Organic light-emitting element, film formation method, and film formation apparatus

Abstract

To provide an organic light emitting element including a cathode layer with excellent light transmittance and low resistance.SOLUTION: An organic light emitting element according to one form of the present invention comprises a light emitting layer provided between a cathode layer and an anode layer, an electron injection layer provided between the above cathode layer and the above light emitting layer, a hole injection layer provided between the above anode layer and the above light emitting layer, an electron transport layer provided between the above electron injection layer and the above light emitting layer, and a hole transport layer provided between the above hole injection layer and the above light emitting layer. The above cathode layer is a sputtering layer, contains a first component including at least one of Ag and Al and a second component including at least one of Mg, Li, and Ca, and has a thickness greater than 10 nm and less than 20 nm.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an organic light-emitting element, a film forming method, and a film forming apparatus. [Background technology]

[0002] In an organic light-emitting device, electrons are injected from a cathode electrode into a light-emitting layer, holes are injected from an anode electrode, and the electrons and holes are recombined in the light-emitting layer to generate light. Here, there is a technology that uses an extremely thin semi-transparent silver layer as the cathode electrode (negative electrode layer) of an organic light-emitting device (for example, see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2007-317384 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above technology, the extremely thin silver layer is set to a thickness of 10 nm, so even if the silver layer is semi-transparent, the layer tends to have an island shape, which may increase the resistance of the cathode layer, even though it is semi-transparent.

[0005] In view of the above circumstances, an object of the present invention is to provide an organic light-emitting element that has excellent light transparency and includes a cathode layer with low resistance, and a film-forming method and a film-forming apparatus for forming the cathode layer. [Means for solving the problem]

[0006] In order to achieve the above object, an organic light-emitting device according to one aspect of the present invention includes an emitting layer provided between a cathode layer and an anode layer, an electron injection layer provided between the cathode layer and the emitting layer, The device includes a hole injection layer provided between the anode layer and the light-emitting layer, an electron transport layer provided between the electron injection layer and the light-emitting layer, and a hole transport layer provided between the hole injection layer and the light-emitting layer. The cathode layer is a sputtering layer, which includes a first component including at least one of Ag and Al, and a second component including at least one of Mg, Li, and Ca, and has a thickness greater than 10 nm and less than 20 nm.

[0007] In such an organic light-emitting device, even if the cathode layer of the organic light-emitting device is composed of the above-mentioned first component and second component, the organic light-emitting device will have a cathode layer that has low resistance and excellent light transparency.

[0008] In the organic light-emitting device, the cathode layer may have a higher concentration of the second component on the electron injection layer side than a concentration of the first component.

[0009] In such an organic light-emitting element, carrier injection into the light-emitting layer of the organic light-emitting element is further promoted.

[0010] In the organic light-emitting device, in the cathode layer, the concentration of the first component relative to the concentration of the second component may gradually increase with increasing distance from the electron injection layer.

[0011] In such an organic light-emitting element, carrier injection into the light-emitting layer of the organic light-emitting element is further promoted.

[0012] In the organic light-emitting device, in the cathode layer, the second component may be laminated on the electron injection layer, and the second component and the first component may be laminated alternately.

[0013] In such an organic light-emitting element, carrier injection into the light-emitting layer of the organic light-emitting element is further promoted.

[0014] In order to achieve the above object, a film formation method according to one aspect of the present invention is a film formation method for forming a cathode layer on an electron injection layer included in an organic light emitting element. The cathode layer, which contains a first component including at least one of Ag and Al and has a thickness greater than 10 nm and not greater than 20 nm, is sputter-deposited on the electron injection layer.

[0015] With such a film formation method, even if the cathode layer of the organic light-emitting element is composed of the above-mentioned first component, the organic light-emitting element will have a cathode layer that has low resistance and excellent light transparency.

[0016] In the film formation method, the cathode layer containing the first component and a second component containing at least one of Mg, Li, and Ca may be formed on the electron injection layer by sputtering.

[0017] With such a film formation method, even if the cathode layer of the organic light-emitting element is composed of the first component and the second component, the organic light-emitting element will have a cathode layer that has low resistance and excellent light transmittance.

[0018] In the film formation method, the cathode layer may be formed so that the concentration of the second component is relatively higher on the electron injection layer side than the concentration of the first component.

[0019] According to such a film formation method, in the organic light emitting element, carrier injection into the light emitting layer of the organic light emitting element is further promoted.

[0020] In the above film formation method, a first film formation source containing the first component and a second film formation source containing the second component are prepared as film formation sources, and the film formation source and the electron injection layer are opposed to each other in a first direction. When the cathode layer containing the component of the first film formation source and the component of the second film formation source are formed while the electron injection layer and the film formation source are moved relatively in a second direction intersecting the first direction, the film formation may be performed by arranging the first film formation source and the second film formation source in the second direction so that the second film formation source and the electron injection layer overlap before the first film formation source in the first direction.

[0021] According to such a film formation method, in the organic light emitting element, carrier injection into the light emitting layer of the organic light emitting element is further promoted.

[0022] In order to achieve the above object, a film formation apparatus according to one aspect of the present invention includes a substrate holder, a film formation source, and a moving mechanism. The substrate holder can support a substrate on which an electron injection layer included in an organic light emitting device is exposed toward a film formation source. The film formation source faces the substrate holder in a first direction and has a first sputtering target including at least one of Ag and Al, and a second sputtering target including at least one of Mg, Li, and Ca. The moving mechanism moves the substrate and the film formation source relatively in a second direction intersecting the first direction.

[0023] By using such a film formation apparatus, even if the cathode layer of the organic light-emitting element is composed of the first component and the second component, the organic light-emitting element will have a cathode layer that has low resistance and excellent light transmittance.

[0024] In the film formation apparatus, a partition plate extending in the first direction may be provided between the first sputtering target and the second sputtering target.

[0025] When such a film formation apparatus is used, the sputtering particles from the first film formation source 61 and the second film formation source 62 do not interfere with each other, and the emission amounts of the first film formation source 61 and the second film formation source 62 are stabilized. Effect of the Invention

[0026] As described above, the present invention provides an organic light-emitting element that has excellent light transparency and includes a cathode layer with low resistance, and a film-forming method and a film-forming apparatus for forming the cathode layer. [Brief description of the drawings]

[0027] [Figure 1] 1 is a schematic cross-sectional view showing an organic light-emitting element of the present embodiment. [Diagram 2] 4 is a graph showing the relationship between the concentration of a first component and the concentration of a second component from the interface between a cathode layer and an electron injection layer to the surface of the cathode layer. [Diagram 3] 1 is a schematic cross-sectional view of a main part of a film forming apparatus for carrying out a film forming method according to an embodiment of the present invention. [Figure 4] 1A to 1C are schematic cross-sectional views showing a film forming method according to an embodiment of the present invention. [Diagram 5] Figure (a) is a graph showing the light transmittance (%) in the Ag sputtering layer, and Figure (b) is a graph showing the light transmittance (%) in the AgMg sputtering layer. The horizontal axis is the wavelength of transmitted light. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In each drawing, XYZ axis coordinates may be introduced. In addition, the same reference numerals may be given to the same components or components having the same functions, and after the components are described, the description may be omitted as appropriate. In addition, the numerical values ​​shown below are examples and are not limited to these examples.

[0029] Fig. 1 is a schematic cross-sectional view showing an organic light-emitting element according to the present embodiment, in which a main part of a top-emission type organic light-emitting element 1 is shown as an example.

[0030] The organic light-emitting element 1 includes an emission layer (EML) 10, an electron transport layer (ETL) 21, a hole transport layer (HTL) 22, an electron injection layer (EIL) 31, a hole injection layer (HIL) 32, a cathode layer 41, and an anode layer 42. In the organic light-emitting element 1, the hole injection layer 32, the hole transport layer 22, the emission layer 10, the electron transport layer 21, and the electron injection layer 31 are laminated in this order from the anode layer 42 toward the cathode layer 41.

[0031] The light-emitting layer 10 is provided between the cathode layer 41 and the anode layer 42. The electron injection layer 31 is provided between the cathode layer 41 and the light-emitting layer 10. The hole injection layer 32 is provided between the anode layer 42 and the light-emitting layer 10. The electron transport layer 21 is provided between the electron injection layer 31 and the light-emitting layer 10. The hole transport layer 22 is provided between the hole injection layer 32 and the light-emitting layer 10.

[0032] In the organic light-emitting element 1, light emitted in the light-emitting layer 10 is extracted from the cathode layer 41. A support substrate (not shown) that supports the organic light-emitting element 1 is disposed on the opposite side of the cathode layer 41, i.e., below the anode layer 42. Thin film transistors, circuits such as wiring, an interlayer insulating layer, and the like are disposed on the substrate (none of which are shown). The support substrate may be a flexible substrate or a non-flexible plate-like substrate.

[0033] The cathode layer 41 is composed of a conductive layer having excellent light transmission and low resistance. The cathode layer 41 is a sputtering layer (also called a sputtering film) formed under a reduced pressure atmosphere, and has a thickness of more than 10 nm and not more than 20 nm, preferably 15 nm to 20 nm. The material of the cathode layer 41 contains at least one of Ag and Al. However, from the viewpoint of reducing the work function of the cathode layer 41, it is preferable that the material of the cathode layer 41 contains a first component containing at least one of Ag and Al, and a second component containing at least one of Mg, Li, and Ca. The second component is contained in the first component at 10 atomic % to 20 atomic %.

[0034] The electron injection layer 31 includes at least one of an alkali metal, an alkaline earth metal, an alkali metal fluoride, an alkaline earth metal fluoride, and a lanthanoid. For example, the electron injection layer 31 includes at least one of LiF, CsF, NaF, Ca, Ba, and Yb. The thickness of the electron injection layer 31 is configured to be extremely thin in order to enhance light transmission, and is, for example, 5 nm or more and 10 nm or less.

[0035] When a voltage is applied between the anode layer 42 and the cathode layer 41, holes are injected from the hole injection layer 32 into the hole transport layer 22, and electrons are injected from the electron injection layer 31 into the electron transport layer 21. Then, the holes that have moved through the hole transport layer 22 and the electrons that have moved through the electron transport layer 21 recombine in the light-emitting layer 10, and light is generated in the light-emitting layer 10. The light generated in the light-emitting layer 10 is emitted from the light-emitting layer 10 to each of the anode layer 42 and cathode layer 41 sides.

[0036] The organic light-emitting element 1 is a top-emission type, and the hole injection layer 32, the hole transport layer 22, the light-emitting layer 10, the electron transport layer 21, the electron injection layer 31, and the cathode layer 41 are configured to have high light transmittance for emitted light. In addition, the anode layer 42 is configured to reflect the emitted light. As a result, the emitted light traveling directly from the light-emitting layer 10 toward the cathode layer 41 and the emitted light reflected by the anode layer 42 are combined, and the emitted light in the organic light-emitting element 1 passes through the cathode layer 41 and is emitted to the outside of the organic light-emitting element 1.

[0037] The cathode layer 41 is an alloy layer in which the first component and the second component are dissolved and the second component is uniformly dispersed in the first component. Alternatively, the cathode layer 41 may be configured so that the concentration (atomic %) of the second component is relatively higher than the concentration (atomic %) of the first component on the electron injection layer 31 side. Note that this embodiment also includes a configuration in which the cathode layer 41 is a metal layer containing only the first component.

[0038] For example, FIGS. 2(a) and (b) show the relationship between the concentration of the first component and the concentration of the second component from the interface between the cathode layer and the electron injection layer to the surface of the cathode layer.

[0039] 2(a), in the cathode layer 41, the concentration (atomic %) of the first component relative to the concentration (atomic %) of the second component may gradually increase with increasing distance from the electron injection layer 31. For example, the concentration of the first component relative to the concentration of the second component gradually increases from the electron transport layer 21 side toward the cathode layer 41 side. In FIG. 2(a), a first-order linear function is shown as the relationship between the depth and the concentration of the first component or the concentration of the second component, but the concentration of the first component relative to the concentration of the second component may increase from the interface toward the surface as an n-th order linear function or may increase stepwise.

[0040] Alternatively, as shown in FIG. 2(b), the cathode layer 41 may be stacked on the electron injection layer 31 starting from the second component, and the second component and the first component may be stacked alternately. Here, when the second component and the first component are stacked alternately, as shown in FIG. 2(b), the thickness of the second component may become thinner and the thickness of the first component may become thicker with increasing distance from the electron injection layer 31. Alternatively, when the second component and the first component are stacked alternately, the thickness of the second component and the thickness of the first component may be stacked alternately with the same thickness. Hereinafter, a method for manufacturing the cathode layer 41 having the concentration distribution shown in FIG. 2(a) will be described.

[0041] Fig. 3 is a schematic cross-sectional view of a main part of a film forming apparatus in which the film forming method of the present embodiment is performed. Fig. 3 shows a film forming apparatus 100 that forms a cathode layer 41 on an electron injection layer 31 included in an organic light emitting element 1. In Fig. 3, the direction in which the film forming source 60 faces the substrate 91 or the substrate holder 90 during film formation is defined as the Z-axis direction (first direction). The direction in which the substrate 91 and the film forming source 60 move relatively is defined as the Y-axis direction (second direction). The first direction and the second direction intersect (for example, are perpendicular to each other).

[0042] The film forming apparatus 100 includes a substrate holder 90, a film forming source 60, a moving mechanism 70, and an adhesion prevention plate 95. The substrate holder 90 is capable of supporting a substrate 91. On the film forming surface of the substrate 91, a laminate 50 is provided, on which the light emitting layer 10, the electron transport layer 21, the electron injection layer 31, the hole transport layer 22, the hole injection layer 32, and the anode layer 42 of the organic light emitting element 1 have already been formed.

[0043] During film formation, the substrate 91 is not shielded from the film formation source 60 by the adhesion prevention plate 95, and the adhesion prevention plate 95 is exposed at an opening 96 that is interrupted in the Y-axis direction. In the substrate 91, the electron injection layer 31 included in the organic light-emitting element 1 is exposed toward the film formation source 60. The electron injection layer 31 may be exposed from a mask pattern (not shown).

[0044] The film forming source 60 includes a first film forming source 61, a second film forming source 62, a shutter 67 facing the first film forming source 61, and a shutter 68 facing the second film forming source 62. For example, the first film forming source 61 is a sputtering target containing at least one of Ag and Al as a first component. The second film forming source 62 is a sputtering target containing at least one of Mg, Li, and Ca as a second component.

[0045] The sputtering targets of the first film formation source 61 and the second film formation source 62 are planar targets. The first film formation source 61 and the second film formation source 62 extend in the X-axis direction intersecting (for example, perpendicular to) the Z-axis direction and the Y-axis direction. That is, the sputtering targets have a longitudinal direction in the X-axis direction. In the sputtering targets, the surface facing the substrate 91 is the sputtering surface.

[0046] In addition, a magnet mechanism 67 is provided behind each of the sputtering targets on the opposite side to the sputtering surface. This allows magnetron sputtering deposition in the film deposition apparatus 100. The magnet mechanism 67 can also oscillate in the Y-axis direction behind the sputtering targets. Each of the first film deposition source 61 and the second film deposition source 62 is supplied with discharge power independently from a power source (not shown).

[0047] In the film formation apparatus 100, the first film formation source 61 and the second film formation source 62 are arranged side by side in the Y-axis direction so that when the electron injection layer 31 formed on the substrate 91 and the film formation source 60 move relative to each other, the second film formation source 62 and the substrate 91 overlap before the first film formation source 61 in the Z-axis direction. A partition plate 65 extending in the Z-axis direction is provided between the first film formation source 61 and the second film formation source 62. The partition plate 65 also extends in the X-axis direction. The partition plate 65 has a longitudinal direction in the X-axis direction.

[0048] The movement mechanism 70 moves the substrate 91 and the film formation source 60 relatively in the Y-axis direction (second direction) intersecting the Z-axis direction. For example, the movement mechanism 70 moves the substrate 91 and the film formation source 60 relatively in the Y-axis direction perpendicular to the Z-axis direction. For example, the substrate holder 90 and the adhesion prevention plate 95 are fixed, and the film formation source 60 moves in the scanning direction. Note that the film formation source 60 may be fixed under the opening 96, and the substrate holder 90 and the substrate holder 95 may move in the Y-axis direction.

[0049] 4(a) to 4(c) are schematic cross-sectional views showing the film forming method of the present embodiment. In Fig. 4(a) to 4(c), the shutters 67, 68 are omitted because they are both in an open state.

[0050] When attempting to form a cathode layer 41 on the electron injection layer 31 included in the organic light emitting element 1, for example, sputtering film formation using a two-source film formation source is performed. For example, a first film formation source 61 containing a first component and a second film formation source 62 containing a second component are prepared as the film formation source 60. Note that the film formation source 60 scans once in one direction during sputtering film formation. The substrate 91 is a large substrate, for example, 1.5 m to 3.0 m (Y-axis direction) and 1.5 m to 3.5 m (X-axis direction). The electron injection layer 31 is formed on the outermost surface of the substrate 91 facing the film formation source 60.

[0051] In the film formation method of the present embodiment, the film formation source 60 and the electron injection layer 31 are opposed to each other in the Z-axis direction, and discharge power is supplied to both the first film formation source 61 and the second film formation source 62. Then, the first component of the first film formation source 61 and the second component of the second film formation source 62 are formed on the electron injection layer 31 while the electron injection layer 31 and the film formation source 60 are moved relatively in the Y-axis direction.

[0052] For example, as shown in FIG. 4(a), in the film formation source 60, the first film formation source 61 and the second film formation source 62 are arranged so that when the film formation source 60 is moved in the scanning direction, the second film formation source 62 overlaps with the electron injection layer 31 before the first film formation source 61 in the Z-axis direction.

[0053] As a result, at an arbitrary position P1 on the substrate 91, the sputtering particles 62s emitted from the second film formation source 62 at the beginning of the film formation are preferentially deposited on the electron injection layer 31. In the middle stage of the film formation, as shown in FIG. 4(b), the sputtering particles 62s emitted from the second film formation source 62 and the sputtering particles 61s emitted from the first film formation source 61 are deposited on the electron injection layer 31. In the later stage of the film formation, as shown in FIG. 4(c), the sputtering particles 61s emitted from the first film formation source 61 are preferentially deposited on the electron injection layer 31. As a result, the cathode layer 41 having the concentration distribution shown in FIG. 2(a) is formed on the electron injection layer 31.

[0054] Ar gas is used as the discharge gas. The discharge power is: first deposition source 61: 0.5 W / cm 2 ~10W / cm 2 , 2nd deposition source 62:0.5W / cm 2 ~10W / cm 2The discharge power may be DC power, pulse DC power, or AC power (RF, VHF, etc.). The film formation pressure is 0.2 Pa to 3.0 Pa. The distance (T / S) between the substrate and the film formation source is 9 cm to 30 cm. The target length (length of the target in the X-axis direction) is 180 cm to 350 cm. The scanning speed is 200 cm / min to 1000 cm / min. The film formation speed on the substrate 91 by the first film formation source 61 or the second film formation source 62 is 10 nm / sec to 100 nm / sec. The film formation temperature is 25° C. to 80° C. The film formation speed may be set to the same film formation speed in the first film formation source 61 and the second film formation source 62, or may be set to different film formation speeds.

[0055] When forming the cathode layer 41 in which the second component and the first component are alternately laminated, the film formation source 60 is controlled as follows. For example, the shutter 67 of the first film formation source 61 is closed or power is not supplied to the first film formation source 61, and the shutter 68 of the second film formation source 62 is opened, and a predetermined power is supplied to the second film formation source 62. Then, while moving the electron injection layer 31 and the film formation source 60 relative to each other, sputtering particles 62s are emitted from the second film formation source 62 to form a film of the second component on the electron injection layer 31. At this time, the thickness of the second component is adjusted by controlling the power input to the second film formation source 62 or the scanning speed.

[0056] Next, with the shutter 68 of the second film formation source 62 in a closed state or without supplying power to the second film formation source 62, and with the shutter 67 of the first film formation source 61 in an open state, a predetermined power is supplied to the first film formation source 61. Then, while moving the electron injection layer 31 and the film formation source 60 relative to each other, sputtering particles 61s are emitted from the first film formation source 61 to form a film of the first component on the electron injection layer 31. At this time, the thickness of the first component is adjusted by controlling the power input to the first film formation source 61 or the scanning speed.

[0057] By alternately repeating film formation by the second film formation source 62 and film formation by the first film formation source 61, the cathode layer 41 in which the second component and the first component are alternately laminated is formed on the electron injection layer 31. When forming the cathode layer 41 made of the first component, a sputtering layer, i.e., the cathode layer 41, may be formed on the substrate 90 using only the first film formation source 61.

[0058] In the organic light-emitting element 1, in order to lower the energy barrier against electrons at the interface between the electron transport layer 21 and the electron injection layer 31, a material containing at least one of an alkali metal, an alkaline earth metal, an alkali metal fluoride, an alkaline earth metal fluoride, and a lanthanoid is used as the material for the electron injection layer 31.

[0059] In the organic light-emitting element 1, an extremely thin metal or alloy layer having a thickness of more than 10 nm and not more than 20 nm, preferably 15 nm or more and not more than 20 nm, is used as the cathode layer 41. This increases the light transmittance of the cathode layer 41, and improves the light transmittance of the emitted light emitted from the cathode layer 41.

[0060] Furthermore, the cathode layer 41 contains a second component, such as Mg, which has a work function smaller than that of Ag or Al. In this case, more carriers (electrons) can be injected into the light-emitting layer 10 included in the organic light-emitting device 1 compared to a cathode layer made of Ag alone. As a result, the luminance of the organic light-emitting device 1 is further increased. For example, by forming the cathode layer 41 so that the concentration of the second component is relatively higher than the concentration of the first component on the electron injection layer 31 side, the effect of injecting carriers into the light-emitting layer 10 is further promoted.

[0061] In addition, in this embodiment, the cathode layer 41 is formed by a sputtering method, not by a vapor deposition method using a crucible. This suppresses the migration effect of the cathode layer 41 due to radiant heat that may occur in the vapor deposition method, and the cathode layer 41 is less likely to become island-shaped. Therefore, even if the cathode layer 41 is very thin, it becomes a flat continuous layer with low resistance.

[0062] For example, when comparing an Ag evaporated film with a thickness of 20 nm and an Ag sputtered film with a thickness of 20 nm, it has been found that the sheet resistance of the Ag evaporated film is 3.0 Ω / sq and the specific resistance is 6.0 μΩ·cm, while the sheet resistance of the Ag sputtered film is 2.2 Ω / sq and the specific resistance is 4.4 μΩ·cm. The light transmittance at this time was 34% (550 nm) for both the Ag evaporated film and the Ag sputtered film. Furthermore, it has been found that if the thickness of the Ag sputtered film is 15 nm, the light transmittance increases to 48% (550 nm).

[0063] In particular, when the cathode layer 41 is composed of a first component and a second component, for example, the effect of agglomeration of the sputtering layer is suppressed by dissolving the second component (e.g., Mg) in the first component (e.g., Ag) during film formation.

[0064] In addition, in this embodiment, by employing a sputtering method, the organic layers (electron injection layer 31, electron transport layer 21, light-emitting layer 10, hole transport layer 22, and hole injection layer 32) underlying the cathode layer 41 are less susceptible to the effects of heat radiation from the crucible, and heat damage to the organic layers is suppressed. As a result, a highly reliable organic light-emitting device is provided.

[0065] In this embodiment, the first film formation source 61 and the second film formation source 62 are separated by a partition plate 65. Therefore, during film formation, the sputtering particles 61s emitted from the first film formation source 61 are unlikely to adhere to the target surface of the second film formation source 62, and the sputtering particles 62s emitted from the second film formation source 62 are unlikely to adhere to the target surface of the first film formation source 61.

[0066] As a result, during film formation, plasma discharge is stabilized on the target surfaces of the first film formation source 61 and the second film formation source 62, and the sputtering particles of the first film formation source 61 and the second film formation source 62 do not interfere with each other at each time, and the emission amount of each is stabilized. In addition, since the sputtering particles 61s are unlikely to adhere to the second film formation source 62, and the sputtering particles 62s are unlikely to adhere to the first film formation source 61, the concentration distribution shown in Figures 2(a) and (b) can be reliably formed.

[0067] In particular, alkali metals and the like contained in the electron injection layer 31 are easily oxidized by a small amount of oxygen, water, and the like. In this embodiment, the cathode layer 41 is not an oxygen-containing transparent conductive layer such as ITO, but a cathode layer 41 made of a metal layer or an alloy layer is formed on the electron injection layer 31. This makes the electron injection layer 31 less susceptible to oxidation, and suppresses its deterioration.

[0068] Fig. 5(a) is a graph showing the light transmittance (%) in the Ag sputtering layer, and Fig. 5(b) is a graph showing the light transmittance (%) in the AgMg sputtering layer, where the horizontal axis is the wavelength of transmitted light.

[0069] Here, a quartz plate was used as the substrate, and the following sputtering layers were formed on the quartz plate. Sample 1: Ag metal layer (10 nm) Sample 2: Ag metal layer (15 nm) Sample 3: Ag metal layer (20 nm) Sample 4: AgMg alloy layer (10 nm, Mg content in Ag is equivalent to 10 atomic %) Sample 5: AgMg alloy layer (15 nm, Mg content in Ag is equivalent to 10 atomic %) Sample 6: AgMg alloy layer (20 nm, Mg content in Ag is equivalent to 10 atomic %)

[0070] 5(a) and (b), it can be seen that the light transmittance of the Ag metal layer and the AgMg alloy layer increases by reducing the thickness, regardless of whether the Ag metal layer or the AgMg alloy layer is used. In addition, since samples 1 and 4 have the same thickness, samples 2 and 5 have the same thickness, and samples 3 and 6 have the same thickness, it can be seen that the light transmittance increases relatively by mixing Mg into Ag, even if the Ag metal layer and the AgMg alloy layer have the same thickness.

[0071] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-mentioned embodiments, and various modifications can be made. Each embodiment is not limited to an independent form, and can be combined as far as technically possible. [Explanation of symbols]

[0072] 1...Organic light-emitting element 10...Emitting layer 21...Electron transport layer 22...Hole transport layer 31...electron injection layer 32...Hole injection layer 41…Cathode layer 42...Anode layer 50...Laminate 60…Film formation source 61...First film formation source 61s…Sputtering particles 62…Second film formation source 62s…Sputtering particles 65…Partition plate 67, 68...Shutter 67...Magnetic mechanism 70...Movement mechanism 90...Substrate holder 91... Circuit board 95…Adhesion prevention plate 96…Aperture 100...Film deposition equipment

Claims

1. A top-emission organic light-emitting device, a light-emitting layer provided between the cathode layer and the anode layer; an electron injection layer provided between the cathode layer and the light emitting layer; a hole injection layer provided between the anode layer and the light emitting layer; an electron transport layer provided between the electron injection layer and the light emitting layer; a hole transport layer provided between the hole injection layer and the light emitting layer; Equipped with the cathode layer is a sputtering layer, and includes a first component including at least one of Ag and Al, and a second component including at least one of Mg, Li, and Ca, and has a thickness of more than 10 nm and not more than 20 nm; the first component and the second component are dissolved in a solid solution, and the second component is contained in the first component in an amount of 10 atomic % to 20 atomic %; a concentration of the second component on the electron injection layer side is relatively high compared to a concentration of the first component; The thickness of the electron injection layer is 5 nm or more and 10 nm or less. Organic light-emitting devices.

2. The organic light-emitting device according to claim 1 , The electron injection layer contains at least one of an alkali metal, an alkaline earth metal, a fluoride of an alkali metal, a fluoride of an alkaline earth metal, and a lanthanoid. Organic light-emitting devices.

3. A top-emission organic light-emitting device, a light-emitting layer provided between the cathode layer and the anode layer; an electron injection layer having a thickness of 5 nm to 10 nm and provided between the cathode layer and the light emitting layer; a hole injection layer provided between the anode layer and the light emitting layer; an electron transport layer provided between the electron injection layer and the light emitting layer; a hole transport layer provided between the hole injection layer and the light emitting layer; A method for forming a cathode layer on an electron injection layer included in an organic light-emitting device comprising: The cathode layer contains a first component containing at least one of Ag and Al, and a second component containing at least one of Mg, Li, and Ca, the first component and the second component are in a solid solution, the second component is contained in the first component at 10 atomic % to 20 atomic %, and has a thickness of more than 10 nm and not more than 20 nm, and the concentration of the second component is relatively high compared to the concentration of the first component on the electron injection layer side. The cathode layer is formed by sputtering on the electron injection layer. Film formation method.

4. The film forming method according to claim 3, preparing a first film formation source containing the first component and a second film formation source containing the second component as film formation sources; When forming the cathode layer containing a component of the first film formation source and a component of the second film formation source while the film formation source and the electron injection layer are opposed to each other in a first direction and the electron injection layer and the film formation source are moved relatively in a second direction intersecting the first direction, the first film formation source and the second film formation source are aligned in the second direction so that the second film formation source and the electron injection layer overlap each other before the first film formation source in the first direction, and film formation is performed. Film formation method.

5. A film formation apparatus for forming a cathode layer on an electron injection layer included in a top-emission type organic light-emitting device, comprising: a substrate provided with a laminate including an anode layer, a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and the electron injection layer having a thickness of 5 nm or more and 10 nm or less, stacked in this order, the electron injection layer being exposed toward a film formation source; and a substrate holder capable of supporting the substrate, the electron injection layer being exposed toward a film formation source; a deposition source facing the substrate holder in a first direction and including a first sputtering target containing at least one of Ag and Al, and a second sputtering target containing at least one of Mg, Li, and Ca; a moving mechanism for relatively moving the substrate and the film formation source in a second direction intersecting the first direction, the first component and the second component are in a solid solution, and the second component is contained in the first component at 10 atomic % to 20 atomic %; The cathode layer is formed on the electron injection layer side, in which the concentration of the second component is relatively high compared to the concentration of the first component. Film deposition equipment.

6. The film forming apparatus according to claim 5, A partition plate extending in the first direction is provided between the first sputtering target and the second sputtering target. Film deposition equipment.

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