JP2010277758A - Organic electroluminescent device and electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic electroluminescent device with improved emission efficiency and device lifetime, by realizing proper electron injection into a light-emitting material. <P>SOLUTION: A plurality of light-emitting elements 60 each having a substrate 10A, an anode 30 fitted to the substrate 10A, a cathode 50 opposed to the anode 30, and an organic light-emitting layer 46 arranged between the anode 30 and the cathode 50 are provided on the substrate 10A. The cathode 50 is provided with a first cathode layer 52 arranged in contact with the organic light-emitting layer 46; a second cathode layer 54 arranged opposite to the organic light-emitting layer 46 of the first cathode layer 52; and a third cathode layer 56, arranged in contact with the first cathode layer 52 between the first cathode layer 52 and the second cathode layer 54, a forming material of the third cathode layer 56 having a work function lower than those of the first cathode layer 52 and the second cathode layer 54. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an organic electroluminescence device and an electronic apparatus.

  With the diversification of information equipment, the need for flat display devices that consume less power and are lighter is increasing. As one of such flat display devices, an organic electroluminescence device (hereinafter referred to as “organic EL device”) having an organic light emitting layer is known.

  In order to cause the organic EL device to emit light satisfactorily and stably drive, it is known that the structure of the cathode for injecting electrons into the organic light emitting layer has a great influence. The quality of electron injection is mainly due to the large energy level difference between the cathode and the organic light emitting layer (energy barrier), and various cathode structures have been studied to improve the electron injection. ing.

  For example, in Patent Document 1, in order to improve the electron injection property from the cathode, a base metal electrode that is in contact with the organic light emitting layer and has a low work function that facilitates electron injection into the organic light emitting layer is used. A structure in which a metal having a large function is covered and laminated is proposed. In Patent Documents 2 and 3, methods for improving the electron injection property by devising the material of the electron injection layer disposed between the cathode and the light emitting layer are studied.

Japanese Patent No. 2760347 Japanese Patent Laid-Open No. 2003-347061 JP 2000-299189 A

  However, even in the organic EL device having the configuration described in the above-mentioned patent document, the improvement of the electron injection property is not sufficient, and therefore further improvement in the light emission efficiency and the element life is required.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide an organic electroluminescence device that realizes good electron injection into a light emitting material and has improved light emission efficiency and element lifetime. To do. It is another object to provide an electronic device including such an organic electroluminescence device.

  In order to solve the above-described problems, an organic electroluminescence device of the present invention includes a substrate, an anode provided on the substrate, a cathode facing the anode, and an organic material disposed between the anode and the cathode. A plurality of light emitting elements having a light emitting layer on the substrate, wherein the cathode is opposite to the first light emitting layer disposed in contact with the organic light emitting layer and the organic light emitting layer of the first cathode layer. A second cathode layer disposed on the side, and a third cathode layer disposed in contact with the first cathode layer between the first cathode layer and the second cathode layer, and The material for forming the cathode layer has a lower work function than the material for forming the first cathode layer and the second cathode layer.

  According to this configuration, the electron injection property from the first cathode layer to the organic light emitting layer is influenced by the third cathode layer, and the electron injection property of the third cathode layer having a work function lower than that of the first cathode layer is achieved. Get closer. Further, the electron injectability from the second cathode layer to the third cathode layer is good due to the relative work function of both. Therefore, it can be set as the cathode from which favorable electron injection property is obtained. The electron injecting property of the cathode having such a structure can be determined by selecting, for example, a material for forming the first cathode layer, a layer thickness of the first cathode layer, and / or a material for forming the third cathode layer, and a layer for the third cathode layer. Can be controlled by thickness. Therefore, it is possible to easily form a cathode having good electron injection properties corresponding to the organic light emitting layer, and to provide an organic electroluminescence device with improved light emission efficiency.

In the present invention, the cathode has a work function between the second cathode layer and the third cathode layer that is lower than that of the second cathode layer and higher than that of the third cathode layer. It is desirable to have the 4th cathode layer which uses the material which has as a forming material.
Since the material for forming the fourth cathode layer has a higher work function and lower reactivity than the material for forming the third cathode layer provided in the lower layer, the fourth cathode layer protects the third cathode layer, so that Deterioration of the three cathode layers can be suppressed. Further, by providing the fourth cathode layer, it is possible to relax the energy barrier due to the work function difference between the forming materials of the second cathode layer and the third cathode layer, and to perform good electron injection. Therefore, an organic electroluminescence device having good display characteristics and a long life can be obtained.

In the present invention, the first cathode layer and the fourth cathode layer are preferably made of the same material.
According to this configuration, since a layer structure is formed using a common forming material, it is possible to share a manufacturing apparatus and a process, and an organic electroluminescence device having good display characteristics can be easily obtained. .

In the present invention, the first cathode layer is preferably made of an alkali metal, an alkaline earth metal having a work function of 2.9 eV or less, or a metal salt thereof.
According to this structure, it can be set as the cathode which implement | achieves favorable electron injection property with respect to an organic light emitting layer.

In the present invention, the anode has light transparency, the second cathode layer has transflective properties, and a light reflection layer is disposed on the opposite side of the organic light emitting layer across the anode. It is desirable that an optical resonator structure for resonating light emitted from the organic light emitting layer is formed between the light reflecting layer and the cathode.
According to this configuration, by configuring an optical resonant structure that resonates light emitted from the organic light emitting layer, each organic EL element has a resonant wavelength corresponding to the optical distance between the light reflecting layer and the cathode. Only light that satisfies the condition is amplified and extracted. For example, an organic EL device capable of full color display can be provided by forming organic EL elements having resonance wavelengths corresponding to red (R), green (G), and blue (B) colors.

An electronic apparatus according to the present invention includes the above-described organic electroluminescence device.
According to this configuration, it is possible to provide an electronic device having a light emitting efficiency and a long-life organic EL device and having excellent reliability.

1 is a cross-sectional view schematically showing an organic EL device according to a first embodiment of the present invention. It is sectional drawing which shows typically the modification of the organic electroluminescent apparatus of 1st Embodiment. It is sectional drawing which shows typically the organic electroluminescent apparatus which concerns on 2nd Embodiment of this invention. It is sectional drawing which shows typically the modification of the organic electroluminescent apparatus of 2nd Embodiment. It is a perspective view which shows an example of the electronic device which concerns on this invention.

[First Embodiment]
The organic EL device 1 according to the first embodiment of the present invention will be described below with reference to FIGS. In all the drawings below, the film thicknesses and dimensional ratios of the constituent elements are appropriately changed in order to make the drawings easy to see.

  Further, as the value of the work function of the metal in the description of the present invention, values known in the literature can be used (for example, Herbert B. Michaelson, “The work function of the elements and its periodicity”, Journal of Applied Physics, November 1977, Vol.48, No.11, p.4729-p.4733).

  FIG. 1 is a cross-sectional view schematically showing the organic EL device 1. As shown in the figure, the organic EL device 1 is formed on a substrate 10A including a substrate body 10 and an element layer 11 including a driving element (not shown) formed on the substrate body 10 and the substrate 10A. A pixel electrode (anode) 30 having optical transparency, a pixel partition layer 12 having an opening that overlaps the pixel electrode 30 in a plane, and a common partition layer 14 formed on the pixel partition layer 12 are provided. ing.

  In a region surrounded by the common partition layer 14, a light emitting unit 40 is formed in contact with the side wall of the common partition layer 14, and a cathode 50 covering the entire upper surface of the light emitting unit 40 is formed. The pixel electrode 30, the light emitting unit 40, and the cathode 50 form an organic EL element (light emitting element) 60. The cathode 50 of the present invention is composed of a plurality of layers as will be described later.

  The light emitting unit 40 includes a hole injection layer 42 that facilitates injection of holes from the pixel electrode 30, a hole transport layer 44 that promotes movement of holes from the hole injection layer 42, and an organic light emitting layer 46. And are stacked on the pixel electrode 30 in this order.

  The cathode 50 includes a first cathode layer 52 that covers the top surface and side walls of the common barrier layer 14 and covers the entire upper surface of the organic light emitting layer 46; a second cathode layer 54 that covers the entire surface of the first cathode layer 52; Furthermore, a third cathode layer 56 provided between the first cathode layer 52 and the second cathode layer 54 and covering the entire surface of the first cathode layer 52 is provided.

  The organic EL device 1 of the present embodiment employs a bottom emission method in which light L generated in the organic light emitting layer 46 is emitted to the outside through the pixel electrode 30. Hereinafter, each component will be described in order.

  The substrate body 10 can be a transparent substrate having optical transparency. As such a transparent substrate, for example, inorganic substances such as glass, quartz glass, and silicon nitride, and organic polymers (resins) such as acrylic resins and polycarbonate resins can be used. In addition, a composite material formed by laminating or mixing the above materials can be used as long as it has optical transparency. In the present embodiment, glass is used as the material of the substrate body 10.

  The element layer 11 includes various wirings and driving elements for driving the organic EL device 1, and an inorganic or organic insulating film. Various wirings and drive elements can be appropriately formed by patterning by photolithography and then etching, and the insulating film can be appropriately formed by a generally known method such as vapor deposition or sputtering.

  A pixel electrode 30 is formed on the element layer 11. As a material for forming the pixel electrode 30, a material having light transmittance and a work function of 5 eV or more can be used. Such a material is preferable as a material for forming the pixel electrode 30 because of its high hole injection effect. Examples of such a material include metal oxides such as ITO (Indium Tin Oxide). In this embodiment, ITO is used.

  Further, the pixel partition layer 12 is formed on the element layer 11 so that a part of the pixel electrode 30 runs over the end portion of the pixel electrode 30. The pixel partition layer 12 includes an opening corresponding to the pixel electrode 30, and the pixel electrode 30 is exposed in the opening. The pixel partition layer 12 is made of an inorganic insulating material such as silicon oxide or silicon nitride, and can be formed by a known method such as etching through a mask corresponding to the position of the opening.

  On the pixel partition layer 12, a common partition layer 14 is formed so as to surround the periphery of the pixel electrode 30. The common partition wall layer 14 is formed in a forward tapered shape in cross section. For this reason, the space surrounded by the common partition wall layer 14 is wider at the top than at the bottom. The common partition wall layer 14 is formed of, for example, a photocurable acrylic resin or polyimide resin.

  A surface exposed in the bottom surface of the region surrounded by the common partition wall layer 14 (here, part of the pixel electrode 30 and the pixel partition wall layer 12) is in contact with the side wall of the common partition wall layer 14 so as to be positive from the pixel electrode 30. A hole injection layer 42 as a charge transfer layer that facilitates hole injection is formed. As a material for forming the hole injection layer 42, a generally known material can be used. In this embodiment, PEDOT / PSS is used.

  On the hole injection layer 42, a hole transport layer 44 is formed in contact with the side wall of the common partition wall layer 14, and an organic light emitting layer 46 is further formed. As a material for forming these layers, generally known materials can be used.

  For example, as a material for forming the hole transport layer 44, ADS259BE (trade name, manufactured by American Dye Source) represented by the following chemical formula 1 can be used. In addition, as a material for forming the organic light emitting layer 46, a green light emitting polymer material ADS109GE (manufactured by the company, trade name) represented by the chemical formula 2, a red light emitting polymer material ADS111RE (manufactured by the company, trade name) represented by the chemical formula 3, A blue light-emitting polymer material ADS136BE (trade name, manufactured by the same company) represented by Chemical Formula 4 can be used.

(Configuration of cathode)
A cathode 50 is formed on the entire surface of the organic light emitting layer 46 so as to cover the top surface and side walls of the common partition wall layer 14. As described above, the cathode 50 of the present embodiment has a structure in which the first cathode layer 52, the third cathode layer 56, and the second cathode layer 54 are laminated in this order.

  These cathode layer forming materials have a relative magnitude relationship in work function, and the second cathode layer 54 forming material is based on the first cathode layer 52 forming material. The material forming the layer 52 has a higher work function, and the material forming the third cathode layer 56 has a lower work function than the material forming the first cathode layer 52.

  The first cathode layer 52 can be formed by vacuum deposition using an alkali metal or an alkaline earth metal having a work function of 2.9 eV or less and an inorganic salt containing the metal as a forming material. , Cs, Ca, Sr, Ba. When such a material is used, it becomes easy to realize a good electron injection property to the organic light emitting layer 46. In this embodiment, Ca is used as a material. The film thickness of the first cathode layer 52 is preferably 5 nm or less in consideration of ensuring transparency and realizing good electron injection properties. The thickness of the first cathode layer 52 of this embodiment is 5 nm.

A third cathode layer 56 is formed on the first cathode layer 52 so as to cover the entire surface of the first cathode layer 52. The third cathode layer 56 is formed by vacuum deposition using a metal having a work function lower than that of the material for forming the first cathode layer 52 and an inorganic salt containing such a metal as the material. In this embodiment, CsCO ₃ is used as a material. It is desirable that the third cathode layer 56 has a film thickness that does not have light reflectivity. The third cathode layer 56 of this embodiment is formed to a thickness of 0.5 nm.

  On the third cathode layer 56, a second cathode layer 54 made of Al is formed so as to cover the entire surface of the third cathode layer 56. The second cathode layer 52 of the present embodiment is formed to a thickness of 200 nm and has sufficient light reflectivity and conductivity. In addition, since Al, which is a material for forming the second cathode layer 54, is stable against moisture and oxygen, when moisture / oxygen enters from outside the apparatus, the third cathode layer 56 or It also functions as a protective layer that protects the first cathode layer 52 and protects it from deterioration. The second cathode layer 54 is connected to a cathode contact portion connected to a cathode take-out terminal (not shown).

In the cathode 50 having such a configuration, the following phenomenon occurs.
First, as a result of the study conducted by the inventors, the first cathode layer 52 made of Ca is not formed, and the third cathode layer 56 made of CsCO ₃ is formed so as to be in contact with the organic light emitting layer 46. It has been found that the electron injecting property is improved due to the low work function of CsCO ₃ , but the electron injecting property is too high and the carrier balance in the light emitting element 21 is lost, and the light emitting efficiency is lowered.

  Here, the electron injection property is too high, and “carrier balance is lost” means that the amount of electrons injected from the cathode is larger than the amount of holes injected from the anode. On the other hand, it means that the amount of holes and electrons bonded in the organic light emitting layer 46 (that is, the light emission amount) is small. Excess electrons are not used for light emission, and only current flows. Then, the rate of the amount of electrons contributing to light emission with respect to the input power becomes small, and it becomes impossible to emit light efficiently with respect to the input power. That is, the light emission efficiency is lowered.

  In such a case, as described above, the first cathode layer 52 having a work function higher than that of the third cathode layer 56 is formed between the organic light emitting layer 46 and the third cathode layer 56, so that the third The high electron injection property from the cathode layer 56 to the organic light emitting layer 46 is suppressed, and the effect of bringing it close to the electron injection property due to the first cathode layer 52 occurs. That is, the electron injecting property to the organic light emitting layer 46 is not only caused by the work function of the first cathode layer 52 in contact with the organic light emitting layer 46 but is also affected by the third cathode layer 56.

In the case where the cathode 50 in contact with the organic light emitting layer 46 has a laminated structure of the above-described first cathode layer 52 made of Ca and the second cathode layer 54 made of Al. In contrast, the cathode 50 of this embodiment in which the third cathode layer 56 made of CsCO ₃ is formed between the first cathode layer 52 and the second cathode layer 54 has better electron injection properties and light emission efficiency. It was confirmed that it was good.

  From this result, it can be said that the first cathode layer 52 suppresses the high electron injection property from the third cathode layer 56 to the organic light emitting layer 46, and the first cathode layer 52 and the second cathode layer 54 If the third cathode layer 56 using a material having a lower work function than the material for forming the first cathode layer 52 is disposed therebetween, it can be said that the electron injection property of the first cathode layer 52 is improved. In any case, since each cathode layer constituting the cathode 50 is formed by using the work function forming material as described above, a good electron injection property can be realized.

  The electron injecting property is controlled by the selection of the material for forming the first cathode layer 52, the layer thickness of the first cathode layer 52, the material for forming the third cathode layer 56, and the layer thickness of the third cathode layer 56. be able to. Therefore, it is possible to easily form the cathode 50 having a good electron injection property corresponding to the forming material of the organic light emitting layer 46 to be used.

An inorganic film such as SiO _x N _y (not shown) is formed on the cathode 50, and a glass substrate is bonded on the inorganic film via an epoxy resin. Good.

Moreover, the sealing can member which provided the recessed part in the glass substrate and arrange | positioned the desiccant is arrange | positioned so that the surface by the side of the recessed part of a glass substrate may oppose the cathode 50, and this glass substrate and board | substrate 10A may overlap | superpose planarly It is good also as what has what is called a can sealing structure which adhere | attaches the periphery of this with an epoxy resin etc.
The organic EL device 1 of the present embodiment has the above configuration.

  According to the organic EL device 1 having the above-described configuration, the organic EL device 1 having improved light emission efficiency and element life can be obtained because it has a cathode exhibiting good electron injection properties.

  In the present embodiment, the cathode 50 has a configuration in which three types of cathode layers are stacked. However, the present invention is not limited to this. FIG. 2 is a cross-sectional view schematically showing an organic EL device 2 which is a modification of the present embodiment, and corresponds to FIG. In the organic EL device 2, a fourth cathode layer 58 is formed between the third cathode layer 56 and the second cathode layer 54.

  The work function of the material forming the fourth cathode layer 58 is higher than that of the third cathode layer 56 and lower than that of the second cathode layer 54. In the organic EL device 2 of the present embodiment, the material for forming the fourth cathode layer 58 is Ca as in the first cathode layer 52. If a common forming material is used in this way, the types of necessary raw materials are reduced, which is preferable because the process load is reduced.

  Since the material for forming the fourth cathode layer 58 has a higher work function and lower reactivity than the material for forming the third cathode layer 56 provided in the lower layer, the fourth cathode layer 58 protects the third cathode layer 56. As a result, the deterioration of the third cathode layer 56 can be suppressed. Further, by providing the fourth cathode layer 58, an energy barrier caused by a work function difference between the forming materials of the third cathode layer 56 and the second cathode layer 54 can be reduced, and good electron injection can be performed.

  In the present embodiment, an alkali metal or an alkaline earth metal having a work function of 2.9 eV or less and a metal salt thereof are used as a material for forming the first cathode layer 52. However, the present invention is not limited to this. As a material for forming the first cathode layer 52, when a material with a low work function is used, the film thickness is relatively thick. When a material with a high work function is used, the film thickness is relatively thin. Other metal materials can be used. For example, when Al (work function: 4.28) is used as a material for forming the first cathode layer 52, the work function is higher than that of Ca (work function: 2.87) used in the present embodiment. It is preferable that the thickness is 1 nm and the thickness is relatively thin.

  In the present embodiment, the material for forming the organic light emitting layer 46 is a polymer compound. However, the present invention is not limited to this, and the same effect can be obtained even when a low molecular weight organic light emitting material is used. can get.

[Second Embodiment]
3-4 is explanatory drawing of the organic EL apparatus 2 which concerns on 2nd Embodiment of this invention. The organic EL device 2 of the present embodiment is partially in common with the organic EL device 1 of the first embodiment. The difference is that a top emission method in which light generated in the organic light emitting layer 46 is emitted to the cathode 50 side is employed. Therefore, in this embodiment, the same code | symbol is attached | subjected about the component which is common in 1st Embodiment, and detailed description is abbreviate | omitted.

  FIG. 3 is a cross-sectional view schematically showing the organic EL device 2. As shown in the figure, a reflective layer (light reflective layer) 20 is formed on the substrate body 10 in the element layer 11 so as to overlap the pixel electrode 30 in a plan view. The reflective layer is made of an AlNd alloy, and is formed by a generally known method such as mask patterning. In the present embodiment, the reflective layer 20 is formed on the substrate body 10, but may be formed in the element layer 11 or may be formed on the surface of the element layer 11.

  A second cathode layer 54 is formed on the third cathode layer 56 so as to cover the entire surface of the third cathode layer 56. The second cathode layer 54 is an alloy layer formed by vacuum co-evaporation using a metal material having a work function of 3.5 eV or more and less than 4.2 eV and a metal material having a work function of 4.2 eV or more. is there. Examples of the former metal material include Mg, Sc, Mn, In, Zr, and As, and examples of the latter metal material include Al, Ag, Cu, Ni, and Au. In this embodiment, Mg and Ag are used as the metal material.

  Since the second cathode layer 54 is an alloy layer of Mg and Ag, it becomes a cathode layer having both a work function lower than that of Ag alone and high stability against moisture and oxygen derived from the properties of Ag. ing. In this embodiment, the co-evaporation ratio of Mg and Ag is 10: 1 by volume ratio.

  The second cathode layer 54 plays a role as a resonance layer (semi-transmissive reflection layer), and the film thickness is preferably 20 nm or less in order to achieve both light transmission and light reflection. In addition, in consideration of ensuring good surface direction conductivity (low sheet resistance value), it is preferable to provide a film thickness of, for example, about 5 nm or more. The second cathode layer 54 of this embodiment has a thickness of 15 nm.

  The organic EL device 2 constitutes an optical resonance structure in which light is resonated between the second cathode layer 54 and the reflection layer 20, and the organic EL element 60 includes a reflection layer 20 and a second cathode layer 54. Only light satisfying the resonance wavelength condition corresponding to the optical distance between them is amplified and extracted. For example, in an organic EL device having a plurality of organic EL elements 60, full-color display can be achieved by forming organic EL elements having resonance wavelengths corresponding to red (R), green (G), and blue (B) colors. A possible organic EL device can be provided.

  The cathode 50 is preferably provided with a solid sealing structure. The organic EL device 2 of the present embodiment has the above configuration.

  According to the organic EL device 2 having the above-described configuration, a top emission type organic EL device having a good optical resonance structure can be obtained, and a high-quality organic EL with improved color purity of emitted light. It can be a device.

  In the present embodiment, the cathode 50 has a structure in which three types of cathode layers are laminated. However, the present invention is not limited to this, and as shown in FIG. The organic EL device 4 in which the fourth cathode layer 58 is formed between the third cathode layer 56 and the second cathode layer 54 can be obtained.

[Electronics]
Next, an embodiment of the electronic device of the present invention will be described. FIG. 5 is a perspective view showing an example of an electronic apparatus using the organic EL device of the present invention. A cellular phone (electronic device) 1300 illustrated in FIG. 5 includes the organic EL device of the present invention as a small-sized display unit 1301, and includes a plurality of operation buttons 1302, an earpiece 1303, and a mouthpiece 1304. Yes. Thereby, the mobile phone 1300 provided with the display part without the light emission nonuniformity comprised by the organic electroluminescent apparatus of this invention can be provided.

  The organic EL device of each of the above embodiments is not limited to the mobile phone, but is an electronic book, a projector, a personal computer, a digital still camera, a television receiver, a viewfinder type or a monitor direct view type video tape recorder, and a car navigation device. , Pagers, electronic notebooks, calculators, word processors, workstations, videophones, POS terminals, devices equipped with touch panels, and the like. With this configuration, an electronic device including a display portion with high display quality and excellent reliability can be provided.

  Furthermore, the organic EL device of each of the above embodiments can be used as a line head, and can be suitably used as an image forming apparatus (optical printer) including the line head as a light source. If it does in this way, it can be set as the optical printer excellent in reliability without light emission nonuniformity.

  The preferred embodiments of the present invention have been described above with reference to the accompanying drawings, but it goes without saying that the present invention is not limited to such examples. Various shapes, combinations, and the like of the constituent members shown in the above-described examples are examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.

  DESCRIPTION OF SYMBOLS 1-4 ... Organic electroluminescent apparatus, 10A ... Board | substrate, 20 ... Light reflection layer, 30 ... Pixel electrode (anode), 40 ... Light emission part, 46 ... Organic light emitting layer, 52 ... 1st cathode layer, 50 ... Cathode, 54 ... 2nd cathode layer, 56 ... 3rd cathode layer, 58 ... 4th cathode layer, 60 ... Organic EL element (light emitting element), 1300 ... Mobile phone (electronic device)

Claims (6)

A substrate,
A plurality of light emitting elements on the substrate, each including an anode provided on the substrate, a cathode facing the anode, and an organic light emitting layer disposed between the anode and the cathode,
The cathode comprises a first cathode layer disposed in contact with the organic light emitting layer;
A second cathode layer disposed on the opposite side of the first cathode layer from the organic light emitting layer;
A third cathode layer disposed in contact with the first cathode layer between the first cathode layer and the second cathode layer;
The material for forming the third cathode layer has a lower work function than the material for forming the first cathode layer and the second cathode layer.   The cathode is formed of a material having a work function lower than that of the second cathode layer and higher than that of the third cathode layer, between the second cathode layer and the third cathode layer. The organic electroluminescence device according to claim 1, further comprising a fourth cathode layer as a material.   The organic electroluminescence device according to claim 2, wherein the first cathode layer and the fourth cathode layer are made of the same material.   4. The first cathode layer according to claim 1, wherein the first cathode layer is made of an alkali metal, an alkaline earth metal having a work function of 2.9 eV or less, or a metal salt thereof. 5. Organic electroluminescence device.   The anode has light transmissivity, the second cathode layer has transflective properties, a light reflecting layer is disposed on the opposite side of the organic light emitting layer across the anode, and the light reflecting layer 5. The organic electroluminescence device according to claim 1, wherein an optical resonator structure that resonates light emitted from the organic light emitting layer is formed between the cathode and the cathode. .   An electronic apparatus comprising the organic electroluminescence device according to any one of claims 1 to 5.

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