JP2013026299A - Organic light-emitting layer material, coating liquid for forming organic light-emitting layer, organic light-emitting element and light source device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light source device which ensures highly efficient white light emission while reducing the number of films.SOLUTION: In the light source device having multiple organic light-emitting elements each having a lower electrode, an upper electrode, and a charge transport layer and a luminous layer interposed between the lower electrode and the upper electrode, organic light-emitting elements having different luminous colors are arranged in the plane. In at least one organic light-emitting element of blue color out of the multiple organic light-emitting elements, the luminous layer contains a host and a first dopant, and the first dopant contains a first functional group. Concentration of the first dopant in a region of the luminous layer on the side where the upper electrode exists is higher than that in a region where the lower electrode exists, or the concentration of the first dopant in a region of the luminous layer on the side where the lower electrode exists is higher than that in a region where the upper electrode exists.

Description

  The present invention relates to an organic light emitting layer material, a coating liquid for forming an organic light emitting layer, an organic light emitting element, and a light source device.

  The manufacturing method of the organic LED is roughly divided into a vacuum deposition method and a coating method. Among them, the coating method has advantages such as easy formation of a large area and high material utilization efficiency. As a method of obtaining a white light source device by a coating method, (1) organic light emitting elements that emit blue, green, and red light are arranged on a plane, and 2) a light emitting layer that emits blue, green, and red light respectively. There is a method of laminating (3) one light emitting layer that emits light of each color of blue, green, and red.

  In the method (1) using the organic light emitting element that emits blue, green and red, respectively, the number of layers to be laminated with the blue light emitting element is increased. Therefore, it is required to reduce the number of layers. Conventionally, high-efficiency organic light-emitting devices having a blue light-emitting layer include anode / hole injection layer / hole transport layer / electron blocking layer / blue light-emitting layer / hole blocking layer / electron transport layer / electron injection layer / The cathodes are arranged in the order of the cathodes and are reported in Patent Document 1.

JP-A-9-63770

  The conventional organic light emitting device has a problem that it is difficult to control the concentration of the dopant because there is no desired functional group in the dopant and the charge transport layer. In addition, since the conventional high-efficiency light-emitting element has a large number of stacked layers, there is a problem that a lot of labor and cost are required in the manufacturing process. This problem was particularly noticeable in blue.

  The objective of this invention is providing the organic light emitting element and light source device which implement | achieve highly efficient light emission with few laminations.

  The features of the present invention for solving the above-described problems are as follows.

  A light source device having a plurality of organic light emitting elements each having a lower electrode, an upper electrode, and a charge transport layer and a light emitting layer disposed between the lower electrode and the upper electrode, Different organic light emitting elements are arranged, and in the at least one blue organic light emitting element among the plurality of organic light emitting elements, the light emitting layer includes a host and a first dopant, and the first dopant includes a first And the concentration of the first dopant is higher in the region where the upper electrode is present in the light emitting layer than in the region where the lower electrode is present, or in the light emitting layer The region on the side where the lower electrode is present is either higher than the region on the side where the upper electrode is present.

  According to the present invention, it is possible to provide an organic light emitting element and a light source device that have a small number of stacked layers and realize high efficiency light emission. Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments.

It is sectional drawing in the light source device of Example 1 in this invention. It is sectional drawing in one Embodiment of the organic light emitting element in this invention. It is sectional drawing of the light source device of the comparative example 1. It is sectional drawing of the light source device of Example 2 in this invention. It is sectional drawing in the light source device of the comparative example 4. The summary table of the material used by each layer of Examples 1-9 and comparative examples 1-4. It is a block diagram of the light source device of this invention.

  Hereinafter, the present invention will be described in detail with reference to the drawings.

  In a high-efficiency organic light-emitting device using a conventional blue phosphorescent material, an electron blocking layer or a hole blocking layer having a high minimum triplet excitation energy (T1) has been used in order to suppress energy transfer from the blue dopant.

  FIG. 1 is a cross-sectional view of an embodiment of a light source device according to the present invention.

  The substrate 1 is a glass substrate. However, it is not limited to a glass substrate, and a plastic substrate or a metal substrate provided with an appropriate water permeability lowering protective film can also be used.

  The lower electrode 2 is an anode. Transparent electrodes such as ITO and IZO are used. However, the present invention is not limited to these, and a laminated body such as Al or Ag, a combination of Mo, Cr, a transparent electrode and a light diffusion layer, or the like can also be used. Further, the lower electrode is not limited to the anode, and a cathode can also be used. In that case, a laminated body of Al, Mo, Al and Li, an alloy such as AlNi, or the like is used. Moreover, you may use transparent electrodes, such as ITO and IZO.

  The upper electrode 9 is a cathode. A laminate of Al, an electron-injecting LiF, an alkali metal fluoride such as Li20, or an oxide is used. Further, a co-deposited material of Al and alkali metal is also used. A laminate of a transparent electrode such as ITO or IZO and an electron injecting electrode such as MgAg or Li can also be used. However, the present invention is not limited to these, and MgAg or an Ag thin film can be used alone. Further, when ITO or IZO is formed by sputtering, a buffer layer may be provided in order to reduce damage caused by sputtering. A metal oxide such as molybdenum oxide or vanadium oxide is used for the buffer layer. When the lower electrode is a cathode as described above, the upper electrode is an anode. In that case, a transparent electrode such as ITO or IZO is used. Further, a metal thin film such as an Ag thin film can be used. When a transparent electrode such as ITO or IZO is formed by sputtering, a buffer layer may be provided in order to reduce damage caused by sputtering. A metal oxide such as molybdenum oxide or vanadium oxide is used for the buffer layer.

  The hole injection layer 3 is a layer for injecting holes from the lower electrode 2. A single layer or a plurality of layers may be provided. The hole injection layer 3 is preferably a conductive polymer such as PEDOT (poly (3,4-ethylenedioxythiophene)): PSS (polystyrene sulfonate). In addition, polypyrrole-based or triphenylamine-based polymer materials can be used. Further, phthalocyanine compounds and starburst amine compounds that are often used in combination with a low molecular weight (weight average molecular weight 10,000 or less) material system are also applicable.

  The hole transport layer 4 is a layer for efficiently injecting holes from the hole injection layer 3 into the light emitting layer. As the hole transport layer, a homopolymer or a copolymer of fluorene, carbazole, arylamine or the like is used. As the copolymer, a material having a thiophene-based or pyrrole-based skeleton can also be used. A polymer having a skeleton such as fluorene, carbazole, arylamine, thiophene, or pyrrole in the side chain can also be used. Further, the polymer is not limited, and a starburst amine compound, an arylamine compound, a stilbene derivative, a hydrazone derivative, a thiophene derivative, and the like can also be used. Alternatively, a polymer containing the above material may be used. Further, the present invention is not limited to these materials, and two or more of these materials may be used in combination.

  In general, in the case of a blue phosphorescent light emitting element, it is necessary to use a material having a high electron blocking performance, that is, a so-called lowest empty orbit (LUMO) energy as a hole transport layer material. The material is different from a material that easily injects holes into the red and green light emitting layers. Therefore, in the blue phosphorescent light emitting element, it is necessary to install a material different from the hole transport material used for the red and green light emitting layers as an electron blocking layer between the hole transport layer and the light emitting layer. However, in the present invention, it is not necessary to form such an electron blocking layer, and the number of stacked layers can be reduced.

  The bank 8 is formed to separate light emitting layers having different emission colors. The material is preferably photosensitive polyimide. However, it is not limited to photosensitive polyimide, and an acrylic resin or the like can also be used. Non-photosensitive materials can also be used.

  The light emitting layers 5-1, 2 and 3 are layers for obtaining light emission of a desired light emission color. The light emitting layers 5-1, 2 and 3 include hosts 11-1, 2 and 3 and dopants 12-1, 2 and 3. As the dopant, a fluorescent compound or a phosphorescent compound can be used. However, it is desirable to use a phosphorescent dopant in order to obtain high efficiency light emission. The material for forming the light emitting layers 5-1, 2 and 3 includes the hosts 11-1, 2 and 3, a red dopant 12-1, a green dopant 12-2 and a blue dopant 12-3. However, a red light emitting layer and a green light emitting layer may be mixed to form a red green light emitting layer. In that case, the red-green light emitting layer includes a host, a red dopant 12-1, and a green dopant 12-2. The light emitting layers 5-1, 2 and 3 may contain a charge transport material (a hole transport material or an electron transport material) in addition to the host and the dopant. They are used to improve the charge balance in the light emitting layer. Further, the light emitting layer may include a binder polymer.

  An appropriate functional group is imparted to the dopant 12-3, and the dopant 12-3 is localized on the surface of the light emitting layer 5-3 on the side where the charge transport layer is present. Further, a functional group may be added to the charge transport material. Below, the case where a functional group is provided to the charge transport material will be described.

  By providing a functional group imparted to the dopant 12-3 and a functional group imparted to the charge transport material, for example, by providing an alkyl group having 4 or more carbon atoms in both the dopant 12-3 and the charge transport material, Due to the interaction between the alkyl chains, the dopant 12-3 is localized in the vicinity of the charge transport layer. In this case, due to the functional group of the dopant 12-3 and the functional group of the charge transport material, the dopant 12-3 in the light emitting layer is attracted to the surface of the light emitting layer on the side where the charge transport layer is present. Therefore, a pseudo laminate can be formed by a single application.

  At this time, the dopant 12-3 forms a concentration distribution in the light emitting layer, and the position where the concentration of the dopant 12-3 peaks in the film thickness direction of the light emitting layer is present on the charge transport layer side from the center of the light emitting layer. It will be. Further, in the film thickness direction of the light emitting layer, the concentration of the dopant 12-3 from the position where the concentration of the dopant 12-3 reaches a peak toward the surface where the charge transport layer in the light emitting layer does not exist when the light emitting layer is formed. Decreases monotonically. When the interaction between the dopant 12-3 and the charge transport material is used, a hydroxy group or a carboxyl group may be used as the functional group of the dopant 12-3 and the functional group of the charge transport material.

Further, by providing a substituent capable of forming a hydrogen bond to the functional group of the dopant 12-3 and the functional group of the charge transport material, the interaction between the dopant 12-3 and the charge transport material is enhanced, and the dopant 12-3 Is localized in the vicinity of the charge transport layer. Although the following aspects can be considered as a substituent which can form a hydrogen bond, it is not this limitation. As a substituent capable of forming a hydrogen bond, at least one kind of the following embodiments may be present, and two or more kinds may be present. It is desirable to select only one of the following embodiments as a substituent capable of forming a hydrogen bond. Thereby, the hydrogen bond in dopant 12-3 can be suppressed.
(1) The functional group of the dopant 12-3 is a hydroxy group, and the functional group of the charge transport material is a carboxyl group.
(2) The functional group of the dopant 12-3 is a carboxyl group, and the functional group of the charge transport material is a hydroxy group.
(3) The functional group of the dopant 12-3 is an amide group, and the functional group of the charge transport material is an acyl group.
(4) The functional group of the dopant 12-3 is an acyl group, and the functional group of the charge transport material is an amide group.
(5) The functional group of the dopant 12-3 is an amino group, and the functional group of the charge transport material is a hydroxy group.

  Examples of the acyl group include an alkanoyl group such as a carboxyl group and an acetyl group, a benzoyl group, a sulfonyl group, and a phosphonoyl group. The functional group described above may be directly imparted to the dopant 12-3 or the main skeleton of the charge transport material, but may be imparted via an amide bond or an ester bond.

In addition, by forming the functional group of the dopant 12-3 as a perfluorophenyl group and the functional group of the charge transport material as a phenyl group, a strong intermolecular attractive force similar to a hydrogen bond is formed. In summary, the following modes are considered as the functional group of the dopant 12-3 and the functional group of the charge transport material. At this time, it is sufficient that at least one kind of the lower aspect is present, and two or more kinds may be present.
(1) The functional group of the dopant 12-3 and the functional group of the charge transport material are alkyl groups having 4 or more carbon atoms.
(2) The functional group of the dopant 12-3 and the functional group of the charge transport material form a hydrogen bond.
(3) The functional group of the dopant 12-3 is a perfluorophenyl group, and the functional group of the charge transport material is a phenyl group.

  Functional groups may be imparted to all dopants 12-3 included in the light emitting layer 5-3, or functional groups may be imparted to some of the dopants 12-3. Moreover, the functional group may be provided to all the charge transport materials included in the charge transport layer, or the functional group may be provided to some of the charge transport materials.

  As the host 11, it is preferable to use a triphenylamine derivative, a carbazole derivative, a fluorene derivative, an arylsilane derivative, or the like. In addition, a metal complex of 8-quinolinol can also be used. In addition, binder polymers such as polycarbonate, polystyrene, acrylic resin, polyamide, and gelatin can be used together. In order to obtain efficient light emission, the excitation energy of the host 11 is preferably sufficiently larger than the excitation energy of the dopant 12. Therefore, the band gap of the host is usually larger than the band gap of the luminescent dopant (the energy difference between the highest occupied orbit (HOMO) and the lowest empty orbit (LUMO)). Since the band gaps of blue, green, and red dopants are usually blue> green> red, the host band gap is also blue host> green host> red host. A host material with a large band gap usually has a deep HOMO energy and a shallow LUMO energy. Therefore, the blue host usually has the deepest HOMO energy. The excitation energy is measured using an emission spectrum.

  An Ir complex is used as the red dopant. Further, various metal complexes such as Pd, Pt, Al, Zn, DCM ([2-[(E) -4- (dimethylamino) styryl] -6-methyl-4H-pyran-4-ylidene] malononitrile), triazine Organic materials such as derivatives can also be used.

  An Ir complex is used as the green dopant. In addition, various metal complexes such as Pd, Pt, Al, and Zn, and organic materials such as coumarin dyes, quinacridones, and triazine derivatives can also be used.

  An Ir complex is used as the blue dopant. In addition, various metal complexes such as Pd, Pt, and Al, and organic materials such as styrylamine and triazine derivatives can also be used.

  The hole blocking layers 6-1, 2, and 3 are layers for preventing holes from moving from the light emitting layer to the electron transporting layer. Moreover, it also has a role which prevents the excitation energy of a luminescent dopant from moving to a hole-blocking layer or an electron carrying layer. Examples of the material for the hole blocking layer include bis (2-methyl-8-quinolinolato) -4- (phenylphenolato) aluminum (hereinafter referred to as BAlq), tris (8-quinolinolato) aluminum (hereinafter referred to as Alq3), Tris (2,4,6-trimethyl-3- (pyridin-3-yl) phenyl) borane (hereinafter 3TPYMB), 1,4-Bis (triphenylsilyl) benzene (hereinafter UGH2), oxadiazole derivative, triazole derivative , Fullerene derivatives, phenanthroline derivatives, quinoline derivatives, benzimidazole derivatives, and the like. The layer used as the hole blocking layer of the blue phosphorescent light-emitting layer needs to use a material having a deepest energy of the highest occupied orbit (HOMO). The hole blocking layer needs to have HOMO energy sufficiently deeper than the HOMO energy of the light emitting layer in order to prevent hole injection from the light emitting layer to the electron transport layer. Further, in order to prevent the excitation energy of the luminescent dopant from moving, the excitation energy of the hole blocking layer needs to be sufficiently larger than that of the luminescent dopant. For this purpose, it is necessary to have a LUMO energy and a deep HOMO energy that are sufficiently shallower than that of a normal light-emitting dopant. As described above, the HOMO energy of the host and dopant usually increases in the order of blue, green and red. Accordingly, the HOMO energy of the blue hole blocking layer needs to be deepest. Also, from the viewpoint of energy suppression, it usually has the shallowest LUMO energy. From the viewpoint of hole blocking, the hole blocking layer material for blue can be used for green and red. However, a hole blocking layer having a deep HOMO energy and a shallow LUMO energy has a problem that stability and electron transport properties are lowered. Therefore, it is desirable to select separate hole blocking layers for blue, green, and red from the viewpoint of improving performance and stability in all emission colors.

  The electron transport layer 7 is a layer for transporting electrons to the light emitting layer through the hole blocking layer. Examples of the material for the electron transport layer include bis (2-methyl-8-quinolinolato) -4- (phenylphenolato) aluminum (hereinafter, BAlq), tris (8-quinolinolato) aluminum (hereinafter, Alq3), Tris. (2,4,6-trimethyl-3- (pyridin-3-yl) phenyl) borane (hereinafter referred to as 3TPYMB), 1,4-Bis (triphenylsilyl) benzene (hereinafter referred to as UGH2), oxadiazole derivative, triazole derivative, Fullerene derivatives, phenanthroline derivatives, quinoline derivatives, benzimidazole derivatives, and the like can be used.

FIG. 2 is a top view of the light source device according to the embodiment of the present invention shown in FIG. In this light source device, the lower electrode 2-1 has a light emitting layer that emits red light, 2-2 light green, and 2-3 light blue.
By adjusting the voltage applied between the lower electrodes 2-1, 2-2 and 2-3 and the upper electrode 9, a desired emission color such as white can be obtained.

  The present invention will be described in more detail with reference to specific examples. The following examples show specific examples of the contents of the present invention, and the present invention is not limited to these examples, but by those skilled in the art within the scope of the technical idea disclosed in this specification. Various changes and modifications are possible.

  In FIG. 6, what summarized the content of the material used by each layer of Examples 1-9 and Comparative Examples 1-4 is demonstrated.

  A cross-sectional view of the light source device of the first embodiment is shown in FIG. The following materials were used for each layer.

  A glass substrate was used for the substrate 1, and ITO was used for the lower electrode 2. For the hole injection layer 3, PEDOT (poly (3,4-ethylenedioxythiophene)): PSS (polystyrene sulfonate) was used. A triphenylamine polymer was used for the hole transport layer 4.

  BAlq was used for the host 11-1 of the light emitting layer 5-1. On the substrate 1, light emitting layers 5-1, 2, and 3 having different emission colors are formed in a direction along the main surface.

  Further, an Ir complex represented by [Chemical Formula 1] was used as the dopant 12-1 (red dopant).

  A material represented by [Chemical Formula 2] was used for the host 11-2 of the light emitting layer 5-2.

  As the dopant 12-2 (green dopant), an Ir complex represented by [Chemical Formula 3] was used.

  A material represented by [Chemical Formula 4] was used for the host 11-3 of the light emitting layer 5-3.

  For the dopant 12-3 (blue dopant), an Ir complex represented by [Chemical Formula 5] was used.

  [Chemical Formula 5] includes a fluoroalkyl group.

  In the light emitting layer 5-3, the dopant 12-3 is 1% by weight with respect to the host 11-3. The coating liquid for forming the light emitting layer 5-3 was prepared so that toluene was used as a solvent and the weight ratio of solid content to the solvent was 1%. The light emitting layer 5-3 was formed using this coating liquid using the inkjet method.

  BAlq was used for the hole blocking layer 6-1. Further, N-arylbenzimidazoles trimer was used for the hole blocking layer 6-2. For the hole blocking layer 6-3, a material represented by [Chemical Formula 6] was used.

  For the electron transport layer 7, Alq3 was used.

  For the upper electrode 9, a laminated structure of LiF / Al was used.

When a positive potential was applied to the lower electrodes 2-1, 2 and 3 of this example and a negative potential was applied to the upper electrode 9, white light emission consisting of three colors of red, green and blue was obtained. Further, current efficiency at a luminance of 100 cd / m ² was measured. Furthermore, when the concentration distribution of the dopant 12-3 (blue dopant) of the light emitting layer 5-3 was measured by oblique cutting TOF-SIMS, the concentration of the upper surface of the light emitting layer 5-3 was found to be the same as the central portion of the light emitting layer 5-3. In comparison, it was confirmed that it was 5 times or more. As described above, since a large amount of the dopant 12-3 is present on the upper surface of the light emitting layer 5-3, the organic light emitting device emits light without transferring energy from the dopant 12-3 to the hole transport layer 4. Will improve.

  In Example 1, the concentration of the dopant 12-3 in the light emitting layer 5-3 is such that the electron transport in the light emitting layer 5-3 is higher than the side where the electron transport layer 7 and the upper electrode 9 are not present in the light emitting layer 5-3. The side where the layer 7 and the upper electrode 9 are present is higher. This difference in concentration is considered to be caused by the dopant 12-3 moving to the side where the electron transport layer 7 and the upper electrode 9 are present in the light emitting layer 5-3.

[Comparative Example 1]
In Comparative Example 1, a light source device was produced in the same manner as in Example 1 except that [Chemical Formula 7] was used as the dopant 12-3 (blue dopant) of the light emitting layer 5-3.

  As a result, the efficiency of blue light emission was lower than that of Example 1, and the current efficiency of blue light emission of Example 1 was about 0.6. This is because the luminescent dopant [Chemical Formula 7] is distributed throughout the luminescent layer, so that the excited state energy of the luminescent dopant formed in the vicinity of the hole transport layer 4 moves to the hole transport layer and does not emit blue light. This is because the luminous efficiency was lowered as a whole. In the light emitting layer 5-3 of Example 1, since the dopant 12-3 (blue dopant) is localized near the hole blocking layer, the excited state on the dopant emits light without moving to the hole transporting layer 4. Therefore, the efficiency does not decrease.

[Comparative Example 2]
FIG. 3 is a cross-sectional view of the light source device of Comparative Example 1. In Comparative Example 2, a light source device was produced in the same manner as in Comparative Example 1 except that the electron blocking layer 10 was disposed between the hole transport layer 4 and the light emitting layer 5-3. For the electron blocking layer 10, 4,4'-cyclohexylidenebis [N, N-bis (4-methylphenyl) -benzenamine] (hereinafter, TAPC) was used. As a result, the efficiency of blue light emission was improved as compared with Comparative Example 1, and the current efficiency of blue light emission was 1.0 when Example 1 was 1.

  This result shows that, by using TAPC, electrons are blocked by the electron blocking layer 10, and the excited state formed in the light emitting dopant 12-3 emits light without moving to the hole transport layer 4, so that the efficiency is improved. It is thought that it improved. Thus, in Example 1, the current efficiency equivalent to that of Comparative Example 2 can be obtained without forming the electron blocking layer 10 as in Comparative Example 2. Therefore, with the configuration of Example 1, the number of film forming steps can be reduced, and a highly efficient light-emitting light source device can be obtained more simply.

  A cross-sectional view of the light source device of Example 2 is shown in FIG. In Example 2, [Chemical 8] is used for the hole transport layer 4, [Chemical 9] is used for the dopant 12-3, and the same material as 6-2 is used for the hole blocking layer 6-3. A light source device was produced in the same manner as described above.

  When a positive potential was applied to the lower electrodes 2-1, 2 and 3 of this example and a negative potential was applied to the upper electrode 9, white light emission consisting of three colors of red, green and blue was obtained.

  [Chemical Formula 8], which is the material of the hole transport layer 4 of this example, has an OH group, and [Chemical Formula 9], which is the dopant 12-3, has a COOH group. The dopant 12-3 forms a high-concentration region in the vicinity of the interface with the hole transport layer 4 due to the hydrogen bond between both functional groups. Therefore, highly efficient light emission can be obtained without transferring energy to the hole blocking layer 6-3.

  In Example 2, the concentration of the dopant 12-3 in the light emitting layer 5-3 is more positive in the light emitting layer 5-3 than on the side where the hole transport layer 4 and the lower electrode 2 are not present in the light emitting layer 5-3. The side where the hole transport layer 4 and the lower electrode 2 exist is higher. This difference in concentration is considered to be caused by the dopant 12-3 moving to the side where the hole transport layer 4 and the lower electrode 2 are present in the light emitting layer 5-3.

  [Chemical 9] includes a carboxyl group.

[Comparative Example 3]
The light source device of Comparative Example 3 was produced in the same manner as in Example 2 except that [Chemical 7] was used as the dopant 12-3.

  As a result, the efficiency of blue light emission was lower than that of Example 2, and the current efficiency of blue light emission was 0.7 when the current efficiency of Example 2 was 1. This is because the luminescent dopant [Chemical Formula 7] is distributed throughout the luminescent layer, and thus the excited state energy of the luminescent dopant formed in the vicinity of the hole blocking layer 6 has moved to the hole blocking layer and no longer emits blue light. This is because the luminous efficiency was lowered as a whole.

[Comparative Example 4]
FIG. 5 is a cross-sectional view of the light source device of Comparative Example 4. In Comparative Example 4, a light source device was produced in the same manner as in Comparative Example 3 except that [Chem. 6] was used for the hole blocking layer 6-3. As a result, the efficiency of blue light emission was improved as compared with Comparative Example 1, and the current efficiency of blue light emission was 1.0 when Example 2 was 1.

  As a result, by using [Chemical 6] in the hole blocking layer 6-3, the holes are blocked by the hole blocking layer 6-3, and the excited state formed in the light emitting dopant 12-3 is also a hole. Since light is emitted without moving to the blocking layer 6-3, the efficiency is considered to be improved.

  In this way, by using different materials for the hole blocking layer 6-3 and the hole blocking layer 6-2, the same efficiency as that of the second embodiment can be obtained. If the hole blocking layer 6-3 and the hole blocking layer 6-2 are made of different materials, the films 6-2 and 6-3 must be formed separately. In the case of Example 2, since the hole blocking layers 6-2 and 6-3 are the same material, the hole blocking layers 6-2 and 6-3 can be formed simultaneously. Therefore, compared with the comparative example 4, even if the number of film forming steps is reduced once, the same efficiency can be obtained.

  In Example 3, a light source device was produced in the same manner as in Example 1 except that the compound of [Chemical Formula 10] was used as the dopant 12-3.

  As in Example 1, white light emission was obtained, and the current efficiency of blue light emission was 0.9, assuming that Example 1 was 1.

  [Chemical Formula 10] includes an alkyl group.

  In Example 4, a light source device was produced in the same manner as in Example 1 except that the compound of [Chemical Formula 11] was used as the dopant 12-3.

  As in Example 1, white light emission was obtained, and the current efficiency of blue light emission was 1.0 compared to Example 1.

  [Chemical Formula 11] includes a siloxy group.

  In Example 5, a light source device was produced in the same manner as in Example 2 except that the compound of [Chemical Formula 12] was used as the dopant 12-3.

  As in Example 2, white light emission was obtained, and the current efficiency of blue light emission was 0.9, assuming that Example 2 was 1.

  [Chemical Formula 12] includes an acyl group.

  In Example 6, a light source device was produced in the same manner as in Example 2 except that the compound of [Chemical Formula 13] was used as the dopant 12-3.

  As in Example 2, white light emission was obtained, and the current efficiency of blue light emission was 1.0 when Example 2 was 1.

  In addition, [Chemical Formula 13] includes an acyl group.

  In Example 7, the compound of [Chemical Formula 14] was used for the hole transport layer 4 and the compound of [Chemical Formula 15] was used for the dopant 12-3. Other than that was the same as that of Example 2, and produced the light source device.

  As in Example 2, white light emission was obtained, and the current efficiency of blue light emission was 0.9, assuming that Example 2 was 1.

  In addition, [Chemical 15] includes an acyl group and a perfluorophenyl group.

  In Example 8, a light source device was produced in the same manner as in Example 1 except that the compound of [Chemical Formula 16] was used as the dopant 12-3.

  As in Example 1, white light emission was obtained, and the current efficiency of blue was 0.9 when Example 1 was 1.

  [Chemical Formula 16] includes a fluoroalkyl group. [Chemical Formula 16] is represented by the following general formula (1).

(Ar1, 2: aromatic hydrocarbon or aromatic heterocycle, M: periodic table group 8, 9, 10 element, R1: alkyl group, fluoroalkyl group, perfluoroalkyl group or siloxy group, R2: alkyl group , Fluoroalkyl group, perfluoroalkyl group, siloxy group or optionally substituted phenyl group, pyridyl group or thiophene group)

  This general formula constitutes a material for forming an organic light emitting element used for the organic light emitting element. Further, a host and a solution are added to the organic light emitting element forming material to constitute an organic light emitting element forming coating solution.

  A sectional view of the light source device of Example 9 is shown in FIG. In Example 9, a light source device was produced in the same manner as in Example 1 except that [Chemical Formula 17] was used as the dopant 12-3.

  As a result, the efficiency of blue light emission was almost the same as that of Example 1, and the current efficiency of blue light emission of Example 1 was about 0.9, which was about 1.

  [Chemical Formula 17] includes a fluoroalkyl group.

  Moreover, the dopant 12-3 prescribed | regulated by Example 1, 3, 4, 8, 9 contains any one or more of an alkyl group, a fluoroalkyl group, and a siloxy group. In addition, the dopant 12-3 defined in Examples 2, 5, 6, and 7 includes one or more of an acyl group, a carboxyl group, and a perfluorophenyl group.

  In Example 1, the concentration of the dopant 12-3 in the light emitting layer 5-3 is higher than that in the light emitting layer 5-3 where the electron transport layer 7 and the upper electrode 9 are not present. And the side where the upper electrode 9 exists is higher. Since the dopant 12-3 includes one or more of an alkyl group, a fluoroalkyl group, and a siloxy group, also in Examples 3, 4, 8, and 9, the dopant 12- of the light emitting layer 5-3 is used. 3 is higher on the side where the electron transport layer 7 and the upper electrode 9 are present in the light emitting layer 5-3 than on the side where the electron transport layer 7 and the upper electrode 9 are not present in the light emitting layer 5-3. .

  In Example 2, the concentration of the dopant 12-3 in the light emitting layer 5-3 is such that the hole transport in the light emitting layer 5-3 is higher than the side where the hole transport layer 4 and the lower electrode 2 are not present in the light emitting layer 5-3. The side where the layer 4 and the lower electrode 2 exist is higher. Since the dopant 12-3 includes one or more of an acyl group, a carboxyl group, and a perfluorophenyl group, also in Examples 5, 6, and 7, the hole transport layer in the light emitting layer 5-3 4 and the side where the hole transport layer 4 and the lower electrode 2 exist in the light emitting layer 5-3 are higher than the side where the lower electrode 2 does not exist.

  The hole transport layer 4 and the electron transport layer 7 are one of charge transport layers. Therefore, the states of Examples 1, 3, 4, 8, and 9 (the concentration of the dopant 12-3 of the light emitting layer 5-3 is higher than that of the light emitting layer 5-3 on the side where the electron transport layer 7 and the upper electrode 9 do not exist). The state in which the side where the electron transport layer 7 and the upper electrode 9 are present in the light emitting layer 5-3 is higher), the states of Examples 2, 5, 6, and 7 (the dopant 12-3 of the light emitting layer 5-3) Is higher on the side where the hole transport layer 4 and the lower electrode 2 are present in the light emitting layer 5-3 than on the side where the hole transport layer 4 and the lower electrode 2 are not present in the light emitting layer 5-3. In general, the concentration of the dopant 12-3 in the light-emitting layer 5-3 is higher on either the side where the upper electrode 9 is present or the side where the lower electrode 2 is present in the light-emitting layer 5-3. It can be said that.

  That is, in the present invention, there is a large concentration difference with respect to the dopant 12-3 between the side where the upper electrode 9 is present and the side where the lower electrode 2 is present in the light emitting layer 5-3. On the other hand, in the light emitting layers 5-1 and 2 to which no functional group is added, the side where the upper electrode 9 is present and the side where the lower electrode 2 are present are almost uniform or the difference in concentration between the dopants 12-1 and 12-2. Even if there is, it is small.

  Here, the side where the electron transport layer 7 and the upper electrode 9 are present in the light emitting layer 5-3 refers to a region from the center to the end in the direction in which the electron transport layer 7 and the upper electrode 9 are located, respectively. The side where the electron transport layer 7 and the upper electrode 9 do not exist in the light emitting layer 5-3 refers to a region from the center to the end in the direction opposite to the direction in which the electron transport layer 7 and the upper electrode 9 are located.

  Further, the side where the hole transport layer 4 and the lower electrode 2 are present in the light emitting layer 5-3 refers to a region from the center to the end in the direction in which the hole transport layer 4 and the lower electrode 2 are located. Further, the side where the hole transport layer 4 and the lower electrode 2 do not exist in the light emitting layer 5-3 is the end portion from the center toward the direction opposite to the direction in which the hole transport layer 4 and the lower electrode 2 are located, respectively. Refers to an area.

  As an example of the present invention, a light source device 19 shown in FIG. 7 was produced. The organic light-emitting element, which is a component of the light source device 19, includes the same substrate 1, lower electrode 2, organic layer 13, and upper electrode 9 as in the first embodiment. The organic light emitting element is sealed with a sealing tube glass 14 with a desiccant so that the organic layer 13 is shielded from the outside air. Further, the lower electrode 2 and the upper electrode 9 are connected to the drive circuit 16 through wirings 15 respectively. And the organic light emitting element with the sealing tube glass 14, and the drive circuit 16 are covered with the housing 18, and become the light source device 18 as a whole. The drive circuit 16 is lit by being connected to an external power source through the plug 17.

DESCRIPTION OF SYMBOLS 1 Substrate 2 Lower electrode 3 Hole injection layer 4 Hole transport layer 5-1, 5-2, 5-3 Light emitting layer 6-1, 6-2, 6-3 Hole blocking layer 7 Electron transport layer 8 Bank 9 Upper electrode 10 Electron blocking layer 11-1, 11-2, 11-3 Host 12-1, 12-2, 12-3 Dopant 13 Organic layer 14 Sealing tube glass 15 Wiring 16 Drive circuit 17 Plug 18 Housing 19 Light source apparatus

Claims (12)

A substrate,
A lower electrode;
An upper electrode;
A light source device having a plurality of organic light-emitting elements each having a charge transport layer and a light-emitting layer disposed between the lower electrode and the upper electrode,
An organic light emitting element having a different emission color is formed in a direction along the main surface on the substrate,
Among the plurality of organic light emitting devices, in at least one organic light emitting device,
The light emitting layer includes a host, a first dopant,
The first dopant includes a first functional group,
Regarding the concentration of the first dopant, a region on the side where the upper electrode exists in the light emitting layer is higher than a region on the side where the lower electrode exists, or a region on the side where the lower electrode exists in the light emitting layer. Is a light source device that is higher than the region on the side where the upper electrode exists. In claim 1,
The difference in the concentration of the first dopant is a light source device that is generated when the first dopant moves to a region on the side where the upper electrode exists in the light emitting layer or a region on the side where the lower electrode exists. In claim 1,
The first dopant is a light source device represented by the general formula (1).
(Ar1, 2: aromatic hydrocarbon or aromatic heterocycle, M: periodic table group 8, 9, 10 element, R1: alkyl group, fluoroalkyl group, perfluoroalkyl group or siloxy group, R2: alkyl group , Fluoroalkyl group, perfluoroalkyl group, siloxy group or optionally substituted phenyl group, pyridyl group or thiophene group) In claim 1,
A light source device, wherein the charge transport layer is an electron transport layer. In claim 1,
The light source device, wherein the charge transport layer is a hole transport layer. In claim 5,
A light source device in which the light emitting layer is adjacent to the hole transport layer. In claim 1,
The light source device wherein the first functional group includes any one or more of an alkyl group, a fluoroalkyl group, and a siloxy group. In claim 1,
The light source device, wherein the first functional group includes one or more of an acyl group, a carboxyl group, and a perfluorophenyl group. In claim 1,
The organic light emitting device having the first dopant is a light source device which is a blue light emitting device. A substrate,
A lower electrode;
An upper electrode;
A light source device having a plurality of organic light-emitting elements each having a charge transport layer and a light-emitting layer disposed between the lower electrode and the upper electrode,
An organic light emitting element having a different emission color is formed in a direction along the main surface on the substrate,
Among the plurality of organic light emitting elements,
The first organic light emitting device includes a first light emitting layer,
The first light emitting layer includes a first host and a first dopant,
The first dopant includes a first functional group,
The second organic light emitting device includes a second light emitting layer,
The second light emitting layer includes a second host and a second dopant,
The second dopant includes a second functional group,
The concentration difference of the first dopant in the region on the side where the upper electrode is present and the region on the side where the lower electrode is present in the first light emitting layer is the upper electrode in the second light emitting layer. The light source device is larger than the concentration difference between the second dopant in the region on the side where the lower electrode exists and the region on the side where the lower electrode exists. An organic light emitting element forming material used for an organic light emitting element,
The organic light emitting element formation material which has a 1st dopant represented by following General formula (1).
(Ar1, 2: aromatic hydrocarbon or aromatic heterocycle, M: periodic table group 8, 9, 10 element, R1: alkyl group, fluoroalkyl group, perfluoroalkyl group or siloxy group, R2: alkyl group , Fluoroalkyl group, perfluoroalkyl group, siloxy group or optionally substituted phenyl group, pyridyl group or thiophene group)   The organic light emitting element formation coating liquid containing the organic light emitting element formation material of Claim 11, a host, and a solution.