Polycyclic aromatic compound, color conversion composition, color conversion sheet, light source unit, display and lighting device

Abstract

The polycyclic aromatic compound according to one embodiment of the present invention is a compound which, when subjected to excitation light, emits observable light, exhibits a peak wavelength region between 500 nm and 750 nm where the HOMO level is -5.7 eV or less, and emits delayed fluorescence.

Description

Polycyclic aromatic compound, color-converting composition, color-converting sheet, light source unit, display, and lighting device

[0001] The present invention relates to a polycyclic aromatic compound, a color-converting composition, a color-converting sheet, a light source unit, a display, and a lighting device.

[0002] The application of multi-color technology using color conversion methods to liquid crystal displays, organic EL displays, lighting devices, etc. Color conversion refers to converting the light emitted from an illuminant into light with a longer wavelength, for example, converting blue light into green or red light.

[0003] By forming this composition having color conversion function (hereinafter referred to as "color conversion composition") into a sheet and combining it with, for example, a blue light source, it becomes possible to extract the three primary colors of blue, green, and red from the blue light source, i.e., to extract white light. A white light source combining such a blue light source with a sheet having color conversion function (hereinafter referred to as "color conversion sheet") is used as a light source unit, and by combining this light source unit with a liquid crystal driving part and a color filter, it becomes possible to produce a full-color display. Furthermore, if there is no liquid crystal driving part, it can be used as a white light source as is, and can be applied as a white light source for, for example, LED lighting.

[0004] One of the challenges facing liquid crystal displays is improving color reproducibility. To improve color reproducibility, it is effective to narrow the half-widths of the blue, green, and red emission spectra of the light source unit and increase the color purity of each of the blue, green, and red colors. To solve this problem, a technology has been proposed in which quantum dots made of inorganic semiconductor fine particles are used as components of a color-converting composition (see, for example, Patent Document 1). While this technology using quantum dots does indeed narrow the half-widths of the green and red emission spectra and improve color reproducibility, quantum dots are vulnerable to heat and moisture and oxygen in the air, and therefore have insufficient durability.

[0005] Furthermore, a technique has been proposed in which an organic light-emitting material is used as a component of a color-changing composition instead of quantum dots. Examples of the technique using an organic light-emitting material as a component of a color-changing composition include those using pyrromethene derivatives (see, for example, Patent Documents 1 and 2).

[0006] JP 2011-241160 A JP 2014-136771 A

[0007] However, even if these organic light-emitting materials are used to prepare color-converting compositions, the results are still insufficient in terms of improving color reproducibility and durability. In particular, there is a lack of technology that can achieve both high color purity green light emission and high durability.

[0008] The problem to be solved by the present invention is to provide an organic light-emitting material suitable as a color conversion material used in displays such as liquid crystal displays and lighting devices such as LED lighting, which material has both improved color reproducibility and high durability.

[0009] That is, in order to solve the above-mentioned problems and achieve the object, the polycyclic aromatic compound according to the present invention is characterized in that it is a compound that, when using excitation light, exhibits luminescence whose peak wavelength is observed in a region of 500 nm or more and 750 nm or less, has a HOMO level of −5.7 eV or less, and emits delayed fluorescence.

[0010] Furthermore, the polycyclic aromatic compound according to the present invention is characterized in that, in the above invention, the HOMO level of the polycyclic aromatic compound is −6.0 eV or less.

[0011] Furthermore, the polycyclic aromatic compound according to the present invention is characterized in that, in the above invention, the HOMO level of the polycyclic aromatic compound is −6.2 eV or less.

[0012] Furthermore, the polycyclic aromatic compound according to the present invention is characterized in that, in the above invention, the HOMO level of the polycyclic aromatic compound is −6.5 eV or less.

[0013] Furthermore, the polycyclic aromatic compound according to the present invention is characterized in that, in the above invention, the half width of the emission spectrum at the emission peak wavelength of the polycyclic aromatic compound is 40 nm or less.

[0014] Furthermore, the polycyclic aromatic compound according to the present invention is characterized in that, in the above invention, the polycyclic aromatic compound is a compound represented by general formula (1) or general formula (2).

[0015] (Ring Za, ring Zb, and ring Zc are each independently a substituted or unsubstituted aryl ring having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroaryl ring having 6 to 30 ring carbon atoms. Z 1 and Z 2 are each independently an oxygen atom, NRa (a nitrogen atom having a substituent Ra), or a sulfur atom. 1 When R is NRa, the substituent R may be bonded to the ring Za or the ring Zb to form a ring. 2 When R is NRa, the substituent R may be bonded to the ring Z or the ring Zc to form a ring. E is a boron atom, a phosphorus atom, SiRa (a silicon atom having a substituent R) or P=O. E 1 and E 2 are each independently BRa (boron atom having a substituent Ra), PRa (phosphorus atom having a substituent Ra), SiRa2 (silicon atom having two substituents Ra), P(=O)Ra2 (phosphine oxide having two substituents Ra) or P(=S)Ra2 (phosphine sulfide having two substituents Ra), S(=O) or S(=O)2. E 1 When is BRa, PRa, SiRa2, P(=O)Ra2 or P(=S)Ra2, the substituent Ra may be bonded to ring Za or ring Zb to form a ring. 2 is BRa, PRa, SiRa2, P(=O)Ra2, or P(=S)Ra2, the substituent Ra may be bonded to ring Za or ring Zc to form a ring. The substituents Ra are each independently a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, or a substituted or unsubstituted alkyl group.

[0016] Furthermore, the polycyclic aromatic compound according to the present invention is characterized in that, in the above invention, the compound represented by the general formula (1) or the general formula (2) has at least one electron-withdrawing group.

[0017] Furthermore, the polycyclic aromatic compound according to the present invention is characterized in that, in the above invention, the compound represented by the general formula (1) or the general formula (2) has two or more electron-withdrawing groups.

[0018] Furthermore, the polycyclic aromatic compound according to the present invention is characterized in that, in the above invention, the electron-withdrawing group is a cyano group, an acyl group, an ester group, an amide group, a sulfonyl group, a sulfonate ester group, or a sulfonamide group.

[0019] Furthermore, the polycyclic aromatic compound according to the present invention is characterized in that, in the above invention, the electron-withdrawing group is an ester group.

[0020] Further, the polycyclic aromatic compound according to the present invention is the above-mentioned polycyclic aromatic compound, 1 and Z 2 is an oxygen atom or NRa.

[0021] Furthermore, in the polycyclic aromatic compound according to the present invention, in the above invention, the E is a boron atom, and the E 1 and the above E 2 is BRa.

[0022] Furthermore, the polycyclic aromatic compound according to the present invention is characterized in that, in the above invention, the ring Za, the ring Zb, and the ring Zc are benzene rings.

[0023] Furthermore, the polycyclic aromatic compound according to the present invention is characterized in that, in the above invention, the polycyclic aromatic compound exhibits luminescence with a peak wavelength observed in a region of 500 nm or more and less than 580 nm when excited with excitation light.

[0024] Furthermore, the polycyclic aromatic compound according to the present invention is characterized in that, in the above invention, the polycyclic aromatic compound exhibits luminescence with a peak wavelength observed in the region of 580 nm or more and 750 nm or less when excited with excitation light.

[0025] Furthermore, the color-converting composition according to the present invention is a color-converting composition that converts incident light into light different from the incident light, and is characterized by comprising any one of the polycyclic aromatic compounds described above and a binder resin.

[0026] Furthermore, the color conversion sheet according to the present invention is a color conversion sheet that converts incident light into light different from the incident light, and is characterized by comprising any one of the polycyclic aromatic compounds described above and a binder resin.

[0027] Furthermore, the color conversion sheet according to the present invention is characterized in that, in the above invention, it further comprises a barrier film.

[0028] A light source unit according to the present invention is characterized by comprising a light source and any one of the color conversion sheets described above.

[0029] Furthermore, in the light source unit according to the present invention, the light source is a light emitting diode having a maximum light emission in the wavelength range of 430 nm to 500 nm.

[0030] A display according to the present invention is characterized by comprising any one of the color conversion sheets described above.

[0031] Furthermore, a lighting device according to the present invention is characterized by comprising any one of the color conversion sheets described above.

[0032] The present invention has the effect of realizing a polycyclic aromatic compound and a color-converting composition suitable as a color-converting material that can achieve both improved color reproducibility and high durability. The color-converting sheet of the present invention uses such a polycyclic aromatic compound or the like, thereby achieving the effect of achieving both improved color reproducibility and high durability. The light source unit, display, and lighting device of the present invention use such a color-converting sheet, thereby achieving the effect of achieving both improved color reproducibility and high durability.

[0033] Fig. 1 is a schematic cross-sectional view showing a first example of a color conversion sheet according to an embodiment of the present invention. Fig. 2 is a schematic cross-sectional view showing a second example of a color conversion sheet according to an embodiment of the present invention. Fig. 3 is a schematic cross-sectional view showing a third example of a color conversion sheet according to an embodiment of the present invention. Fig. 4 is a schematic cross-sectional view showing a fourth example of a color conversion sheet according to an embodiment of the present invention.

[0034] Preferred embodiments of the polycyclic aromatic compound, color-converting composition, color-converting sheet, light source unit, display, and lighting device according to the present invention will be specifically described below, but the present invention is not limited to the following embodiments and can be practiced with various modifications depending on the purpose and application.

[0035] <Polycyclic aromatic compound> The polycyclic aromatic compound according to an embodiment of the present invention is a color conversion material that constitutes a color conversion composition, a color conversion sheet, or the like. Specifically, this polycyclic aromatic compound is a compound that, when excited with excitation light, exhibits light emission with a peak wavelength observed in the region of 500 nm or more and 750 nm or less, has a HOMO level of −5.7 eV or less, and emits delayed fluorescence. Hereinafter, the polycyclic aromatic compound according to an embodiment of the present invention may be abbreviated as the “polycyclic aromatic compound of the present invention.”

[0036] (Emission Wavelength) The polycyclic aromatic compound of the present invention is a compound that exhibits emission observed in a peak wavelength range of 500 nm or more and 750 nm or less when using excitation light. For example, the polycyclic aromatic compound of the present invention preferably exhibits emission observed in a peak wavelength range of 500 nm or more and less than 580 nm when using excitation light. Hereinafter, emission observed in a peak wavelength range of 500 nm or more and less than 580 nm is referred to as "green emission."

[0037] The polycyclic aromatic compound of the present invention preferably emits green light by using excitation light having a wavelength in the range of 430 nm to 500 nm. Generally, the higher the energy of excitation light, the more likely it is that the light-emitting material will be decomposed. However, excitation light having a wavelength in the range of 430 nm to 500 nm has a relatively low excitation energy. Therefore, decomposition of the light-emitting material in the color-converting composition is suppressed, and green light with good color purity can be obtained.

[0038] Furthermore, the polycyclic aromatic compound of the present invention preferably exhibits, when excited with light, emission having a peak wavelength observed in the range of 580 nm to 750 nm. Hereinafter, emission having a peak wavelength observed in the range of 580 nm to 750 nm will be referred to as "red emission."

[0039] The polycyclic aromatic compound of the present invention preferably emits red light by using excitation light having a wavelength in the range of 430 nm to 500 nm. Generally, the higher the energy of excitation light, the more likely it is that the light-emitting material will be decomposed. However, excitation light having a wavelength in the range of 430 nm to 500 nm has a relatively low excitation energy. Therefore, decomposition of the light-emitting material in the color-converting composition is suppressed, and red light with good color purity can be obtained.

[0040] (Delayed Fluorescence) Compounds that emit delayed fluorescence have the characteristic of not easily generating singlet oxygen because their triplet excited state quickly converts to a singlet excited state. This characteristic has been found to prevent the degradation of luminescent materials, suppress changes in chromaticity over time, and improve durability. This mechanism will be explained in order.

[0041] First, we will explain the degradation mechanism of luminescent materials. The chromaticity change of a color-changing composition is caused by degradation of the luminescent material. This degradation of the luminescent material is caused by singlet oxygen. Singlet oxygen is an oxygen molecule in a singlet state in which the two electrons occupying the π* orbital (antibonding π orbital) of the oxygen molecule's molecular orbital have different spin directions, i.e., an excited state in which the total spin quantum number is zero. This excited state exists in two states: the Σ1 state, in which each of the two π* orbitals is occupied by an electron with a different spin direction, and the Δ1 state, in which only one of the π* orbitals is occupied by two electrons with a different spin direction. In the Δ1 state, the vacant electron orbital of singlet oxygen has strong electrophilicity and strong oxidizing power. Therefore, singlet oxygen is thought to cause oxidative degradation of the luminescent material.

[0042] Next, we will discuss the mechanism by which singlet oxygen is generated. It is thought that singlet oxygen is unlikely to be generated by direct photoexcitation of ground-state triplet oxygen. This is because the transition from ground-state triplet oxygen to excited-state singlet oxygen is a spin-forbidden transition, and therefore the transition probability is extremely low.

[0043] Therefore, it is believed that the generation of singlet oxygen in the color-changing composition is due to dye sensitization. In other words, it is believed that singlet oxygen is generated by the exchange of electrons and energy between the triplet excited state of the light-emitting material and triplet oxygen molecules in the ground state. The generation mechanism is believed to be as follows.

[0044] First, photoexcitation causes the light-emitting material to transition from the singlet ground state to the singlet excited state. Furthermore, a portion of the light-emitting material transitions from the singlet excited state to the triplet excited state through intersystem crossing. The transition from the triplet excited state to the singlet ground state of the generated light-emitting material is a spin-forbidden transition, so the transition probability is usually low and the triplet excited state has a long lifetime. However, when triplet oxygen in the ground state coexists, the spin forbidden state is lifted by the excitation from the ground state triplet oxygen to the excited state singlet oxygen, allowing the light-emitting material to quickly deactivate from the triplet excited state to the singlet ground state. This mechanism is called the Dexter mechanism (electron exchange mechanism).

[0045] The Dexter mechanism requires electron exchange via intermolecular wave function overlap, which is thought to require direct collision between an energy donor molecule (in this case, a light-emitting material in the triplet excited state) and an energy acceptor molecule (in this case, triplet oxygen in the ground state).

[0046] As mentioned above, compounds that emit delayed fluorescence have the property that the triplet excited state quickly converts to the singlet excited state, i.e., the lifetime of the triplet excited state is short. This reduces the probability of direct collision between the triplet excited state of the luminescent material and triplet oxygen in the ground state, making it difficult for singlet oxygen to be generated.

[0047] As described above, since the polycyclic aromatic compound of the present invention is a compound that emits delayed fluorescence, it is possible to suppress the generation of singlet oxygen and improve the durability of the color-changing composition.

[0048] (HOMO Level) The polycyclic aromatic compound of the present invention is a light-emitting material whose HOMO level is -5.7 eV or less. If the HOMO level of the light-emitting material is higher than -5.7 eV, repeated excitation-emission cycles will cause the light-emitting material to be oxidized and quenched due to interaction with oxygen contained in a composition containing the light-emitting material, resulting in a deterioration in durability. By ensuring that the HOMO level of the light-emitting material is -5.7 eV or less, the electron density of the light-emitting material is reduced. This improves the stability of the light-emitting material against oxygen, thereby improving durability.

[0049] As described above, by using a compound having a HOMO level of −5.7 eV or less and emitting delayed fluorescence as a light-emitting material (the polycyclic aromatic compound of the present invention), it is possible to suppress the generation of singlet oxygen and to suppress the reaction of a portion of the generated singlet oxygen with the light-emitting material, thereby improving the durability of the polycyclic aromatic compound of the present invention and, in turn, the durability of a color-converting composition containing the polycyclic aromatic compound.

[0050] The HOMO level of the polycyclic aromatic compound of the present invention is preferably -6.0 eV or less. When the HOMO level of the compound is -6.0 eV or less, the electron density of the compound can be further reduced. This improves the stability of the polycyclic aromatic compound of the present invention against oxygen, thereby improving the durability of the polycyclic aromatic compound. From the viewpoint of further enhancing this effect, the HOMO level of the polycyclic aromatic compound of the present invention is more preferably -6.2 eV or less, and even more preferably -6.5 eV or less.

[0051] The HOMO level of a compound can be calculated by calculation. In the present invention, the HOMO level is a value calculated by performing structural optimization in a 6-31G(d) basis set using the B3LYP density functional theory with the general-purpose quantum chemistry calculation program "Gaussian 16" program package (manufactured by Gaussian Corporation), and then performing calculations based on the optimized structure using the B3LYP density functional theory with a 6-311++G(d,p) basis set.

[0052] (Half Width) The half width of the emission spectrum at the emission peak wavelength of the polycyclic aromatic compound of the present invention is preferably 40 nm or less, more preferably 30 nm or less, and even more preferably 25 nm or less, from the viewpoints of obtaining light emission with high color purity and achieving a wide color gamut of the display when used in a liquid crystal display.

[0053] (Chemical Structure) The polycyclic aromatic compound of the present invention is not particularly limited, but is preferably a compound having a structure represented by the following general formula (1) or (2).

[0054]

[0055] In general formula (1) or general formula (2), ring Za, ring Zb, and ring Zc each independently represent a substituted or unsubstituted aryl ring having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroaryl ring having 6 to 30 ring carbon atoms.

[0056] In general formula (1), Z 1 and Z 2 are each independently an oxygen atom, NRa (a nitrogen atom having a substituent Ra), or a sulfur atom. 1 When R is NRa, the substituent R may be bonded to the ring Za or the ring Zb to form a ring. 2 When R is NRa, the substituent R may be bonded to the ring Z or the ring Zc to form a ring. E is a boron atom, a phosphorus atom, SiRa (a silicon atom having a substituent R), or P=O.

[0057] In the general formula (2), E 1 and E 2are each independently BRa (boron atom having a substituent Ra), PRa (phosphorus atom having a substituent Ra), SiRa2 (silicon atom having two substituents Ra), P(=O)Ra2 (phosphine oxide having two substituents Ra) or P(=S)Ra2 (phosphine sulfide having two substituents Ra), S(=O) or S(=O)2. E 1 When is BRa, PRa, SiRa2, P(=O)Ra2 or P(=S)Ra2, the substituent Ra may be bonded to ring Za or ring Zb to form a ring. 2 When is BRa, PRa, SiRa2, P(=O)Ra2 or P(=S)Ra2, the substituent Ra may be bonded to ring Za or ring Zc to form a ring.

[0058] The substituents Ra are each independently a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, or a substituted or unsubstituted alkyl group.

[0059] In all of the above groups, hydrogen may be deuterium. This also applies to the compounds or partial structures thereof described below. All of the above groups may be substituted or unsubstituted groups. Similarly, the compounds or partial structures thereof described below may be substituted or unsubstituted compounds or partial structures thereof. In the following description, for example, a substituted or unsubstituted aryl group having 6 to 40 carbon atoms refers to an aryl group in which the total number of carbon atoms, including the number of carbon atoms contained in substituents substituted on the aryl group, is 6 to 40. The same applies to other substituents that specify the number of carbon atoms.

[0060] In addition, in all of the above groups, the substituent when substituted is preferably an alkyl group, a cycloalkyl group, a heterocyclic group, an alkenyl group, a cycloalkenyl group, an alkynyl group, a hydroxyl group, a thiol group, an alkoxy group, an alkylthio group, an aryl ether group, an aryl thioether group, an aryl group, a heteroaryl group, a halogen, a cyano group, an aldehyde group, a carbonyl group, an acyl group, an ester group, an amide group, a carboxyl group, an oxycarbonyl group, a carbamoyl group, an amino group, a nitro group, a silyl group, a siloxanyl group, a boryl group, or a phosphine oxide group, and more preferably a specific substituent that is preferred in the description of each substituent.In addition, these substituents may be further substituted with the above-mentioned substituent.

[0061] The term "unsubstituted" in the context of "substituted or unsubstituted" means that a hydrogen atom or a deuterium atom has been substituted. The same applies to the term "substituted or unsubstituted" in the compounds or partial structures thereof described below.

[0062] Of all the groups mentioned above, the alkyl group refers to a saturated aliphatic hydrocarbon group such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, or a tert-butyl group, which may or may not have a substituent. When substituted, the additional substituent is not particularly limited, and examples thereof include an alkyl group, a halogen, an aryl group, and a heteroaryl group, and this point is also common to the following description. Furthermore, the number of carbon atoms in the alkyl group is not particularly limited, but is preferably in the range of 1 to 20, more preferably 1 to 8, from the viewpoints of ease of availability and cost.

[0063] The alkylene group refers to a divalent or higher group derived from a saturated aliphatic hydrocarbon group such as a methyl group or an ethyl group, which may or may not have a substituent. Preferred alkylene groups include a methylene group, an ethylene group, an n-propylene group, an isopropylene group, an n-butylene group, a pentylene group, and a hexylene group. The number of carbon atoms in the alkylene group portion is not particularly limited, but is preferably in the range of 1 to 20, more preferably 1 to 6.

[0064] The cycloalkyl group refers to a saturated alicyclic hydrocarbon group, such as a cyclopropyl group, a cyclohexyl group, a norbornyl group, an adamantyl group, or the like, which may or may not have a substituent. The number of carbon atoms in the alkyl group is not particularly limited, but is preferably in the range of 3 to 20.

[0065] The cycloalkylene group refers to a divalent or higher group derived from a saturated alicyclic hydrocarbon group such as a cyclopropyl group or a cyclohexyl group, which may or may not have a substituent. Preferred cycloalkylene groups include saturated alicyclic hydrocarbon groups such as a cyclopropylene group, a cyclohexylene group, a norbornylene group, and an adamantylene group. The number of carbon atoms in the cycloalkylene group portion is not particularly limited, but is preferably in the range of 3 to 20.

[0066] The heterocyclic group refers to an aliphatic ring having atoms other than carbon atoms in the ring, such as a pyran ring, a piperidine ring, or a cyclic amide, which may or may not have a substituent. The number of carbon atoms in the heterocyclic group is not particularly limited, but is preferably in the range of 2 to 20.

[0067] The alkenyl group refers to an unsaturated aliphatic hydrocarbon group containing a double bond, such as a vinyl group, an allyl group, or a butadienyl group, which may or may not have a substituent. The number of carbon atoms in the alkenyl group is not particularly limited, but is preferably in the range of 2 to 20.

[0068] The cycloalkenyl group refers to an unsaturated alicyclic hydrocarbon group containing a double bond, such as a cyclopentenyl group, a cyclopentadienyl group, or a cyclohexenyl group, which may or may not have a substituent. The number of carbon atoms in the cycloalkenyl group is not particularly limited, but is preferably in the range of 3 to 20.

[0069] The alkynyl group refers to an unsaturated aliphatic hydrocarbon group containing a triple bond, such as an ethynyl group, which may or may not have a substituent. The number of carbon atoms in the alkynyl group is not particularly limited, but is preferably in the range of 2 to 20.

[0070] The alkoxy group refers to a functional group in which an aliphatic hydrocarbon group is bonded via an ether bond, such as a methoxy group, an ethoxy group, or a propoxy group, and this aliphatic hydrocarbon group may or may not have a substituent. The number of carbon atoms in the alkoxy group is not particularly limited, but is preferably in the range of 1 to 20.

[0071] An alkylthio group is an alkoxy group in which the oxygen atom of the ether bond is replaced with a sulfur atom. The hydrocarbon group of the alkylthio group may or may not have a substituent. The number of carbon atoms in the alkylthio group is not particularly limited, but is preferably in the range of 1 to 20.

[0072] The aryl ether group refers to a functional group to which an aromatic hydrocarbon group, such as a phenoxy group, is bonded via an ether bond, and the aromatic hydrocarbon group may or may not have a substituent. The number of carbon atoms in the aryl ether group is not particularly limited, but is preferably in the range of 6 to 40.

[0073] An aryl thioether group is an aryl ether group in which the oxygen atom of the ether bond is substituted with a sulfur atom. The aromatic hydrocarbon group in the aryl thioether group may or may not have a substituent. The number of carbon atoms in the aryl thioether group is not particularly limited, but is preferably in the range of 6 to 40.

[0074] The aryl group refers to an aromatic hydrocarbon group such as a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthryl group, an anthracenyl group, a benzophenanthryl group, a benzanthracenyl group, a chrysenyl group, a pyrenyl group, a fluoranthenyl group, a triphenylenyl group, a benzofluoranthenyl group, a dibenzoanthracenyl group, a perylenyl group, or a helicenyl group. Among these, a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a phenanthryl group, an anthracenyl group, a pyrenyl group, a fluoranthenyl group, or a triphenylenyl group is preferred. The aryl group may or may not have a substituent. When the aryl group has a substituent, the substituents may form a cyclic structure. An example of an aryl group in which the substituents form a cyclic structure is a spirofluorenyl group. The number of carbon atoms in the aryl group is not particularly limited, but is preferably in the range of 6 or more and 100 or less, more preferably 6 or more and 50 or less, and even more preferably 6 or more and 30 or less.

[0075] When each of the substituents is further substituted with an aryl group, the aryl group is preferably a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a phenanthryl group, or an anthracenyl group, more preferably a phenyl group, a biphenyl group, a terphenyl group, or a naphthyl group, and particularly preferably a phenyl group.

[0076] Examples of heteroaryl groups include pyridyl, furanyl, thienyl, quinolinyl, isoquinolinyl, pyrazinyl, pyrimidyl, pyridazinyl, triazinyl, naphthyridinyl, cinnolinyl, phthalazinyl, quinoxalinyl, quinazolinyl, benzofuranyl, benzothienyl, indolyl, dibenzofuranyl, dibenzothienyl, carbazolyl, and benzocarbazolyl. It refers to a cyclic aromatic group having one or more atoms other than carbon in the ring, such as a benzoyl group, a carbolinyl group, an indolocarbazolyl group, a benzofurocarbazolyl group, a benzothienocarbazolyl group, a dihydroindenocarbazolyl group, a benzoquinolinyl group, an acridinyl group, a dibenzoacridinyl group, a benzimidazolyl group, an imidazopyridyl group, a benzoxazolyl group, a benzothiazolyl group, or a phenanthrolinyl group. However, a naphthyridinyl group refers to a 1,5-naphthyridinyl group, a 1,6-naphthyridinyl group, a 1,7-naphthyridinyl group, a 1,8-naphthyridinyl group, a 2,6-naphthyridinyl group, or a 2,7-naphthyridinyl group. The heteroaryl group may or may not have a substituent. The number of carbon atoms in the heteroaryl group is not particularly limited, but is preferably in the range of 2 or more and 40 or less, and more preferably 2 or more and 30 or less.

[0077] When each substituent is further substituted with a heteroaryl group, the heteroaryl group is preferably a pyridyl group, a furanyl group, a thienyl group, a quinolinyl group, a pyrimidyl group, a triazinyl group, a benzofuranyl group, a benzothienyl group, an indolyl group, a dibenzofuranyl group, a dibenzothienyl group, a carbazolyl group, a benzimidazolyl group, an imidazopyridyl group, a benzoxazolyl group, a benzothiazolyl group, or a phenanthrolinyl group, more preferably a pyridyl group, a furanyl group, a thienyl group, or a quinolinyl group, and particularly preferably a pyridyl group.

[0078] The term "halogen" refers to an atom selected from fluorine, chlorine, bromine, and iodine. The carbonyl group, carboxyl group, oxycarbonyl group, and carbamoyl group may or may not have a substituent. Examples of the substituent include an alkyl group, a cycloalkyl group, an aryl group, and a heteroaryl group, and these substituents may be further substituted. The number of carbon atoms in the carbonyl group is not particularly limited, but is preferably in the range of 6 to 40.

[0079] The ester group refers to a functional group in which, for example, an alkyl group, a cycloalkyl group, an aryl group, a heteroaryl group, or the like is bonded via an ester bond, and this substituent may be further substituted. The number of carbon atoms in the ester group is not particularly limited, but is preferably in the range of 1 to 200, more preferably in the range of 1 to 100. More specifically, examples of the ester group include methyl ester groups such as a methoxycarbonyl group, ethyl ester groups such as an ethoxycarbonyl group, propyl ester groups such as a propoxycarbonyl group, butyl ester groups such as a butoxycarbonyl group, isopropyl ester groups such as an isopropoxymethoxycarbonyl group, hexyl ester groups such as a hexyloxycarbonyl group, and phenyl ester groups such as a phenoxycarbonyl group.

[0080] The amide group refers to a functional group in which a substituent such as an alkyl group, a cycloalkyl group, an aryl group, or a heteroaryl group is bonded via an amide bond, and this substituent may be further substituted. The number of carbon atoms in the amide group is not particularly limited, but is preferably in the range of 1 to 20. More specific examples of the amide group include a methylamide group, an ethylamide group, a propylamide group, a butylamide group, an isopropylamide group, a hexylamide group, and a phenylamide group.

[0081] The amino group is a substituted or unsubstituted amino group. The amino group may or may not have a substituent, and in the case of a substitution, examples of the substituent include an aryl group, a heteroaryl group, a linear alkyl group, and a branched alkyl group. Preferred aryl groups and heteroaryl groups are a phenyl group, a naphthyl group, a pyridyl group, and a quinolinyl group. These substituents may be further substituted. The number of carbon atoms is not particularly limited, but is preferably in the range of 2 to 50, more preferably 6 to 40, and particularly preferably 6 to 30.

[0082] The silyl group refers to, for example, alkylsilyl groups such as trimethylsilyl group, triethylsilyl group, tert-butyldimethylsilyl group, propyldimethylsilyl group, and vinyldimethylsilyl group, and arylsilyl groups such as phenyldimethylsilyl group, tert-butyldiphenylsilyl group, triphenylsilyl group, and trinaphthylsilyl group. The substituent on silicon may be further substituted. The number of carbon atoms in the silyl group is not particularly limited, but is preferably in the range of 1 to 30.

[0083] The siloxanyl group refers to a silicon compound group connected via an ether bond, such as a trimethylsiloxanyl group. The substituent on the silicon may be further substituted. The number of carbon atoms in the siloxanyl group is not particularly limited, but is preferably in the range of 1 to 30. The boryl group is a substituted or unsubstituted boryl group. The boryl group may or may not have a substituent, and in the case of substitution, examples of the substituent include an aryl group, a heteroaryl group, a linear alkyl group, a branched alkyl group, an aryl ether group, an alkoxy group, and a hydroxyl group. Among these, an aryl group and an aryl ether group are preferred. The number of carbon atoms in the boryl group is not particularly limited, but is preferably in the range of 1 to 30.

[0084] The acyl group refers to a functional group in which a substituent such as an alkyl group, a cycloalkyl group, an aryl group, or a heteroaryl group is bonded via a carbonyl bond, and this substituent may be further substituted. The number of carbon atoms in the acyl group is not particularly limited, but is preferably in the range of 1 to 20. More specifically, examples of the acyl group include an acetyl group, a propionyl group, a benzoyl group, and an acrylyl group.

[0085] The sulfonyl group is a functional group in which a substituent such as an alkyl group, a cycloalkyl group, an aryl group, or a heteroaryl group is bonded via an -S(=O)2- bond, and this substituent may be further substituted. The number of carbon atoms in the sulfonyl group is not particularly limited, but is preferably in the range of 1 to 30.

[0086] The sulfoxide group refers to a functional group in which a substituent such as an alkyl group, a cycloalkyl group, an aryl group, or a heteroaryl group is bonded via an —S(═O)— bond, and this substituent may be further substituted. The number of carbon atoms in the sulfoxide group is not particularly limited, but is preferably in the range of 1 to 30.

[0087] The phosphine oxide group is a group represented by the formula -P(=O)R 10 R 11 The R of the phosphine oxide group is a group represented by the formula: 10 and R 11 is selected in the same manner as the above-described substituent Ra. The number of carbon atoms in the phosphine oxide group is not particularly limited, but is preferably in the range of 1 to 30.

[0088] Examples of the aryl ring having 6 to 30 ring carbon atoms include a benzene ring, a naphthalene ring, a fluorene ring, a benzofluorene ring, a dibenzofluorene ring, a phenanthrene ring, an anthracene ring, a benzophenanthrene ring, a benzanthracene ring, a chrysene ring, a pyrene ring, a fluoranthene ring, a triphenylene ring, a benzofluoranthene ring, a dibenzanthracene ring, a perylene ring, and a helicene ring.

[0089] Examples of heteroaryl rings having 6 to 30 ring carbon atoms include a pyridine ring, a furan group, a thiophene ring, a quinoline ring, an isoquinoline ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring, a naphthyridine ring, a cinnoline ring, a phthalazine ring, a quinoxaline ring, a quinazoline ring, a benzofuran ring, a benzothiophene ring, an indole ring, a dibenzofuran ring, a dibenzothiophene ring, a carbazole ring, a benzocarbazole ring, a carboline ring, an indolocarbazole ring, a benzofurocarbazole ring, a benzothienocarbazole ring, a dihydroindenocarbazole ring, a benzoquinoline ring, an acridine ring, a dibenzoacridine ring, an imidazole ring, an oxazole ring, a thiazole ring, a benzimidazole ring, an imidazopyridine ring, a benzoxazole ring, a benzothiazole ring, and a phenanthroline ring.

[0090] The compounds represented by general formula (1) or (2) have a strong and highly planar skeleton. Therefore, the compounds represented by general formula (1) or (2) exhibit high luminescence quantum yields, and the peak half-width of the emission spectrum of the compounds represented by general formula (1) or (2) is small. Therefore, the compounds represented by general formula (1) or (2) can achieve highly efficient color conversion and high color purity.

[0091] In addition, the compound represented by general formula (1) or (2) uses an electron-donating substituent and an electron-accepting substituent to localize the HOMO and LUMO within the molecule, thereby efficiently causing reverse intersystem crossing from a triplet excited state to a singlet excited state, resulting in a compound that emits delayed fluorescence. Therefore, the durability of the compound represented by general formula (1) or (2) can be improved.

[0092] Furthermore, when the compound represented by general formula (1) or general formula (2) has at least one electron-withdrawing group, the electron density of the compound represented by general formula (1) or general formula (2) is lower than when the compound does not have an electron-withdrawing group. This improves the stability of the compound represented by general formula (1) or general formula (2) against singlet oxygen, and as a result, the durability of the compound is further improved. For this reason, it is preferable that the compound represented by general formula (1) or general formula (2) has at least one electron-withdrawing group.

[0093] The compound represented by general formula (1) or (2) preferably has at least one electron-withdrawing group as a substituent on ring Za, ring Zb, or ring Zc, or as a substituent on the ring when these rings form a ring with an adjacent group. 1 is NRa, and when the substituent Ra is bonded to the ring Zb to form a ring, the ring may have an electron-withdrawing group as a substituent.

[0094] The compound represented by general formula (1) or (2) preferably has two or more electron-withdrawing groups, which further improves the stability of the compound represented by general formula (1) or (2) against singlet oxygen, thereby further improving the durability of the compound.

[0095] Electron-withdrawing groups, also called electron-accepting groups, are atomic groups that attract electrons from substituted atomic groups due to inductive effects or resonance effects in organic electronics theory. Examples of electron-withdrawing groups include those whose Hammett's rule substituent constant (σp(para)) takes a positive value. The Hammett's rule substituent constant (σp(para)) can be cited from the revised 5th edition of the Basic Chemistry Handbook (page II-380). Note that although there are examples where phenyl groups also take a positive value, phenyl groups are not included in the electron-withdrawing groups of the present invention.

[0096] Preferred examples of electron-withdrawing groups include a cyano group, an acyl group, an ester group, an amide group, a sulfonyl group, a sulfonate ester group, or a sulfonamide group. These groups can efficiently reduce the electron density of the basic skeleton. Furthermore, these groups are preferred because they have moderate polarity, which improves the solubility of the compound represented by general formula (1) or general formula (2) in solvents, resins, etc. when producing a color-changing composition. This further improves the stability of the compound represented by general formula (1) or general formula (2) against singlet oxygen, thereby further improving the durability of the compound.

[0097] A particularly preferred example of the electron-withdrawing group is an ester group. When the electron-withdrawing group is an ester group, the electron density of the basic skeleton can be appropriately reduced without widening the conjugation of the basic skeleton. Therefore, the durability of the compound represented by general formula (1) or general formula (2) can be further improved without impairing the luminous efficiency and color purity.

[0098] Among ester groups, fluorine-containing ester groups (ester groups containing a fluorine atom) are particularly preferred. For example, it is preferred that the above-mentioned alkyl ester groups such as methyl ester groups or aryl ester groups such as phenyl ester groups are substituted with a fluorine atom or a group containing a fluorine atom. Examples of methyl ester groups substituted with a fluorine atom include trifluoromethyl ester groups. Examples of phenyl ester groups substituted with a group containing a fluorine atom include trifluoromethylphenyl groups and (3,5-bistrifluoromethylphenyl)phenyl ester groups.

[0099] Furthermore, it is preferable that the electron-withdrawing group be sterically bulky. If the electron-withdrawing group is bulky, the degree of freedom of molecular movement of the compound represented by general formula (1) or general formula (2) is reduced due to its structure, and molecular movement within the resin is suppressed. Furthermore, since the electron-withdrawing group acts as a steric hindrance group, the compounds represented by general formula (1) or general formula (2) do not interact with each other, and stability is further improved. Thus, the sterically bulky electron-withdrawing group can suppress aggregation between molecules, and the durability of the compound represented by general formula (1) or general formula (2) is improved.

[0100] The number of carbon atoms constituting the electron-withdrawing group is not particularly limited, but is preferably in the range of 2 or more and 200 or less, more preferably 6 or more and 200 or less, and particularly preferably 20 or more and 200 or less.

[0101] In general formula (1), Z 1 and Z 2 is preferably an oxygen atom or NRa, because the π-conjugated system of the compound represented by general formula (1) is efficiently expanded, and reverse intersystem crossing from the triplet excited state to the singlet excited state occurs more efficiently, thereby further improving the durability of the compound.

[0102] In the general formula (1) or (2), E is preferably a boron atom, and E 1 and E 2 is preferably BRa, because the π-conjugated system of the compound represented by general formula (1) or general formula (2) is efficiently expanded, and reverse intersystem crossing from the triplet excited state to the singlet excited state occurs more efficiently, thereby further improving the durability of the compound.

[0103] In general formula (1) or general formula (2), ring Za, ring Zb, and ring Zc are preferably benzene rings, because the π-conjugated system of the compound represented by general formula (1) or general formula (2) is efficiently expanded and reverse intersystem crossing from the triplet excited state to the singlet excited state occurs more efficiently, thereby further improving the durability of the compound.

[0104] Examples of the polycyclic aromatic compound of the present invention are shown below, but the polycyclic aromatic compound of the present invention is not limited to these.

[0105]

[0106]

[0107] The polycyclic aromatic compound of the present invention can be produced by referring to the methods described in, for example, JP 2020-097561 A, WO 2015 / 102118 A, and WO 2019 / 164340 A. That is, the desired polycyclic aromatic compound can be obtained by reacting a halogen compound with a boron raw material in the presence of butyllithium. However, the present invention is not limited thereto.

[0108] Furthermore, when introducing an aryl group or a heteroaryl group, a method of generating a carbon-carbon bond using a coupling reaction between a halogenated derivative and a boronic acid or a boronate ester derivative can be used, but the present invention is not limited to this. Similarly, when introducing an electron-withdrawing group, for example, a halogenated derivative previously substituted with an electron-withdrawing group can be used as a starting material, or the skeleton can be formed and then the group can be introduced using various reactions, but the present invention is not limited to this.

[0109] (Polycyclic aromatic compound according to another aspect of the present invention) A polycyclic aromatic compound according to another aspect of the present invention is a compound represented by general formula (11) or general formula (12), and has at least one electron-withdrawing group.

[0110]

[0111] In general formula (11) or general formula (12), ring Za, ring Zb, and ring Zc each independently represent a substituted or unsubstituted aryl ring having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroaryl ring having 6 to 30 ring carbon atoms.

[0112] In the general formula (11), Z 1 and Z 2 are each independently an oxygen atom, NRa (a nitrogen atom having a substituent Ra), or a sulfur atom.1 When R is NRa, the substituent R may be bonded to the ring Za or the ring Zb to form a ring. 2 When R is NRa, the substituent R may be bonded to the ring Z or the ring Zc to form a ring. E is a boron atom, a phosphorus atom, SiRa (a silicon atom having a substituent R), or P=O.

[0113] In the general formula (12), E 1 and E 2 are each independently BRa (boron atom having a substituent Ra), PRa (phosphorus atom having a substituent Ra), SiRa2 (silicon atom having two substituents Ra), P(=O)Ra2 (phosphine oxide having two substituents Ra) or P(=S)Ra2 (phosphine sulfide having two substituents Ra), S(=O) or S(=O)2. E 1 When is BRa, PRa, SiRa2, P(=O)Ra2 or P(=S)Ra2, the substituent Ra may be bonded to ring Za or ring Zb to form a ring. 2 When is BRa, PRa, SiRa2, P(=O)Ra2 or P(=S)Ra2, the substituent Ra may be bonded to ring Za or ring Zc to form a ring.

[0114] The substituents Ra are each independently a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, or a substituted or unsubstituted alkyl group. The compound represented by general formula (11) or general formula (12) has at least one electron-withdrawing group.

[0115] The compound represented by general formula (11) is a compound represented by the above general formula (1) having at least one electron-withdrawing group. The compound represented by general formula (12) is a compound represented by the above general formula (2) having at least one electron-withdrawing group. The explanation of each group in the compound represented by general formula (11) or general formula (12) is the same as that in the compound represented by general formula (1) or general formula (2).

[0116] Because the compound represented by general formula (11) or general formula (12) has at least one electron-withdrawing group, the electron density of the compound represented by general formula (11) or general formula (12) is lower than that of a compound not having an electron-withdrawing group. This improves the stability of the compound represented by general formula (11) or general formula (12) against singlet oxygen, resulting in particularly improved durability of the compound. Therefore, in the case of the compound represented by general formula (11) or general formula (12), regardless of whether the HOMO level is −5.7 eV or lower, it is possible to achieve the effect of realizing a polycyclic aromatic compound and a color-changing composition suitable as a color-changing material that can achieve both improved color reproducibility and high durability.

[0117] <Color-Converting Composition> The color-converting composition according to an embodiment of the present invention converts incident light from a light-emitting body such as a light source into light with a wavelength different from that of the incident light, and preferably contains the polycyclic aromatic compound of the present invention and a binder resin described above. Here, "converting into light with a wavelength different from that of the incident light" preferably converts into light with a wavelength longer than that of the incident light.

[0118] The color-converting composition according to the embodiment of the present invention may contain other compounds as needed in addition to the polycyclic aromatic compound of the present invention. For example, an assist dopant such as rubrene may be contained to further increase the efficiency of energy transfer from excitation light to the polycyclic aromatic compound of the present invention. Furthermore, if an emission color other than the emission color of the polycyclic aromatic compound of the present invention is desired, a desired organic light-emitting material, such as a coumarin derivative or a rhodamine derivative, can be added. In addition to organic light-emitting materials, known light-emitting materials such as inorganic phosphors, fluorescent pigments, fluorescent dyes, and quantum dots can also be added in combination.

[0119] Examples of organic light-emitting materials other than the polycyclic aromatic compound of the present invention are shown below, but the present invention is not particularly limited to these.

[0120]

[0121] In the present invention, the color-changing composition preferably emits green light when irradiated with excitation light, and more preferably emits red light when irradiated with excitation light.

[0122] (Binder Resin) The binder resin forms a continuous phase and may be any material that is excellent in moldability, transparency, heat resistance, etc. Examples of binder resins include known materials such as photocurable resist materials having reactive vinyl groups, such as acrylic acid-based, methacrylic acid-based, polyvinyl cinnamate-based, and cyclic rubber-based materials, epoxy resins, silicone resins (including organopolysiloxane cured products (crosslinked products) such as silicone rubber and silicone gel), urea resins, fluororesins, polycarbonate resins, acrylic resins, urethane resins, melamine resins, polyvinyl resins, polyamide resins, phenolic resins, polyvinyl alcohol resins, cellulose resins, aliphatic ester resins, aromatic ester resins, aliphatic polyolefin resins, and aromatic polyolefin resins. Furthermore, copolymer resins of these may also be used as the binder resin. By appropriately designing these resins, binder resins useful for the color conversion composition and color conversion sheet according to the present invention can be obtained. Among these resins, thermoplastic resins are more preferred because of the ease of the sheet formation process. Among thermoplastic resins, epoxy resins, silicone resins, acrylic resins, ester resins, olefin resins, or mixtures thereof can be preferably used from the viewpoints of transparency, heat resistance, etc. Furthermore, from the viewpoint of durability, particularly preferred thermoplastic resins are acrylic resins, ester resins, and cycloolefin resins.

[0123] Suitable specific examples of binder resins include those described in WO 2016 / 190283, WO 2017 / 61337, WO 2018 / 43237, WO 2019 / 21813, and WO 2019 / 188019.

[0124] The binder resin may contain additives such as dispersants and leveling agents for stabilizing the coating film, or may contain adhesion promoters such as silane coupling agents as sheet surface modifiers. The binder resin may also contain inorganic particles such as silica particles and silicone microparticles as agents for inhibiting the precipitation of color conversion materials.

[0125] In the color-converting composition for producing a color-converting sheet according to an embodiment of the present invention, the binder resin preferably contains, as an additional component, a hydrosilylation reaction retarder such as acetylene alcohol to inhibit curing at room temperature and thereby extend the pot life. Furthermore, the binder resin may contain, as necessary, fine particles such as fumed silica, glass powder, and quartz powder, inorganic fillers and pigments such as titanium oxide, zirconia oxide, barium titanate, and zinc oxide, flame retardants, heat-resistant agents, antioxidants, dispersants, solvents, and adhesion promoters such as silane coupling agents and titanium coupling agents, within the scope of the present invention.

[0126] (Solvent) The color-changing composition according to the embodiment of the present invention may contain a solvent. The solvent is not particularly limited as long as it can adjust the viscosity of the resin in a fluid state and does not excessively affect the luminescence and durability of the luminescent material. Examples of such solvents include toluene, methyl ethyl ketone, methyl isobutyl ketone, hexane, acetone, terpineol, Texanol, methyl cellosolve, butyl carbitol, butyl carbitol acetate, and propylene glycol monomethyl ether acetate. Two or more of these solvents may also be mixed and used. Among these solvents, toluene is particularly preferred because it does not affect the degradation of the polycyclic aromatic compound of the present invention and leaves little residual solvent after drying.

[0127] (Other Components) In addition to the polycyclic aromatic compound and binder resin of the present invention described above, the color-converting composition according to the embodiment of the present invention may contain other components (additives), such as a light stabilizer, an antioxidant, a processing and heat stabilizer, a light resistance stabilizer such as an ultraviolet absorber, scattering particles, silicone microparticles, and a silane coupling agent.

[0128] Examples of light stabilizers include, but are not limited to, tertiary amines, catechol derivatives, nickel compounds, and complexes or salts with organic acids containing at least one transition metal selected from the group consisting of Sc, V, Mn, Fe, Co, Cu, Y, Zr, Mo, Ag, and lanthanoids. These light stabilizers may be used alone or in combination.

[0129] Examples of the antioxidant include, but are not limited to, phenolic antioxidants such as 2,6-di-tert-butyl-p-cresol and 2,6-di-tert-butyl-4-ethylphenol. These antioxidants may be used alone or in combination.

[0130] Examples of processing and heat stabilizers include, but are not limited to, phosphorus-based stabilizers such as tributyl phosphite, tricyclohexyl phosphite, triethyl phosphine, and diphenylbutyl phosphine. These stabilizers may be used alone or in combination.

[0131] Examples of the light resistance stabilizer include, but are not limited to, benzotriazoles such as 2-(5-methyl-2-hydroxyphenyl)benzotriazole and 2-[2-hydroxy-3,5-bis(α,α-dimethylbenzyl)phenyl]-2H-benzotriazole. These light resistance stabilizers may be used alone or in combination.

[0132] The scattering particles are preferably inorganic particles having a refractive index of 1.7 to 2.8, such as titania, zirconia, alumina, ceria, tin oxide, indium oxide, iron oxide, zinc oxide, aluminum nitride, aluminum, tin, titanium or zirconium sulfide, and titanium or zirconium hydroxide.

[0133] In the color-converting composition according to the embodiment of the present invention, the content of these additives varies depending on the molar absorption coefficient, luminescence quantum yield, and absorption intensity at the excitation wavelength of the compound, as well as the thickness and transmittance of the color-converting sheet to be produced, but is usually 1.0 × 10 -3 The content of these additives is preferably 1.0×10 to 30 parts by weight based on 100 parts by weight of the binder resin. -2 It is more preferable that the amount is 1.0×10 parts by weight or more and 15 parts by weight or less. -1 It is particularly preferable that the amount is from 1 part by weight to 10 parts by weight.

[0134] <Method of Manufacturing Color-Converting Composition> An example of a method of manufacturing a color-converting composition according to an embodiment of the present invention is described below. In this method of manufacturing, predetermined amounts of the polycyclic aromatic compound of the present invention, binder resin, solvent, etc. are mixed. After mixing the above components to a predetermined composition, the color-converting composition is obtained by homogenizing and dispersing the components using a stirrer / kneader such as a homogenizer, a planetary mixer, a three-roller mixer, a ball mill, a planetary ball mill, or a bead mill. After mixing and dispersing, or during the mixing and dispersing process, degassing is preferably performed under vacuum or reduced pressure conditions. It is also possible to mix certain components in advance, or to perform treatments such as aging. It is also possible to remove the solvent using an evaporator to achieve a desired solids concentration.

[0135] <Color Conversion Sheet> The color conversion sheet according to an embodiment of the present invention converts incident light from a light emitter such as a light source into light with a wavelength different from that of the incident light, and preferably contains the polycyclic aromatic compound of the present invention and a binder resin described above. Here, "converting into light with a wavelength different from that of the incident light" preferably converts into light with a wavelength longer than that of the incident light.

[0136] In the present invention, the color conversion sheet preferably includes a color conversion layer that is a layer made of the above-mentioned color conversion composition or a cured product thereof. The cured product of the color conversion composition is preferably included in the color conversion sheet as a layer obtained by curing the color conversion composition (a layer made of the cured product of the color conversion composition). Typical structural examples of color conversion sheets include the following four, for example.

[0137] Fig. 1 is a schematic cross-sectional view showing a first example of a color conversion sheet according to an embodiment of the present invention. As shown in Fig. 1, this first example color conversion sheet 1A is a single-layer film composed of a color conversion layer 11. The color conversion layer 11 is a layer made of a cured product of the color conversion composition described above.

[0138] 2 is a schematic cross-sectional view showing a second example of a color conversion sheet according to an embodiment of the present invention. As shown in FIG. 2, this second example of a color conversion sheet 1B is a laminate of a base layer 10 and a color conversion layer 11. In this structural example of color conversion sheet 1B, the color conversion layer 11 is laminated on the base layer 10.

[0139] 3 is a schematic cross-sectional view showing a third example of a color conversion sheet according to an embodiment of the present invention. As shown in FIG. 3, this third example of a color conversion sheet 1C is a laminate of multiple base material layers 10 and a color conversion layer 11. In this structural example of color conversion sheet 1C, the color conversion layer 11 is sandwiched between multiple base material layers 10.

[0140] 4 is a schematic cross-sectional view showing a fourth example of a color conversion sheet according to an embodiment of the present invention. As shown in FIG. 4, this fourth example color conversion sheet 1D is a laminate of multiple base layers 10, a color conversion layer 11, and multiple barrier films 12. In this structural example of color conversion sheet 1D, the color conversion layer 11 is sandwiched between multiple barrier films 12, and this laminate of the color conversion layer 11 and the multiple barrier films 12 is further sandwiched between multiple base layers 10. That is, color conversion sheet 1D may have a barrier film 12 as shown in FIG. 4 to prevent deterioration of the color conversion layer 11 due to oxygen, moisture, or heat.

[0141] (Substrate Layer) The substrate layer (e.g., substrate layer 10 shown in Figures 2 to 4) can be made of any known metal, film, glass, ceramic, paper, or the like, without any particular limitations. Among these, glass and resin films are preferred due to the ease of producing and molding the color conversion sheet. Furthermore, high-strength films are preferred so that the film-like substrate layer does not break when handled. Resin films are preferred in terms of the required properties and economic efficiency, and plastic films selected from the group consisting of polyethylene terephthalate (PET), polyphenylene sulfide, polycarbonate, and polypropylene are particularly preferred in terms of economic efficiency and ease of handling. Furthermore, when drying the color conversion sheet or when compressing and molding the color conversion sheet at high temperatures of 200°C or higher using an extruder, polyimide films are preferred in terms of heat resistance. To facilitate film peeling, the surface of the substrate layer may be pre-treated with a release agent.

[0142] The thickness of the substrate layer is not particularly limited, but the lower limit is preferably 25 μm or more, more preferably 38 μm or more, and the upper limit is preferably 5000 μm or less, more preferably 3000 μm or less.

[0143] (Color conversion layer) The color conversion layer (for example, color conversion layer 11 shown in Figures 1 to 4) can be formed by applying the color conversion composition prepared by the method described above to an underlayer such as a base layer or a barrier film, and drying it.

[0144] The thickness of the color conversion layer is not particularly limited, but is preferably 10 μm to 1000 μm. The lower limit of the thickness of the color conversion layer is more preferably 30 μm or more. The upper limit of the thickness of the color conversion layer is more preferably 200 μm or less, even more preferably 100 μm or less, and particularly preferably 50 μm or less. The film thickness of the color conversion sheet in the present invention refers to the film thickness (average film thickness) measured in accordance with Method A, a thickness measurement method by mechanical scanning, in JIS K7130 (1999) Plastics - Films and Sheets - Thickness Measurement Methods.

[0145] In the color conversion sheet of the present invention, the color conversion layer may be one layer or two or more layers. When the color conversion layer is two or more layers, it is preferable that at least one layer contains the polycyclic aromatic compound of the present invention.

[0146] In addition to the polycyclic aromatic compound and binder resin of the present invention described above, the color conversion layer may contain other components (additives), such as a light stabilizer, an antioxidant, a processing and heat stabilizer, a light resistance stabilizer such as an ultraviolet absorber, scattering particles, silicone microparticles, and a silane coupling agent.

[0147] (Barrier Film) A barrier film (e.g., barrier film 12 shown in FIG. 4 ) is appropriately used when, for example, improving the gas barrier properties of the color conversion layer. Examples of this barrier film include inorganic oxides such as silicon oxide, aluminum oxide, titanium oxide, tantalum oxide, zinc oxide, tin oxide, indium oxide, yttrium oxide, and magnesium oxide; inorganic nitrides such as silicon nitride, aluminum nitride, titanium nitride, and silicon carbonitride; mixtures thereof; metal oxide thin films or metal nitride thin films containing these with added elements; and films made of various resins such as polyvinylidene chloride, acrylic resins, silicone resins, melamine resins, urethane resins, fluorine-containing resins, and polyvinyl alcohol-based resins such as saponified vinyl acetate. Examples of barrier films having a moisture barrier function include films made of various resins such as polyethylene, polypropylene, nylon, polyvinylidene chloride, copolymers of vinylidene chloride and vinyl chloride, copolymers of vinylidene chloride and acrylonitrile, fluorine-containing resins, and polyvinyl alcohol-based resins such as saponified vinyl acetate.

[0148] The barrier film may be provided on both sides of the color conversion layer 11, as in the barrier film 12 exemplified in Fig. 4, or on only one side of the color conversion layer 11. Furthermore, depending on the functions required of the color conversion sheet, an auxiliary layer having an anti-reflection function, an anti-glare function, an anti-reflection and anti-glare function, a hard coat function (abrasion resistance function), an anti-static function, an anti-fouling function, an electromagnetic wave shielding function, an infrared ray blocking function, an ultraviolet ray blocking function, a polarizing function, or a color-tuning function may be further provided.

[0149] (Other Films) The color conversion sheet according to the embodiment of the present invention may further include a dual brightness enhancement film (DBEF), a diffusion sheet, a prism sheet, a wavelength-selective reflective film, etc. Suitable specific examples of the wavelength-selective reflective film include those described in WO 2017 / 164155 and JP 2018-81250 A.

[0150] <Light Source Unit> The light source unit according to the embodiment of the present invention is configured to include at least a light source and the above-described color conversion sheet. The light source included in the light source unit according to the embodiment of the present invention is a source of the above-described excitation light. The arrangement of the light source and the color conversion sheet is not particularly limited, and the light source and the color conversion sheet may be closely attached to each other, or a remote phosphor type in which the light source and the color conversion sheet are separated from each other may be used. Furthermore, the light source unit may be further configured to include a color filter in order to enhance color purity.

[0151] (Light Source) Any type of excitation light from a light source can be used as long as it emits light in a wavelength range that can be absorbed by the luminescent substance to be mixed, such as the polycyclic aromatic compound of the present invention. For example, any excitation light can in principle be used, such as a hot cathode tube, a cold cathode tube, a fluorescent light source such as inorganic electroluminescence (EL), an organic EL element light source, an LED light source, an incandescent light source, or sunlight. In particular, light from an LED light source is preferred as excitation light.

[0152] The excitation light may have one emission peak or two or more emission peaks, but in order to improve color purity, it is preferable to use one emission peak. It is also possible to use any combination of multiple excitation light sources with different emission peaks.

[0153] In display and lighting applications, the light source of the excitation light is preferably a light-emitting diode having a maximum emission wavelength in the range of 430 nm to 500 nm, in order to enhance the color purity of blue light. Furthermore, this light source preferably has a maximum emission wavelength in the range of 440 nm to 470 nm. Excitation light in the wavelength range of 430 nm to 500 nm has relatively low excitation energy, and can prevent decomposition of light-emitting substances such as the polycyclic aromatic compound of the present invention.

[0154] The light source unit of the present invention can be used for applications such as displays, lighting, interiors, signs, and billboards, and is particularly suitable for use in displays and lighting.

[0155] <Display, Lighting Device> A display according to an embodiment of the present invention includes at least the color conversion sheet described above. For example, a display such as a liquid crystal display uses a light source unit having the above-described light source and color conversion sheet as a backlight unit. Furthermore, a lighting device according to an embodiment of the present invention includes at least the above-described color conversion sheet. For example, this lighting device is configured to emit white light by combining a blue LED light source as a light source unit with a color conversion sheet that converts blue light from the blue LED light source into light with a longer wavelength.

[0156] <Light-emitting device> In an embodiment of the present invention, the light-emitting device comprises an anode, a cathode, and an organic layer interposed between the anode and the cathode. The organic layer of this light-emitting device emits light in response to electrical energy. The polycyclic aromatic compound of the present invention may be used in any layer of this light-emitting device, but is preferably used in the light-emitting layer of this light-emitting device because it has a high fluorescence quantum yield. In particular, the polycyclic aromatic compound is preferably used as a dopant material in the light-emitting layer because it has an excellent fluorescence quantum yield.

[0157] The present invention will be described below with reference to examples, but the present invention is not limited to the following examples. In the following examples and comparative examples, compounds G-1, G-2, G-101 to G-103 are the compounds shown below.

[0158]

[0159] The evaluation methods for structural analysis in the examples and comparative examples are as follows.

[0160] <Measurement of Fluorescence Spectrum> The fluorescence spectrum of the compound was measured using an F-2500 spectrofluorometer (Hitachi, Ltd.). -5 The compound was dissolved at a concentration of 100 mol / L, and the fluorescence spectrum was measured when excited at a wavelength of 460 nm.

[0161] <Measurement of luminescence quantum yield> The luminescence quantum yield of a compound was measured using an absolute PL quantum yield measurement device (Quantaurus-QY, manufactured by Hamamatsu Photonics K.K.). The compound was dissolved in toluene at a concentration of 1 × 10 -5 The compound was dissolved at a concentration of 1 mol / L, and the luminescence quantum yield was measured when excited at a wavelength of 460 nm.

[0162] (HOMO Level) In calculating the HOMO levels of the compounds, the structures of the compounds of each Example and Comparative Example were optimized in the 6-31G(d) basis set using the B3LYP density functional theory in the general-purpose quantum chemistry calculation program "Gaussian 16" program package (manufactured by Gaussian Corporation). Based on the optimized structures, the HOMO levels were calculated in the 6-311++G(d,p) basis set using the B3LYP density functional theory.

[0163] Synthesis Example 1 A method for synthesizing Compound G-1 of Synthesis Example 1 of the present invention will be described below.

[0164]

[0165] In the synthesis method for compound G-1, a flask containing 2-bromo-1,3-difluorobenzene (2.0 g), dipyridylcarbazole (10.0 g), potassium carbonate (5.0 g), and N-methyl-2-pyrrolidone (25 mL) was heated and stirred at 170°C for 10 hours under a nitrogen atmosphere. Hereinafter, N-methyl-2-pyrrolidone will be abbreviated as NMP. After the reaction of the solution in the flask was stopped, the reaction solution in the flask was cooled to room temperature, and water and toluene were added, and the reaction solution was separated into an organic solvent layer and an aqueous layer. The solvent was distilled off from the organic solvent layer under reduced pressure, and the resulting mixture was purified by silica gel column chromatography to obtain intermediate 1A.

[0166] A flask containing Intermediate 1A (10.0 g) and xylene (30 mL) was cooled to -40°C, and a 2.6 M n-butyllithium hexane solution (4.0 mL) was added dropwise. After the dropwise addition was completed, the solution in the flask was warmed to room temperature and then cooled to -40°C again, and boron tribromide (1.1 mL) was added to the solution. Next, the solution in the flask was warmed to room temperature and stirred for 13 hours, then cooled to 0°C. N,N-diisopropylethylamine (3.1 mL) was then added to the solution in the flask, and the mixture was heated and stirred at 130°C for 5 hours. The reaction solution after the reaction in the flask was cooled to room temperature, and an aqueous sodium acetate solution cooled in an ice bath was added and stirred. The stirred reaction solution was subjected to suction filtration to collect the precipitated solid. The obtained solid was washed with water, methanol, and then heptane, and further recrystallized from chlorobenzene to obtain the target compound G-1 (0.8 g).

[0167] Compounds G-2, G-101 to G-103 other than those mentioned above can also be synthesized by changing various raw materials.

[0168] In the following examples and comparative examples, a backlight unit including each color conversion sheet, a blue LED element (emission peak wavelength: 445 nm), and a light guide plate was laminated with the color conversion sheet on one side of the light guide plate and a prism sheet on the color conversion sheet, and then current was passed through it to light up the blue LED element, and the initial light emission characteristics were measured using a spectroradiometer (CS-1000, manufactured by Konica Minolta). Note that when measuring the initial light emission characteristics, the color conversion sheet was not inserted, and the brightness of the light from the blue LED element was 800 cd / m 2 Thereafter, light from a blue LED element was continuously irradiated at room temperature, and the time until the luminance decreased by 5% was observed to evaluate the light durability.

[0169] Example 1-1 of the present invention is an example in which the polycyclic aromatic compound according to the above-described embodiment was used as a light-emitting material (color-changing material). In this Example 1-1, an acrylic resin was used as the binder resin, and 0.25 parts by weight of compound G-1 as the light-emitting material and 400 parts by weight of toluene as the solvent were mixed with 100 parts by weight of this acrylic resin. Thereafter, this mixture was stirred and degassed for 20 minutes at 300 rpm using a planetary stirring and degassing device "Mazerustar KK-400" (manufactured by Kurabo Industries, Ltd.), thereby obtaining a color-changing composition.

[0170] Similarly, a polyester resin was used as the binder resin, and 100 parts by weight of this polyester resin was mixed with 300 parts by weight of toluene as a solvent. Thereafter, this solution was stirred and degassed for 20 minutes at 300 rpm using a planetary stirring and degassing device "Mazerustar KK-400" (manufactured by Kurabo Industries, Ltd.), thereby obtaining an adhesive composition.

[0171] Next, the color-changing composition obtained as described above was applied onto a first substrate layer, "Lumirror" U48 (manufactured by Toray Industries, Inc., thickness 50 μm), using a slit die coater, and heated at 100°C for 20 minutes and dried to form an (A) layer with an average film thickness of 16 μm.

[0172] Similarly, the adhesive composition obtained as described above was applied to the PET substrate layer side of the light diffusion film "Chemical Matte" 125PW (manufactured by Kimoto Co., Ltd., thickness 138 μm), which was the second substrate layer, using a slit die coater, and heated and dried at 100°C for 20 minutes to form a (B) layer with an average film thickness of 48 μm.

[0173] Next, these two layers (A) and (B) were heated and laminated so that the color conversion layer of layer (A) and the adhesive layer of layer (B) were directly laminated to produce a color conversion sheet with a layered structure of "first base layer / color conversion layer / adhesive layer / second base layer / light diffusion layer."

[0174] When this color conversion sheet was continuously irradiated with light from a blue LED element at room temperature, the time required for the luminance to decrease by 5% was 1010 hours. The luminescent material of Example 1-1 and the evaluation results are shown in Table 1 below.

[0175] (Example 1-2 and Comparative Examples 1-1 to 1-3) In Example 1-2 of the present invention and Comparative Examples 1-1 to 1-3 for the present invention, color conversion sheets were produced and evaluated in the same manner as in Example 1-1, except that compounds (compounds G-2, G-101 to G-103) shown in Table 1 below were used as appropriate as the luminescent material. The luminescent materials and evaluation results of Example 1-2 and Comparative Examples 1-1 to 1-3 are shown in Table 1. The longer the light durability, the more preferable, and specifically, 500 hours or more is preferable.

[0176]

[0177] The present invention will be described below with reference to examples, but the present invention is not limited to the following examples. In the following examples and comparative examples, compounds G-3 to G-8 and G-104 to G-107 are the compounds shown below.

[0178]

[0179]

[0180] The evaluation methods for structural analysis in the examples and comparative examples are as follows.

[0181] <Measurement of Fluorescence Spectrum> The fluorescence spectrum of the compound was measured using an F-2500 spectrofluorometer (Hitachi, Ltd.). -5 The compound was dissolved at a concentration of 100 mol / L, and the fluorescence spectrum was measured when excited at a wavelength of 460 nm.

[0182] <Measurement of luminescence quantum yield> The luminescence quantum yield of a compound was measured using an absolute PL quantum yield measurement device (Quantaurus-QY, manufactured by Hamamatsu Photonics K.K.). The compound was dissolved in toluene at a concentration of 1 × 10 -5 The compound was dissolved at a concentration of 1 mol / L, and the luminescence quantum yield was measured when excited at a wavelength of 460 nm.

[0183] Synthesis Example 2 A method for synthesizing Compound G-3 of Synthesis Example 2 of the present invention will be described below.

[0184]

[0185] In the synthesis method of compound G-3, a flask containing 2-bromo-1,3-difluorobenzene (20.0 g), carbazole (50.0 g), potassium carbonate (50.0 g), and NMP (250 mL) was heated and stirred at 170°C for 10 hours under a nitrogen atmosphere. After the reaction of the solution in the flask was stopped, the reaction solution in the flask was cooled to room temperature, and water and toluene were added, and the reaction solution was separated into an organic solvent layer and an aqueous layer. The solvent was distilled off from the organic solvent layer under reduced pressure, and the residue was purified by silica gel column chromatography to obtain intermediate 3A.

[0186] A flask containing Intermediate 3A (44.2 g) and xylene (300 mL) was cooled to -40°C, and a 2.6 M n-butyllithium hexane solution (40.4 mL) was added dropwise. After the dropwise addition was completed, the solution in the flask was warmed to room temperature and then cooled again to -40°C, and boron tribromide (10.2 mL) was added to the solution. Next, the solution in the flask was warmed to room temperature and stirred for 13 hours, then cooled to 0°C. N,N-diisopropylethylamine (30.8 mL) was then added to the solution in the flask, and the mixture was heated and stirred at 130°C for 5 hours. The reaction solution after the reaction in the flask was cooled to room temperature, and an aqueous sodium acetate solution cooled in an ice bath was added and stirred. The stirred reaction solution was subjected to suction filtration to collect the precipitated solid. The obtained solid was washed with water, methanol, and then heptane, and further recrystallized from chlorobenzene to obtain Intermediate 3B.

[0187] Dimethylformamide (10 mL) and dichloroethane (200 mL) were mixed in a flask, and the mixture was cooled to 0°C. POCl (10 mL) was slowly added dropwise to the cooled mixture under a nitrogen atmosphere, and the solution in the flask was stirred at room temperature for 30 minutes. Intermediate 3B (10 g) was added to the stirred reaction solution, which was then heated to 60°C and stirred for 1 hour. The solution of Intermediate 3B was cooled to room temperature and then poured into a mixture of ice and saturated aqueous sodium hydroxide. The mixture was stirred at room temperature for 2 hours, and the organic solvent layer was extracted with chloroform. The resulting organic solvent layer was dried over anhydrous magnesium sulfate, filtered, and distilled under reduced pressure to remove the solvent from the organic solvent layer. Intermediate 3C was then obtained by passing through a silica gel column.

[0188] Intermediate 3C (6.0 g) and NHSOH (1.2 g) were dissolved in tetrahydrofuran, and then NaClO (1.1 g) dissolved in water was slowly added dropwise to the solution at 0°C. The resulting solution was stirred at room temperature for 1 hour, and then saturated NaSO solution was added to the solution. An organic solvent layer was then extracted from the mixture with chloroform. The resulting organic solvent layer was dried over anhydrous magnesium sulfate, filtered, and the solvent was removed from the organic solvent layer by distillation under reduced pressure. The mixture was then passed through a silica gel column to obtain Intermediate 3D.

[0189] Intermediate 3E (5.0 g), phenol (1.0 g), and DMAP (0.1 g) were dissolved in dichloromethane, and then DCC (2.2 g) dissolved in dichloromethane was slowly added dropwise to the solution at 0°C. The resulting solution was stirred at room temperature for 12 hours, and then saturated sodium hydroxide solution was added to the solution. An organic solvent layer was then extracted from the mixture with chloroform. The resulting organic solvent layer was dried over anhydrous magnesium sulfate, filtered, and the solvent was removed from the organic solvent layer by distillation under reduced pressure. The mixture was then passed through a silica gel column to obtain the target compound G-3 (4.3 g).

[0190] Compounds G-4 to G-8 and G-104 to G-107 other than those mentioned above can also be synthesized by changing various raw materials.

[0191] In the following examples and comparative examples, a backlight unit including each color conversion sheet, a blue LED element (emission peak wavelength: 445 nm), and a light guide plate was laminated with the color conversion sheet on one side of the light guide plate and a prism sheet on the color conversion sheet, and then current was passed through it to light up the blue LED element, and the initial light emission characteristics were measured using a spectroradiometer (CS-1000, manufactured by Konica Minolta). Note that when measuring the initial light emission characteristics, the color conversion sheet was not inserted, and the brightness of the light from the blue LED element was 800 cd / m 2 Thereafter, light from a blue LED element was continuously irradiated at room temperature, and the time until the luminance decreased by 5% was observed to evaluate the light durability.

[0192] Example 2-1 Example 2-1 of the present invention is an example in which the polycyclic aromatic compound according to the above-described embodiment was used as a light-emitting material (color-changing material). In this Example 2-1, an acrylic resin was used as the binder resin, and 0.25 parts by weight of compound G-3 as the light-emitting material and 400 parts by weight of toluene as the solvent were mixed with 100 parts by weight of this acrylic resin. Thereafter, this mixture was stirred and degassed for 20 minutes at 300 rpm using a planetary stirring and degassing device "Mazerustar KK-400" (manufactured by Kurabo Industries, Ltd.), thereby obtaining a color-changing composition.

[0193] Similarly, a polyester resin was used as the binder resin, and 100 parts by weight of this polyester resin was mixed with 300 parts by weight of toluene as a solvent. Thereafter, this solution was stirred and degassed for 20 minutes at 300 rpm using a planetary stirring and degassing device "Mazerustar KK-400" (manufactured by Kurabo Industries, Ltd.), thereby obtaining an adhesive composition.

[0194] Next, the color-changing composition obtained as described above was applied onto a first substrate layer, "Lumirror" U48 (manufactured by Toray Industries, Inc., thickness 50 μm), using a slit die coater, and heated at 100°C for 20 minutes and dried to form an (A) layer with an average film thickness of 16 μm.

[0195] Similarly, the adhesive composition obtained as described above was applied to the PET substrate layer side of the light diffusion film "Chemical Matte" 125PW (manufactured by Kimoto Co., Ltd., thickness 138 μm), which was the second substrate layer, using a slit die coater, and heated and dried at 100°C for 20 minutes to form a (B) layer with an average film thickness of 48 μm.

[0196] Next, these two layers (A) and (B) were heated and laminated so that the color conversion layer of layer (A) and the adhesive layer of layer (B) were directly laminated to produce a color conversion sheet with a layered structure of "first base layer / color conversion layer / adhesive layer / second base layer / light diffusion layer."

[0197] When light from a blue LED element (blue light) was color converted using this color conversion sheet, high-color-purity green light emission was obtained with a peak wavelength of 527 nm and a half-width of the emission spectrum at the peak wavelength of 28 nm, when only the green light emission region was extracted. The luminescence quantum yield was 0.95. Furthermore, when continuously irradiated with light from a blue LED element at room temperature, the time required for the luminance to decrease by 5% was 810 hours. The luminescent material and evaluation results of Example 2-1 are shown in Table 2 below.

[0198] (Examples 2-2 to 2-6 and Comparative Examples 2-1 to 2-4) In Examples 2-2 to 2-6 of the present invention and Comparative Examples 2-1 to 2-4 for the present invention, color conversion sheets were produced and evaluated in the same manner as in Example 2-1, except that compounds (compounds G-4 to G-8, G-104 to G-107) shown in Table 2 below were used as the luminescent material. The luminescent materials and evaluation results of Examples 2-2 to 2-6 and Comparative Examples 2-1 to 2-4 are shown in Table 2. The longer the light durability, the more preferable, and specifically, 800 hours or more is preferable.

[0199]

[0200] As described above, the polycyclic aromatic compound, color-converting composition, color-converting sheet, light source unit, display, and lighting device according to the present invention are suitable for achieving both improved color reproducibility and high durability.

[0201] 1A, 1B, 1C, 1D Color conversion sheet 10 Base layer 11 Color conversion layer 12 Barrier film

Claims

1. A compound that exhibits light emission with a peak wavelength observed in a region of 500 nm or more and 750 nm or less by using excitation light, has a HOMO level of -6.0 eV or less, and emits delayed fluorescence, and is represented by general formula (1) or general formula (2). A polycyclic aromatic compound characterized in that 【Chemistry 1】 (Ring Za, ring Zb and ring Zc are each independently a substituted or unsubstituted aryl ring having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroaryl ring having 6 to 30 ring carbon atoms. Z 1 and Z 2 are each independently an oxygen atom, NRa (nitrogen atom having a substituent Ra) or a sulfur atom. When Z 1 is NRa, the substituent Ra may be bonded to ring Za or ring Zb to form a ring. When Z 2 is NRa, the substituent Ra may be bonded to ring Za or ring Zc to form a ring. E is a boron atom, a phosphorus atom, SiRa (silicon atom having a substituent Ra) or P═O. E 1 and E 2 are each independently BRa (boron atom having a substituent Ra), PRa (phosphorus atom having a substituent Ra), SiRa 2 (silicon atom having two substituents Ra), P(═O)Ra 2 (phosphine oxide having two substituents Ra) or P(=S)Ra 2 (phosphine sulfide having two substituents Ra), S(=O) or S(=O) 2. When E 1 is BRa, PRa, SiRa 2 , P(=O)Ra 2 or P(=S)Ra 2 , the substituent Ra may be bonded to ring Za or ring Zb to form a ring. When E 2 is BRa, PRa, SiRa 2 , P(=O)Ra 2 or P(=S)Ra 2 , the substituent Ra may be bonded to ring Za or ring Zc to form a ring. Each of the substituents Ra is independently a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, or a substituted or unsubstituted alkyl group.)

2. The HOMO level of the polycyclic aromatic compound is −6.2 eV or less. The polycyclic aromatic compound according to claim 1 .

3. The HOMO level of the polycyclic aromatic compound is −6.5 eV or less. The polycyclic aromatic compound according to claim 1 .

4. The half-width of the emission spectrum at the emission peak wavelength of the polycyclic aromatic compound is 40 nm or less. The polycyclic aromatic compound according to claim 1 .

5. The compound represented by the general formula (1) or the general formula (2) has at least one electron-withdrawing group. The polycyclic aromatic compound according to claim 1 .

6. The compound represented by the general formula (1) or the general formula (2) has two or more electron-withdrawing groups, The polycyclic aromatic compound according to claim 5 .

7. The electron-withdrawing group is a cyano group, an acyl group, an ester group, an amide group, a sulfonyl group, a sulfonate ester group, or a sulfonamide group; The polycyclic aromatic compound according to claim 5 .

8. The electron withdrawing group is an ester group. The polycyclic aromatic compound according to claim 5 .

9. Said Z 1 and Z 2 is an oxygen atom or NRa; The polycyclic aromatic compound according to claim 1 .

10. E is a boron atom; The above E 1 and the above E 2 is BRa, The polycyclic aromatic compound according to claim 1 .

11. the ring Za, the ring Zb and the ring Zc are benzene rings; The polycyclic aromatic compound according to claim 1 .

12. The polycyclic aromatic compound exhibits light emission having a peak wavelength observed in a region of 500 nm or more and less than 580 nm when excited with excitation light. The polycyclic aromatic compound according to claim 1 .

13. The polycyclic aromatic compound exhibits light emission having a peak wavelength observed in a range of 580 nm or more and 750 nm or less when excited with excitation light. The polycyclic aromatic compound according to claim 1 .

14. A color conversion composition that converts incident light into light different from the incident light, A polycyclic aromatic compound according to any one of claims 1 to 13, A binder resin; A color changing composition comprising:

15. A color conversion sheet that converts incident light into light different from the incident light, A polycyclic aromatic compound according to any one of claims 1 to 13, A binder resin; A color conversion sheet comprising:

16. Further comprising a barrier film, The color conversion sheet according to claim 15 .

17. A light source; The color conversion sheet according to claim 15; A light source unit comprising:

18. The light source is a light emitting diode having a maximum emission in the wavelength range of 430 nm or more and 500 nm or less.

18. The light source unit according to claim 17.

19. The color conversion sheet according to claim 15, A display characterized by:

20. The color conversion sheet according to claim 15, A lighting device characterized by:

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