WO2019218270A1

WO2019218270A1 - Organic light-emitting diode and electronic device

Info

Publication number: WO2019218270A1
Application number: PCT/CN2018/087094
Authority: WO
Inventors: Yasunori Kijima
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2018-05-16
Filing date: 2018-05-16
Publication date: 2019-11-21
Also published as: JP6995204B2; JP2021507482A; CN111344878A; CN111344878B

Abstract

There is a desire to improve the quantum efficiency of a self-standing light-emitting type of organic light-emitting diode that includes an organic layer. Provided is an organic light-emitting diode including a first electrode; a second electrode; an emission layer provided between the first electrode and the second electrode; and a semi-crystalized organic layer that is provided between the first electrode and the emission layer, and has a particles diameter less than or equal to 100 nm. Also provided is an electronic device including the organic light-emitting diode.

Description

ORGANIC LIGHT-EMITTING DIODE AND ELECTRONIC DEVICE

BACKGROUND

1. TECHNICAL FIELD

The present invention relates to an organic light-emitting diode and an electronic device.

2. RELATED ART

A conventional self-standing light-emitting type of organic light-emitting diode is known that includes an organic layer, as shown in Patent Document 1, for example.

Patent Document 1: Japanese Patent Application Publication No. 2003-115389

However, conventional organic light-emitting diodes suffer from problems in that sufficient quantum efficiency cannot be realized.

SUMMARY

According to a first aspect of the present invention, provided is an organic light-emitting diode comprising a first electrode; a second electrode; an emission layer provided between the first electrode and the second electrode; and a semi-crystalized organic layer that is provided between the first electrode and the emission layer, and has a particles diameter less than or equal to 100 nm.

According to a second aspect of the present invention, provided is an electronic device comprising the organic light-emitting diode of the first aspect.

The summary clause does not necessarily describe all necessary features of the embodiments of the present invention. The present invention may also be a sub-combination of the features described above.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 shows an exemplary configuration of the organic light-emitting diode 100.

Fig. 2A shows an exemplary configuration of the organic layer 10 according to the first embodiment.

Fig. 2B shows an exemplary configuration of the organic light-emitting diode 100 according to the second embodiment.

Fig. 2C shows an exemplary configuration of the organic light-emitting diode 100 according to the third embodiment.

Fig. 2D shows an exemplary configuration of the organic light-emitting diode 100 according to the fourth embodiment.

Fig. 2E shows an exemplary configuration of the organic light-emitting diode 100 according to the fifth embodiment.

Fig. 3 shows exemplary light propagation modes in the organic light-emitting diode 100.

Fig. 4 is a schematic view of the layered structure of the organic light-emitting diode 100.

Fig. 5A shows an example of observation results of the morphology of the semi-crystalized organic layer 86.

Fig. 5B shows an example of observation results of the morphology of the semi-crystalized organic layer 86.

Fig. 5C shows an example of observation results of the morphology of the semi-crystalized organic layer 86.

Fig. 5D shows an example of observation results of the morphology of the semi-crystalized organic layer 86.

Fig. 5E shows an example of observation results of the morphology of the semi-crystalized organic layer 86.

Fig. 5F shows an example of observation results of the morphology of the semi-crystalized organic layer 86.

Fig. 5G shows examples of the average particle diameters of the semi-crystalized organic layers 86 in all figures from Fig. 5A to Fig. 5F.

Fig. 6A shows an exemplary configuration of an organic layer 510 according to a comparative example.

Fig. 6B shows examples of light propagation modes in the organic light-emitting diode 500.

Fig. 7 is a contribution rate of the power reduction result for each of red, green, and blue.

Fig. 8 shows an exemplary EL spectrum of the organic light-emitting diode 100.

Fig. 9A shows an example of a viewing angle property of the organic light-emitting diode 100.

Fig. 9B shows an example of a viewing angle property of the organic light-emitting diode 100.

Fig. 9C shows an example of a viewing angle property of the organic light-emitting diode 100.

Fig. 9D shows an example of a viewing angle property of the organic light-emitting diode 100.

Fig. 9E is a table showing average values of the viewing angle properties of the organic light-emitting diode 100.

Fig. 10A shows the lifetime measurement results of the luminance decay of the organic light-emitting diode 100.

Fig. 10B shows the lifetime measurement results of the driving voltage change the change over time of the applied voltage of the organic light-emitting diode 100.

Fig. 11A shows an exemplary case in which the organic light-emitting diode 100 is adopted in a portable terminal 200.

Fig. 11B shows an exemplary case in which the organic light-emitting diode 100 is adopted in a portable terminal 210.

Fig. 11C shows an exemplary case in which the organic light-emitting diode 100 is adopted in a portable terminal 220.

Fig. 11D shows an exemplary case in which the organic light-emitting diode 100 is adopted in a notebook computer 230.

Fig. 11E shows an exemplary case in which the organic light-emitting diode 100 is adopted in a television apparatus 240.

Fig. 11F shows an exemplary case in which the organic light-emitting diode 100 is adopted in smart glasses 250.

Fig. 11G shows an exemplary case in which the organic light-emitting diode 100 is adopted in a smart watch 260.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

Hereinafter, some embodiments of the present invention will be described. The embodiments do not limit the invention according to the claims, and all the combinations of the features described in the embodiments are not necessarily essential to means provided by aspects of the invention.

Fig. 1 shows an exemplary configuration of an organic light-emitting diode 100. The organic light-emitting diode 100 includes an organic layer 10, an anode 20, a cathode 30, an encapsulation layer 40, an encapsulation layer 50, and a sealing substrate 60.

The organic layer 10 uses an organic electroluminescence (EL) phenomenon to emit light. The organic layer 10 is provided between the anode 20 and the cathode 30, and a prescribed current flows through the organic layer 10. The organic layer 10 generates light with a prescribed wavelength by recombining electrons and holes.

The anode 20 is provided on the bottom surface of the organic layer 10. The anode 20 may also have the function of a reflective layer. In this way, the light emitting efficiency of the organic light-emitting diode 100 is improved. The material of the anode 20 may include a single metal element such as silver (Ag) , aluminum (Al) , chromium (Cr) , titanium (Ti) , iron (Fe) , cobalt (Co) , nickel (Ni) , molybdenum (Mo) , copper (Cu) , tantalum (Ta) , tungsten (W) , platinum (Pt) , neodymium (Nd) , or gold (Au) , or an alloy of any of these metals.

As an example, the anode 20 includes a first transparent electrode, a reflective electrode, and a second transparent electrode. The material of the anode 20 is an ITO/Ag alloy/ITO, for example. ITO is a transparent electrode made of indium tin oxide. The Ag alloy used may be an Ag, Pa, and Cu alloy in the interest of stability, but as long as the electrode has high reflectivity, an element made of an Al-type alloy can be used, for example. The ITO, Ag alloy, and ITO may have film thicknesses of 50 nm, 150 nm, and 10 nm, respectively.

The cathode 30 is provided on the top surface of the organic layer 10. The cathode 30 is provided opposite the anode 20. In the case of a top-emission structure, it is necessary for the light to be emitted from the cathode side, and therefore the cathode 30 must have transparency. If the cathode 30 is formed by a transparent electrode such as ITO or IZO, it is possible for the film thickness thereof to be on the order of hundreds of nanometers, but as long as in-plane conductivity or an equipotential surface can be formed, it is possible to select any film thickness according to the panel size and resolution. If a metal electrode is used, a large film thickness is undesirable since it would obstruct the transparency, and so the film thickness of the cathode 30 may be less than or equal to 15 nm. The material of the cathode 30 may include a single metal element such as aluminum (Al) , magnesium (Mg) , calcium (Ca) , or sodium (Na) , or an alloy of any of these metals. More specifically, the material of the cathode 30 may be an alloy of magnesium and silver (MgAg alloy) or an alloy of aluminum (Al) and lithium (Li) (AlLi or stacked its bilayer) . Any type or composition of electrode can be selected as the cathode 30.

The encapsulation layer 40 is provided on the cathode 30. The encapsulation layer 40 may be a single layer or may be multi-layered. The encapsulation layer 40 preferably has a strong ability to block moisture, oxygen, and other impurities that have a negative effect on the organic layer 10. For example, the encapsulation layer 40 includes a silicon nitride (typically Si ₃N ₄) film, a silicon oxide (typically SiO ₂) film, a silicon oxide nitride (SiN _xO _y composition in which X > Y) film, a silicon nitride oxide (SiO _xN _y composition in which X > Y) film, a thin film that is primarily carbon such as DLC (Diamond Like Carbon) , a CNT (Carbon Nanotube) film, or the like. As an example, the encapsulation layer 40 is formed using plasma CVD.

The encapsulation layer 50 is provided on the encapsulation layer 40. The encapsulation layer 50 seals the organic layer 10 and the encapsulation layer 40. The encapsulation layer 50 may have the same kind of material as the encapsulation layer 40, or may have a different kind of material. The encapsulation layer 50 may be formed by either an insulating material or a conductive material. The insulating material may be crystalline or amorphous and may be an inorganic insulating material such as amorphous silicon (α-Si) , silicon carbide (SiC) , silicon nitride (Si-Nx) , amorphous carbon (α-C) , silicon oxide (SiOx) , or silicon nitride oxide (SiNxOy) , for example. Examples of the conductive material include indium tin oxide (ITO) , indium zinc oxide (InZnO) , indium titanium zinc oxide (ITZO) , and the like.

The sealing substrate 60 is provided on the encapsulation layer 50. The sealing substrate 60 seals the organic layer 10 along with the encapsulation layer 40 and the encapsulation layer 50. The sealing substrate 60 has a material that transparently passes emission light generated by the organic layer 10. For example, the sealing substrate 60 is formed of a material such as transparent glass that transparently passes the emission light generated by the organic layer 10. Furthermore, the sealing substrate 60 may be provided with a light shielding film serving as a color filter or black matrix.

In the organic light-emitting diode 100 of the embodiment, the organic layer 10 includes a semi-crystalized organic (SCO) layer 86 that is described further below, thereby converting plasmon loss into a substrate mode. If conversion into the substrate mode can be achieved, it is possible to realize extraction as an external mode. In addition to or instead of this, by including the semi-crystalized organic layer 86, the organic light-emitting diode 100 scatters the emission light and extracts the emission light as the external mode. By extracting the plasmon loss as the external mode, the organic light-emitting diode 100 can reduce the plasmon loss and improve the luminance. Furthermore, by scattering the emission light, the organic light-emitting diode 100 can improve the light extraction efficiency and improve the luminance.

Fig. 2A shows an exemplary configuration of the organic layer 10 according to a first embodiment. The organic layer 10 of the embodiment includes an emission layer (EML) 15, a hole transport region 70, and an electron transport region 80. Each layer in the organic layer 10 may be a single layer or may be multi-layered. The cathode 30 and the anode 20 of the first embodiment are respectively examples of a first electrode and a second electrode.

The emission layer 15 is provided between the anode 20 and the cathode 30. The emission layer 15 emits light as a result of excitons generated by the recombination of holes and electrons injected from the anode 20 and the cathode 30. The emission layer 15 emits light having a wavelength that corresponds to the constituent material. For example, if the emission layer 15 is to emit blue light, the emission layer 15 includes ADN (Anthracene Dinaphthyl) as a host material and 2.5%by weight of 4, 4'-bis [2- {4- (N, N-diphenylamino) phenyl} vinyl] biphenyl (DPAVBi) mixed in as a guest material that emits blue light. The thickness of the emission layer 15 is 30 nm for example. However, the materials and the thickness of the emission layer 15 are not particularly limited.

The hole transport region 70 is provided between the emission layer 15 and the anode 20. The hole transport region 70 includes a hole transport layer (HTL) 74 and injects holes into the emission layer 15. The hole transport region 70 of the embodiment includes a hole injection layer (HIL) 72 and an electron barrier layer (EBL) 76. However, the hole transport region 70 does not need to include the hole injection layer 72 and the electron barrier layer 76.

The hole injection layer 72 functions as a buffer layer for increasing the efficiency of the hole injection into the emission layer 15 and also for preventing leaks. As an example, the hole injection layer 72 has an aromatic amine structure. The hole injection layer 72 may include any one of 4, 4', 4"-tris (3-methylphenylphenylamino) triphenylamine (m-MTDATA) and 4, 4', 4"-tris (2-naphthylphenylamino) triphenylamine (2-TNATA) . As an example, the film thickness of the hole injection layer 72 is greater than or equal to 5 nm. For example, the film thickness of the hole injection layer 72 is 10 nm. The hole injection layer 72 may be doped with a P-type dopant, but does not need to be doped with a P-type dopant.

The hole transport layer 74 is provided between the emission layer 15 and the anode 20. The hole transport layer 74 increases the efficiency of the hole transport into the emission layer 15. As an example, the hole transport layer 74 has an aromatic amine structure. The hole transport layer 74 may include bis [ (N-naphthyl) -N-phenyl] benzidine (α-NPD) . As an example, the film thickness of the hole transport layer 74 may be greater than or equal to 5 nm and less than or equal to 130 nm. For example, the film thickness of the hole transport layer 74 is 10 nm. The hole transport layer 74 may be doped with a P-type dopant, but does not need to be doped with a P-type dopant.

The electron barrier layer 76 prevents the electrons injected from the electron transport region 80 into the emission layer 15 from moving to the hole transport region 70 side. The electron barrier layer 76 can adjust the carriers of the emission layer 15 and increase the probability of recombination with carriers of opposite polarity. The material of the electron barrier layer 76 may be selected according to the materials of the emission layer 15 and the hole transport layer 74. For example, the electron barrier layer 76 is a material with a higher LUMO level (i.e. a lower electron affinity) than the emission layer 15. In this way, the electron barrier layer 76 can restrict the removal of electrons from the emission layer 15 and improve the recombination probability. Furthermore, the electron barrier layer 76 is preferably formed of a material whose HOMO level is close to that of the hole transport layer 74. In this way, the charge injection barrier is reduced.

The electron transport region 80 is provided between the emission layer 15 and the cathode 30. The electron transport region 80 includes an electron transport layer (ETL) 84, and injects electrons into the emission layer 15. Furthermore, the electron transport region 80 includes a semi-crystalized organic layer 86. The electron transport region 80 of the embodiment includes a hole barrier layer (HBL) 82 and an electron injection layer (EIL) 88. However, the electron transport region 80 does not need to include the hole barrier layer 82 and the electron injection layer 88.

The hole barrier layer 82 prevents the electrons injected from the hole transport region 70 into the emission layer 15 from moving to the electron transport region 80 side. The hole barrier layer 82 can adjust the carriers of the emission layer 15 and increase the probability of recombination with carriers of the opposite polarity. The material of the hole barrier layer 82 may be selected according to the materials of the emission layer 15 and the electron transport layer 84. For example, the hole barrier layer 82 is a material with a lower HOMO level (i.e. a greater ionization potential) than the emission layer 15. In this way, the hole barrier layer 82 can restrict the removal of holes from the emission layer 15 and improve the recombination probability. Furthermore, the hole barrier layer 82 is preferably formed of a material whose LUMO level is close to that of the electron transport layer 84. In this way, the charge injection barrier is reduced.

The electron transport layer 84 is provided between the cathode 30 and the emission layer 15. The electron transport layer 84 increases the efficiency of the electron transport into the emission layer 15. As long as the electron transport layer 84 is a material with electron transport properties, the material of the electron transport layer 84 is not particularly limited. The electron transport layer 84 may include an aryl pyridine derivative, a benzimidazole derivative, or the like. The electron transport layer 84 may be doped with an N-type dopant, but does not need to be doped with an N-type dopant. Furthermore, the electron transport layer 84 may include alkali metals, alkaline earth metals, rare earth metals and oxides thereof, complex oxides, fluorides, carbonates, and the like.

The semi-crystalized organic layer 86 may have both a semi-crystalline region and an amorphous region. The semi-crystalline region of the semi-crystalized organic layer 86 exists including a state of clusters or crystals having a certain distribution, and has distributed particle diameters. Therefore, the particle diameter of the semi-crystalized organic layer 86 refers to the average particle diameter of the semi-crystalline region of the semi-crystalized organic layer 86. The particle diameter and shape of the semi-crystalized organic layer 86 can be adjusted according to the organic molecule design.

The semi-crystalized organic layer 86 is provided between the emission layer 15 and an electrode. The semi-crystalized organic layer 86 is provided between the cathode 30 and the emission layer 15. The semi-crystalized organic layer 86 may be provided between the emission layer 15 and the anode 20. Furthermore, the semi-crystalized organic layer 86 may be provided both between the emission layer 15 and the anode 20 and between the emission layer 15 and the cathode 30. Providing the semi-crystalized organic layer 86 near the interface between the organic layer 10 and each electrode is effective for reducing the plasmon loss occurring at the interfaces between the organic layer 10 and each electrode.

The semi-crystalized organic layer 86 may have a substituent that adds crystallinity to a material having the same mother skeleton with a material that is the same as the material that can be used for the electron transport layer 84, or may have semi-crystallinity with a completely different mother skeleton. The semi-crystal here refers to an organic material with properties such that the molecular interaction is smaller than in a crystalline organic material, there is little difference in the electron mobility between the semi-crystalline portion and the amorphous portion, and, as a semi-crystalline layer, charge concentration does not occur in the crystalline portion that generally has a property of the electron mobility being high. When charge concentration is centralized in the semi-crystalized portion, luminance uniformity of the light emitting surface cannot be maintained and dark spots or the like appear due to the charge concentration, which is a problem in terms of reliability. The semi-crystalized organic layer 86 has a material with an electron transport property. The specific materials of the semi-crystalized organic layer 86 are described further below. The semi-crystalized organic layer 86 may be layered using a vacuum evaporation or a wet process such as printing in the same manner as the other layers of the organic layer 10, and there is no need to provide a new specialized step.

The film thickness of the semi-crystalized organic layer 86 may be less than or equal to 30 nm, less than or equal to 20 nm, or less than or equal to 10 nm. By making the film thickness of the semi-crystalized organic layer 86 less than or equal to 30 nm, it is possible for the light emitting surface to realize uniform light emission. The film thickness of the semi-crystalized organic layer 86 may be suitably changed according to the wavelength of the emission light emitted by the emission layer 15.

The semi-crystalized organic layer 86 can change the direction of the energy vector of the plasmon loss occurring near the boundary between the organic layer 10 and the cathode 30, recombine the plasmon loss as light, and extract the light as the external mode. The conversion from the plasmon loss to the external mode includes a case in which the plasmon loss is extracted as the external mode through another mode, such as the substrate mode. In this way, the semi-crystalized organic layer 86 reduces the drop in the external quantum efficiency (EQE) caused by the plasmon loss. In the embodiment, the plasmon loss energy is converted into light that is radiated to the outside, and therefore the luminance of the organic light-emitting diode 100 is improved. The particle diameter of the semi-crystalized organic layer 86 may be suitably selected according to the wavelength of the light emitted by the emission layer 15. The particle diameter of the semi-crystalized organic layer 86 is less than or equal to 100 nm. The particle diameter of the semi-crystalized organic layer 86 may be less than or equal to 50 nm or less than or equal to 20 nm. For example, the particle diameter of the semi-crystalized organic layer 86 is greater than or equal to 2 nm and less than or equal to 20 nm. As a result of the semi-crystalized organic layer 86 having such a particle diameter, the surface area of the cathode 30 becomes larger.

Here, it is often the case that each configurational element made from an organic material is formed with an amorphous material in order to preserve the in-plane uniformity of the electric field intensity. Alternatively, even if the material itself is crystalline, a material that becomes an amorphous thin film when a thin film is formed is used. When an organic material crystalizes, the lifetime of the organic light emitting element is reduced due to the concentration of current. For example, amorphous materials having chemically and physically stable structures have been selected, such that the electron injection layer and the electron transport layer do not crystallize during deposition. In this way, crystalline material was not selected for the electron transport layer, but on the other hand, the semi-crystalized organic layer 86 is a layer provided to reduce the plasmon loss and has a feature of being formed of a semi-crystalline material.

The electron injection layer 88 is provided between the cathode 30 and the semi-crystalized organic layer 86. The electron injection layer 88 of the embodiment is provided in contact with the semi-crystalized organic layer 86. The electron injection layer 88 is a layer for transferring electrons from the cathode 30 to the organic layer 10. As an example, the electron injection layer 88 may include at least one of LiF and Li ₂O. The film thickness of the electron injection layer 88 is preferably made small enough that the unevenness of the crystal of the semi-crystalized organic layer 86 remains at the interface with the cathode 30 as well. For example, the film thickness of the electron injection layer 88 is 1 nm. As an example, the electron injection layer 88 is a material that is doped with an N-type dopant and has an electron transport property, and has a film thickness of 5 nm. If the semi-crystalized organic layer 86 has the function of the electron injection layer 88, the electron injection layer 88 is unnecessary. As an example, the electron injection layer 88 is a mixed layer including an organic material with an electron transport property, such as 8-hydroxyquinoline aluminum (Alq ₃) , and a reducible metal such as an alkali metal or an alkaline earth metal.

The film thicknesses of the hole transport region 70 and the electron transport region 80 are designed to satisfy optical conditions that enable the light generated by the organic layer 10 to be extracted to the outside. With each film thickness as an optical condition in the design of elements and the light extraction efficiency as an interference condition, each film thickness is determined according to the element design regarding the positional relationship of the respective films to include at least two locations where the light extraction efficiency becomes large. Accordingly, the film thickness of the electron transport region 80 may be smaller or larger than the film thickness of the hole transport region 70. The film thickness of the hole transport region 70 is the total of the film thicknesses of the hole injection layer 72, the hole transport layer 74, and the electron barrier layer 76. The film thickness of the electron transport region 80 is the total of the film thicknesses of the hole barrier layer 82, the electron transport layer 84, the semi-crystalized organic layer 86, and the electron injection layer 88.

In this way, the organic light-emitting diode 100 preferably achieves a balance between the electron supplying function and the hole supplying function. By achieving a balance between the supplies of electrons and holes to the emission layer 15, the organic light-emitting diode 100 can improve the current efficiency and the light emitting lifetime.

The organic light-emitting diode 100 of the embodiment includes the semi-crystalized organic layer 86 between the emission layer 15 and the cathode 30. However, the organic light-emitting diode 100 may include the semi-crystalized organic layer 86 between the emission layer 15 and the anode 20. In this case, the semi-crystalized organic layer 86 has a hole transporting property and functions as the hole injection layer 72.

The organic light-emitting diode 100 of the first embodiment is described as having a top-emission type of basic structure. However, the basic structure of the organic light-emitting diode 100 may be a bottom-emission type. In this case, the film thicknesses of the anode 20 and the cathode 30 may be suitably changed according to the basic structure of the organic light-emitting diode 100.

For example, if the organic light-emitting diode 100 is a top-emission type, the cathode 30 has a film thickness that enables the emission light of the organic light-emitting diode 100 to transparently pass. On the other hand, if the organic light-emitting diode 100 is a bottom-emission type, the anode 20 generally uses a transparent electrode of ITO, IZO, or the like in most cases, but if a metal electrode or the like is used, the anode 20 has a thickness enabling the emission light of the organic light-emitting diode 100 to transparently pass. There are cases where the cathode 30 uses a reflective electrode, and it is more efficient to be used in a state where the transparency is low and near zero, such that the emission light does not leak from the cathode 30 side. For both top-emission and bottom-emission types, in most cases, the electrode opposite the electrode on the light extraction side, i.e. the opposite electrode, uses an electrode with high reflectivity and low transparency, but if this electrode has a certain amount of transparency, it is possible to extract emission light from both sides, thereby realizing a structure known as a transparent display. The invention according to the embodiment can be used as a transparent display as well. The organic light-emitting diodes 100 according to other embodiments may also be adopted as both top-emission types and bottom-emission types.

Here, the organic light-emitting diode 100 has a resonator structure in which the emission light is resonated between the anode 20 and the cathode 30 and extracted. In this way, the organic light-emitting diode 100 improves the color purity of the extracted light and improves the intensity of the extracted light near the center wavelength of resonance. The film thickness of each layer of the organic layer 10 in the organic light-emitting diode 100 may be adjusted to satisfy the following expression.

Expression 1: (2L) /λ+Φ/ (2π) = m

The optical distance L is the optical distance between a first end surface E1 and a second end surface E2 of the resonator. The first end surface E1 refers to a reflective end surface on the organic layer 10 side of the anode 20. The second end surface E2 refers to a reflective end surface on the organic layer 10 side of the cathode 30. Φ is the sum (Φ = Φ ₁+Φ ₂) (rad) of a phase shift Φ ₁ of the reflected light occurring at the first end surface E1 and a phase shift Φ ₂ of the reflected light occurring at the second end surface E2. λ is a peak wavelength of the emission light spectrum that is desired to be extracted from the second end surface E2 side. m is an integer selected such that L becomes positive. In Expression 1, the units of L and λ should be the same. For example, L and λ are set to have (nm) units.

The organic light-emitting diode 100 of the present example has a resonant structure in which the emission light generated by the emission layer 15 is resonated and extracted from the second end surface E2 side (i.e. the cathode 30 side) . The optical distance L may be set in a manner to realize the smallest positive value that satisfies Expression 1.

Furthermore, an adjustment is made in the organic light-emitting diode 100 such that the optical distance L ₁ satisfies Expression 2 shown below and the optical distance L ₂ satisfies Expression 3 shown below. The optical distance L ₁ is the optical distance between the maximum light emission position of the organic layer 10 and the first end surface E1. The optical distance L ₂ is the optical distance between the maximum light emission position and the second end surface E2. The maximum light emission position is the position on the emission layer 15 at which the light emission intensity is greatest. For example, if light is emitted at the interfaces on both the anode 20 side and the cathode 30 side of the organic layer 10, the maximum light emission position is whichever of these interfaces has the greater light emission intensity.

Expression 2: L ₁ = tL ₁+a ₁

(2tL ₁) /λ = -Φ ₁/ (2π) +m ₁

In Expression 2, tL ₁ is the theoretical optical distance between the first end surface E1 and the maximum light emission position. a ₁ is a correction amount based on the light emission distribution in the organic layer 10. λ is the peak wavelength of the light emission spectrum that is desired to be extracted. Φ ₁ is a phase shift (rad) of the reflected light occurring at the first end surface E1. m ₁ is 0 or an integer. Expression 2 is such that, when the emission light heading in the direction of the anode 20 among the emission light generated by the organic layer 10 is reflected and returned by the first end surface E1, the phase of this returned light and the phase at the time of the light emission are the same, so that a stronger relationship with the emission light heading toward the cathode 30 among the emitted light is established.

Expression 3: L ₂ = tL ₂+a ₂

(2tL ₂) /λ = -Φ ₂/ (2π) +m ₂

In Expression 3, tL ₂ is the theoretical optical distance between the second end surface E2 and the maximum light emission position. a ₂ is a correction amount based on the light emission distribution in the organic layer 10. λ is the peak wavelength of the light emission spectrum that is desired to be extracted. Φ ₂ is a phase shift (rad) of the reflected light occurring at the second end surface E2. m ₂ is 0 or an integer. Expression 3 is such that, when the emission light heading in the direction of the cathode 30 among the emission light generated by the organic layer 10 is reflected and returned by the second end surface E2, the phase of this returned light and the phase at the time of the light emission are the same, so that a stronger relationship with the emission light heading toward the anode 20 among the emitted light is established.

In the organic light-emitting diode 100 of the first embodiment, by forming the electron transport region 80 such that the film thickness thereof is greater than the film thickness of the hole transport region 70, it is possible to design the organic light-emitting diode 100 such that m ₁ > m ₂ in Expression 2 and Expression 3. In this way, the light extraction efficiency can be increased.

The theoretical optical distance tL ₁ of Expression 2 and the theoretical optical distance tL ₂ of Expression 3 are theoretical values whereby, in a case where it is assumed that the light emission region does not expand, the phase change amount at the first end surface E1 or the second end surface E2 and the phase change amount caused by the progression of the emission light cancel out and the phase of the returned light and the phase at the time of emission become the same. However, it should be noted that the light emission portion usually expands, and therefore Expression 2 and Expression 3 have the correction amounts a ₁ and a ₂, which are based on the light emission distribution, added thereto.

The correction amounts a ₁ and a ₂ differ according to the light emission distribution. If the maximum light emission position is on the cathode 30 side of the emission layer 15 and the light emission distribution expands to the anode 20 side from the maximum light emission position, or if the maximum light emission position is on the anode 20 side of the emission layer 15 and the light emission distribution expands to the cathode 30 side from the maximum light emission position, the correction amounts a ₁ and a ₂ are calculated as shown in the following expression.

Expression 4: a ₁ = b (log _e (s) )

a ₂ = -a ₁

b is such that 2n ≤ b ≤ 6n, if the light emission distribution of the emission layer 15 expands in a direction of the anode 20 from the maximum light emission position. Furthermore, b is such that -6n ≤ b ≤ -2n, if the light emission distribution of the emission layer 15 expands in a direction of the cathode 30 from the maximum light emission position. n is the average refractive index between the first end surface E1 and the second end surface E2 at the peak wavelength λ of the light emission spectrum desired to be extracted. s is a physical property value (1/e attenuation distance) relating to the light emission distribution in the emission layer 15.

As an example, the organic light-emitting diode 100 of the first embodiment includes the anode 20 with a film thickness of 210 nm, the hole injection layer 72 with a film thickness of 7 nm, the hole transport layer 74 with a film thickness of 122 nm, the electron barrier layer 76 with a film thickness of 7 nm, the emission layer 15 with a film thickness of 30 nm, the hole barrier layer 82 and electron transport layer 84 with a total film thickness of 11 nm, the semi-crystalized organic layer 86 with a film thickness of 10 nm, the electron injection layer 88 with a film thickness of 1.0 nm, and the cathode 30 with a film thickness of 11 nm. It should be noted that the film thickness of each layer is an example, and is not limited to the above. The anode 20 may be a film of ITO/Ag alloy/ITO with respective film thicknesses of 50 nm, 150 nm, and 10 nm. As long as the total film thickness of the hole barrier layer 82, the electron transport layer 84, and the semi-crystalized organic layer 86 in the first embodiment is 21 nm, the respective film thicknesses of these layers are not particularly limited.

Fig. 2B shows an exemplary configuration of the organic light-emitting diode 100 according to a second embodiment. The organic light-emitting diode 100 of the second embodiment differs from the organic light-emitting diode 100 of the first embodiment in that the film thickness of the electron transport region 80 is greater than the film thickness of the hole transport region 70. In the description of the second embodiment, focus is placed on points that are different from the first embodiment. The cathode 30 and the anode 20 of the second embodiment are respectively examples of a first electrode and a second electrode.

The film thickness of the electron transport region 80 is greater than the film thickness of the hole transport region 70. By making the film thickness of the electron transport region 80 greater than the film thickness of the hole transport region 70, it becomes more difficult for electrons to be injected into the emission layer 15 from the cathode 30 as excess carriers. When electrons become excess carriers in the emission layer 15, the lifetime of the organic light-emitting diode 100 is reduced.

In particular, the lifetime of the organic light-emitting diode 100 is more prone to becoming shorter when electrons become excess carriers than when holes become excess carriers. The lifetime of the organic light-emitting diode 100 of the second embodiment can be increased by making the film thickness of the electron transport region 80 greater than the film thickness of the hole transport region 70.

In the organic light-emitting diode 100 of the second embodiment, the film thickness of the hole transport region 70 is less than the film thickness of the electron transport region 80. Here, the film thicknesses of the hole transport region 70 and the electron transport region 80 are preferably designed in consideration of the mobility of holes in the hole transport region 70 and the mobility of electrons in the electron transport region 80. Generally, the electron mobility of a material with an electron transporting property is greater than the hole mobility of a material with a hole transporting property, and therefore the mobility of electrons in the electron transport region 80 is greater than the mobility of holes in the hole transport region 70. In order to realize a balance between electrons and holes in the emission layer 15, the film thickness of the hole transport region 70 may be relatively less than the film thickness of the electron transport region 80.

In the first embodiment, since the mobility of holes is generally less than the mobility of electrons, in order to adjust the mobility in the hole transport region 70, there are cases where a P-type dopant is implanted in the hole transport region 70. The hole transport region 70 of the second embodiment has a smaller film thickness than the electron transport region 80, and therefore there is no need to implant the P-type dopant. In this way, it is possible to simplify the manufacturing process of the organic light-emitting diode 100 of the second embodiment.

Furthermore, the semi-crystalized organic layer 86 of the first embodiment and the second embodiment is provided on the cathode 30 side of the emission layer 15. By providing the semi-crystalized organic layer 86 on the cathode 30 side of the emission layer 15, it is possible to extract the plasmon loss Mp and the other propagation modes (e.g. the propagation mode M2 and the propagation mode M3) on the cathode 30 side as the external mode M1’. In this way, the organic light-emitting diode 100 reduces the plasmon loss on the cathode 30 side and makes it easier to improve the EQE.

For example, the organic light-emitting diode 100 of the second embodiment has, on 10 nm of ITO forming the anode 20, the hole injection layer 72 with a film thickness of 7 nm, the hole transport layer 74 with a film thickness of 25 nm, the electron barrier layer 76 with a film thickness of 7 nm, the emission layer 15 with a film thickness of 30 nm, the hole barrier layer 82 and electron transport layer 84 with a total film thickness of 103 nm, the semi-crystalized organic layer 86 with a film thickness of 10 nm, the electron injection layer 88 with a film thickness of 1.0 nm, and the cathode 30 with a film thickness of 11 nm. It should be noted that the film thickness of each layer is an example, and is not limited to the above. The film thicknesses of each of the hole barrier layer 82, the electron transport layer 84, and the semi-crystalized organic layer 86 may be suitably adjusted in consideration of the element characteristics such that the total optical thickness becomes equal, and are not particularly limited. The semi-crystalized organic layer 86 of the second embodiment may have the function of the electron injection layer 88. If the semi-crystalized organic layer 86 has the function of the electron injection layer 88, the electron injection layer 88 is unnecessary.

Fig. 2C shows an exemplary configuration of the organic light-emitting diode 100 according to a third embodiment. The organic light-emitting diode 100 of the third embodiment differs from the organic light-emitting diode 100 of the first embodiment in that the semi-crystalized organic layer 86 is provided in the hole transport region 70. In other words, the cathode 30 and the anode 20 of the third embodiment are respectively examples of a second electrode and a first electrode. In the description of the third embodiment, focus is placed on points that are different from the first embodiment.

The semi-crystalized organic layer 86 is provided between the anode 20 and the hole injection layer 72. However, the semi-crystalized organic layer 86 may be provided between the hole injection layer 72 and the hole transport layer 74. The semi-crystalized organic layer 86 of the third embodiment is provided in contact with the anode 20. Furthermore, the semi-crystalized organic layer 86 may have the function of the hole injection layer 72. If the semi-crystalized organic layer 86 has the function of the hole injection layer 72, the hole injection layer 72 is unnecessary. The semi-crystalized organic layer 86 extracts the plasmon loss between the organic layer 10 and the anode 20 as the external mode. Furthermore, even when the semi-crystalized organic layer 86 is provided in the hole transport region 70, the emission light is scattered by the semi-crystals of the semi-crystalized organic layer 86 and is easily extracted as the external mode. The optical conditions of the organic light-emitting diode 100 may be calculated using the same method as in the first embodiment.

Fig. 2D shows an exemplary configuration of the organic light-emitting diode 100 according to a fourth embodiment. The organic light-emitting diode 100 of the fourth embodiment differs from the organic light-emitting diode 100 of the third embodiment in that the film thickness of the electron transport region 80 is greater than the film thickness of the hole transport region 70. In the description of the fourth embodiment, focus is placed on points that are different from the third embodiment. The cathode 30 and the anode 20 of the fourth embodiment are respectively examples of a second electrode and a first electrode.

The semi-crystalized organic layer 86 is provided between the anode 20 and the hole injection layer 72, within the hole transport region 70. The semi-crystalized organic layer 86 of the fourth embodiment is provided in contact with the anode 20. It should be noted that the semi-crystalized organic layer 86 may have the function of the hole injection layer 72. If the semi-crystalized organic layer 86 has the function of the hole injection layer 72, the hole injection layer 72 is unnecessary. Even when the film thickness of the hole transport region 70 is less than the film thickness of the electron transport region 80, as in the fourth embodiment, the semi-crystalized organic layer 86 may be provided in the hole transport region 70. The optical conditions of the organic light-emitting diode 100 may be calculated using the same method as in the first embodiment.

In the third embodiment, since the mobility of holes is generally less than the mobility of electrons, there are cases where a P-type dopant is implanted in the hole transport region 70 in order to adjust the mobility of the hole transport region 70. The hole transport region 70 of the fourth embodiment has a smaller film thickness than the electron transport region 80, and therefore there is no need to implant the P-type impurities. In this way, it is possible to simplify the manufacturing process of the organic light-emitting diode 100 of the fourth embodiment.

Fig. 2E shows an exemplary configuration of the organic light-emitting diode 100 according to a fifth embodiment. The organic light-emitting diode 100 of the fifth embodiment differs from the organic light-emitting diode 100 of the first embodiment in that the semi-crystalized organic layer 86 is provided both between the emission layer 15 and the anode 20 and between the emission layer 15 and the cathode 30. In the fifth embodiment, the semi-crystalized organic layer 86a is provided between the emission layer 15 and the anode 20. The semi-crystalized organic layer 86b is provided between the emission layer 15 and the cathode 30.

With each film thickness as an optical condition in the design of elements and the light extraction efficiency as an interference condition, each film thickness is determined according to the element design regarding the positional relationship of the respective films to include at least two locations where the light extraction efficiency becomes large. Accordingly, the film thickness of the electron transport region 80 may be smaller or larger than the film thickness of the hole transport region 70.

Fig. 3 shows exemplary light propagation modes in the organic light-emitting diode 100. Fig. 3 shows propagation modes M1 to M3 and the plasmon loss Mp.

The propagation mode M1 shows an example of the external mode. The propagation mode M1 is a propagation mode in which the emission light generated by the organic layer 10 is radiated to the outside of the organic light-emitting diode 100.

The propagation mode M2 shows an example of the substrate mode. The propagation mode M2 is a mode in which light is propagated between the surface of the sealing substrate 60 and the surface of the anode 20. For example, in the propagation mode M2, the emission light generated by the organic layer 10 is reflected at the surface of the sealing substrate 60. Furthermore, in the propagation mode M2, the light reflected at the surface of the sealing substrate 60 may be reflected at the surface of the anode 20.

The propagation mode M3 shows an example of the waveguide mode. The propagation mode M3 is a mode in which the emission light generated by the organic layer 10 is propagated within an arbitrary layer by being trapped within this layer. For example, in the propagation mode M3, the emission light generated by the organic layer 10 is propagated within the encapsulation layer 40. Furthermore, the emission light generated by the organic layer 10 is propagated within the organic layer 10.

The plasmon loss Mp is a mode in which LSPR (Localized Surface Plasmon Resonance) occurs at the surfaces of the organic layer 10. Furthermore, in the plasmon loss Mp, energy diffusion due to the plasmon loss occurs at the interface between the organic layer 10 and the anode 20 and at the interface between the organic layer 10 and the cathode 30.

Here, a method considered to increase the EQE of the organic light-emitting diode 100 is to increase the internal quantum efficiency (IQE) in the organic layer 10 and also improve the light extraction efficiency of the light emitted from the emission layer 15 to the outside.

Here, the EQE η _φext is shown by the following expression.

η _φext = η _ext × η _φint

η _ext is the light extraction efficiency. Furthermore, the IQE η _φint is shown by the following expression.

η _φint = γ×η _r×η _φf

γ is the balance factor. η _r is the recombination factor between the holes and electrons. η _f is the emission efficiency of the emission layer 15 including the organic layer 10 described further below.

In other words, in order to improve the emission efficiency, it is enough to improve the four factors that constitute the EQE η _φext. It should be noted that the light extraction efficiency η _ext is approximately 20%to 25%, and almost all of the emission light propagates within the elements, thereby changing into heat and becoming inactive. In particular, there are simulation results showing that about 50%of the emission light from the emission layer 15 is lost as plasmon loss. The organic light-emitting diode 100 of the embodiment is provided with the semi-crystalized organic layer 86 and extracts the emission light of the plasmon loss Mp and other propagation modes (e.g. the propagation mode M2 and the propagation mode M3) as the external mode M1’, and can thereby improve the EQE η _φext.

Fig. 4 is a schematic view of the layered structure of the organic light-emitting diode 100. In the layered structure, the organic layer 10 having an organic layer 95 and the semi-crystalized organic layer 86 is provided above a glass substrate 90. Fig. 4 shows that the interface between the cathode 30 and the organic layer 10 has an unevenness corresponding to the semi-crystalized organic layer 86, as a result of the organic light-emitting diode 100 including the semi-crystalized organic layer 86.

Due to the unevenness of the semi-crystalized organic layer 86, the direction of the energy vector of the plasmon loss is changed, the plasmon loss is recombined as light, and the light can be extracted as the external mode. Furthermore, by scattering the emission light of the organic layer 10, the semi-crystalized organic layer 86 can also extract this light as the external mode. In this way, the quantum efficiency of the organic light-emitting diode 100 is improved.

Fig. 5A to Fig. 5F show examples of observation results of the morphology of the semi-crystalized organic layer 86. In Fig. 5A to Fig. 5F, cases in which the particle diameter of the semi-crystalized organic layer 86 is changed are disclosed. For example, the particle diameter of the semi-crystalized organic layer 86 can be obtained by measuring the unevenness of the surface of the semi-crystalized organic layer 86 using a measurement device such as an AFM (Atomic Force Microscope) . Since the semi-crystalized organic layer 86 does not have a uniform particle diameter, the particle diameter of the semi-crystalized organic layer 86 may be determined by taking the average of a plurality of particle diameters. The scale bars in Fig. 5A to Fig. 5F show the maximum values and minimum values of the height difference of the semi-crystalized organic layer 86.

Fig. 6A shows an exemplary configuration of an organic layer 510 according to a comparative example. The organic layer 510 of the comparative example includes an emission layer (EML) 515, a hole transport region 570, and an electron transport region 580. The organic layer 510 of the comparative example differs from the organic layer 10 according to the first embodiment by not including the semi-crystalized organic layer 86.

The hole transport region 570 includes a hole injection layer (HIL) 572, a hole transport layer (HTL) 574, and an electron barrier layer (EBL) 576. The electron transport region 580 includes a hole barrier layer (HBL) 582, an electron transport layer (ETL) 584, and an electron injection layer (EIL) 588. The hole transport region 570 of the comparative example does not include the semi-crystalized organic layer between the electron transport layer 584 and the electron injection layer 588.

Fig. 6B shows examples of light propagation modes in the organic light-emitting diode 500. The organic light-emitting diode 500 of the comparative example does not include the semi-crystalized organic layer, and therefore cannot extract the plasmon loss Mp and other propagation modes (e.g. the propagation mode M2 and the propagation mode M3) as the external mode M1’. Therefore, the energy of the plasmon loss Mp is not emitted as light and dissipates, resulting in loss, and the EQE η _φext of the organic light-emitting diode 500 cannot be improved.

Fig. 7 is a contribution rate of the power reduction result for each of red, green, and blue. The vertical axis indicates the OLED power reduction amount, and the horizontal axis indicates the improvement ratio of the EQE for red, green, and blue. It is understood that blue has a higher power reduction effect in the organic light-emitting diode 100 than red and green. In particular, in the case of blue, the effect of the panel power reduction is almost double. In particular, the organic light-emitting diode 100 can improve the EQE for blue, which greatly contributes to the panel power consumption, and therefore the effect of reducing the power consumption is large. The spectrum of Fig. 7 is data in a case where the viewing angle of the organic light-emitting diode 100 is 0°.

Fig. 8 shows an exemplary EL spectrum of the organic light-emitting diode 100. The vertical axis indicates the intensity (a.u. ) of the light radiated from the organic light-emitting diode 100, and the horizontal axis indicates the wavelength (μm) . The solid line indicates the spectrum of the organic light-emitting diode 100 according to the embodiment. The broken line indicates the spectrum of the organic light-emitting diode 500 of the comparative example. From Fig. 8, it is understood that the emission light intensity of the organic light-emitting diode 100 is improved more than that of the organic light-emitting diode 500. For example, the improvement was 88%at a viewing angle of 30°, 56%at a viewing angle of 45°, and 29%at a viewing angle of 60°. Furthermore, the improvement was 10%at a viewing angle of 0°.

Fig. 9A to Fig. 9D show examples of viewing angle properties of the organic light-emitting diode 100. In Fig. 9A to Fig. 9D, the emission efficiency is shown in cases where the structure of the organic light-emitting diode 100 is changed. The vertical axis indicates the emission efficiency Z/J, and the horizontal axis indicates the viewing angle (°) of the organic light-emitting diode 100. The emission efficiency Z/J is a value obtained by standardizing Z with the current density J. Z is a value indicating the blue color component. The solid line indicates the viewing characteristic of the organic light-emitting diode 100 according to the embodiment that includes the semi-crystalized organic layer 86. The broken line indicates the viewing characteristic of the organic light-emitting diode 500 according to the comparative example, which does not include the semi-crystalized organic layer 86. Fig. 9A and Fig. 9D each show the emission efficiency at the front surface of the organic light-emitting diode 100. It is understood that the viewing characteristic of the organic light-emitting diode 100 is improved more than that of the organic light-emitting diode 500.

Fig. 9A is a case using a structure in which the film thickness D70 of the hole transport region 70 is greater than the film thickness D80 of the electron transport region 80 (i.e. D70 > D80) . Furthermore, Fig. 9A shows a case in which the cathode 30 is a strong cavity. A strong cavity is a case where MgAg, which is a material of the cathode 30, is formed with a ratio of Mg: Ag = 9: 1 and the film thickness is 11 nm. On the other hand, a weak cavity is a case where MgAg, which is a material of the cathode 30, is formed with a ratio of Mg: Ag = 2: 1 and the film thickness is 11 nm. In other words, the composition of the cathode 30 differs between the strong cavity and the weak cavity. In the case of the strong cavity, light is easily focused on the front surface. In the case of the weak cavity, the light focused on the front surface is weaker than in the case of the strong cavity, but the emission light distribution is closer to lambertian.

Fig. 9B is a case using a structure in which the film thickness D70 of the hole transport region 70 is greater than the film thickness D80 of the electron transport region 80 (i.e. D70 > D80) . Furthermore, Fig. 9B shows a case in which the cathode 30 is a weak cavity.

Fig. 9C is a case using a structure in which the film thickness D80 of the electron transport region 80 is greater than the film thickness D70 of the hole transport region 70 (i.e. D80 >D70) . Furthermore, Fig. 9C shows a case in which the cathode 30 is a strong cavity.

Fig. 9D is a case using a structure in which the film thickness D80 of the electron transport region 80 is greater than the film thickness D70 of the hole transport region 70 (i.e. D80 >D70) . Furthermore, Fig. 9D shows a case in which the cathode 30 is a weak cavity.

Fig. 9E is a table showing average values of the viewing angle properties of the organic light-emitting diode 100. Fig. 9A to Fig. 9D show viewing angle properties of certain specific samples, and Fig. 9E shows the average value of a number N = 10 of samples. In this way, in Fig. 9E, it is possible to accurately know the trends of the characteristics when the conditions of the organic light-emitting diode 100 are changed.

The efficiency improvement ratio indicates the improvement ratio of the emission efficiency in a case where the semi-crystalized organic layer 86 is provided. Regardless of the relationship between the film thickness of the hole transport region 70 and the film thickness of the electron transport region 80, an efficiency improvement ratio of approximately 10%at the front position was achieved. Furthermore, regardless of whether the strong cavity or weak cavity was used, an efficiency improvement ratio of approximately 10%at the front position was achieved.

By providing the organic light-emitting diode 100 with the semi-crystalized organic layer 86, it is possible to improve the luminance. Therefore, even if the film thickness of the electron transport region 80 is greater than the film thickness of the hole transport region 70, it is possible to restrict the drop in luminance of the front surface and to improve the viewing angle property. Furthermore, by making the film thickness of the electron transport region 80 greater than the film thickness of the hole transport region 70, electrons that are excess carriers are less likely to occur and the lifetime of the organic light-emitting diode 100 is increased. In this way, by providing the semi-crystalized organic layer 86 and also making the film thickness of the electron transport region 80 greater than the film thickness of the hole transport region 70 in the organic light-emitting diode 100, it is possible to increase the lifetime while improving both the emission efficiency and the viewing angle property of the front surface.

Fig. 10A shows change over time of the luminance of the organic light-emitting diode 100. The vertical axis indicates the luminance value, and the horizontal axis indicates time (hours) . The solid line indicates the change over time of the luminance of the organic light-emitting diode 100 according to the embodiment. The broken line indicates the change over time of the luminance of the organic light-emitting diode 500 according to the comparative example. The organic light-emitting diode 100 of the embodiment maintains a greater luminance than the organic light-emitting diode 500, even after 300 hours have passed.

Fig. 10B shows the change over time of the applied voltage of the organic light-emitting diode 100. The vertical axis indicates the applied voltage (V) , and the horizontal axis indicates time (hours) . The solid line indicates the change over time of the luminance of the organic light-emitting diode 100 according to the embodiment. The broken line indicates the change over time of the luminance of the organic light-emitting diode 500 according to the comparative example. The organic light-emitting diode 100 of the embodiment maintains a greater luminance than the organic light-emitting diode 500, even after 300 hours have passed.

As shown above, by using the semi-crystalized organic layer 86 in the organic light-emitting diode 100, it is possible to improve the viewing angle property, improve the EQE of blue light, and increase the lifetime.

If the organic light-emitting diode 100 is a display apparatus for displaying information, the organic light-emitting diode 100 can be applied to any apparatus.

Examples of electronic devices adopting a display apparatus that includes the organic light-emitting diode 100 include a television apparatus, a monitor for a computer or the like, a digital camera, a digital video camera, a digital photo frame, a portable telephone, a portable game device, a goggle-type display, a portable information terminal, an audio playback apparatus, a large-scale game device such as a pachinko machine, and the like. Specific examples of these electronic devices are shown in Fig. 11A to Fig. 11F, respectively.

Fig. 11A shows an exemplary case in which the organic light-emitting diode 100 is adopted in a portable terminal 200 such as a smartphone. The portable terminal 200 includes a chassis 202 and a display section 204. The display section 204 is provided in the chassis 202. The display section 204 includes the organic light-emitting diode 100, and displays prescribed information. By adopting the organic light-emitting diode 100 in the display section 204, the portable terminal 200 can realize display with an excellent viewing angle property.

Fig. 11B shows an exemplary case in which the organic light-emitting diode 100 is adopted in a portable terminal 210 such as a smartphone. The portable terminal 210 includes a chassis 212 and a display section 214. In the chassis 212, the main surface on which the display section 214 is provided is a curved surface. By forming the organic light-emitting diode 100 on a flexible substrate, the display section 214 can be adopted in a chassis 212 having a curved surface.

Fig. 11C shows an exemplary case in which the organic light-emitting diode 100 is adopted in a folding-type portable terminal 220. The portable terminal 220 includes a chassis 222 and a display section 224. The chassis 222 has a mechanism that enables folding. The display section 224 includes three

display sections

224a, 224b, and 224c, and can be folded in response to a folding movement of the chassis 222. The portable terminal 220 can realize display with high luminance and a wide viewing angle, and can also improve portability.

Fig. 11D shows an exemplary case in which the organic light-emitting diode 100 is adopted in a notebook computer 230. The notebook computer 230 includes a chassis 232 and a display section 234. By adopting the organic light-emitting diode 100 in the display section 234, the notebook computer 230 can realize display with high luminance and a wide viewing angle.

Fig. 11E shows an exemplary case in which the organic light-emitting diode 100 is adopted in a television apparatus 240. The television apparatus 240 includes a chassis 242 and a display section 244. By adopting the organic light-emitting diode 100 in the display section 244, the television apparatus 240 can realize display with high luminance and a wide viewing angle.

Fig. 11F shows an exemplary case in which the organic light-emitting diode 100 is adopted in smart glasses 250. The smart glasses 250 include a chassis 252 and a display section 254. The organic light-emitting diode 100 can be provided on a curved surface, and therefore the display section 254 can be provided along the glass of the smart glasses 250.

Fig. 11G shows an exemplary case in which the organic light-emitting diode 100 is adopted in a smart watch 260. The smart watch 260 includes a chassis 262 and a display section 264. By adopting the high-luminance organic light-emitting diode 100 in the display section 264, the smart watch 260 can improve the outdoor visibility. In the chassis 262, the main surface on which the display section 264 is provided is a flat surface, but may be a curved surface instead.

The material of the semi-crystalized organic layer 86 may include an electron transporting material. Materials offered as examples of the material of the semi-crystalized organic layer 86 may be used as the material of the electron transport layer 84. For example, the material of the semi-crystalized organic layer 86 includes 8-hydroxyquinoline aluminum (Alq ₃) . Alq ₃ is shown in the following formula.

Formula 1:

Furthermore, the material of the semi-crystalized organic layer 86 may contain the dibenzimidazole derivative shown in Formula 2 below.

Formula 2:

It should be noted that Y ₁ to Y ₈ in Formula 2 each represent an aryl group having 6 to 60 carbon atoms that may have a substituent, an alkenyl group that may have a substituent, a pyridyl group that may have a substituent, a quinolyl group that may have a substituent, an alkoxy group having 1 to 20 carbon atoms that may have a substituent, an alkyl group having 1 to 20 carbon atoms that may have a substituent, or an aliphatic cyclic group that may have a substituent. Y ₇ and Y ₈ may form a ring via a linking group.

Furthermore, specific examples of dibenzimidazole derivatives are shown in the following formulas.

Formula 3:

Formula 4:

Formula 5:

The material of the semi-crystalized organic layer 86 may contain a dibenzimidazole derivative. Here, a dibenzimidazole derivative is a derivative using dibenzimidazole as the mother skeleton. For example, a dibenzimidazole derivative is a material shown by Formulas 6 to 8 below, with a strong electron injection property. The material of the semi-crystalized organic layer 86 may be a mixed layer that includes another compound when a dibenzimidazole derivative is included. The other compound may be at least one type of compound selected from among alkali metals, alkaline earth metals, rare earth metals and oxides thereof, complex oxides, fluorides, and carbonates.

Formula 6:

Formula 7:

Formula 8:

The material of the semi-crystalized organic layer 86 may be a compound that includes alkyl-substituted thiazolyl or alkyl-substituted oxazolyl, as shown in Formula 9 below.

Formula 9:

In this formula, G is an m-valent group derived from one compound selected from the group consisting of an aromatic hydrocarbon compound having 6 to 40 carbon atoms and a heteroaromatic compound having 4 to 40 carbon atoms, or an m-valent group derived from a compound obtained by linking two compounds selected from the same group with a single bond. One of the hydrogen atoms in these groups may be replaced with alkyl having 1 to 12 carbon atoms, cycloalkyl having 3 to 12 carbon atoms, or aryl having 6 to 24 carbon atoms.

X ¹ to X ⁶ are independently =CR ¹-or =N-, at least two among X ¹ to X ⁶ are =CR ¹-, R ¹ in two =CR ¹-units among X ¹ to X ⁶ is a bond that bonds with G or an azole ring, and R ₁ in each other =CR ¹-is hydrogen or alkyl having 1 to 4 carbon atoms.

If R ² and R ³, which are substituents of the azole ring, are alkyl having 1 to 4 carbon atoms, the alkyl of R ² and the alkyl of R ³ may be the same, or may be different. The alkyl having 1 to 4 carbon atoms may be either straight-chain or branched-chain. In other words, the alkyl having 1 to 4 carbon atoms is straight-chain alkyl having 1 to 4 carbon atoms or branched-chain alkyl having 3 or 4 carbon atoms. Examples of this include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, phenyl, s-butyl, n-pentyl, isopentyl, neopentyl, t-butyl, and the like.

Y is independently -O-or -S-, R ² is independently alkyl having 1 to 4 carbon atoms, R ³ is independently hydrogen or alkyl having 1 to 4 carbon atoms, and m is an integer from 2 to 4. The groups formed by the azole ring and the 6-member ring may be the same or may be different. Any one hydrogen atom in each ring and alkyl in the formula may be replaced with deuterium.

The alkyl having 1 to 12 carbon atoms, in which any one hydrogen atom of an m-valent group derived from one compound selected from the group consisting of an aromatic hydrocarbon compound having 6 to 40 carbon atoms and a heteroaromatic compound having 4 to 40 carbon atoms and an m-valent group derived from a compound obtained by linking two compounds selected from the same group with a single bond may be replaced, is straight-chain alkyl having 1 to 12 carbon atoms or branched-chain alkyl having 3 to 12 carbon atoms. Furthermore, the alkyl having 1 to 12 carbon atoms may be alkyl having 1 to 6 carbon atoms (branched-chain alkyl having 3 to 6 carbon atoms) or may be alkyl having 1 to 4 carbon atoms (branched-chain alkyl having 3 to 4 carbon atoms) . Specific examples of this include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, phenyl, s-butyl, t-butyl, n-pentyl, isopentyl, neopentyl, naphthyl, t-pentyl, n-hexyl, 1-methylpentyl, 4-methyl-2-pentyl, 3, 3-dimethylbutyl, 2-ethylbutyl, and the like.

Specific examples of the alkyl having 3 to 12 carbon atoms, in which any one hydrogen atom of an m-valent group derived from one compound selected from the group consisting of an aromatic hydrocarbon compound having 6 to 40 carbon atoms and a heteroaromatic compound having 4 to 40 carbon atoms and an m-valent group derived from a compound obtained by linking two compounds selected from the same group with a single bond may be replaced, include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, methylcyclopentyl, cycloheptyl, methylcyclohexyl, cyclooctyl, dimethylcyclohexyl, and the like.

Specific examples of the alkyl having 6 to 24 carbon atoms, in which any one hydrogen atom of an m-valent group derived from one compound selected from the group consisting of an aromatic hydrocarbon compound having 6 to 40 carbon atoms and a heteroaromatic compound having 4 to 40 carbon atoms and an m-valent group derived from a compound obtained by linking two compounds selected from the same group with a single bond may be replaced, include phenyl which is monocyclic aryl, (o-, m-, p-) tolyl, mesityl (2, 4, 6-trimethylphenyl) , (2, 3-, 2, 4-, 2, 5-, 2, 6-, 3, 4-, 3, 5-) xylyl, (o-, m-, p-) cumenyl, (2-, 3-, 4-) biphenylyl which is a bicyclic aryl, (1-, 2-) naphthyl which is a fused bicyclic aryl, terphenylyl which is a tricyclic aryl (m-terphenyl-2'-yl, o-terphenyl-3'-yl, o-terphenyl-4'-yl, m-terphenyl-4'-yl m-terphenyl-5'-yl, p-terphenyl-2'-yl, o-terphenyl-2-yl, o-terphenyl-3-yl, o-terphenyl-4-yl, p-terphenyl-3-yl, p-terphenyl-4-yl) , p-terphenyl-2-yl, m-terphenyl-2-yl, m-terphenyl-3-yl, m-terphenyl-4-yl, anthracene- (1-, 2-, 9-) yl which is a fused tricyclic aryl, phenalene- (1-, 2-) yl, (1-, 2-, 3-, 4-, 9-) phenanthryl, acenaphthylene- (1-, 3-, 4-, 5-) yl, fluorene- (1-, 2-, 3-, 4-, 9-) yl, triphenylene- (1-, 2-) yl which is a fused tetracyclic aryl, pyrene- (1-, 2-, 4-) yl, tetracene- (1-, 2-, 5-) yl, perylene- (1-, 2-, 3-) yl which is a fused pentacyclic aryl, and the like.

G in Formula 9 may be one group selected from the set of groups shown in Formulas 10 to 12 below.

Formula 10:

Formula 11:

Formula 12:

Furthermore, the material of the semi-crystalized organic layer 86 may include a material shown in Formula 13 below.

Formula 13:

In this formula, Ar may be an m-valent group derived from an aromatic hydrocarbon having 6 to 40 carbon atoms or an m-valent group derived from an aromatic heterocyclic ring having 2 to 40 carbon atoms. Any one hydrogen atom in these groups may be replaced with alkyl having 1 to 4 carbon atoms. L is one group selected from the set of a single bond or divalent group. m is an integer from 1 to 4. When m is 2, 3, or 4, the groups formed by the pyridine ring and L may be the same or may be different.

Ar may be one group selected from the set of groups shown in Formulas 14 to 17 below.

Formula 14:

Formula 15:

Formula 16:

Formula 17:

In Formulas 14 to 17, Z is independently -O-, -S-, or one group selected from the set of divalent groups shown by (2) or (3) in Formula 18, and any one hydrogen atom in each group may be replaced with alkyl having 1 to 4 carbon atoms or aryl having 6 to 18 carbon atoms.

Formula 18:

In (2) , R ¹ is phenyl, biphenylyl, naphthyl, or terphenylyl, in (3) , R ² is independently phenyl or methyl, and R ² units may be bonded together to form a ring.

L is one group selected from the set of a single bond and the divalent groups shown in Formulas 19 and 20.

Formula 19:

In Formula 19, X ¹ to X ⁶ are independently =CR ¹-or =N-, at least two among X ¹ to X ⁶ are =CR ¹-, R ¹ in two =CR ¹-units among X ¹ to X ⁶ is a bond that bonds with Ar or a pyridine ring, and R ₁ in the other =CR ¹-units may be hydrogen.

Formula 20:

In Formula 20, X ⁷ to X ¹⁴ are independently =CR ¹-or =N-, at least two among X ⁷ to X ¹⁴ are =CR ¹-, R ¹ in two =CR ¹-units among X ⁷ to X ¹⁴ is a bond that bonds with Ar or a pyridine ring, and R ₁ in the other =CR ¹-units may be hydrogen.

Any one hydrogen atom in L may be replaced with alkyl having 1 to 4 carbon atoms or aryl having 6 to 18 carbon atoms. Any one hydrogen atom of the pyridine ring may be replaced with alkyl having 1 to 4 carbon atoms, phenyl, biphenylyl, or naphthyl. Any one hydrogen atom in each ring and alkyl in the formula may be replaced with deuterium.

Ar may be one group selected from the set of groups shown in Formulas 21 and 22 below.

Formula 21:

Formula 22:

Furthermore, the material of the semi-crystalized organic layer 86 may include a material shown in Formula 23 below.

Formula 23:

In the formula, Ar may be an m-valent group derived from an aromatic hydrocarbon having 6 to 50 carbon atoms or an m-valent group derived from an aromatic heterocyclic ring having 2 to 50 carbon atoms. Any one hydrogen atom of these groups may be replaced with alkyl having 1 to 6 carbon atoms, cycloalkyl having 3 to 6 carbon atoms, or aryl having 6 to 12 carbon atoms. m is an integer from 2 to 4. R ¹ may be alkyl having 1 to 4 carbon atoms. 2 to 4 pyridylphenyl groups may be the same, or may be different. Any hydrogen atom in each ring and alkyl may be replaced with deuterium.

Ar may be one group selected from among the set of groups shown in Formulas 24 and 25 below.

Formula 24:

Formula 25:

Z is independently -O-, -S-, or a divalent group shown by Formula 26, and any one hydrogen atom in each group may be replaced with alkyl having 1 to 6 carbon atoms, cycloalkyl having 3 to 6 carbon atoms, or aryl having 6 to 12 carbon atoms.

Formula 26:

In (2) , R ² is phenyl, naphthyl, biphenylyl or terphenylyl, in (3) , R ³ is independently methyl, biphenylyl, or phenyl, and two R ³ units may be linked to each other to form a ring.

Furthermore, the material of the semi-crystalized organic layer 86 may include the material shown by Formula 27 below.

Formula 27:

In the formula, Ar is an m-valent group derived from an aromatic hydrocarbon having 6 to 40 carbon atoms or an m-valent group derived from an aromatic heterocyclic ring having 2 to 40 carbon atoms. Hydrogen atoms in these groups may be replaced by alkyl having 1 to 12 carbon atoms or cycloalkyl having 3 to 12 carbon atoms. X ¹ to X ⁶ are independently =CR ¹-or =N-, at least two among X ¹ to X ⁶ are =CR ¹-, R ¹ in two =CR ¹-units among X ¹ to X ⁶ is a bond that bonds with Ar or an azole ring, and R ₁ in the other =CR ¹-units may be hydrogen or alkyl having 1 to 4 carbon atoms.

Y is independently -O-or -S-, and any one hydrogen atom of an azole ring may be replaced with alkyl having 1 to 4 carbon atoms, biphenylyl, phenyl, or naphthyl. m is an integer from 2 to 4, and the groups formed by the azole ring and the 6-member ring may be the same or may be different. Any one hydrogen atom in each ring and alkyl in the formula may be replaced with deuterium.

Ar may be one group selected from the set of groups shown by Formulas 28 and 29 below.

Formula 28:

Formula 29:

Z is independently -O-, -S-, or a divalent group shown by (2) or (3) in Formula 30, and any one hydrogen atom in each group may be replaced with alkyl having 1 to 12 carbon atoms, cycloalkyl having 3 to 12 carbon atoms, or aryl having 6 to 24 carbon atoms.

Formula 30:

In (2) , R ² may be phenyl, naphthyl, biphenylyl or terphenylyl. In (3) , R ³ may be independently methyl, biphenylyl, or phenyl. Two R ³ units may be linked to each other to form a ring.

Furthermore, the material of the semi-crystalized organic layer 86 may include the material shown by Formula 31 below.

Formula 31:

a, b, c, and d in the formula are independently 1 or 0, but a and b are not simultaneously 0. Py ¹ and Py ² are independently pyridyl or bipyridyl, and any hydrogen atom of the this pyridyl or bipyridyl may be replaced with alkyl having 1 to 6 carbon atoms, cycloalkyl having 3 to 6 carbon atoms, aryl having 6 to 14 carbon atoms, or heteroaryl having 2 to 12 carbon atoms. Ar ¹ is hydrogen or aryl having 6 to 20 carbon atoms when a is 0 and arylene having 6 to 20 carbon atoms when a is 1, Ar ² is hydrogen or aryl having 6 to 20 carbon atoms when b is 0 and arylene having 6 to 20 carbon atoms when b is 1, and any hydrogen atom of this aryl or arylene may be replaced with alkyl having 1 to 6 carbon atoms, cycloalkyl having 3 to 6 carbon atoms, or aryl having 6 to 14 carbon atoms.

A is aryl having 6 to 20 carbon atoms, and any hydrogen atom of this aryl may be replaced with alkyl having 1 to 6 carbon atoms, cycloalkyl having 3 to 6 carbon atoms, or aryl having 6 to 14 carbon atoms.

R ¹ to R ⁸ are independently hydrogen atoms, alkyl having 1 to 6 carbon atoms, cycloalkyl having 3 to 6 carbon atoms, aryl having 6 to 14 carbon atoms, or heteroaryl having 2 to 10 carbon atoms, and any hydrogen atom of the aryl or heteroaryl may be replaced with alkyl having 1 to 6 carbon atoms or cycloalkyl having 3 to 6 carbon atoms. Any one hydrogen atom in this compound may be replaced with deuterium.

Py ¹ and Py ² may independently be one group selected from the set of groups shown by Formulas 32 and 33 below.

Formula 32:

Formula 33:

Formula 34:

Any hydrogen atom in these groups may be replaced with methyl, ethyl, isopropyl, n-propyl, s-butyl, t-butyl, n-butyl, n-pentyl, isopentyl, neopentyl, cyclohexyl, t-pentyl, n-hexyl, phenyl, biphenylyl, naphthyl, or pyridyl. Ar ¹ and Ar ² are independently phenylene, naphthalenediyl, anthracenediyl, or chrysendiyl, and any hydrogen atom in these groups may be replaced with methyl, ethyl, isopropyl, n-propyl, s-butyl, t-butyl, t-pentyl, n-hexyl, cyclohexyl, phenyl, biphenylyl, or naphthyl. A is phenyl, biphenylyl, naphthyl, or phenanthryl, and any hydrogen atom in these groups may be replaced with methyl, ethyl, isopropyl, n-propyl, s-butyl, t-butyl, t-pentyl, n-hexyl, cyclohexyl, phenyl, biphenylyl, or naphthyl. R ¹ to R ⁸ may independently be hydrogen atoms, methyl, ethyl, isopropyl, n-propyl, s-butyl, t-butyl, t-pentyl, n-hexyl, cyclohexyl, or phenyl. Additionally, c and d may independently be 1 or 0.

The material of the semi-crystalized organic layer 86 may include a material shown by Formula 35 below.

Formula 35:

Py in the formula is pyridyl, and any hydrogen atom of this pyridyl may be replaced with alkyl having 1 to 6 carbon atoms, cycloalkyl having 3 to 6 carbon atoms, or phenyl or biphenylyl in which alkyl having 1 to 6 carbon atoms or cycloalkyl having 3 to 6 carbon atoms may be substituted.

Bp is biphenylylene, and any hydrogen atom of this biphenylylene may be replaced with alkyl having 1 to 6 carbon atoms, cycloalkyl having 3 to 6 carbon atoms, or phenyl or biphenylyl in which alkyl having 1 to 6 carbon atoms or cycloalkyl having 3 to 6 carbon atoms may be substituted.

R is hydrogen, alkyl having 1 to 6 carbon atoms, cycloalkyl having 3 to 6 carbon atoms, or aryl having 6 to 14 carbon atoms, and any hydrogen atom of this aryl may be replaced with alkyl having 1 to 6 carbon atoms or cycloalkyl having 3 to 6 carbon atoms. Any one hydrogen atom in this compound may be replaced with deuterium.

Py is one group selected from the set of groups shown by Formulas 36 and 37 below. Bp is one group selected from the set of groups shown by Formula 38 below. Any hydrogen atom in this biphenylylene may be replaced with alkyl having 1 to 6 carbon atoms, cycloalkyl having 3 to 6 carbon atoms, or phenyl or biphenylyl in which alkyl having 1 to 6 carbon atoms cycloalkyl having 3 to 6 carbon atoms may be substituted. R is hydrogen, alkyl having 1 to 6 carbon atoms, cycloalkyl having 3 to 6 carbon atoms, or aryl having 6 to 14 carbon atoms, and any hydrogen atom in this aryl may be replaced with alkyl having 1 to 6 carbon atoms or cycloalkyl having 3 to 6 carbon atoms.

Formula 36:

Formula 37:

Formula 38:

Furthermore, the material of the semi-crystalized organic layer 86 may include a material shown by Formula 39 below.

Formula 39:

In the formula, Ar is aryl having 6 to 30 carbon atoms. In the formula, any hydrogen atom of Ar, a benzene ring, and a pyridine ring may be replaced with alkyl having 1 to 6 carbon atoms or cycloalkyl having 3 to 6 carbon atoms. Any one hydrogen atom in this compound may be replaced with deuterium.

Ar may be one group selected from the set of monovalent groups shown in Formulas 40 and 41.

Formula 40:

Formula 41:

Furthermore, the material of the semi-crystalized organic layer 86 may include a material shown by Formula 42 below.

Formula 42:

In the formula, Py may independently be a group shown by Formulas 43 to 46 below.

Formula 43:

Formula 44:

Formula 45:

Formula 46:

A -H unit of an anthracene ring, a naphthalene ring, a pyridine ring, and a benzene ring may be independently replaced with deuterium, alkyl having 1 to 6 carbon atoms, or cycloalkyl having 3 to 6 carbon atoms.

Furthermore, the material of the semi-crystalized organic layer 86 may include a material shown by Formula 47 below.

Formula 47:

In the formula, Ar is aryl having 6 to 30 carbon atoms. Py may be 2-pyridyl, 3-pyridyl, or 4-pyridyl. In the formula, any hydrogen atom of Ar, a benzene ring, and a pyridine ring may be replaced with alkyl having 1 to 6 carbon atoms or cycloalkyl having 3 to 6 carbon atoms. Any one hydrogen atom in this compound may be replaced with deuterium.

Ar is one group selected from the set of monovalent groups shown below.

Formula 48:

In the above formula, R ¹ is independently alkyl having 1 to 6 carbon atoms or phenyl, and any carbon atom in each group may be replaced with alkyl having 1 to 6 carbon atoms or cycloalkyl having 3 to 6 carbon atoms.

Furthermore, the material of the semi-crystalized organic layer 86 may include a material shown by Formula 49 below.

Formula 49:

In the formula, Py is pyridyl, and any hydrogen of this pyridyl may be replaced with alkyl having 1 to 6 carbon atoms, 1-naphthyl in which alkyl having 1 to 6 carbon atoms or cycloalkyl having 3 to 6 carbon atoms may be substituted, phenyl in which alkyl having 1 to 6 carbon atoms or cycloalkyl having 3 to 6 carbon atoms may be substituted, cycloalkyl having 3 to 6 carbon atoms, or 2-naphthyl in which alkyl having 1 to 6 carbon atoms or cycloalkyl having 3 to 6 carbon atoms may be substituted. R is hydrogen, alkyl having 1 to 6 carbon atoms, cycloalkyl having 3 to 6 carbon atoms, or aryl having 6 to 14 carbon atoms, and any hydrogen atom of this aryl may be replaced with alkyl having 1 to 6 carbon atoms or cycloalkyl having 3 to 6 carbon atoms. Furthermore, any one hydrogen atom in this compound may be replaced with deuterium.

Py may be a group selected from the set of monovalent groups shown below.

Formula 50:

Furthermore, the material of the semi-crystalized organic layer 86 may include a material shown by Formula 51 below.

Formula 51:

In the formula, Py is independently a group shown by Formulas 52 to 54 below.

Formula 52:

Formula 53:

Formula 54:

m and n are 0 or 1, but m+n = 1. At least one hydrogen atom in a benzene ring, a naphthalene ring, and a pyridine ring is replaced with an alkyl group having 1 to 6 carbon atoms or a cycloalkyl group having 3 to 6 carbon atoms.

Furthermore, the material of the semi-crystalized organic layer 86 may include a material shown by Formula 55 below.

Formula 55:

In the formula, Py is one group selected from the monovalent groups shown by Formulas 56 to 59 below, and any hydrogen atom of these groups may be replaced with an alkyl group having 1 to 6 carbon atoms or a cycloalkyl group having 3 to 6 carbon atoms.

Formula 56:

Formula 57:

Formula 58:

Formula 59:

Ar ¹ may be naphthalene-1, 4-diyl or naphthalene-1, 5-diyl. Any hydrogen atom in these groups may be replaced with an alkyl group having 1 to 6 carbon atoms or a cycloalkyl group having 3 to 6 carbon atoms.

Ar ² is phenyl or 2-naphthyl, and any hydrogen atom in these groups may be replaced with an alkyl group having 1 to 6 carbon atoms or a cycloalkyl group having 3 to 6 carbon atoms.

Py is one group selected from the monovalent groups shown below.

Formula 60:

Furthermore, the material of the semi-crystalized organic layer 86 may include a material shown by Formula 61 below.

Formula 61:

In the formula, Py is independently a group shown by Formulas 62 to 65.

Formula 62:

Formula 63:

Formula 64:

Formula 65:

m and n are 0 or 1, but m+n = 1. A -H unit in a benzene ring, a naphthalene ring, and a pyridine ring in the formula may be independently replaced with an alkyl group having 1 to 6 carbon atoms or a cycloalkyl group having 3 to 6 carbon atoms.

Furthermore, the material of the semi-crystalized organic layer 86 may include a material shown by Formula 66 below.

Formula 66:

In the formula, G is an n-valence linking group, and n is an integer from 2 to 4. R ¹ to R ⁴ are independently hydrogen atoms, monovalent groups, or free valence groups that link with G, R ⁵ to R ⁸ are independently hydrogen or monovalent groups, and one of R ¹ to R ⁴ is a free valence group that links with G. Furthermore, n 3, 4’-bipyridyl groups may be the same or may be different.

Furthermore, the material of the semi-crystalized organic layer 86 may include a material shown by Formula 67 below.

Formula 67:

In the formula, G is an n-valence linking group, and n is an integer from 2 to 4. R ¹ to R ⁴ may independently be hydrogen atoms, monovalent groups, or free valence groups that link with G. R ⁵ to R ⁸ are independently hydrogen atoms or monovalent groups, and one of R ¹ to R ⁴ is a free valence group that links with G. Furthermore, n 4, 4’-bipyridyl groups may be the same or may be different.

One of R ¹ to R ⁴ is a free valence group that links with G while the others are hydrogen atoms, and R ⁵ to R ⁸ may be hydrogen atoms.

This compound may be shown by the following formula.

Formula 68:

In the formula, G may be one group selected from the set of linking groups shown by (G1) to (G3) below. One of R ⁹ to R ¹² is a free valence group that links with G while the others are hydrogen atoms, and one of R ¹³ to R ¹⁶ is a free valence group that links with G while the others are hydrogen atoms.

Formula 69:

——G ¹—— (G1)

——G ¹——G ¹—— (G2)

——G ¹——G ¹——G ¹—— (G3)

In the formula, G ¹ may independently be a second valence group derived from one compound selected from the set of compounds shown by Formulas 70 to 73 below.

Formula 70:

Formula 71:

Formula 72:

Formula 73:

Furthermore, the material of the semi-crystalized organic layer 86 may include a material shown by Formula 74 below.

Formula 74:

In the formula, G is an n-valence linking group, and n is an integer from 2 to 4. R ¹ to R ⁴ are independently hydrogen atoms, monovalent groups, or free valence groups that link with G, R ⁵ to R ⁸ are independently hydrogen atoms or monovalent groups, and one of R ¹ to R ⁴ is a free valence group that links with G. Furthermore, n 2, 4’-bipyridyl groups may be the same or may be different.

Furthermore, the material of the semi-crystalized organic layer 86 may include a material shown by Formula 75 below.

Formula 75:

In the formula, G is an n-valence linking group, and n is an integer from 2 to 4. R ¹ to R ⁴ may independently be hydrogen atoms, monovalent groups, or free valence groups that link with G. R ⁵ to R ⁸ are independently hydrogen atoms or monovalent groups, and one of R ¹ to R ⁴ is a free valence group that links with G. Furthermore, n 2, 3’-bipyridyl groups may be the same or may be different.

This compound may be a material shown below.

Formula 76:

In the formula, G may be one group selected from the set of groups shown by (G1) to (G3) below. One of R ⁹ to R ¹² is a free valence group that links with G while the others are hydrogen atoms. One of R ¹³ to R ¹⁶ is a free valence group that links with G while the others are hydrogen atoms.

Formula 77:

——G ¹—— (G1)

——G ¹——G ¹—— (G2)

——G ¹——G ¹——G ¹—— (G3)

In the formula, G ¹ may independently be a second valence group derived from one compound selected from the set of compounds shown by Formulas 78 to 81 below.

Formula 78:

Formula 79:

Formula 80:

Formula 81:

Furthermore, the material of the semi-crystalized organic layer 86 may include a material shown by Formula 82 below.

Formula 82:

In the formula, R ¹ to R ⁴ are each independently a hydrogen atom, a substituted or unsubstituted aryl group having 6 to 60 ring atoms, a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 60 ring atoms, a substituted or unsubstituted haloalkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 50 carbon atoms, a substituted or unsubstituted aryloxycarbonyl group having 6 to 60 ring atoms, a substituted or unsubstituted arylcarbonyl group having 6 to 60 ring atoms, a substituted or unsubstituted alkoxycarbonyl group having 1 to 50 carbon atoms, a substituted or unsubstituted carbamoyl group, a substituted or unsubstituted arylsulfonyl group having 6 to 60 ring atoms, a substituted or unsubstituted alkylsulfonyl group having 1 to 50 carbon atoms, a substituted or unsubstituted arylsulfinyl group having 6 to 60 ring atoms, a substituted or unsubstituted alkylsulfinyl group having 1 to 50 carbon atoms, a substituted or unsubstituted alkylcarbonyl group having 1 to 50 carbon atoms, a halogen atom, a cyano group, and a nitro group. R ¹ to R ⁴ units that are adjacent to each other may link with each other to form ring structures.

R ⁵ and R ⁶ are independently a substituted or unsubstituted heteroaryl group having 5 to 60 ring atoms, a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted aryl group having 6 to 60 ring atoms, a substituted or unsubstituted cycloalkyl group having 3 to 50 carbon atoms, or a substituted or unsubstituted haloalkyl group having 1 to 50 carbon atoms.

The nitrogen-containing heterocyclic derivative shown by Formula 82 may be any one of the derivatives shown by Formula 83 below.

Formula 83:

Furthermore, the material of the semi-crystalized organic layer 86 may include a material shown by Formula 84 below.

Formula 84:

In the formula, R ¹ and R ² may each independently represent a hydrogen atom, a halogen atom, a cyano group, an alkyl group having 1 to 20 carbon atoms, an arylamino group having 6 to 40 carbon atoms, a haloalkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 40 nuclear carbon atoms, or a substituted or unsubstituted heterocyclic group having 2 to 40 nuclear carbon atoms. Substituents that are adjacent to each other may link with each other to form rings. Y ₁ and Y ₂ each represent a hydrogen atom or an unsubstituted monovalent group. n represents an integer from 1 to 12. If n is greater than or equal to 2, the plurality of units R ¹ and R ² may each be the same or different.

Y ₁ and Y ₂ may each independently be a hydrogen atom, a substituted or unsubstituted aryl group having 6 to 40 nuclear carbon atoms, an alkyl group having 1 to 20 carbon atoms, or a substituted or unsubstituted heterocyclic group having 2 to 40 nuclear carbon atoms.

Examples of the alkyl group having 1 to 20 carbon atoms include a methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, s-butyl group, t-butyl group, isobutyl group, n-pentyl group, n-hexyl group, n-nonyl group, n-decyl group, n-undecyl group, n-heptyl group, n-octyl group, n-dodecyl group, n-tridecyl group, n-tetradecyl group, n-hexadecyl group, n-pentadecyl group, n-heptadecyl group, neopentyl group, n-octadecyl group, 1-methylpentyl group, 2-methylpentyl group, 1-pentylhexyl group, 1-butylpentyl group, 1-heptyloctyl group, cyclopentyl group, 3-methylpentyl group, cyclooctyl group, cyclohexyl group, 3, 5-tetramethylcyclohexyl group, and the like.

Examples of the haloalkyl group having 1 to 20 carbon atoms include a fluoromethyl group, difluoromethyl group, trifluoromethyl group, pentafluoroethyl group, and the like.

Examples of the alkoxy group having 1 to 20 carbon atoms include groups shown with -OY. For example, Y is the same as the Y described with the alkyl group above.

Examples of the arylamino group having 6 to 40 carbon atoms include a diphenylamino group or the like, or a methyl group, a phenyl group, a naphthyl group, an anthracenyl group, a triphenylenyl group, a fluoranthenyl group, or a biphenyl group having a diphenylamino group or an amino group as a substituent, and the like.

Examples of the aryl group having 6 to 40 nuclear carbon atoms include a phenyl group, a naphthyl group, a biphenyl group, an anthracenyl group, and a triphenylenyl group. Examples of the substituent include a methyl group, an ethyl group, a cyclohexyl group, an isopropyl group, a butyl group, a naphthyl group, a phenyl group, and the like.

Examples of the substituted or unsubstituted heterocyclic group having 2 to 40 carbon atoms include a 1-pyrrolyl group, a 2-pyrrolyl group, a 3-pyrrolyl group, a pyrazinyl group, a 2-pyridinyl group, a 2-imidazopyridinyl group, a 3-imidazopyridinyl group, a 5-imidazopyridinyl group, a 6-imidazopyridinyl group, a 7-imidazopyridinyl group, a 8-imidazopyridinyl group, a 3-pyridinyl group, a 4-pyridinyl group, a 2-furyl group, a 3-furyl group, a 2-benzofuranyl group, a 3-benzofuranyl group , a 4-benzofuranyl group, a 5-benzofuranyl group, a 6-benzofuranyl group, a 7-benzofuranyl group, a 1-isobenzofuranyl group, a 3-isobenzofuranyl group, a 4-isobenzofuranyl group, a 5-isobenzofuranyl group, a 6-isobenzofuranyl group, a 7-isobenzofuranyl group, a 2-quinolyl group, a 3-quinolyl group, a 4-quinolyl group, a 5-quinolyl group, a 6-quinolyl group, a 7- quinolyl group, a 8-quinolyl group, a 2-quinoxalinyl group, a 5-quinoxalinyl group, a 6-quinoxalinyl group, a 1-carbazolyl group, a 2-carbazolyl group, a 3-carbazolyl group, a 4-carbazolyl group, a 9-carbazolyl group, a 3-furazanyl group, a 2-thienyl group, a 3-thienyl group, a 2-methylpyrrol-1-yl group, a 2-methylpyrrol-3-yl group, a 2-methylpyrrol-4-yl group, a 2-methylpyrrol-5-yl group, a 3-methylpyrrol-1-yl group, a 3-methylpyrrol-2-yl group, a 3-methylpyrrol-4-yl group, a 3-methylpyrrol-5-yl group, β-carbolin-1-yl, β-carbolin-3-yl, β-carbolin-4-yl, β-carbolin-5-yl, β-carbolin-6-yl, β-carbolin-7-yl, β-carbolin-8-yl, β-carbolin-9-yl, 1-isoquinolyl, 3-isoquinolyl, 4-isoquinolyl, 5-isoquinolyl, 6-isoquinolyl, 7-isoquinolyl, 8-isoquinolyl, a 1-phenanthridinyl group, a 2-phenanthridinyl group, a 3-phenanthridinyl group, a 4-phenanthridinyl group, a 6-phenanthridinyl group, a 7-phenanthridinyl group, an 8-phenanthridinyl group, a 9-phenanthridinyl group, a 10-phenanthridinyl group, a 1-imidazolyl group, a 2-imidazolyl group, a 1-pyrazolyl group, a 1-indolizinyl group, a 2-indolizinyl group, a 3-indolizinyl group , 5-indolizinyl group, 6-indolizinyl group, 7-indolizinyl group, 8-indolizinyl group, a 1-acridinyl group, a 2-acridinyl group , 3-acridinyl group, a 4-acridinyl group, a 9-acridinyl group, a 1-indolyl group, a 2-indolyl group, a 3-indolyl group, a 4-indolyl group, a 5-indolyl group, a 6-indolyl group, a 7-indolyl group, a 1-isoindolyl group, a 2-isoindolyl group, a 3-isoindolyl group, a 4-isoindolyl group, a 5-isoindolyl group, a 6-isoindolyl group, a 7-isoindolyl group, a 1, 7-phenanthrolin-2-yl group, a 1, 7-phenanthrolin-3-yl group, a 1, 7-phenanthroline-4-yl group, a 1, 7-phenanthroline-5-yl group, a 1, 7-phenanthroline-6-yl group, 1, 7-phenanthrolin-8-yl group, a 1, 7-phenanthroline-9-yl group, a 1, 7-phenanthroline-10-yl group, a 1, 8-phenanthroline-2-yl group, a 1, 8-phenanthroline-3-yl group, a 1, 8-phenanthroline-4-yl group, a 1, 8-phenanthroline-5-yl group, 1, 8-phenanthroline-6-yl group, a 1, 8-phenanthroline-7-yl group, a 1, 8-phenanthroline-9-yl group, a 1, 8-phenanthroline-10-yl group, a 1, 9-phenanthroline-2-yl group, a 1, 9-phenanthroline-3-yl group, a 1, 9-phenanthroline-4-yl group, a 1, 9-phenanthroline-5-yl group, a 1, 9-phenanthroline-6-yl group, a 1, 9-phenanthroline-7-yl group, a 1, 9-phenanthroline-8-yl group, a 1, 9-phenanthroline-10-yl group, a 1, 10-phenanthroline-2-yl group, 1, 10-phenanthroline-3-yl group, a 1, 10-phenanthroline-4-yl group, a 1, 10-phenanthroline-5-yl group, a 2, 7-phenanthroline-1-yl group, a 2, 7-phenanthroline-3-yl group, a 2, 7-phenanthrolin-4-yl group, a 2, 7-phenanthroline-5-yl group, a 2, 7-phenanthroline-6-yl group, a 2, 7-phenanthroline-8-yl group, a 2, 7-phenanthroline-9-yl group, a 2, 7-phenanthroline-10-yl group, a 1-phenazinyl group, a 2-phenazinyl group, a 2, 8-phenanthroline-1-yl group, a 2, 8-phenanthroline-3-yl group, a 2, 8-phenanthroline -4-yl group, a 2, 8-phenanthroline-5-yl group, a 2, 8-phenanthroline-6-yl group, a 2, 8-phenanthroline-7-yl group, a 2, 8-phenanthroline-9-yl group, a 2, 8-phenanthroline-10-yl group, a 2, 9-phenanthroline-1-yl group, a 2, 9-phenanthroline-3-yl group, a 2, 9-phenanthroline-4-yl group, a 2, 9-phenanthroline-5-yl group, a 2, 9-phenanthroline-6-yl group, a 2, 9-phenanthroline-7-yl group, a 2, 9-phenanthroline-8-yl group, a 2, 9-phenanthroline-10-yl group, a 1-germafluorenyl group, a 2-germafluorenyl group, a 3-germafluorenyl group, a 4-germafluorenyl group, a 2-oxadiazolyl group, a 5-oxadiazolyl group, a 2-t-butylpyrrole-4-yl group, a 3- (2-phenylpropyl) pyrrol-1-yl group, a 2-methyl-1-indolyl group, a 4-methyl-1-indolyl group, a 2-methyl-3-indolyl group, a 4-methyl-3-indolyl group, a 1-phenothiazinyl group, a 2-phenothiazinyl group, a 3-phenothiazinyl group, a 4-phenothiazinyl group, a 10-phenothiazinyl group, a 1-phenoxazinyl group, a 2-phenoxazinyl group, a 3-phenoxazinyl group, a 4-phenoxazinyl group, a 10-phenoxazinyl group, a 2-oxazolyl group, a 4-oxazolyl group, a 5-oxazolyl group, a 2-t-butyl-1-indolyl group, a 4-t-butyl-1-indolyl group, a 2-t-butyl-3-indolyl group, a 4-t-butyl-3-indolyl group, a 1-dibenzofuranyl group, a 2-dibenzofuranyl group, a 3-dibenzofuranyl group, a 4-dibenzofuranyl group, a 1-dibenzothiophenyl group, a 2-dibenzothiophenyl group, a 3-benzothiophenyl group, a 4-dibenzothiophenyl group, a 1-silafluorenyl group, a 2-silafluorenyl group, a 3-silafluorenyl group, a 4-silafluorenyl group, and the like.

The substituent is a methyl group, ethyl group, cyclohexyl group, isopropyl group, butyl group, naphthyl group, phenyl group, or the like.

R ₁ and R ^- ₂ may link to form a ring. For example, a benzene ring, cyclohexyl ring, or naphthyl ring is formed.

While the embodiments of the present invention have been described, the technical scope of the invention is not limited to the above described embodiments. It is apparent to persons skilled in the art that various alterations and improvements can be added to the above-described embodiments. It is also apparent from the scope of the claims that the embodiments added with such alterations or improvements can be included in the technical scope of the invention.

The operations, procedures, steps, and stages of each process performed by an apparatus, system, program, and method shown in the claims, embodiments, or diagrams can be performed in any order as long as the order is not indicated by “prior to, ” “before, ” or the like and as long as the output from a previous process is not used in a later process. Even if the process flow is described using phrases such as “first” or “next” in the claims, embodiments, or diagrams, it does not necessarily mean that the process must be performed in this order.

List of Reference Numerals

10: organic layer, 15: emission layer, 20: anode, 30: cathode, 40: encapsulation layer, 50: encapsulation layer, 60: sealing substrate, 70: hole transport region, 72: hole injection layer, 74: hole transport layer, 76: electron barrier layer, 80: electron transport region, 82: hole barrier layer, 84: electron transport layer, 86: semi-crystalized organic layer, 88: electron injection layer, 90: glass substrate, 95: organic layer, 100: organic light-emitting diode, 200: portable terminal, 202: chassis, 204: display section, 210: portable terminal, 212: chassis, 214: display section, 220: portable terminal, 222: chassis, 224: display section, 230: notebook computer, 232: chassis, 234: display section, 240: television apparatus, 242: chassis, 244: display section, 250: smart glasses, 252: chassis, 254: display section, 260: smart watch, 262: chassis, 264: display section, 500: organic light-emitting diode, 510: organic layer, 515: emission layer, 570: hole transport region, 572: hole injection layer, 574: hole transport layer, 576: electron barrier layer, 580: electron transport region, 582: hole barrier layer, 584: electron transport layer, 588: electron injection layer

Claims

An organic light-emitting diode comprising:

a first electrode;

a second electrode;

an emission layer provided between the first electrode and the second electrode; and

a semi-crystalized organic layer that is provided between the first electrode and the emission layer, and has a particles diameter less than or equal to 100 nm.
The organic light-emitting diode according to Claim 1, wherein

a film thickness of the semi-crystalized organic layer is less than or equal to 30 nm.
The organic light-emitting diode according to Claim 1, wherein

a film thickness of the semi-crystalized organic layer is less than or equal to 20 nm.
The organic light-emitting diode according to Claim 1, wherein

a film thickness of the semi-crystalized organic layer is less than or equal to 10 nm.
The organic light-emitting diode according to any one of Claims 1 to 4, wherein

the particle diameter of the semi-crystalized organic layer is less than or equal to 20 nm.
The organic light-emitting diode according to any one of Claims 1 to 5, wherein

the first electrode is a cathode, and

the second electrode is an anode.
The organic light-emitting diode according to Claim 6, further comprising:

an electron injection layer provided between the first electrode and the semi-crystalized organic layer, wherein

the semi-crystalized organic layer is provided in contact with the electron injection layer.
The organic light-emitting diode according to any one of Claims 1 to 5, wherein

the first electrode is an anode, and

the second electrode is a cathode.
The organic light-emitting diode according to any one of Claims 6 to 8, wherein

a film thickness of the second electrode is less than or equal to 15 nm.
The organic light-emitting diode according to any one of Claims 6 to 9, wherein

a film thickness of an electron transport region between the second electrode and the emission layer is greater than a film thickness of a hole transport region between the anode and the emission layer.
The organic light-emitting diode according to any one of Claims 6 to 10, further comprising:

a hole transport layer provided between the emission layer and the anode, wherein

the hole transport layer is not doped with a P-type dopant.
The organic light-emitting diode according to any one of Claims 1 to 5, wherein

the first electrode is a cathode,

the second electrode is an anode, and

the semi-crystalized organic layer is provided both between the cathode and the emission layer and between the anode and the emission layer.
An electronic device comprising the organic light-emitting diode according to any one of Claims 1 to 12.
A display apparatus comprising the organic light-emitting diode according to any one of Claims 1 to 12.