KR20080056065A - Buffer layer comprising compounds having diaza spirobifluorene core structure and electronic device comprising the buffer layer - Google Patents

Abstract

A buffer layer including a material of a diaza SPN(spirobifluorene) core structure is provided to improve carrier injection and carrier transportation of an electronic device by including a new buffer material containing as a core a diaza SPN structure in which a nitrogen atom is included in a ring. A buffer layer includes a material having a diaza SPN core structure indicated by the following chemical formula 1, R1 and R2 are independently selected from a group of a substituted or non-substituted alkyl group having a carbon number of 1-30, a substituted or non-substituted heteroalkyl group having a carbon number of 1-30, a substituted or non-substituted alkoxy group having a carbon number of 1-30, a substituted or non-substituted heteroalkoxy group having a carbon number of 1-30, a substituted or non-substituted aryl group having a carbon number of 6-30, a substituted or non-substituted aryl alkyl group having a carbon number of 6-30, a substituted or non-substituted aryloxy group having a carbon number of 6-30, a substituted or non-substituted hetero aryl group having a carbon number of 2-30, a substituted or non-substituted hetero aryl alkyl group having a carbon number of 2-30, a substituted or non-substituted hetero aryl oxy group having a carbon number of 2-30, a substituted or non-substituted cyclo alkyl group having a carbon number of 5-20, a substituted or non-substituted hetero cyclo alkyl group having a carbon number of 2-30, a substituted or non-substituted alkyl ester group having a carbon number of 1-30, a substituted or non-substituted hetero alkyl ester group having a carbon number of 1-30, a substituted or non-substituted aryl ester group having a carbon number of 6-30 and a substituted or non-substituted hetero aryl ester group having a carbon number of 2-30.

Description

Buffer layer including a material having a diaza spirobifluorene core structure and an electronic device comprising the buffer layer TECHNICAL FIELD

1 is an absorbance and PL spectrum of Flu-SPNB-Flu synthesized in Preparation Example 1 of the present invention,

2 is a thermogravimetry analysis graph of Flu-SPNB-Flu synthesized in Preparation Example 1 of the present invention,

Figure 3 is a differential scanning calorimetry (Differential Scanning Calorimetry) graph of Flu-SPNB-Flu synthesized in Preparation Example 1 of the present invention,

4 is a structure of a diode-like device (hole-only device) manufactured in Example 1 of the present invention,

5 is a current-voltage characteristic curve of the diode-like device of Example 1 and Comparative Example 1. FIG.

<Explanation of symbols for the main parts of the drawings>

1: Indium Tin Oxide (ITO)

2: buffer layer

3: organic semiconductor layer

4: Au

Embodiments of the present invention relate to a buffer layer including a material having a diaza spirobifluorene core structure and an electronic device including the buffer layer, and more particularly, to a diaza spirobifluorene having a nitrogen atom included in a ring ( The present invention relates to a buffer layer made of a novel buffer material containing a diaza spirobifluorene (SPN) structure as a core and capable of improving charge injection and charge mobility, and an electronic device including the buffer layer.

Organic material-based device technology is emerging as a new technology to complement the Si-based electronic device in the field of large-area flexible display. OTFT (Organic Thin Film Transistor), in which active research is being conducted, can be considered to have sufficient competitiveness in TFT technology in fields that do not require the integration and performance of Si-based TFTs.

Compared to amorphous Si TFTs, OTFTs cost only 1/3 of the infrastructure cost, and are easier to operate and can be processed continuously compared to organic substrates. In order for OTFT to be applied as a backplane of a display, it is required to improve OTFT characteristics through design and synthesis of organic semiconductors having high mobility, device design, and process technology development.

The characteristics of the TFT are determined by electron or hole injection and movement. Since there is no contact resistance between the electrode and the semiconductor layer, it is ideal that electrons or holes are effectively injected into the channel layer so that the electrons or holes move quickly in the channel layer. Unlike Si-based FETs that are easy to form ohmic contacts, contact resistance is a major cause of OTFT degradation. In general, when a metal contacts a semiconductor layer or a charge transport layer having a low impurity concentration, a resistance barrier is formed because a potential barrier is formed on the contact surface. In principle, the height of the potential barrier is formed according to the state of the junction and the mismatch of energy levels between the electrode and the semiconductor layer or the charge transport layer.

Conventional electrode surface treatment methods used to reduce the contact resistance between the electrode surface and the semiconductor layer or the charge transport layer include the use of a self-assembled monolayer (SAM), the use of a buffer layer. Among them, the buffer layer is a technology for stacking a layer containing a material that reduces contact resistance between an electrode and a semiconductor layer or a charge transport layer, and is mainly applicable to an organic thin film transistor (OTFT) or an organic diode (OELD). .

As such a buffer layer material, a low-molecular semiconductor or poly (3,4-ethylenedioxythiophene) poly (styrene sulfate) (poly (3,4-ethylenedioxythiophene) capable of forming a film by a vacuum process such as triphenyl amine derivatives acid-doped conducting polymers have been used that allow solution processing such as poly (styrenesulfonate).

A buffer layer material is required for solution processing to reduce costs, but acid-doped conducting polymers can be used as buffer layer material when acid-doped conducting polymers are used as the buffer layer material. There is a problem that the diffusion (diffusion) to inhibit the stability of the device. Therefore, there is a continuing need for the development of buffer layer materials that are capable of solution processing and that do not use acid-dopants.

The present invention addresses this technical need, and one aspect of the present invention includes a novel buffer material having a diaza spirobifluorene core structure containing nitrogen atoms in a ring to improve charge injection and mobility. It is about a buffer layer.

Another aspect of the invention relates to an electronic device comprising the buffer layer.

One embodiment of the present invention relates to a buffer layer (buffer layer) including a material having a SPN core structure represented by the following formula (1).

[Formula 1]

Where

R ₁ and R ₂ are each independently a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted heteroalkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms, substituted or unsubstituted Substituted heteroalkoxy group having 1 to 30 carbon atoms, substituted or unsubstituted aryl group having 6 to 30 carbon atoms, substituted or unsubstituted arylalkyl group having 6 to 30 carbon atoms, substituted or unsubstituted aryloxy group having 6 to 30 carbon atoms , Substituted or unsubstituted heteroaryl group having 2 to 30 carbon atoms, substituted or unsubstituted heteroarylalkyl group having 2 to 30 carbon atoms, substituted or unsubstituted heteroaryloxy group having 2 to 30 carbon atoms, substituted or unsubstituted carbon atoms 5-20 cycloalkyl group, substituted or unsubstituted heterocycloalkyl group having 2 to 30 carbon atoms, substituted or unsubstituted alkyl ester group having 1 to 30 carbon atoms, substituted or unsubstituted A is selected from 1 to 30 carbon atoms in the heterocyclic alkyl ester group, a substituted or unsubstituted aryl ester group of a ring having 6 to 30 carbon atoms and a substituted or unsubstituted hetero group, an aryl ester of a ring containing 2 to 30 carbon atoms.

As shown in Formula 1, the buffer material used in the embodiment of the present invention contains a diaza spirobifluorene (SPN) having a conjugated structure in a ring containing a nitrogen atom having a non-covalent electron pair in a ring, ie, a core structure of the material. It contains. Therefore, when the buffer layer including the buffer material is applied to the electrode surface of the electronic device, the electrical properties of the electronic device may be improved by improving charge injection and charge mobility between the electrode and the semiconductor layer or the charge transport layer.

In this case, in Formula 1, R ₁ and R ₂ are each independently a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 carbon atoms, wherein the aryl group or hetero It is preferable that the rings forming the aryl group are fused with each other, and the substituent substituted with the aryl group or the heteroaryl group may be a linear or branched alkyl group having 1 to 10 carbon atoms, a perfluorinated alkyl group, a halogen atom, a hydroxy group, a nitro group, or an amino group. It is preferable that it is at least 1 type selected from the group which consists of a cyano group, an alkoxy group, an amidino group, and a carboxyl group.

Specifically, the buffer material may be represented by the following Chemical Formula 2, and more specifically, may be represented by the following Chemical Formulas 3 to 5. However, it is not necessarily limited thereto.

[Formula 2]

In the formula, each R independently consists of a linear or branched alkyl group having 1 to 10 carbon atoms, a perfluorinated alkyl group, a hydrogen atom, a halogen atom, a hydroxyl group, a nitro group, an amino group, a cyano group, an alkoxy group, an amidino group and a carboxyl group. Selected from the group. In this case, it is preferable that at least one R is a linear or branched alkyl group or a perfluorinated alkyl group having 4 to 10 carbon atoms.

[Formula 3]

[Formula 4]

[Formula 5]

Meanwhile, in the above formulas, specific examples of the alkyl group which is a substituent include methyl, ethyl, propyl, isobutyl, sec-butyl, tert-butyl, pentyl, iso-amyl, hexyl, and the like as the linear or branched alkyl group. One or more hydrogen atoms included in the may be substituted with an alkyl group having 1 to 10 carbon atoms, a halogen atom, a hydroxyl group, a nitro group, an amino group, a cyano group, an alkoxy group, an amidino group, a hydrazine group, or a carboxyl group.

The heteroalkyl group means that at least one carbon atom in the main chain of the alkyl group, preferably 1 to 5 carbon atoms is substituted with a hetero atom such as O, S, N, P and the like.

By aryl group is meant a carbocycle aromatic system comprising at least one aromatic ring, which rings may be attached or fused together in a pendant manner. Specific examples of the aryl group include aromatic groups such as phenyl, naphthyl, tetrahydronaphthyl and the like, and one or more hydrogen atoms in the aryl group may be substituted with the same substituents as in the alkyl group.

The heteroaryl group means a ring aromatic system having 5 to 30 ring atoms containing 1, 2 or 3 hetero atoms selected from N, O, P or S, and the remaining ring atoms are C, and the rings are pendant. It can be attached or fused together. At least one hydrogen atom of the heteroaryl group may be substituted with the same substituent as in the alkyl group.

Said alkoxy group refers to a radical-O-alkyl, wherein alkyl is as defined above. Specific examples include methoxy, ethoxy, propoxy, isobutyloxy, sec-butyloxy, pentyloxy, iso-amyloxy, hexyloxy, and the like. At least one hydrogen atom of the alkoxy group may be selected from the alkyl group. Substituent with the same substituent as the case may be sufficient.

The heteroalkoxy group has essentially the meaning of said alkoxy, except that one or more heteroatoms such as oxygen, sulfur or nitrogen may be present in the alkyl chain, for example CH ₃ CH ₂ OCH ₂ CH ₂ O—, C ₄ H ₉ OCH ₂ CH ₂ OCH ₂ CH ₂ O- and CH ₃ O (CH ₂ CH ₂ O) _n H and the like.

The arylalkyl group means that some of the hydrogen atoms in the aryl group as defined above are substituted with radicals such as lower alkyl, for example methyl, ethyl, propyl and the like. For example benzyl, phenylethyl and the like. At least one hydrogen atom of the arylalkyl group may be substituted with the same substituent as in the alkyl group.

The heteroarylalkyl group means that a part of the hydrogen atoms of the heteroaryl group is substituted with a lower alkyl group, and the definition of heteroaryl in the heteroarylalkyl group is as described above. At least one hydrogen atom of the heteroarylalkyl group may be substituted with the same substituent as in the alkyl group.

Said aryloxy group refers to a radical-O-aryl, wherein aryl is as defined above. Specific examples include phenoxy, naphthoxy, anthracenyloxy, phenanthrenyloxy, fluorenyloxy, indenyloxy, and the like, and at least one hydrogen atom in the aryloxy group may be substituted with the same substituent as in the alkyl group. Do.

Said heteroaryloxy group refers to a radical-O-heteroaryl, wherein heteroaryl is as defined above.

Specific examples of the heteroaryloxy group include benzyloxy, phenylethyloxy group and the like, and at least one hydrogen atom of the heteroaryloxy group may be substituted with the same substituent as in the alkyl group.

The cycloalkyl group refers to a monovalent monocyclic system having 5 to 30 carbon atoms. At least one hydrogen atom of the cycloalkyl group may be substituted with the same substituent as in the alkyl group.

The heterocycloalkyl group refers to a monovalent monocyclic system having 5 to 30 ring atoms containing 1, 2 or 3 heteroatoms selected from N, O, P or S, and the remaining ring atoms are C. At least one hydrogen atom of the cycloalkyl group may be substituted with the same substituent as in the alkyl group.

The alkyl ester group means a functional group to which an alkyl group and an ester group are bonded, wherein the alkyl group is as defined above.

The heteroalkyl ester group means a functional group to which a heteroalkyl group and an ester group are bonded, wherein the heteroalkyl group is as defined above.

The aryl ester group means a functional group having an aryl group and an ester group bonded thereto, wherein the aryl group is as defined above.

The heteroaryl ester group means a functional group having a heteroaryl group and an ester group bonded thereto, wherein the heteroaryl group is as defined above.

The amino group means —NH ₂ , —NH (R) or —N (R ′) (R ″), wherein R ′ and R ″ are each independently an alkyl group having 1 to 10 carbon atoms.

The buffer layer according to the embodiment of the present invention including such a buffer material may be formed into a thin film according to a conventional method known in the art.

Specifically, for example, the buffer material may be dissolved in a suitable organic solvent to form a thin film by a conventional coating or deposition method.

In this case, as the organic solvent, a person skilled in the art can appropriately select and determine a solvent having high solubility according to the structure and type of a specific buffer material. For example, methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n- Alcohols including butyl alcohol, sec-butyl alcohol, t-butyl alcohol, isobutyl alcohol, diacetone alcohol; Ketones including acetone, methyl ethyl ketone and methyl isobutyl ketone; Ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butylene glycol, hexylene glycol, 1,3-propanediol, 1,4-butanediol, 1,2,4-butanetriol, 1,5-pentane Glycols including diol, 1,2-hexanediol, 1,6-hexanediol; Glycol ethers including ethylene glycol monomethyl ether and triethylene glycol monoethyl ether; Glycol ether acetates including propylene glycol monomethyl ether acetate (PGMEA); Acetates including ethyl acetate, butoxyethoxy ethyl acetate butyl carbitol acetate (BCA), dihydroterpineol acetate (DHTA); Terpineols; Trimethyl pentanediol monoisobutyrate (TEXANOL); Dichloroethene (DCE); Chlorobenzene; Xylene; And N-methyl-2-pyrrolidone (NMP) and the like can be used alone or in combination of two or more, but is not limited thereto.

In addition, the buffer layer may be formed by spin coating, dip coating, roll coating, screen coating, spray coating, spin casting, Flow coating, screen printing, ink jet, drop casting, or vacuum deposition may be used, but is not limited thereto.

The addition amount of the buffer material can be determined by those skilled in the art as appropriately selected according to the use and the case, and preferably in an amount of 0.01 to 10 parts by weight based on 100 parts by weight of the solvent. In the thin film formation experiment, if the concentration of the buffer material exceeds 10 wt%, the concentration is too thick to form a uniform thin film.

The buffer layer formed through this process may have a thickness in the range of 0.1 nm to 100 nm, but is not necessarily limited thereto, and those skilled in the art may appropriately adjust it according to the use and the case.

Another embodiment of the invention relates to an electronic device comprising the buffer layer.

Specifically, another embodiment of the present invention provides an electronic device including the buffer layer on the electrode surface.

When the buffer layer according to the embodiment of the present invention is stacked on the electrode surface, the contact resistance between the electrode and the semiconductor layer or the charge transport layer interface can be reduced, so that the injection of electrons or holes as carriers and the charge transfer between the layers are promoted. The effect is that the resulting electronic device exhibits excellent electrical properties.

In an embodiment of the present invention, an electronic device refers to an electronic component using conduction of electrons in a solid, and examples of the electronic device usable in the embodiment of the present invention include OTFT (Organic Thin Film Transistor), OLED ( Organic light emitting diodes, organic light emitting diodes, solar cells, organic photoelectric conversion devices, and the like, but are not necessarily limited thereto.

Specifically, when the buffer layer according to the embodiment of the present invention is applied to the organic thin film transistor, the organic thin film transistor includes a substrate, a gate electrode, a gate insulating film, a source / drain electrode, a buffer layer, and an organic semiconductor layer. In this case, the buffer layer may have a structure formed on the gate electrode or the source / drain electrode.

The organic thin film transistor may have a structure such as a normal bottom contact, a top contact or a top gate, and may have a structure modified within a range that does not impair the purpose.

In addition, in the electronic device according to the embodiment of the present invention, the remaining components other than the buffer layer may be formed through materials and formation methods commonly used in the art.

For example, in the case of an organic thin film transistor, glass, silicon, plastic, or the like may be used as the substrate, and a metal, a conductive polymer, or a metal oxide that is commonly used may be used as the gate electrode or the source / drain electrode. Specifically, gold (Au), silver (Ag), aluminum (Al), nickel (Ni), molybdenum (Mo), tungsten (W), indium tin oxide (ITO), polythiophene, polyaniline (polyaniline) ), Polyacetylene, polypyrole, polyphenylene vinylene, PEDOT (polyethylenedioxythiophene) / PSS (polystyrenesulfonate) mixture, ITO (Indium-tin oxide), IZO (Indium-zinc oxide) For example, but is not limited thereto.

In addition, the gate insulating film may be a conventional organic material such as polyolefin, polyvinyl, polyacrylate, polystyrene, polyurethane, polyimide, polyvinylphenol and derivatives thereof, SiN _x (0 <x <4), SiO ₂ and Al. Inorganic materials such as ₂ O _3, and the like, and the organic semiconductor layer may include pentacene, tetracene, copper phthalocyanine, polythiophene, polyaniline, polyacetylene, polypyrrole, polyphenylenevinylene, derivatives thereof, and the like. May be used, but is not limited thereto.

Meanwhile, when the buffer layer according to the embodiment of the present invention is applied to an organic light emitting diode, the organic light emitting diode has a structure including an anode, a buffer layer, an emission layer (EML), an electron transport layer (ETL), and a cathode on a substrate. Can be. Also, the remaining components except for the buffer layer may be formed using materials and methods commonly used in the art.

Hereinafter, the present invention will be described in detail with reference to Examples, but these Examples are only for illustrating the present invention, and should not be construed as limiting the protection scope of the present invention.

Production Example  One: Flu - SPNB - Flu Synthesis of

1-1: 9,9- BIS (2- ethylhexyl ) -9H- fluorene -2- ylbromoic acid  ( BFB ) Synthesis

To synthesize BFB, 2-bromo-9H-fluorene (5 g, 20.4 mmol) and t-BuOK (5.7 g, 50 mmol) were dissolved in DMF, followed by addition of 2-ethyhexyl bromide (8 ml, 44.9 mmol). After reacting for 12 hours while maintaining 40 ^o C, extraction was performed using ethyl ether and distilled water, and 2-ethyhexyl bromide that was not involved in the reaction was removed by vacuum distillation. Column chromatography was used for purification and the developing solvent was petroleum ether, obtaining 8.5 g (88%) of BF-EH.

Following BE-EH (5g, 10.6mmol) was added slowly to the (2.5M in hexane) n-BuLi 5ml under -78 ^o C was dissolved in THF for 30 minutes while maintaining a -78 ^o C After stirring for 1 hour Triisopropyl borate (2.97 mL, 12.9 mmol) was added. After reacting at room temperature for 12 hours, after completion of the reaction, the mixture was extracted with ethyl ether and distilled water, and purified by column chromatography with developing solvent petroleum ether / ethyl acetate to obtain 3.2 g (69%) of BFB.

1-2: Flu - SPNB - Flu Synthesis of

BFB (0.45 g, 1.03 mmol) and SPNB (0.2 g, 0.42 mmol) were dissolved in 30 mL of toluene, Pd (PPh ₃ ) ₄ (20 mg) and 2.0 M Na ₂ CO ₃ (4.2 mmol) was added and stirred at 90 ° C for 24 h. The obtained reaction mixture was cooled, extracted with petroleum ether, dried over MgSO ₄ , and the solvent was removed. The remaining material was purified by column chromatography using petroleum ether / ethyl acetate 4: 1 as a developing solvent, and 0.3 g of Flu-SPNB-Flu was added. (64%) A white solid was obtained.

Absorbance and PL spectra of the prepared Flu-SPNB-Flu are shown in FIG. 1, and a thermogravimetry analysis graph and a differential scanning calorimetry graph of Flu-SPNB-Flu are shown in FIGS. 2 and 3, respectively. Shown in

Example  One: Flu - SPNB - Flu Buffer layer  Fabrication of Including Diode-Like Devices

As shown in FIG. 4, 1 nm of Flu-SPNB-Flu having the SPN core structure synthesized according to Preparation Example 1 was dissolved in xylene and formed into a patterned ITO glass 1 by spin coating method at 1000 nm at 10 nm thickness. The buffer layer 2 was formed. Then, pentacene was thermally deposited in a 10 ^-6 Torr vacuum to form an organic semiconductor layer 3 having a thickness of 70 nm, and Au (4) was thermally deposited at a thickness of 70 nm to form a diode-like device. Made. The diode-like device is a hole-only device, and the electron injection is very small considering the work function of the electrode.

Comparative example  One

A diode-like device was made in the same manner as in Example 1 except that there was no buffer layer.

The current-voltage characteristics of the diode-like devices of Example 1 and Comparative Example 1 were measured, respectively, and are shown in FIG. 5. In order to confirm the effect of hole injection into the channel layer from ITO, which is likely to be used in bankplane for large area display in the future, connect positive electrode to positive electrode and negative electrode to Au. The change of the current was confirmed while increasing.

Referring to FIG. 5, in the case of Example 1 having a buffer layer including a material having an SPN core, the current increased by 50 times when the voltage was 10V compared to when the buffer layer of Comparative Example 1 was not present. From this, the adhesion of ITO and pentacene was improved through the buffer layer including the material having the SPN core, and the charge injection and transport were improved by matching the energy level of the buffer layer and pentacene. Able to know.

Although the present invention has been described in detail with reference to the preferred embodiments of the present invention as described above, these are merely exemplary, and those skilled in the art to which the present invention pertains various modifications and equivalents therefrom. It will be appreciated that one other embodiment is possible. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

A buffer layer comprising a material having a diaza spirobifluorene core structure according to embodiments of the present invention is a novel structure containing a diaza spirobifluorene (SPN) structure containing a nitrogen atom in its core. In the electronic device including the buffer layer according to the embodiments of the present invention, including the buffer material, the efficiency of the electronic device may be improved by improving carrier injection and transport.

Claims (9)

A buffer layer comprising a material having a diaza spirobifluorene core structure represented by Formula 1 below: [Formula 1]

Where R ₁ and R ₂ are each independently a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted heteroalkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms, substituted or unsubstituted Substituted heteroalkoxy group having 1 to 30 carbon atoms, substituted or unsubstituted aryl group having 6 to 30 carbon atoms, substituted or unsubstituted arylalkyl group having 6 to 30 carbon atoms, substituted or unsubstituted aryloxy group having 6 to 30 carbon atoms , Substituted or unsubstituted heteroaryl group having 2 to 30 carbon atoms, substituted or unsubstituted heteroarylalkyl group having 2 to 30 carbon atoms, substituted or unsubstituted heteroaryloxy group having 2 to 30 carbon atoms, substituted or unsubstituted carbon atoms A cycloalkyl group of 5 to 20, a substituted or unsubstituted heterocycloalkyl group having 2 to 30 carbon atoms, a substituted or unsubstituted alkyl ester group having 1 to 30 carbon atoms, substituted or unsubstituted A is selected from 1 to 30 carbon atoms in the heterocyclic alkyl ester group, a substituted or unsubstituted aryl ester group of a ring having 6 to 30 carbon atoms and a substituted or unsubstituted hetero group, an aryl ester of a ring containing 2 to 30 carbon atoms. According to claim 1, wherein R ₁ and R ₂ are each independently a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 carbon atoms, the aryl group or hetero Rings forming an aryl group are fused with each other. The substituent substituted by the aryl group or heteroaryl group is a linear or branched alkyl group having 1 to 10 carbon atoms, perfluorinated alkyl group, halogen atom, hydroxy group, nitro group, amino group, cyano group, alkoxy group, A buffer layer, characterized in that at least one selected from the group consisting of an amidino group, and a carboxyl group. The buffer layer of claim 1, wherein the material having a diaza spirobifluorene core structure is represented by the following Chemical Formula 2: [Formula 2]

In the formula, each R independently consists of a linear or branched alkyl group having 1 to 10 carbon atoms, a perfluorinated alkyl group, a hydrogen atom, a halogen atom, a hydroxyl group, a nitro group, an amino group, a cyano group, an alkoxy group, an amidino group and a carboxyl group. Selected from the group. The buffer layer of claim 4, wherein the material represented by Chemical Formula 2 is represented by the following Chemical Formulas 3 to 5. [Formula 3]

[Formula 4]

[Formula 5]

The method of claim 1, wherein the buffer layer is spin coating (dip coating), dip coating (dip coating), roll coating (roll coating), screen coating (spray coating), spin casting (spin casting) And a buffer layer formed of a thin film using a flow coating, screen printing, ink jet, drop casting, or vacuum deposition method. The buffer layer of claim 1, wherein the buffer layer has a thickness of 0.1 nm to 100 nm. An electronic device comprising a buffer layer according to claim 1 on an electrode surface. The electronic device of claim 8, wherein the electronic device is selected from an organic thin film transistor (OTFT), an organic light emitting diode (OLED), a solar cell, and an organic photoelectric conversion device.

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