JP2007258253A - Transistor material and light-emitting transistor element using the same - Google Patents

Abstract

【選択図】なしAn object of the present invention is to provide a light-emitting transistor material which has excellent characteristics of both light emission and mobility when used as a light-emitting transistor element.
A light-emitting transistor element using a specific organic compound light emission represented by the following chemical formula (1) in a light-emitting layer of the transistor element is provided.
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Description

  The present invention relates to a material that can be used for a light-emitting transistor element and a light-emitting transistor element using the material.

  The light emitting transistor element is a composite device in which an organic transistor has a light emitting function. An element using a light emitting transistor element can be made compact with fewer parts compared to a conventional device having a transistor part and a light emitting part separately. In addition, since it can be expected to improve luminous efficiency, it is currently attracting much attention.

  As materials that can be used for the light-emitting transistor, for example, non-patent document 1 reports tetracene, and non-patent document 2 uses oligothiophene or polyphenylene vinylene.

Appl. Phys. Lett. 2005, 86, 141106. Science, 2000, 290, 963.

  However, these materials have low light emission characteristics and low charge mobility, and further improvements are required.

  Therefore, an object of the present invention is to provide a light-emitting transistor material that has good characteristics of both light emission and mobility when used as a light-emitting transistor element.

  As a result of intensive studies by the present inventors, it was found that a light emitting transistor element having very high light emission and charge mobility can be obtained by using a compound having a specific skeleton as a transistor material, and the present invention has been achieved.

（式（１）中、Ａｒ^１及びＡｒ^２は、それぞれ、芳香族炭化水素基、又は芳香族複素環基を示す。
上記芳香族炭化水素基及び芳香族複素環基は、それぞれ、上記のＲ^１やＲ^２以外に、置換基を有してもよいアルキル基、置換基を有してもよいアルコキシ基、置換基を有してもよい芳香族炭化水素基、置換基を有してもよい芳香族複素環基、置換基を有してもよいアリールオキシ基、置換基を有してもよいアミノ基、シアノ基、ニトロ基、ハロゲン原子を置換基として有してもよい。また、上記のアルキル基、アルコキシ基、芳香族炭化水素基、芳香族複素環基、アリールオキシ基、及びアミノ基が有してもよい置換基は、アルキル基、アルコキシ基、ハロゲン原子から選ばれる。
上記Ｒ^１及びＲ^２は、それぞれ、水素原子、置換基を有してもよいアルキル基、置換基を有してもよいアルコキシ基、置換基を有してもよいカルボキシ基、置換基を有してもよいアシル基、置換基を有してもよいスルファニル基、置換基を有してもよいシクロアルキル基、置換基を有してもよい芳香族炭化水素基、置換基を有してもよい芳香族複素環基、置換基を有してもよいアルケニル基、置換基を有してもよいアルキニル基、置換基を有してもよいアリールオキシ基、シアノ基から選ばれる基を表す。さらに、上記Ｒ^１及びＲ^２が有してもよい置換基は、アルキル基、アルコキシ基、ハロゲン原子から選ばれる。
上記のｎ個のベンゼン環は、それぞれ置換基を有してもよく、ベンゼン環の置換基同士が結合して環を形成していてもよい。このベンゼン環が有してもよい置換基は、アルキル基、アルコキシ基、アルキル基で置換されていてもよいアミノ基、アルケニル基、スルファニル基である。
さらに、ｎは、２〜６の整数を示す。） That is, this invention exists in the light emitting transistor element containing the transistor material characterized by following formula (1), and this transistor material.

(In formula (1), Ar ¹ and Ar ² each represent an aromatic hydrocarbon group or an aromatic heterocyclic group.
In addition to the above R ¹ and R ² , the aromatic hydrocarbon group and the aromatic heterocyclic group are an alkyl group that may have a substituent, an alkoxy group that may have a substituent, and a substituent. An aromatic hydrocarbon group which may have a substituent, an aromatic heterocyclic group which may have a substituent, an aryloxy group which may have a substituent, an amino group which may have a substituent, cyano You may have a group, a nitro group, and a halogen atom as a substituent. In addition, the substituent that the alkyl group, alkoxy group, aromatic hydrocarbon group, aromatic heterocyclic group, aryloxy group, and amino group may have is selected from an alkyl group, an alkoxy group, and a halogen atom. .
R ¹ and R ² each have a hydrogen atom, an alkyl group that may have a substituent, an alkoxy group that may have a substituent, a carboxy group that may have a substituent, or a substituent. An acyl group which may have a substituent, a sulfanyl group which may have a substituent, a cycloalkyl group which may have a substituent, an aromatic hydrocarbon group which may have a substituent, and a substituent Represents a group selected from an aromatic heterocyclic group which may have a substituent, an alkenyl group which may have a substituent, an alkynyl group which may have a substituent, an aryloxy group which may have a substituent, and a cyano group . Furthermore, the substituent that R ¹ and R ² may have is selected from an alkyl group, an alkoxy group, and a halogen atom.
The n benzene rings may each have a substituent, and the substituents of the benzene ring may be bonded to each other to form a ring. The substituent that the benzene ring may have is an alkyl group, an alkoxy group, an amino group that may be substituted with an alkyl group, an alkenyl group, or a sulfanyl group.
Furthermore, n shows the integer of 2-6. )

  Since the transistor material of the present invention has high carrier mobility, it is very effective as a transistor material. Further, when the transistor material of the present invention is used, the crystallinity is improved, and the characteristics of both light emission and mobility of the obtained light-emitting transistor element can be improved.

The present invention will be described in detail below.
The present invention relates to a transistor material comprising a compound represented by the following formula (1). This compound has high carrier mobility, and can be used as a transistor material when used in a device using an organic semiconductor such as an organic field effect transistor. Since the compound used in the present invention has a light emitting property, it can also be used as a light emitting transistor material for a light emitting transistor element.

式（１）中、Ａｒ^１、Ａｒ^２、Ｒ^１及びＲ^２は、後述する基である。さらに、ｎは、２〜６の整数を示し、好ましくは２又は３である。

In the formula (1), Ar ¹ , Ar ² , R ¹ and R ² are groups described later. Furthermore, n shows the integer of 2-6, Preferably it is 2 or 3.

The compound represented by the above formula (1) will be described.
(Ar ¹ and Ar ² )
Ar ¹ and Ar ² each represent an aromatic hydrocarbon group or an aromatic heterocyclic group. The aromatic hydrocarbon group and the aromatic heterocyclic group are each an alkyl group that may have a substituent, an alkoxy group that may have a substituent, in addition to the above R ¹ and R ² , An aromatic hydrocarbon group which may have a substituent, an aromatic heterocyclic group which may have a substituent, an aryloxy group which may have a substituent, an amino group which may have a substituent , A cyano group, a nitro group, and a halogen atom may be substituted. In addition, the substituent that the alkyl group, alkoxy group, aromatic hydrocarbon group, aromatic heterocyclic group, aryloxy group, and amino group may have is selected from an alkyl group, an alkoxy group, and a halogen atom. .

  The aromatic hydrocarbon group is preferably an aromatic hydrocarbon, and examples include a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group (preferably a 2-naphthyl group), an anthryl group (preferably a 2-anthryl group). ), Phenanthryl group, fluorenyl group, phenylethenophenyl group and the like, and these may have a substituent. Among these, an aromatic hydrocarbon group having 14 or less carbon atoms is particularly preferable. This is because if the number of carbon atoms is too large, it is not preferable in order to give the molecules orientation. These may have a substituent.

  Examples of the aromatic heterocyclic group include pyridyl group, pyrazyl group, bipyridyl group, phenylpyridyl group, pyridinophenyl group, furyl group, thienyl group, bitienyl group, tertienyl group, pyrrolidyl group, imidazole group, benzimidazole group, Oxazole group, indole group, benzoxazole group, thiazole group, benzothiazole group, benzothiazolyl group, benzofuryl group, benzoxazolyl group, pyrrolyl group, pyridazyl group, pyrazinyl group, pyrimidyl group, thienyl group, bithienyl group, phenylthienyl group Benzothienyl group, quinolyl group and the like, and these may have a substituent. Among these, an aromatic heterocyclic group having 12 or less carbon atoms is particularly preferable. This is because if the number of carbon atoms is too large, it is not preferable in order to give the molecules orientation. These may have a substituent.

  Examples of the alkyl group include straight-chain or branched alkyl groups having 1 to 20 carbon atoms. Specific examples include a methyl group, an ethyl group, an n-propyl group, a 2-propyl group, and an n-butyl group. , An isobutyl group, a tert-butyl group, a hexyl group, an octyl group, a dodecyl group, an octadecyl group, and the like, and these may have a substituent.

  Examples of the cycloalkyl group include a cyclohexyl group and a cycloheptyl group, and these may have a substituent.

  Examples of the alkoxy group include ethoxy group, propoxy group, butoxy group, heptoxy group, hexyloxy group, octyloxy group and the like, and these may have a substituent.

  As the aromatic hydrocarbon group and aromatic heterocyclic group having the above-mentioned aromatic hydrocarbon group and aromatic heterocyclic group as substituents, the same groups as described above can be used.

  Examples of the aryloxy group include a phenoxy group and a biphenyloxy group, and these may have a substituent.

  Examples of the amino group include a hexylmethylamino group, a dioctylamino group, a dihexylamino group, and the like, and these may have a substituent.

  Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

Specific examples of the substituent that the alkyl group, alkoxy group, aromatic hydrocarbon group, aromatic heterocyclic group, aryloxy group, and amino group may have include an alkyl group having 1 to 20 carbon atoms, Examples thereof include any group selected from an alkoxy group having 1 to 20 carbon atoms and a halogen atom. Specific examples of each of these groups are the same as the examples of the groups in Ar ¹ and Ar ² described above.

The above Ar ¹ and Ar ² may be the same or different, but it is preferable that they are the same because it is easy to control the molecular arrangement and an improvement in mobility can be expected.

In particular, from the viewpoint of carrier mobility and light emission, Ar ¹ and Ar ² are each preferably an aromatic hydrocarbon which may have a substituent, and particularly preferably a benzene ring.

(R ¹ and R ² )
R ¹ and R ² each have a hydrogen atom, an alkyl group that may have a substituent, an alkoxy group that may have a substituent, a carboxy group that may have a substituent, or a substituent. An acyl group which may have a substituent, a sulfanyl group which may have a substituent, a cycloalkyl group which may have a substituent, an aromatic hydrocarbon group which may have a substituent, and a substituent Represents a group selected from an aromatic heterocyclic group which may have a substituent, an alkenyl group which may have a substituent, an alkynyl group which may have a substituent, an aryloxy group which may have a substituent, and a cyano group . Furthermore, the substituent that R ¹ and R ² may have is selected from an alkyl group, an alkoxy group, and a halogen atom.

The alkyl group, alkoxy group, aromatic hydrocarbon group, aromatic heterocyclic group and aryloxy group are the alkyl group, alkoxy group, cycloalkyl group, aromatic hydrocarbon group used in the above Ar ¹ and Ar ² , A group similar to an aromatic heterocyclic group or an aryloxy group can be used.

  Examples of the carboxy group include an octyl carboxy group and a hexyl carboxy group, and these may have a substituent.

  Examples of the acyl group include an acetyl group, and these may have a substituent.

  Examples of the sulfanyl group include an octylsulfanyl group and a hexylsulfanyl group, and these may have a substituent.

  Examples of the alkenyl group include a vinyl group, a phenyl-substituted vinyl group, an ethyl-substituted vinyl group, a biphenyl-substituted vinyl group, an allyl group, and a 1-butenyl group, and these may have a substituent.

  Examples of the alkynyl group include an ethynyl group, a phenyl-substituted ethynyl group, a trimethylsilyl-substituted ethynyl group, and a propargyl group, and these may have a substituent.

Specific examples of the substituent that R ¹ and R ² may have include any group selected from an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, and a halogen atom. It is done. Specific examples of each of these groups are the same as the examples of the groups in Ar ¹ and Ar ² described above.

The above R ¹ and R ² may be the same or different, but it is preferable that they are the same because it is easy to control the molecular arrangement and an improvement in mobility can be expected.

(N benzene rings)
The n benzene rings of the above formula (1) may each have a substituent, and the substituents of the benzene ring may be bonded to form a ring. Examples of the substituent that the benzene ring may have include an alkyl group, an alkoxy group, an amino group optionally substituted with an alkyl group, an alkenyl group, and a sulfanyl group.

(Specific examples of the compound represented by the formula (1))
Specific examples of the compound represented by the formula (1) include specific examples <1 (a)> to <4> shown in FIGS. 1A to 1F show specific examples in the case where n is 2 or 3, Ar ¹ = Ar ² , and R ¹ = R ² . 2 (a) to 2 (b), when n is 2 or 3 and all of Ar ¹ , Ar ² , R ¹ and R ² are different, Ar ¹ and Ar ² are different from each other, R ^In the case where ¹ and R ² are the same, Ar ¹ and Ar ² are the same, and specific examples in any case where R ¹ and R ² are different are shown. In FIG. 1 to FIG. 4, “Me-” represents a methyl group.

Further, FIGS. 3A to 3C and FIG. 4 show the case where n in the formula (1) is 2, and two phenyl groups can form a 5-membered ring or a 6-membered ring via a substituent. The example in the case of the compound connected so that it may form newly is shown. Examples of the compound in which n in formula (1) is 2 and two phenyl groups are linked to form a new 5-membered ring or 6-membered ring via a substituent are shown below. Examples thereof include compounds represented by the formulas (1-1) to (1-7) (“Me” in the formula (1-6) represents a methyl group). 3A to 3C show specific examples in the case of Ar ¹ = Ar ² and R ¹ = R ² . FIG. 4 also shows that when Ar ¹ , Ar ² , R ¹ and R ² are all different, Ar ¹ and Ar ² are different, and R ¹ and R ² are the same, Ar ¹ and Ar ² are The specific example in the case where they are the same and R ¹ and R ² are different is shown.

(Molecular weight of compound represented by formula (1), application)
The molecular weight of the compound represented by the formula (1) (including formulas (1-1) to (1-7)) is preferably 350 or more, more preferably 400 or more, and more preferably 500 or more. Also, it is preferably 5000 or less, more preferably 3000 or less, more preferably 2000 or less, and particularly preferably 1500 or less. By setting the molecular weight within this range, a characteristic that the compound has stability can be exhibited.

  The compound represented by the above formula (1) (including formulas (1-1) to (1-7)) can be used as a transistor material. The transistor material using the compound represented by the above formula (1) (including formulas (1-1) to (1-7)) has not only high carrier mobility but also high emission characteristics. In particular, it can be used as a light emitting transistor material.

(Light-emitting transistor element)
Next, a light-emitting transistor element using the compound of the above formula (1) (including formulas (1-1) to (1-7)) will be described.
Examples of the light-emitting transistor element include an element having a basic structure of a field effect transistor (FET) as shown in FIG.

The light-emitting transistor element 10 is capable of transporting holes and electrons as carriers, and emits light by recombination of holes and electrons. The light-emitting layer 1 includes the above pyrene-based compound as a main constituent, and the light-emitting layer 1 Opposite to the hole injection electrode for injecting holes into the so-called source electrode 2, the electron injection electrode for injecting electrons into the light emitting layer, the so-called drain electrode 3, and the source electrode 2 and drain electrode 3, the light emitting layer 1 It is composed of a gate electrode 4 made of an N ⁺ silicon substrate for controlling the distribution of carriers inside. The gate electrode 4 may be composed of a conductive layer made of an impurity diffusion layer formed in the surface layer portion of the silicon substrate.

  Specifically, as shown in FIG. 5, an insulating film 5 made of silicon oxide or the like is provided on the gate electrode 4, and the source electrode 2 and the drain electrode 3 are provided on the insulating film 5 with a gap therebetween. The light emitting layer 1 is provided so as to cover the source electrode 2 and the drain electrode 3 and to enter between the two electrodes.

  At this time, in order to improve the carrier mobility, it is preferable to process the silicon substrate after forming the insulating film 5 or after forming the source electrode 2 and the drain electrode 3. There are two types of silicon substrate processing methods: surface treatment and substrate temperature control.

  The surface treatment is a method in which after the formation of the insulating film 5 or after the formation of the source electrode 2 and the drain electrode 3, UV ozone treatment is performed and a surface treatment agent is applied. As this surface treating agent, generally known surface treating agents such as HMDS (hexamethyldisilazane) and OTS (octyltrichlorosilane) can be used. After applying the surface treatment agent, the residue of the surface treatment agent is removed, and the compound used for the light emitting layer is evaporated under vacuum.

  The temperature of the silicon substrate is controlled by vacuum deposition of the compound used for the light-emitting layer after the insulating film 5 is formed or the substrate after the formation of the source electrode 2 and the drain electrode 3 is heated at a constant temperature in a vacuum state. It is a method to do. The lower limit of the temperature range of the substrate is preferably 40 ° C. Further, the upper limit of the temperature range of the substrate is preferably 100 ° C, more preferably 80 ° C. Note that both the surface treatment and the substrate temperature control may be performed.

  In order for the element to exhibit the function of a light-emitting transistor, the difference between the HOMO energy level and the LUMO energy level of the organic phosphor constituting the light-emitting layer 1, particularly the pyrene-based compound that is the main component, carrier mobility Or, it is preferable that the luminous efficiency satisfies a predetermined range. In addition, when the said pyrene type compound which has said each characteristic is used, it becomes possible to make each function higher by adding subcomponents, such as said dopant.

  First, the smaller the difference between the HOMO energy level and the LUMO energy level, the more easily electrons move and light emission and semiconductivity (that is, electron or hole conductivity in one direction) are more likely to occur. ,preferable. Specifically, it is preferably 5 eV or less, more preferably 3 eV or less, and even more preferably 2.7 eV or less. In addition, since this difference is so preferable that it is small, the minimum of this difference is 0 eV.

Further, the higher the carrier mobility is, the higher the semiconducting property is. Specifically, it is preferably 1.0 × 10 ⁻⁵ cm ² / V · s or more, more preferably 4.0 × 10 ⁻⁵ cm ² / V · s or more, and 1.0 × 10 ⁻⁴ cm ² / s. V · s or more is more preferable. Note that the upper limit of the carrier mobility is not particularly limited, and is approximately 1 cm ² / V · s.

  The luminous efficiency refers to the ratio of light generated by inserting photons and electrons, and the ratio of emitted light energy to injected optical energy is referred to as PL luminous efficiency (or PL quantum efficiency), and injected electrons. The ratio of the number of emitted photons to the number of photons is called EL luminous efficiency (or EL quantum efficiency).

  The injected and excited electrons emit light by recombining with holes, but this recombination does not necessarily occur with a probability of 100%. For this reason, when comparing the organic compound which comprises the said light emitting layer 1, by comparing EL luminous efficiency, the ratio of the light energy discharge | release amount with respect to the injected light energy, and the ratio of the recombination of an electron and a hole The synergistic effects can be compared. By comparing the PL emission efficiency, it is possible to compare the ratio of the amount of emitted light energy to the injected light energy. By comparing both the PL emission efficiency and the EL emission efficiency, the electron and It is also possible to compare the rate of recombination with holes.

  The PL luminous efficiency is preferably as the light emission level is large, preferably 20% or more, and more preferably 30% or more. Note that the upper limit of the PL luminous efficiency is 100%.

Further, the EL luminous efficiency is preferably as the degree of light emission is larger, preferably 1 × 10 ⁻³ % or more, and more preferably 5 × 10 ⁻³ % or more. Note that the upper limit of the EL luminous efficiency is 100%.

  In addition to the above, the light emitting transistor element 10 is characterized by the wavelength of emitted light. This wavelength is within the range of visible light, but has a wavelength that varies depending on the type of organic phosphor used, particularly the pyrene compound. Various colors can be developed by combining organic phosphors having different wavelengths. For this reason, the wavelength of the emitted light exhibits its characteristics.

Moreover, since the light emitting transistor element 10 is characterized by light emission, it should have a certain level of light emission luminance. This light emission luminance refers to the amount of light emission corresponding to the brightness of an object that humans feel when looking at the object. In the measurement method using a photocounter, the emission luminance is preferably as high as possible, preferably 1 × 10 ⁴ CPS (count per sec) or more, preferably 1 × 10 ⁵ CPS or more, and more preferably 1 × 10 ⁶ CPS or more.

  The light-emitting layer 1 is formed by vapor-depositing (or co-depositing when there are a plurality of types) organic phosphors constituting the light-emitting layer 1. The thickness of the light emitting layer may be at least about 70 nm.

  The source electrode 2 and the drain electrode 3 are electrodes for injecting holes and electrons into the light emitting layer 1 and are formed of gold (Au), magnesium-gold alloy (MgAu), or the like. The two are formed so as to face each other with a minute gap of 0.4 to 50 μm or the like. Specifically, for example, as illustrated in FIG. 6, the source electrode 2 and the drain electrode 3 are formed to have comb-shaped portions 2 a and 3 a each composed of a plurality of comb teeth, and the comb teeth of the source electrode 2 are formed. The comb-teeth constituting the shape portion 2a and the comb-teeth constituting the comb-teeth shape portion 3a of the drain electrode 3 are alternately arranged at predetermined intervals, thereby making the function as the light-emitting transistor element 10 more efficient. Can be demonstrated.

The distance between the source electrode 2 and the drain electrode 3 at this time, that is, the comb-shaped portion 2a and the comb
The interval between the tooth-shaped portions 3a is preferably 50 μm or less, preferably 3 μm or less, and more preferably 1 μm or less. If it exceeds 50 μm, sufficient semiconductor properties cannot be exhibited.

  The light emitting transistor element 10 is configured to move both holes and electrons within the light emitting layer 1 by applying a voltage to the source electrode 2 and the drain electrode 3 and to recombine both in the light emitting layer 1. Luminescence can be produced. At this time, the amount of holes and electrons moving between the two electrodes through the light emitting layer 1 depends on the voltage applied to the gate electrode 4. For this reason, by controlling the voltage applied to the gate electrode 4 and the change thereof, the conduction state between the source electrode 2 and the drain electrode 3 can be controlled. Since the light emitting transistor element 10 performs P-type driving, a negative voltage is applied to the drain electrode 3 with respect to the source electrode 2, and a negative voltage is applied to the gate electrode 4 with respect to the source electrode 2. .

  Specifically, by applying a negative voltage to the gate electrode 4 with respect to the source electrode 2, holes in the light emitting layer 1 are attracted to the gate electrode 4 side, and holes in the vicinity of the surface of the insulating film 5 are attracted. The density becomes high. When the voltage between the source electrode 2 and the drain electrode 3 is appropriately set, holes are injected from the source electrode 2 to the light emitting layer 1 depending on the control voltage applied to the gate electrode 4, and electrons are injected from the drain electrode 3 to the light emitting layer 1. Will be injected. That is, the source electrode 2 functions as a hole injection electrode, and the drain electrode 3 functions as an electron injection electrode. Thereby, in the light emitting layer 1, recombination of a hole and an electron arises and light emission accompanying this will arise. This light emission state can be turned on / off or the light emission intensity can be changed by changing the control voltage applied to the gate electrode 4.

  The theory that the above recombination of holes and electrons can be explained as follows. By applying a negative voltage to the gate electrode 4 with respect to the source electrode 2, a hole channel 11 is formed in the light emitting layer 1 near the interface of the insulating film 5, as shown in FIG. The pinch-off point 12 reaches the vicinity of the drain electrode 3. Then, a high electric field is formed between the pinch-off point 12 and the drain electrode 3 and n, and the energy band is greatly bent as shown in FIG. As a result, electrons in the drain electrode 3 cause an FN (Fowler-Nordheim) tunnel effect that penetrates the potential barrier between the drain electrode 3 and the light emitting layer 1, and are injected into the light emitting layer 1 to recombine with holes. Is done.

  In addition to the theory that the recombination of holes and electrons is due to the above-described FN tunnel effect, the following theory is also possible. That is, as shown in FIG. 7C, the electrons at the HOMO energy level of the organic phosphor in the light emitting layer 1 are excited to the LUMO energy level by a high electric field, and the excited electrons are positive in the light emitting layer 1. Recombine with the hole. At the same time, electrons are injected from the drain electrode 3 to make up for the HOMO energy level vacated by excitation to the LUMO energy level.

  A plurality of the light emitting transistor elements 10 are two-dimensionally arranged on the substrate 20 to constitute the display device 21. An electric circuit diagram of the display device 21 is shown in FIG. That is, in this display device 21, the light emitting transistor elements 10 as described above are arranged in pixels P11, P12,..., P21, P22,. Is selectively emitted, and the light emission intensity (luminance) of the light emitting transistor element 10 of each pixel is controlled to enable two-dimensional display. The substrate 20 may be, for example, a silicon substrate in which the gate electrode 4 is integrated. That is, the gate electrode 4 may be constituted by a conductive layer made of an impurity diffusion layer patterned on the surface of the silicon substrate. Further, a glass substrate may be used as the substrate 20.

Since each light emitting transistor element 10 is P-type driven, the drain electrode 3 (D) has a buffer.
The bias voltage Vd (<0) is applied, and the source electrode 2 (S) is set to the ground potential (= 0). A selection transistor Ts for selecting each pixel and a data holding capacitor C are connected in parallel to the gate electrode 4 (G).

  The gates of the selection transistors Ts of the pixels P11, P12,..., P21, P22,... Aligned in the row direction are connected to the common scanning lines LS1, LS2,. In addition, common data lines LD1, LD2,... For each column are provided on the side opposite to the light emitting transistor element 10 in the selection transistors Ts of the pixels P11, P21,. Each is connected.

  For the scanning lines LS1, LS2,..., The pixels P11, P12,...; P21, P22,. A scanning drive signal for selecting pixels at a time is provided. In other words, the scanning line driving circuit 22 sets each row as a sequentially selected row, and conducts the selection transistors Ts of a plurality of pixels in the selected row at a time, thereby bringing the selection transistors Ts of a plurality of pixels in the non-selected row together. Thus, a scanning drive signal for blocking can be generated.

  On the other hand, signals from the data line driving circuit 23 are input to the data lines LD1, LD2,. A control signal corresponding to the image data is input from the controller 24 to the data line driving circuit 23. The data line driving circuit 23 outputs a light emission control signal corresponding to the light emission gradation of each pixel in the selected row at the timing when the plurality of pixels in each row are collectively selected by the scanning line driving circuit 22. Supply to… in parallel.

  As a result, in each pixel in the selected row, a light emission control signal is given to the gate electrode 4 (G) via the selection transistor Ts, so that the light emitting transistor element 10 of the pixel has a gradation corresponding to the light emission control signal. It emits light (or goes out). Since the light emission control signal is held in the capacitor C, the potential of the gate electrode G is held even after the selected row by the scanning line driving circuit 22 moves to another row, and the light emitting state of the light emitting transistor element 10 is held. The In this way, two-dimensional display becomes possible.

Examples The present invention will be described more specifically with reference to examples. However, the present invention is not limited to the description of the following examples unless it exceeds the gist.

Synthesis Example 1 Synthesis of 4,4′-biphenylylene bis (p-butyl) stilbene (Compound 2)

In a 300 mL four-necked flask, 3.7 g (0.02 mol) of p-bromobenzaldehyde, 4.09 g (0.023 mol) of p-butylphenylboronic acid, 4.88 g (0.046 mol) of Na ₂ CO ₃ , 90 mL of toluene Then, 15 mL of ethanol and 15 mL of demineralized water were added, and the system was replaced with nitrogen by bubbling with nitrogen. After adding 1.16 g of tetrakistriphenylphosphine palladium, the mixture was heated and stirred in an oil bath at 80 ° C. for 5 hours under a nitrogen stream. After allowing to cool, 50 mL of demineralized water was added to the reaction solution and the phases were separated, and the organic layer was dehydrated over anhydrous magnesium sulfate and concentrated. Components other than the target compound such as inorganic salt and palladium mixed together by column chromatography (silica gel, hexane: ethyl acetate = 10: 1) were removed to obtain yellowish brown compound 1. The yield was 4.14 g, the yield was 87%, and the LC purity was 80%. The ¹ H-NMR data is as follows.

¹ H-NMR (CDCl ₃ , 400 MHz)... Δ10.05 (s, 1H), 7.94 (d, 2H), 7.74 (d, 2H), 7.563 (d, 2H), 7. 30 (d, 2H.), 2.67 (d, 2H), 1.65 (m, 2H), 1.39 (m, 2H), 0.95 (m, 3H)

A three-way cock connected to a nitrogen line was attached to a 300 mL four-necked flask, and 1.84 g (0.077 mol) of Compound 1 and 1.59 g (0.0035 mol) of tetraethyl (4,4′-biphenylylene dimethylene) biphenylphosphonate. ) And 150 mL of DMF were added and stirred. A solution prepared by dissolving 2.48 g of a NaOCH ₃ (5 mol / l) methanol solution in 12 mL of DMF was added dropwise thereto and reacted at room temperature overnight. This was subjected to suction filtration, and the obtained crystals were heated and washed with 100 mL of toluene and subjected to suction filtration to obtain crude crystals. This was put into a 200 mL eggplant flask, washed with 100 mL methanol for 1 hour, and subjected to suction filtration to obtain yellow crystalline compound 2. The yield was 1.72 g, and the yield was 79% (Mw: 622.88). The ¹ H-NMR data is as follows.

¹ H-NMR (CDCl ₃ , 400 MHz) δ 7.47 (d, 4H), 7.22 (d, 2H), 7.11 (d, 2H), 6.98 (s, 2H), 6. 66 (d, 4H.), 2.99 (s, 12H), 2.96 (m, 1H), 2.58 (m, 2H), 1.32 (d, 6H), 1.1 (d, 12H)

(Synthesis Example 2) Synthesis of (4,4'-biphenylylenebis (p-trifluorostilbene)) (Compound 4)

In a 300 mL four-necked flask, 3.7 g (0.02 mol) of p-bromobenzaldehyde, 4.37 g (0.023 mol) of p-trifluoromethylphenylboronic acid, 4.88 g (0.046 mol) of Na ₂ CO ₃ , Toluene 90 mL, ethanol 35 mL, and demineralized water 15 mL were added, and the system was replaced with nitrogen by bubbling with nitrogen. After adding 1.02 g of tetrakistriphenylphosphine palladium, the mixture was heated and stirred in an oil bath at 80 ° C. for 2.5 hours under a nitrogen stream. After allowing to cool, 100 mL of demineralized water was added to the reaction solution for separation, and the organic layer was dehydrated over anhydrous magnesium sulfate and concentrated. Components other than the target compound such as inorganic salt and palladium mixed together by column chromatography (silica gel, hexane: ethyl acetate = 10: 1) were removed to obtain white compound 1. The yield was 4.43 g, the yield was 89%, and the LC purity was 97%. The ¹ H-NMR data is as follows.

_{^{· 1 H-NMR (CDCl 3}} , 400MHz) ... δ10.09 (s, 1H), 8.00 (d, 2H), 7.77 (d, 2H), 7.75 (s, 4H)

A three-way cock connected to a nitrogen line was attached to a 300 mL four-necked flask, and 2.20 g (0.088 mol) of compound 3 and 1.82 g (0.0035 mol) of tetraethyl (4,4′-biphenylylene dimethylene) biphenylphosphonate were added. ) And 154 mL of DMF were added and stirred. A solution prepared by dissolving 2.48 g of a NaOCH ₃ (5 mol / l) methanol solution in 12 mL of DMF was added dropwise thereto and reacted at room temperature overnight. This was subjected to suction filtration, and the obtained crystals were heated and washed with 100 mL of toluene and subjected to suction filtration to obtain crude crystals. This was put into a 200 mL eggplant flask, washed with 60 mL methanol for 1 hour, and subjected to suction filtration to obtain yellow crystalline compound 4. The yield was 2.35 g, and the yield was 91% (Mw 622.88).

Synthesis Example 3 Synthesis of 4,4′-biphenylylene bis (p-octylstilbene) (Compound 5)

A three-way cock connected to a nitrogen line was attached to a 300 mL four-necked flask, and p-octylbenzaldehyde 1.73 (0.073 mol) and tetraethyl (4,4′-biphenylylene dimethylene) biphenylphosphonate 1.5 g (0.0033 mol) ) And 120 mL of DMF were added and stirred. A solution prepared by dissolving 2.05 g of NaOCH ₃ (5 mol / l methanol solution) in 10 mL of DMF was added dropwise thereto and reacted at room temperature overnight. This was subjected to suction filtration, and the obtained crystals were heated and washed with 100 mL of toluene and subjected to suction filtration to obtain crude crystals. This was put into a 200 mL eggplant flask, washed with 60 mL methanol for 1 hour, and subjected to suction filtration to obtain yellow crystalline compound 5. The yield was 2.35 g, and the yield was 91% (Mw 622.88).

Synthesis Example 4 Synthesis of 4,4′-biphenylylene bis (p-butylstilbene) (Compound 6)

A 300 mL four-necked flask was fitted with a three-way cock connected to a nitrogen line, and butylbenzaldehyde 1.73 (0.073 mol) and tetraethyl (4,4′-biphenylylene dimethylene) biphenylphosphonate 1.5 g (0.0033 mol) DMF120mL was put and stirred. A solution prepared by dissolving 2.05 g of NaOCH ₃ (5 mol / l methanol solution) in 10 mL of DMF was added dropwise thereto and reacted at room temperature overnight. This was subjected to suction filtration, and the resulting crystals were heated and washed with 100 mL of toluene, and suction filtered to obtain yellow crystalline compound 6. The yield was 1.25 g and the yield was 76% (Mw 470.69).

Synthesis Example 5 Synthesis of 4,4′-biphenylylenebisstilbene (Compound 7)

A 300 mL four-necked flask is equipped with a three-way cock connected to a nitrogen line, and 1.73 g (0.077 mol) of benzaldehyde, 1.5 g (0.0035 mol) of tetraethyl (4,4′-biphenylylenediethylene) biphenylphosphonate and 120 mL of DMF And stirred. A solution prepared by dissolving 2.17 g of NaOCH ₃ (5 mol / l methanol solution) in 10 mL of DMF was added dropwise thereto and reacted at room temperature overnight. This was subjected to suction filtration, and the obtained crystals were heated and washed with 100 mL of toluene and suction filtered to obtain yellow crystals of Compound 7. The yield was 1.11 g and the yield was 88% (Mw 358.47).

Synthesis Example 6 Synthesis of 4,4′-biphenylylene bis (p-cyanostilbene) (Compound 8)

A 200 mL four-necked flask was fitted with a three-way cock connected to a nitrogen line, and 1.0 g (0.076 mol) of p-cyanobenzaldehyde and 1.58 g (0.0035 mol) of tetraethyl (4,4′-biphenylylene dimethylene) biphenylphosphonate. ) And 60 mL of DMF were added and stirred. A solution prepared by dissolving 2.15 g of NaOCH ₃ (5 mol / l methanol solution) in 10 mL of DMF was added dropwise thereto and reacted at room temperature overnight. This was subjected to suction filtration, and the obtained crystals were heated and washed with 100 mL of toluene, and suction filtered to obtain yellow crystals of Compound 8. The yield was 1.32 g, and the yield was 69% (Mw 480.49).

Synthesis Example 7 Synthesis of 4,4′-biphenylylenebis (5-octylthiophenylethynylene) (Compound 10)

A 300 mL four-necked flask was equipped with a dropping funnel, a nitrogen line-connected three-way cock, and a low-temperature thermometer, and heat drying and nitrogen substitution were repeated with a heat gun under reduced pressure to create a nitrogen atmosphere in the system. 2-Octylthiophene and 100 mL of dry THF (tetrahydrofuran) were added, and the reactor was cooled to −5 ° C. in an ice bath. 21 mL of n-butyllithium (1.6 mol / l) was dropped from the dropping funnel over 20 minutes, and stirring was continued while maintaining at 25 ° C. in a water bath for 40 minutes after completion of the dropping. At 0 ° C. Dry DMF 3.3mL was dripped from the syringe, and it stirred under cooling conditions for 30 minutes after completion | finish of dripping, Then, the bath for cooling was removed, and it heated up to room temperature, and left still overnight. After slowly adding 80 mL of 1N HCl, 100 mL of toluene was added for liquid separation, and the organic layer was dehydrated with anhydrous magnesium sulfate and concentrated to obtain an orange oil. The solvent (toluene) was included, yield 6.44g, yield 103% (Mw224.36), HPLC purity 84%. The ¹ H-NMR data is as follows.

_{^{· 1 H-NMR (CDCl 3}} , 400MHz) ... δ9.81 (s, 1H), 7.6 (d, 1H), 6.89 (d, 1H), 2.87 (m, 2H), 1. 71 (m, 2H.), 1.28 (m, 10H), 0.88 (m, 3H)

A 300 mL four-necked flask was fitted with a three-way cock connected to a nitrogen line, and 1.18 g (0.053 mol) of 2-formyl-5-octylthiophene (Compound 9) and tetraethyl (4,4′-biphenylylene dimethylene) biphenyl 1.1 g (0.0024 mol) of phosphonate and 95 mL of DMF were added and stirred. A solution prepared by dissolving 0.3 g of NaOCH ₃ (5 mol / l methanol solution) in 5 mL of DMF was added dropwise thereto and reacted at room temperature overnight. This was suction filtered, and the obtained crystals were recrystallized with 50 mL of toluene, and suction filtered to obtain yellow crystals of Compound 10. The yield was 0.88 g, the yield was 62% (Mw 594.96), and the HPLC purity was 92%. The ¹ H-NMR data is as follows.

¹ H-NMR (CDCl ₃ , 400 MHz) δ 7.55 (d, 2H), 7.50 (d, 2H), 7.20 (d, 2H), 6.88 (d, 2H), 6. 86 (s, 1H), 6.67 (d, 2H.), 2.80 (m, 2H), 1.69 (m, 2H), 1.28 (m, 10H), 0.89 (m, 2H)

Synthesis Example 8 Synthesis of 4,4′-biphenylylene bis (p-octyloxystilbene) (Compound 11)

  To a 100 mL three-necked flask equipped with a dropping funnel, a nitrogen line-connected three-way cock, a thermometer, and a rotor, 3.01 g of tetraethyl 4,4′-biphenylylene dimethylenephosphonate (Wako Pure Chemical Reagent), 4-octyloxybenzaldehyde (purity) 90%) 5.38 g was added and the atmosphere was purged with nitrogen, and then 50 mL of DMF (Wako Pure Chemical Reagent) was added and stirred at room temperature. From the dropping funnel, 5 mL of 28% sodium methoxide / methanol solution (Wako Pure Chemical Reagent) was added dropwise over 1 minute, stirred at room temperature for 10 minutes, and then heated and stirred at 50 ° C. for 20 hours in an oil bath. The solid precipitated by the reaction was collected by suction filtration, and the collected solid was washed successively with acetonitrile, chloroform, and acetonitrile, and the solid was dried under heating and reduced pressure to obtain a pale yellow powdered solid. The yield was 3.73 g, and the yield was 91.7%.

(Measurement and calculation of carrier mobility, EL luminous efficiency, PL luminous efficiency)
Carrier mobility, EL luminous efficiency, and PL luminous efficiency were measured and calculated as follows.
[Carrier mobility μ (cm ² / V _s )]
The relational expression between the drain voltage (V _d ) and the drain current of the transistor element is expressed by the following equation [1] and increases linearly (linear region).

Further, when V _d increases, I _d is saturated and becomes a constant value (saturation region) due to the pinch-off of the channel, and I _d is expressed by the following equation [2].

In addition, each code | symbol of said Formula [1] [2] is as follows.
L: Channel length [cm]
W: Channel width [cm]
C _i : capacitance [F / cm ² ] per unit area of the gate insulating film
μ _sat : mobility in saturation region [cm ² / Vs]
I _d : drain current [A]
V _d : drain voltage [V]
V _g : gate voltage [V]
V _T : gate threshold voltage [V] (this means that the drain current (V _dsat ^1/2 ) of the drain current is constant with _respect to the gate voltage (V _g ) under a constant drain voltage (V _d ) in the saturation region And plot the point where the asymptote intersects the horizontal axis.)

From the relationship between I _d ^1/2 and Vg in this saturation region, the mobility (μ) in the transistor element can be obtained.

In the present invention, the drain voltage is changed from 10 V to -100 V in a -1 V step using a semiconductor parameter analyzer (Agilent, HP4155C) under conditions where the pressure is a vacuum degree to 5 × 10 ^-3 Pa and the temperature is room temperature. The gate voltage was operated from 0 V to −100 V in a −20 V step, and the mobility was calculated using the above equation (2).

[EL luminous efficiency]
The EL light emission efficiency η _ext is obtained by operating the drain voltage from 10 V to −100 V in −1 V step, the gate voltage from 0 V to −100 V, and −20 V step by using a transistor element, and emitting light emitted from the element. Measured with a counter (Newport Corp .: 4155C Semiconductor Parameter Analyzer), the photon number [CPS] obtained there was converted into a luminous flux [lw] using the following formula [3], and then EL was used using the following formula [4]. Luminous efficiency η _ext was calculated.

In addition, each code | symbol of said Formula [3] [4] is as follows.
N _PC : Number of photons observed by photon counter (PC) [CPS]
X _PC : Value obtained by converting the number of photons into a luminous flux [lw] r: Radius [cm] of a cone or a circle
h: Distance between photon counter and sample [cm]

(PL luminous efficiency)
The luminous efficiency of PL is determined by using a integrating sphere (IS-060, Labsphere Co.) as excitation light after forming a single layer film by depositing the transistor material of the present invention on a quartz substrate in a nitrogen atmosphere to a thickness of 100 nm. This was calculated by irradiating a 325 nm He-Cd laser (IK5651R-G, Kimoelectric Co.) and measuring light emission multi-channel photodiode (PMA-11, Hamamatsu photonics Co.) from the sample.

Example 1
The light emitting transistor device shown in FIGS. 5 and 6 was manufactured under the following conditions.
Insulating film 5: A 300 nm silicon oxide film was deposited on a silicon substrate to form an insulating film.
Source electrode 2 and drain electrode 3... Each electrode (Au, thickness 40 nm) having a comb-shaped portion composed of 20 comb teeth is formed, and each comb-shaped portion is alternately formed as shown in FIG. It arrange | positioned on the insulating film 5 so that it may distribute | arrange. At this time, a layer (1 nm) made of chromium was provided between the insulating film 5 and both electrodes. At this time, the width of the channel portion (between each comb-shaped portion) was 25 μm and the length was 4 mm.
-Light emitting layer 1 ... The light emitting layer 1 was formed by vapor-depositing the transistor material which consists of the compound 2 manufactured by the said manufacture example 1 so that the surroundings of an insulating film, the source electrode 2, and the drain electrode 3 might be covered.

  With respect to the obtained device, HOMO and LUMO energy levels, EL luminous efficiency, and carrier mobility were measured by the above measurement methods. Further, PL light emission efficiency was measured by the above measurement method using the transistor material composed of Compound 1. The results are shown in Table 1.

(Examples 2 to 4)
A device was prepared in the same manner as in Example 1 except that Compound 5, Compound 6, and Compound 7 produced in the above Production Example were used as the compound used in the light emitting layer. With respect to the obtained device, HOMO and LUMO energy levels, EL luminous efficiency, and carrier mobility were measured by the above measurement methods. Moreover, PL luminous efficiency was measured by the said measuring method using the transistor material which consists of each compound. The results are shown in Table 1.
It was found that the transistor material of the present invention has a very high carrier mobility.

(Examples 5-7)
Elements were obtained in the same manner as in Examples 1 to 4, except that the following operation A (HMDS treatment) was performed. The results are shown in Table 1. It has been found that the carrier mobility is improved by the treatment with the surface treatment agent.
-Operation A (HMDS treatment): The substrate after the source electrode 2 and the drain electrode 3 were formed was subjected to UV ozone treatment, and the surface treatment agent HMDS was applied for 2 minutes. Then, the residue of HMDS was removed with air, and the compound used for the light emitting layer was evaporated under vacuum.

(Comparative Example 1)
A device was prepared in the same manner as in Examples 1 to 3, except that Comparative Compound 1 shown by the following formula (2) was used as the compound for the light emitting layer. With respect to the obtained device, HOMO and LUMO energy levels, EL luminous efficiency, and carrier mobility were measured by the above measurement methods. Moreover, PL luminous efficiency was measured by the said measuring method using the transistor material which consists of the comparative compound 1. The results are shown in Table 1.

Chemical formula showing examples of Ar ¹ , Ar ² , R ¹ , R ² in chemical formula (1) Chemical formula showing examples of Ar ¹ , Ar ² , R ¹ , R ² in chemical formula (1) Chemical formula showing examples of Ar ¹ , Ar ² , R ¹ , R ² in chemical formula (1) Chemical formula showing examples of Ar ¹ , Ar ² , R ¹ , R ² in chemical formula (1) Chemical formula showing examples of Ar ¹ , Ar ² , R ¹ , R ² in chemical formula (1) Chemical formula showing examples of Ar ¹ , Ar ² , R ¹ , R ² in chemical formula (1) Chemical formula showing examples of Ar ¹ , Ar ² , R ¹ , R ² in chemical formula (1) Chemical formula showing examples of Ar ¹ , Ar ² , R ¹ , R ² in chemical formula (1) Chemical formula showing examples of Ar ¹ , Ar ² , R ¹ , R ² in chemical formula (1) Chemical formula showing examples of Ar ¹ , Ar ² , R ¹ , R ² in chemical formula (1) Chemical formula showing examples of Ar ¹ , Ar ² , R ¹ , R ² in chemical formula (1) Chemical formula showing examples of Ar ¹ , Ar ² , R ¹ , R ² in chemical formula (1)

Sectional drawing which shows the example of the light emitting transistor element concerning this invention The top view which shows the structure of a source electrode and a drain electrode (A) (b) (c) The schematic diagram which shows the light emission mechanism of a light emitting transistor element Electrical circuit diagram showing an example of a display device using a light emitting transistor element according to the present invention

DESCRIPTION OF SYMBOLS 1 Light emitting layer 2 Source electrode 2a Comb shape part 3 Drain electrode 3a Comb shape part 4 Gate electrode 5 Insulating film 10 Light emitting transistor element 11 Hole channel 12 Pinch-off point 20 Substrate 21 Display device 22 Scan line drive device 23 Data line drive Device 24 controller

S source electrode D drain electrode
G gate electrode C capacitor Ts selection transistor P11, P12 pixel LS1, LS2 scanning line LD1, LD2 data line

Claims (6)

A transistor material comprising a compound represented by the following formula (1).

(In formula (1), Ar ¹ and Ar ² each represent an aromatic hydrocarbon group or an aromatic heterocyclic group.
In addition to the above R ¹ and R ² , the aromatic hydrocarbon group and the aromatic heterocyclic group are an alkyl group that may have a substituent, an alkoxy group that may have a substituent, and a substituent. An aromatic hydrocarbon group which may have a substituent, an aromatic heterocyclic group which may have a substituent, an aryloxy group which may have a substituent, an amino group which may have a substituent, cyano You may have a group, a nitro group, and a halogen atom as a substituent. In addition, the substituent that the alkyl group, alkoxy group, aromatic hydrocarbon group, aromatic heterocyclic group, aryloxy group, and amino group may have is selected from an alkyl group, an alkoxy group, and a halogen atom. .
R ¹ and R ² each have a hydrogen atom, an alkyl group that may have a substituent, an alkoxy group that may have a substituent, a carboxy group that may have a substituent, or a substituent. An acyl group which may have a substituent, a sulfanyl group which may have a substituent, a cycloalkyl group which may have a substituent, an aromatic hydrocarbon group which may have a substituent, and a substituent Represents a group selected from an aromatic heterocyclic group which may have a substituent, an alkenyl group which may have a substituent, an alkynyl group which may have a substituent, an aryloxy group which may have a substituent, and a cyano group . Furthermore, the substituent that R ¹ and R ² may have is selected from an alkyl group, an alkoxy group, and a halogen atom.
The n benzene rings may each have a substituent, and the substituents of the benzene ring may be bonded to each other to form a ring. The substituent that the benzene ring may have is an alkyl group, an alkoxy group, an amino group that may be substituted with an alkyl group, an alkenyl group, or a sulfanyl group.
Furthermore, n shows the integer of 2-6. )   The transistor material according to claim 1, wherein n in the formula (1) is 2 or 3. The transistor material according to claim 1, wherein Ar ¹ and Ar ^{2 in} the formula (1) are benzene rings which may have a substituent.   A light-emitting transistor material using the transistor material according to claim 1.   A light-emitting layer capable of transporting holes and electrons as carriers and having the light-emitting transistor material according to claim 4 as a main constituent, and emitting light by recombination of holes and electrons, A hole injection electrode for injection; an electron injection electrode for injecting electrons into the light emitting layer; and a gate electrode facing the hole injection electrode and the electron injection electrode and controlling the distribution of carriers in the light emitting layer. Light emitting transistor element.   Each of the hole injection electrode and the electron injection electrode has a comb-shaped portion composed of a plurality of comb teeth, and a comb tooth constituting the comb-shaped portion of the hole injection electrode and a comb of the electron injection electrode The light-emitting transistor element according to claim 5, wherein comb teeth constituting the tooth-shaped portion are alternately arranged with a predetermined interval.

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