Organic electroluminescent element and method for generating green light using an organic electroluminescent element

Abstract

The present invention relates to an organic electroluminescent device comprising an emitting layer B comprising a host material, a phosphorescent material and an emitter material, which exhibits a narrow (represented by a small full width at half maximum (FWHM)) green emission at an emission maximum between 500 and 560 nm. The present invention also relates to a method for generating green light by the organic electroluminescent device according to the present invention.

Description

[Technical Field]

[0001] The present invention relates to an organic electroluminescent element comprising a light-emitting layer B including a host material, a phosphorescent material, and an emitter material, wherein the organic electroluminescent element exhibits narrow (represented by a small full width at half maximum (FWHM)) green light emission at maximum emission in the range of 500 to 560 nm. The present invention also relates to a method for generating green light using the organic electroluminescent element according to the present invention. [Background technology]

[0002] For example, organic electroluminescent devices, such as organic light-emitting diodes (OLEDs), light-emitting electrochemical cells (LECs), and light-emitting transistors, which include one or more light-emitting layers based on organic materials, are becoming increasingly important. OLEDs, in particular, are promising components for electronic products such as screens, displays, and lighting devices. In contrast to most electroluminescent devices that are substantially based on inorganic materials, organic electroluminescent devices based on organic materials can usually be produced in a flexible and particularly thin layer. OLED-based screens and displays already available today have excellent efficiency and long lifespan, or excellent color purity and long lifespan, but they do not possess all three characteristics.

[0003] The color purity or color point of an OLED is generally provided by CIEx and CIEy coordinates, while the color gamut for next-generation displays is provided by so-called BT-2020 and DCPI3 values. Generally, obtaining such color coordinates requires modifying the cavity and adjusting the color coordinates. To achieve high efficiency in the upper light-emitting element while targeting such a color gamut, a narrow emission spectrum is required in the lower light-emitting element.

[0004] While the latest phosphorescent emitters exhibit relatively broad emission, this is reflected in the broad emission of phosphorescent-based OLEDs (PHOLEDs) with emission spectra having a full width at half maximum (FWHM) greater than 0.25 eV. The broad emission spectrum of PHOLEDs in the lower light-emitting element targets the BT-2020 and DCPI three-color regions, resulting in high outcoupling efficiency losses for the upper light-emitting element structure. [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] In recent years, some fluorescent emitters or thermally-activated delayed fluorescence (TADF) emitters have been developed that exhibit a somewhat narrower emission spectrum, representing FWHM with emission spectra below 0.25 eV, making them even more suitable for achieving the BT-2020 and DCPI three-color regions. However, such fluorescent and TADF emitters generally exhibit low efficiency not only due to low lifetimes caused by exciton-polaron or exciton-exciton extinction, but also due to decreased efficiency at higher brightness levels (i.e., OLED roll-off behavior). [Means for solving the problem]

[0006] Surprisingly, the light-emitting layer of the organic electroluminescent device, including the host material, phosphorescent material, and emitter material, exhibits the emission of green light with a small full width at half maximum (FWHM). It was revealed that the organic electroluminescent device possesses excellent lifetime and quantum efficiency, and emits green light. Here, the primary emission of the organic electroluminescent device originates from the small FWHM emitter material. [Effects of the Invention]

[0007] Such an organic electroluminescent device produces green light emission with a small FWHM and CIEx and CIEy color coordinates close to the specifications defined by DCPI3 and BT2020. MODE FOR CARRYING OUT THE INVENTION

[0008] Accordingly, according to one aspect of the present invention, there is provided an organic electroluminescent device comprising a light-emitting layer B, wherein (i) a lowest excited singlet state energy level S₁ P and a lowest excited triplet state energy level T₁ P , having energy E HOMO (H P ), a highest occupied molecular orbital HOMO(H P ), and energy E LUMO (H P ), a lowest unoccupied molecular orbital LUMO(H P ), and a host material H P ; (ii) a lowest excited singlet state energy level S₁ E and a lowest excited triplet state energy level T₁ E , having energy E HOMO ( E B ), a highest occupied molecular orbital HOMO( E B ), and energy E LUMO ( E B ), a lowest unoccupied molecular orbital LUMO(E E ), and a phosphorescent material E B ; and (iii) a lowest excited singlet state energy level S₁ S and a lowest excited triplet state energy level T₁ S , having energy E HOMO ( S B ), a highest occupied molecular orbital HOMO( S B ), and energy E LUMO ( S B ), a lowest unoccupied molecular orbital LUMO( S BA small FWHM emitter S) B and, The phosphorescent material E B The energy is transmitted to the small half-width emitter S B This is transmitted to the small half-width emitter S B It emits light with a maximum emission in the 500nm to 560nm range. An organic electroluminescent element is provided to which the relationship expressed by the following equations (1) to (4) is applied: T1 E >S1 S Formula (1) T1 P >T1 S Formula (2) T1 P >T1 E Formula (3) T1 P >S1 E Equation (4).

[0009] According to one embodiment, phosphorescent material E B The lowest excited triplet state energy is obtained with a small FWHM emitter S B It is higher than the lowest excited singlet state energy of the host material H. P The lowest excited triplet state energy is obtained with a small FWHM emitter S B It is higher than the lowest excited triplet state energy of the host material H. P The lowest excited triplet state energy of phosphorescent material E B It can also be higher than the lowest excited triplet state energy of the host material H. P The lowest excited triplet state energy of phosphorescent material E B This can also be higher than the lowest excited singlet state energy. In one embodiment, a small FWHM emitter S B It can have an emission spectrum with a full width at half maximum (FWHM) of approximately 0.25 eV (i.e., ≤0.25 eV) or less.

[0010] In one embodiment, an emission spectrum having a full width at half maximum (FWHM) of approximately 0.25 eV or less is observable for a fluorescent emitter and a thermally activated delayed fluorescent emitter. In one embodiment, an emission spectrum having a full width at half maximum (FWHM) of approximately 0.25 eV or less is not observable for a phosphorescent emitter. In one embodiment, the small FWHM emitter S B is phosphorescent material E B It is possible to have an emission spectrum that has a half-width (FWHM) smaller than the FWHM of the emission spectrum: FWHM(S B ) <FWHM(E B ).

[0011] In one embodiment, the organic electroluminescent element has a maximum emission wavelength of λ from 500 nm to 560 nm. max (D) can be represented.

[0012] In one embodiment, the organic electroluminescent element has a maximum emission wavelength of λ from 510 nm to 550 nm. max (D) can be represented.

[0013] In one embodiment, a small FWHM emitter S B It can emit light with a maximum emission in the 510nm to 550nm range.

[0014] In one embodiment, the light-emitting layer B of the organic electroluminescent element is at the lowest excited singlet state energy level S1 N , the lowest excited triplet state energy level T1 N Energy E HOMO (H N ) has the highest occupied orbit HOMO(H N ), and energy E LUMO (H N ) has the lowest airspace LUMO(H N ) Host material H N It may further include, The relationships expressed by the following equations (2N), (3N), and (4N) apply. T1 N >T1 SFormula (2N) T1 N >T1 E Formula (3N) T1 N >S1 E Formula (4N) A relationship represented by the following formulas (5) to (11) applies: E LUMO (H P )>E LUMO ( E S ) Formula (5) E LUMO (H P )>E LUMO (E B ) Formula (6) E HOMO (H P )<E HOMO ( E S ) Formula (7) E HOMO (H P )<E HOMO (E B ) Formula (8) E LUMO (H N )<E LUMO ( E S ) Formula (9) E LUMO (H N )<E LUMO (E B ) Formula (10) E HOMO (H N )<E HOMO ( E S ) Formula (11) E HOMO (H N )<E HOMO (E B ) Formula (12).

[0015] According to the present invention, the host material H N has a lowest excited triplet state energy that may be higher than the lowest excited triplet state energy of the narrow half-width emitter S B . The lowest excited triplet state energy of the host material H N may be higher than the lowest excited triplet state energy of the phosphorescent material EB It may be higher than the lowest excited triplet state energy of the host material H. N The lowest excited triplet state energy of phosphorescent material E B It may be higher than the lowest excited singlet state energy.

[0016] Also, host material H P The lowest unoccupied orbital (LUMO) energy is given by a small half-width emitter S B It may be higher than the lowest unsaturated orbital (LUMO) energy of the host material H. P The lowest unseen orbital (LUMO) energy is that of phosphorescent material E B It may be higher than the lowest unoccupied orbit (LUMO) energy.

[0017] Host material H P The highest occupied orbital (HOMO) energy is given by a small half-width emitter S B It may be lower than the highest occupied orbital (HOMO) energy of the host material H. P The highest occupied orbital (HOMO) energy is that of phosphorescent material E B It may be lower than the highest occupied orbital (HOMO) energy.

[0018] Also, host material H N The lowest unoccupied orbital (LUMO) energy is given by a small half-width emitter S B It may be lower than the lowest unsaturated orbital (LUMO) energy of the host material H. N The lowest unseen orbital (LUMO) energy is that of phosphorescent material E B It may be lower than the lowest unoccupied orbit (LUMO) energy.

[0019] Host material H N The highest occupied orbital (HOMO) energy is given by a small half-width emitter S B It may be lower than the highest occupied orbital (HOMO) energy of the host material H. N The highest occupied orbital (HOMO) energy is that of phosphorescent material E B It may be lower than the highest occupied orbital (HOMO) energy.

[0020] In one embodiment, the relationship represented by at least one of the following formulas (2E) and (3E), as well as the relationship represented by formula (1E), are applicable: E LUMO (H N )-E HOMO (H P )>T1 E Formula (1E) E LUMO (H P )-E LUMO (H N )≧0.2eV Formula (2E) E HOMO (H P )-E HOMO (H N )≧0.2eV Equation (3E).

[0021] Host material H N The lowest unseen orbital (LUMO) energy and the host material H P The difference from the highest occupied orbital (HOMO) energy is the phosphorescent material E B It may be greater than the lowest excited triplet state energy.

[0022] Host material H P The highest occupied orbital (HOMO) energy is given by the host material H N The HOMO energy may be at least 0.20 eV higher than that, i.e., E HOMO (H P ) is E HOMO (H N It may be negative by at least 0.20 eV.

[0023] H N LUMO and H P The energy difference between H and HOMO is H N HOMO and H P The energy difference with the HOMO is greater than (E LUMO (H N )-E HOMO (H P )>E HOMO (H P )E HOMO (H N )) In one embodiment, host material HP The HOMO energy is the host material H N The HOMO energy is 0.20 eV higher, preferably 0.25 eV higher, or more preferably 0.30 eV higher.

[0024] Typically, the host material H P The HOMO energy is the host material H N It is less than 4.0 eV, preferably less than 3.0 eV, more preferably less than 2.0 eV, or even less than 1.0 eV higher than the HOMO energy.

[0025] As an alternative, host material H P The lowest unseen orbital (LUMO) energy is given by the host material H N The LUMO energy may be at least 0.20 eV higher than that. That is, E LUMO (H P ) is E LUMO (H N ) may be negative by at least 0.20 eV. N LUMO and H P The energy difference between H and HOMO is H N LUMO and H P The energy difference with LUMO is greater than (E LUMO (H N )-E HOMO (H P )>E LUMO (H P )-E LUMO (H N )) In one embodiment, host material H P The LUMO energy is given by the host material H N The LUMO energy is approximately 0.20 eV higher, preferably 0.25 eV higher, or more preferably 0.30 eV higher than the LUMO energy. Typically, the host material H P The LUMO energy is given by the host material H N It is less than 4.0 eV, preferably less than 3.0 eV, more preferably less than 2.0 eV, or even less than 1.0 eV higher than the LUMO energy.

[0026] Surprisingly, the main contribution to the light emission band of the optoelectronic device according to the present invention is i)E B From S B Sufficient energy transfer to, and ii) host material H P and H N From E B and / or S B S represents sufficient energy transfer to B It became clear that this was caused by the release of [unclear substance].

[0027] In one embodiment, host material H P The highest occupied orbital (HOMO) energy is given by the host material H N The HOMO energy may be at least 0.20 eV higher than that of the host material H P The lowest unseen orbital (LUMO) energy is given by the host material H N The LUMO energy may be at least 0.20 eV higher than the LUMO energy.

[0028] In one embodiment, host material H P The HOMO energy is the host material H N The HOMO energy is 0.20 eV higher than that of the host material H, preferably 0.25 eV higher, or more preferably 0.30 eV higher. P The LUMO energy is given by the host material H N The LUMO energy is 0.20 eV higher, preferably 0.25 eV higher, or more preferably 0.30 eV higher.

[0029] In one embodiment, H P and H N H can form an exciplex. Those skilled in the art will know that H can form an exciplex. P and H N A method for selecting a pair of, and in addition to the aforementioned requirements for the HOMO energy level and / or LUMO energy level, H P and H N We know the selection criteria, such as low 3D shielding.

[0030] In one embodiment, H P The following compounds can be selected from the group consisting of the following compounds, or a mixture of two or more of the following compounds:

[0031] [ka]

[0032] [ka]

[0033] [ka]

[0034] [ka]

[0035] [ka]

[0036] In one embodiment, H N The following compounds can be selected from the group consisting of the following compounds, or a mixture of two or more of the following compounds:

[0037] [ka]

[0038] [ka]

[0039] In one embodiment, H P and H N H forms an exciplex; P and S BH does not form an exciplex; N and S B It does not form an exciplex, E B and S B It does not form an exciplex.

[0040] In one embodiment, H P and H N H forms an exciplex; P and E B H does not form an exciplex; N and E B H does not form an exciplex; P and S B H does not form an exciplex; N and S B It does not form an exciplex, E B and S B It does not form an exciplex.

[0041] H P and E B Exciplex formation; H N and E B Exciplex formation; H P and S B Exciplex formation; H N and S B Exciplex formation; or E B and S B Exciplex formation.

[0042] In one embodiment, H N It does not necessarily have to contain any phosphine oxide group, and in particular H N It is not bis[2-(diphenylphosphino)phenyl] ether oxide (DPEPO).

[0043] As used herein, the terms organic electroluminescent element and photoluminescent element refer to a host material H P Phosphorescent material E B and small FWHM emitter S BIt can be understood in the broadest sense as any element including a light-emitting layer B.

[0044] In its broadest sense, an organic electroluminescent element can be understood as any element based on an organic material suitable for emitting light in the visible light or near-ultraviolet (UV) range, i.e., in the wavelength range of 380 to 800 nm. Preferably, the organic electroluminescent element can emit light in the visible light range, i.e., 400 to 800 nm.

[0045] In one embodiment, the organic electroluminescent element may be an element selected from the group consisting of organic light-emitting diodes (OLEDs), light-emitting electrochemical cells (LECs), and light-emitting transistors.

[0046] Particularly preferably, the organic electroluminescent element may be an organic light-emitting diode (OLED). Selectively, the organic electroluminescent element may be entirely opaque, translucent, or (essentially) transparent.

[0047] In the context of this invention, the term "layer" preferably refers to a body having a wide planar shape.

[0048] The light-emitting layer B may preferably have a thickness of 1 mm or less, more preferably 0.1 mm or less, even more preferably 10 μm or less, even more preferably 1 μm or less, and particularly 0.1 μm or less.

[0049] In one embodiment, a small half-width (FWHM) emitter S B This may be an organic material. According to the present invention, an organic emitter or organic material can mean that the emitter or material is composed (mainly) of hydrogen (H), carbon (C), nitrogen (N), boron (B), silicon (Si), and selectively fluorine (F), selectively bromine (Br), and selectively oxygen (O). Particularly preferably, the organic emitter or organic material does not contain any transition metals.

[0050] In one embodiment, a small half-width (FWHM) emitter S B This may be an organic TADF material. In one embodiment, a small FWHM emitter S B This may be an organic emitter.

[0051] Compound H P , compound H N , emitter E B and emitter S B It is included in organic electroluminescent elements in any amount and any proportion.

[0052] In one embodiment, in the organic electroluminescent element of the present invention, the light-emitting layer B is based on the weight of the emitter E B Compound H P It may contain even more of it.

[0053] In one embodiment, in the organic electroluminescent element of the present invention, the light-emitting layer B is based on the weight of the emitter E B Compound H N It may contain even more of it.

[0054] In one embodiment, in the organic electroluminescent element of the present invention, the light-emitting layer B is based on the weight of the emitter S B TADF material E B It may contain even more of it.

[0055] H N In one selective embodiment, in the organic electroluminescent element of the present invention, the light-emitting layer B is (i) 10-84% by weight of host compound H P and, (ii) 0-84% by weight of host compound H N and, (iii) 5-15% by weight of phosphorescent material E B and, (iv) Small FWHM emitter S of 1-10% by weight B And selectively (v) may consist of one or more solvents in an amount of 0 to 72% by weight (or may consist of (i), (ii), (iii), (iv) and selectively (v)).

[0056] H N In one selective embodiment, in the organic electroluminescent element of the present invention, the light-emitting layer B is (i) 22-70% by weight of host compound H P and, (ii) 0-70% by weight of host compound H N and, (iii) 5-10% by weight of phosphorescent material E B and, (iv) 1-5% by weight of emitter S B And selectively (v) may consist of one or more solvents in an amount of 0 to 72% by weight (or may consist of (i), (ii), (iii), (iv) and selectively (v)).

[0057] H N In one embodiment in which such an embodiment exists, the light-emitting layer B in the organic electroluminescent element of the present invention is (i) 10-30% by weight of host compound H P and, (ii) 40-74% by weight of host compound H N and, (iii) 15-30% by weight of phosphorescent material E B and, (iv) Small FWHM emitter S of 1-5% by weight B And selectively (v) may consist of one or more solvents in an amount of 0-34% by weight (or (i), (ii), (iii), (iv) and selectively (v)).

[0058] H N In one embodiment in which such an embodiment exists, the light-emitting layer B in the organic electroluminescent element of the present invention is (i) 40-74% by weight of host compound H N and, (ii) 10-30% by weight of host compound HP and, (iii) 15-30% by weight of phosphorescent material E B and, (iv) Small FWHM emitter S of 1-5% by weight B And selectively (v) may consist of one or more solvents in an amount of 0-34% by weight (or (i), (ii), (iii), (iv) and selectively (v)).

[0059] In one embodiment, phosphorescent material E B The maximum emission occurs in the range of 500-540 nm (polymethyl methacrylate (PMMA), λ max PMMA (E B It can represent (determined as). In one embodiment, phosphorescent material E B Its maximum emission λ is in the range of 490-530 nm. max PMMA (E B ) can be represented.

[0060] Phosphorescent materials Phosphorescent materials utilize intramolecular spin-orbit interactions (heavy atom effects) induced by metal atoms to obtain light emission from triplet atoms. Examples of such phosphorescent materials may include compounds represented by the general chemical formula EI shown below.

[0061] [ka] ···EI

[0062] In the chemical formula EI, M is selected from the group consisting of Ir, Pt, Au, Eu, Ru, Re, Ag, and Cu. n is an integer between 1 and 3. X and Y are, independently, monoanionic bidentate ligands. Examples of compounds represented by the chemical formula EI may include compounds represented by the general chemical formulas E-II or E-III shown below.

[0063]

Chem.

[0064]

Chem.

[0065] In chemical formulas E-II and E-III, X' is an aromatic ring carbon-bonded (C-bonded) to M, and Y' is a nitrogen (N)-containing complex that coordinates to M and forms a ring. X' and Y' are bonded, and X' and Y' can form a new ring. In chemical formula E-III, Z is a bidentate ligand having two oxygen atoms (O). In chemical formulas E-II and E-III, M is preferably Ir from the perspective of high efficiency and long lifespan.

[0066] In chemical formulas E-II and E-III, the aromatic ring X' is, for example, C6-C 30 aryl group, C6-C 16 aryl group, preferably C6-C 12 aryl group, more preferably C6-C 10 aryl group, and in each case, said X' can be optionally substituted with one or more substituents R E .

[0067] In chemical formulas E-II and E-III, Y' is, for example, C2-C 30 heteroaryl group, C2-C 25 heteroaryl group, preferably C2-C 20 heteroaryl group, more preferably C2-C 15 heteroaryl group, particularly preferably C2-C 10 heteroaryl group, and in each case, said Y' can be optionally substituted with one or more substituents R E . In addition, Y' is, for example, also a C1-C5 heteroaryl group that can be optionally substituted with one or more substituents R E .

[0068] In chemical formulas E-II and E-III, bidentate ligand Z, which has two oxygen (O) atoms, is, for example, a C2-C ligand with two oxygen atoms. 30 Bidentate ligand, C2-C with two oxygen atoms 25 Bidentate ligands, preferably C2-C having two oxygen atoms. 20 Bidentate ligands, more preferably C2-C having two oxygen atoms 15 Bidentate ligands, particularly preferably C2-C having two oxygen atoms 10 It is a bidentate ligand, and in each case, Z has one or more substituents R E It is selectively substituted for Z. Also, Z can be, for example, one or more substituents R. E It is also a C2-C5 bidentate ligand with two oxygen atoms that can be selectively substituted.

[0069] R E In each case, hydrogen, deuterium, and N(R) 5E )2, OR 5E , SR 5E , Si(R 5E )3, CF3, CN, halogen, One or more substituents R 5E C1-C that can be selectively substituted 40 Alkyl group, where one or more non-adjacent CH2 groups are R 5E C=CR 5E , C≡C, Si(R 5E )2, Ge(R 5E )2, Sn(R 5E )2, C=O, C=S, C=Se, C=NR 5E , P(=O)(R 5E ), SO, SO2, NR 5E , O, S or CONR 5E C1-C is replaced by 40 alkyl group; One or more substituents R 5E C1-C that can be selectively substituted 40 A thioalkoxy group, where one or more non-adjacent CH2 groups are R 5E C=CR 5E , C≡C, Si(R 5E)2, Ge(R 5E )2, Sn(R 5E )2, C=O, C=S, C=Se, C=NR 5E , P(=O)(R 5E ), SO, SO2, NR 5E , O, S or CONR 5E C1-C is replaced by 40 Thioalkoxy group; and One or more substituents R 5E C6-C is selectively replaceable. 60 Aryl group; one or more substituents R 5E C3-C that can be selectively replaced 57 It is possible to select from the group consisting of heteroaryl groups.

[0070] R 5E In each case, hydrogen, deuterium, and N(R) 6E )2, OR 6E , SR 6E , Si(R 6E )3, CF3, CN, F, One or more substituents R 6E C1-C that can be selectively substituted 40 Alkyl group, where one or more non-adjacent CH2 groups are R 6E C=CR 6E , C≡C, Si(R 6E )2, Ge(R 6E )2, Sn(R 6E )2, C=O, C=S, C=Se, C=NR 6E , P(=O)(R 6E ), SO, SO2, NR 6E , O, S or CONR 6E C1-C is replaced by 40 alkyl group; One or more substituents R 6E C6-C is selectively replaceable. 60 Aryl group; and One or more substituents R 6E C3-C that can be selectively replaced 57 It is possible to select from the group consisting of heteroaryl groups.

[0071] R 6EIn each case, hydrogen, deuterium, OPh, CF3, CN, F, A C1-C5 alkyl group in which one or more hydrogen atoms can be selectively and independently substituted with deuterium, CN, CF3, or F; A C1-C5 alkoxy group in which one or more hydrogen atoms can be selectively and independently substituted with deuterium, CN, CF3, or F; A C1-C5 thioalkoxy group in which one or more hydrogen atoms can be selectively and independently substituted with deuterium, CN, CF3, or F; C6-C alkyl groups that can be selectively substituted with one or more C1-C5 alkyl groups. 18 Aryl group; C3-C alkyl groups that can be selectively substituted with one or more C1-C5 alkyl groups. 17 heteroaryl group; N(C6-C 18 Aryl group) 2; N(C3-C 17 (heteroaryl group) 2; and N(C3-C 17 (heteroaryl group) (C6-C 18 It is possible to select from the group consisting of aryl groups.

[0072] Substituent R E , R 5E or R 6E These are one or more substituents R that are independent of each other and selectively. E , R 5E , R 6E And / or together with X′, Y′, and Z, they can form monocyclic or polycyclic, aliphatic, aromatic, heteroaromatic, and / or benzo-fused ring systems.

[0073] Examples of the compound represented by chemical formula E-II include Ir(ppy)3, Ir(ppy)2(acac), Ir(mppy)3, Ir(PPy)2(m-bppy), BtpIr(acac), Ir(btp)2(acac), Ir(2-phq)3, Hex-Ir(phq)3, Ir(fbi)2(acac), fac-tris(2-(3-p-xylyl)phenyl)pyridine iridium (III), Eu(dbm)3(Phen), Ir(piq)3, Ir(piq)2(acac), Ir(Fiq)2(acac), Ir(Flq)2(acac), Ru(dtb-bpy)3·2(PF6), Ir(2-phq)3, Ir(BT)2(acac), Ir(DMP)3, Ir(Mpq)3, Ir(phq)2tpy, fac-Ir(ppy)2Pc, Ir(dp)PQ2, Ir(Dpm)(Piq)2, Hex-Ir(piq)2(acac), Hex-Ir(piq)3, Ir(dmpq)3, Ir(dmpq)2(acac), FPQIrpic, and the like.

[0074] Other examples of the compound represented by chemical formula E-II include compounds represented by the following chemical formulas E-II-1 to E-II-11. In the structural formula, "Me" represents a methyl group.

[0075]

Chemical Formula

[0076]

Chemical Formula

[0077] Other examples of the compound represented by chemical formula E-III include compounds represented by the following chemical formulas E-III-1 to E-III-6. In the structural formula, "Me" represents a methyl group.

[0078]

Chemical Formula

[0079] Furthermore, iridium complexes described in US-A 2003 / 017361, US-A 2004 / 262576, WO 2010 / 027583, US-A 2019 / 245153, US-A 2013 / 119354 and / or US-A 2019 / 233451 are available. From the viewpoint of high efficiency of phosphorescent materials, Ir(ppy)3 and Hex-Ir(ppy)3 are available for green emission.

[0080] Small FWHM emitter material Small FWHM emitter S B It can have an emission spectrum that exhibits a full width at half maximum (FWHM) of approximately 0.25 eV or less (i.e., ≤0.25 eV).

[0081] Small FWHM emitter S B This can be selected to represent emission with a full width at half maximum (FWHM) of less than 0.25 eV, preferably less than 0.20 eV, and more preferably less than 0.15 eV in PMMA.

[0082] In one embodiment, a small FWHM emitter S B The emitter can be selected from the group consisting of fluorescent emitters and thermally activated delayed fluorescent emitters.

[0083] As used herein, the terms “fluorescent material” and “fluorescent emitter” are understood to be interchangeable.

[0084] According to the present invention, in a fluorescent material, ΔE corresponds to the energy difference between the lowest excited singlet state (S1) and the lowest excited triplet state (T1). ST The value is also 0.4eV or greater. As used herein, the terms “TADF material” and “TADF emitter” are to be understood to be interchangeable.

[0085] According to the present invention, in a TADF material, ΔE corresponds to the energy difference between the lowest excited singlet state (S1) and the lowest excited triplet state (T1). STThe value is less than 0.4 eV, preferably less than 0.3 eV, more preferably less than 0.2 eV, even more preferably less than 0.1 eV, or even more preferably less than 0.05 eV.

[0086] According to the present invention, ΔE corresponds to the energy difference between the lowest excited singlet state (S1) and the lowest excited triplet state (T1). ST Materials with a value of 0.4 eV are also TADF materials.

[0087] In one embodiment, a small FWHM emitter S B It is also an organic green fluorescent emitter.

[0088] Small FWHM emitter S B The element is a boron (B)-containing emitter. In one embodiment, a small FWHM emitter S B It is also a green boron-containing emitter. Small FWHM emitter S B Examples of green boron containing boron include compounds represented by the general chemical formula BI below. [ka] ···BI

[0089] The aforementioned B is boron, Ar 1 Ar 2 Ar 3 These are independently selected from the group consisting of aromatic rings and heteroaromatic rings in each case. Ar 1 Ar 2 Ar 3 These elements can be selectively linked to each other to form a ring. The Ar of the general chemical formula BI 1 Ar 2 Ar 3 Such aromatic rings include, for example, aryl rings having 6 to 30 carbon atoms, preferably aryl rings having 6 to 16 carbon atoms, more preferably aryl rings having 6 to 12 carbon atoms, and particularly preferably aryl rings having 6 to 10 carbon atoms.

[0090] Ar 1 Ar 2 Ar 3 Specific examples of aromatic rings include the benzene ring, which is a monocyclic system; the biphenyl ring, which is a bicyclic system; the naphthalene ring, which is a condensed bicyclic system; the terphenyl ring (m-terphenyl, o-terphenyl, or p-terphenyl), which is a tricyclic system; the acetanaphthylene ring, fluorene ring, phenalene ring, and phenanthrene ring, which are condensed tricyclic systems; the triphenylene ring, pyrene ring, and naphthacene ring, which are condensed tetracyclic systems; and the perylene ring and pentacene ring, which are condensed pentacyclic systems.

[0091] The Ar of the general chemical formula BI 1 Ar 2 Ar 3 Such heteroaromatic rings are, for example, heteroaryl rings having 2 to 30 carbon atoms, and the heteroaryl rings are heteroaryl rings having 2 to 25 carbon atoms, preferably heteroaryl rings having 2 to 20 carbon atoms, more preferably heteroaryl rings having 2 to 15 carbon atoms, and particularly preferably heteroaryl rings having 2 to 10 carbon atoms. Also, Ar of the general chemical formula BI 1 Ar 2 Ar 3 Such heteroaromatic rings are also heterorings that, for example, contain 1 to 5 heteroatoms selected from oxygen, sulfur, and nitrogen, in addition to carbon, as ring constituent atoms.

[0092] Ar 1 Ar 2 Ar 3Examples of heteroaromatic rings include pyrrole rings, oxazole rings, isoxazole rings, thiazole rings, isothiazole rings, imidazole rings, oxadiazole rings, thiadiazole rings, triazole rings, tetrazole rings, pyrazole rings, pyridine rings, pyrimidine rings, pyridazine rings, pyrazine rings, triazine rings, indole rings, isoindole rings, 1H-indazole rings, benzimidazole rings, benzoxazole rings, benzothiazole rings, and 1H-benzotriazole rings. This includes a quinoline ring, isoquinoline ring, sinnoline ring, quinazoline ring, quinoxaline ring, phthalazine ring, naphthyridine ring, purine ring, pteridine ring, carbazole ring, acridine ring, phenoxatiin ring, phenoxazine ring, phenothiazine ring, phenazine ring, indoridine ring, furan ring, benzofuran ring, isobenzofuran ring, dibenzofuran ring, thiophene ring, benzothiophene ring, dibenzothiophene ring, furazan ring, oxadiazole ring, and thiantrene ring.

[0093] Ar 1 Ar 2 Ar 3 In the aforementioned aromatic or heteroaromatic rings, one or more hydrogen atoms are one or more substituents R a It is replaceable with, The aforementioned R a These are, independently of each other, hydrogen, deuterium, and N(R) in their respective cases. 5 )2, OR 5 , SR 5 , Si(R 5 )3, CF3, CN, halogen, One or more substituents R 5 C1-C that can be selectively substituted 40 Alkyl group, where one or more non-adjacent CH2 groups are R 5 C=CR 5 , C≡C, Si(R 5 )2, Ge(R 5 )2, Sn(R 5 )2, C=O, C=S, C=Se, C=NR 5 , P(=O)(R 5 ), SO, SO2, NR 5, O, S or CONR 5 C1-C is replaced by 40 alkyl group; One or more substituents R 5 C1-C that can be selectively substituted 40 A thioalkoxy group, where one or more non-adjacent CH2 groups are R 5 C=CR 5 , C≡C, Si(R 5 )2, Ge(R 5 )2, Sn(R 5 )2, C=O, C=S, C=Se, C=NR 5 , P(=O)(R 5 ), SO, SO2, NR 5 , O, S or CONR 5 C1-C is replaced by 40 Thioalkoxy group; and One or more substituents R 5 C6-C is selectively replaceable. 60 Aryl group; one or more substituents R 5 C3-C that can be selectively replaced 57 It is possible to select from the group consisting of heteroaryl groups.

[0094] R 5 These are, independently of each other, hydrogen, deuterium, and N(R) in their respective cases. 6 )2, OR 6 , SR 6 , Si(R 6 )3, CF3, CN, F, One or more substituents R 6 C1-C that can be selectively substituted 40 Alkyl group, where one or more non-adjacent CH2 groups are R 6 C=CR 6 , C≡C, Si(R 6 )2, Ge(R 6 )2, Sn(R 6 )2, C=O, C=S, C=Se, C=NR 6 , P(=O)(R 6 ), SO, SO2, NR 6 , O, S or CONR 6 C1-C is replaced by 40 alkyl group; One or more substituents R 6 C6-C is selectively replaceable. 60 Aryl group; and one or more substituents R 6 C3-C that can be selectively replaced 57 It is possible to select from the group consisting of heteroaryl groups.

[0095] R 6 These are, independently of each other, hydrogen, deuterium, OPh, CF3, CN, F, in each case. A C1-C5 alkyl group in which one or more hydrogen atoms can be selectively and independently substituted with deuterium, CN, CF3, or F; A C1-C5 alkoxy group in which one or more hydrogen atoms can be selectively and independently substituted with deuterium, CN, CF3, or F; A C1-C5 thioalkoxy group in which one or more hydrogen atoms can be selectively and independently substituted with deuterium, CN, CF3, or F; C6-C alkyl groups that can be selectively substituted with one or more C1-C5 alkyl groups. 18 Aryl group; C3-C alkyl groups that can be selectively substituted with one or more C1-C5 alkyl groups. 17 heteroaryl group; N(C6-C 18 Aryl group)2;N(C3-C 17 Heteroaryl group)2, and N(C3-C 17 (heteroaryl group) (C6-C 18 It is possible to select from the group consisting of aryl groups.

[0096] Examples of compounds represented by the chemical formula BI include compounds represented by the general chemical formulas B-II, B-III, or B-IV listed below.

[0097] [ka] ···B-II

[0098] [ka] ···B-III

[0099] [ka] ...B-IV

[0100] Here, Y 1 , Y 2 , Y 3 In each case, R' is independently selected from the group consisting of NR', O, C(R')2, S, or Si(R')2, and each of the R's is independently selected from the group consisting of NR', O, C(R')2, One or more substituents R 6S A C1-C5 alkyl group selectively substituted; One or more substituents R 6S C6-C selectively substituted 60 Aryl group; and One or more substituents R 6S C3-C selectively substituted 57 Selected from the group consisting of heteroaryl groups, R 6S These are, independently of each other, hydrogen, deuterium, OPh, CF3, CN, F, in each case. A C1-C5 alkyl group in which one or more hydrogen atoms can be selectively substituted with deuterium, CN, CF3, or F, independently of each other; A C1-C5 alkoxy group in which one or more hydrogen atoms can be selectively substituted with deuterium, CN, CF3, or F, independently of each other; A C1-C5 thioalkoxy group in which one or more hydrogen atoms can be selectively substituted with deuterium, CN, CF3, or F, independently of each other; A C2-C5 alkenyl group in which one or more hydrogen atoms can be selectively substituted with deuterium, CN, CF3, or F, independently of each other; A C2-C5 alkynyl group in which one or more hydrogen atoms can be selectively substituted with deuterium, CN, CF3, or F, independently of each other; C6-C alkyl groups that can be selectively substituted with one or more C1-C5 alkyl groups. 18 Aryl group; C3-C alkyl groups that can be selectively substituted with one or more C1-C5 alkyl groups. 17 heteroaryl group; N(C6-C 18 Aryl group)2, N(C3-C 17 Heteroaryl group)2; and N(C3-C 17 (heteroaryl group) (C6-C 18 It is possible to select from the group consisting of aryl groups.

[0101] Substituent R a , R 5 , R 6 , R′ or R 6S These are one or more substituents R that are independent of each other and selectively. a , R 5 , R 6 , R′ or R 6S and / or aromatic ring or heteroaromatic ring Ar 1 Ar 2 and Ar 3 Together, they can form monocyclic or polycyclic, aliphatic, aromatic, heteroaromatic, and / or benzene-fused rings.

[0102] In one embodiment, the compound represented by chemical formula BI includes compounds represented by chemical formulas B-III-1, B-III-2, B-III-3, B-IV-1, B-IV-2, and B-IV-3.

[0103] [ka] ...B-III-1

[0104] [ka] ···B-III-2

[0105] [ka] ···B-III-3

[0106] [ka] ...B-IV-1

[0107] [ka] ...B-IV-2

[0108] [ka] ...B-IV-3

[0109] Here, the aforementioned structure can be selectively substituted by one or more substituents that selectively form additional rings.

[0110] In one embodiment, a small FWHM emitter S B It contains or consists of polycyclic aromatic compounds.

[0111] In one embodiment of the present invention, a small FWHM emitter S B It is also a near-range charge-transfer (NRCT) emitter. According to the present invention, the NRCT emitter exhibits a delayed component in the time-resolved photoluminescence spectrum and represents near-range HOMO-LUMO separation, as described by Hatakeyama et al. (Advanced Materials, 2016, 28(14):2777-2781, DOI:10.1002 / adma.201505491). In one embodiment, the NRCT emitter is also a TADF material.

[0112] Examples of compounds represented by the chemical formula B-III-I include the following structures.

[0113] [ka]

[0114] [ka]

[0115] [ka]

[0116] [ka]

[0117] In one embodiment, a small FWHM emitter S B This is also a green boron-containing NRCT emitter selected from the following group.

[0118] [ka]

[0119] Those skilled in the art will see that the light-emitting layer B is typically included in the organic electroluminescent element of the present invention. Preferably, the organic electroluminescent element includes at least one of the following layers: at least one light-emitting layer B, at least one anode layer A, and at least one cathode layer C.

[0120] Preferably, the anode layer A contains at least one component selected from the group consisting of indium tin oxide, indium zinc oxide, PbO, SnO, graphite, doped silicon, doped germanium, doped GaAs, doped polyaniline, doped polypyrrole, doped polythiophene, and mixtures of two or more of these.

[0121] Preferably, the cathode layer C contains at least one component selected from the group consisting of Al, Au, Ag, Pt, Cu, Zn, Ni, Fe, Pb, In, W, Pd, LiF, Ca, Ba, Mg, and mixtures or alloys of two or more of these.

[0122] Preferably, the light-emitting layer B is located between the anode layer A and the cathode layer C. Therefore, a common configuration is ABC. This, of course, does not preclude the presence of one or more selective additional layers. The additional layers may be present on each of the A, B, and / or C surfaces.

[0123] In one embodiment, the organic electroluminescent element includes at least the following layers: A) Anode layer A comprising at least one component selected from the group consisting of indium tin oxide, indium zinc oxide, PbO, SnO, graphite, doped silicon, doped germanium, doped GaAs, doped polyaniline, doped polypyrrole, doped polythiophene, and mixtures of two or more of these; B) Light-emitting layer B; and C) A cathode layer C comprising at least one component selected from the group consisting of Al, Au, Ag, Pt, Cu, Zn, Ni, Fe, Pb, In, W, Pd, LiF, Ca, Ba, Mg, and mixtures or alloys of two or more of these.

[0124] The light-emitting layer B may be located between the anode layer A and the cathode layer C.

[0125] In one embodiment, when the organic electroluminescent element is an OLED, the organic electroluminescent element selectively includes the following layer structure: A) An example anode layer A containing indium tin oxide (ITO); HTL (Hole Transport Layer) B) A light-emitting layer B according to the present invention, as described herein; ETL (Electron Transport Layer ETL); and C) A cathode layer comprising Al, Ca and / or Mg as an example. Preferably, the order of the layers here is A-HTL-B-ETL-C.

[0126] Furthermore, the organic electroluminescent element may selectively include one or more protective layers to protect it from damaging exposure to harmful substances in the environment, such as moisture, vapor, and / or gases.

[0127] Preferably, the anode layer A is located on the surface of the substrate. The substrate may also be formed from any material or a composition thereof. Most often, a glass slide is used as the substrate. Alternatively, a thin metal layer (e.g., copper, gold, silver, or aluminum film), or a plastic film or plastic slide may be used. This can allow for an even higher level of flexibility. The anode layer A is composed of a material from which a nearly (essentially) transparent film can be obtained. Since at least one of the two electrodes must be (essentially) transparent in order to allow light emission from the OLED, one of the anode layer A or cathode layer C is transparent. Preferably, the anode layer A contains a large amount of transparent conductive oxide (TCO) or is composed of transparent conductive oxide (TCO).

[0128] Such anode layer A may also include, as an example, indium tin oxide, aluminum zinc oxide, fluorine-doped tin oxide, indium zinc oxide, PbO, SnO, zirconium oxide, molybdenum oxide, vanadium oxide, tungsten oxide, graphite, doped Si, doped Ge, doped GaAs, doped polyaniline, doped polypyrrole, and / or doped polythiophene.

[0129] Particularly preferred is that the anode layer A is (essentially) indium tin oxide (ITO) (e.g., (InO3) 0.9 (SnO2) 0.1The anode layer A is composed of the following. The roughness of the anode layer A due to the transparent conductive oxide (TCO) can also be mitigated by using a hole injection layer (HIL). The HIL facilitates the injection of similar charge carriers (e.g., holes) in such a way that the transport of similar charge carriers from the TCO to the hole transport layer (HTL) is promoted. The hole injection layer (HIL) may also contain poly-3,4-ethylenedioxythiophene (PEDOT), polystyrene sulfonic acid (PSS), MoO2, V2O5, CuPC, or CuI, in particular a mixture of PEDOT and PSS. The hole injection layer (HIL) can also prevent the diffusion of metal from the anode layer A to the hole transport layer (HTL). For example, the HIL is poly-3,4-ethylenedioxythiophene:polystyrene sulfonic acid (PEDOT:PSS), poly-3,4-ethylenedioxythiophene (PEDOT), 4,4′,4"-tris[phenyl(m-tolyl)amino]triphenylamine (mMTDATA), 2,2′,7,7′-tetrakis(n,n-diphenylamino)-9,9′-spirobifluorene (Spiro-TAD), N1,N1′-(biphenyl-4,4′-diyl)bis(N1-phenyl-N4,N4-di-m-tolylbenzene-1,4-diamine (DNTPD), N,N′-nis-(1-naph It is also composed of thalenyl)-N,N′-bis-phenyl-(1,1′-biphenyl)-4,4′-diamine (NPB), N,N′-diphenyl-N,N′-di-[4-(N,N-diphenylamino)phenyl]benzidine (NPNPB), N,N,N′,N′-tetrakis(4-methoxyphenyl)benzidine (MeO-TPD), 1,4,5,8,9,11-hexaazatriphenylene-hexacarbonnitrile (HAT-CN), and / or N,N′-diphenyl-N,N′-bis-(1-naphthyl)-9,9′-spirobifluorene-2,7-diamine (Spiro-NPD).

[0130] Adjacent to the anode layer A or hole injection layer (HIL), typically, a hole transport layer (HTL) is located. Here, any hole transport compound can be used. Exemplarily, electron-rich heteroaromatic compounds such as triarylamines and / or carbazoles can also be used as hole transport compounds. The HTL can reduce the energy barrier between the anode layer A and the luminescent layer B (which acts as the luminescent layer (EML)). The hole transport layer (HTL) is also an electron barrier layer (EBL). Preferably, the hole transport compound has a relatively high energy level in the triplet state T1. For example, the hole transport layer (HTL) is tris(4-carbazolyl-9-ylphenyl)amine (TCTA), poly(4-butylphenyl-diphenylamine) (poly-TPD), poly(4-butylphenyl-diphenylamine) ([alpha]-NPD), 4,4′-cyclohexyllidene-bis[N,N-bis(4-methylphenyl)benzeneamine] (TAPC), 4,4′,4"-tris[2-naphthyl(phenyl)-amino]triphenylamine (2-TNATA), Spiro-TAD, DNTPD, NPB, NPNPB, MeO-TPD, HAT-CN and / or 9,9′-diphenyl-6-(9-phenyl-9 The HTL may also contain a star-shaped heterocycle such as H-carbazole-3-yl)-9H,9′H-3,3′-bicarbazole (TrisPcz). The HTL may also contain a p-doped layer composed of inorganic or organic dopants within the organic hole transport matrix. Examples of inorganic dopants include transition metal oxides such as vanadium oxide, molybdenum oxide, or tungsten oxide. Examples of organic dopants include tetrafluorotetracyanoquinodimethane (F4-TCNQ), copper-pentafluorobenzoic acid (Cu(I)pFBz), or transition metal complexes.

[0131] For example, EBL is 1,3-bis(carbazole-9-yl)benzene (mCP), 9,9′-bis([1,1′-biphenyl]-3-yl)-3,3′-bi-9H-carbazole (CAS 1352040-89-1); TCTA, 2-TNATA, 3,3-di(9H-carbazole-9-yl)biphenyl (mCBP), 9-[3-(dibenzofuran-2-yl)phenyl]-9H-carbazole, 9-[3-(dibenzofuran-2-yl)phenyl]-9H-carbazole, 9-[3-(dibenzothiophen-2-yl)phenyl]-9H-carbazole, 9-[3,5-bis( This also includes 2-dibenzofuranyl)phenyl]-9H-carbazole, 9-[3,5-bis(2-dibenzothiophenyl)phenyl]-9H-carbazole, Tris-Pcz, 9-(4-tert-butylphenyl)-3,6-bis(triphenylsilyl)-9H-carbazole (CzSi), 3′,5′-di-(N-carbazolyl)-[1,1′-biphenyl]-2-carbonitrile (DCPBN; CAS 1918991-70-4), 3-(N-carbazolyl)-N-phenylcarbazole (NCNPC), and / or N,N′-dicarbazolyl-1,4-dimethylbenzene (DCB).

[0132] For host compounds, the energy of the initial excited triplet state T1 is measured from the onset of the time-gated emission spectrum at 77 K, typically with a delay time of 1 ms and an integration time of 1 ms, measured in a polymethyl methacrylate (PMMA) film containing 10 wt% of the host, unless otherwise noted.

[0133] For small FWHM emitters, the energy of the initial excited triplet state T1 is measured from the start of the time-gate emission spectrum at 77K, typically with a delay time of 1 ms and an integration time of 1 ms, in a PMMA film containing 1 wt% emitter, unless otherwise noted.

[0134] For phosphorescent compounds, the energy of the initial excited triplet state T1 is measured from the start of the time-gate emission spectrum at room temperature, typically with a delay time of 1 ms and an integration time of 1 ms, in a PMMA film containing 10 wt% emitter, unless otherwise noted.

[0135] Orbital and excited state energies can also be determined by experimental methods known to those skilled in the art. Experimentally, the highest occupied orbital E HOMO The energy can also be determined by cyclic voltammetry measurements with an accuracy of 0.1 eV, or by methods well known to those skilled in the art. LUMO The energy of is E HOMO +E gap Calculated by, the above E gap This is determined as follows:

[0136] In the case of the host compound, unless otherwise stated, the luminescence initiation of a film containing 10 wt% of the PMMA host corresponds to the energy of the first excited singlet state S1 at E gap It is used as such.

[0137] For small FWHM emitters, unless otherwise stated, the emission start of a film with 1 wt% small FWHM emitters of PMMA corresponds to the energy of the first excited singlet state S1 at E gap It is used as such.

[0138] In the case of organic phosphorescent emitters, unless otherwise stated, the emission start of a film containing 10 wt% PMMA host corresponds to the energy of the first excited singlet state S1 at E gap It is used as such.

[0139] Any electron transporter can be used in the electron transport layer (ETL). Illustratively, electron-deficient compounds such as benzimidazole, pyridine, triazole, oxadiazole (e.g., 1,3,4-oxadiazole), phosphine oxide, and sulfone can be used. Illustratively, the electron transporter ETM is also a star-shaped heterocycle such as 1,3,5-tri(1-phenyl-1H-benzo[d]imidazole-2-yl)phenyl (TPBi). The ETM is also, exemplified, 2,9-bis(naphthalene-2-yl)-4,7-diphenyl-1,10-phenanthroline (NBphen), aluminum-tris(8-hydroxyquinoline) (Alq3), diphenyl-4-triphenylsilylphenylphosphine oxide (TSPO1), 2,7-di(2,2′-bipyridine-5-yl)triphenyl (BPyTP2), dibenzo[b,d]thiophen-2-yltriphenylsilane (Sif87), dibenzo[b,d]thiophen-2-yl)diphenylsilane (Sif88), 1,3-bis[3,5-di(pyridine-3-yl)phenyl]benzene (BmPyPhB) and / or 4,4′-bis-[2-(4,6-diphenyl-1,3,5-triazinyl)]-1,1′-biphenyl (BTB). Selectively, the electron transport layer may also be doped with a substance such as 8-hydroxyquinoline latritium (Liq). Selectively, a second electron transport layer may be located between the electron transport layer and the cathode layer C. The electron transport layer (ETL) can also block holes. Alternatively, a hole blocking layer (HBL) may be introduced.

[0140] [ka] HBL may include, for example, HBM1.

[0141] 2,9-Dimethyl-4,7-diphenyl-1,10-phenanthroline=basocupproine (BCP), bis(8-hydroxy-2-methylquinoline)-(4-phenylphenoxy)aluminum (BAlq), 2,9-bis(naphthalene-2-yl)-4,7-diphenyl-1,10-phenanthroline (NBphen), aluminum-tris(8-hydroxyquinoline)(Alq3), diphenyl-4-triphenylsilylphenylphosphine oxide (TSPO1), 2,4,6-tris(biphenyl-3-yl)-1,3,5-triazine (T2T), 2, It also contains 4,6-tris(triphenyl-3-yl)-1,3,5-triazine (T3T), 2,4,6-tris(9,9′-spirobifloren-2-yl)-1,3,5-triazine (TST), 2,4-diphenyl-6-(3′-triphenylsilylphenyl)-1,3,5-triazine (DTST), 2,8-bis(4,6-diphenyl-1,3,5-triazinyl)dibenzofuran (DTDBF) and / or 1,3,5-tris(N-carbazol)benzol / 1,3,5-tris(carbazole)-9-yl)benzene (TCB / TCP).

[0142] Adjacent to the electron transport layer (ETL), the cathode layer C may be located. For example, the cathode layer C may contain or consist of a metal (e.g., Al, Au, Ag, Pt, Cu, Zn, Ni, Fe, Pb, LiF, Ca, Ba, Mg, In, W, or Pd) or a metal alloy. For practical reasons, the cathode layer C may also consist of an (essentially) opaque metal such as Mg, Ca, or Al. Alternatively, or even further, the cathode layer C may also contain graphite and / or carbon nanotubes (CNTs). Alternatively, the cathode layer C may also consist of nanoscale silver wire.

[0143] The OLED may optionally further include a protective layer between the electron transport layer (ETL) D and the cathode layer C (also designated as the electron injection layer (EIL)). The protective layer may contain lithium fluoride, cesium fluoride, silver, 8-hydroxyquinoline tritium (Liq), Li2O, BaF2, MgO and / or NaF.

[0144] As used herein, unless otherwise specifically defined in a particular context, the hue designation of emitted and / or absorbed light is as follows: Purple: Wavelength range >380~420nm; Dark blue: Wavelength range >420~475nm; Sky blue: Wavelength range >475~500nm; Green: Wavelength range >500~560nm; Yellow: Wavelength range >560~580nm; Orange color: Wavelength range >580~620nm; Red: Wavelength range of >620~800nm. Unless otherwise mentioned, for small FWHM emitters, such a hue is the maximum luminescence λ of a PMMA film with a 1 wt% emitter. max PMMA This represents the maximum luminescence λ of the PMMA film, which is 10% for phosphorescent materials and host materials, unless otherwise mentioned. max PMMA It represents.

[0145] Therefore, for example, a dark blue emitter has a maximum emission λ in the range of 420-475 nm. max PMMA It has a sky-blue emitter with a maximum emission λ in the range of 475-500 nm. max PMMA It has a green emitter with a maximum emission λ in the range of 500-560 nm. max PMMA It has a red emitter with a maximum emission λ in the range of 620-800 nm. max PMMA It holds.

[0146] Therefore, one embodiment of the present invention is i) 1000 cd / m 2 ii) an OLED exhibiting an external quantum efficiency of over 10%, preferably over 13%, more preferably over 15%, even more preferably over 18%, or even more preferably over 20%, ii) an OLED exhibiting maximum emission at 490nm to 600nm, preferably 500nm to 580nm, more preferably 510nm to 560nm, even more preferably 520nm to 540nm, and / or iii) a constant current density J0 = 15mA / cm² 2 This relates to OLEDs that exhibit an LT95 value exceeding 100 hours, preferably exceeding 200 hours, more preferably exceeding 400 hours, even more preferably exceeding 750 hours, or even more preferably exceeding 1000 hours.

[0147] One embodiment of the present invention relates to an OLED that emits light at a distinct color point. According to the present invention, the OLED can emit light in a narrow emission band (small full width at half maximum (FWHM)). In one embodiment, the OLED according to the present invention can emit light having an FWHM of a main emission peak of less than 0.25 eV, preferably less than 0.20 eV, more preferably less than 0.15 eV, or even less than 0.13 eV.

[0148] One embodiment of the present invention relates to an OLED that emits light having CIEx and CIEy close to the CIEx (=0.170) and CIEy (=0.797) color coordinates of primary green (CIEx=0.170 and CIEy=0.797) as defined by ITU-R Recommendation BT.2020 (Rec.2020), and the OLED is suitable for use in UHD (Ultra High Definition) displays such as UHD-TVs. In this context, the term “close” refers to the range of CIEx and CIEy coordinates provided at the end of this paragraph. In commercial applications, typically, top-emitting elements (with transparent top electrodes) are used, while the test elements used throughout the present invention represent bottom-emitting elements (with transparent bottom electrodes and substrate). Accordingly, a further aspect of the present invention relates to an OLED in which the lower light emission represents a CIEx color coordinate of 0.15 to 0.45, preferably 0.15 to 0.35, more preferably 0.15 to 0.30, even more preferably 0.15 to 0.25, or more preferably 0.15 to 0.20, and / or a CIEy color coordinate of 0.60 to 0.92, preferably 0.65 to 0.90, more preferably 0.70 to 0.88, even more preferably 0.75 to 0.86, or more preferably 0.79 to 0.84.

[0149] One embodiment of the present invention relates to an OLED that emits light having CIEx and CIEy close to the CIEx (=0.265) and CIEy (=0.65) color coordinates of primary green (CIEx=0.265 and CIEy=0.65) as defined by DCIP3. In this context, the term “close” refers to the range of CIEx and CIEy coordinates provided at the end of this paragraph. In commercial applications, typically, top-emitting elements (with transparent top electrodes) are used, while the test elements used throughout the present invention represent bottom-emitting elements (with transparent bottom electrodes and substrate). Accordingly, one embodiment of the present invention relates to an OLED in which the lower light emission represents i) a CIEx color coordinate of 0.2 to 0.45, preferably 0.2 to 0.35, more preferably 0.2 to 0.30, even more preferably 0.24 to 0.28, or more preferably 0.25 to 0.27, and / or ii) a OLED in which the CIEy color coordinate of 0.60 to 0.9, preferably 0.6 to 0.8, more preferably 0.60 to 0.70, even more preferably 0.62 to 0.68, or more preferably 0.64 to 0.66.

[0150] As used throughout this application, the terms “aryl” and “aromatic” are understood in their broadest sense to refer to any monocyclic or polycyclic aromatic moiety. In one embodiment, the aryl residue is C6-C6 18 It is also an aryl residue. In one embodiment, the aryl residue is C6~C 14 Aryl residues, or C6-C 10It is also an aryl residue. More specific definitions are provided in the paragraphs for each compound described above. Unless otherwise stated, aryls are also selectively substituted by one or more substituents, which are further illustrated throughout this application. Thus, the term “arylene” means a divalent residue that has two binding sites to other molecular structures and acts as a linker structure. As used throughout this application, the terms “heteroaryl” and “heteroaromatic” are also understood in their broadest sense to mean any monocyclic heteroaromatic, bicyclic heteroaromatic, or polycyclic heteroaromatic moiety containing at least one heteroatom, in particular those having 1 to 3 heteroatoms per aromatic ring. In one embodiment, the heteroaryl residue is C2-C 17 It is also an aryl residue. In one embodiment, the heteroaryl residue is C2~C 13 Aryl residues, or C2-C 13 It is also an aryl residue.

[0151] Examples of heteroaromatic compounds include pyrrole, furan, thiophene, imidazole, oxazole, thiazole, triazole, pyrazole, pyridine, pyrazine, and pyrimidine. Unless otherwise stated, heteroaryls are selectively substituted by one or more substituents, as further exemplified throughout this application. Accordingly, the term "heteroarylene" refers to a divalent residue that possesses two binding sites to other molecular structures and acts as a linker structure.

[0152] Unless otherwise specified, percentages represent weight percentages ((weight / weight), (w / w), wt.).

[0153] As used throughout this application, the term “alkyl” is also understood in its broadest sense as both linear alkyl residues and branched alkyl residues. Preferred alkyl residues contain 1 to 15 carbon atoms. Exemplary alkyl residues include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, and tert-butyl. Unless otherwise indicated, alkyls are also selectively substituted by one or more substituents, as further exemplified throughout this application. Thus, the term “alkylene” means a divalent residue that possesses two binding sites to other molecular structures and acts as a linker structure. Unless otherwise indicated, the term “substituted” is also understood in its broadest sense as used in this application, particularly in relation to aryl, arylene, heteroaryl, alkyl, etc. Preferably, such substitutions are C1-C 20 Alkyl alkyl group, C7-C 19 Alkali and C6-C 18 This refers to residues selected from the group consisting of aryl groups. Therefore, preferably, there is no charged moiety, and more preferably, there is no active group in such substitution. It can be seen that hydrogen can be substituted for deuterium in each case.

[0154] Unless otherwise specified, any layer in the various embodiments may also be deposited by any preferred method. In the context of the present invention, the layer comprises the light-emitting layer B and is selectively manufactured by a liquid process (also referred to as a “film process,” “fluid process,” “solution process,” or “solvent process”). This means that the components contained in each layer are applied in liquid form to a portion of the surface of the device. Preferably, in the context of the present invention, the layer comprises the light-emitting layer B and is also manufactured by spin coating. A thin and (essentially) homogeneous layer can be obtained by such a method, which is well known to those skilled in the art.

[0155] Alternatively, in the context of the present invention, the layer comprises an emissive layer B and can also be manufactured by other liquid-based methods such as casting (e.g., drop casting) and rolling methods, as well as printing methods (e.g., inkjet printing, gravure printing, blade coating). This is carried out selectively in an inert atmosphere (e.g., a nitrogen atmosphere).

[0156] In one embodiment, in the context of the present invention, the layer may also be manufactured by any other method well known to those skilled in the art, including, but not limited to, vacuum processing methods well known to those skilled in the art, such as thermal (cavity) evaporation, organic vapor deposition (OVPD), and organic vapor jet printing (OVJP).

[0157] When the layer is manufactured by a liquid process, a solution containing the components of the layer (i.e., one or more host compounds H for the light-emitting layer B of the present invention) is used. P and typically one or more phosphorescent materials E B , at least a small FWHM emitter S B and selectively one or more other host compounds H N The solvent may further contain a volatile organic solvent. The volatile organic solvent is selectively selected from the group consisting of tetrahydrofuran, dioxane, chlorobenzene, diethylene glycol diethyl ether, 2-(2-ethoxyethoxy)ethanol, gamma butyrolactone, N-methylpyrrolidinone, ethoxyethanol, xylene, toluene, anisole, phenethole, acetonitrile, tetrahydrothiophene, benzonitrile, pyridine, trihydrofuran, triarylamine, cyclohexanone, acetone, propylene carbonate, ethyl acetate, benzene, and propylene glycol monoethyl ether acetate (PGMEA). In addition, combinations of two or more solvents may be used. After application in liquid form, the layer is subsequently dried and / or cured by any technical means, exemplary, under ambient conditions, increased temperature (e.g., about 50°C or about 60°C) or reduced pressure.

[0158] Selectively, an organic electroluminescent element (e.g., OLED) is also, exemplary, essentially a white organic electroluminescent element or a blue organic electroluminescent element. Exemplarily, the white organic electroluminescent element comprises at least one (dark) blue emitter compound, as well as green light (e.g., phosphorescent material E B Or a small FWHM emitter S B ) and / or comprising one or more emitter compounds that emit red light. Then, energy transfer may selectively occur between two or more of the aforementioned compounds.

[0159] Organic electroluminescent elements can form thin layers with overall thicknesses of 5 mm or less, 2 mm or less, 1 mm or less, 0.5 mm or less, 0.25 mm or less, 100 μm or less, or 10 μm or less.

[0160] Organic electroluminescent elements (e.g., OLEDs) are small (e.g., 5mm). 2 Below, or more specifically, 1 mm 2 Medium size (e.g., 0.5-20cm), having the following surface characteristics. 2 (Having a surface area of ​​the range) or large (e.g., 20 cm) 2 (Having a larger surface area). The organic electroluminescent elements (e.g., OLEDs) according to the present invention can be used as large-area lighting elements to selectively generate screens, such as luminescent wallpapers, luminescent window frames or glass, luminescent labels, luminescent posers, and flexible screens or displays. Beyond common applications, organic electroluminescent elements (e.g., OLEDs) can be used, exemplary, as luminescent films, "smart packaging" labels, or innovative design elements. They can also be used for cell detection and inspection (e.g., biolabeling).

[0161] One of the primary purposes of an organic electroluminescent element is the generation of light. Therefore, the present invention further includes the step of providing an organic electroluminescent element according to the present invention and a method for generating light in a desired wavelength range.

[0162] Therefore, another aspect of the present invention is, (i) the step of providing an organic electroluminescent element according to the present invention; and (ii) The present invention relates to a method for generating light in a desired wavelength range, which includes the step of applying an electric current to the organic electroluminescent element. Another aspect of the present invention relates to a method for manufacturing an organic electroluminescent element by assembling the aforementioned elements. The present invention also relates to a method for generating green light using the organic electroluminescent element. [Examples]

[0163] The examples and claims further illustrate the present invention. Circulating voltage-current method In dichloromethane, or a suitable solvent, and a suitable supporting electrolyte (e.g., 0.1 mol / l tetrabutylammonium hexafluorophosphate), 10 -3 The cyclic voltammogram of a solution with an organic molecule concentration of mol / l is measured. The measurement is performed at room temperature and in a nitrogen atmosphere using a three-electrode assembly (working electrode and relative electrode: Pt wire, reference electrode: Pt wire), with FeCp2 / FeCp2 as the internal standard. + Correction is performed using [this method]. HOMO data was corrected using perocene as an internal standard related to saturated calomel electrodes (SCE).

[0164] Density function theory calculation The molecular structure was optimized using the BP86 function and the RI (Resolution of Identity) approach. Excitation energies were calculated using the (BP86) optimized structure with the TD-DFT (Time-Dependent DFT) method. Orbital energies and excited state energies were calculated using the B3LYP function. The Def2-SVP basic set and m4-grid were used for numerical integration. The Turbomole program package was used for all calculations.

[0165] photophysical measurements Sample preparation: Spin coating Equipment: Spin150, SPS euro The concentration of the sample dissolved in a suitable solvent is 10 mg / ml. Program: 1) 3 seconds at 400 U / min at 1000 Up m / s; 20 seconds at 1000 U / min. 3) 10 seconds at 4000 U / min at 1000 Up m / s. After coating, the film was dried at 70°C for 1 minute.

[0166] Photoluminescence spectroscopy and time-correlated single-photon coefficient (TCSPC) Steady-state emission spectroscopy is recorded using a Model FluoroMax-4 (Horiba Scientific) equipped with a 150W xenon-Arc lamp, excitation and emission monochromators, Hamamatsu R928 photoelectron booster tubing, and a time-correlated single-photon counting option. Standard correction fits are used to correct the emission and excitation spectra.

[0167] The excited state lifetime is determined using the same system employing the TCSPC method, along with the FM-2013 equipment and the Horiba Yvon TCSPC hub.

[0168] Excitation light source: NanoLED 370 (Wavelength: 371nm, Pulse duration: 1.1ns) NanoLED 290 (Wavelength: 294nm, Pulse duration: <1ns) SpectraLED 310 (wavelength: 314nm) SpectraLED 355 (wavelength: 355nm) Data analysis (exponential fitting) is performed using the DataStation and DAS6 analysis software suites. The fit is determined using the chi-squared test.

[0169] Photoluminescence quantum yield measurement For photoluminescence quantum yield (PLQY) measurements, the Absolute PL quantum yield measurement system C9920-03G (Hamamatsu Photonics) was used. Quantum yield and CIE coordinates were measured using software U6039-05 version 3.6.0.

[0170] The maximum emission is expressed in nm, the quantum yield Φ is expressed in %, and the CIE coordinates are expressed in x,y values.

[0171] PLQY is determined using the following protocol: 1) Quality Assurance: Anthracene (known concentration) in ethanol will be used as the standard. 2) Excitation wavelength: The maximum absorption of the organic molecule is measured, and this wavelength is used to excite the molecule. 3) Measurement: Quantum yield is measured for solution or film samples in a nitrogen atmosphere. The yield is calculated using the following formula.

[0172]

number

[0173] The aforementioned n photon indicates the number of photons, and Int indicates the intensity.

[0174] Production and characterization of organic electroluminescent elements OLED elements containing organic molecules according to the present invention can also be manufactured by vacuum deposition. When a layer contains one or more compounds, the weight percentage of one or more compounds is indicated in %. Since the total weight percentage value is 100%, if no value is specified, the proportion of the compound is the difference between the specified value and 100%.

[0175] Unoptimized OLEDs are characterized by an external quantum efficiency (%) that depends on the intensity and current, calculated using the light detected by the photodiode after measuring the electroluminescence spectrum using standard methods.

[0176] The lifespan of an OLED element is derived from the change in brightness while operating at a constant current density. The LT50 value corresponds to the time when the measured brightness has decreased to 50% of the initial brightness, similarly, LT80 corresponds to the time when the measured brightness has decreased to 80% of the initial brightness, and LT95 corresponds to the time when the measured brightness has decreased to 95% of the initial brightness.

[0177] Accelerated lifetime measurements are performed (e.g., by applying increased current density). For example, 500 cd / m². 2 In this case, the LT80 value is determined using the following formula:

[0178]

number

[0179] L0 indicates the initial brightness at the applied current density. The value represents the average of multiple pixels (typically 2 to 8), and the standard deviation between those pixels is provided. The figure shows the data series for a single OLED pixel.

[0180] Experimental results [ka]

[0181] [ka]

[0182] [ka]

[0183] [ka]

[0184] [ka]

[0185] [ka]

[0186] [ka] HBM1 (Hole Blocking Material)

[0187] [Table 1]

[0188] Here, LUMO CV This is the energy of the lowest unoccupied orbit, determined by the circulating voltage-current method. a The emission spectrum was recorded from an Ir(ppy)3 solution in chloroform. b The emission spectrum is P in dichloromethane. B Recorded from a 0.001 mg / mL solution of -2.

[0189] [Table 2]

[0190] To evaluate the results of the present invention, comparative experiments were conducted with only the composition of the light-emitting layer (6) being different. P and H N The proportion remained constant throughout the comparative experiment.

[0191] [Table 3]

[0192] Here, mCBP is H P Used as, host N1 is H N Used as, Ir(ppy)3 is E B Used as such, emitter S1 is S B It is used as such. The percentage is by weight.

[0193] [Table 4]

[0194] [Table 5]

[0195] Here, mCBP is H P Used as, host N1 is H N Used as, Ir(ppy)3 is E B Used as such, emitter S1 is S B It is used as such. The percentage is by weight.

[0196] [Table 6]

[0197] [Table 7]

[0198] [Table 8]

[0199] [Table 9]

[0200] Here, mCBP is H P Used as, host N1 is H N Used as, Ir(ppy)3 is E B Used as such, emitter S2 is S B It is used as such. Percentages are It is expressed as a weight percentage.

[0201] [Table 10]

[0202] [Table 11]

[0203] Here, host P1 is H P Used as, host N1 is H N Used as, Ir(ppy)3 is E B Used as such, emitter S2 is S B It is used as such. The percentage is by weight.

[0204] [Table 12]

[0205] mCBP to H P As used, 7% Ir(ppy)3 is E BFor all H-type elements used, a 16% relative lifetime extension was observed for emitter S1 (from 1.00 to 1.16) and a 140% relative lifetime extension was observed for emitter S2 (from 1.00 to 2.40). Meanwhile, efficiency remained almost constant (approximately EQE=23%), and FWHM decreased by 33% for emitter S1 (from 0.30eV to 0.20eV) and by 46% for emitter S2 (from 0.30eV to 0.16eV). For green application, the color points improved to CIEx=0.26, CIEy=0.66 for emitter S1 and CIEx=0.32, CIEy=0.65 for emitter S2. Host P1 is H P As used, 7% Ir(ppy)3 is E B For all H-type elements used as such, a 10% relative lifetime extension was observed for emitter S1 (from 1.00 to 1.10), and a 60% relative lifetime extension was observed for emitter S2 (from 1.00 to 1.60). Meanwhile, efficiency remained almost constant (approximately EQE=24%), FWHM decreased by 30% for emitter S1 (from 0.30 to 0.21) and by 45% for emitter S2 (from 0.31 to 0.17). Due to the application of green, the color points improved to CIEx=0.26 and CIEy=0.66 for emitter S1, and to CIEx=0.32 and CIEy=0.65 for emitter S2.

[0206] Host P1 is H P Used as E B Use as and emitter S2 as S B For all H-type elements used, a 44% relative lifetime extension (from 1.00 to 1.40) was observed. Meanwhile, efficiency remained nearly constant (approximately EQE=24%), and FWHM decreased by 33% (from 0.30 to 0.21). For green application, the color point improved to CIEx=0.26 and CIEy=0.66.

[0207] [Table 13] Here, host P2 is H PUsed as, host N2 is H N Used as, E B -I is E B Used as such, emitter S2 is S B It is used as such. The percentage is by weight.

[0208] [Table 14]

[0209] Comparing P-type elements and H-type elements, host P1 is H P As used, host N2 is H N Used as, 7% E B -I to E B Use as and emitter S2 as S B For H-type elements used in this way, a 59% extension of relative lifetime (from 1.00 to 1.59) was observed, an improvement in efficiency (from 23.2% to 26.1%) was observed, FWHM was reduced by 45% (from 0.29 eV to 0.16 eV), and a color point for green application was achieved.

[0210] The relative lifetime was determined for all device experiments based on the individual LT95 lifetime measured at 1200 nits.

[0211] Results for emitter S3

[0212] JPEG0007927600000053.jpg7586 Emitter S3 (Small FWHM Emitter S B )

[0213] [Table 15]

[0214] Here, LUMO CV This is the energy of the lowest unoccupied orbit, determined by the circulating voltage-current method.

[0215] [Table 16]

[0216] Here, host P1 is H P Used as, host N1 is H N Used as, Ir(ppy)3 is E B Used as such, emitter S3 is S B It is used as such. The percentage is by weight.

[0217] Comparing the JPEG0007927600000056.jpg 32135P-type element and the H-type element, host P1 is H P As used, 7% Ir(ppy)3 is E B As used, emitter S3 is S B For H-type elements used as such, a 34% extension of relative lifetime (from 1.00 to 1.34) was observed, an improvement in efficiency (from 23.2% to 24.7%) was observed, FWHM was reduced by 42% (from 0.31 eV to 0.18 eV), and a color point for green application was achieved.

[0218] The relative lifetime was determined for all device experiments based on the individual LT95 lifetime measured at 1200 nits.

Claims

1. An organic electroluminescent element including a light-emitting layer B, The aforementioned light-emitting layer B is (i) Lowest excited singlet state energy level S1 Ｐ and the lowest excited triplet state energy level T1 Ｐ , having energy E ＨＯＭＯ (H Ｐ ) highest occupied molecular orbital HOMO (H Ｐ ), and energy E ＬＵＭＯ (H Ｐ ) lowest unoccupied molecular orbital LUMO (H Ｐ ), a host material H containing a carbazole ring Ｐ , and (ii) Lowest excited singlet state energy level S1 Ｅ and the lowest excited triplet state energy level T1 Ｅ It has energy E ＨＯＭＯ (E Ｂ ) has the highest occupied orbit HOMO (E Ｂ ), and energy E ＬＵＭＯ (E Ｂ LUMO (E) has the lowest orbital Ｂ ) Phosphorescent material E Ｂ and, (iii) Lowest excited singlet state energy level S1 Ｓ and the lowest excited triplet state energy level T1 Ｓ It has energy E ＨＯＭＯ (S Ｂ ) has the highest occupied orbit HOMO (S Ｂ ), and energy E ＬＵＭＯ (S Ｂ LUMO (S) has the lowest idle orbit Ｂ ) has a small FWHM emitter S, which is a DABNA derivative. Ｂ and, The host material H P is a compound selected from the following group of compounds or a mixture of two or more compounds. The phosphorescent material E Ｂ The energy is transmitted to the small half-width emitter S Ｂ It transmits to and contains or consists of the structure of the following chemical formula I, The aforementioned small FWHM emitter S B is a thermally activated delayed fluorescence (TADF) emitter that emits light with maximum emission in the range of 500 nm to 560 nm and has an emission spectrum with a FWHM of 0.25 eV or less. Organic electroluminescent elements: [Compound group] 【Chemistry 1】 【Chemistry 2】 【Transformation 3】 【Chemistry 4】 【Transformation 5】 [Chemical formula I] 【Transformation 6】 ...I In chemical formula I, M is selected from the group consisting of Ir, Pt, Au, Eu, Ru, Re, Ag, and Cu. n is an integer between 1 and 3. X and Y are independently monoanionic bidentate ligands. The following relationships, represented by equations (1) to (4), apply to organic electroluminescent elements: T1 Ｅ >S1 Ｓ Equation (1) T1 Ｐ >T1 Ｓ Formula (2) T1 Ｐ >T1 Ｅ Formula (3) T1 Ｐ >S1 Ｅ Equation (4).

2. The organic electroluminescent element has a maximum emission wavelength of λ from 500 nm to 560 nm. ｍａｘ The organic electroluminescent element according to claim 1, showing (D).

3. The small FWHM emitter S Ｂ The organic electroluminescent element according to claim 1, which emits light having a maximum emission in the range of 510 nm to 550 nm.

4. The organic electroluminescent element has a maximum emission wavelength of λ from 510 nm to 550 nm. ｍａｘ An organic electroluminescent element according to any one of claims 1 to 3, showing (D).

5. The aforementioned light-emitting layer B is (iv) Lowest excited singlet state energy level S1 Ｎ , the lowest excited triplet state energy level T1 Ｎ Energy E ＨＯＭＯ (H Ｎ ) has the highest occupied orbit HOMO (H Ｎ ), and energy E ＬＵＭＯ (H Ｎ LUMO (H) has the lowest available orbit Ｎ ) Host material H Ｎ It further includes, The relationships expressed by the following equations (2N), (3N), and (4N) were applied. T1 Ｎ >T1 Ｓ Equation (2N) T1 Ｎ >T1 Ｅ Equation (3N) T1 Ｎ >S1 Ｅ Equation (4N) An organic electroluminescent element according to any one of claims 1 to 4.

6. The small FWHM emitter S Ｂ S1 Ｓ and T1 Ｓ ΔE corresponds to the energy difference with ＳＴ The ΔE has a value, ＳＴ The organic electroluminescent element according to any one of claims 1 to 5, wherein the value is less than 0.4 eV.

7. The light-emitting layer B may optionally be: (iv) Further comprising a host material H N having the lowest excited singlet state energy level S1 N, the lowest excited triplet state energy level T1 N, the highest occupied orbital HOMO (H N) having energy E HOMO (H N), and the lowest unoccupied orbital LUMO (H N) having energy E LUMO (H N), The relationships expressed by the following equations (2N), (3N), and (4N) apply. T1 N > T1 S Formula (2N) T1 N > T1 E formula (3N) T1 N > S1 E Formula (4N), The aforementioned light-emitting layer B is (i) 22 to 70% by weight of the host material H Ｐ and, (ii) 0 to 70% by weight of the host material H Ｎ and, (iii) 5 to 10% by weight of the phosphorescent material E Ｂ and, (iv) 1 to 5% by weight of the emitter S Ｂ An organic electroluminescent element according to any one of claims 1 to 6, comprising the above.

8. The aforementioned light-emitting layer B is (i) 10 to 30% by weight of the host material H Ｐ and, (ii) 40 to 74% by weight of the host material H Ｎ and, (iii) 15 to 30% by weight of the phosphorescent material E Ｂ and, (iv) 1 to 5% by weight of the emitter S Ｂ The organic electroluminescent element according to claim 5, comprising the above.

9. A method for generating green light having a wavelength of 500 to 560 nm, (i) the step of providing an organic electroluminescent element according to any one of claims 1 to 8, (ii) A method comprising the step of applying an electric current to the organic electroluminescent element.

Images