JP2002083684A - Light-emitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light-emitting device which is bright and cheap at low power consumption. SOLUTION: The light-emitting device which can convert energy from a triplet excitation state into light emission, is obtained by using an organic compound (polynuclear complex) with a molecular structure, which is easy to generate a mutual interaction of spin to orbit, as the light-emitting layer of the EL device, or a dopant. At this time, using the central metal of the polynuclear complex as cheap metals (for example, Cu, Ni, Co, V, Mn, Fe, Zn, or the like) reduces manufacturing cost, and it becomes possible to provide the low-cost light-emitting device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an EL (El
element (hereinafter, referred to as E) sandwiching a thin film (hereinafter, referred to as an organic EL film) made of an organic compound capable of obtaining ectro luminescence.
L element). In particular, the present invention relates to a light-emitting device using an organic compound capable of converting energy when returning from a triplet excited state to a ground state (hereinafter, triplet excited energy) into light emission.

[0002]

2. Description of the Related Art An EL device using an organic EL film is a device that emits light when an electric field is applied, and is used as a device for a next-generation flat panel display because of its characteristics such as light weight, DC low voltage drive, and high-speed response. Attention has been paid.
In addition, it is considered to be effective as a display screen of a portable device because of its light emission and wide viewing angle.

In an EL element, electrons injected from a cathode and holes injected from an anode recombine at the emission center of an organic EL film to form excitons, and energy is generated when the excitons return to a ground state. It emits and emits light. The excited states include a singlet excited state (S ^* ) and a triplet excited state (T ^* ), and their statistical generation probabilities are considered to be S ^* : T ^* = 1: 3.

[0004] However, general organic compounds emit light (phosphorescence) from a triplet excited state (T ^* ) at room temperature.
Is not observed, the theoretical limit value of the internal quantum efficiency is 2
It was 5%. Further, not all generated light is emitted to the outside of the device, and some light cannot be extracted due to the refractive index inherent in the device. The proportion of the generated light that can be extracted to the outside of the device is called light extraction efficiency, and the extraction efficiency is said to be about 20%.

Therefore, even if all the injected carriers generate excitons, the ratio of the light that can be finally extracted (external quantum efficiency) is 25% × 20% = 5% in consideration of the light extraction efficiency. Become. That is, even if it is assumed that all carriers are recombined, only 5% of the carriers can be extracted as light.

However, recently, an organic compound capable of converting triplet excitation energy into light emission (phosphorescent light emission) has been proposed, and its high luminous efficiency has attracted attention. The following report is an example of using triplet excitons to improve external quantum efficiency.

(1) T. Tsutsui, C. Adachi, S. Saito, Ph
otochemical Processes in Organized Molecular Syste
ms, ed.K. Honda, (Elsevier Sci. Pub., Tokyo, 1991) p.
437. (2) MABaldo, DFO'Brien, Y. You, A. Shoustikov,
S. Sibley, METhompson, SRForrest, Nature 395
(1998) p.151. (3) MABaldo, S.Lamansky, PEBurrrows, METho
mpson, SRForrest, Appl. Phys. Lett., 75 (1999) p. 4. (4) T. Tsutsui, M.-J. Yang, M. Yahiro, K. Nakamura,
T.Watanabe, T.tsuji, Y.Fukuda, T.Wakimoto, S.Mayagu
chi, Jpn.Appl.Phys., 38 (12B) (1999) L1502.

[0008] The organic compound described in the above article is an example in which external quantum efficiency is improved by converting triplet excitation energy into light emission. Some of them well exceed the above-mentioned theoretical limit of external quantum efficiency of 5%. All of these are metal complexes having platinum as a central metal as a third transition series element (hereinafter referred to as platinum complex).
Alternatively, a metal complex having iridium as a central metal (hereinafter, referred to as “metal complex”)
Iridium complex).

Further, when layers composed of an iridium complex and layers composed of a known fluorescent dye, DCM, are alternately laminated, the triplet excitation energy generated by the iridium complex moves to the DCM, and the emission center of the DCM is excited. Is indirectly converted into light emission. The emission of DCM is emission from a singlet excited state (emission of fluorescence), but there is an advantage in that the triplet excitation energy of an iridium complex generated efficiently can be converted to singlet excitation energy of DCM.

As described above, an EL device using an organic compound capable of changing triplet excitation energy into light emission has a higher external quantum efficiency than that of a conventional device. If the external quantum efficiency is high, the emission luminance is also improved. Therefore, an EL element using an organic compound capable of changing triplet excitation energy into light emission will occupy a large weight in future development as a means for achieving high luminance emission. It is believed that.

However, since platinum or iridium is an expensive metal, a metal complex using them is also expensive, and it is expected that cost reduction will be adversely affected in the future. Considering the effect of the metal complex containing a heavy metal on the human body, a material that is as safe as possible and easy to dispose of is preferable as the central metal.

The emission color of the above-mentioned iridium complex is green, and the emission color of the platinum complex is orange, which is a wavelength located in the middle of the visible light range, and red or blue with high color purity has not been obtained. . Therefore, considering its use in a full-color flat panel display in the future, an organic compound that has high external quantum efficiency as well as iridium complex and platinum complex and that can obtain red light emission and blue light emission with high color purity is needed. It is expected to be.

From the above, it is indispensable to develop not only existing iridium complexes and platinum complexes but also new organic compounds capable of obtaining phosphorescence.

[0014]

SUMMARY OF THE INVENTION An object of the present invention is to provide an organic compound capable of converting triplet excitation energy into light emission at a lower cost than before. Another object is to provide an organic compound that can convert triplet excitation energy into light emission with higher efficiency than before. Then, it is an object to provide an EL element having high luminous efficiency by using them.

It is another object of the present invention to provide a light emitting device which is bright and consumes less power, and an electric appliance which consumes less power by using an EL element having high luminous efficiency obtained by carrying out the present invention. I do.

[0016]

The present inventors have focused on the heavy atom effect known as photoluminescence (PL).
The heavy atom effect means that the spin-orbit interaction is strengthened by heavy atoms (atoms holding many nuclear loads) introduced into the molecule of the organic compound or in the solvent, and phosphorescence is promoted. Refers to a phenomenon. The nuclear load corresponds to the atomic number, that is, the number of positive charges of the nucleus.

In order to convert the triplet excitation energy into light emission, the present inventor needs to have a strong spin-orbit interaction, and intentionally uses an organic compound having a molecular structure that enhances the spin-orbit interaction. It was considered that an EL device capable of converting triplet excitation energy into light emission was obtained by using a compound. That is, it was considered that triplet excitation energy can be converted to light emission by using an organic compound having a molecular structure capable of generating a heavy atom effect without using a heavy atom as a central metal.

In order to enhance the spin-orbit interaction without using heavy atoms, it is necessary to increase the total nuclear load by increasing the number of central metals, to obtain a molecular structure substantially including heavy atoms, to use a ferromagnetic or anti-magnetic compound. A method of forming a molecular structure exhibiting ferromagnetism and a method of forming a molecular structure using a ferromagnetic metal as a central metal can be given. In particular, a molecular structure exhibiting ferromagnetism or antiferromagnetism is preferable because the strength of spin-orbit interaction can be adjusted by molecular design.

Therefore, in the present invention, a polynuclear complex having a transition element as a central metal (a metal complex having two or more central metals) is used for an EL element as an organic compound having a molecular structure that enhances spin-orbit interaction. It is characterized by.

That is, a polynuclear complex using a metal (specifically, a first transition series element) which is less expensive than platinum or iridium is used as an E complex.
By using as a light emitting layer (a layer made of an organic compound that undergoes recombination) or a dopant dye (a dye added to the light emitting layer and functioning as a light emission center) of the L element,
An EL element having high internal quantum efficiency can be obtained at a lower manufacturing cost than before.

Further, by using a polynuclear complex, the number of heavy atoms can be increased more practically than a conventional mononuclear complex using heavy atoms (platinum or iridium). As a result, the spin-orbit interaction is strengthened and the It is also possible to improve the internal quantum efficiency.

By using a polynuclear complex, the same or different metals can be present in one metal complex. In other words, the combination of the central metals enables a molecular structure that could not be achieved with the mononuclear complex, and the central metal and ligand of the metal complex that emits phosphorescence can be selected in a wider range.

For example, by introducing nickel, which is a ferromagnetic metal, into a metal complex which originally obtains phosphorescence such as a metal complex having platinum as a central metal, light emission from a triplet excited state can be easily obtained. there is a possibility. In addition, there is a possibility that the transition probability from the triplet excited state to the singlet excited state may be increased by the introduction of nickel, whereby the luminous efficiency of phosphorescence may be increased more than before.

In the case of a polynuclear complex, the state of excitation energy changes depending on the combination of the central metal. In triplet excitation by a metal complex, the central metal is in a triplet excited state by receiving triplet excitation energy generated by the ligand,
May emit phosphorescence. Therefore, the emission color of phosphorescence can be changed by changing the excitation energy state depending on the combination of the central metal.

Further, in the case of the polynuclear complex, it is also possible to design a metal complex in which a central metal is bound by a covalent bond.
The present inventor believes that the presence of a metal in a cluster state in a metal complex can cause a heavy atom effect.

Further, the polynuclear complex has a structure in which the ligand forms a chelate and surrounds the central metal in many cases, and has an advantage that a three-dimensional molecular structure (stable molecular structure) can be easily obtained. Such a three-dimensional structure (also referred to as a steric hindrance) has an effect of suppressing the interaction between molecules, and as a result, the complex is hardly subjected to concentration quenching (a phenomenon in which light emission does not occur due to an increase in concentration). be able to.

As described above, by designing a molecule using a polynuclear complex as a light emitting layer or a dopant dye, the luminous efficiency of the EL device can be increased more than before. Also, the emission color can be controlled by the molecular design of the polynuclear complex. As a result, a light-emitting device that is inexpensive and consumes less power can be obtained.

In this specification, a light emitting device refers to an image display device or a surface light emitting device using an EL element as a light emitting element. Further, a module in which a TAB (Tape Automated Bonding) tape or a TCP (Tape Carrier Package) is attached to a substrate on which an EL element is formed, a module in which a printed wiring board is provided at the tip of the TAB tape or TCP, or a COG (Chip On Chip). Glas
s) All the modules in which an IC (integrated circuit) is directly mounted on a substrate on which an EL element is formed by the method are included in the light emitting device.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION The organic compound disclosed in the present invention capable of converting triplet excitation energy into light emission can be represented by the following molecular formula.

The organic compounds represented by the following molecular formulas (1) to (5) are polynuclear complexes containing the same or different two metal atoms (particularly, when they contain two metal atoms, they are also referred to as dinuclear complexes). These have the advantage of simple synthesis.

The general formula of the metal complex containing two different metal elements as central metals is represented by the following molecular formulas (1) to (3).
The general formula of a metal complex containing two metal elements of the same kind as the central metal is represented by the following molecular formulas (4) and (5).

[0032]

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In the organic compound represented by the above-mentioned molecular formula (1), R1 and R2 are a hydrogen atom, an alkyl group or a substituent containing a benzene nucleus (phenyl group or an aryl group containing a substituent). But it is good.
A1 and A2 are a linear substituent containing nitrogen, oxygen, carbon or sulfur or a heterocyclic group containing a hetero atom, and may be different or the same. M1 and M2 are transition elements, which may be different or the same. Here, n is an integer of n = 2 or more.

[0034]

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In the organic compound represented by the above-mentioned molecular formula (2), R1 and R2 are a hydrogen atom, an alkyl group or a substituent containing a benzene nucleus, and may be different or the same. A1 to A4 are chain substituents containing nitrogen, oxygen, carbon or sulfur, or heterocyclic groups containing hetero atoms, and may be different or the same. M1 and M2 are transition elements, which may be different or the same. Here, n is an integer of n = 2 or more.

[0036]

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In the organic compound represented by the above formula (3), R1 to R4 are a hydrogen atom, an alkyl group or a substituent containing a benzene nucleus, and may be different or the same. R1 and R2 or R3 and R4 may be bonded to each other to form a ring. M1 and M2 are a divalent metal atom or a monovalent metal atom containing a covalent bond, an ionic bond or a coordination bond with an element belonging to groups 15 to 17 of the periodic table, and may be different or the same. Here, n is an integer of n = 2 or more.

[0038]

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In the organic compound represented by the above formula (4), R1 and R2 are a substituent having a carbon atom bonded in a chain (particularly a substituent containing a carbonyl group) or a substituent having a benzene nucleus. However, they may be different or the same. A1 and A2 are an amino group or a heterocyclic group containing a hetero atom (typically, a heterocyclic group containing nitrogen, oxygen or sulfur), which may be different or the same. M is a divalent metal atom or a divalent or higher valent metal atom containing a covalent bond, an ionic bond or a coordinate bond with an element belonging to Groups 15 to 17 of the periodic table.
Here, n is an integer of n = 2 or more.

[0040]

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In the organic compound represented by the above formula (5), R1 and R2 are a hydrogen atom, an alkyl group or a substituent containing a benzene nucleus, and may be different or the same. A1 and A2 are a linear substituent containing nitrogen, oxygen, carbon or sulfur or a heterocyclic group containing a hetero atom, and may be different or the same.
M is a transition element. Here, n is an integer of n = 2 or more.

In addition to the above organic compounds, polynuclear complexes having a covalent bond between central metals can also be used as the organic compound of the present invention.

When the same metal is used as the central metal represented by M1 or M2, Co (II), Ni (I
I) or Cu (II) may be used. Note that, in the organic compounds represented by the molecular formulas (4) and (5), the same can be said for the central metal represented by M.

When a different kind of metal is used as the central metal represented by M1 or M2, the following combinations are possible.

[0045]

[Table 1]

The organic compounds of the present invention described above can be made less expensive than conventional ones by using an inexpensive metal as the central metal. In addition, the EL device using the organic compound of the present invention can have higher luminous efficiency than the conventional device. Therefore, the light-emitting device of the present invention using the organic compound of the present invention for an EL element can be a light-emitting device with low power consumption.

[0047]

[Example 1] In this example, a polynuclear complex represented by the molecular formula (1) in the embodiment of the present invention will be specifically exemplified.

First, the organic compound represented by the following molecular formula (6) is a binuclear complex using tetravalent vanadium (V (IV)) and divalent copper (Cu (II)) as central metals. Ferromagnetic action is acting between metal atoms. Also, since the nuclear load of vanadium is 23 and the nuclear load of copper is 29,
The total nuclear load of the organic compound represented by the molecular formula (6) is 5
Equivalent to 2. Therefore, it is considered that the effect of ferromagnetism can be expected over the heavy atom effect, whereby the spin-orbit interaction is strengthened, and the efficiency of converting triplet excitation energy into light emission is improved.

[0049]

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The organic compound represented by the following molecular formula (7) is a dinuclear complex using divalent manganese (Mn (II)) and divalent cobalt (Co (II)) as central metals.
Since the nuclear load of manganese is 25 and the nuclear load of cobalt is 27, the total nuclear load of the organic compound represented by the molecular formula (7) corresponds to 52. Thereby, it is considered that the heavy atom effect occurs, the spin-orbit interaction is strengthened, and the efficiency of converting triplet excitation energy into light emission is improved.

[0051]

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Example 2 In this example, the polynuclear complex represented by the molecular formula (2) in the embodiment of the present invention will be specifically exemplified.

The organic compound represented by the following molecular formula (8) is a dinuclear complex using divalent iron (Fe (II)) and divalent copper (Cu (II)) as central metals. Since the nuclear load of iron is 26 and the nuclear load of copper is 29, the total nuclear load of the organic compound represented by the molecular formula (8) is equivalent to 55. Thereby, it is considered that the heavy atom effect occurs, the spin-orbit interaction is strengthened, and the efficiency of converting triplet excitation energy into light emission is improved.

[0054]

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Example 3 In this example, the polynuclear complex represented by the molecular formula (3) in the embodiment of the present invention will be specifically exemplified.

The organic compound represented by the following molecular formula (9) is a dinuclear complex using divalent zinc (Zn (II)) and divalent nickel (Ni (II)) as central metals. Since the nuclear load of zinc is 30 and the nuclear load of nickel is 28, the total nuclear load of the organic compound represented by the molecular formula (9) is equivalent to 58. Thereby, it is considered that the heavy atom effect occurs, the spin-orbit interaction is strengthened, and the efficiency of converting triplet excitation energy into light emission is improved.

[0057]

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Example 4 In this example, the polynuclear complex represented by the molecular formula (4) in the embodiment of the present invention will be specifically exemplified.

The organic compound represented by the following molecular formula (10) is a binuclear complex using two divalent copper (Cu (II)) as a central metal, and an antiferromagnetic action acts between metal atoms. ing. Further, since the nuclear load of copper is 29, the total nuclear load of the organic compound represented by the molecular formula (10) is 58.
Is equivalent to Therefore, it is considered that the spin-orbit interaction is strengthened by the antiferromagnetism and the heavy atom effect, and the efficiency of converting triplet excitation energy into light emission is improved.

[0060]

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Example 5 In this example, the polynuclear complex represented by the molecular formula (5) in the embodiment of the present invention will be specifically exemplified.

The organic compound represented by the following molecular formula (11) has two trivalent manganese (Mn (II)
It is a binuclear complex using (I)). Since the nuclear load of manganese is 25, the total nuclear load of the organic compound represented by the molecular formula (11) is equivalent to 50. Thereby, it is considered that the heavy atom effect occurs, the spin-orbit interaction is strengthened, and the efficiency of converting triplet excitation energy into light emission is improved.

[0063]

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Example 6 The organic compounds represented by the molecular formulas (1) to (5) described in the embodiment of the invention and the organic compounds represented by the molecular formulas (6) to (11) described in Example 1 to Example 5 The organic compound represented can be used as a light emitting layer, a hole transport layer, an electron transport layer, or a dopant dye in an EL device.

The organic compound of the present invention has a low lowest unoccupied molecular orbital (LUMO) level and a highest occupied molecular orbital (HOM).
O) In the case of a metal complex having a high level, that is, a metal complex having a narrow energy gap, it is effective to use the metal complex as a light-emitting layer, and light emission in this case is likely to be light on a long wavelength side.
FIG. 1 shows a band diagram when the organic compound of the present invention is used as a light emitting layer. In FIG. 1, 101 is an anode, 102 is a cathode, 10
3 is a hole transport layer (HTL), 104
Denotes a light emitting layer (Emitting Layer: EML), and 105 denotes an electron transport layer (Electron Transfer Layer: ETL).

When the organic compound of the present invention has a hole transporting property, it is effective to use it as a hole transporting light emitting layer. In that case, the electron transporting layer having a low HOMO level is replaced with a hole blocking layer. The recombination probability in the hole transport layer can be increased by using. FIG. 2 shows a band diagram when the organic compound of the present invention is used as a hole-transporting light-emitting layer. In FIG. 2, reference numeral 201 denotes an anode, 202 denotes a cathode, 203 denotes a light emitting layer having a hole transporting property, and 204 denotes an electron transporting layer.

When the organic compound of the present invention has an electron transporting property, it is effective to use it as a light emitting layer having an electron transporting property. In this case, a hole transporting layer having a high LUMO level is used as an electron blocking layer. Thereby, the recombination probability in the electron transport layer can be increased. FIG. 3 shows a band diagram when the organic compound of the present invention is used as an electron-transporting light-emitting layer. In FIG. 3, reference numeral 301 denotes an anode, 302 denotes a cathode, 303 denotes an electron transporting light emitting layer, and 304 denotes a hole transporting layer.

Further, the organic compound of the present invention does not have a carrier transporting property, and the HOMO level is H of the carrier transporting layer.
The LUMO level higher than the OMO level is L in the carrier transport layer.
When it is lower than the UMO level, it is effective to use it as a dopant dye. The carrier transport layer added as a dopant dye may be a hole transport layer or an electron transport layer. Further, it can be added to the light emitting layer.

FIG. 4 shows a band diagram when the organic compound of the present invention is added to the hole transport layer. In FIG. 4, 401 is an anode, 402 is a cathode, 4
03 is a hole transport layer, 404 is a dopant dye (Dopant) added inside the hole transport layer 403, 405 is a hole blocking layer (HBL), and 406 is an electron transport layer.

Note that by adding a dopant dye to the electron transport layer 406 to adjust the thickness of the hole blocking layer 405, light emission can be performed in both the hole transport layer 403 and the electron transport layer 406. It is possible.

In this embodiment, any one or more of the organic compounds represented by the above-mentioned molecular formulas (1) to (5) can be used as the organic compound of the present invention. Of course, any of the organic compounds shown in Examples 1 to 5 may be used.

[Embodiment 7] In this embodiment, a light emitting device including an EL element using the organic compound of the present invention will be described. FIG. 5 is a cross-sectional view of an active matrix light emitting device using the organic compound of the present invention. Here, a thin film transistor (hereinafter referred to as TFT) is used as an active element.
However, a MOS transistor may be used.

Further, a top gate type TFT is used as the TFT.
(Specifically, a planar type TFT) is exemplified, but a bottom gate type TFT (typically, an inverted stagger type TFT) may be used.

In FIG. 5, reference numeral 501 denotes a substrate, and here, a substrate that transmits visible light is used. Specifically, a glass substrate, a quartz substrate, a crystallized glass substrate, or a plastic substrate (including a plastic film) may be used. Note that the substrate 501 also includes an insulating film provided on the surface of the substrate.

On the substrate 501, a pixel portion 511 and a drive circuit 512 are provided. Here, first, the pixel unit 5
11 will be described.

The pixel portion 511 is a region for displaying an image, has a plurality of pixels, and each pixel has a TFT (hereinafter, referred to as a current control TFT) 502 and an EL element 510 for controlling a current flowing through the EL element. Is provided. Although only the current control TFT 502 is shown here, a TFT (hereinafter, referred to as a switching TFT) for controlling a voltage applied to the gate of the current control TFT is provided.

Further, as the current control TFT 502, a p-channel TFT is preferably used here. Although it is possible to use an n-channel TFT, when a current control TFT is connected to the anode of the EL element as in the structure of FIG. 5, the p-channel TFT can reduce power consumption. However, the switching TFT (not shown) may be an n-channel TFT or a p-channel TFT.

The pixel electrode 503 is electrically connected to the drain of the current control TFT 502. Here, the work function of the material of the pixel electrode 503 is 4.5 to 4.5.
Since a 5.5 eV conductive material is used, the pixel electrode 503 is used.
Functions as an anode of the EL element 510. Pixel electrode 50
Typically, indium oxide, tin oxide, zinc oxide, or a compound thereof may be used as 3.

The EL layer 50 is formed on the pixel electrode 503.
4 are provided. Note that, in this specification, an EL layer is a laminate including an organic compound or an inorganic compound included in a structure of an EL element, and a light-emitting layer includes a hole injection layer, a hole transport layer, a hole blocking layer, and an electron injection layer. , A generic name of a layer in which an organic compound or an inorganic compound functioning as an electron transport layer or an electron blocking layer is laminated. However,
The EL layer includes a case where the light-emitting layer is a single layer. In this embodiment, the organic compound of the present invention is used as a light emitting layer or a dopant dye in an EL layer.

Next, a cathode 505 is provided on the EL layer 504. The work function of the material of the cathode 505 is 2.
A conductive material of 5 to 3.5 eV is used. As the cathode 505, typically, a conductive film containing an element belonging to Group 1 or 2 of the periodic table or an aluminum alloy stacked therewith may be used.

The EL element 510 including the pixel electrode 503, the EL layer 504, and the cathode 505 has a protective film 506.
Covered with. The protective film 506 is provided to protect the EL element 510 from oxygen and water. Protective film 506
As the material, a silicon nitride film, a silicon nitride oxide film, an aluminum oxide film, a tantalum oxide film, or a carbon film (specifically, a diamond-like carbon film) is used.

Next, the drive circuit 512 will be described.
The drive circuit 512 is an area for controlling the timing of signals (gate signal and data signal) transmitted to the pixel portion 511, and includes a shift register, a buffer, a latch, an analog switch (transfer gate), or a level shifter. Here, the basic units of these circuits are an n-channel TFT 507 and a p-channel TFT
2 shows a CMOS circuit composed of FT508.

The circuit configuration of the shift register, buffer, latch, analog switch (transfer gate) or level shifter may be a known one. In FIG. 5, the pixel portion 511 and the driving circuit 51 are provided on the same substrate.
2, but without the drive circuit 512, IC or L
It is also possible to electrically connect the SI.

In this case, the current control TFT 502 has E
Although the anode of L element 510 is electrically connected, EL
A structure in which the cathode of the element is electrically connected to the current control TFT may be employed. In that case, the pixel electrode is connected to the cathode 505.
And the cathode may be formed of the same material as the pixel electrode 503. In that case, the current control TF
T is preferably an n-channel TFT.

Here, FIG. 6 shows an external view of the active matrix type light emitting device shown in FIG. FIG.
6A is a top view, and FIG. 6B is a cross-sectional view taken along line AA ′ of FIG. 6A. In addition, reference is made to the reference numerals in FIG.

In FIG. 6A, reference numeral 601 denotes a pixel portion;
02 is a gate signal side drive circuit, and 603 is a data signal side drive circuit. Further, signals transmitted to the gate signal side driving circuit 602 and the data signal side driving circuit 603 are supplied to the input wiring 604 via TAB (Tape Automated Bonding).
Input from the tape 605. Although not shown, T
Instead of the AB tape 605, a TCP (Tape Carrier Package) provided with an IC (integrated circuit) may be connected to the TAB tape.

At this time, reference numeral 606 denotes a cover member provided above the EL element 510 shown in FIG. 5, and is adhered by a sealing member 607 made of resin. Cover material 60
The material 6 may be any material as long as it does not transmit oxygen and water. Here, the cover material 606 is the same as that in FIG.
As shown in (B), a plastic material 606a, and carbon films (specifically, diamond-like carbon films) 606 provided on the front and back surfaces of the plastic material 606a
b, 606c.

Further, as shown in FIG. 6B, the sealing material 607 is covered with a sealing material 608 made of resin so that the EL element 510 is completely sealed in the sealed space 609. At this time, the sealed space 609 is filled with an inert gas (typically, nitrogen gas or a rare gas), a resin, or an inert liquid (typically, liquid fluorinated carbon represented by perfluoroalkane). Good. Further, it is also effective to provide a moisture absorbent or oxygen scavenger.

Further, a polarizing plate may be provided on the display surface (surface on which an image is observed) of the light emitting device shown in this embodiment. This polarizing plate has an effect of suppressing reflection of light incident from the outside and preventing an observer from being reflected on the display surface. Generally, a circularly polarizing plate is used. However, in order to prevent the light emitted from the EL layer from being reflected by the polarizing plate and returned to the inside, it is preferable to adjust the refractive index to have a structure with less internal reflection.

Note that the EL included in the light emitting device of this embodiment is
The device includes the organic compound of the present invention (molecular formulas (1) to (1)
Any of the organic compounds (1)) may be used.
It is also possible to implement in combination with the configuration of the sixth embodiment.

[Embodiment 8] In this embodiment, a light emitting device including an EL element using the organic compound of the present invention will be described. FIG. 7 is a cross-sectional view of a passive matrix light emitting device using the organic compound of the present invention.

In FIG. 7A, reference numeral 701 denotes a substrate, which is made of a plastic material here. Examples of plastic materials include polyimide, polyamide, acrylic resin, epoxy resin, PES (polyethylene sulfil), P
C (polycarbonate), PET (polyethylene terephthalate) or PEN (polyethylene naphthalate) can be used in the form of a plate or a film.

Reference numeral 702 denotes a scanning line (anode) made of an oxide conductive film. In this embodiment, an oxide conductive film obtained by adding gallium oxide to zinc oxide is used. Reference numeral 703 denotes a data line (cathode) made of a metal film. In this embodiment, a bismuth film is used. Reference numeral 704 denotes a bank made of an acrylic resin, which functions as a partition for dividing the data line 703. A plurality of scanning lines 702 and data lines 703 are both formed in a stripe shape and provided to be orthogonal to each other. Although not shown in FIG. 7A, an EL layer is interposed between the scanning line 702 and the data line 703, and an intersection indicated by 705 is a pixel.

Then, the scanning line 702 and the data line 70
Reference numeral 3 is connected to an external drive circuit via a TAB tape 707. Note that reference numeral 708 denotes a wiring group including the scanning lines 702, and reference numeral 709 denotes a wiring group including a set of connection wirings 706 connected to the data lines 703.
Although not shown, instead of the TAB tape 707,
A TCP provided with an IC may be connected to the TAB tape.

In FIG. 7B, reference numeral 710 denotes a sealing material, and 711 denotes a plastic material 7 by the sealing material 710.
01 is a cover material attached to the cover material. As the sealant 710, a photocurable resin may be used, and a material which has little outgassing and low hygroscopicity is preferable. As the cover material, the same material as the substrate 701 is preferable, and glass (including quartz glass) or plastic can be used.
Here, a plastic material is used.

The area indicated by reference numeral 712 shows the structure of the pixel, and an enlarged view of this area is shown in FIG. 713
Denotes an EL layer, which is formed by appropriately combining a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, or an electron injection layer. Of course, a single light emitting layer may be used. At this time, the organic compound of the present invention may be used for the light emitting layer.

Note that, as shown in FIG.
4, the width of the lower layer is smaller than the width of the upper layer,
The data line 703 is physically divided.

The pixel portion 7 surrounded by the sealing material 710
Reference numeral 14 denotes a structure that is shielded from the outside air by a sealing material 715 made of resin to prevent the EL layer from deteriorating.

In the light emitting device of the present invention having the above structure, the pixel portion 714 is formed by the scanning line 702, the data line 703, the bank 704, and the EL layer 713. Can be.

Further, a polarizing plate may be provided on the display surface (surface on which an image is observed) of the light emitting device shown in this embodiment. This polarizing plate has an effect of suppressing reflection of light incident from the outside and preventing an observer from being reflected on the display surface. Generally, a circularly polarizing plate is used. However, in order to prevent the light emitted from the EL layer from being reflected by the polarizing plate and returned to the inside, it is preferable to adjust the refractive index to have a structure with less internal reflection.

Note that the EL included in the light emitting device of this embodiment was
The device includes the organic compound of the present invention (molecular formulas (1) to (1)
Any of the organic compounds (1)) may be used.
It is also possible to implement in combination with the configuration of the sixth embodiment.

[Embodiment 9] In this embodiment, an example in which a printed wiring board is provided in the light emitting device shown in Embodiment 8 to form a module will be described.

The module shown in FIG. 8A has a substrate 10 (a pixel portion 11, wirings 12a and 12b) on which an EL element is formed.
TAB tape 13 is attached to the
A printed wiring board 14 is attached via a B tape 13. Here, a functional block diagram of the printed wiring board 14 is shown in FIG.

As shown in FIG. 8B, at least I / O ports (also referred to as input or output units) 15 and 18 and a data signal side driving circuit 1 are provided inside the printed wiring board 14.
6 and IC functioning as gate signal side drive circuit 17
Is provided.

As described above, a module having a configuration in which the TAB tape is attached to the substrate having the pixel portion formed on the substrate surface, and the printed wiring board having a function as a driving circuit is attached via the TAB tape, In the specification, the module will be referred to as a drive circuit external type module.

Note that the EL included in the light emitting device of this embodiment is
The device includes the organic compound of the present invention (molecular formulas (1) to (1)
Any of the organic compounds (1)) may be used.
It is also possible to implement in combination with the configuration of the sixth embodiment.

[Embodiment 10] In this embodiment, an example in which a printed wiring board is provided in the light emitting device shown in Embodiment 7 or 8 to form a module will be described.

The module shown in FIG. 9A includes a substrate 20 (a pixel portion 21, a data signal side driving circuit 22, a gate signal side driving circuit 23, a wiring 22a,
3a), a TAB tape 24 is attached, and a printed wiring board 25 is attached via the TAB tape 24. Here, a functional block diagram of the printed wiring board 25 is shown in FIG.

As shown in FIG. 9B, at least an IC functioning as I / O ports 26 and 29 and a control unit 27 is provided inside the printed wiring board 25. Although the memory unit 28 is provided here,
It is not necessary. Also, the control unit 27
This is a part having a function for controlling a drive circuit, correcting image data, and the like.

A module having a structure in which a printed wiring board having a function as a controller is attached to a substrate on which an EL element is formed as described above will be particularly referred to as an externally attached controller module in this specification.

The EL included in the light emitting device of this embodiment is
The device includes the organic compound of the present invention (molecular formulas (1) to (1)
Any of the organic compounds (1)) may be used.
It is also possible to implement in combination with the configuration of the sixth embodiment.

[Embodiment 11] The light emitting device of the present invention has advantages that it is bright, consumes low power, and has high reliability. Therefore, it can be used as a light source of various electric appliances.

Typically, it can be used as a light source used as a backlight or a front light of a liquid crystal display device or a light source of a lighting device.

Note that the EL included in the light emitting device of this embodiment is
The device includes the organic compound of the present invention (molecular formulas (1) to (1)
Any of the organic compounds (1)) may be used.
It is also possible to implement in combination with the configuration of the sixth embodiment.

[Embodiment 12] The light emitting device of the present invention is of a self-luminous type, so that it has better visibility in a bright place than a liquid crystal display device and has a wide viewing angle. Therefore, it can be used as a display portion of various electric appliances.

Examples of the electric appliance of the present invention include a video camera, a digital camera, a goggle type display (head mounted display), a navigation system, an audio device, a notebook personal computer, a game device, and a wireless portable device (mobile computer, mobile phone,
A portable game machine or an electronic book), an image reproducing apparatus provided with a recording medium, and the like. Fig. 1 shows their specific examples.
0, shown in FIG.

FIG. 10A shows an EL display.
A housing 2001, a support base 2002, and a display unit 2003 are included. The light emitting device of the present invention can be used for the display portion 2003. Since the EL display is a self-luminous type, it does not require a backlight and can be a display portion thinner than a liquid crystal display.

FIG. 10B shows a video camera, which includes a main body 2101, a display section 2102, an audio input section 2103, operation switches 2104, a battery 2105, and an image receiving section 210.
6 inclusive. The light emitting device of the present invention can be used for the display portion 2102.

FIG. 10C shows a digital camera, which includes a main body 2201, a display section 2202, an eyepiece section 2203, and operation switches 2204. The light emitting device according to the present invention has a display unit 22.
02 can be used.

FIG. 10D shows an image reproducing apparatus provided with a recording medium, including a main body 2301, a recording medium (CD, LD, DVD, or the like) 2302, operation switches 2303, a display section (a) 2304, and a display section (b). ) 2305. The display unit (a) mainly displays image information, and the display unit (b) mainly displays character information. The light emitting device of the present invention can be used for these display units (a) and (b). In addition,
The image reproducing device provided with the recording medium includes a CD reproducing device, a game machine, and the like.

FIG. 10E shows a portable (mobile) computer, which includes a main body 2401, a display portion 2402, an image receiving portion 2403, operation switches 2404, and a memory slot 24.
05. The electro-optical device of the invention can be used for the display portion 2402. This portable computer can record information on a recording medium in which a flash memory or a nonvolatile memory is integrated, and can reproduce the information.

FIG. 10F shows a personal computer, which includes a main body 2501, a housing 2502, a display portion 2503,
A keyboard 2504 is included. The light-emitting device of the present invention can be used for the display portion 2503.

If the emission luminance of the EL material becomes higher in the future, it becomes possible to enlarge and project the light containing the output image information with a lens or the like and use it for a front-type or rear-type projector.

[0124] The above-mentioned electric appliances are available on the Internet or C
Information distributed through an electronic communication line such as an ATV (cable television) or wireless communication such as radio waves is often displayed, and in particular, the opportunity to display moving image information is increasing. Since the response speed of the EL material is very high, it is suitable for displaying such a moving image.

In the light emitting device, since the light emitting portion consumes power, it is desirable to display information so that the light emitting portion is reduced as much as possible. Therefore, when a light emitting device is used for a portable information terminal, particularly a display portion mainly for character information such as a mobile phone or an in-vehicle audio, the character information is driven by a light emitting portion with a non-light emitting portion as a background. It is desirable to do.

FIG. 11A shows a portable telephone, which includes a main body 2601, an audio output unit 2602, and an audio input unit 260.
3, including a display unit 2604, operation switches 2605, and an antenna 2606. The light emitting device of the present invention can be used for the display portion 2604. Note that the display portion 2604 can display power of the mobile phone by displaying white characters on a black background.

FIG. 11B shows an audio device (specifically, an audio system for a vehicle).
702, and operation switches 2703 and 2704. The light-emitting device of the present invention can be used for the display portion 2702.
In this embodiment, the in-vehicle audio is shown, but it may be used for home audio. Note that the display portion 2704 can suppress power consumption by displaying white characters on a black background.

Further, it is effective to provide a function of modulating the light emission luminance in accordance with the brightness of the use environment by providing a built-in optical sensor and a means for detecting the brightness of the use environment. The user can recognize the image or the character information without any problem if the brightness of the contrast ratio of 100 to 150 can be secured as compared with the brightness of the use environment. In other words, if the usage environment is bright, increase the brightness of the image to make it easier to see,
When the usage environment is dark, it is possible to suppress the power consumption by suppressing the brightness of the image.

The electric appliance of this embodiment may use a light emitting device having any of the structures of the seventh to tenth embodiments. Further, even when the display portion of the electric appliance shown in this embodiment is entirely a liquid crystal display, the light emitting device of the present invention can be used as a backlight or front light of the liquid crystal display.

[0130]

According to the present invention, a light emitting device which is bright and consumes less power can be obtained at low cost. Further, by using such a light-emitting device as a light source or a display portion, an electric appliance having a bright display portion and low power consumption can be obtained at low cost.

[Brief description of the drawings]

FIG. 1 is a diagram showing a band diagram of an EL element.

FIG. 2 is a diagram showing a band diagram of an EL element.

FIG. 3 is a diagram showing a band diagram of an EL element.

FIG. 4 is a diagram showing a band diagram of an EL element.

FIG. 5 illustrates a cross-sectional structure of a light-emitting device.

FIG. 6 illustrates a top structure and a cross-sectional structure of a light-emitting device.

FIG. 7 illustrates a top structure and a cross-sectional structure of a light-emitting device.

FIG. 8 illustrates a structure of a light-emitting device.

FIG. 9 illustrates a structure of a light-emitting device.

FIG. 10 illustrates a specific example of an electric appliance.

FIG. 11 illustrates a specific example of an electric appliance.

Claims (7)

[Claims] 1. A light emitting device including an EL element, wherein the EL element includes a thin film made of an organic compound having a structure represented by the following molecular formula (1). Embedded image (However, R1 and R2 are a hydrogen atom, an alkyl group or a substituent containing a benzene nucleus, and they may be different or the same, respectively. A1 and A2 are a linear substituent containing nitrogen, oxygen, carbon or sulfur, or It is a heterocyclic group containing a hetero atom, which may be different or the same.
M1 and M2 are transition elements, which may be different or the same. Here, n is an integer of n = 2 or more. ) 2. A light emitting device including an EL element, wherein the EL element includes a thin film made of an organic compound having a structure represented by the following molecular formula (2). Embedded image (R1 and R2 are a hydrogen atom, an alkyl group or a substituent containing a benzene nucleus, which may be different or the same, and A1 to A4 are a linear substituent or a heteroatom containing nitrogen, oxygen, carbon or sulfur. And each of the heterocyclic groups may be different or the same.
And M2 are transition elements, each of which may be different or the same. Here, n is an integer of n = 2 or more. ) 3. A light emitting device including an EL element, wherein the EL element includes a thin film made of an organic compound having a structure represented by the following molecular formula (3). Embedded image (R1 to R4 are a hydrogen atom, an alkyl group, or a substituent containing a benzene nucleus, and each may be different or the same. R1 and R2 or R3 and R4 may be bonded to each other to form a ring. Also, M1 and M2
Is a transition element, which may be different or the same. Here, n is an integer of n = 2 or more. ) 4. A light emitting device including an EL element, wherein the EL element includes a thin film made of an organic compound having a structure represented by the following molecular formula (4). Embedded image (R1 and R2 are a substituent having a carbon atom bonded in a chain or a substituent containing a benzene nucleus, and each may be different or the same. A1 and A2 are a heterocyclic group containing an amino group or a hetero atom. And M may be different or the same, and M is a transition element, and n is an integer of n = 2 or more.) 5. A light-emitting device including an EL element, wherein the EL element includes a thin film made of an organic compound having a structure represented by the following molecular formula (5). Embedded image (R1 and R2 are a hydrogen atom, an alkyl group or a substituent containing a benzene nucleus, which may be different or the same, and A1 and A2 are a linear substituent containing nitrogen, oxygen, carbon or sulfur, or a heteroatom. And a heterocyclic group which may be different or the same.
M is a transition element. Here, n is an integer of n = 2 or more. ) 6. A light emitting device including an EL element, wherein the EL element includes a thin film made of a polynuclear complex having a covalent bond between central metals. 7. An electric appliance using the light emitting device according to claim 1. Description: