CN103928628A - A modified indium tin oxide anode and its preparation method and organic electroluminescent device - Google Patents

Abstract

The embodiments of the invention disclose a modification indium tin oxide anode. The modification indium tin oxide anode comprises an indium tin oxide anode and a modification layer. The indium tin oxide anode comprises a glass substrate and an indium tin oxide film arranged on the surface of the glass substrate. The modification layer is arranged on the surface of the indium tin oxide film. The modification layer is a fluorine containing dipole layer existing in an In-F form, which is formed through bonding of the indium on the surface of the indium tin oxide film and fluorine. The mass percentage of the fluorine element of the fluorine containing dipole layer is 11%-20%. The ratio of the mass percentage of a tin element to the mass percentage of an indium element is 0.004-0.017. The existence of the fluorine containing dipole layer enables the work content of the surface of the anode to be improved. Besides, the embodiments of the invention further disclose a preparation method of the modification indium tin oxide anode, and an organic electroluminescent device using the modification indium tin oxide anode.

Description

A modified indium tin oxide anode and its preparation method and organic electroluminescent device

technical field

The invention relates to the related field of electronic devices, in particular to a modified indium tin oxide anode, a preparation method thereof and an organic electroluminescent device.

Background technique

At present, in the organic semiconductor industry, organic electroluminescent devices (OLEDs) have the characteristics of high brightness, wide range of material selection, low driving voltage, full-cure active light emission, etc., and have the advantages of high definition, wide viewing angle, and fast response speed. , is a very potential display technology and light source, in line with the development trend of mobile communication and information display in the information age, and the requirements of green lighting technology, it is the focus of many researchers at home and abroad.

In the structure of organic electroluminescent devices, the anode, as an important part of the device structure, undertakes the role of carrier injection and circuit connection, and at the same time, the carrier injection and the interface barrier between the electrode and the organic material related. The anode generally undertakes the role of hole injection. The commonly used conductive oxide film such as indium tin oxide (ITO) has a work function of only 4.7eV, while the organic hole transport material used has a HOMO energy level of 5.1 V, which leads to the need to overcome a large potential barrier for hole injection, resulting in low hole injection efficiency. Improving the work function of ITO will greatly help to improve the hole injection efficiency. At present, the purpose of improving the work function is generally achieved by reducing the Sn/In ratio of ITO surface elements or increasing the content of surface oxygen atoms. In addition, forming a dipole layer on the surface of the anode can also achieve this effect.

Contents of the invention

In order to solve the above-mentioned technical problems, the present invention aims to provide a modified indium tin oxide anode and a preparation method thereof, in which a fluorine-containing dipole layer is formed on the surface of an indium tin oxide film by modifying the surface of the indium tin oxide anode, The surface work function of the anode is improved, so that the anode can greatly improve the hole injection efficiency in application, and improve the luminous efficiency of the device. The present invention also provides an organic electroluminescent device comprising the above-mentioned modified indium tin oxide anode.

In a first aspect, the present invention provides a modified indium tin oxide anode, including an indium tin oxide anode and a modification layer, the indium tin oxide anode includes a glass substrate and an indium tin oxide film disposed on the surface of the glass substrate, the The modification layer is arranged on the surface of the indium tin oxide film, and the modification layer is a fluorine-containing dipole layer in the form of In-F formed by bonding indium and fluorine on the surface of the indium tin oxide film. The mass percent content of fluorine element in the pole layer is 11-20%, and the mass percentage content ratio of tin element and indium element is 0.004-0.017.

Preferably, the thickness of the indium tin oxide thin film is 70-200 nm.

In a second aspect, the present invention provides a method for preparing a modified indium tin oxide anode, comprising the following steps:

The indium tin oxide anode includes a glass substrate and an indium tin oxide film arranged on the surface of the glass substrate;

Immerse the indium tin oxide anode in a fluorine-containing organic acid aqueous solution with a concentration of 0.2-2mol/L, soak at 5-20°C for 0.5-2 minutes, take it out, and dry it;

The dried indium tin oxide anode is placed in the plasma equipment, and the fluorine-containing gas is introduced to make the gas pressure in the plasma equipment 10Pa~60Pa, adjust the radio frequency power to 40w~100w, and perform plasma treatment for 5~ In 10 minutes, a modified indium tin oxide anode was obtained. The surface of the modified indium tin oxide anode has a modified layer, and the modified layer is formed by bonding indium and fluorine on the surface of the indium tin oxide film and exists in the form of In-F. Fluorine-containing dipole layer.

The percentage content of fluorine element in the fluorine-containing dipole layer is 11-20%, and the mass percentage content ratio of tin element and indium element is 0.004-0.017.

The indium tin oxide anode includes a glass substrate and an indium tin oxide thin film arranged on the surface of the glass substrate. The preparation method is as follows: a clean glass substrate is provided, and a magnetron sputtering method is used to sputter on the glass substrate to prepare an indium tin oxide thin film.

The glass substrate is commercially available common glass.

Preferably, the cleaning operation of the glass substrate is as follows: sequentially use detergent, deionized water, isopropanol and acetone to perform ultrasonic cleaning for 20 minutes respectively, and then blow dry with nitrogen.

Preferably, the thickness of the indium tin oxide thin film is 70-200 nm.

The indium tin oxide anode is immersed in an aqueous solution of fluorine-containing organic acid with a concentration of 0.2-2 mol/L, soaked at 5-20° C. for 0.5-2 minutes, taken out, and dried.

Preferably, the fluorine-containing organic acid is difluoroacetic acid, trifluoroacetic acid or 2,2-difluoropropionic acid.

Preferably, the concentration of the fluorine-containing organic acid aqueous solution is 0.5-1 mol/L.

The specific method of drying is not particularly limited. Preferably, the drying operation is: vacuum drying at 50-80° C. for 12-24 hours.

After the indium tin oxide anode is pretreated with a fluorine-containing organic acid, a large number of fluorine-containing functional groups are adsorbed on its surface. Since fluorine has a strong electron-withdrawing ability, these fluorine-containing functional groups will The surface and indium In form part of the In-F bond, so that part of the Sn on the surface of indium tin oxide (ITO) is replaced by F, but the In-F bond formed at this time is not very stable and needs further processing.

The dried indium tin oxide anode is placed in a plasma device, and a fluorine-containing gas is passed through for plasma treatment to obtain a modified indium tin oxide anode. The surface of the modified indium tin oxide anode has a modified layer, and the modified layer is a fluorine-containing dipole layer in the form of In-F formed by bonding of In and F on the surface of the indium tin oxide film.

Preferably, the fluorine-containing gas is carbon tetrafluoride or carbon trifluoride.

During the plasma treatment process, the gas pressure in the plasma equipment is 10~60Pa, the radio frequency power is 40~100w, and the plasma treatment time is 5~10 minutes.

After the indium tin oxide anode is treated with fluorine-containing gas plasma, the unstable In-F bond will become more stable; at the same time, the fluorine in the fluorine-containing gas will also form In-F bond with indium (In) on the surface of ITO , so that the tin (Sn) on the surface of ITO is further replaced by fluorine (F); in addition, the fluorine-containing functional groups that are not bonded to ITO and adsorbed on the surface after pretreatment with fluorine-containing organic acids will also form In-F with In bond, thereby further increasing the ratio of In-F bonds on the ITO surface, increasing the percentage of element F on the anode surface, and reducing the Sn/In element content ratio on the anode surface. In this way, a layer of fluorine-containing dipole layer in the form of In-F will be formed on the surface of the anode ITO. The percentage of fluorine in the fluorine-containing dipole layer is 11-20%. The mass percentage ratio of 0.004~0.017, therefore, compared with the ordinary unmodified ITO anode, the presence of the fluorine-containing dipole layer as a modified layer can improve the surface work function of the ITO anode, thereby reducing the barrier that needs to be overcome for hole injection , to improve the hole injection efficiency. This is because the existence of the dipole layer will increase the vacuum energy level E _vac on the surface of ITO, and increase a value δ, so that the difference ΔE between the Fermi energy level _EF of the anode and the vacuum energy level E _vac is compared with the original difference The value is more than δ. According to the definition of the work function, the work function is the difference between the Fermi level and the vacuum energy level of the material, which means that the work function increases the δ value. That is, the presence of the fluorine-containing dipole layer increases the work function of the anode surface.

The modified indium tin oxide anode should be properly stored in a vacuum environment <10 ⁻³ Pa or in a N ₂ glove box.

In a third aspect, the present invention provides an organic electroluminescent device, including an anode, a functional layer, a light-emitting layer and a cathode, the anode is a modified indium tin oxide anode, and the modified indium tin oxide anode includes an indium tin oxide anode and A modification layer, the indium tin oxide anode includes a glass substrate and an indium tin oxide thin film disposed on the surface of the glass substrate, the modification layer is disposed on the surface of the indium tin oxide thin film, and the modification layer is the indium tin oxide A fluorine-containing dipole layer in the form of In-F formed by indium and fluorine on the surface of the film. The mass percentage ratio is 0.004~0.017.

Preferably, the thickness of the indium tin oxide thin film is 70-200 nm.

Wherein, the functional layer includes at least one of a hole injection layer, a hole transport layer, an electron transport layer and an electron injection layer.

When the functional layer is multi-layered, the hole injection layer, hole transport layer, light emitting layer, electron transport layer, electron injection layer and cathode are sequentially arranged on the surface of the ITO thin film of the modified indium tin oxide anode.

The material of the hole injection layer can be zinc phthalocyanine (ZnPc), copper phthalocyanine (CuPc), vanadyl phthalocyanine (VOPc), titanium phthalocyanine (TiOPc), platinum phthalocyanine (PtPc) or 4,4 ',4″-tris(N-3-methylphenyl-N-phenylamino)triphenylamine (m-MTDATA). The thickness of the hole injection layer is 10~40nm.

The hole transport material of the hole transport layer can be N,N'-diphenyl-N,N'-bis(3-methylphenyl)-1,1'-biphenyl-4,4'- Diamine (TPD); N,N,N',N'-tetramethoxyphenyl)-p-diaminobiphenyl (MeO-TPD); 2,7-bis(N,N-di(4-methyl oxyphenyl)amino)-9,9-spirobifluorene (MeO-Sprio-TPD), N,N'-diphenyl-N,N'-di(1-naphthyl)-1,1'- Biphenyl-4,4'-diamine (NPB), 1,1-bis(4-(N,N'-bis(p-tolyl)amino)phenyl)cyclohexane (TAPC) or 2,2 ', 7,7'-tetra(N,N-diphenylamino)-9,9'-spirobifluorene (S-TAD), the thickness of the hole transport layer is 20~50nm.

The material of the light-emitting layer is a mixed material formed by doping a light-emitting material with a hole-transport material or an electron-transport material.

The luminescent material can be 4-(dinitrile methyl)-2-butyl-6-(1,1,7,7-tetramethyljulonesidine-9-vinyl)-4H-pyran ( DCJTB), 2,3,6,7-tetrahydro-1,1,7,7-tetramethyl-1H,5H,11H-10-(2-benzothiazolyl)-quinazino[9,9A ,1GH]coumarin (C545T), bis(2-methyl-8-hydroxyquinoline)-(4-biphenol)aluminum (BALQ), 4-(dinitrilemethylenyl)-2-isopropyl -6-(1,1,7,7-Tetramethyljuronesidine-9-vinyl)-4H-pyran (DCJTI), Dimethylquinacridone (DMQA), 8-Hydroxyquinoline Aluminum (Alq3), 5,6,11,12-Tetraphenylnaphthalene (Rubrene), 4,4'-bis(2,2-distyryl)-1,1'-biphenyl (DPVBi) , bis(4,6-difluorophenylpyridine-N,C2)iridium picolinate (FIrpic), bis(4,6-difluorophenylpyridine)-tetrakis(1-pyrazolyl)iridium borate (FIr6), bis(4,6-difluoro-5-cyanophenylpyridine-N,C2)iridium picolinate (FCNIrpic), bis(2′,4′-difluorophenyl)pyridine](tetra pyridine) iridium (FIrN4), bis(2-methyl-diphenyl[f,h]quinoxaline) (acetylacetonate) iridium (Ir(MDQ)2(acac)), bis(1-phenyl Isoquinoline) (acetylacetonate) iridium (Ir(piq)2(acac)), bis(2-phenylpyridine)iridium acetylacetonate (Ir(ppy)2(acac)), tris(1-phenyl One or more of the base-isoquinoline) iridium (Ir(piq)3) or tris(2-phenylpyridine)iridium (Ir(ppy)3). The thickness of the light emitting layer is 10~20nm.

The electron transport material of the electron transport layer can be 2-(4-biphenyl)-5-(4-tert-butyl)phenyl-1,3,4-oxadiazole (PBD), (8-hydroxy Quinoline)-aluminum (Alq3), 4,7-diphenyl-o-phenanthroline (Bphen), 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene ( TPBi), 2,9-dimethyl-4,7-biphenyl-1,10-phenanthroline (BCP), 1,2,4-triazole derivatives (such as TAZ) or bis(2- Methyl-8-hydroxyquinoline-N ₁ ,O ₈ )-(1,1′-biphenyl-4-hydroxy)aluminum (BAlq). The thickness of the electron transport layer is 30~60nm.

The material of the electron injection layer can be LiF, CsF or NaF, and the thickness is 1nm;

The cathode can be Ag, Al, Sm, Yb, Mg-Ag alloy or Mg-Al alloy, with a thickness of 70-200nm.

The above-mentioned hole injection layer, hole transport layer, light emitting layer, electron transport layer, electron injection layer and cathode can be sequentially prepared on the modified indium tin oxide anode by vacuum evaporation.

Implementing the embodiment of the present invention has the following beneficial effects:

(1) The preparation method of the modified indium tin oxide anode provided by the present invention reduces the Sn/In element content ratio on the surface of the anode by subjecting the indium tin oxide anode to pretreatment with fluorine-containing organic acid and plasma treatment with fluorine-containing gas, and at the same time A modified layer is formed on the surface of the indium tin oxide anode, that is, a fluorine-containing dipole layer in the form of In-F, thereby improving the work function of the anode surface;

(2) The preparation method of the modified indium tin oxide anode provided by the present invention has simple process and low cost;

(3) The modified indium tin oxide anode provided by the present invention can be widely used in organic electroluminescent devices and organic solar cells to improve the efficiency of the devices.

Description of drawings

Figure 1 is a structural diagram of an organic electroluminescent device provided in Example 1 of the present invention;

Fig. 2 is a graph showing the relationship between current density and voltage of the organic electroluminescent device provided by Example 4 of the present invention and the existing organic electroluminescent device.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

Example 1

A method for preparing a modified indium tin oxide anode, comprising the following steps:

(1) Take the glass substrate, ultrasonically clean it with detergent, deionized water, isopropanol and acetone for 20 minutes, and then dry it with nitrogen; prepare indium oxide with a thickness of 100nm on the glass substrate by magnetron sputtering Tin film, obtain indium tin oxide anode;

(2) Immerse the indium tin oxide anode in an aqueous difluoroacetic acid solution with a concentration of 2 mol/L, soak it at 10°C for 0.5 minutes, take it out, and dry it under vacuum at 50°C for 12 hours;

(3) Place the dried indium tin oxide anode in the plasma equipment, pass through carbon tetrafluoride (CF4) gas for plasma treatment, and obtain a modified indium tin oxide anode, and the surface of the modified indium tin oxide anode has a modified layer , the modification layer is a fluorine-containing dipole layer in the form of In-F formed by the bond between In and F on the surface of the indium tin oxide film.

During the plasma treatment process, the gas pressure in the plasma equipment is 10Pa, the radio frequency power is 50w, and the plasma treatment time is 6 minutes.

The modified indium tin oxide anode prepared in this example has a surface modification layer that is a fluorine-containing dipole layer in the form of In-F. This dipole layer will increase the vacuum energy level E _vac of the ITO surface and increase a value δ , so that the difference ΔE between the Fermi level _EF of the anode and the vacuum level E _vac is δ more than the original difference. According to the definition of the work function, the work function is the difference between the Fermi level of the material and the vacuum energy level, which means that the work function increases the δ value. The surface work function of the unmodified indium tin oxide anode is generally 4.7eV, and the surface work function of the modified indium tin oxide anode prepared in this embodiment is 5.7eV.

Example 2

A method for preparing a modified indium tin oxide anode, comprising the following steps:

(1) Take the glass substrate, ultrasonically clean it with detergent, deionized water, isopropanol and acetone for 20 minutes, and then dry it with nitrogen; prepare indium oxide with a thickness of 70nm on the glass substrate by magnetron sputtering Tin film, obtain indium tin oxide anode;

(2) Immerse the indium tin oxide anode in an aqueous solution of trifluoroacetic acid with a concentration of 0.2mol/L, soak at 20°C for 2 minutes, take it out, and dry it under vacuum at 80°C for 12 hours;

(3) Place the dried indium tin oxide anode in the plasma equipment, pass through carbon trifluoride (CHF3) gas for plasma treatment, and obtain a modified indium tin oxide anode, and the surface of the modified indium tin oxide anode has a modified layer , the modification layer is a fluorine-containing dipole layer in the form of In-F formed by the bond between In and F on the surface of the indium tin oxide film.

During the plasma treatment process, the gas pressure in the plasma equipment is 30Pa, the radio frequency power is 40w, and the plasma treatment time is 10 minutes.

The surface work function of the modified indium tin oxide anode prepared in this example is 5.8 eV.

Example 3

A method for preparing a modified indium tin oxide anode, comprising the following steps:

(1) Take the glass substrate, ultrasonically clean it with detergent, deionized water, isopropanol and acetone for 20 minutes, and then dry it with nitrogen; prepare indium oxide with a thickness of 200nm on the glass substrate by magnetron sputtering Tin film, obtain indium tin oxide anode;

(2) Immerse the indium tin oxide anode in 2,2-difluoropropionic acid aqueous solution with a concentration of 1mol/L, soak at 5°C for 1 minute, take it out, and dry it in vacuum at 60°C for 24 hours;

(3) The dried indium tin oxide anode is placed in a plasma device, and carbon tetrafluoride (CF ₄ ) gas is introduced for plasma treatment to obtain a modified indium tin oxide anode. The surface of the modified indium tin oxide anode has a modified The modification layer is a fluorine-containing dipole layer in the form of In-F formed by the bond between In and F on the surface of the indium tin oxide film.

During the plasma treatment process, the gas pressure in the plasma treatment chamber is 60Pa, the radio frequency power is 100w, and the plasma treatment time is 5 minutes.

The surface work function of the modified indium tin oxide anode prepared in this example is 5.9 eV.

The modified indium tin oxide anode obtained in the above-mentioned examples 1 to 3 of the present invention and the unmodified common indium tin oxide anode were subjected to surface element analysis. The test method used XPS (X-ray photoelectron spectroscopy), and the instrument model was ESCA2000 (VG Microtech Inc. company), the test condition is to use the Al target Kα ray source, and the ray energy is 1486.6eV. Calculate the 1s orbit of the C element on the surface of the ITO film, the 3d _5/2 orbit of the In element, the 3d _5/2 orbit of the Sn element, the 1s orbit of the O element, and the 1s orbit of the F element, and calculate the percentage content of each element. The results are shown in Table 1.

Table 1

As can be seen from Table 1, the surface of the unmodified common indium tin oxide anode is composed of C, O, In, and Sn four elements, and the modified indium tin oxide anode after the method of the present invention has more F element, indicating that after modification, F element and In form a bond to form on the surface of the ITO film, thereby forming a fluorine-containing dipole layer in the form of In-F on the surface of the ITO film. It can be seen from the elemental analysis data results that the modified indium tin oxide anode prepared by the present invention has a percentage content of F element in the fluorine-containing dipole layer on the surface of more than 11%, and the highest reaches 19.46%. At the same time, through the modification treatment of the present invention, the Sn/In ratio on the ITO surface is greatly reduced, from 0.188 to 0.004. It shows that F replaces some of the bonds of Sn and forms a bond with In.

Example 4

An organic electroluminescent device, comprising an anode, a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer and a cathode stacked in sequence, the anode is the modified oxide prepared in Example 1 of the present invention Indium tin anode.

Specifically, in this embodiment, the material of the hole injection layer is zinc phthalocyanine (ZnPc) with a thickness of 15 nm; the material of the hole transport layer is N,N'-diphenyl-N,N'-bis(3 -methylphenyl)-1,1'-biphenyl-4,4'-diamine (TPD), with a thickness of 50nm; the material of the light-emitting layer is tris(2-phenylpyridine)iridium (Ir(ppy) ₃ ) A mixed material formed by doping 8% mass fraction of 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene (TPBi), expressed as Ir(ppy) ₃ :TPBi (8%), with a thickness of 15nm; the electron transport material of the electron transport layer is 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene (TPBi), with a thickness of 50nm; The injection layer is made of LiF with a thickness of 1 nm; the cathode is Ag with a thickness of 100 nm.

The structure of the organic electroluminescence device of this embodiment is: ITO anode/modification layer/ZnPc (15nm)/TPD (50nm)/Ir (ppy) ₃ : TPBi (8%, 15nm)/TPBi (50nm)/LiF (1nm )/Ag(100nm).

FIG. 1 is a schematic structural view of the organic electroluminescence device of this embodiment. As shown in FIG. 1 , the structure of the organic electroluminescent device includes a modified ITO anode 10 , a hole injection layer 20 , a hole transport layer 30 , a light emitting layer 40 , an electron transport layer 50 , an electron injection layer 60 and a cathode 70 . Wherein, the modified ITO anode 10 includes an ITO anode 101 and a modified layer 102, and the modified layer 102 is a fluorine-containing dipole layer in the form of In-F.

Compared with the existing organic electroluminescent device, the organic electroluminescent device of the embodiment of the present invention adopts the modified indium tin oxide anode, the work function of the anode surface is improved, and the hole injection efficiency is improved, so that the starting voltage of the device is significantly improved. reduce. The structure of the existing organic electroluminescent device is: common unmodified ITO anode/ZnPc(15nm)/TPD(50nm)/Ir(ppy) ₃ : TPBi(8%, 15nm)/TPBi(50nm)/LiF(1nm) /Ag(100nm). The starting voltage of the existing organic electroluminescent device is 3.0eV, and the starting voltage of the organic electroluminescent device in this embodiment is 2.1eV.

Fig. 2 is a graph showing the relationship between the current density and the voltage of the organic electroluminescent device of this embodiment and the existing light emitting device. Wherein, Curve 1 is a relationship diagram between current density and voltage of the organic electroluminescent device in this embodiment; Curve 2 is a relationship diagram between current density and voltage of an existing organic electroluminescent device. It can be seen from the figure that under the same start-up voltage, the organic electroluminescent device of this embodiment can obtain higher injection current, so that the device has higher luminous efficiency. The luminous efficiency of the existing organic electroluminescent device is 13.1lm/W, and the luminous efficiency of the organic electroluminescent device in this embodiment is 26.4lm/W. This is because the organic electroluminescent device of this embodiment uses a modified indium tin oxide anode, which improves the hole injection efficiency, so that higher carrier injection efficiency can be obtained, and the organic electroluminescence efficiency of the device can be improved.

Example 5

An organic electroluminescent device, comprising an anode, a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer and a cathode stacked in sequence, the anode is the modified oxide prepared in Example 2 of the present invention Indium tin anode. The materials of the hole injection layer, the hole transport layer, the light emitting layer, the electron transport layer, the electron injection layer and the cathode are the same as those in Example 4.

The start-up voltage of the organic electroluminescent device in this embodiment is 2.1 eV, and the luminous efficiency is 31.1 lm/w.

Example 6

An organic electroluminescent device, comprising an anode, a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, an electron injection layer and a cathode stacked in sequence, the anode is the modified oxide prepared in Example 3 of the present invention Indium tin anode. The materials of the hole injection layer, the hole transport layer, the light emitting layer, the electron transport layer, the electron injection layer and the cathode are the same as those in Example 4.

The start-up voltage of the organic electroluminescent device in this embodiment is 2.0 eV, and the luminous efficiency is 35.2 lm/w.

The above description is a preferred embodiment of the present invention, and it should be pointed out that for those skilled in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications are also considered Be the protection scope of the present invention.

Claims (9)

1. A modified indium tin oxide anode, comprising an indium tin oxide anode and a modification layer, the indium tin oxide anode comprising a glass substrate and an indium tin oxide film arranged on the surface of the glass substrate, the modification layer being arranged on the The surface of the indium tin oxide film is characterized in that the modification layer is a fluorine-containing dipole layer in the form of In-F formed by bonding indium and fluorine on the surface of the indium tin oxide film, and the fluorine-containing dipole layer The mass percentage content of the fluorine element is 11-20%, and the mass percentage content ratio of the tin element and the indium element is 0.004-0.017. 2. The modified indium tin oxide anode according to claim 1, wherein the thickness of the indium tin oxide thin film is 70-200 nm. 3. A method for preparing a modified indium tin oxide anode, comprising the following steps: A clean indium tin oxide anode is provided; the indium tin oxide anode includes a glass substrate and an indium tin oxide film arranged on the surface of the glass substrate; Immerse the indium tin oxide anode in a fluorine-containing organic acid aqueous solution with a concentration of 0.2-2mol/L, soak at 5-20°C for 0.5-2 minutes, take it out, and dry it; The dried indium tin oxide anode is placed in the plasma equipment, and the fluorine-containing gas is introduced to make the gas pressure in the plasma equipment 10Pa~60Pa, adjust the radio frequency power to 40w~100w, and perform plasma treatment for 5~ In 10 minutes, a modified indium tin oxide anode was obtained. The surface of the modified indium tin oxide anode has a modified layer, and the modified layer is formed by bonding indium and fluorine on the surface of the indium tin oxide film and exists in the form of In-F. Fluorine-containing dipole layer. 4. The preparation method of modified indium tin oxide anode according to claim 3, characterized in that, the percentage of fluorine element in the fluorine-containing dipole layer is 11-20%, and the mass of tin element and indium element is 100%. The content ratio is 0.004~0.017. 5 . The method for preparing the modified indium tin oxide anode according to claim 3 , wherein the fluorine-containing organic acid is difluoroacetic acid, trifluoroacetic acid or 2,2-difluoropropionic acid. 6 . The method for preparing a modified indium tin oxide anode according to claim 3 , wherein the fluorine-containing gas is carbon tetrafluoride or carbon trifluoride. 7. The method for preparing a modified indium tin oxide anode according to claim 3, wherein the thickness of the indium tin oxide thin film is 70-200 nm. 8. An organic electroluminescent device, comprising an anode, a functional layer, a light-emitting layer and a cathode, characterized in that the anode is a modified indium tin oxide anode, and the modified indium tin oxide anode includes an indium tin oxide anode and a modification layer , the indium tin oxide anode includes a glass substrate and an indium tin oxide film disposed on the surface of the glass substrate, the modification layer is disposed on the surface of the indium tin oxide film, and the modification layer is the surface of the indium tin oxide film A fluorine-containing dipole layer in the form of In-F formed by bonding indium and fluorine, the fluorine element in the fluorine-containing dipole layer is 11 to 20% by mass, and the mass percentage of tin and indium elements is 100%. The content ratio is 0.004~0.017. 9. The organic electroluminescence device according to claim 8, wherein the thickness of the indium tin oxide thin film is 70-200 nm.