WO2020189519A1 - Élément électroluminescent organique et composé - Google Patents

Élément électroluminescent organique et composé Download PDF

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WO2020189519A1
WO2020189519A1 PCT/JP2020/010890 JP2020010890W WO2020189519A1 WO 2020189519 A1 WO2020189519 A1 WO 2020189519A1 JP 2020010890 W JP2020010890 W JP 2020010890W WO 2020189519 A1 WO2020189519 A1 WO 2020189519A1
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organic
layer
general formula
perovskite
group
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PCT/JP2020/010890
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Japanese (ja)
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敏則 松島
マシュー ライアン ライデン
センコウ シン
サンガランゲ ドン アトゥラ サンダナヤカ
安達　千波矢
ファブリス マトベ
デビッド クレア
テン テン
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国立大学法人九州大学
ソルボンヌ・ユニヴェルシテ
サントル ナシオナル ドゥ ラ ルシェルシュ シアンティフィーク
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Priority to JP2021507287A priority Critical patent/JPWO2020189519A1/ja
Publication of WO2020189519A1 publication Critical patent/WO2020189519A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D285/00—Heterocyclic compounds containing rings having nitrogen and sulfur atoms as the only ring hetero atoms, not provided for by groups C07D275/00 - C07D283/00
    • C07D285/01—Five-membered rings
    • C07D285/02—Thiadiazoles; Hydrogenated thiadiazoles
    • C07D285/14—Thiadiazoles; Hydrogenated thiadiazoles condensed with carbocyclic rings or ring systems
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D417/00—Heterocyclic compounds containing two or more hetero rings, at least one ring having nitrogen and sulfur atoms as the only ring hetero atoms, not provided for by group C07D415/00
    • C07D417/14—Heterocyclic compounds containing two or more hetero rings, at least one ring having nitrogen and sulfur atoms as the only ring hetero atoms, not provided for by group C07D415/00 containing three or more hetero rings
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
    • C09K11/66—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing germanium, tin or lead
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B33/00—Electroluminescent light sources
    • H05B33/12—Light sources with substantially two-dimensional radiating surfaces
    • H05B33/14—Light sources with substantially two-dimensional radiating surfaces characterised by the chemical or physical composition or the arrangement of the electroluminescent material, or by the simultaneous addition of the electroluminescent material in or onto the light source
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K50/00—Organic light-emitting devices
    • H10K50/80—Constructional details
    • H10K50/84—Passivation; Containers; Encapsulations
    • H10K50/844—Encapsulations
    • H10K50/8445—Encapsulations multilayered coatings having a repetitive structure, e.g. having multiple organic-inorganic bilayers

Definitions

  • the present invention relates to an organic electroluminescence device having a perovskite film and a compound useful as a material for the perovskite film.
  • organic electroluminescence device is a light emitting device that utilizes the radiation deactivation of a current-excited organic light emitting material for light emission, and research to improve its light emitting efficiency is being actively conducted.
  • the excited singlet state and the excited triplet state are formed with a probability of 25:75, but the transition from the excited triplet state to the ground singlet state is a forbidden transition. Therefore, in a normal fluorescent material, the excited triplet state loses energy due to thermal radiation, and only the energy of the excited singlet state formed with a probability of 25% is effectively used for light emission. For this reason, the conventional organic EL element using a fluorescent material has a limit in improving the luminous efficiency.
  • the TADF material is a light emitting material capable of causing an inverse intersystem crossing from an excited triplet state to an excited singlet state, and light emission is obtained by radiation deactivation of the excited singlet state formed through such an intersystem crossing.
  • the excited triplet energy is effectively used for light emission. Therefore, by using the TADF material, it is possible to greatly improve the external quantum efficiency of the organic EL device.
  • the reality is that useful and practical TADF materials are limited, and it is desired to provide a technique that can be used for light emission by forming an excited singlet state with a high probability by a completely different approach.
  • the present inventors have made diligent studies to improve the luminous efficiency of the organic EL element by a completely new concept while using perovskite.
  • Non-Patent Documents 1 and 2 do not show any intention or suggestion to transfer the energy generated in the inorganic layer to the organic layer. The present invention has been proposed based on these findings, and specifically has the following configuration.
  • An organic electroluminescence element having a pair of electrodes and a perovskite film formed between the pair of electrodes. In the perovskite film, inorganic layers and organic layers containing organic molecules are alternately arranged.
  • An organic electroluminescence element having the above-mentioned structure and satisfying the relationship represented by the following formula (A) between the inorganic layer and the organic layer. Equation (A) Eg (O)> Eg (I)> E S1 (O) [In the formula (A), Eg (O) represents the energy gap between the HOMO and LUMO of the organic layer, and Eg (I) represents the band gap between the valence band and the conduction band of the inorganic layer.
  • ES1 (O) represents the lowest excited single-term energy level of the organic layer.
  • the inorganic layer is formed along a direction perpendicular to the facing surfaces of the pair of electrodes, and the organic molecules are oriented in the horizontal direction with respect to the facing surfaces of the pair of electrodes [1].
  • the perovskite film is formed of a perovskite-type compound represented by the following general formula (1b), and a divalent organic cation represented by A 4 of the following general formula (1b) forms the organic molecule.
  • the organic electroluminescence device according to [1] or [2].
  • a part of the methylene group constituting the alkylene group may be substituted with —O—.
  • M 1 and M 2 each independently represent a cationic group.
  • [5] The organic electroluminescence device according to [4], wherein Ar of the general formula (7) contains a benzothiadiazole ring.
  • [6] The organic electroluminescence device according to any one of [1] to [5], wherein the organic molecule is a fluorescent organic molecule.
  • the organic electroluminescence device of the present invention carriers are efficiently injected and transported into the inorganic layer by satisfying a predetermined energy relationship between the inorganic layer and the organic layer constituting the perovskite film, and the carrier is transported by the inorganic layer.
  • the energy generated by the recombination efficiently transfers to the lowest excited single-term energy level of the organic molecule. As a result, many excited singlet states are formed in the organic layer, and high luminous efficiency is exhibited.
  • FIG. 5 is an energy level diagram showing a preferable energy relationship between an inorganic layer and an organic layer of a perovskite film possessed by the organic electroluminescence device of the present invention. It is a schematic diagram which shows an example of the perovskite film which the organic electroluminescence element of this invention has. It is the schematic sectional drawing which shows the layer structure example of the organic electroluminescence element. It is the absorption spectrum of the BTAPbBr 4 perovskite membrane, the BTABr 2 membrane and the PbBr 2 membrane. It is the excitation spectrum at the emission wavelength of the BTAPbBr 4 perovskite film and the BTABr 2 film.
  • FIG. 2 It is an emission spectrum of the BTAPbBr 4 perovskite film and the BTABr 2 film. It is a schematic diagram which shows the orientation state of the organic molecule in the BTC6 film formed in the comparative example 1.
  • FIG. It is a schematic diagram showing the alignment state of the formation direction and organic molecules of the inorganic layer of PEAPbBr 4 perovskite film formed in Comparative Example 2.
  • the contents of the present invention will be described in detail below.
  • the description of the constituent elements described below may be based on typical embodiments and specific examples of the present invention, but the present invention is not limited to such embodiments and specific examples.
  • the numerical range represented by using "-" in the present specification means a range including the numerical values before and after "-" as the lower limit value and the upper limit value.
  • the term "main component” in the present specification means the component having the highest content among the constituent components.
  • the isotope species of hydrogen atoms existing in the molecule of the compound used in the present invention is not particularly limited, and for example, all hydrogen atoms in the molecule may be 1 H, or some or all may be 2 H. It may be [deuterium D].
  • the organic electroluminescence device of the present invention has a pair of electrodes and a perovskite film formed between the pair of electrodes.
  • the perovskite film has a structure in which inorganic layers and organic layers containing organic molecules are alternately arranged, and the inorganic layers and the organic layers satisfy a predetermined energy relationship.
  • the organic electroluminescence device of the present invention exhibits high luminous efficiency by having such a configuration.
  • the layer structure of the perovskite film and the device included in the organic electroluminescence device of the present invention will be described in detail.
  • the perovskite film contained in the electroluminescence element of the present invention has a structure in which inorganic layers and organic layers containing organic molecules are alternately arranged. Then, the inorganic layer and the organic layer satisfy the relationship represented by the following formula (A). Equation (A) Eg (O)> Eg (I)> E S1 (O) [In the formula (A), Eg (O) represents the energy gap between the HOMO and LUMO of the organic layer, and Eg (I) represents the band gap between the valence band and the conduction band of the inorganic layer. ES1 (O) represents the lowest excited single-term energy level of the organic layer.
  • An organic electroluminescence device having such a perovskite film can obtain a significantly higher luminous efficiency than an organic electroluminescence device using a normal organic light emitting layer. It is presumed that this is because carrier recombination occurs efficiently in the inorganic layer, and the energy generated by the carrier recombination efficiently moves to the organic layer and is effectively used for fluorescence emission. ..
  • the light emitting mechanism will be described with reference to FIG.
  • the energy relationship shown in FIG. 1 schematically shows a typical example, and the energy relationship of the perovskite film that can be used in the present invention is not limited to that shown in FIG.
  • singlet excitons and triplet excitons are 25: 1 according to the spin statistical law due to the recombination of holes and electrons injected into the organic light emitting layer. It is formed with a formation probability of 75.
  • the singlet-excited state emits fluorescence when inactivated to the basal singlet state, but the triplet-excited state loses energy due to thermal radiation because the transition to the basal singlet state is a forbidden transition. It will be deactivated without radiation. Therefore, the energy of triplet excitons having a high formation probability cannot be effectively used for light emission, and the light emission efficiency becomes low.
  • the organic electroluminescence element of the present invention has a perovskite film having an inorganic layer and an organic layer, and as shown in FIG. 1A, the energy of the organic layers arranged on both sides of the inorganic layer.
  • the gap Eg (O) is wider than the band gap Eg (I) of the inorganic layer (Eg (O)> Eg (I)). Therefore, the carriers that have reached the perovskite film are more likely to be injected into the inorganic layer than the organic layer, and the carriers are efficiently transported in the inorganic layer due to the high carrier mobility. Finally, an excited state is formed by recombination of electrons and holes in the inorganic layer.
  • FIG. 1A the energy of the organic layers arranged on both sides of the inorganic layer.
  • the gap Eg (O) is wider than the band gap Eg (I) of the inorganic layer (Eg (O)> Eg (I)). Therefore, the carriers that have reached the perovskite film are more likely to
  • the lowest excited singlet energy level E S1 organic layer (O) is smaller than the band gap Eg of the inorganic layer (I) (Eg (I) > E S1 ( O)).
  • the Felster-type transfer to the excited singlet energy level ES1 (O) is more important than the Dexter-type transfer to the excited triplet energy level ET1 (O). Is more likely to occur. Therefore, most of the energy released by the band-to-band transition in the inorganic layer is transferred to the excited single-term energy level ES1 (O) of the organic layer.
  • the organic electroluminescence device of the present invention can realize high external quantum efficiency.
  • the fact that there is energy transfer from the inorganic layer to the organic layer means that when the emission spectrum of the target perovskite film is measured, the emission peak derived from the organic molecule of the organic layer is derived from the exciton of the inorganic layer. Confirmed by observing at an emission intensity much higher than the emission peak and by observing a peak (exciton peak) derived from excitons in the inorganic layer when the excitation spectrum of the target perovskite film is measured. can do. It should be noted that the emission peak derived from the organic molecule can be determined by recognizing a similar emission peak in the same wavelength range in the emission spectrum of the organic layer formed only by the organic molecule. Further, the peak derived from the exciton of the inorganic layer can be determined by the extremely small half-value width.
  • the energy generated in the inorganic layer and transferred to the organic layer includes the energy of singlet excitons formed in the carrier recombination process in addition to the energy released by the interband transition.
  • the "singlet exciton" formed in the inorganic layer may be a singlet exciton directly formed by rearrangement of carriers, and further, from an excited triplet state to an excited singlet state. It may contain singlet excitons formed by inverse intersystem crossing. Inorganic layers with a perovskite structure are prone to such inverse intersystem crossings because the difference between the lowest excited singlet energy level and the lowest excited triplet energy level is very small, which causes many excited singlet states. It can be formed and transferred to the organic layer.
  • the energy gap Eg (O) between the HOMO (Highest Occupied Molecular Orbital) and LUMO (Lowest Unoccupied Molecular Orbital) of the organic layer is the upper end VB of the valence band of the inorganic layer.
  • the band gap Eg (I) between the and the lower end CB of the conduction band carriers can be injected and transported more efficiently in the inorganic layer than in the organic layer.
  • the difference (Eg (O) -Eg (I)) between the energy gap Eg (O) of the organic layer and the band gap Eg (I) of the inorganic layer is preferably 0.01 to 2 eV.
  • the upper end VB of the valence band of the inorganic layer can be obtained by photoelectron spectroscopy, and the lower end CB of the conduction band can be obtained by back photoelectron spectroscopy.
  • the energy level of HOMO in the organic layer can be determined by photoelectron spectroscopy, and the energy level of LUMO can be determined by back-photoelectron spectroscopy.
  • the bandgap Eg (I) of the inorganic layer corresponds to the energy released by the interband transition (bandgap energy Ex).
  • the perovskite film used in the present invention has a bandgap energy generated in the inorganic layer because the lowest excited single-state energy level ES1 (O) of the organic layer is lower than the bandgap Eg (I) of the inorganic layer. It can be efficiently transferred to the lowest excited single-term energy level ES1 (O) of the organic layer.
  • the band gap Eg of the inorganic layer (I) the difference between the lowest excited singlet energy level E S1 organic layer (O) (Eg (I) -E S1 (O)) is zero.
  • the lowest excited singlet energy level E S1 of the organic layer the difference between (O) and the lowest excited triplet energy level E T1 (O) (E S1 (O) -E T1 (O)) is zero. It is preferably 01 to 2 eV, more preferably 0.01 to 1 eV, and even more preferably 0.01 to 0.5 eV.
  • ES1 (O), and ET1 (O) can be obtained from the emission spectrum. If it is difficult to estimate ET1 (O) at room temperature, the phosphorescence spectrum may be measured at low temperature.
  • the "perovskite film” in the present invention means a film having a perovskite-type crystal structure, and an inorganic skeleton in which octahedral structures composed of inorganic ions are connected by sharing vertices and organic ions arranged outside the inorganic skeleton. Consists of.
  • the "inorganic layer” in the present invention means a layer formed by inorganic ions among the ions constituting the perovskite type crystal structure.
  • the "inorganic layer” is formed by a layer of inorganic skeletons in which the octahedrons of perovskite-type crystals are arranged in a two-dimensional manner.
  • the number of layers of the inorganic skeleton constituting each inorganic layer may be one layer or two or more layers. When the number of layers of the inorganic skeleton is two or more, small organic ions or cesium ions may be arranged at the boundary of each layer.
  • the number of layers of the inorganic skeleton constituting each inorganic layer is preferably 1 to 100, more preferably 1 to 50, and even more preferably 1 to 10.
  • the "organic layer” in the present invention is a layer containing an organic molecule having a cationic group.
  • the number of cationic groups contained in the organic molecule may be one or two or more, but it is preferably one or two, and more preferably two.
  • the organic molecule has two or more cationic groups, the cationic groups may be the same or different from each other, but are preferably the same.
  • a compound represented by the general formula (7) described in the column of (compound represented by the general formula (1b)) below can be mentioned.
  • the perovskite film of the organic electroluminescence device of the present invention has a structure in which inorganic layers and organic layers containing organic molecules are alternately arranged.
  • the organic layer is preferably formed by orienting organic molecules in a specific direction between the inorganic layers.
  • the inorganic layer may be formed along the horizontal direction with respect to the facing surfaces of the pair of electrodes, or may be formed along the vertical direction, but may be formed along the direction perpendicular to the facing surfaces of the pair of electrodes. It is preferably formed. Further, when the inorganic layer is formed along the direction perpendicular to the facing surfaces of the pair of electrodes, it is preferable that the organic molecules are oriented in the horizontal direction with respect to the facing surfaces of the pair of electrodes.
  • the fact that the inorganic layer is "formed along the direction perpendicular to the facing surfaces of the pair of electrodes” means that the inorganic layer (a layer in which the inorganic skeletons constituting the octahedron are two-dimensionally arranged) is in other words. It means that the pair of electrodes are arranged so as to stand up in the direction perpendicular to the facing surfaces.
  • the direction in which the inorganic layer rises with respect to the facing surface of the electrode may be referred to as the "inorganic layer forming direction”.
  • the formation direction of the inorganic layer can be confirmed by X-ray structural analysis.
  • the organic molecule is "horizontally oriented with respect to the facing surfaces of the pair of electrodes" means that the long axis of the organic molecule is along the horizontal direction with respect to the facing surfaces of the pair of electrodes.
  • the cationic group of the organic molecule is arranged outside the inorganic layer, and the long axis of the molecule is oriented along the horizontal direction with respect to the facing surfaces of the pair of electrodes.
  • the direction of the long axis of the organic molecule with respect to the electrode facing surface can be confirmed by X-ray structural analysis.
  • the organic layer is preferably composed only of organic molecules oriented in the horizontal direction, but may contain organic molecules whose major axis is not oriented in the horizontal direction.
  • the "opposing surface of a pair of electrodes” means a facing surface of one electrode with respect to the other electrode (hereinafter, referred to as “electrode facing surface”).
  • electrode facing surface The reference for the “vertical direction” and the “horizontal direction” may be the facing surfaces of at least one of the electrodes. That is, in the above preferred configuration, the inorganic layer need only be arranged perpendicular to the facing surface of at least one electrode, and the organic molecules are oriented horizontally with respect to the facing surface of at least one electrode. Just do it.
  • vertical as used herein means that the angle between the pair of electrodes and the facing surfaces is 90 ° ⁇ 20 °, preferably 90 ° ⁇ 10 °, more preferably 90 ° ⁇ 5 °. is there. “Horizontal” means that the angle of the pair of electrodes with the facing surfaces is 0 ° ⁇ 20 °, preferably 0 ° ⁇ 10 °, more preferably 0 ° ⁇ 5 °.
  • the perovskite film in which the inorganic layer is formed along the direction perpendicular to the electrode facing surface and the organic molecules are oriented in the horizontal direction with respect to the electrode facing surface is the type of perovskite type compound used for forming the perovskite film, the constituent element species, and the organic molecule. It can be obtained by controlling the structure, the formation conditions of the perovskite film, and the like.
  • FIG. 2 shows a preferable example of the perovskite film provided in the organic electroluminescence device of the present invention.
  • FIG. 2 schematically shows an example of a perovskite film, and the structure of the perovskite film used in the present invention should not be construed as being limited by the structure shown in FIG.
  • 21 represents one of a pair of electrodes
  • 22 represents a perovskite film
  • 23 represents an inorganic layer
  • 24 represents an organic layer
  • 24a represents an organic molecule.
  • the inorganic layer 23 is formed so as to rise in a direction perpendicular to one surface (opposing surface of the pair of electrodes) 21a of the electrodes 21, and the organic molecules 24a constituting the organic layer 24 are formed. , Each of which is oriented in the horizontal direction with respect to one surface 21a of the electrode 21.
  • the perovskite film used in the present invention has an inorganic layer and an organic layer satisfying the above formula (A), and the inorganic layer is formed along the direction perpendicular to the facing surface of the pair of electrodes.
  • the organic molecules in the organic layer are oriented in the horizontal direction with respect to the facing surfaces of the pair of electrodes, the following effects can also be obtained.
  • the carriers injected into the inorganic layer are efficiently transported in the inorganic layer due to its high carrier mobility.
  • the forming direction of the inorganic layer is perpendicular to the electrode facing surface, the forming direction of the inorganic layer and the direction of the electric field match, so that the carriers are more efficiently formed along the forming direction of the inorganic layer. It will be transported and carrier recombination will occur more efficiently. Further, in the perovskite film satisfying the formula (A), the energy generated by the carrier recombination in the inorganic layer is transferred to the excited singlet energy level ES1 (O) of the organic molecule, and the organic molecule is radiated inactivated. To do.
  • the inorganic layer is formed along the direction perpendicular to the facing surfaces of the pair of electrodes, and the organic molecules of the organic layer are oriented in the horizontal direction with respect to the facing surfaces of the pair of electrodes. Higher external quantum efficiency will be obtained.
  • the thickness of the perovskite film as described above is not particularly limited, but is preferably 1 to 2000 nm, more preferably 1 to 500 nm, and even more preferably 1 to 200 nm.
  • the thickness of the perovskite film can be measured with a stylus type film thickness meter.
  • the fact that a good perovskite structure is formed means that the target perovskite film, the organic layer formed only of the organic molecules of this perovskite film, and the inorganic layer formed only of the inorganic component of this perovskite film, respectively.
  • the absorption spectrum is measured, it can be confirmed by observing a sharp absorption peak that does not appear in other absorption spectra only in the perovskite membrane.
  • this sharp absorption peak is referred to as an “exciton absorption peak”.
  • the exciton absorption peak preferably has a half width of 10 to 30 nm.
  • the perovskite membrane can be formed by a perovskite-type compound.
  • the perovskite-type compound is an ionic compound composed of an organic cation, a divalent metal ion, and a halogen ion, and can form a perovskite-type crystal structure.
  • a two-dimensional perovskite-type compound capable of forming a structure in which an inorganic layer composed of octahedral inorganic skeletons arranged in two dimensions and an organic layer formed by oriented organic molecules are alternately arranged is used. Can be done.
  • Examples of this perovskite-type compound include compounds represented by the following general formulas (1a) to (3b).
  • A represents a monovalent organic cation
  • B represents a divalent metal ion
  • X represents a halogen ion.
  • the two A's and the four X's may be the same or different from each other.
  • the compound represented by the general formula (1a) has an inorganic layer in which the inorganic skeleton BX 4 corresponding to the octahedral portion of the perovskite-type structure is two-dimensionally arranged and an oriented monovalent organic cation A in two dimensions. It is possible to form a structure in which the organic layers are alternately arranged.
  • the inorganic skeleton BX 4 has a structure in which a divalent metal ion B is arranged at the center of an octahedron having a halogen ion X as an apex, and the apex is shared between adjacent octahedrons.
  • the monovalent organic cation A constitutes the "organic molecule" in the present invention, and a perovskite-type structure is formed by orienting the cationic group toward the inorganic layer side.
  • the monovalent organic cation represented by A in the general formula (1a) is preferably ammonium represented by the following general formula (4).
  • R represents a hydrogen atom or a substituent, and at least one of the four Rs is a substituent having two or more carbon atoms. Of the four Rs, the number of substituents having 2 or more carbon atoms is preferably 1 or 2, and more preferably 1. Further, it is preferable that one of the four Rs constituting ammonium is a substituent having two or more carbon atoms, and the rest are hydrogen atoms. When two or more of R are substituents, the plurality of substituents may be the same or different from each other.
  • the substituent having two or more carbon atoms and other substituents are not particularly limited, and examples thereof include an alkyl group, an aryl group, and a heteroaryl group, and these substituents are further an alkyl group, an aryl group, and the like. It may be substituted with a heteroaryl group, halogen or the like.
  • the carbon number of the substituent having 2 or more carbon atoms is preferably 2 to 30, more preferably 2 to 10, and even more preferably 2 to 5 for the alkyl group.
  • the aryl group is preferably 6 to 20, more preferably 6 to 18, and even more preferably 8 to 10.
  • the heteroaryl group is preferably 5 to 19, more preferably 5 to 17, and even more preferably 7 to 9.
  • hetero atom contained in the heteroaryl group examples include a nitrogen atom, an oxygen atom, a sulfur atom and the like.
  • the thickness of the organic layer is controlled according to the semimajor length of the substituent represented by R (for example, the chain length of the alkyl group), thereby controlling the characteristics of the functional layer composed of this compound. Can be done.
  • the monovalent organic cation represented by A preferably has at least one of an alkylene group and an aromatic ring, preferably has both an alkylene group and an aromatic ring, and has a structure in which the alkylene group and the aromatic ring are linked. It is more preferable to have ammonium, and it is further preferable to use ammonium represented by the following general formula (4a).
  • Ar 1 represents an aromatic ring.
  • n1 is an integer from 1 to 20.
  • the aromatic ring contained in the monovalent organic cation may be an aromatic hydrocarbon or an aromatic heterocycle, but is preferably an aromatic hydrocarbon.
  • hetero atom of the aromatic hetero ring examples include a nitrogen atom, an oxygen atom, a sulfur atom and the like.
  • the aromatic hydrocarbon is preferably a condensed polycyclic hydrocarbon having a structure in which a benzene ring and a plurality of benzene rings are condensed, and is preferably a benzene ring, a naphthalene ring, a phenanthrene ring, an anthracene ring, a chrysene ring, a tetracene ring, and the like.
  • the aromatic heterocycle is preferably a pyridine ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring, a pyrrol ring, a thiophene ring, a furan ring, a carbazole ring, or a triazine ring, preferably a pyridine ring, a pyrazine ring, a pyrimidine ring, or a pyridazine ring.
  • the aromatic ring of the monovalent organic cation may have a substituent such as an alkyl group, an aryl group, or a halogen atom (preferably a fluorine atom), or may be a substituent bonded to the aromatic ring or the aromatic ring.
  • the hydrogen atom present in may be a heavy hydrogen atom.
  • N1 in the general formula (4a) is an integer of 1 to 20, and is preferably an integer of 2 to 10.
  • A in addition to ammonium, formamidinium, cesium and the like can also be used.
  • Examples of the divalent metal ion represented by B include Cu 2+ , Ni 2+ , Mn 2+ , Fe 2+ , Co 2+ , Pd 2+ , Ge 2+ , Sn 2+ , Pb 2+ , Eu 2+ , and Sn. It is preferably 2+ and Pb 2+ , and more preferably Sn 2+ .
  • Examples of the halogen ion represented by X include fluorine, chlorine, bromine, and iodine ions. The halogen ions represented by the four Xs may all be the same, or may be a combination of two or three types of halogen ions.
  • all four Xs are the same halogen ion, and it is more preferable that all four Xs are chloride ions or bromine ions.
  • [CH 3 (CH 2 ) n2 NH 3 )] 2 SnI 4 (n2 2 to 17), (C 4 H 9 C 2 H 4 ), as preferable specific examples of the perovskite type compound represented by the general formula (1a).
  • a 4 of the general formula (1b) represents a divalent organic cation.
  • B and X in the general formula (1b) are synonymous with B and X in the general formula (1a), respectively.
  • the preferable ranges and specific examples of B and X of the general formula (1b) can be referred to, respectively.
  • the four Xs may be the same or different from each other.
  • the compound represented by the general formula (1b) has an inorganic layer in which the inorganic skeleton BX 4 corresponding to the octahedral portion of the perovskite-type structure is two-dimensionally arranged, and the oriented divalent organic cation A 4 in the two-dimensional arrangement. It is possible to form a structure in which the organic layers made of Here, the inorganic skeleton BX 4 has a structure in which a divalent metal ion B is arranged at the center of an octahedron having a halogen ion X as an apex, and the apex is shared between adjacent octahedrons.
  • the divalent organic cation A 4 constitutes the "organic molecule" in the present invention, and a perovskite-type structure is formed by orienting the cationic group toward the inorganic layer side.
  • the divalent organic cation represented by A 4 is preferably a compound represented by the following general formula (7).
  • Ar represents a substituted or unsubstituted arylene group.
  • the aromatic ring constituting the arylene group in Ar may be a monocyclic ring, a condensed ring in which two or more aromatic rings are condensed, or a linked ring in which two or more aromatic rings are linked. When two or more aromatic rings are connected, they may be linearly connected or may be branched.
  • the aromatic ring constituting the arylene group preferably has 6 to 22 carbon atoms, more preferably 6 to 18 carbon atoms, further preferably 6 to 14 carbon atoms, and even more preferably 6 to 10 carbon atoms. preferable.
  • Specific examples of the arylene group include a phenylene group, a naphthalene-diyl group, a biphenyl-diyl group, and a terphenyl-diyl group.
  • Examples of the substituent which may be substituted with an arylene group include an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a heteroaryl group having 3 to 40 carbon atoms, a stillben group, a terphenyl group, a thiophene group and the like. Can be mentioned. Further, the substituents substituted with the arylene group may be bonded to each other to form a cyclic structure together with the arylene group. Examples of the cyclic structure in which the substituents are bonded to each other to form together with the arylene group include an aromatic heterocycle formed by condensing an aromatic hydrocarbon ring and a heterocycle.
  • R 1 and R 2 each independently represent an alkylene group. A part of the methylene group constituting the alkylene group may be substituted with —O—.
  • the alkylene group in R 1 and R 2 may be linear, branched, or cyclic, but is preferably linear.
  • the alkylene group preferably has 1 to 20 carbon atoms, preferably 2 to 10, more preferably 3 to 8, and even more preferably 4 to 7.
  • M 1 and M 2 each independently represent a cationic group.
  • R 1 and R 2 may be the same or different from each other, but are preferably the same, and M 1 and M 2 may be the same or different from each other. However, it is preferable that they are the same as each other. Further, it is more preferable that R 1 and R 2 are the same as each other, and M 1 and M 2 are the same as each other. Further, the compound represented by the general formula (7) is preferably a compound represented by the general formula (8) described later and is a cationic group to which M 11 and M 12 are bonded with a nitrogen atom.
  • the divalent organic cation represented by A 4 is preferably a divalent organic cation having fluorescence emission property.
  • fluorescing due to the irradiation of the excitation light becomes excited singlet state S 1, when from the excited singlet state S 1 of deactivation to the underlying singlet state S 0, fluorescent Means that it can radiate.
  • a 2 in the general formula (2a) represents a monovalent organic cation having a larger carbon number than A 1 .
  • B and X of the general formula (2a) are synonymous with B and X of the general formula (1a), respectively, and A 2 of the general formula (2a) is synonymous with A of the general formula (1a).
  • the preferable ranges and specific examples of A 2 , B, and X of the general formula (2a) can be referred to, respectively.
  • the two A 2 and between the plurality of X each other may each be different be the same as each other.
  • a 1 and B may be the same or different from each other.
  • the monovalent organic cation represented by A 1 is a monovalent organic cation having a smaller carbon number than A 2 , and is preferably ammonium represented by the following general formula (5).
  • R 11 represents a hydrogen atom or a substituent, and at least one of the four R 11 is a substituent.
  • the number of the substituents of the four R 11 is preferably 1 or 2 in which, more preferably one. That is, the four R 11 constituting the ammonium, one of a substituent, is preferably the remainder are hydrogen atoms.
  • the plurality of substituents may be the same or different from each other.
  • the substituent is not particularly limited, and examples thereof include an alkyl group and an aryl group (phenyl group, naphthyl group, etc.), and these substituents may be further substituted with an alkyl group, an aryl group, or the like.
  • the number of carbon atoms of the substituent is preferably 1 to 30, more preferably 1 to 20, and even more preferably 1 to 10 for the alkyl group.
  • the aryl group is preferably 6 to 30, more preferably 6 to 20, and even more preferably 6 to 10.
  • As the monovalent organic cation represented by A 1 and A 2 formamidinium or the like can be used in addition to ammonium, and the organic cation may be replaced with cesium ion or the like.
  • the compound represented by the general formula (2a) has a structure in which an inorganic layer composed of an octahedral inorganic skeleton B n X 3n + 1 and an organic layer composed of a monovalent organic cation A 2 are alternately arranged.
  • the monovalent organic cation A 2 of the organic layer constitutes the "organic molecule" in the present invention.
  • n corresponds to the number of stacked octahedrons in each inorganic layer and is an integer of 1 to 100.
  • the monovalent organic cation A 1 is arranged between the octahedral layers.
  • n is an integer of 1 to 100, preferably an integer of 1 to 5.
  • the perovskite-type compounds that can be used in the present invention are not limitedly interpreted by these compounds.
  • a 5 in the general formula (2b) represents a divalent organic cation having a larger carbon number than A 1 .
  • B and X in the general formula (2b) are respectively B and X in the general formula (1a) synonymous, A 1 in the general formula (2b) has the same meaning as A 1 in formula (2a).
  • the preferable ranges and specific examples of B and X of the general formula (2b) can be referred to, respectively, and the preferable ranges and specific examples of A 1 of the general formula (2b) can be referred to.
  • the preferable range and specific example of A 1 of the general formula (2a) can be referred to.
  • the preferable range and specific example of A 5 of the general formula (2b) the preferable range and specific example of A 4 of the general formula (1b) can be referred to.
  • the plurality of Xs may be the same or different from each other.
  • a 1 and B may be the same or different from each other.
  • the compound represented by the general formula (2b) has a structure in which an inorganic layer composed of an octahedral inorganic skeleton B n X 3n + 1 and an organic layer composed of a divalent organic cation A 5 are alternately arranged.
  • the divalent organic cation A 5 of the organic layer constitutes the "organic molecule" in the present invention.
  • n corresponds to the number of stacked octahedrons in each inorganic layer and is an integer of 1 to 100.
  • the monovalent organic cation A 1 is arranged between the octahedral layers.
  • a 2 of the general formula (3a) represents a monovalent organic cation having a larger carbon number than A 1 .
  • B and X in the general formula (3a) are synonymous with B and X in the general formula (1a), respectively.
  • a 1 in the general formula (3a) has the same meaning as A 1 in formula (2a).
  • the preferred ranges and examples of A 1 in the general formula (3a) can refer to preferred ranges and examples of A 1 in the general formula (2a).
  • the two A 2 and between the plurality of X each other may each be different be the same as each other.
  • a 1 and B may be the same or different from each other.
  • the compound represented by the general formula (3a) forms a structure in which an inorganic layer composed of an inorganic skeleton Bm X 3m + 2 and an organic layer composed of a monovalent organic cation A 2 are alternately arranged.
  • the monovalent organic cation A 2 of the organic layer constitutes the "organic molecule" in the present invention.
  • m corresponds to the number of layers in each inorganic layer and is an integer of 1 to 100.
  • the monovalent organic cation represented by A 2 is a monovalent organic cation having a larger carbon number than A 1 , preferably ammonium represented by the above general formula (5), and the following general formula ( It is more preferably ammonium represented by 6).
  • R 12 and R 13 each independently represent a hydrogen atom or a substituent, each R 12 may be the same or different, and each R 13 is the same. May be different.
  • the substituent is not particularly limited, and examples thereof include an alkyl group, an aryl group, an amino group, a halogen atom and the like, and the alkyl group, the aryl group and the amino group referred to herein are further an alkyl group, an aryl group and an amino group. , Halogen atom or the like may be substituted.
  • the number of carbon atoms of the substituent is preferably 1 to 30, more preferably 1 to 20, and even more preferably 1 to 10 for the alkyl group.
  • the aryl group is preferably 6 to 30, more preferably 6 to 20, and even more preferably 6 to 10.
  • the thickness of the organic layer is controlled according to the semimajor length of the substituent represented by R 12 (for example, the chain length of the alkyl group), thereby controlling the properties of the functional layer composed of this mixture. be able to.
  • R 12 for example, the chain length of the alkyl group
  • R 13 for example, an amino group or a halogen atom can be selected as R 12 and a hydrogen atom or an alkyl group can be selected and combined as R 13 .
  • an amino group or a halogen atom can be selected as R 12 and a hydrogen atom can be selected and combined as R 13 .
  • the monovalent organic cation represented by A 2 form amidineium or the like can be used in addition to ammonium, and the organic cation may be replaced with cesium ion or the like.
  • a compound represented by the following general formula (3aa) can be mentioned.
  • [NH 2 C (I) NH 2 ] 2 (CH 3 NH 3 ) m Sn m I 3 m + 2 (3aa)
  • m is an integer of 2 to 100, preferably an integer of 2 to 5.
  • the perovskite-type compounds that can be used in the present invention are not limitedly interpreted by these compounds.
  • a 5 in the general formula (3b) represents a divalent organic cation having a larger carbon number than A 1 .
  • B and X in the general formula (3b) are synonymous with B and X in the general formula (1a), respectively.
  • a 1 in the general formula (3b) has the same meaning as A 1 in formula (2a).
  • the preferred ranges and examples of A 1 in the general formula (3b), can refer to preferred ranges and examples of A 1 in the general formula (2a).
  • the preferable range and specific example of A 5 of the general formula (3b) the preferable range and specific example of A 4 of the general formula (1b) can be referred to.
  • the plurality of Xs may be the same or different from each other.
  • a 1 and B may be the same or different from each other.
  • the compound represented by the general formula (3b) forms a structure in which an inorganic layer composed of an inorganic skeleton Bm X 3m + 2 and an organic layer composed of a divalent organic cation A 5 are alternately arranged.
  • the divalent organic cation A 5 of the organic layer constitutes the "organic molecule" in the present invention.
  • m corresponds to the number of layers in each inorganic layer and is an integer of 1 to 100.
  • the total number of inorganic layers and organic layers formed by the compounds represented by the general formulas (1a) to (3b) is preferably 1 to 100, more preferably 1 to 50, and 5 to 20. Is more preferable.
  • perovskite-type compounds listed above those containing at least one of Sn 2+ and Pb 2+ as divalent metal ions, compounds represented by the general formula (7) as organic cations, methylammonium, and formua Mijiniumu, those containing at least one cesium, Br as the halogen ions -, Cl -, I -, F - is intended to include at least one.
  • the compound represented by the general formula (1a) to (3b) is preferable, and BTAPbBr 4 is most preferable.
  • the structure of BTA the structure of a specific example of the compound represented by the general formula (7) can be referred to.
  • perovskite type compound may be used alone, or two or more types may be used in combination.
  • Preferred combinations include two or more combinations of CH 3 NH 3 SnI 3 and CH 3 NH 3 SnI q F 3-q (where q is an integer of 0 to 2).
  • the perovskite-type compound used for forming the perovskite film preferably has a carrier mobility of 10 2-1 to 10 3 cm 2 V -1 s -1 and 10 -1 to 10 2 cm 2 V -1 s -1. more preferably, even more preferably from 10 0 ⁇ 10 2 cm 2 V -1 s -1.
  • the carrier mobility of the perovskite-type compound can be measured by the following method.
  • a laminate was prepared in which a glass substrate, an anode made of indium tin oxide (ITO) having a thickness of 100 nm, and a film made of molybdenum oxide (MoO x ) having a thickness of 10 nm were laminated in this order, and this laminate was prepared.
  • a film of a perovskite type compound whose carrier mobility is to be measured is formed to a thickness of 1000 nm.
  • a film made of molybdenum oxide having a thickness of 10 nm and a cathode made of aluminum having a thickness of 100 nm are sequentially laminated on the film of this perovskite type compound to form a hole transport device.
  • a film made of cesium having a thickness of 0.5 nm is formed between the anode and the film made of the perovskite type compound and between the film made of the perobskite type compound and the cathode.
  • the electron transport device is manufactured in the same manner as in the process of manufacturing the hole transport device.
  • the current density-voltage characteristics were measured to obtain a double logarithmic graph, and the current density and applied voltage obtained from the graph were used, and the space charge limiting current formula below was used to obtain the perovskite film.
  • J is the current density
  • ⁇ r is the permittivity
  • ⁇ 0 is the permittivity of the vacuum
  • ⁇ is the carrier mobility
  • L is the film thickness
  • V is the applied voltage.
  • the carrier mobility ⁇ calculated using the current density and the applied voltage measured by the hole transport device is defined as the hole mobility ⁇ h, and the current density and the applied voltage measured by the electron transport device are used.
  • the calculated carry mobility ⁇ be the electron mobility ⁇ e .
  • the method for forming the perovskite film is not particularly limited, and may be a dry process such as a vacuum vapor deposition method or a wet process such as a solution coating method.
  • a dry process such as a vacuum vapor deposition method or a wet process such as a solution coating method.
  • the film can be formed in a short time with a simple device, so that there is an advantage that the cost can be suppressed and mass production is easy.
  • the vacuum vapor deposition method has an advantage that a film having a better surface condition can be formed.
  • a compound A 4 X 2 composed of a divalent organic cation and a halogen ion is different from a metal halide BX 2.
  • a co-deposited method of co-depositing from a vapor deposition source can be used.
  • a film containing a perovskite-type compound represented by another general formula can also be formed by applying this method to co-deposit a compound composed of an organic cation and a halogen ion and a metal halide. it can.
  • the compound A 4 X 2 composed of an organic cation and a halogen ion is reacted with the metal halide BX 2 in a solvent.
  • a perovskite-type compound is synthesized, and a coating liquid containing the perovskite-type compound is applied to the surface of the support and dried to form a film.
  • this method is applied to synthesize a perovskite-type compound in a solvent, and a coating solution containing this perovskite compound is applied to the surface of the support. It can be dried and formed.
  • the coating method of the coating liquid is not particularly limited, and conventionally known coating methods such as a gravure coating method, a bar coating method, a printing method, a spray method, a spin coating method, a dip method, and a die coating method can be used. It is preferable to use the spin coating method because a coating film having a relatively thin thickness can be uniformly formed.
  • the solvent of the coating liquid is not particularly limited as long as it can dissolve the perovskite type compound.
  • ethers methylformate, ethylformate, propylformate, pentylformate, methyl acetate, ethyl acetate, pentyl acetate, etc.
  • ketones ⁇ -butyrolactone, N-methyl-2-pyrrolidone, etc.
  • Acetone dimethyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, methylcyclohexanone, etc.
  • ethers diethyl ether, methyl-tert-butyl ether, diisopropyl ether, dimethoxymethane, dimethoxyethane, 1,4-dioxane, 1,3- Dioxolane, 4-methyldioxolane, tetrahydrofuran, methyl tetrahydrofuran, anisole,
  • esters, ketones, ethers and alcohols that is, -O-, -CO-, -COO-, -OH.
  • the hydrogen atom in the hydrocarbon moiety of esters, ketones, ethers and alcohols may be substituted with a halogen atom (particularly, a fluorine atom).
  • the content of the perovskite-type compound in the coating liquid is preferably 1 to 50% by mass, more preferably 2 to 30% by mass, and 5 to 20% by mass with respect to the total amount of the coating liquid. Is even more preferable. Further, it is preferable to apply a coating liquid to the surface of the support and then heat-treat the coating film.
  • the heat treatment temperature of the coating film is preferably 70 to 200 ° C.
  • the coating liquid applied to the surface of the support is preferably dried by natural drying or heat drying in an atmosphere substituted with an inert gas such as nitrogen. Further, the above heat treatment may also serve as drying of the coating liquid.
  • the organic electroluminescent device of the present invention has a pair of electrodes and a perovskite film formed between the pair of electrodes.
  • the perovskite film in the present invention efficiently emits light from organic molecules, and the light can be efficiently taken out to the light extraction side, so that the perovskite film can be effectively used as a light emitting layer of an organic electroluminescence element.
  • the organic electroluminescence device of the present invention may be composed of only a pair of electrodes and a perovskite film, or may have other layers.
  • one or more organic layers may be arranged between the electrodes in addition to the light emitting layer.
  • organic layers include a hole transport layer, a hole injection layer, an electron blocking layer, a hole blocking layer, an electron injection layer, an electron transport layer, an exciton blocking layer, and the like.
  • the hole transport layer may be a hole injection transport layer having a hole injection function
  • the electron transport layer may be an electron injection transport layer having an electron injection function.
  • 3 1 is a substrate
  • 2 is an anode
  • 3 is a hole injection layer
  • 4 is a hole transport layer
  • 5 is a light emitting layer
  • 6 is an electron transport layer
  • 7 is a cathode.
  • the anode and the cathode constitute the "pair of electrodes" in the present invention.
  • each member and each layer of the organic electroluminescence device will be described.
  • the organic electroluminescence device of the present invention is preferably supported by a substrate.
  • the substrate is not particularly limited as long as it is conventionally used for organic electroluminescence devices, and for example, a substrate made of glass, transparent plastic, quartz, silicon, or the like can be used.
  • anode As the anode in the organic electroluminescence element, a metal having a large work function (4 eV or more), an alloy, an electrically conductive compound, or a mixture thereof as an electrode material is preferably used.
  • electrode materials include metals such as Au and conductive transparent materials such as CuI, indium tin oxide (ITO), SnO 2 , and ZnO.
  • a material such as IDIXO (In 2 O 3- ZnO) which is amorphous and can produce a transparent conductive film may be used.
  • a thin film may be formed by forming a thin film of these electrode materials by a method such as thin film deposition or sputtering, and a pattern having a desired shape may be formed by a photolithography method, or when pattern accuracy is not required so much (about 100 ⁇ m or more). ), A pattern may be formed through a mask having a desired shape during vapor deposition or sputtering of the electrode material.
  • a coatable material such as an organic conductive compound
  • a wet film forming method such as a printing method or a coating method can also be used.
  • the transmittance is larger than 10%, and the sheet resistance as the anode is preferably several hundred ⁇ / ⁇ or less.
  • the film thickness depends on the material, but is usually selected in the range of 10 to 1000 nm, preferably 10 to 200 nm.
  • cathode a metal having a small work function (4 eV or less) (referred to as an electron-injectable metal), an alloy, an electrically conductive compound, or a mixture thereof is used as an electrode material.
  • electrode materials include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al 2 O). 3 ) Examples include mixtures, indium, lithium / aluminum mixtures, rare earth metals and the like.
  • a mixture of an electron injectable metal and a second metal which is a stable metal having a larger work function value than this for example, a magnesium / silver mixture.
  • a magnesium / silver mixture Magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al 2 O 3 ) mixture, lithium / aluminum mixture, aluminum and the like are suitable.
  • the cathode can be produced by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering.
  • the sheet resistance of the cathode is preferably several hundred ⁇ / ⁇ or less, and the film thickness is usually selected in the range of 10 nm to 5 ⁇ m, preferably 50 to 200 nm. Since the emitted light is transmitted, it is convenient that the emission brightness is improved if either the anode or the cathode of the organic electroluminescence element is transparent or translucent. Further, by using the conductive transparent material mentioned in the description of the anode for the cathode, a transparent or translucent cathode can be produced, and by applying this, an element in which both the anode and the cathode have transparency can be obtained. Can be made.
  • the light emitting layer is a layer that emits light after an excited state is generated by recombination of holes and electrons injected from each of the anode and the cathode, and can be composed of a perovskite film.
  • the perovskite membrane the description in the "Perovskite membrane” column can be referred to.
  • the perovskite film As described above, by using the perovskite film as the light emitting layer, high luminous efficiency and high light extraction efficiency can be realized.
  • the injection layer is a layer provided between the electrode and the organic layer to reduce the driving voltage and improve the emission brightness.
  • the injection layer can be provided as needed.
  • the blocking layer is a layer capable of blocking the diffusion of charges (electrons or holes) and / or excitons existing in the light emitting layer to the outside of the light emitting layer.
  • the electron blocking layer can be arranged between the light emitting layer and the hole transporting layer to prevent electrons from passing through the light emitting layer toward the hole transporting layer.
  • the hole blocking layer can be placed between the light emitting layer and the electron transporting layer to prevent holes from passing through the light emitting layer towards the electron transporting layer.
  • the blocking layer can also be used to prevent excitons from diffusing outside the light emitting layer. That is, the electron blocking layer and the hole blocking layer can each have a function as an exciton blocking layer.
  • the electron blocking layer or exciton blocking layer referred to in the present specification is used in the sense that one layer includes a layer having the functions of an electron blocking layer and an exciton blocking layer.
  • the hole blocking layer has a function of an electron transporting layer in a broad sense.
  • the hole blocking layer has a role of blocking the holes from reaching the electron transporting layer while transporting electrons, which can improve the recombination probability of electrons and holes in the light emitting layer.
  • As the material of the hole blocking layer a material of the electron transport layer described later can be used as needed.
  • the electron blocking layer has a function of transporting holes in a broad sense.
  • the electron blocking layer has a role of blocking electrons from reaching the hole transporting layer while transporting holes, which can improve the probability that electrons and holes are recombined in the light emitting layer. ..
  • the exciton blocking layer is a layer for blocking excitons generated by the recombination of holes and electrons in the light emitting layer from diffusing into the charge transport layer, and the excitons are inserted by inserting this layer. It is possible to efficiently confine it in the light emitting layer, and it is possible to improve the light emitting efficiency of the element.
  • the exciton blocking layer can be inserted into either the anode side or the cathode side adjacent to the light emitting layer, and both can be inserted at the same time.
  • the layer when the exciton blocking layer is provided on the anode side, the layer can be inserted between the hole transport layer and the light emitting layer adjacent to the light emitting layer, and when inserted on the cathode side, the light emitting layer and the cathode are inserted.
  • the layer can be inserted adjacent to the light emitting layer between and.
  • a hole injection layer, an electron blocking layer, or the like can be provided between the anode and the exciton blocking layer adjacent to the anode side of the light emitting layer, and the cathode and the excitation adjacent to the cathode side of the light emitting layer can be provided.
  • An electron injection layer, an electron transport layer, a hole blocking layer, and the like can be provided between the child blocking layer and the electron blocking layer.
  • the blocking layer it is preferable that at least one of the excited singlet energy and the excited triplet energy of the material used as the blocking layer is higher than the excited singlet energy and the excited triplet energy of the light emitting material.
  • the hole transport layer is made of a hole transport material having a function of transporting holes, and the hole transport layer may be provided with a single layer or a plurality of layers.
  • the hole transporting material has either injection or transport of holes or an electron barrier property, and may be either an organic substance or an inorganic substance.
  • Known hole transporting materials that can be used include, for example, triazole derivatives, oxadiazole derivatives, imidazole derivatives, carbazole derivatives, indolocarbazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, etc.
  • Amino-substituted chalcone derivatives oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilben derivatives, silazane derivatives, aniline copolymers, conductive polymer oligomers, especially thiophene oligomers, etc. It is preferable to use a group tertiary amine compound and a styrylamine compound, and it is more preferable to use an aromatic tertiary amine compound.
  • the electron transport layer is made of a material having a function of transporting electrons, and the electron transport layer may be provided with a single layer or a plurality of layers.
  • the electron transporting material (which may also serve as a hole blocking material) may have a function of transmitting electrons injected from the cathode to the light emitting layer.
  • Examples of the electron transporting layer that can be used include nitro-substituted fluorene derivatives, diphenylquinone derivatives, thiopyrandioxide derivatives, carbodiimides, freolenidenemethane derivatives, anthracinodimethane and anthrone derivatives, and oxadiazole derivatives.
  • a thiadiazole derivative in which the oxygen atom of the oxadiazole ring is replaced with a sulfur atom, and a quinoxalin derivative having a quinoxalin ring known as an electron-withdrawing group can also be used as an electron transport material.
  • a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used.
  • a perovskite film may be used for a layer other than the light emitting layer.
  • a perovskite film can also be used for the hole transport layer and the electron transport layer described above.
  • the perovskite film used for the light emitting layer and the perovskite film used for the layer other than the light emitting layer may be the same or different.
  • each organic layer constituting the organic electroluminescence device is sequentially formed on a substrate.
  • the film forming method of these layers is not particularly limited, and may be formed by either a dry process or a wet process.
  • the contents of the above-mentioned [Method of forming a film] can be referred to.
  • preferable materials that can be used for the organic electroluminescence device will be specifically exemplified.
  • the materials that can be used in the present invention are not limitedly interpreted by the following exemplary compounds. Further, even a compound exemplified as a material having a specific function can be diverted as a material having another function. First, examples of preferable compounds that can be used as a hole injection material will be given.
  • preferable compounds as materials that can be further added are given.
  • it may be added as a stabilizing material.
  • the organic electroluminescence device produced by the above method emits light by applying an electric field between the anode and the cathode of the obtained device. At this time, if the light is emitted by the excitation singlet energy, the light having a wavelength corresponding to the energy level is confirmed as the fluorescence emission and the delayed fluorescence emission. Further, in the case of light emission by excited triplet energy, the wavelength corresponding to the energy level is confirmed as phosphorescent light. Since normal fluorescence has a shorter fluorescence lifetime than delayed fluorescence emission, the emission lifetime can be distinguished by fluorescence and delayed fluorescence.
  • the excited triplet energy in a normal organic compound such as the compound of the present invention, is unstable and is converted into heat or the like, and the lifetime is short and the compound is immediately deactivated.
  • the excited triplet energy of a normal organic compound it can be measured by observing the light emission under the condition of extremely low temperature.
  • the organic electroluminescence device of the present invention can be applied to any of a single device, a device having a structure arranged in an array, and a structure in which an anode and a cathode are arranged in an XY matrix.
  • the hole transport layer and the electron transport layer are composed of a perovskite film having a thickness of 50 nm or more, the drive voltage is low, the power efficiency is high, and short circuits and current leaks between electrodes are obtained. Can be avoided.
  • the organic light emitting device such as the organic electroluminescence device of the present invention can be further applied to various applications. For example, it is possible to manufacture an organic electroluminescence display device using the organic electroluminescence device of the present invention.
  • organic electroluminescence device of the present invention can also be applied to organic electroluminescence lighting and backlight, which are in great demand.
  • the compound represented by the following general formula (8) is a novel compound.
  • the compound represented by the general formula (8) includes the organic cation of the above-mentioned perovskite membrane, a material for forming the organic cation (halide of the organic cation), a precursor for synthesizing the halide of the organic cation, and the like. Useful as an intermediate.
  • R 11 and R 12 each independently represent an alkylene group. A part of the methylene group constituting the alkylene group may be substituted with —O—.
  • the preferred range as described in the alkylene group can be referred to the description and the preferred range for the alkylene group for R 1 or the like of the general formula (7).
  • the alkylene group in R 11 and R 12 is preferably an alkyleneoxy group, that is, an alkylene group bonded to a benzene ring with an oxygen atom.
  • M 11 represents a group that binds to R 11 with a nitrogen atom
  • M 12 represents a group that binds to R 12 with a nitrogen atom.
  • the group bonded at the nitrogen atom in M 11 and M 12 may be a nonionic group or a cationic group.
  • the cationic group may form a salt with an anion. Examples of the nonionic group bonded with a nitrogen atom include a group represented by the following general formula (8a).
  • R 31 and R 32 each independently represent a hydrogen atom or a substituent.
  • R 31 and R 32 may be the same or different from each other, but are preferably the same.
  • the substituents in R 31 and R 32 include substituents capable of protecting an amino group, and the substituents may be bonded to each other to form a cyclic structure containing a nitrogen atom.
  • Examples of the cyclic structure formed by bonding substituents to each other include an indoline ring, an isoindoline ring, an isoindoline-1,3-dione ring, and the like.
  • Both R 31 and R 32 are preferably hydrogen atoms, and it is also preferable that the substituents are bonded to each other to form an isoindoline-1,3-dione ring. * Represents the bonding position to R 11 or R 12 of the general formula (8).
  • R 41 to R 43 each independently represent a hydrogen atom or a substituent.
  • R 41 to R 43 may be the same or different from each other, but are preferably the same.
  • Examples of the substituent in R 41 to R 43 include a substituent capable of protecting an amino group. It is preferable that all of R 41 to R 43 are hydrogen atoms.
  • X 41 represents a halogen ion.
  • the preferable range and specific example of the halogen ion the preferable range and specific example of X in the general formula (1a) can be referred to.
  • X 41 is preferably a bromine ion. * Is synonymous with * in the general formula (8a).
  • Examples of the cationic group bonded with a nitrogen atom include a group in which the halogen ion X 41 is removed from the group represented by the above general formula (8b).
  • R 41 to R 43 a preferable range, and a specific example, the corresponding description of the general formula (8b) can be referred to.
  • R 13 to R 22 each independently represent a hydrogen atom or a substituent.
  • R 13 to R 22 may be the same as or different from each other.
  • the substituents in R 13 to R 22 preferably have 1 to 8 atoms, and more preferably 1 to 4 atoms.
  • Preferred examples of the substituent include, for example, a lower alkyl group having 1 to 3 carbon atoms, and specific examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group and the like. It is also preferable that all of R 13 to R 22 are hydrogen atoms.
  • R 11 and R 12 may be the same or different from each other, but are preferably the same, and M 11 and M 12 may be the same or different from each other. However, it is preferable that they are the same as each other. Further, it is more preferable that R 11 and R 12 are the same as each other, and M 11 and M 12 are the same as each other.
  • specific examples of the compound represented by the general formula (8) will be illustrated. However, the compound represented by the general formula (8) that can be used in the present invention should not be construed as being limited by these specific examples.
  • compound 1c in which bromine ions are dissociated from compound 1 can also be mentioned as a specific example of the general formula (8).
  • compound 1 may be referred to as "BTABr 2 ".
  • compound 1 is useful as a material for forming a perovskite film
  • compound 2 is useful as an intermediate for synthesizing compound 1
  • compound 3 is a precursor for synthesizing compound 1. It is useful as.
  • the above compound 1c is useful as an organic cation constituting a perovskite membrane.
  • Ra1 represents an alkyl halide group in which at least one methylene group may be substituted with —O—.
  • Intermediate 3 and Intermediate a1' at least one of the methine groups constituting the cyclic structure may have its hydrogen atom substituted with a substituent.
  • the emission characteristics are evaluated by a fluorescence spectrophotometer (Horiba Seisakusho: FluoroMax-4), and the organic EL characteristics are evaluated by an external quantum efficiency measuring device (Hamamatsu Photonics: C9920-12) and an organic EL durability evaluation device (C9920-12).
  • a fluorescence spectrophotometer Horiba Seisakusho: FluoroMax-4
  • an external quantum efficiency measuring device Hamamatsu Photonics: C9920-12
  • an organic EL durability evaluation device C9920-12.
  • EAS-26B organic EL durability evaluation device
  • Example 1 Preparation and evaluation of an organic photoluminescence element having a perovskite film of BTAPbBr 4
  • Compound 1 (BTABr 2 ) and lead (II) bromide (PbBr 2 ) were dissolved in dimethyl sulfoxide at a molar ratio of 1: 1.
  • the reaction was carried out by stirring to obtain a solution of BTAPbBr 4 .
  • the content of BTAPbBr 4 in the solution was set to 150 mg / mL.
  • This solution was supplied onto a quartz substrate and spin-coated at 3000 rpm for 30 seconds to form a coating film.
  • the substrate on which this coating film is formed is heated on a hot plate at 70 ° C. for 15 minutes, and then at 100 ° C. for 5 minutes to form a perovskite film composed of BTAPbBr 4 with a thickness of 30 nm. It was a photoluminescence element.
  • the BTAPbBr 4 perovskite film was observed sharp absorption peak around 400 nm. Moreover, since this absorption peak was not observed in other membranes, it was found that it was derived from exciton absorption in the inorganic layer of the perovskite membrane. Further, as shown in the excitation spectrum of FIG. 5, the BTAPbBr 4 perovskite film was observed a peak derived from exciton. That is, it was found that this result was a result of the energy of the excitons formed in the inorganic layer being transferred to the BTA skeleton and causing the BTA skeleton to emit light.
  • emission peak derived from emission peak derived from exciton emission (the exciton emission peak) to BTA backbone was observed. Since the emission peak derived from the BTA skeleton is much larger than the exciton emission peak, it was found that the energy of the excitons formed in the inorganic layer is transferred to the BTA skeleton. Further, when the transient attenuation curves of light emission were measured at a wavelength of 520 nm for the BTAPbBr 4 perovskite film and the BTABr 2 film, respectively, it was found that the BTAPbBr 4 perovskite film had a slower emission attenuation than the BTABr 2 film. ..
  • Example 1 Fabrication and evaluation of an organic electroluminescence device having a perovskite film of BTAPbBr 4
  • An aqueous solution of PEDOT was supplied onto the ITO, spin-coated at 4000 rpm for 45 seconds, and then heated on a hot plate at 160 ° C. for 10 minutes to form a PEDOT layer having a thickness of 30 nm.
  • a chlorobenzene solution of PolyTPD was supplied onto the PEDOT layer, spin-coated at 1500 rpm for 60 seconds, and then heated on a hot plate at 120 ° C.
  • each film was formed on the perovskite film by a vacuum vapor deposition method.
  • T2T was vapor-deposited to a thickness of 20 nm to form a T2T layer
  • BPyTP2 was vapor-deposited to a thickness of 60 nm to form a BPyTP2 layer.
  • LiF was formed to a thickness of 0.5 nm
  • Al was formed to a thickness of 100 nm on the LiF to form a cathode, which was used as an organic electroluminescence device (EL element 1).
  • the layer structure of the produced organic electroluminescence device is shown in Table 1 below.
  • An X-ray structural analysis of the perovskite film formed here revealed that the inorganic layers and the organic layers were alternately arranged, the inorganic layers were formed in the direction perpendicular to the surface of the substrate, and the organic molecules were formed on the surface of the substrate. It was confirmed that it was oriented in the horizontal direction.
  • the upper VB of the valence band of the inorganic layer was ⁇ 5.89 eV
  • the lower end CB of the conduction band was -2.64 eV
  • the band gap Eg (I) was 3.25 eV.
  • the energy level of HOMO in the organic layer was ⁇ 6.14 eV
  • the energy level of LUMO was -2.20 eV
  • the energy gap Eg (O) between HOMO and LUMO was 3.94 eV.
  • the lowest excited singlet energy level E S1 organic layer (O) was 2.64 eV.
  • the external quantum efficiency of the produced EL element 1 was 10.0% on average, and high luminous efficiency could be achieved.
  • organic electroluminescence was produced in the same manner as in Example 1 except that an optical out-coupling sheet (manufactured by KIMOTO: OptSaver STE3) was applied to the surface of the glass substrate opposite to the anode to improve the external quantum efficiency. As a result of measurement, a higher luminous efficiency of 13.9% was obtained on average.
  • Example 2 Examples of other production of an organic electroluminescence device having a perovskite film of BTAPbBr 4
  • An organic electroluminescence device was produced in the same manner as in Example 1 except that the layer structure shown in Table 1 was adopted.
  • the method for forming each layer is the same as the method for forming the corresponding layer formed in Example 1.
  • the PVK layer of Example 3 was formed by a spin coating method, and the TPBi layer of Example 5 was formed by a vacuum vapor deposition method.
  • "/" in the element configuration column represents the boundary of each layer, and the numerical value in parentheses indicates the film thickness of each layer in units of "nm".
  • Example 1 Fabrication of Organic Electroluminescent Device Having BTC6 Film Instead of forming a perovskite film, the same as in Example 1 except that the following BTC6 was formed to a thickness of 30 nm by a vacuum vapor deposition method. An organic electroluminescence device was manufactured.
  • FIG. 7 shows the presumed orientation state of organic molecules in the BTC6 layer.
  • 101 represents an anode
  • 102 represents a BTC6 layer
  • 102a represents an organic molecule constituting the BTC6 layer.
  • the external quantum efficiency of the organic electroluminescence device produced in Comparative Example 1 was 1.8%. The reason why the external quantum efficiency is low is that the organic molecules are vertically oriented and there is no enhancing effect due to energy transfer from the inorganic layer.
  • FIG. 8 shows an alignment state of forming direction and organic molecules of the inorganic layer to be estimated in PEAPbBr 4 perovskite film.
  • 201 denotes an anode
  • 202 PEAPbBr 4 perovskite film
  • 203 an inorganic layer
  • 204 is organic layer
  • 204a is the organic molecules constituting the organic layer.
  • the inorganic layer is formed in the horizontal direction with respect to the surface of the anode, the organic molecules were oriented perpendicularly to the surface of the anode ..
  • the present invention it is possible to provide an organic electroluminescence device having high efficiency such as luminous efficiency. Further, since the perovskite film is used for the light emitting layer or the like, the manufacturing cost of the organic electroluminescence element can be reduced. Therefore, the present invention has high industrial applicability.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Electroluminescent Light Sources (AREA)

Abstract

La présente invention concerne un élément électroluminescent organique qui comprend une paire d'électrodes et une couche pérovskite formée entre la paire d'électrodes, la couche pérovskite ayant une structure dans laquelle une couche inorganique et une couche organique contenant des molécules organiques sont disposées de manière alternée, la couche inorganique et la couche organique satisfont Eg(O) > Eg(I) > ES1(O). Eg(O) représente la largeur de la bande interdite entre le niveau HOMO et le niveau LUMO dans la couche organique, Eg(I) représente la largeur de la bande interdite entre la bande de valence et la bande de conduction dans la couche inorganique, et ES1(O) représente le niveau d'énergie singulet excité minimal de la couche organique.
PCT/JP2020/010890 2019-03-15 2020-03-12 Élément électroluminescent organique et composé WO2020189519A1 (fr)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2022209956A1 (fr) * 2021-03-31 2022-10-06 出光興産株式会社 Élément électroluminescent organique, procédé de production d'élément électroluminescent organique, membrane, structure multicouche, film, composition et dispositif électronique
JP2023530077A (ja) * 2021-04-13 2023-07-13 浙江大学 光電デバイス及びその製造方法

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Publication number Priority date Publication date Assignee Title
JP2018107129A (ja) * 2016-12-23 2018-07-05 株式会社半導体エネルギー研究所 発光素子、発光装置、電子機器、表示装置及び照明装置
CN109369569A (zh) * 2018-11-01 2019-02-22 华东师范大学 一类检测丙酮醛的荧光探针及其制备方法和应用
CN109369684A (zh) * 2018-11-01 2019-02-22 华东师范大学 一类电子供体-受体-供体荧光分子及其制备方法和应用

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2018107129A (ja) * 2016-12-23 2018-07-05 株式会社半導体エネルギー研究所 発光素子、発光装置、電子機器、表示装置及び照明装置
CN109369569A (zh) * 2018-11-01 2019-02-22 华东师范大学 一类检测丙酮醛的荧光探针及其制备方法和应用
CN109369684A (zh) * 2018-11-01 2019-02-22 华东师范大学 一类电子供体-受体-供体荧光分子及其制备方法和应用

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2022209956A1 (fr) * 2021-03-31 2022-10-06 出光興産株式会社 Élément électroluminescent organique, procédé de production d'élément électroluminescent organique, membrane, structure multicouche, film, composition et dispositif électronique
JP2023530077A (ja) * 2021-04-13 2023-07-13 浙江大学 光電デバイス及びその製造方法

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