hollow region.
For the description and the preferred range of the phosphorescent body and the hollow body having a hollow region, the description and the preferred range in the section of [Phosphorescent body] and “Hollow body having a hollow region” can be referred to. For the explanation of the “temperature of”, reference can be made to the explanation in the above section <Method of emitting phosphorescence from phosphorescent emitter>.
The above step is preferably performed by synthesizing a hollow body so as to include a phosphorescent emitter. Even if the phosphorescent body is to be encapsulated in a pre-synthesized hollow body, the maximum width of the phosphorescent body is usually larger than the hole diameter of the outer edge of the hollow body, so that the phosphorescent body is allowed to pass through the holes of the hollow body. It cannot be taken into the hollow region, and it is difficult to encapsulate the phosphorescent emitter in the hollow body. On the other hand, according to the method of synthesizing the hollow body so as to enclose the phosphorescent light emitter, the process of passing the phosphorescent light emitter through the voids of the hollow body becomes unnecessary. Regardless of the pore size of the outer edge of the phosphor, the phosphorescent material can be successfully encapsulated in a hollow body to produce a phosphorescent material.

In order to synthesize a hollow body so as to include a phosphorescent material, a raw material compound corresponding to the repeating unit of the hollow body (for example, “organic ligand” and “metal salt” in the case of a metal organic structure) and a phosphorescent material In the state where coexisting, the raw material compounds are continuously bonded by reaction. As a result, a repeating unit derived from the raw material compound is assembled so as to surround the phosphorescent light emitter, so that a hollow body grows, and a phosphorescent light emitting material in which the hollow body includes the phosphorescent light emitter is obtained.
Here, when the reaction between the raw material compounds is performed by heating, it is preferable to select a phosphorescent material having heat resistance that can withstand the heating temperature. For example, ZIF-8 is synthesized by heating methylimidazole and a zinc compound to about 140 ° C. For this reason, it is preferable to use a compound having heat resistance in the vicinity of this temperature for the phosphorescent emitter encapsulated in ZIF-8. Specifically, since the compound is easily decomposed when it has a functional group, it is preferable to select a phosphorescent material in which the skeleton structure is not substituted with a functional group or the number of functional group substitutions is small.
In addition, regarding the ratio of the raw material compound and phosphorescent emitter coexisting in the reaction system, if the ratio of the phosphorescent emitter is too high, there is a possibility that the phosphorescent emitters are associated with each other in the form of phosphorescence. It is preferable to set the ratio of the light emitters to a certain level. For example, in a synthetic reaction system of a metal organic structure using imidazole or a derivative thereof as an organic ligand, the molar ratio of the phosphorescent emitter to the metal compound is preferably 1: 1 to 1: 1000, and 1:10 It is more preferable to set to ˜1: 100, and it is more preferable to set to 1:20 to 1:50.

<Organic light emitting device>
The phosphorescent material and the phosphorescent composition of the present invention are useful as a material for a light emitting layer of an organic light emitting device. The phosphorescent light emitting material and phosphorescent light emitting composition of the present invention are such that a hollow body having a hollow region encapsulates the phosphorescent light emitting material, so that the phosphorescent light emitter excited in the excited triplet state is non-radiatively lost even at room temperature. It is difficult to activate and emits phosphorescence efficiently through radiation deactivation. Therefore, high luminous efficiency can be obtained at room temperature by using the phosphorescent material of the present invention as a material of the light emitting layer of the organic light emitting element.
For example, an organic electroluminescent element that injects carriers into a light emitting layer to excite a light emitter will be described as an example. In an organic electroluminescent element, 25% of the light emitting material is excited to an excited singlet state. And the remaining 75% is excited to the excited triplet state. Here, in the configuration using the fluorescent light emitter that emits fluorescence from the excited singlet state and returns to the ground state, the energy of the excited triplet state that occupies 75% of the whole cannot be effectively used for light emission. On the other hand, since the phosphorescent light emitter transitions from an excited singlet state to an excited triplet state through intersystem crossing, in principle, an excited triplet state is generated at a rate exceeding 75%. However, even if a normal phosphorescent material transitions to an excited triplet state, it tends to lose energy due to thermal deactivation or the like at room temperature, and consequently, the excited triplet energy cannot be effectively used for light emission. In contrast, in the phosphorescent material of the present invention, as described above, the non-radiative deactivation of the excited triplet state can be suppressed even at room temperature, so that the excited triplet state phosphorescent phosphor is efficiently phosphorescent. The excited triplet state energy can be effectively used for light emission. For this reason, according to the phosphorescent light-emitting material of the present invention, it is possible to obtain much higher light emission efficiency than when a fluorescent light-emitting material or a conventional phosphorescent light-emitting material is used.

As described above, by using the phosphorescent material and the phosphorescent composition of the present invention, an excellent organic light-emitting device such as an organic photoluminescence device (organic PL device) or an organic electroluminescence device (organic EL device) is provided. Can do. The organic photoluminescence element has a structure in which at least a light emitting layer is formed on a substrate. The organic electroluminescence element has a structure in which an organic layer is formed at least between an anode, a cathode, and an anode and a cathode. The organic layer includes at least a light emitting layer, and may consist of only the light emitting layer, or may have one or more organic layers in addition to the light emitting layer. Examples of such other organic layers include a hole transport layer, a hole injection layer, an electron blocking layer, a hole blocking layer, an electron injection layer, an electron transport layer, and an exciton blocking layer. The hole transport layer may be a hole injection / transport layer having a hole injection function, and the electron transport layer may be an electron injection / transport layer having an electron injection function. A specific example of the structure of an organic electroluminescence element is shown in FIG. In FIG. 1, 1 is a substrate, 2 is an anode, 3 is a hole injection layer, 4 is a hole transport layer, 5 is a light emitting layer, 6 is an electron transport layer, and 7 is a cathode.
Below, each member and each layer of an organic electroluminescent element are demonstrated. In addition, description of a board | substrate and a light emitting layer corresponds also to the board | substrate and light emitting layer of an organic photo-luminescence element.

[substrate]
The organic electroluminescence device of the present invention is preferably supported on a substrate. The substrate is not particularly limited and may be any substrate that has been conventionally used in organic electroluminescence elements. For example, a substrate made of glass, transparent plastic, quartz, silicon, or the like can be used.

[anode]
As the anode in the organic electroluminescence element, an electrode material made of a metal, an alloy, an electrically conductive compound, or a mixture thereof having a high work function (4 eV or more) is preferably used. Specific examples of such electrode materials include metals such as Au, and conductive transparent materials such as CuI, indium tin oxide (ITO), SnO ₂ and ZnO. Alternatively, an amorphous material such as IDIXO (In ₂ O ₃ —ZnO) capable of forming a transparent conductive film may be used. For the anode, a thin film may be formed by vapor deposition or sputtering of these electrode materials, and a pattern of a desired shape may be formed by photolithography, or when pattern accuracy is not so high (about 100 μm or more) ), A pattern may be formed through a mask having a desired shape at the time of vapor deposition or sputtering of the electrode material. Or when using the material which can be apply | coated like an organic electroconductivity compound, wet film-forming methods, such as a printing system and a coating system, can also be used. When light emission is extracted from the anode, it is desirable that the transmittance be greater than 10%, and the sheet resistance as the anode is preferably several hundred Ω / □ or less. Further, although the film thickness depends on the material, it is usually selected in the range of 10 to 1000 nm, preferably 10 to 200 nm.

[cathode]
On the other hand, as the cathode, a material having a low work function (4 eV or less) metal (referred to as an electron injecting metal), an alloy, an electrically conductive compound, and a mixture thereof as an electrode material is used. Specific examples of such electrode materials include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al ₂ O ₃ ) Mixtures, indium, lithium / aluminum mixtures, rare earth metals and the like. Among these, from the point of durability against electron injection and oxidation, a mixture of an electron injecting metal and a second metal which is a stable metal having a larger work function value than this, for example, a magnesium / silver mixture, Magnesium / aluminum mixtures, magnesium / indium mixtures, aluminum / aluminum oxide (Al ₂ O ₃ ) mixtures, lithium / aluminum mixtures, aluminum and the like are preferred. The cathode can be produced by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering. The sheet resistance as the cathode is preferably several hundred Ω / □ or less, and the film thickness is usually selected in the range of 10 nm to 5 μm, preferably 50 to 200 nm. In order to transmit the emitted light, if either one of the anode or the cathode of the organic electroluminescence element is transparent or translucent, the emission luminance is advantageously improved.
In addition, by using the conductive transparent material mentioned in the description of the anode as a cathode, a transparent or semi-transparent cathode can be produced. By applying this, an element in which both the anode and the cathode are transparent is used. Can be produced.

[Light emitting layer]
The light emitting layer is a layer that emits light after excitons are generated by recombination of holes and electrons injected from the anode and the cathode, respectively. In the organic electroluminescence device of the present invention, the light emitting layer includes the phosphorescent material of the present invention. For the description and preferred range of the phosphorescent material, the contents of the <phosphorescent material> column can be referred to.
In the organic electroluminescence device of the present invention, light emission is generated from the phosphorescent material of the phosphorescent material of the present invention contained in the light emitting layer. This emission is mainly phosphorescence emission, but may include fluorescence emission and delayed fluorescence emission. Further, a part of the light emission may be light emission from the host material.

[Injection layer]
The injection layer is a layer provided between the electrode and the organic layer for lowering the driving voltage and improving the luminance of light emission, and includes a hole injection layer and an electron injection layer, Further, it may be present between the cathode and the light emitting layer or the electron transport layer. The injection layer can be provided as necessary.

[Blocking layer]
The blocking layer is a layer that can prevent diffusion of charges (electrons or holes) and / or excitons existing in the light emitting layer to the outside of the light emitting layer. The electron blocking layer can be disposed between the light emitting layer and the hole transport layer and blocks electrons from passing through the light emitting layer toward the hole transport layer. Similarly, a hole blocking layer can be disposed between the light emitting layer and the electron transporting layer to prevent holes from passing through the light emitting layer toward the electron transporting layer. The blocking layer can also be used to block excitons from diffusing outside the light emitting layer. That is, each of the electron blocking layer and the hole blocking layer can also function as an exciton blocking layer. The term “electron blocking layer” or “exciton blocking layer” as used herein is used in the sense of including a layer having the functions of an electron blocking layer and an exciton blocking layer in one layer.

[Hole blocking layer]
The hole blocking layer has a function of an electron transport layer in a broad sense. The hole blocking layer has a role of blocking holes from reaching the electron transport layer while transporting electrons, thereby improving the recombination probability of electrons and holes in the light emitting layer. As the material for the hole blocking layer, the material for the electron transport layer described later can be used as necessary.

[Electron blocking layer]
The electron blocking layer has a function of transporting holes in a broad sense. The electron blocking layer has a role to block electrons from reaching the hole transport layer while transporting holes, thereby improving the probability of recombination of electrons and holes in the light emitting layer. .

[Exciton blocking layer]
The exciton blocking layer is a layer for preventing excitons generated by recombination of holes and electrons in the light emitting layer from diffusing into the charge transport layer. It becomes possible to efficiently confine in the light emitting layer, and the light emission efficiency of the device can be improved. The exciton blocking layer can be inserted on either the anode side or the cathode side adjacent to the light emitting layer, or both can be inserted simultaneously. That is, when the exciton blocking layer is provided on the anode side, the layer can be inserted adjacent to the light emitting layer between the hole transport layer and the light emitting layer, and when inserted on the cathode side, the light emitting layer and the cathode Between the luminescent layer and the light-emitting layer. Further, a hole injection layer, an electron blocking layer, or the like can be provided between the anode and the exciton blocking layer adjacent to the anode side of the light emitting layer, and the excitation adjacent to the cathode and the cathode side of the light emitting layer can be provided. Between the child blocking layer, an electron injection layer, an electron transport layer, a hole blocking layer, and the like can be provided. When the blocking layer is disposed, at least one of the excited singlet energy and the excited triplet energy of the material used as the blocking layer is preferably higher than the excited singlet energy and the excited triplet energy of the light emitting material.

[Hole transport layer]
The hole transport layer is made of a hole transport material having a function of transporting holes, and the hole transport layer can be provided as a single layer or a plurality of layers.
The hole transport material has any one of hole injection or transport and electron barrier properties, and may be either organic or inorganic. Known hole transport materials that can be used include, for example, triazole derivatives, oxadiazole derivatives, imidazole derivatives, carbazole derivatives, indolocarbazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, Examples include amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aniline copolymers, and conductive polymer oligomers, particularly thiophene oligomers. An aromatic tertiary amine compound and an styrylamine compound are preferably used, and an aromatic tertiary amine compound is more preferably used.

[Electron transport layer]
The electron transport layer is made of a material having a function of transporting electrons, and the electron transport layer can be provided as a single layer or a plurality of layers.
The electron transport material (which may also serve as a hole blocking material) may have a function of transmitting electrons injected from the cathode to the light emitting layer. Examples of the electron transport layer that can be used include nitro-substituted fluorene derivatives, diphenylquinone derivatives, thiopyran dioxide oxide derivatives, carbodiimides, fluorenylidenemethane derivatives, anthraquinodimethane and anthrone derivatives, oxadiazole derivatives, and the like. Furthermore, in the above oxadiazole derivative, a thiadiazole derivative in which the oxygen atom of the oxadiazole ring is substituted with a sulfur atom, and a quinoxaline derivative having a quinoxaline ring known as an electron withdrawing group can also be used as an electron transport material. Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used.

  The method for forming the light-emitting layer, injection layer, blocking layer, hole blocking layer, electron blocking layer, exciton blocking layer, hole transport layer, and electron transport layer is not particularly limited, and either dry process or wet process is used. You may produce by.

Below, the preferable material which can be used for an organic electroluminescent element is illustrated concretely. However, the material that can be used in the present invention is not limited to the following exemplary compounds. Moreover, even if it is a compound illustrated as a material which has a specific function, it can also be diverted as a material which has another function. In addition, R, R ′, and R _{1 to} R ₁₀ in the structural formulas of the following exemplary compounds each independently represent a hydrogen atom or a substituent. X represents a carbon atom or a hetero atom forming a ring skeleton, n represents an integer of 3 to 5, Y represents a substituent, and m represents an integer of 0 or more.

  First, examples of preferable compounds that can be used as a hole injection material are given.

  Next, examples of preferred compounds that can be used as a hole transport material are listed.

  Next, examples of preferable compounds that can be used as an electron blocking material are given.

  Next, preferred compound examples that can be used as a hole blocking material are listed.

  Next, examples of preferable compounds that can be used as an electron transporting material will be given.

  Next, examples of preferable compounds that can be used as the electron injection material are given.

  Furthermore, preferable compound examples are given as materials that can be added. For example, adding as a stabilizing material can be considered.

[Driving method]
The organic electroluminescent element of the present invention emits light by applying a current to the light emitting layer through the positive electrode and the negative electrode. This light emission is presumed to be caused by the following mechanism.
That is, when a current is applied by the positive electrode and the negative electrode, holes are injected into the light emitting layer from the anode side, electrons are injected from the cathode side, and the holes and electrons are hollow and phosphorescent emitters having a hollow region. Energy is generated by recombination above. This energy excites the phosphorescent emitter into an excited singlet state and an excited triplet state. At least a part of the phosphorescent material excited to the excited singlet state transitions to the excited triplet state through intersystem crossing. Here, the phosphorescent emitter in the excited triplet state has a long lifetime because the excited triplet state and the ground state are in a spin-forbidden relationship and is difficult to return to the ground state. Since vibration is suppressed by being included in the hollow body, thermal deactivation (nonradiative deactivation) while in the excited triplet state is suppressed. Therefore, the excited triplet state phosphorescent emitter efficiently returns to the ground state while emitting phosphorescence. For this reason, this organic electroluminescent element can obtain high luminous efficiency.

  The organic electroluminescence element of the present invention can be applied to any of a single element, an element having a structure arranged in an array, and a structure in which an anode and a cathode are arranged in an XY matrix. The organic light emitting device such as the organic electroluminescence device of the present invention can be further applied to various uses. For example, it is possible to produce an organic electroluminescence display device using the organic electroluminescence element of the present invention. For details, see “Organic EL Display” (Ohm Co., Ltd.) written by Shizushi Tokito, Chiba Adachi and Hideyuki Murata. ) Can be referred to. In particular, the organic electroluminescence device of the present invention can be applied to organic electroluminescence illumination and backlights that are in great demand.

<Gas sensor>
The phosphorescent light-emitting material of the present invention can be suitably used as a material for a sensitive part of a gas sensor, in addition to a material for a light-emitting layer of an organic light-emitting element. In the gas sensor using the phosphorescent material of the present invention as the material of the sensitive part, when the gas is adsorbed to the hollow body, the light emission performance of the phosphorescent body changes depending on the type and concentration of the gas. Thereby, the kind and density | concentration of the gas of the environment where the gas sensor is placed can be detected. An organometallic structure can be preferably used for the hollow body of the phosphorescent material used in the gas sensor because of its high gas adsorbing ability. Moreover, it is preferable to use a phosphorescent light emitter whose light emission performance is remarkably changed by contact with a specific gas. For example, coronene can be suitably used as a phosphorescent material of a phosphorescent material for oxygen detection because light emission is not observed when oxygen is incorporated.

  The features of the present invention will be described more specifically with reference to synthesis examples and examples. The following materials, processing details, processing procedures, and the like can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples shown below. In addition, evaluation of the light emission characteristics is performed by X-ray diffraction analyzer (Ulyima IV manufactured by Rigaku Corporation), high performance ultraviolet visible near infrared spectrophotometer (Perkin Elmer: Lambda 950), fluorescence spectrophotometer (manufactured by Horiba: FluoroMax- 4) Absolute PL quantum yield measurement device (Hamamatsu Photonics C11347), source meter (Keithley 2400 series), semiconductor parameter analyzer (Agilent Technology E5273A), optical power meter measurement ( Newport: 1930C), optical spectrometer (Ocean Optics: USB2000), spectroradiometer (Topcon: SR-3) and multichannel spectrometer (Hamamatsu Photonics PMA-50) I went.

Example 1 Synthesis of phosphorescent material in which ZIF-8 includes compound 34 (coronene) Zn (NO ₃ ) ₂ .6H ₂ O (0.597 g, 2.01 mmol), 2-methylimidazole (0 150 g, 1.83 mmol) and compound 34 (0.019 g, 6.28 × 10 ⁻² mmol) were dissolved in N, N-dimethylformamide (45 mL) to obtain a mixture. The mixture was heated to 140 ° C. at 5 ° C./min, and maintained at 140 ° C. for 24 hours. The reaction solution was cooled to room temperature at 0.4 ° C./min, and the precipitate was collected by filtration and washed with chloroform and N, N-dimethylformamide. Through the above-described steps, a phosphorescent material powder was obtained.

Example 2 Synthesis of Phosphorescent Material in which ZIF-8 Encapsulates D Substitute of Compound 34 (Coronene) In place of Compound 34, 12 hydrogen atoms of Compound 34 are substituted with deuterium D A phosphorescent material powder was obtained in the same manner as in Example 1 except that the substitution product was used.

(Example 3) Production of phosphorescent thin film in which ZIF-8 encapsulates compound 34 (coronene) Zn (NO ₃ ) ₂ .6H ₂ O (0.597 g, 2.01 mmol), 2-methylimidazole (0.150 g , 1.83 mmol), Compound 34 (0.019 g, 6.28 × 10 ⁻² mmol) was dissolved in N, N-dimethylformamide (45 mL) to prepare a mixture. In this mixture, a glass substrate with an ITO (Indium Tin Oxide) film surface-treated with 3-aminopropyltrimethoxysilane was immersed, and then the temperature was raised to 140 ° C. at 5 ° C./min. Maintained for hours. The reaction solution was cooled to room temperature at 0.4 ° C./min, and then the substrate was washed with chloroform and N, N-dimethylformamide. A phosphorescent thin film was prepared by the above process.

Example 4 Fabrication of Thin Film of Phosphorescent Light-Emitting Material in which ZIF-8 Encloses D-Substituted Compound 34 (Coronene) D Instead of Compound 34, 12 Hydrogen Atoms of Compound 34 were Replaced with Deuterium D A phosphorescent thin film was obtained in the same manner as in Example 3 except that the substitution product was used.

(Example 5) Synthesis of phosphorescent material in which ZIF-8 encapsulates compound 37 Zn (NO ₃ ) ₂ .6H ₂ O (0.597 g, 2.01 mmol), 2-methylimidazole (0.150 g, 1.83 mmol) and compound 37 (0.018 g, 6.28 × 10 ⁻² mmol) were dissolved in N, N-dimethylformamide (45 mL) to obtain a mixture. The mixture was heated to 140 ° C. at 5 ° C./min, and maintained at 140 ° C. for 24 hours. The reaction solution was cooled to room temperature at 0.4 ° C./min, and the precipitate was collected by filtration and washed with chloroform and N, N-dimethylformamide. Through the above-described steps, a phosphorescent material powder was obtained.

(Comparative Example 1) Synthesis of ZIF-8 ZIF-8 powder was obtained in the same manner as in Example 1 except that Compound 34 was not added to the mixture.

Comparative Example 2 Preparation of Compound 34 (Coronene) in dichloromethane and solution Compound 34 was dissolved in dichloromethane and 2-methyltetrahydrofuran at a concentration of 0.01 mM to prepare a solution. The 2-methyltetrahydrofuran solution was cooled to -77K using liquid nitrogen.

Comparative Example 3 Preparation of Polymethyl Methacrylate (PMMA) Thin Film Containing Compound 34 (Coronene) Compound 34 (0.019 g, 6.28 × 10 ⁻² mmol) and PMMA (2.20 g) were added to N, N— A mixture was prepared by dissolving in dimethylformamide (45 mL). This mixture was formed into a film on a quartz substrate by a spin coat method (1000 rpm, 60 seconds) to obtain a PMMA thin film containing compound 34.

[1] X-ray diffraction analysis and evaluation of emission characteristics FIG. 3 shows X-ray diffraction spectra observed for the phosphorescent material powders of Example 1 and Example 2 and the ZIF-8 powder of Comparative Example 1. FIG. 4 shows the fluorescence spectrum and phosphorescence spectrum of the phosphorescent light-emitting thin film of Example 3 and the solution of Comparative Example 2 by 340 nm excitation light. Moreover, the 560-nm emission intensity transient attenuation | damping curve in the 340-nm excitation light of the thin film of Example 3, Example 4, and the comparative example 3 is shown in FIG. The light emission characteristics shown in FIGS. 4 and 5 are measured under the condition of 25 ° C. FIG. 6 shows the temperature dependence of the emission lifetime in the thin film 340 nm excitation light of Example 3, Example 4, and Comparative Example 3. The phosphorescence spectrum of the powder of Example 5 is shown in FIG. Moreover, the 560-nm emission intensity transient decay curve in the 340-nm excitation light of the powder of Example 5 is shown in FIG.
In the fluorescence spectrum of FIG. 4, no light emission derived from excimer was observed in the thin film of Example 3, which was in agreement with the solution state spectrum of Comparative Example 2, and thus the phosphorescent material produced was per unit cell of ZIF-8. It was confirmed that one molecule of compound 34 was encapsulated and compound 34 was in a completely dispersed state.
Further, from FIG. 5, a phosphorescent thin film (Example 3) in which the compound 34 is encapsulated in ZIF-8 and a phosphorescent thin film (Example 4) in which the D substitution product of the compound 34 is encapsulated in ZIF-8. It was possible to confirm phosphorescence emission at room temperature. The phosphorescence lifetime of the phosphorescent light emitting material of Example 3 obtained from FIG. 5 is 8.8 seconds, the phosphorescence lifetime of the phosphorescent light emitting material of Example 4 is 22.4 seconds, and both phosphorescent light emitting materials are long. Lifetime phosphorescence emission could be observed. In addition, it was confirmed from FIG. 6 that the phosphorescent materials of Example 3 and Example 4 have long-life luminescence even at 460K. On the other hand, in the thin film of Comparative Example 3, no phosphorescence was observed at 320 K or higher. From FIG. 7, it was confirmed that the material in which the benzene rings flip in the solution also has long-lived phosphorescence. From FIG. 8, the phosphorescence lifetime of the phosphorescent material of Example 5 was 0.8 seconds.

[2] Examination of effect by introduction of Xe gas The fluorescence spectrum and phosphorescence spectrum of Compound 34 (Coronene) measured in a reduced pressure atmosphere of 10 ⁻³ Pa are shown in FIG. 9 (a), and 10 ⁵ Pa of 100% Xe FIG. 9 (b) shows the fluorescence spectrum and phosphorescence spectrum measured in the gas, and FIG. 9 (c) shows the fluorescence spectrum and phosphorescence spectrum measured in the atmosphere.
From comparison between (a) and (b) of FIG. 9, when compound 34 is placed in Xe gas, phosphorescence emission at 563 nm is hardly observed in the absence of Xe gas (depressurized state of 10 ⁻³ Pa). It can be seen that phosphorescence of 518 nm appears.

Next, with respect to the powder of the phosphorescent material of Example 1 placed in a reduced pressure atmosphere of 10 ⁻³ Pa, the emission intensity when 100% Xe gas was introduced into the atmosphere after 6 seconds had passed after irradiating excitation light of 340 nm A transient attenuation curve is shown in FIG. Also shown is a light emission intensity transient decay curve measured without introducing Xe gas after irradiating the phosphor of the phosphorescent material of Example 1 placed in a reduced pressure state of 10 ⁻³ Pa with excitation light. The measurement of the light emission characteristics shown in FIG. 10 was carried out under conditions of 25 ° C. for both 518 nm and 563 nm phosphorescence.
Looking at the emission intensity excessive decay curve of FIG. 10, it can be seen that the emission intensity at 518 nm and 563 nm both rises to a peak immediately after introducing Xe gas into the phosphorescent material, and then decays rapidly. . The increase in peak emission intensity is presumed to be due to the rapid accumulation of triplet excitons due to the accelerated intersystem crossing from the excited singlet state to the excited triplet state by the introduction of Xe gas. In addition, the rapid decay of the emission intensity is presumed to be due to the accelerated deactivation process from the excited triplet state to the ground singlet state. From these facts, it was found that Xe gas has the effect of accelerating intersystem crossing and deactivation process, and has the effect of increasing the light emission amount of the phosphorescent material and shortening the lifetime. From this, it was found that the emission lifetime can be effectively controlled by adjusting the Xe concentration of the atmosphere in which the phosphorescent material is placed.

[3] Examination of effect by mixing with dibromomethane (CH ₂ Br ₂ ) The phosphorescent material synthesized in Example 1 was put in degassed dibromomethane and stirred for 1 minute to prepare a mixture. The concentration of the phosphorescent material in the mixture was 1.5% by mass, and the concentration of CH ₂ Br ₂ was 100% heavy atom substance filling rate. With respect to the prepared mixture, an emission intensity transient decay curve of 563 nm phosphorescence in 340 nm excitation light was measured at 300K. The result is shown in FIG. Further, FIG. 11 shows a luminescence intensity transient decay curve obtained by measuring the phosphorescent material powder synthesized in Example 1 in a reduced pressure state of 10 ⁻³ Pa.
The time until the phosphorescence intensity determined from FIG. 11 was saturated was 5 seconds for the phosphorescent material mixed with dibromomethane and 25 seconds for the phosphorescent material not mixed with dibromomethane. Moreover, the phosphorescence lifetime calculated | required from FIG. 13 was 0.6 second with the phosphorescence material which mixed the dibromomethane, and was 7.4 seconds with the phosphorescence material which did not mix the dibromomethane. From these facts, it was found that a halide such as dibromomethane has an effect of shortening the phosphorescence lifetime of the phosphorescent material and shortening the phosphorescence lifetime.

  Since the phosphorescent material of the present invention can confirm phosphorescence having a high emission intensity at room temperature while using a phosphorescent material that does not emit phosphorescence at 25 ° C., it can be used as a material for a light emitting layer of an organic light emitting device. It can be used suitably. For this reason, this invention has high industrial applicability.

DESCRIPTION OF SYMBOLS 1 Substrate 2 Anode 3 Hole injection layer 4 Hole transport layer 5 Light emitting layer 6 Electron transport layer 7 Cathode 11 Zeolite imidazolate structure (hollow body having hollow region)
12 Phosphorescent emitter 13 Hole

Claims (30)

  A hollow body having a hollow region is a phosphorescent material including a phosphorescent emitter, and phosphorescence from the phosphorescent emitter at 25 ° C. is not in the state where the phosphorescent emitter is not included in the hollow body. A phosphorescent material that is not recognized and is recognized when the phosphorescent body is encapsulated in the hollow body.   2. The phosphorescent material according to claim 1, wherein the hollow region has a space in which one or more molecules of the phosphorescent body can be encapsulated.   The phosphorescent material according to claim 1 or 2, wherein the hollow body having the hollow region is an organometallic structure.   The phosphorescent material according to claim 3, wherein the organometallic structure is a zeolite imidazolate structure.   The phosphorescent material according to claim 3 or 4, wherein the metal ions of the organometallic structure are zinc ions.   The phosphorescent material according to any one of claims 1 to 5, wherein the phosphorescent emitter does not contain a metal atom.   The phosphorescent material according to claim 1, wherein the phosphorescent emitter is a π-conjugated planar molecule.   The phosphorescent light-emitting material according to claim 7, wherein the π-conjugated planar molecule has a condensed polycyclic structure in which two or more benzene rings are condensed.   The phosphorescent material according to claim 8, wherein the condensed polycyclic structure is a condensed polycyclic skeleton structure having a rotationally symmetric axis. The phosphorescent light-emitting material according to claim 9, wherein the π-conjugated planar molecule is a D-substitution in which part or all of hydrogen atoms of coronene or coronene are substituted with ² H (deuterium D). . The phosphorescent material according to claim 8, wherein the π-conjugated planar molecule has a condensed polycyclic structure represented by the following formula.
  The phosphorescent light-emitting material according to claim 8, wherein the condensed polycyclic structure does not have a substituent.   A phosphorescent composition comprising the phosphorescent material according to claim 1 and a substance having a heavy atom effect.   The phosphorescent composition according to claim 13, wherein the substance having a heavy atom effect is a gas or a liquid.   The phosphorescent composition according to claim 13 or 14, wherein the substance having a heavy atom effect is a gas and further contains a gas of a substance not having a heavy atom effect.   The phosphorescent composition according to claim 13 or 14, wherein the substance having a heavy atom effect is a liquid, and further includes a liquid of a substance having no heavy atom effect.   The phosphorescent composition according to claim 13 or 14, comprising a solution in which the substance having the heavy atom effect is dissolved in a solvent.   18. The substance having a heavy atom effect is at least one selected from a group 18 element, a compound containing a group 17 element, a compound containing a group 16 element, and a metal complex. The phosphorescent composition according to item.   The phosphorescent composition according to claim 18, wherein the substance having a heavy atom effect is Xe gas.   The phosphorescent composition according to claim 18, wherein the substance having a heavy atom effect is a halogenated alkane.   A method of emitting phosphorescence from the phosphorescent emitter at the specific temperature by encapsulating a phosphorescent emitter that does not emit phosphorescence at a specific temperature in a hollow body having a hollow region.   A phosphorescent emitter that does not emit phosphorescence at a specific temperature coexists with a substance having a heavy atom effect in a state of being included in a hollow body having a hollow region, and phosphorescence is emitted from the phosphorescent emitter at the specific temperature. Item 22. The method according to Item 21.   A method for producing a phosphorescent material, comprising a step of encapsulating a phosphorescent material that does not emit phosphorescence at a specific temperature in a hollow body having a hollow region.   The method for producing a phosphorescent material according to claim 23, wherein the step is performed by synthesizing the hollow body so as to include the phosphorescent body. The hollow body is a metal organic structure,
25. The phosphorescence emission according to claim 24, wherein the step is performed by coordinating the organic ligand and a metal ion of the metal salt in a mixture containing an organic ligand, a metal salt and the phosphorescent emitter. Material manufacturing method.   An organic light-emitting device comprising the phosphorescent material according to claim 1.   An organic light emitting device comprising the phosphorescent composition according to any one of claims 13 to 20.   The organic light-emitting device according to claim 26, wherein the organic light-emitting device is an organic electroluminescence device.   29. The organic light-emitting device according to claim 17, wherein phosphorescence is observed at room temperature.   A gas sensor comprising the phosphorescent material according to claim 1.