JP2015191978A - Light emitting device and electronic apparatus - Google Patents

Abstract

In a light emitting device including a plurality of light emitting elements having different light emission colors, a light emitting device and an electronic device capable of increasing the light emission efficiency of each light emitting element and efficiently manufacturing the light emitting device are provided. A light-emitting device 100 according to the present invention includes an anode 3R, 3G, and 3B, a cathode 10, and a hole transport layer 5R, 5G, and 5B provided between the anode 3R, 3G, and 3B and the cathode 10. And between the hole transport layers 5R and 5G and the cathode 10 between the hole transport layers 5R and 5G, and between the hole transport layers 5R and 6G and the cathode 10 A hole transport layer 7 that is in contact with the hole transport layer 5B and is in contact with the light emitting functional layers 6R and 6G between the cathode 10 and the light emitting functional layers 6R and 6G; The thickness of the light emitting functional layer 6 </ b> B provided in contact with the hole transport layer 7 and the hole transport layer 7 is 2 nm or less. [Selection] Figure 1

Description

  The present invention relates to a light emitting device and an electronic apparatus.

  An organic electroluminescence element (so-called organic EL element) is a light emitting element having a structure in which at least one light emitting organic layer (light emitting layer) is interposed between an anode and a cathode. In such a light emitting device, by applying an electric field between the cathode and the anode, electrons are injected into the light emitting layer from the cathode side and holes are injected from the anode side, and electrons and holes are injected into the light emitting layer. Recombination generates excitons, and when the excitons return to the ground state, the energy is emitted as light.

  For example, when a display device is configured using such light emitting elements, red light emitting elements, green light emitting elements, and blue light emitting elements are used in combination (for example, see Patent Document 1). The light-emitting device described in Patent Document 1 includes a light-emitting element having a red light-emitting layer, a light-emitting element having a green light-emitting layer, and a light-emitting element having a blue light-emitting layer, and the blue light-emitting layer serves as a red light-emitting layer as a common layer. It is also formed on the green light emitting layer. In such a light emitting device, a red light emitting layer and a green light emitting layer are formed by a liquid phase process such as an ink jet method, and a blue light emitting layer and a layer on the cathode side of the blue light emitting layer are used as a common layer by a vapor phase process such as an evaporation method. By forming, efficient production becomes possible.

  However, in the light emitting device described in Patent Document 1, in the blue light emitting element, the blue light emitting layer formed by the vapor phase process is directly provided on the hole transport layer formed by the liquid phase process. There is a problem in that the carrier transportability at the interface of this layer is poor and the luminous efficiency is lowered.

JP 2011-29666 A

  An object of the present invention is to provide a light-emitting device including a plurality of light-emitting elements (first light-emitting element and second light-emitting element) having different emission colors, and to increase the light-emitting efficiency of each light-emitting element and efficiently manufacture the light-emitting device. It is another object of the present invention to provide a light-emitting device that can be used, and to provide an electronic device including the light-emitting device.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

[Application Example 1]
The light emitting device of the present invention includes a first anode, a common cathode, a first hole transport layer provided between the first anode and the common cathode, and the first hole transport layer and the common. A first light emitting functional layer provided between the cathode and the first hole transport layer in contact with the first hole transport layer;
A second anode, the common cathode, a second hole transport layer provided between the second anode and the common cathode, and a gap between the second hole transport layer and the common cathode. A common hole transport layer provided in contact with the second hole transport layer; and a second light emission provided in contact with the common hole transport layer between the common hole transport layer and the common cathode. A second light emitting element having a functional layer,
The common hole transport layer is provided in contact with the first light emitting functional layer between the common cathode and the first light emitting functional layer,
The common hole transport layer has a thickness of 2 nm or less.

  According to such a light emitting device, the first hole transport layer, the first light emitting functional layer, and the second hole transport layer are individually formed for each element using a liquid phase process, and a gas phase process is used. Thus, the common hole transport layer and the second light emitting functional layer can be formed in common for the two elements. Therefore, the first light emitting element and the second light emitting element can be efficiently manufactured.

  When the first light-emitting element and the second light-emitting element are formed as described above, the second light-emitting element is formed between the second hole transport layer and the second light-emitting functional layer by the same vapor phase process as that of the second light-emitting functional layer. Compared to the case where the second hole transport layer and the second light emitting functional layer having different manufacturing methods are directly laminated, the second hole transport layer and the second hole transport layer can be provided. It is possible to reduce an electrical barrier related to carrier movement between the two light emitting functional layers. Therefore, carriers (holes) are smoothly transported to the second light emitting functional layer, and the light emission efficiency can be improved.

  On the other hand, in the first light emitting element, since the common hole transport layer provided between the first light emitting functional layer and the second light emitting functional layer is extremely thin, the second light emitting functional layer to the first light emitting functional layer. Carriers (electrons) can be delivered to the layer. Therefore, the first light emitting functional layer can selectively emit light without causing the second light emitting functional layer to emit light in the first light emitting element.

  Moreover, since the thickness of the common hole transport layer is extremely thin, an increase in driving voltage of the first light emitting element and the second light emitting element due to the provision of the common hole transport layer can be suppressed.

  As described above, in a light-emitting device including a plurality of light-emitting elements (first light-emitting element and second light-emitting element) having different emission colors, the light-emitting device is efficiently manufactured while increasing the light-emitting efficiency of each light-emitting element. can do.

[Application Example 2]
In the light emitting device of the present invention, the first hole transport layer, the first light emitting functional layer, and the second hole transport layer are each formed using a liquid phase process,
The common hole transport layer and the second light emitting functional layer are each preferably formed using a vapor phase process.
Thereby, a 1st light emitting element and a 2nd light emitting element can be manufactured efficiently.

[Application Example 3]
In the light emitting device of the present invention, the first hole transport layer is configured using a polymer hole transport material,
The second hole transport layer and the common hole transport layer are each preferably configured using a low-molecular hole transport material.

  Thereby, the 1st positive hole transport layer which has a high dimensional accuracy can be efficiently formed using a liquid phase process. In addition, by forming both the first light emitting functional layer and the first hole transporting layer using a liquid phase process, carriers (holes) are smoothly transported from the first hole transporting layer to the first light emitting functional layer. be able to.

  In addition, the second hole transport layer and the common hole transport layer having high dimensional accuracy can be efficiently formed using a vapor phase process. In particular, by forming the common hole transport layer using a vapor phase process, an extremely thin common hole transport layer can be formed with high accuracy (with good controllability). Moreover, even if the second hole transport layer and the common hole transport layer are formed by different manufacturing methods, since the hole transport materials constituting them are both low-molecular, they are common from the second hole transport layer. Carriers (holes) can be smoothly transported to the hole transport layer.

[Application Example 4]
In the light emitting device of the present invention, it is preferable that the second hole transport layer includes a material having the same or similar characteristics as the constituent material of the common hole transport layer.

  Thereby, carriers (holes) can be smoothly transported from the second hole transport layer to the second light emitting functional layer through the common hole transport layer.

[Application Example 5]
In the light emitting device of the present invention, the constituent material of the common hole transport layer preferably has an electron blocking property.

  Thereby, in the second light emitting element, the second light emitting functional layer can efficiently emit light by utilizing the electron blocking property of the common hole transport layer. On the other hand, if the electron blocking property of the common hole transport layer is too high in the first light emitting element, light emission by the first light emitting functional layer does not occur or the light emission efficiency is remarkably reduced. Therefore, in this case, it is extremely useful to make the thickness of the common hole transport layer extremely thin so that the electron blocking property of the common hole transport layer in the first light emitting element is lowered.

[Application Example 6]
In the light emitting device of the present invention, the constituent material of the first light emitting functional layer is preferably composed of a low molecular material as a main material.

  Thereby, the luminous efficiency of a 1st light emission functional layer can be improved, and the fall of the luminous efficiency of the 1st light emitting element by providing a common hole transport layer can be compensated. As a result, the light emission balance between the first light emitting element and the second light emitting element can be made excellent.

[Application Example 7]
In the light emitting device of the present invention, the common hole transport layer preferably has a thickness of 1 nm or less.

  Thereby, in the first light emitting element, the electron blocking property of the common hole transport layer can be lowered, and carriers (electrons) can be more efficiently transferred from the second light emitting functional layer to the first light emitting functional layer. .

[Application Example 8]
In the light emitting device of the present invention, a third anode, the common cathode, the third anode, a third hole transport layer provided between the common cathode, and the third hole transport layer, A third light emitting element having a third light emitting functional layer provided in contact with the third hole transport layer between the common cathode,
The common hole transport layer is also in contact with the third light emitting functional layer,
The first light emitting element, the second light emitting element, and the third light emitting element preferably have different emission colors.

  Thereby, in a light-emitting device including the first light-emitting element, the second light-emitting element, and the third light-emitting element having different light emission colors, the light-emitting device can be efficiently manufactured while increasing the light-emitting efficiency of each light-emitting element.

[Application Example 9]
In the light emitting device of the present invention, the emission color of the first light emitting element is red,
The emission color of the second light emitting element is blue,
The emission color of the third light emitting element is preferably green.

  Thereby, in a light-emitting device including a red light-emitting element, a green light-emitting element, and a blue light-emitting element, the light-emitting device can be efficiently manufactured while increasing the light-emitting efficiency of each light-emitting element. That is, a light emitting device capable of full color display with high efficiency and low cost can be provided.

[Application Example 10]
An electronic apparatus according to the present invention includes the light emitting device according to the present invention.

  According to such an electronic device, since a light-emitting device with low cost and high efficiency is provided, cost reduction and power consumption reduction can be achieved.

It is sectional drawing which shows the light-emitting device (display apparatus) which concerns on embodiment of this invention. It is a figure for demonstrating the manufacturing method of the light-emitting device shown in FIG. It is a figure for demonstrating the manufacturing method of the light-emitting device shown in FIG. It is a figure for demonstrating the manufacturing method of the light-emitting device shown in FIG. 1 is a perspective view illustrating a configuration of a mobile (or notebook) personal computer that is an example of an electronic apparatus of the present invention. It is a perspective view which shows the structure of the mobile telephone (PHS is also included) which is an example of the electronic device of this invention. 1 is a perspective view illustrating a configuration of a digital still camera that is an example of an electronic apparatus of the present invention. (A) is the graph which shows the lifetime of the light emitting element of G pixel in Examples 1, 9, 10 and Comparative Examples 1 and 2, (b) is the B pixel of Examples 1, 10 and Comparative Examples 1 and 2. It is a graph which shows the lifetime of a light emitting element.

  Hereinafter, a light emitting device and an electronic apparatus according to the present invention will be described based on preferred embodiments shown in the drawings. In each drawing, the scale of each part is appropriately changed for convenience of explanation, and the illustrated configuration does not necessarily match the actual scale.

(Light emitting device)
First, a display device that is an example of the light-emitting device of the present invention will be described.

  FIG. 1 is a cross-sectional view showing a light emitting device (display device) according to an embodiment of the present invention. In the following description, for convenience of explanation, the upper side in FIG. 1 will be described as “upper” and the lower side as “lower”.

  A light-emitting device 100 shown in FIG. 1 includes a plurality of light-emitting elements 1R, 1G, and 1B corresponding to sub-pixels 100R (R pixels), 100G (G pixels), and 100B (B pixels), and has a bottom emission display. The panel is configured. In the present embodiment, an example in which an active matrix method is employed as a display device driving method will be described. However, a passive matrix method may be employed.

  The light emitting device 100 includes a circuit board 20, a plurality of light emitting elements 1 R, 1 G, and 1 B provided on the circuit board 20, and a sealing substrate 40.

  The circuit board 20 includes a substrate 21, an interlayer insulating film 22 provided on the substrate 21, a plurality of switching elements 23, and wirings 24.

  The substrate 21 is substantially transparent (colorless transparent, colored transparent or translucent). Thereby, the light from each light emitting element 1R, 1G, 1B can be extracted from the substrate 21 side. Examples of the constituent material of the substrate 21 include resin materials such as polyethylene terephthalate, polyethylene naphthalate, polypropylene, cycloolefin polymer, polyamide, polyethersulfone, polymethyl methacrylate, polycarbonate, and polyarylate, quartz glass, and soda glass. Such glass materials can be used, and one or more of these can be used in combination.

  In the case of a top emission structure in which light from the light emitting elements 1R, 1G, and 1B is extracted from the side opposite to the substrate 21, the substrate 21 may be an opaque substrate. And a substrate made of an oxide film (insulating film) on the surface of a metal substrate such as stainless steel, a substrate made of a resin material, and the like.

  On such a substrate 21, a plurality of switching elements 23 are arranged in a matrix. Each switching element 23 is provided corresponding to each light emitting element 1R, 1G, 1B, and is a driving transistor for driving each light emitting element 1R, 1G, 1B.

  Each switching element 23 includes a semiconductor layer 231 made of silicon, a gate insulating layer 232 formed on the semiconductor layer 231, a gate electrode 233 formed on the gate insulating layer 232, a source electrode 234, A drain electrode 235.

  An interlayer insulating film 22 made of an insulating material is formed so as to cover the plurality of switching elements 23. A wiring 24 is provided in the interlayer insulating film 22.

  On the interlayer insulating film 22, light emitting elements 1R, 1G, and 1B are provided corresponding to the switching elements 23, respectively. In the present embodiment, the light emitting element 1R is configured to emit red (R) light, the light emitting element 1G is configured to emit green (G) light, and the light emitting element 1B is blue (B). The light is emitted.

  Specifically, the light emitting element 1R (first light emitting element) includes an anode 3R (first electrode), a hole injection layer 4R, and a hole transport layer 5R (first hole transport layer) on the interlayer insulating film 22. , Light emitting functional layer 6R (first light emitting functional layer), hole transport layer 7 (common hole transport layer), light emitting functional layer 6B (second light emitting functional layer), electron transport layer 8, electron injection layer 9 and cathode 10 (Common cathode) is laminated in this order.

  Similarly, the light-emitting element 1G (third light-emitting element) includes an anode 3G (third electrode), a hole injection layer 4G, a hole transport layer 5G (third hole-transport layer), a light-emitting element on the interlayer insulating film 22. Functional layer 6G (third light emitting functional layer), hole transport layer 7 (common hole transport layer), light emitting functional layer 6B (second light emitting functional layer), electron transport layer 8, electron injection layer 9 and cathode 10 (common) The cathode) is laminated in this order.

  On the other hand, the light emitting element 1B (second light emitting element) has an anode 3B (second electrode), a hole injection layer 4B, a hole transport layer 5B (second hole transport layer), a hole on the interlayer insulating film 22. The transport layer 7 (common hole transport layer (intermediate layer)), the light emitting functional layer 6B (second light emitting functional layer), the electron transport layer 8, the electron injection layer 9, and the cathode 10 (common cathode) are laminated in this order. Yes.

  Here, the anodes 3R, 3G, and 3B constitute pixel electrodes individually provided for the corresponding light emitting elements 1R, 1G, and 1B, and are electrically connected to the drain electrode of the switching element 23 via the wiring 24. ing. Further, the hole injection layers 4R, 4G, and 4B, the hole transport layers 5R, 5G, and 5B, the light emitting functional layer 6R, and the light emitting functional layer 6G are also provided individually for the corresponding light emitting elements 1R, 1G, and 1B. . Hereinafter, the light emitting elements 1R, 1G, and 1B are collectively referred to as “light emitting element 1”, the anodes 3R, 3G, and 3B are collectively referred to as “anode 3”, and the hole injection layers 4R, 4G, and 4B are collectively referred to. The “hole injection layer 4” and the hole transport layers 5R, 5G, and 5B are collectively referred to as “hole transport layer 5”.

  On the other hand, the cathode 10 constitutes a common electrode provided in common to the light emitting elements 1R, 1G, and 1B. Further, the hole transport layer 7 (common hole transport layer), the light emitting functional layer 6B, the electron transport layer 8 and the electron injection layer 9 are also provided in common to the light emitting elements 1R, 1G and 1B.

  According to such a light emitting device 100, the hole transport layers 5R, 5G, and 5B, the light emitting functional layers 6R and 6G, and the like are individually formed for each element using a liquid phase process, and a gas phase process is used. The hole transport layer 7, the light emitting functional layer 6B, and the like can be formed in common for the three elements. Therefore, the light emitting elements 1R, 1G, and 1B can be efficiently manufactured.

  Further, when the light emitting elements 1R, 1G, and 1B are formed in this way, holes formed in the light emitting element 1B between the hole transport layer 5B and the light emitting functional layer 6B by the same vapor phase process as the light emitting functional layer 6B. The transport layer 7 can be provided, whereby the hole transport layer 5B and the light emitting functional layer 6B can be provided between the hole transport layer 5B and the light emitting functional layer 6B as compared with the case where the hole transport layer 5B and the light emitting functional layer 6B having different manufacturing methods are directly stacked. Electrical barriers related to carrier movement can be reduced. Therefore, carriers (holes) are smoothly transported to the light emitting functional layer 6B, and the light emission efficiency can be improved.

  A partition wall 31 (bank) made of a resin material is provided between the adjacent light emitting elements 1R, 1G, and 1B. Moreover, the sealing substrate 40 is joined to such light emitting elements 1R, 1G, and 1B through a resin layer 32 made of a thermosetting resin such as an epoxy resin.

  As described above, since each of the light emitting elements 1R, 1G, and 1B of the present embodiment is a bottom emission type, the sealing substrate 40 may be a transparent substrate or an opaque substrate. As a constituent material, the same material as the substrate 21 described above can be used.

Hereinafter, the light emitting elements 1R, 1G, and 1B will be described in detail.
In the light emitting elements 1R, 1G, 1B, electrons are supplied (injected) from the cathode 10 side to the light emitting functional layers 6R, 6G, 6B, and holes are supplied (injected) from the anodes 3R, 3G, 3B side. The In the light emitting functional layers 6R, 6G, and 6B, holes and electrons recombine, and excitons are generated by the energy released during the recombination, and the excitons return to the ground state. Emits energy (fluorescence or phosphorescence).

  Here, although the light emitting functional layers 6B are provided in the light emitting elements 1R and 1G, the light emitting functional layers 6R and 6G selectively emit light without causing the light emitting functional layer 6B to emit light. Thereby, the light emitting elements 1R, 1G, and 1B emit light in red, green, and blue, respectively.

Hereinafter, the configuration of each part of the light emitting elements 1R, 1G, and 1B will be briefly described.
(anode)
The anode 3 (3R, 3G, 3B) is an electrode that injects holes into the hole injection layer 4 (4R, 4G, 4B). As the constituent materials of the anodes 3R, 3G, and 3B, it is preferable to use materials having a large work function and excellent conductivity.

Specifically, the constituent materials of the anodes 3R, 3G, and 3B include, for example, ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), In ₃ O ₃ , SnO ₂ , Sb-containing SnO ₂ , and Al Examples thereof include oxides such as ZnO, Au, Pt, Ag, Cu, and alloys containing these, and one or more of these can be used in combination. The constituent materials of the anodes 3R, 3G, and 3B may be the same or different from each other, but by using the same materials, the anodes 3R, 3G, and 3B can be collectively formed. Productivity can be increased.

(Hole injection layer)
The hole injection layer 4 (4R, 4G, 4B) has a function of improving the hole injection efficiency from the anode 3 (3R, 3G, 3B).

  A constituent material (hole injection material) of each of the hole injection layers 4R, 4G, and 4B is not particularly limited. PSS) and a high-molecular hole injection material such as polystyrene, polypyrrole, polyaniline, oligoaniline, polyacetylene, and derivatives thereof are included, and one of these is used alone or 2 A combination of more than one species can be used. The constituent materials of the hole injection layers 4R, 4G, and 4B may be the same as or different from each other. However, the constituent materials of the hole injection layers 4R, 4G, and 4B are the same as each other. The hole injection layers 4R, 4G, and 4B having stable characteristics can be formed at low cost and high productivity.

  The thicknesses of the hole injection layers 4R, 4G, and 4B are not particularly limited, but are preferably in the range of 10 nm to 150 nm, and more preferably in the range of 20 nm to 100 nm. .

(Hole transport layer)
The hole transport layer 5R (first hole transport layer) has a function of transporting holes injected from the anode 3R through the hole injection layer 4R to the light emitting functional layer 6R. Similarly, the hole transport layer 5G (third hole transport layer) has a function of transporting holes injected from the anode 3G through the hole injection layer 4G to the light emitting functional layer 6G.

  In addition, the hole transport layer 5R has an electron blocking property and also has a function of preventing a functional deterioration of the hole injection layer 4R due to electrons entering the hole injection layer 4R. Similarly, the hole transport layer 5G has an electron blocking property, and also has a function of preventing a functional deterioration of the hole injection layer 4G due to electrons entering the hole injection layer 4G.

  The hole transport layer 5B (second hole transport layer) and the hole transport layer 7 (hole transport layer 7) pass holes injected from the anode 3B through the hole injection layer 4B to the light emitting functional layer 6B. Has the function of transporting.

  In addition, the hole transport layers 5B and 7 have an electron blocking property, and also have a function of preventing functional degradation of the hole injection layer 4B due to electrons entering the hole injection layer 4B. Since the hole transport layer 7 is extremely thin as will be described later, the electron block property of the hole transport layer 7 alone is extremely low, and does not inhibit the movement of electrons in the light emitting elements 1R and 1G.

  Examples of the constituent material of the hole transport layers 5R, 5G, and 5B include triphenylamine polymers such as TFB (poly (9,9-dioctyl-fluorene-co-N- (4-butylphenyl) -diphenylamine)). Amine-based compounds, polyfluorene derivatives (PF), polyparaphenylene vinylene derivatives (PPV), polyparaphenylene derivatives (PPP), polyvinylcarbazole (PVK), polythiophene derivatives, polysilanes including polymethylphenylsilane (PMPS) High molecular hole transport materials such as m-MTDATA (4,4 ', 4 "-tris (N-3-methylphenylamino) -triphenylamine), TCTA (4,4', 4"- Low molecular hole transport materials such as tri (N-carbazole group) triphenylamine) and α-NPD (bis (N- (1-naphthyl) -N-phenyl) benzidine). 1 type or 2 types or more of these can be used in combination. The constituent materials of the hole transport layers 5R, 5G, and 5B (first hole transport layer, second hole transport layer, and third hole transport layer) may be the same as or different from each other. , The constituent materials of the hole transport layers 5R, 5G (first hole transport layer, third hole transport layer) are the same, and the constituent materials of the hole transport layer 5B (second hole transport layer) are By being different from the hole transport layers 5R and 5G, the light emission balance between the light emitting elements 1R and 1G and the light emitting element 1B can be easily adjusted.

  Moreover, it is preferable that the hole transport layers 5R and 5G are each configured using a high-molecular hole transport material, and the hole transport layers 5B and 7 are each configured using a low-molecular hole transport material. . Thereby, the hole transport layers 5R and 5G having high dimensional accuracy can be efficiently formed using a liquid phase process. Further, by forming both the light emitting functional layers 6R and 6G and the hole transporting layers 5R and 5G using a liquid phase process, carriers (holes) are transferred from the hole transporting layers 5R and 5G to the light emitting functional layers 6R and 6G. It can be transported smoothly.

  In addition, the hole transport layers 5B and 7 having high dimensional accuracy can be efficiently formed using a vapor phase process. In particular, by forming the hole transport layer 7 using a vapor phase process, the extremely thin hole transport layer 7 can be formed with high accuracy (with good controllability). Further, even if the hole transport layer 5B and the hole transport layer 7 are formed by different manufacturing methods, since the hole transporting materials constituting them are both low molecules, the hole transport layer 5B is transported from the hole transport layer 5B. Carriers (holes) can be smoothly transported to the layer 7.

  Here, when the hole transport layer 5B is formed using a low molecular hole transport material, the hole transport layer 5B includes a high molecular hole transport material in addition to the low molecular hole transport material. The content of the low-molecular hole transport material in the hole transport layer 5B is preferably 50 wt% or more and 100 wt% or less, and more preferably 70 wt% or more and 100 wt% or less. Preferably, it is 90 wt% or more and 100 wt% or less.

  Moreover, as a constituent material of the hole transport layer 7, for example, m-MTDATA (4,4 ′, 4 ″ -tris (N-3-methylphenylamino) -triphenylamine), TCTA (4,4 ′, 4 ″ -tri (N-carbazole group) triphenylamine), α-NPD (bis (N- (1-naphthyl) -N-phenyl) benzidine) One or two or more of them can be used in combination. The constituent material of the hole transport layer 7 (common hole transport layer) may be the same as or different from the hole transport layers 5R, 5G, and 5B. By containing the same or similar material as the constituent material of the (hole transport layer), carriers (holes) can be smoothly transported from the hole transport layer 5B to the light emitting functional layer 6B through the hole transport layer 7. Can do.

  The thicknesses of the hole transport layers 5R, 5G, and 5B are not particularly limited, but are preferably in the range of 15 nm to 25 nm.

  The thickness t of the hole transport layer 7 is 2 nm or less, preferably 0.1 nm or more and 1.5 nm or less, more preferably 0.1 nm or more and 1 nm or less, and still more preferably 0 nm or less. .1 nm or more and 0.9 nm or less. Thereby, in the light emitting elements 1R and 1G, the thickness of the hole transport layer 7 provided between the light emitting functional layers 6R and 6G and the light emitting functional layer 6B is extremely thin. Carriers (electrons) can be delivered to 6R and 6G. Therefore, the light emitting functional layers 6R and 6G can selectively emit light without causing the light emitting functional layers 6B to emit light in the light emitting elements 1R and 1G. Since the thickness of the hole transport layer 7 is extremely thin, an increase in driving voltage of the light emitting elements 1R, 1G, and 1B due to the provision of the hole transport layer 7 can be suppressed.

  Here, since the constituent material of the hole transport layer 7 has an electron blocking property as described above, the light emitting functional layer 6B can efficiently emit light by utilizing the electron blocking property of the hole transport layer 7 in the light emitting element 1B. be able to. On the other hand, in the light emitting elements 1R and 1G, if the electron blocking property of the hole transport layer 7 is too high, light emission by the light emitting functional layers 6R and 6G does not occur or the light emission efficiency is remarkably reduced. Therefore, it is extremely useful to reduce the thickness of the hole transport layer 7 to make the electron block property of the hole transport layer 7 in the light emitting elements 1R and 1G low.

  On the other hand, when the thickness t of the hole transport layer 7 is too thin, the above-described effect by providing the hole transport layer 7 tends to become extremely small. On the other hand, when the thickness t of the hole transport layer 7 is too thick, the driving voltage of the light emitting elements 1R and 1G increases rapidly (the light emission efficiency decreases rapidly), or the light emitting functional layer in the light emitting elements 1R and 1G. 6B emits light, and light emission of a desired color cannot be obtained.

(Light emitting functional layer)
The light emitting functional layer 6R is provided in contact with the hole transport layer 5R. The light emitting functional layer 6G is provided in contact with the hole transport layer 5G. The light emitting functional layer 6 </ b> B is provided in contact with the hole transport layer 7.

  Each of the light emitting functional layers 6R, 6G, and 6B includes a light emitting material. The light emitting material is not particularly limited, and various fluorescent materials and phosphorescent materials can be used singly or in combination, and the light emitting functional layer 6R is made of a red fluorescent material or a red phosphorescent material as the light emitting material. The light emitting functional layer 6G uses a green fluorescent material or a green phosphorescent material as a light emitting material, and the light emitting functional layer 6B uses a blue fluorescent material or a blue phosphorescent material as a light emitting material.

  The red fluorescent material is not particularly limited as long as it emits red fluorescence. For example, perylene derivatives such as diindenoperylene derivatives, europium complexes, benzopyran derivatives, rhodamine derivatives, benzothioxanthene derivatives, porphyrin derivatives, Nile Red, 2- (1,1-dimethylethyl) -6- (2- (2,3,6,7-tetrahydro-1,1,7,7-tetramethyl-1H, 5H-benzo (ij) quinolidine- 9-yl) ethenyl) -4H-pyran-4H-ylidene) propanedinitrile (DCJTB), 4- (dicyanomethylene) -2-methyl-6- (p-dimethylaminostyryl) -4H-pyran (DCM), ADS111RE (manufactured by American Dice Source) and the like can be mentioned.

  The red phosphorescent material is not particularly limited as long as it emits red phosphorescence. For example, Bt2Ir (acac) (Bis (2-phenylbenxothiozolato-N, C2 ′) Iridium (III) (acetylacetonate)), Btp2Ir (acac ) (Bis (2,2′-benzothienyl) -pyridinato-N, C3) Iridium (acetylacetonate)), PtOEP (2,3,7,8,12,13,17,18-Octaethyl-21H, And platinum complexes such as 23H-porphine and platinum (II)).

  The green fluorescent material is not particularly limited as long as it emits green fluorescence. For example, quinacridone such as coumarin derivatives and quinacridone derivatives and derivatives thereof, 9,10-bis [(9-ethyl-3-carbazole)- Vinylenyl] -anthracene, poly (9,9-dihexyl-2,7-vinylenefluorenylene), poly [(9,9-dioctylfluorene-2,7-diyl) -co- (1,4-diphenylene-vinylene) -2-methoxy-5- {2-ethylhexyloxy} benzene)], poly [(9,9-dioctyl-2,7-divinylenefluorenylene) -ortho-co- (2-methoxy-5- (2 -Ethoxylhexyloxy) -1,4-phenylene)], ADS109GE (manufactured by American Dice Source), and the like.

  The green phosphorescent material is not particularly limited as long as it emits green phosphorescence. For example, Ir (ppy) 3 (Fac-tris (2-phenypyridine) iridium), Ppy2Ir (acac) (Bis (2-phenyl-) pyridinato-N, C2) Iridium (acetylacetone)) and the like.

  The blue fluorescent material is not particularly limited as long as it emits blue fluorescence. For example, distyrylamine derivatives such as distyryldiamine compounds, fluoranthene derivatives, pyrene derivatives, perylene and perylene derivatives, anthracene derivatives, benzo Oxazole derivatives, benzothiazole derivatives, benzimidazole derivatives, chrysene derivatives, phenanthrene derivatives, distyrylbenzene derivatives, tetraphenylbutadiene, 4,4′-bis (9-ethyl-3-carbazovinylene) -1,1′-biphenyl (BCzVBi) ), Poly [(9.9-dioctylfluorene-2,7-diyl) -co- (2,5-dimethoxybenzene-1,4-diyl)], poly [(9,9-dihexyloxyfluorene-2, 7-diyl) -ortho-co- (2-me Xyl-5- {2-ethoxyhexyloxy} phenylene-1,4-diyl)], poly [(9,9-dioctylfluorene-2,7-diyl) -co- (ethylnylbenzene)], ADS136BE (American) Die Source).

  The blue phosphorescent material is not particularly limited as long as it emits blue phosphorescence. For example, FIrpic (Iridium-bis (4,6-difluorophenyl-pyridinato-N, C2) -picolinate), Ir (pmb) 3 (Iridium-tris (1-phenyl-3-methylbenzimidazolin-2-ylidene-C, C (2) ′), FIrN4 (Iridium (III) bis (4,6-difluorophenylpyridinato) (5- (pyridin-2-yl) -Tetrazolate)), FIrtaz (Iridium (III) bis (4,6-difluorophenylpyridinato) (5- (pyridine-2-yl) -1,2,4-triazolate)) and the like.

  In addition, the light emitting functional layers 6R, 6G, and 6B may contain a host material to which the light emitting material is added as a guest material in addition to the light emitting material described above. This host material recombines holes and electrons to generate excitons and to transfer the exciton energy to the luminescent material (Felster movement or Dexter movement) to excite the luminescent material. Have. In the case of using such a host material, for example, the host material can be used by doping a light emitting material that is a guest material as a dopant.

  Such a host material is not particularly limited as long as it exhibits the functions described above for the light emitting material to be used. For example, TDAPB (1,3,5-tris- (N, N-bis -(4-methoxy-phenyl) -aminophenyl) -benzene), CBP (4,4'-bis (9-dicarbazolyl) -2,2'-biphenyl), BAlq (Bis- (2-methyl-8-quinolinolate) ) -4- (phenylphenolate) aluminium), mCP (N, N-dicarbazolyl-3,5-benzene: CBP derivative), CDBP (4,4′-bis (9-carbazolyl) -2,2′-dimethyl-biphenyl) ), DCB (N, N′-Dicarbazolyl-1,4-dimethene-benzene), P06 (2,7-bis (diphenylphosphineoxide) 9,9-dimethylfluorene), SimCP (3,5-bis (9-carbazolyl) tetraphenylsilane) ), UGH3 (W-bis (triphenylsilyl benzene) host material of low molecular weight can be mentioned, such as may be used singly or in combination of two or more of them.

  The constituent materials of the light emitting functional layers 6R and 6G are preferably soluble in a solvent capable of dissolving the constituent materials of the hole transport layers 5R and 5G described above. Thereby, the light emitting functional layers 6R and 6G and the hole transport layers 5R and 5G can be formed by a liquid phase process using the same solvent. That is, when the light emitting functional layers 6R and 6G are formed by a liquid phase process, the same solvent as that used when the hole transport layers 5R and 5G are formed by a liquid phase process can be used. As a result, the adhesion or affinity of the interface between the light emitting functional layers 6R, 6G and the hole transport layers 5R, 5G is increased, and carriers (positive) from the hole transport layers 5R, 5G to the light emitting functional layers 6R, 6G are increased. Hole) can be improved.

  The constituent materials of the light emitting functional layers 6R and 6G are preferably composed of a low molecular material as a main material, and more preferably composed of a low molecular guest material and a low molecular host material as a main material. preferable. Thereby, the luminous efficiency of the light emitting functional layers 6R and 6G can be increased, and the decrease in the luminous efficiency of the light emitting elements 1R and 1G due to the provision of the hole transport layer 7 can be compensated. As a result, the light emission balance between the light emitting elements 1R and 1G and the light emitting element 1B can be made excellent. From such a viewpoint, the content of the low molecular material in the light emitting functional layers 6R and 6G is preferably 60 wt% or more, more preferably 80 wt% or more, and further preferably 90 wt% or more. .

  The thicknesses of such light emitting functional layers 6R, 6G, and 6B are not particularly limited, but are preferably in the range of 5 nm to 100 nm, and more preferably in the range of 10 nm to 50 nm.

(Electron transport layer)
The electron transport layer 8 has a function of transporting electrons injected from the cathode 10 through the electron injection layer 9 to the light emitting functional layer 6B.

  As a constituent material (electron transport material) of the electron transport layer 8, for example, BALq, OXD-1 (1,3,5-tri (5- (4-tert-butylphenyl) -1,3,4-oxadi) Azole)), BCP (Bathocuproine), PBD (2- (4-biphenyl) -5- (4-tert-butylphenyl) -1,2,4-oxadiazole), TAZ (3- (4-biphenyl) -5- (4-tert-butylphenyl) -1,2,4-triazole), DPVBi (4,4'-bis (1,1-bis-diphenylethenyl) biphenyl), BND (2,5-bis ( 1-naphthyl) -1,3,4-oxadiazole), DTVBi (4,4′-bis (1,1-bis (4-methylphenyl) ethenyl) biphenyl), BBD (2,5-bis (4 -Biphenylyl) -1, 3,4-oxadiazole), tris (8-quinolinolato) aluminum (Alq3), oxadiazole derivatives, oxazole derivatives, phenanthoroline derivatives, anthraquinodimethane derivatives, benzoquinone derivatives, naphthoquinone derivatives, anthraquinone derivatives, tetracyano Anthraquinodimethane derivatives, fluorene derivatives, diphenyldicyanoethylene derivatives, diphenoquinone derivatives, hydroxyquinoline derivatives and the like can be mentioned, and one or more of these can be used in combination.

  Although the thickness of the electron carrying layer 8 is not specifically limited, It is preferable to exist in the range of 1 nm or more and 100 nm or less, and it is more preferable to exist in the range of 5 nm or more and 50 nm or less.

  The electron transport layer 8 can be omitted depending on the constituent material and thickness of other layers.

(Electron injection layer)
The electron injection layer 9 has a function of improving the efficiency of electron injection from the cathode 10.

  Examples of the constituent material (electron injection material) of the electron injection layer 9 include various inorganic insulating materials and various inorganic semiconductor materials.

  Examples of such inorganic insulating materials include alkali metal chalcogenides (oxides, sulfides, selenides, tellurides), alkaline earth metal chalcogenides, alkali metal halides, and alkaline earth metal halides. Of these, one or two or more of these can be used in combination. By forming the electron injection layer using these as main materials, the electron injection property can be further improved. In particular, alkali metal compounds (alkali metal chalcogenides, alkali metal halides, and the like) have a very low work function, and the light-emitting element 1 can obtain high luminance by forming the electron injection layer 9 using the work function. Become.

Examples of the alkali metal chalcogenide include Li ₂ O, LiO, Na ₂ S, Na ₂ Se, and NaO. Examples of the alkaline earth metal chalcogenide include CaO, BaO, SrO, BeO, BaS, MgO, and CaSe. Examples of the alkali metal halide include CsF, LiF, NaF, KF, LiCl, KCl, and NaCl. Examples of the alkaline earth metal halide include CaF ₂ , BaF ₂ , SrF ₂ , MgF ₂ , and BeF ₂ .

  In addition, as the inorganic semiconductor material, for example, an oxide including at least one element of Li, Na, Ba, Ca, Sr, Yb, Al, Ga, In, Cd, Mg, Si, Ta, Sb, and Zn , Nitrides, oxynitrides, and the like, and one or more of these can be used in combination.

  The thickness of the electron injection layer 9 is not particularly limited, but is preferably in the range of 0.01 nm to 10 nm, and more preferably in the range of 0.1 nm to 10 nm.

  The electron injection layer 9 can be omitted depending on the constituent material and thickness of other layers.

(cathode)
The cathode 10 is an electrode that injects electrons into the electron transport layer 8 through the electron injection layer 9. As a constituent material of the cathode 10, it is preferable to use a material having a small work function.

  Examples of the constituent material of the cathode 10 include Li, Mg, Ca, Sr, La, Ce, Er, Eu, Sc, Y, Yb, Ag, Cu, Al, Cs, Rb, and alloys containing these. These can be used alone or in combination of two or more thereof (for example, a multi-layer laminate).

  In particular, when an alloy is used as the constituent material of the cathode 10, it is preferable to use an alloy containing a stable metal element such as Ag, Al, or Cu, specifically, an alloy such as MgAg, AlLi, or CuLi. By using such an alloy as a constituent material of the cathode 10, the electron injection efficiency and stability of the cathode 10 can be improved.

  Moreover, since the light emitting element 1 of this embodiment is a bottom emission type, the cathode 10 does not need to have a light transmittance. In the case of the bottom emission type, as the constituent material of the cathode 10, for example, a metal or an alloy such as Al, Ag, AlAg, and AlNd is preferably used. By using such a metal or alloy as a constituent material of the cathode 10, the electron injection efficiency and stability of the cathode 10 can be improved.

  The thickness of the cathode 10 in the case of the bottom emission type is not particularly limited, but is preferably in the range of 50 nm to 1000 nm, and more preferably in the range of 100 nm to 500 nm.

  In addition, when the light emitting element 1 is a top emission type, it is preferable to use a metal or an alloy such as MgAg, MgAl, MgAu, and AlAg as a constituent material of the cathode 10. By using such a metal or alloy as the constituent material of the cathode 10, it is possible to improve the electron injection efficiency and stability of the cathode 10 while ensuring the light transmittance of the cathode 10.

  The thickness of the cathode 10 in the case of the top emission type is not particularly limited, but is preferably in the range of 1 nm to 50 nm, and more preferably in the range of 5 nm to 20 nm.

  According to the light emitting device 100 configured as described above, the hole transport layers 5R, 5G, and 5B and the light emitting functional layers 6R and 6G are individually provided for each element using a liquid phase process, as will be described in detail later. In addition, the hole transport layer 7 and the light emitting functional layer 6B can be formed in common to the light emitting elements 1R, 1G, and 1B, respectively, by using a vapor phase process. Therefore, the light emitting elements 1R, 1G, and 1B can be efficiently manufactured.

  When the light emitting elements 1R, 1G, and 1B are formed in this way, in the light emitting element 1B, the hole transport layer formed by the same vapor phase process as the light emitting functional layer 6B between the hole transporting layer 5B and the light emitting functional layer 6B. 7 so that the number of carriers between the hole transport layer 5B and the light emitting functional layer 6B can be reduced as compared with the case where the hole transport layer 7 and the light emitting functional layer 6B having different manufacturing methods are directly stacked. It is possible to reduce electrical barriers related to movement. Therefore, carriers (holes) are smoothly transported to the light emitting functional layer 6B, and the light emission efficiency can be improved.

  On the other hand, in the light emitting elements 1R and 1G, since the thickness of the hole transport layer 7 provided between the light emitting functional layers 6R and 6G and the light emitting functional layer 6B is extremely thin, the light emitting functional layer 6B to the light emitting functional layer 6R. , 6G carrier (electrons) can be delivered. Therefore, the light emitting functional layers 6R and 6G can selectively emit light without causing the light emitting functional layers 6B to emit light in the light emitting elements 1R and 1G.

  In addition, since the thickness of the hole transport layer 7 is extremely thin, an increase in the driving voltage of the light emitting elements 1R, 1G, and 1B due to the provision of the hole transport layer 7 can be suppressed.

  As described above, in the light emitting device 100 including the plurality of light emitting elements 1R, 1G, and 1B having different emission colors, the light emitting devices 1R, 1G, and 1B are improved in light emission efficiency, and the light emitting device 100 is efficiently operated. Can be manufactured.

(Method for manufacturing light emitting device)
Hereinafter, an example of a method for manufacturing the above-described light emitting device 100 will be described.

  2-4 is a figure for demonstrating the manufacturing method of the light-emitting device shown in FIG. Hereinafter, each process is demonstrated one by one.

[1]
First, the circuit board 20 is prepared. As shown in FIG. 2A, after the anodes 3R, 3G, and 3B are formed on the circuit board 20, the partition walls 31 are formed.

  The anodes 3R, 3G, and 3B are formed by, for example, forming an electrode material on the circuit board 20 by using a vapor deposition method such as an evaporation method or a CVD method, and then patterning the electrode material by etching or the like. can get.

  The partition wall 31 can be formed by patterning using a photolithography method or the like so that the anodes 3R, 3G, and 3B are exposed.

Here, the constituent material of the partition wall 31 is selected in consideration of heat resistance, liquid repellency, ink solvent resistance, adhesion to the circuit board 20 and the like. Specifically, examples of the constituent material of the partition wall 31 include an organic material such as an acrylic resin, a polyimide resin, and an epoxy resin, and an inorganic material such as SiO ₂ .

  In addition, after the formation of the anodes 3R, 3G, and 3B and the partition walls 31, the surfaces of the anodes 3R, 3G, and 3B and the partition walls 31 may be subjected to oxygen plasma treatment as necessary. Thereby, lyophilicity is imparted to the surfaces of the anodes 3R, 3G, 3B, organic substances adhering to the surfaces of the anodes 3R, 3G, 3B and the partition wall 31 are removed (washed), and the anodes 3R, 3G, 3B The work function near the surface can be adjusted.

  Here, as conditions for the oxygen plasma treatment, for example, the plasma power is about 100 to 800 W, the oxygen gas flow rate is about 50 to 100 mL / min, and the conveyance speed of the member to be treated (anode 3R, 3G, 3B) is 0.5 to 10 mm / min. It is preferable that the temperature of the circuit board 20 is about 70 to 90 ° C. for about sec.

Further, after this oxygen plasma treatment, it is preferable to perform a plasma treatment using a fluorine-based gas such as CF ₄ as a treatment gas. As a result, the fluorine-based gas reacts only on the surface of the partition wall 31 made of a photosensitive resin, which is an organic material, to make the liquid repellent. Thereby, it is possible to reduce the unintentional wetting and spreading of the liquid applied in the partition wall 31.

[2]
Next, as shown in FIG. 2B, the ink 4 a for forming the hole injection layer is applied from the inkjet head 200 onto the anodes 3 </ b> R, 3 </ b> G, and 3 </ b> B in the partition wall 31.

  The ink 4a is obtained by dissolving the constituent material of the hole injection layers 4R, 4G, and 4B or a precursor thereof in a solvent or dispersing in a dispersion medium. Examples of the solvent or dispersion medium include various inorganic solvents, various organic solvents, or mixed solvents containing these.

  Thereafter, the ink 4a on the anode 3 is dried (desolvent or dedispersing medium) and heat-treated as necessary, so that the hole injection layers 4R, 4G, and 4B are formed as shown in FIG. Form.

  Drying can be performed, for example, by standing in an atmospheric pressure or reduced pressure atmosphere, heat treatment, spraying of an inert gas, etc., but after drying under reduced pressure for about 10 minutes to 1 hour in a vacuum state of 5 Pa or less. It is preferable to heat and dry at 150 ° C. to 250 ° C. for about 5 minutes to 30 minutes in an atmospheric pressure oven. Thereby, it is possible to form the hole injection layers 4R, 4G, and 4B that are flat and have excellent characteristics.

As described above, the hole injection layers 4R, 4G, and 4B are formed by the liquid phase process using the ink 4a.
Is formed.

[3]
Next, as shown in FIG. 2 (d), the ink 5 a for forming a hole transport layer is applied from the inkjet head 200 onto the hole injection layers 4 R and 4 G in the partition wall 31.

  The ink 5a is obtained by dissolving the constituent material of the hole transport layers 5R and 5G or a precursor thereof in a solvent or dispersing in a dispersion medium. Examples of the solvent or dispersion medium include various inorganic solvents, various organic solvents, or mixed solvents containing these.

  Thereafter, the ink 5a on the hole injection layers 4R and 4G is dried (desolvent or dedispersion medium), and heat-treated as necessary, so that as shown in FIG. 5G is formed.

  Drying can be performed, for example, by standing in an atmospheric pressure or reduced pressure atmosphere, heat treatment, spraying of an inert gas, etc., but after drying under reduced pressure for about 10 minutes to 1 hour in a vacuum state of 5 Pa or less. It is preferable to heat dry at 150 ° C. to 250 ° C. for about 5 to 30 minutes in an oven in a nitrogen atmosphere. Thereby, the flat and excellent hole transport layers 5R and 5G having excellent characteristics can be formed.

  As described above, the hole transport layers 5R and 5G are formed by the liquid phase process using the ink 5a.

[4]
Next, as shown in FIG. 3B, ink 6a and 6b for forming a light emitting functional layer are applied from the inkjet head 200 onto the hole transport layers 5R and 5G in the partition wall 31, respectively.

  The ink 6a is obtained by dissolving the constituent material of the light emitting functional layer 6R or its precursor in a solvent or dispersing it in a dispersion medium. The ink 6b is obtained by dissolving the constituent material of the light emitting functional layer 6G or its precursor in a solvent or dispersing it in a dispersion medium. Examples of the solvent or dispersion medium include various inorganic solvents, various organic solvents, or mixed solvents containing these.

  Thereafter, the inks 6a and 6b on the hole transport layers 5R and 5G are dried (desolvent or dedispersion medium), and heat-treated as necessary, so that a light emitting functional layer is obtained as shown in FIG. 6R and 6G are formed.

  Drying can be performed, for example, by standing in an atmospheric pressure or reduced pressure atmosphere, heat treatment, spraying of an inert gas, etc., but after drying under reduced pressure for about 10 minutes to 1 hour in a vacuum state of 5 Pa or less. It is preferable to heat dry at 150 ° C. to 250 ° C. for about 5 to 30 minutes in an oven in a nitrogen atmosphere. Thereby, the light emitting functional layers 6R and 6G having flat and excellent characteristics can be formed.

  As described above, the light emitting functional layers 6R and 6G are formed by the liquid phase process using the inks 6a and 6b.

[5]
Next, as shown in FIG. 3 (d), the ink 5 b for forming a hole transport layer is applied from the inkjet head 200 onto the hole injection layer 4 B in the partition wall 31.

  The ink 5b is obtained by dissolving the constituent material of the hole transport layer 5B or its precursor in a solvent or dispersing it in a dispersion medium. Examples of the solvent or dispersion medium include various inorganic solvents, various organic solvents, or mixed solvents containing these.

  Thereafter, the ink 5b on the hole injection layer 4B is dried (desolvent or dedispersion medium), and heat-treated as necessary to form the hole transport layer 5B as shown in FIG. 4A. To do.

  Drying can be performed, for example, by standing in an atmospheric pressure or reduced pressure atmosphere, heat treatment, spraying of an inert gas, etc., but after drying under reduced pressure for about 10 minutes to 1 hour in a vacuum state of 5 Pa or less. It is preferable to heat dry at 150 ° C. to 250 ° C. for about 5 to 30 minutes in an oven in a nitrogen atmosphere. Thereby, the hole transport layer 5B having flat and excellent characteristics can be formed.

  As described above, the hole transport layer 5B is formed by the liquid phase process using the ink 5b.

[6]
Next, on the light emitting functional layers 6R and 6G and the hole injection layer 5B, the hole transport layer 7, the light emitting functional layer 6B, the electron transport layer 8, and the electron injection layer 9 are covered so as to straddle the partition wall 31. And the cathode 10 are formed in this order.

  The hole transport layer 7, the light emitting functional layer 6 </ b> B, the electron transport layer 8, the electron injection layer 9, and the cathode 10 can be formed by, for example, a vapor phase process using a dry plating method such as vacuum deposition.

[7]
Finally, as shown in FIG. 4C, the cathode 10 is bonded to the sealing substrate 40 via the resin layer 32 (sealing layer). Thereby, the light emitting device 100 is obtained.

  As described above, the hole transport layers 5R, 5G, and 5B and the light emitting functional layers 6R and 6G are individually formed for each element using a liquid phase process, and the hole transport layer 7 is formed using a gas phase process. The light emitting functional layers 6B are formed in common to the light emitting elements 1R, 1G, and 1B, respectively, and the light emitting elements 1R, 1G, and 1B can be efficiently manufactured.

(Electronics)
FIG. 5 is a perspective view showing a configuration of a mobile (or notebook) personal computer to which the electronic apparatus of the present invention is applied.

  In this figure, a personal computer 1100 includes a main body 1104 provided with a keyboard 1102 and a display unit 1106 provided with a display. The display unit 1106 is rotatable with respect to the main body 1104 via a hinge structure. It is supported by.

  In the personal computer 1100, the display unit included in the display unit 1106 is configured by the light emitting device 100 described above.

  FIG. 6 is a perspective view showing a configuration of a mobile phone (including PHS) to which the electronic apparatus of the present invention is applied.

In this figure, a cellular phone 1200 includes a plurality of operation buttons 1202, an earpiece 1204 and a mouthpiece 1206, and a display unit.
In the cellular phone 1200, the display unit is configured by the light emitting device 100 described above.

  FIG. 7 is a perspective view showing the configuration of a digital still camera to which the electronic apparatus of the present invention is applied. In this figure, connection with an external device is also simply shown.

  Here, an ordinary camera sensitizes a silver halide photographic film with a light image of a subject, whereas a digital still camera 1300 photoelectrically converts a light image of a subject with an imaging device such as a CCD (Charge Coupled Device). An imaging signal (image signal) is generated.

  A display unit is provided on the back of a case (body) 1302 in the digital still camera 1300, and is configured to display based on an imaging signal from the CCD, and functions as a finder that displays an object as an electronic image.

  In the digital still camera 1300, the display unit is configured by the light emitting device 100 described above.

  A circuit board 1308 is installed inside the case. The circuit board 1308 is provided with a memory that can store (store) an imaging signal.

  A light receiving unit 1304 including an optical lens (imaging optical system), a CCD, and the like is provided on the front side of the case 1302 (on the back side in the illustrated configuration).

  When the photographer confirms the subject image displayed on the display unit and presses the shutter button 1306, the CCD image pickup signal at that time is transferred and stored in the memory of the circuit board 1308.

  In the digital still camera 1300, a video signal output terminal 1312 and an input / output terminal 1314 for data communication are provided on the side surface of the case 1302. As shown in the figure, a television monitor 1430 is connected to the video signal output terminal 1312 and a personal computer 1440 is connected to the data communication input / output terminal 1314 as necessary. Further, the imaging signal stored in the memory of the circuit board 1308 is output to the television monitor 1430 or the personal computer 1440 by a predetermined operation.

Such an electronic apparatus of the present invention has excellent reliability.
In addition to the personal computer (mobile personal computer) of FIG. 5, the mobile phone of FIG. 6, and the digital still camera of FIG. 7, the electronic apparatus of the present invention includes, for example, a television, a video camera, a viewfinder type, Monitor direct-view video tape recorder, laptop personal computer, car navigation system, pager, electronic notebook (including communication function), electronic dictionary, calculator, electronic game device, word processor, workstation, video phone, security TV Monitors, electronic binoculars, POS terminals, devices equipped with touch panels (for example, cash dispensers and automatic ticket vending machines for financial institutions), medical devices (for example, electronic thermometers, blood pressure monitors, blood glucose meters, electrocardiographs, ultrasound diagnostic devices, internal Endoscope display device), fish finder, various measuring instruments, Vessels such (e.g., gages for vehicles, aircraft, and ships), a flight simulator, various monitors, and a projection display such as a projector.

  The light emitting device and the electronic apparatus of the present invention have been described based on the illustrated embodiments, but the present invention is not limited to these.

Next, specific examples of the present invention will be described.
1. Manufacturing of light-emitting elements

(Example 1)
<1> First, a transparent glass substrate having a thickness of 0.5 mm was prepared. Next, an ITO electrode (first anode, second anode, and third anode) having a thickness of 100 nm was formed as a pixel electrode of each of the RGB pixels on the substrate by sputtering. Thereafter, an insulating layer made of an acrylic resin was formed, and then this insulating layer was patterned using a photolithography method so as to expose each ITO electrode, thereby forming a partition (bank).

  And after immersing a board | substrate in order of acetone and 2-propanol and ultrasonically cleaning, oxygen plasma treatment and argon plasma treatment were performed. Each of these plasma treatments was performed at a plasma power of 100 W, a gas flow rate of 20 sccm, and a treatment time of 5 seconds with the substrate heated to 70 to 90 ° C.

  <2> Next, the hole injection layer forming ink is filled in the respective partition walls of the RGB pixels by the ink jet method and applied onto the ITO electrode, and then dried under reduced pressure and then heat-treated (baked). A hole injection layer having a thickness of 50 nm was formed.

  Here, a 0.5 wt% aqueous dispersion of PEDOT: PSS was used as the hole injection layer forming ink. The firing was performed under atmospheric pressure, the firing temperature was 200 ° C., and the firing time was 10 minutes.

  <3> Next, the hole transport layer forming ink is filled in each partition wall of the RG pixel by an ink jet method and applied onto the hole injection layer, and then dried under reduced pressure, and then heat-treated (baked). As a result, a hole transport layer (first and third hole transport layers) having a thickness of 20 nm was formed.

  Here, a tetramethylbenzene solution containing 1.5 wt% of TFB (poly (9,9-dioctyl-fluorene-co-N- (4-butylphenyl) -diphenylamine)) is used as an ink for forming a hole transport layer. It was. The firing was performed in a glove box filled with nitrogen, the firing temperature was 200 ° C., and the firing time was 30 minutes.

  <4> Next, the light emitting functional layer forming ink is filled in each partition wall of the RG pixel by the ink jet method and applied onto the hole transport layer, and then dried under reduced pressure, and then heat-treated (baked). As a result, a light emitting functional layer (first and third light emitting functional layers) having a thickness of 20 nm was formed.

  Here, as the light emitting functional layer forming ink, CBP (4,4′-bis (9-dicarbazoyl) -2,2′-biphenyl), Ir (ppy) 3 (Fac-tris (2-phenylpyridine) iridium) A tetramethylbenzene solution (concentration: 1.2 wt%) mixed at a weight ratio of 90:10 was used. Moreover, drying was performed by drying under reduced pressure for 10 minutes at a vacuum degree of 5 Pa or less. The firing was performed in a glove box filled with nitrogen, the firing temperature was 220 ° C., and the firing time was 10 minutes.

  <5> Next, the ink for forming the hole transport layer is filled in the partition walls of the B pixel by the ink jet method and applied onto the hole injection layer, followed by drying under reduced pressure and then heat treatment (firing). Thus, a 20 nm-thick hole transport layer (second hole transport layer) was formed.

  Here, as the hole transport layer forming ink, a CHB (cyclohexylbenzene) solution containing α-NPD which is a low molecular hole transport material at a concentration of 0.3 wt% was used. The firing was performed in a glove box filled with nitrogen, the firing temperature was 160 ° C., and the firing time was 10 minutes.

  <6> Next, a hole transport layer forming material (intermediate layer forming material) is formed over the RGB pixels by vapor deposition, whereby a 1 nm thick hole transport layer (common hole transport layer ( An intermediate layer)) was formed.

  Here, α-NPD, which is a low-molecular hole transport material, was used as the hole transport layer formation material (intermediate layer formation material).

  <7> Next, a light emitting functional layer forming material (second light emitting functional layer) having a thickness of 20 nm was formed by depositing a material for forming a light emitting functional layer across the RGB pixels by vapor deposition.

  Here, the material for forming the light emitting functional layer is obtained by doping 90 parts by mass of CBP (4,4′-bis (9-dicarbazoyl) -2,2′-biphenyl) with 10 parts by mass of FIrpic. Moreover, drying was performed by drying under reduced pressure for 10 minutes at a vacuum degree of 5 Pa or less.

<8> Next, Alq ₃ was deposited on the second light emitting functional layer by a vacuum deposition method to form an electron transport layer having a thickness of 20 nm.

  <9> Next, on the electron transport layer, lithium fluoride (LiF) was formed by a vacuum vapor deposition method to form an electron injection layer having a thickness of 1 nm.

<10> Next, Al was formed into a film by the vacuum evaporation method on the electron injection layer. Thereby, a cathode having a thickness of 200 nm made of Al was formed.
Through the above steps, a light emitting device having RGB pixels (first to third light emitting elements) was manufactured.

(Example 2)
As a material for forming the hole transport layer (second hole transport layer) of the B pixel, α-NPD that is a low-molecular hole transport material and TFB (poly (9, 9-dioctyl-fluorene-co-N- (4-butylphenyl) -diphenylamine)) is used in the same manner as in Example 1 except that a mixed material (mixing ratio is 50:50 by mass) is used. The device was manufactured.

(Example 3)
Example 1 described above except that after the application of the light emitting functional layer forming ink in the RG pixel and the hole transport layer forming ink in the B pixel, the drying and baking were performed collectively. A light emitting device was manufactured in the same manner as described above.

Example 4
Example 2 described above, except that after the application of the ink for forming the light emitting functional layer in the RG pixel and the application of the ink for forming the hole transport layer in the B pixel, these drying and baking were performed collectively. A light emitting device was manufactured in the same manner as described above.

(Example 5)
A light emitting device in the same manner as in Example 1 except that 3-phenoxytoluene was used as a solvent for each of the light emitting functional layer forming ink used for the RG pixel and the hole transport layer forming ink used for the B pixel. Manufactured.

(Example 6)
A light emitting device in the same manner as in Example 2 except that 3-phenoxytoluene was used as a solvent for each of the light emitting functional layer forming ink used for the RG pixel and the hole transport layer forming ink used for the B pixel. Manufactured.

(Example 7)
A light emitting device in the same manner as in Example 3 except that 3-phenoxytoluene was used as a solvent for each of the light emitting functional layer forming ink used for the RG pixel and the hole transport layer forming ink used for the B pixel. Manufactured.

(Example 8)
A light emitting device in the same manner as in Example 4 except that 3-phenoxytoluene was used as a solvent for each of the light emitting functional layer forming ink used for the RG pixel and the hole transport layer forming ink used for the B pixel. Manufactured.

Example 9
A light emitting device was manufactured in the same manner as in Example 1 except that the thickness of the common hole transport layer (intermediate layer) was 1.5 nm.

(Example 10)
A light emitting device was manufactured in the same manner as in Example 1 except that the thickness of the common hole transport layer (intermediate layer) was 2 nm.

(Comparative Example 1)
A light emitting device was manufactured in the same manner as in Example 1 except that the thickness of the common hole transport layer (intermediate layer) was 3 nm.

(Comparative Example 2)
A light emitting device was manufactured in the same manner as in Example 1 except that the formation of the common hole transport layer (intermediate layer) was omitted.

2. Evaluation Regarding the light emitting devices of the respective examples and comparative examples manufactured as described above, the lifetimes (LT50) of the light emitting elements of the respective RGB pixels were measured, and compared with the light emitting devices of the respective comparative examples. The light emitting device had an excellent balance between the life of the light emitting elements of the R pixel and the G pixel and the life of the light emitting element of the B pixel, and the life of the light emitting elements of each pixel was good.

  FIG. 7A shows the result of measuring the lifetime of the light emitting element of the G pixel for the light emitting devices of Examples 1, 9, and 10 and Comparative Examples 1 and 2. Moreover, the result of having measured the lifetime of the light emitting element of B pixel about the light-emitting device of Example 1, 10 and Comparative Examples 1 and 2 is shown to Fig.7 (a).

  In addition, the light emitting device of Example 2 had higher light emission efficiency of the G pixel light emitting element than the light emitting device of Example 1.

DESCRIPTION OF SYMBOLS 1 ... Light emitting element 1B ... Light emitting element 1G ... Light emitting element 1R ... Light emitting element 3 ... Anode 3B ... Anode 3G ... Anode 3R ... Anode 4B ... Hole injection layer 4G ... Hole injection layer 4R ... hole injection layer 4a ... ink 5B ... hole transport layer 5G ... hole transport layer 5R ... hole transport layer 5a ... ink 5b ... ink 6B ... light emitting functional layer 6G ... light emission Functional layer 6R ... Light emitting functional layer 6a ... Ink 6b ... Ink 7 ... Hole transport layer 8 ... Electron transport layer 9 ... Electron injection layer 10 ... Cathode 20 ... Circuit board 21 ... Substrate 22 ... Interlayer insulation film 23 Switching element 24 Wiring 31 Partition 32 Resin layer 40 Sealing substrate 100 Light emitting device 100R Subpixel 100G Subpixel 100B Subpixel 200 Inkjet head 231 Semiconductor layer 232 Gate Edge layer 233 ... Gate electrode 234 ... Source electrode 235 ... Drain electrode 1100 ... Personal computer 1102 ... Keyboard 1104 ... Main unit 1106 ... Display unit 1200 ... Mobile phone 1202 ... Operation button 1204 ... Received call Mouth 1206 ... Mouthpiece 1300 ... Digital still camera 1302 ... Case 1304 ... Light receiving unit 1306 ... Shutter button 1308 ... Circuit board 1312 ... Video signal output terminal 1314 ... I / O terminal 1430 ... TV monitor 1440 Personal computer

Claims (10)

A first anode, a common cathode, a first hole transport layer provided between the first anode and the common cathode, and the first hole transport layer between the first hole transport layer and the common cathode. A first light emitting element having a first light emitting functional layer provided in contact with one hole transport layer;
A second anode, the common cathode, a second hole transport layer provided between the second anode and the common cathode, and a gap between the second hole transport layer and the common cathode. A common hole transport layer provided in contact with the second hole transport layer; and a second light emission provided in contact with the common hole transport layer between the common hole transport layer and the common cathode. A second light emitting element having a functional layer,
The common hole transport layer is provided in contact with the first light emitting functional layer between the common cathode and the first light emitting functional layer,
The common hole transport layer has a thickness of 2 nm or less. The first hole transport layer, the first light emitting functional layer, and the second hole transport layer are each formed using a liquid phase process,
The light emitting device according to claim 1, wherein the common hole transport layer and the second light emitting functional layer are each formed by using a vapor phase process. The first hole transport layer is formed using a polymer hole transport material,
3. The light emitting device according to claim 1, wherein each of the second hole transport layer and the common hole transport layer is configured using a low-molecular hole transport material.   4. The light emitting device according to claim 1, wherein the second hole transport layer includes a material having the same or similar characteristics as the constituent material of the common hole transport layer. 5.   The light emitting device according to any one of claims 1 to 4, wherein the constituent material of the common hole transport layer has an electron blocking property.   The light emitting device according to any one of claims 1 to 5, wherein a constituent material of the first light emitting functional layer is formed using a low molecular material as a main material.   The light emitting device according to claim 1, wherein the common hole transport layer has a thickness of 1 nm or less. A third hole transport layer provided between the third anode, the common cathode, the third anode, and the common cathode, and between the third hole transport layer and the common cathode. A third light emitting element having a third light emitting functional layer provided in contact with the third hole transport layer,
The common hole transport layer is also in contact with the third light emitting functional layer,
The light emitting device according to any one of claims 1 to 7, wherein the first light emitting element, the second light emitting element, and the third light emitting element have different emission colors. The emission color of the first light emitting element is red,
The emission color of the second light emitting element is blue,
The light emitting device according to claim 8, wherein an emission color of the third light emitting element is green.   An electronic apparatus comprising the light emitting device according to claim 1.

Images