JP2015012105A - Organic light-emitting element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve curability and charge transport properties of a conductive resin of an organic light-emitting element.SOLUTION: The organic light-emitting element includes a hole transport layer between a positive electrode layer and a light-emitting layer. The hole transport layer is composed of a curable resin having counter anion and a cross-linked structure. Density of the counter anion in the hole transport layer is higher on the positive electrode side than on the light emitting layer side.

Description

  The present invention relates to an organic light emitting device using a cured resin as a hole transport layer.

  Organic light-emitting elements have a structure in which organic solid materials with a thickness of several tens of nanometers are stacked, and are attracting attention as elements that provide thin, light, and flexible lighting and displays. Further, since it is self-luminous, a high viewing angle is possible, and since the response speed of the illuminant itself is high, it is suitable for high-speed moving image display. Therefore, it is expected as a next-generation flat panel display or sheet display. Furthermore, since uniform light emission from a large area is possible, it has been attracting attention as next-generation illumination.

  Organic solid materials used for organic light emitting devices are roughly classified into low molecular weight and high molecular weight materials. Low molecular weight materials are mainly suitable for forming elements by vacuum deposition. On the other hand, polymer organic materials are suitable for wet processes such as printing and ink jet processes, and are expected due to the advantages of mass productivity, cost reduction of manufacturing processes, and large screens.

  Regardless of whether the vacuum deposition method or the coating method is used, the organic light-emitting device can smoothly inject electrons and holes from the electrode to the light-emitting layer to emit light with high efficiency. A multilayer structure in which several kinds of organic materials are laminated is effective. Further, it is desirable that the density of holes and electrons be balanced without increasing the luminance even if either of the holes and electrons injected into the light emitting layer is excessive.

  In order to solve the above-mentioned problem, as a laminated structure of an organic light emitting device, Patent Document 1 increases the brightness by laminating a plurality of hole transport layers having different thicknesses and mobility between an anode and a light emitting layer. Is possible. In Patent Document 2, it is possible to increase the luminance and adjust the emission band by forming a quantum well structure with hole transport layers having different energy gaps. In Patent Document 3, it is possible to improve luminance by adopting a stacked structure including a hole transport layer containing an acceptor and an electron transport layer containing a donor, and by optimizing the energy level of the acceptor and the donor with respect to the base material.

On the other hand, when a high molecular weight organic material forms a multilayer structure using a wet process, there is a problem that when the organic layer is formed, the already formed layer is melted. As a countermeasure against this, there is a method in which a polymer is cured by heat or light treatment after a curable solution containing a main agent having a curable crosslinking group added to the polymer is applied by a wet process. Since the cured film (cured resin) has a property of being hardly soluble in a solvent, lamination by a wet process becomes easy.
As a hole transport layer having high solvent resistance as described above, in Patent Document 4, a polymerization initiator that is usually added to a curable solution to promote a crosslinking reaction is provided separately from a cured resin. By adding to the cured resin layer, tolerance is ensured, and by suppressing diffusion of the polymerization initiator from the layer adjacent to the light emitting layer to the light emitting layer as much as possible, deterioration of the element can be suppressed.

JP 2011-142365 A JP 2004-031323 A JP 2000-196140 A JP 2008-227483 A

It is a conceptual diagram of the state before and behind hardening of a curable polymer and an ionic polymerization initiator. 1 is a structural diagram of an organic light emitting device. It is an energy diagram of an organic light emitting element. It is an example of a calculation result of electric charge (hole and electron) distribution. It is a structural view of an organic light emitting device using three hole transport layers.

  As described above, a method of introducing a cured resin for realizing a laminated structure of organic elements and a laminated structure in a coating process has been developed. However, in order to achieve high brightness by optimizing the balance between electrons and holes injected into the light emitting layer by adjusting the mobility, energy gap, and energy level as seen in Patent Documents 1-3 above. However, it is necessary to generally improve the constituent materials in accordance with the use conditions such as the emission color. In the above-mentioned Patent Document 4, a cured resin not containing a polymerization initiator is formed on a non-cured resin containing a polymerization initiator as a hole transport layer, so that two hole transport layers are laminated. Therefore, it is necessary to select a combination of solvents that do not dissolve in each other, and it is necessary to select a crosslinking group that promotes the polymerization reaction without adding a polymerization initiator directly to the cured resin layer.

  The present invention relates to a laminated structure of an organic light-emitting element using a coating process, and tolerates organic light-emitting that can increase the luminance without replacing constituent materials for holes injected into the light-emitting layer. An object is to provide an element.

  In order to solve the above problems, the present invention provides an organic light emitting device having a hole transport layer between an anode and a light emitting layer, wherein the hole transport layer is composed of a polymerizable curable resin containing an ion polymerization initiator, The ion polymerization start is composed of a cation and a counter anion, and the concentration of the counter anion on the anode side in the hole transport layer is higher than the concentration of the counter anion on the light emitting layer side in the hole transport layer. It is also characterized by high.

  According to the present invention, both the tolerability and the luminance of an organic light-emitting element that forms a laminated structure by a coating process can be achieved.

Hereinafter, preferred embodiments of the present invention will be described in detail.
<1. Organic Light-Emitting Device Using Cured Resin as Hole Transport Layer>
In the present specification, the “curable polymer” refers to an intermolecular and / or intramolecular cross-linking by initiating a cross-linking reaction of a cross-linking group bonded in a polymer molecule by a curing process such as heat or light. By forming, it means a polymer that can form a cured resin (hereinafter referred to as “cured resin”).

  Furthermore, the “cationically polymerizable ionic polymerization initiator” (hereinafter sometimes referred to as an ionic polymerization initiator) comprises a combination of a positively charged cation molecule and a negatively charged counter anion molecule. The cationic molecule is a compound that is activated by a curing treatment and promotes a crosslinking reaction of a crosslinking group. The counter anion molecule is added in order to keep the positive charge of the cation molecule neutral, and the negatively charged state is a stable molecule.

In FIG. 1, the conceptual diagram of the state after apply | coating a curable polymer and an ion polymerization initiator to a board | substrate, and after a hardening process is shown. The left side of FIG. 1 shows a state before the curing process after the curable polymer and the ionic polymerization initiator are applied to the substrate, and the right side of FIG. 1 shows a state after the curing process. The curable polymer 10 includes a conductive polymer main chain 11 and a crosslinkable functional group side chain 12. The ionic polymerization initiator is composed of a counter anion 13 and a cation 14.
By applying a curing treatment such as heat or light to the curable polymer and the ionic polymerization initiator, the cation 14 activates a crosslinkable functional group, and a bond with another crosslinkable functional group occurs. The crosslinked structure 15 and the cured resin shown in the right figure are formed. In FIG. 1, the case where the crosslinkable functional group rotates and polymerizes is described. However, the bonding of the crosslinkable group does not necessarily need to be based on the circular polymerization. It is considered that the cation 14 becomes a neutral stable molecule in the curing reaction process, and a part or most of it is volatilized with the solvent by the heat treatment. On the other hand, the counter anion 13 remains in the cured resin. Even if another layer (for example, a light emitting layer) is applied to the cured resin thus prepared, the cured resin does not dissolve.

  Furthermore, the positive charge which the cation 14 had is introduce | transduced as a hole of an electroconductive polymer principal chain by combining the curable polymer 10 shown below and an ionic polymerization initiator. The organic layer of a normal organic light emitting element is an insulating resin, and holes are injected from the electrode by an external voltage. In contrast, the present resin has low resistance because holes are introduced into the cured resin in advance even when no voltage is applied. Further, when the concentration of the ion polymerization initiator is increased, the hole density is increased and the cured resin has a low resistance.

  The inventors of the present invention maintain the solvent resistance by causing the concentration of the counter anion to be higher in the curable resin forming the hole transport layer than in the light emitting layer than in the anode and controlling the degree of inclination. As it is, it was found that the holes injected excessively into the light emitting layer can be suppressed and the luminous efficiency can be improved.

FIG. 2 shows an example of a configuration for making the concentration on the anode side higher than that on the light emitting layer side with respect to the concentration of the counter anion. In FIG. 2, two hole transport layers (a first hole transport layer 23 and a second hole transport layer 24) are provided between the anode 22 and the light emitting layer 25 of the organic light emitting device to transport holes. The layer is made of a polymerizable curable resin containing a counter anion of a cationic polymerizable ionic polymerization initiator, and is adjacent to the first hole transport layer 23 made of the first polymerizable curable resin adjacent to the anode and the light emitting layer. The second hole transport layer 24 made of the second polymerizable curable resin is provided, and the counter anion concentration of the first hole transport layer 23 is higher than the counter anion concentration of the second hole transport layer 24. It is a structure of a high organic light emitting element. As long as the hole transport layer maintains a distribution in which the counter anion concentration is higher on the anode 22 side than on the light emitting layer 25 side, three or more layers may be provided, and the counter anion concentration continuously from the anode toward the light emitting layer. It does not matter even if it takes a form that becomes low. Further, an electron transport layer may be provided between the light emitting layer 25 and the cathode 27. Note that the hole transport layer is also referred to as a hole injection layer.
<2. Change in luminous efficiency of organic light-emitting device depending on the concentration of the ionic polymerization initiator
FIG. 2 shows an embodiment of the organic light emitting device 201 of the present invention. An anode (positive electrode) 22 (for example, indium tin oxide (ITO) which is a transparent electrode) is laminated on the glass substrate 21. A light emitting layer 25 is sandwiched between an anode (negative electrode) 22 and a cathode 27 (for example, Al). Between the anode 22 and the light emitting layer 25, two hole transport layers (a first hole transport layer 23 and a second hole transport layer 24) are laminated. More preferably, the electron transport layer 26 is laminated between the cathode 27 and the light emitting layer 25. In the present invention, a hole transportable curable resin is used for the first hole transport layer 23 and the second hole transport layer 24, and an ionic polymerization initiator is added to the cured resin. By setting the ion polymerization initiator concentration to be the first hole transport layer 23> the second hole transport layer 24, the hole density after curing (and the counter anion density) is the first hole transport layer 23. > The second hole transport layer 24 is obtained, and the tolerance by the cured resin is ensured and the luminance is increased.

  The anode 22 is formed by patterning indium tin oxide (ITO) on the glass substrate 21, for example. For example, the cathode 27 is formed by sequentially forming a first hole transport layer 23, a second hole transport layer 24, and a light emitting layer 25 on the anode 22 of the ITO glass substrate 21. It is formed by depositing aluminum (Al) on top. In the organic light emitting device 201 of the present invention, the anode 22, the second hole transport layer 24, the light emitting layer 25 and the cathode 27 are sandwiched between the glass substrate 21 and the sealing glass plate, and then the glass substrate 21 and the sealing glass plate. Are preferably bonded together using a curable resin such as a photo-curable epoxy resin.

  In the organic light-emitting device of the present invention, the hole transport layer is manufactured using the above-described cured resin. A positive hole transport layer can be manufactured using the means conventionally used in the said technical field. For example, a solution made of an organic solvent to which the curable polymer 10 and an ionic polymerization initiator are added is applied on the anode 22 patterned on the glass substrate 21 by a wet process such as a spin coating method, a printing method, or an ink jet method. Then, it may be manufactured by forming a resin by the curing treatment described above. The present invention has two or more hole transport layers, and starts ion polymerization in the first hole transport layer 23 adjacent to the anode 22 and the second hole transport layer 24 adjacent to the light emitting layer 25. It has an organic light-emitting element structure in which the agent concentration is “first hole transport layer 23> second hole transport layer 24”, and is excellent in ensuring tolerance and improving luminance specific to the cured resin.

  When the light emitting layer 25 is laminated on the surface of the hole transport layer manufactured using the above-described cured resin, for example, by the wet process described above, the hole transport layer is formed by the organic solvent contained in the polymer solution of the light emitting layer 25. It can suppress dissolving. For example, a hole transport layer produced using a resin formed from the curable polymer of the present invention usually has a remaining film ratio in the range of 60 to 100%, typically 80 to 99%. It is a range. The resin having organic solvent resistance expressed by the above remaining film ratio has high curability. Therefore, by using the resin of the present invention for the hole transport layer, it becomes possible to improve the productivity of the organic light emitting device by a wet process.

  Furthermore, the addition concentration of the ionic polymerization initiator for causing the curing reaction to proceed is usually in the range of 0.01% to 50%, typically 0.1 to 30%.

  The simulation described below shows that the distribution of electron and hole densities in the light emitting layer changes based on the concentration of the ionic polymerization initiator, and as a result, the light emission efficiency also changes. With respect to the concentration of the ion polymerization initiator, by setting “first hole transport layer 23> second hole transport layer 24”, “hole density in first hole transport layer 23> second The hole density in the hole transport layer 24 ”. In the following simulation, the change in the hole density in the first hole transport layer 23 and the second hole transport layer 24 affects the charge distribution injected into the light emitting layer, resulting in a change in luminance. The phenomenon of charge movement and light emission process in the organic light emitting device is not limited to the phenomenon represented by the following mathematical model.

FIG. 3 shows a diagram of the studied device. HOMO (Highest Occupied Molecular Orbital) is the energy required to inject holes into each layer, LUMO (Lowest Unoccupied Molecular Orbital) is used to inject electrons. Represents the required energy. For the first hole transport layer 23, the second hole transport layer 24, and the light emitting layer 25, typical numerical values shown in the figure were set. An anode potential was set for ITO, and the hole concentration was constant (1.0 × 10 ²¹ holes / cm 3) in ITO. A cathode potential was set for Al, and the electron density was constant (1.8 × 10 ²³ particles / cm ³ ) in Al. The ion polymerization initiator added to the hole transport layer was an ion polymerization initiator (formula (7)) to be post-treated, and the concentration was 0, 3, or 10 wt%. Assuming that the positive charge of the added ion polymerization initiator is completely introduced as holes in the cured resin that forms the hole transport layer, the hole density is 0, 1.9 × 10 ¹⁹ , 6.3 × 10 ¹⁸ pieces / It was cm ^3.

In the simulation, the advection diffusion equation (electron or hole continuity equation), ∂ρ / ∂t = ∇ · {(μρE + D∇ρ)} − G, is used to calculate the carrier density ρ (electron density ρ _e or the time variation of the representative one of the hole density [rho _e) was calculated until a steady state. The first term of {} on the right side of the above formula represents the mobility μ, the current density due to the electric field E, the second term represents the diffusion current density, and the charge flowing into a certain area (here, the element of the finite element method) The difference between the flowed out charges indicates that the charge density changes with time. G is an electron-hole recombination probability (the density of electrons and holes where electrons and holes disappear due to light emission), and is the number of charges lost due to recombination (light emission). Here, as a model of the electron-hole recombination probability G, a Langevin type recombination model G = (eμ / ε) ρ _e · ρ _h is assumed. Here, e is an elementary charge, and ε is a dielectric constant of the resin. Since the charge density ρ changes with the passage of time after voltage application, the Laplace equation Δφ = ρ _total / ε, E = ∇φ (ρ _total is the sum of charges of electrons, holes, and anions) Updated sequentially. Also, energy barrier ΔE when electrons or holes pass through the interface of each layer (for holes, difference in HOMO energy of adjacent layer, for electrons, difference in LUMO energy of adjacent layer) , The mobility at the interface was assumed to be μ · exp (−ΔE / k _B T). k _B is the Boltzmann constant and T is the temperature (T = 300K here). The larger the barrier ΔE, the smaller the mobility at the interface and the harder it is to move.

In any organic layer (hole transport layer and light-emitting layer), the mobility, diffusion coefficient, and dielectric constant of electrons and holes are the same as typical values of organic matter (mobility = 1.0 × 10 ^-8 [m ² / V / sec], diffusion coefficient = 5.0 × 10 ⁻⁶ [m ² / sec], dielectric constant ε = 4.0). The mobility differs by several orders of magnitude depending on the type of resin and whether it is an electron or a hole, but here we use a calculation model that uses the same value to focus on the difference in the hole density introduced into the hole injection layer in advance. Simplified.

FIG. 4 shows the calculation result of the charge distribution when 5 V is applied between the anode ITO and the cathode Al. FIG. 4A shows the case where the concentration of the ionic polymerization initiator in the first hole transport layer 23 and 2 is 10 wt% (described as 10 wt% / 10 wt%) (“in the first hole transport layer "Addition amount / addition amount in the second hole transport layer", the same applies hereinafter)). A thick solid line represents hole density × electron density in the light emitting layer, which is proportional to the luminance distribution. In the light emitting layer, about 2.6 × 10 ¹⁷ holes / cm ³ of holes are injected from the hole transport layer. On the other hand, the electron density injected from the cathode Al is 2 × 10 ¹⁴ atoms / cm ³ at the interface between the light emitting layer and the cathode, and rapidly decays along the interface between the light emitting layer and the hole transport layer. This is because holes are excessively injected into the light emitting layer, and electrons injected from the cathode are recombined at the interface between the light emitting layer and the cathode and do not easily reach the hole transport layer. Along with this, the luminance distribution is high at the interface between the light emitting layer and the cathode and rapidly attenuates along the interface between the light emitting layer and the hole transport layer.

FIG. 4B shows the case where the ion polymerization initiator of the first hole transport layer 23 is 10 wt% and the ion polymerization initiator of the second hole transport layer 24 is 0 wt% (10 wt% / 0 wt%). The distribution of holes and electrons. The hole density in the light emitting layer is about 0.8 × 10 ¹⁷ holes / cm ^3, which is smaller than 30% compared with Table 1 (a). On the other hand, the electron density injected from the cathode Al is injected at about 1 × 10 ¹⁴ atoms / cm ³ over the entire light emitting layer. Therefore, the luminance distribution is almost constant in the light emitting layer, and light is emitted from the entire light emitting layer. The luminance integrated over the entire light emitting layer is reduced to (b) of 0.8 when Table 1 (a) is 1.0.

FIG. 4 (c) shows the case where the ion polymerization initiator of the first hole transport layer 23 is 10 wt% and the ion polymerization initiator of the second hole transport layer 24 is 3 wt% (10 wt% / 3 wt%). The distribution of holes and electrons. The hole density in the light emitting layer is about 2.0 × 10 ¹⁷ holes / cm ³ , and 75% is maintained as compared with Table 1 (a). The electron density injected from the cathode Al is about 1 × 10 ¹⁴ to 1 × 10 ¹⁵ pieces / cm ³ over the entire light emitting layer. Compared to Table 1 (a), the luminance distribution approaches a constant value in the light emitting layer, and the entire light emitting layer emits light. The luminance integrated over the entire light emitting layer is improved to 1.2 when Table 1 (a) is 1.0.

From the above, it was shown that the luminance can be improved by setting the hole density of the hole transport layer to “electrode side> light emitting layer side” depending on the addition concentration of the ion polymerization initiator.
<3. Conductive polymer main chain of curable polymer>
The hole transporting monomer contained in the conductive polymer main chain of the curable polymer of the present invention is a known monomer used to produce a resin that forms a charge transporting layer or a light emitting layer of an organic light emitting device. If it is. A hole-transporting monomer is bonded to two or more adjacent monomers. A hole transporting monomer bonded at two points is linear, and a hole transporting monomer bonded at two or more points is branched. Examples of the charge transporting and light emitting monomers include, but are not limited to, arylamine, stilbene, hydrazone, carbazole, aniline, oxazole, oxadiazole, benzoxazole, benzooxadiazole, benzoquinone, quinoline, and isoquinoline. Quinoxaline, thiophene, benzothiophene, thiadiazole, benzodiazole, benzothiadiazole, triazole, perylene, quinacridone, pyrazoline, anthracene, rubrene, coumarin, naphthalene, benzene, biphenyl, terphenyl, anthracene, tetracene, fluorene, phenanthrene, pyrene, Chrysene, pyridine, pyrazine, acridine, phenanthroline, furan and pyrrole, and compounds having these derivatives as skeletons It can be mentioned.
Preferably, the linear and branched conjugated monomers are of the formulas (1) to (3):

It is selected from compounds having a skeleton represented by:
Where
R1 to R7 are independently of each other hydrogen, halogen, cyano, nitro, linear, branched or cyclic alkyl having 1 to 22 carbon atoms, linear, branched or cyclic having 2 to 22 carbon atoms. Alkenyl, straight chain, branched or cyclic alkynyl having 2 to 22 carbon atoms, aryl having 6 to 21 carbon atoms, heteroaryl having 12 to 20 carbon atoms, aralkyl having 7 to 21 carbon atoms, and 13 to 20 carbon atoms It is preferably selected from the group consisting of heteroarylalkyl, hydrogen, halogen, cyano, nitro, linear, branched or cyclic alkyl having 1 to 22 carbon atoms, aryl having 6 to 21 carbon atoms, carbon number 12 More preferably, it is selected from the group consisting of ˜20 heteroaryl and C 7-21 aralkyl, hydrogen, halogen, C 1-10 linear, branched or cyclic alkyl and C 6— Further selected from the group consisting of 10 aryls It is particularly preferred that it is selected from the group consisting of hydrogen, bromine, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl and phenyl.

  The above groups are preferably unsubstituted or substituted with one or more halogens, and more preferably unsubstituted.

  m1 and m2 are each independently an integer of 0 to 5, and more preferably 0 or 1.

  n1 and n2 are each independently preferably an integer of 0 to 4, more preferably 0 or 1.

  In the present specification, “aralkyl” means a group in which one of hydrogen atoms of alkyl is substituted with aryl. Suitable aralkyls include, but are not limited to, benzyl, 1-phenethyl, 2-phenethyl, and the like.

  In the present specification, “arylalkenyl” means a group in which one of the alkenyl hydrogen atoms is substituted with the aryl. Suitable arylalkenyl includes, but is not limited to, styryl.

  In the present specification, “heteroaryl” means that one or more carbon atoms of aryl are each independently substituted with a heteroatom selected from a nitrogen atom (N), a sulfur atom (S), and an oxygen atom (O). Means the group formed. For example, “heteroaryl having 12 to 20 carbon atoms” and “heteroaryl having 12 to 20 members (ring)” are one or more aromatic groups containing at least 12 and at most 20 carbon atoms. It means a group in which carbon atoms are independently substituted with the above heteroatoms. In this case, substitution with N or S includes substitution with N-oxide or S oxide or dioxide, respectively. Suitable heteroaryl include, but are not limited to, furanyl, thienyl, pyrrolyl, imidazolyl, pyrazolyl, triazolyl, tetrazolyl, thiazolyl, oxazolyl, isoxazolyl, oxadiazolyl, thiadiazolyl, isothiazolyl, pyridyl, pyridazinyl, pyrazinyl, pyrimidinyl, quinolinyl, Examples thereof include isoquinolinyl and indolyl. In the present specification, “heteroarylalkyl” means a group in which one of the hydrogen atoms of alkyl is substituted with the heteroaryl. In the present specification, “halogen” means fluorine, chlorine, bromine or iodine.

Particularly preferably, the charge transporting or luminescent monomer is triphenylamine, N- (4-butylphenyl) -N ′, N ″ -diphenylamine, 9,9-dioctyl-9H-fluorene, N-phenyl-9H -Carbazole, N, N'-diphenyl-N, N'-bis (3-methylphenyl)-[1,1'-biphenyl] -4,4'-diamine and N, N'-bis (3-methylphenyl) ) -N, N′-bis (2-naphthyl)-[1,1′-biphenyl] -4,4′-diamine, and compounds having these derivatives as a skeleton.
<4. Crosslinkable functional group side chain of curable polymer>
The “crosslinkable functional group” contained in the side chain of the curable polymer of the present invention may be any known functional group that can be polymerized by cationic polymerization. For example, a cyclic ether group typified by an epoxy group or an oxetane group or a known aromatic crosslinking group may be used, and a plurality of these may be combined. Examples of the crosslinking group of the aromatic group include, but are not limited to, a group having thiophene, styrene, pyrrole, and benzocyclobutene as a skeleton.

  Preferably, the cross-linking group of the aromatic group has the formulas (4) to (6):

It is selected from a group having a skeleton represented by: The cyclic ether ring crosslinking group easily undergoes a curing reaction and can be cured at a lower temperature. There is a tendency that the mobility of a resin cured using an aromatic crosslinking group is high.
A resin prepared using a curable polymer comprising a main chain of a charge transporting or luminescent monomer having the above skeleton and a crosslinkable functional group side chain improves the curability of the resulting resin, and The charge transport capability can be improved.

The main chain may be either linear or branched, and the composition ratio when both linear and branched monomers are used is appropriately set according to the characteristics to be imparted to the curable polymer. do it. For example, in order to improve curability, the curable polymer used as the hole transport layer of the organic light-emitting device of the present invention is preferably in a form containing more branched monomers than linear monomers. In order to improve conductivity, a form containing a large amount of linear monomers is desirable.
<5. Ion polymerization initiator>
In the present specification, the “cationic polymerizable ion polymerization initiator” is composed of a combination of a positively charged cation molecule and a negatively charged counter anion molecule. The cationic molecule is a compound that is activated by a curing treatment and promotes a crosslinking reaction of a crosslinking group. The counter anion molecule is added in order to keep the positive charge of the cation molecule neutral, and the negatively charged state is a stable molecule.

  For example, examples of the cationic molecule include iodonium salts, sulfonium salts, and ferrocene derivatives. The above cations are preferable because of high reactivity for initiating cationic polymerization.

  Particularly preferably, the cationically polymerizable ion polymerization initiator is selected from compounds represented by the following chemical formulas (7) to (9).

X = Sb ₆ , (C ₆ F ₅ ) ₄ B, CF ₃ SO ₃ , PF ₆ , BF ₄ , C ₄ F ₉ SO ₃ , CH ₃ C ₆ H ₄ SO ₃ , any one of R ¹¹ to R ¹⁵ is independently of each other a hydrogen atom, a halogen atom, a cyano group, a nitro group, a linear, branched or cyclic alkyl group having 1 to 22 carbon atoms, a linear or branched chain having 2 to 22 carbon atoms. Or cyclic alkenyl group, linear or branched alkynyl group having 2 to 22 carbon atoms, aryl group having 6 to 21 carbon atoms, heteroaryl group having 12 to 20 carbon atoms, or 7 to 21 carbon atoms It is preferably selected from the group consisting of an aralkyl group and a heteroarylalkyl group having 13 to 20 carbon atoms, a hydrogen atom, a halogen atom, a cyano group, a nitro group, a straight chain, branched or cyclic group having 1 to 22 carbon atoms. Alkyl group, aryl group having 6 to 21 carbon atoms, and 12 to 2 carbon atoms More preferably, it is selected from the group consisting of 0 heteroaryl group and aralkyl group having 7 to 21 carbon atoms, particularly preferably a hydrogen atom.
It is preferable that s1, s2, t1, t2, and t3 are integers of 0 to 5 independently of each other.
X is a counter anion, both of which are negatively charged molecules that are stable.
<6. Production of curable polymer>
The crosslinkable polymer of the present invention can be produced by polymerizing at least one of the charge transporting or light emitting monomer described above and a monomer containing a crosslinking group by a method known in the art. it can. For example, if the monomer containing a crosslinking group is an aromatic itself or a monomer in which the crosslinking group is bonded to an aromatic group, all monomers have an aromatic ring. In this case, for example, the monomers can be polymerized by cross-coupling aromatic rings contained in each monomer using Suzuki coupling. Suzuki coupling causes a Pd-catalyzed cross-coupling reaction (hereinafter also referred to as “Suzuki reaction”) between an aromatic boronic acid derivative and an aromatic halide. Using the Suzuki reaction, the monomer is polymerized by bonding at least one of the charge transporting or light-emitting monomer and the aromatic rings of the monomer having a crosslinking group and an aromatic group bonded to each other. A polymer composition having a polymerizable crosslinking group contained in the coating solution can be produced.

The Suzuki reaction usually requires a soluble Pd compound in the form of a Pd (II) salt or Pd (0) complex as a catalyst. Aromatic compounds that are substrates for the Suzuki reaction, i.e., 0.01 to 5 mole percent Pd (Ph ₃ P) ₄ , Pd (OAc) ₂ complex with a tertiary phosphine ligand or PdCl, based on the crosslinkable monomer described above ₂ (dppf) complexes are preferably used as Pd catalysts. The Suzuki reaction also requires a base. Aqueous alkali carbonate or bicarbonate is preferably used, and potassium carbonate is more preferably used. As the solvent, N, N-dimethylformamide, toluene, anisole, dimethoxyethane, tetrahydrofuran or the like is preferably used, and toluene is more preferably used. When a nonpolar solvent such as toluene is used, it is preferred to promote the reaction using a phase transfer catalyst such as triscaprylylmethylammonium chloride (Aliquat® 336). By polymerizing each crosslinkable monomer under the above conditions, the curable polymer of the present invention can be produced in a high yield.
<7. Solvent of coating solution>
The coating method as described above can be usually carried out at a temperature range of -20 to 300 ° C, preferably 10 to 100 ° C, particularly preferably 15 to 50 ° C, and as a solvent used in the solution, Although not particularly limited, examples thereof include toluene, chloroform, methylene chloride, dichloroethane, tetrahydrofuran, xylene, mesitylene, anisole, acetone, methyl ethyl ketone, ethyl acetate, butyl acetate, and ethyl cellosolve acetate.
<8. Resin formed by curable polymer and ion initiator>
The cured resin for the hole transport layer used in the organic light-emitting device of the present invention is included in the ion initiator by applying a solution obtained by dissolving a curable polymer and an ion initiator in an organic solvent to a substrate, followed by curing treatment. The cation molecule thus circulates the crosslinkable functional group side chain, and the crosslinkable groups contained in the curable polymer form interpolymer and / or intrapolymer crosslinks to obtain a cured resin. The resin produced by using the polymerizable coating solution of the present invention becomes strong in a network structure by forming the interpolymer and / or intrapolymer crosslinks, and does not dissolve even when another layer is applied. . Furthermore, the positive charges possessed by the cation are introduced as holes in the conductive polymer main chain. The organic layer of a normal organic light emitting element is an insulating resin, and holes are injected from the electrode by an external voltage. In contrast, the present cured resin has low resistance because holes are introduced into the cured resin in advance even when no voltage is applied.

  In the present specification, the “curing treatment” means a treatment in which the crosslinking groups described above are reacted to form intermolecular and / or intramolecular crosslinking. Examples of the curing treatment applied to the curable polymer of the present invention include heating and irradiation with light, microwave, radiation, electron beam and the like. Heat treatment is preferred.

  Particularly preferably, a mixture obtained by mixing the curable polymer of the present invention and the crosslinking initiator described above is subjected to a heat treatment to react the crosslinking groups to form intermolecular and / or intramolecular crosslinking. In this case, it is preferable that the temperature of heat processing is the range of 100-250 degreeC. Moreover, it is preferable that the time of heat processing is the range for 10 to 180 minutes.

  The resin formed by the cured resin used as the hole transport layer in the light emitting device of the present invention usually has a work function in the range of 4 to 7 eV, and typically in the range of 4.7 to 5.8 eV. . The work function can be adjusted by appropriately setting the constituent ratio of the monomer contained in the curable polymer of the present invention. For example, it is desirable that the work function of the cured resin of the present invention be an intermediate value between the work function of a light emitting layer usually used in an organic light emitting device and the work function of an indium tin oxide (ITO) electrode.

The work function of the cured resin used as the hole transport layer of the light emitting device of the present invention is not limited. For example, using a surface analyzer AC-1 manufactured by Riken Keiki, under the condition of an irradiation light amount of 50 nW, The work function can be measured.
<9. Example of making cured resin>
[Curing Polymer Production Example 1]
A linear triphenylamine monomer (formula (10)), a branched triphenylamine monomer (formula (11)), and an oxetane-crosslinked monomer (formula (12)) are polymerized by the Suzuki reaction to obtain a curable polymer. Synthesized. The crosslinkable linear triphenylamine monomer (formula (10)) and branched triphenylamine monomer (formula (11)) have 2 and 3 reaction points, respectively, of the Suzuki reaction, and the main chain is formed by polymerization. Form. Each of the crosslinkable oxetane crosslinked monomers (formula (12)) has one reaction point of the Suzuki reaction, and forms a side chain by polymerization. The crosslinkable oxetane crosslinked monomer (formula (12)) is a monomer having a structure in which a 1-ethyloxetane-1-yl group is bonded to a divalent crosslinking group composed of a combination of phenylene and oxymethylene.

  In a round bottom flask, 4,4′-bis (4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl) -4 ″ -n-butyltriphenylamine (formula (10 )) (0.4 mmol), 4,4 ′, 4 ″ -tribromotriphenylamine (formula (11)) (1.0 mmol), 3- (4-bromophenoxymethyl) 3-ethyloxetane (formula (12) ) (1.2 mmol), tetrakistriphenylphosphine palladium (0.008 mmol), 2 M aqueous potassium carbonate solution (5.3 mmol), Aliquat (registered trademark) 336 (0.4 mmol) and anisole (4 ml) were placed in a nitrogen atmosphere. Stir for 2 hours at ° C.

Crosslinkable linear triphenylamine monomer (Formula (10)): Crosslinkable branched triphenylamine monomer (Formula (11)): Crosslinkable oxetane crosslinked monomer (Formula (12)) = 20:50 The polymer composition A having a cross-linking group having a molecular weight of 40 kDa was obtained. The molecular weight was determined by the number average when measured in terms of polystyrene using gel permeation chromatography. This curable polymer is designated as curable polymer A.
[Creative Polymer Production Example 2]
In the procedure described in the cured polymer preparation example 1, a linear triphenylamine monomer (formula (10)) was converted to 2,7-bis (4,4,5,5-tetramethyl-1,3,2- A curable polymer B having a crosslinking group having a molecular weight of about 40 kDa was prepared in the same manner as above except that dioxaborolan-2-yl) -9,9-dioctyl-9H-fluorene (formula (13)) was changed. Obtained.

[Creative Polymer Production Example 3]
In the procedure described in the cured polymer production example 1, a crosslinkable linear triphenylamine monomer (formula (10)) is converted into 2,7-bis (4,4,5,5-tetramethyl-1,3, A curable polymer C having a crosslinking group having a molecular weight of about 40 kDa was prepared in the same manner as described above except that 2-dioxaborolan-2-yl) -N-phenyl-9H-carbazole (formula (14)) was changed. Obtained.

[Creating Polymer Preparation Example 4]
In the procedure described in the preparation example 1 of the cured polymer, the crosslinkable oxetane crosslinked monomer (formula (3)) is replaced with any of the following aromatic crosslinkable groups (formula (15), formula (16), formula (17)). The curable polymers D, E, and F having a crosslinking group having a molecular weight of about 40 kDa were obtained by the same procedure as described above except that the above was changed.

[Preparation of coating solution]
Any of the above curable polymers A, B and C (4.2 mg), an initiator represented by the formula (7) (wherein R11 and R12 of the cation are H, s1, s2 = 1, counter anion) X = (C ₆ F ₅ ) ₄ B) 0.04, 0.12, 0.42 mg (corresponding to z = 1, 3, 10 wt%, respectively for the curable polymer) (curable polymer) (A was also carried out under the condition of 0 wt% only in A) and dissolved in 1.2 ml of toluene to prepare a coating solution. This coating solution is defined as coating solutions A (z), B (z), and C (z).
[Formation of resin using curable polymer]
Indium tin oxide (ITO) was patterned on a glass substrate with a width of 1.6 mm. On the ITO glass substrate, the coating solution prepared above was spin-coated under the condition of 300 rpm. Then, the ITO glass substrate coated with the polymerizable coating solution is applied to the coating solution containing any of the curable polymers A, B, and C at 180 ° C. on the hot plate and containing the curable polymer D. The liquid was cured by heating on a hot plate at 250 ° C. for 60 minutes, and the curable polymer was polymerized by heating to form a resin. The resins are referred to as cured resins A (z), B (z), C (z), and D (z), respectively.
[Evaluation of remaining film ratio]
The evaluation of the remaining film rate can be performed, for example, by the following procedure. On the anode of the ITO glass substrate, a hole transport layer is produced using a resin formed of the curable polymer of the present invention. The ITO glass substrate on which the hole transport layer is formed is immersed in an organic solvent (for example, toluene) at 20 to 250 ° C. for 10 to 60 seconds. Thereafter, the ITO glass substrate was taken out from the organic solvent, and the absorbance of the thin film before and after immersion was measured. The residual ratio of the thin film (residual film ratio) was determined from the absorbance ratio. Since the absorbance is proportional to the film thickness, the ratio of absorbance (with / without immersion) corresponds to the remaining film ratio (with / without immersion) of the hole transport layer. It is evaluated that the higher the residual film ratio, the higher the organic solvent resistance.

Rinse a thin film of cured resin A (z), B (z), C (z), D (z) with toluene in toluene and measure the absorbance of the thin film before and after rinsing. From the ratio of absorbance before and after rinsing The remaining rate of the thin film (remaining film rate) was determined. All of the resin thin films have a remaining film ratio of 90% or more and have sufficient resistance to dissolution.
[Evaluation of work function]
The work function of the cured resin was determined using a photoelectron yield spectrometer (a surface analyzer AC-1 manufactured by Riken Keiki Co., Ltd., with an irradiation light amount of 50 nW). The work functions of the cured resins A (z) were 5.0 eV, whereas the work functions of the cured resins B (z) and C (z) were 5.2 and 5.3 eV, respectively. From this result, by changing the type of charge transporting or light emitting monomer used in the synthesis of the curable polymer, a resin having a work function intermediate between the light emitting layer and ITO was created, and the organic EL It can be used to create elements. The work functions of the cured resins D (z), E (z), and F (z) were 5.0 eV, which is the same as that of the cured resin A having the same conductive polymer form.
[Hall-only element]
The performance of the cured resin single layer used as the hole transport layer prepared by the above method was evaluated with a hole-only device. The hole-only element is an element in which a cured resin is sandwiched between indium tin oxide ITO as an anode and gold as a cathode.

  The hole-only device is created by the following procedure. In a toluene (440 μL) solution of the curable polymers A, B, and C (20 mg), 0.2, 0.6, and 2 mg of the above-described ion polymerization initiator (z = 1, 3, 10 wt with respect to the curable polymer). %) In toluene (10 μL) was added to prepare a coating solution. The coating solution is spin-coated at a rate of 2000 / min on a glass substrate on which ITO is patterned to a width of 1.6 mm, and the coating solution containing any of curable polymers A, B, and C is on a hot plate. At 120 ° C. for 10 minutes to form cured resins A (z), B (z), and C (z). The coating solution containing the curable polymers D, E, and F is heated on a hot plate at 200 ° C. for 10 minutes to form cured resins D (z), E (z), and F (z). Next, the obtained glass substrate was transferred into a vacuum evaporation machine, and gold (film thickness 30 nm) was evaporated.

  After depositing gold, the substrate is moved into a dry nitrogen environment without opening to the atmosphere, and the sealing glass and ITO substrate in which 0.4 mm of counterbore is put into 0.7 mm non-alkali glass are used as a photocurable epoxy resin. Sealing was performed by bonding together to produce a hole-only element.

  In a hole-only element formed using cured resin A (z), B (z), C (z), D (z), E (z), F (z), the current density at an applied voltage of 1 V is In any cured resin, z increased with increasing. This indicates that the number of introduced holes increases as the concentration of the counter anion of the ion polymerizable initiator increases. Therefore, for example, by providing two hole transport layers, with the first hole transport layer 23 adjacent to the anode and the second hole transport layer 24 adjacent to the light emitting layer, with respect to the ion polymerization initiator, By setting “first hole transport layer 23> second hole transport layer 24”, the effect of the present invention can be exhibited.

In [Preparation of coating solution] of the cured resin A (z), the cation of the initiator represented by the formula (7) (wherein R11 and R12 of the cation are H, and s1, s2 = 1) Anion X = SbF ₆ , CF ₃ SO ₃ , PF ₆ , BF ₄ , C ₄ F ₉ SO ₃ and CH ₃ C ₆ H ₄ SO ₃ are 0.04, 0.12, 0.42 mg (based on the curable polymer) In addition, even when added (corresponding to z = 1, 3, 10 wt%, respectively), the current density at an applied voltage of 1 V increased as z increased in any cured resin.

In the [preparation of coating solution] of the cured resin A (z), an initiator represented by the formula (7) (wherein R11 and R12 of the cation are H and t1, t2, T3 = 1) or XIII Even when 0.04, 0.12, or 0.42 mg of cation and counter anion X = (C ₆ F ₅ ) ₄ B are added (corresponding to z = 1, 3, and 10 wt%, respectively, with respect to the curable polymer). The current density at an applied voltage of 1 V increased with increasing z in any cured resin.

Hereinafter, the present invention will be described more specifically with reference to examples. However, the technical scope of the present invention is not limited to these examples.
<Example 1: Organic light emitting device A using cured resin A as a hole transport layer>
[Creation of positive electrode and hole transport layer]
Using the methods described in [Cure Polymer Preparation Example 1], [Preparation of Coating Solution], and [Formation of Resin Using Curable Polymer], as a hole transport layer on the positive electrode ITO substrate, A cured resin is formed. Here, as the first hole transport layer 23 on the ITO substrate, a cured resin A (added with 10 wt% of an ion polymerization initiator), and further, a second hole transport layer on the first hole transport layer 23. As a layer 24, a cured resin A (added with 3 wt% of an ion polymerization initiator) was laminated. The thicknesses of the first hole transport layer 23 and the second hole transport layer 24 were 30 nm, respectively.
[Creation of light emitting layer material]
In a round bottom flask, 4,4′-bis (4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl) -4 ″ -n-butyltriphenylamine (1) ( 0.4 mmol), 4,4′-dibromotriphenylamine (2) (0.08 mmol), 4,7-dibromo-2,1,3-benzothiadiazole (0.32 mmol), tetrakistriphenylphosphine palladium (0.004 mmol), 2 M potassium carbonate aqueous solution (10.6 mmol), Aliquat (registered trademark) 336 (0.4 mmol) and toluene (7 ml) were added, and the mixture was stirred at 80 ° C. for 48 hours under a nitrogen atmosphere. The reaction solution was poured into a methanol / water mixed solvent (9: 1), and the precipitated polymer was separated by filtration. Purification was performed by repeating reprecipitation twice, and a yellow light-emitting polymer D was obtained.
[Light emitting layer and cathode Al formation]
A yellow light emitting polymer D is spin-coated on a substrate in which a cured resin (10 wt% of an ionic polymerization initiator) and a cured resin A (3 wt% of an ionic polymerization initiator) are laminated on an ITO substrate, and a light emitting layer of 30 nm is laminated. did. An Al electrode having a thickness of 100 nm was deposited on the light emitting layer. After electrode formation, the substrate was moved into a dry nitrogen environment without opening to the atmosphere. A multilayer glass organic light-emitting device was fabricated by sealing an ITO substrate and a sealing glass in which 0.4 mm counterbore was added to 0.7 mm alkali-free glass using a photo-curable epoxy resin. . This organic light emitting device is referred to as organic light emitting device A (10 wt%: 3 wt%).
<Comparative Example 1: Organic light-emitting device having the same ion polymerization initiator in the first hole transport layer and the second hole transport layer>
In the procedure described in Example 1, both the first hole transport layer 23 and the second hole transport layer 24 have a concentration of 10 wt.% With respect to the concentration of the ion polymerization initiator added when preparing the cured resin for the hole transport layer. An organic light-emitting device was produced under the same conditions except that% was added. This organic light emitting device is referred to as organic light emitting device A (10 wt% / 10 wt%).
<Comparative Example 2: Organic light-emitting device in which an ion polymerization initiator is added only to the first hole transport layer>
In the procedure described in Example 1, 10 wt% was added to the first hole transport layer 23 with respect to the concentration of the ion polymerization initiator to be added when the cured resin for the hole transport layer was prepared. An organic light emitting device was produced under the same conditions except that the layer 24 was not added. It was also confirmed that the second hole transport layer 24 proceeded with the curing reaction without adding an ionic polymerization initiator, and the remaining film ratio was 90% or more. This organic light emitting element is referred to as organic light emitting element A (10 wt% / 0 wt%).
<Comparative Example 3: Organic light-emitting device in which more ion polymerization initiator is added to the second hole transport layer than the first>
In the procedure described in Example 1, with respect to the concentration of the ion polymerization initiator to be added when preparing the cured resin for the hole transport layer, 3 wt% is added to the first hole transport layer 23, and the second hole transport layer is added. An organic light emitting device was fabricated under the same conditions except that 10 wt% was added to 24. This organic light emitting device is referred to as organic light emitting device A (3 wt% / 10 wt%).
<Evaluation of organic light emitting device performance>
The performance evaluation of the organic light-emitting elements of Example 1 and Comparative Examples 1, 2, and 3 was performed by measuring a voltage for maintaining a luminance of 1,000 cd / m 2 at room temperature (25 ° C.) in the atmosphere. The organic light emitting device A of Example 1 (10 wt% / 3 wt%) was 6.0 V, while the organic light emitting device A of Comparative Example 1 (10 wt% / 10 wt%) was 6.5 V, Comparative Example 2. In organic light emitting device A (10 wt% / 0 wt%), the voltage was 7.0 V.

This is consistent with the trend shown in the simulation. Further, in the organic light emitting device A of Comparative Example 3 (3 wt% / 10 wt%), it was 6.8 V.
From the above, it was shown that the luminance can be improved by making the hole density on the electrode side in the hole transport layer larger than the hole density on the light emitting layer side, depending on the addition concentration of the ion polymerization initiator.
<Example 2: Organic light emitting device 2 using cured resin D as hole transport layer D>
In Example 1, an organic light-emitting element prepared under the same conditions was used except that the cured resin A forming the first hole transport layer 23 and the second hole transport layer 24 was a cured resin D. D (10 wt% / 3 wt%).
<Comparative Example 4: Organic light-emitting device having the same ion polymerization initiator in the first hole transport layer and the second hole transport layer>
In the organic light-emitting device D of Example 2, both the first hole transport layer 23 and the second hole transport layer 24 are related to the concentration of the ion polymerization initiator to be added when preparing the cured resin for the hole transport layer. An organic light emitting device was produced under the same conditions except that 10 wt% was added. This organic light emitting element is referred to as organic light emitting element D (10 wt% / 10 wt%).
<Comparative Example 5: Organic light-emitting device in which an ion polymerization initiator is added only to the first hole transport layer>
In the procedure described in Example 2, with respect to the concentration of the ion polymerization initiator to be added when preparing the cured resin of the hole transport layer, 10 wt% was added to the first hole transport layer 23, and the second hole transport was added. An organic light emitting device was produced under the same conditions except that the layer 24 was not added. It was also confirmed that the second hole transport layer 24 proceeded with the curing reaction without adding an ionic polymerization initiator, and the remaining film ratio was 90% or more. This organic light emitting element is referred to as organic light emitting element D (10 wt% / 0 wt%).
<Evaluation 2 of organic light emitting device performance>
The performance evaluation of the organic light-emitting devices of Example 2 and Comparative Examples 4 and 5 was performed by measuring a voltage for maintaining a luminance of 1,000 cd / m 2 in the atmosphere at room temperature (25 ° C.).

  In the case of the organic light emitting device D of Example 2 (10 wt% / 3 wt%), it was 5.7 V, whereas in the case of the organic light emitting device D of Comparative Example 4 (10 wt% / 10 wt%), 6.2 V, Comparative Example 5 In the organic light emitting device D (10 wt% / 0 wt%), the voltage was 6.8V.

From the above, it was shown that the luminance can be improved also in this device by setting the hole density of the hole transport layer to the electrode side> the light emitting layer side by the addition concentration of the ion polymerization initiator.
<Example 3: Organic light-emitting device using three hole transport layers>
An organic light emitting device E (10 wt% / 5 wt% / 3 wt%) having the third hole transport layer 28 shown in FIG. 5 was prepared. In the same manner as in Example 1, the cured resin A (ion polymerization initiator added at 10 wt%), and the second hole transport layer 24 on the first hole transport layer 23 as the cured resin A (ion polymerization) The initiator was added at 5 wt%). In addition to this, in this element, a cured resin A (added with 3 wt% of an ion polymerization initiator) was laminated on the second hole transport layer 24 as the third hole transport layer 28. The thicknesses of the first hole transport layer 23, the second hole transport layer 24, and the second hole transport layer 28 were each 20 nm.
<Evaluation 3 of organic light emitting device performance>
The performance evaluation of the organic light-emitting devices of Example 3 and Comparative Examples 4 and 5 was performed by measuring a voltage for maintaining a luminance of 1,000 cd / m 2 at room temperature (25 ° C.) in the atmosphere.

  In the case of the organic light emitting device E of Example 3 (10 wt% / 5 wt% / 3 wt%), it is 5.8 V, and in the organic light emitting device A of Example 1 (10 wt% / 3 wt%), it is more than 6.0 V. It was shown that the brightness can be improved.

  DESCRIPTION OF SYMBOLS 10 ... Curing polymer, 11 ... Conductive polymer principal chain, 12 ... Crosslinkable functional group side chain, 13 ... Counter anion, 14 ... Cation, 15 ... Cross-linked structure, 21 ... Glass substrate, 22 ... Anode, DESCRIPTION OF SYMBOLS 23 ... 1st hole transport layer, 24 ... 2nd hole transport layer, 25 ... Light emitting layer, 26 ... Electron transport layer, 27 ... Cathode, 28 ... 3rd hole transport layer, 201 ... Organic light emitting element

Claims (10)

In the organic light emitting device having a hole transport layer between the anode and the light emitting layer,
The hole transport layer is composed of a cured resin having a counter anion and a crosslinked structure,
The organic light emitting device, wherein the concentration of counter anions in the hole transport layer is higher on the anode side than on the light emitting layer side. The organic light emitting device according to claim 1,
The organic light emitting device, wherein the hole concentration in the hole transport layer is higher on the anode side than on the light emitting layer side. The organic light emitting device according to claim 1 or 2,
In the organic light emitting device, the hole transport layer has a counter anion concentration continuously decreasing from the anode toward the light emitting layer. The organic light emitting device according to any one of claims 1 to 3,
The organic light-emitting element, wherein the curable resin is formed by a curing treatment for a curable polymer and an ionic polymerization initiator. The organic light emitting device according to claim 4,
The curable polymer has a hole transporting monomer in a main chain and a crosslinkable functional group in a side chain. The organic light emitting device according to claim 4,
The hole transporting monomer is a compound represented by any one of the following formulas (1) to (3).
(Where
R ^{1 to} R ⁷ are independently of each other hydrogen, halogen, cyano, nitro, straight chain, branched or cyclic alkyl having 1 to 22 carbon atoms, straight chain, branched or branched carbon atoms having 2 to 22 carbon atoms. Cyclic alkenyl, linear, branched or cyclic alkynyl having 2 to 22 carbon atoms, aryl having 6 to 21 carbon atoms, heteroaryl having 12 to 20 carbon atoms, aralkyl having 7 to 21 carbon atoms, and 13 to 13 carbon atoms Selected from the group consisting of 20 heteroarylalkyl (the above groups are unsubstituted or substituted with one or more halogens);
m1 and m2 are each independently an integer of 0 to 5,
n1 and n2 are each independently an integer of 0 to 4) The organic light emitting device according to claim 4,
The organic light-emitting device, wherein the crosslinkable functional group is a cyclic ether group. The organic light emitting device according to claim 4,
The organic light-emitting device, wherein the crosslinkable functional group is aromatic. The organic light emitting device according to claim 8,
The organic light-emitting device, wherein the aromatic is a compound represented by any one of the following formulas (4) to (6).
The organic light-emitting device according to claim 1,
The organic light-emitting device, wherein the counter anion is a compound represented by any of the following formulas (7) to (9).
X = Sb ₆ , (C ₆ F ₅ ) ₄ B, CF ₃ SO ₃ , PF ₆ , BF ₄ , C ₄ F ₉ SO ₃ , CH ₃ C ₆ H ₄ SO ₃