KR20220065151A - Coating Material for Manufacturing Conductive film with Work Function Control Based on Metal Oxide - Google Patents

Abstract

The present invention relates to a coating agent capable of preparing a conductive thin film capable of controlling a work function based on the selection of metals to be contained. The coating agent can be coated on an electrode layer of a solar cell or light emitting device in a single process of UV curing and can simply control the work function by changing a component content such as metal oxide powder.

Description

A coating agent capable of manufacturing a conductive thin film capable of controlling a work function based on selection of a metal contained therein {Coating Material for Manufacturing Conductive film with Work Function Control Based on Metal Oxide}

The present invention can be coated on the electrode layer of a solar cell or light emitting device in a single process of UV curing method, and the work function can be controlled simply by changing the content of components such as metal oxide powder. It relates to a coating agent capable of producing a possible conductive thin film.

In order to obtain high efficiency in various devices, including organic electronic devices such as organic thin film transistors and organic solar cells, and graphene-based electronic devices, charge injection and charge transfer must be performed smoothly.

It is the injection energy barrier between the electrode and the active layer that has the greatest effect on the charge injection, and it varies depending on the work function of the electrode or the LUMO or HOMO of the active layer. Therefore, in order to manufacture a high-efficiency device, various techniques have been proposed to change the work function of the electrode by adding a specific material to the electrode, or to reduce the energy barrier by inducing doping in the semiconductor material to activate charge injection. It still occupies a large proportion in device development.

The technology of changing the work function of the double electrode is a technology that uses the principle of coating a very thin insulating material on the electrode to enable electron tunneling to induce an interface dipole with the electrode, and to adjust the work function by changing the electron energy potential.

The technology for controlling the work function is generally a spin coating method suggested in Korean Patent Application Laid-Open No. 10-2012-0121065 (Prior Document 1) and Korean Patent Application Laid-Open No. 10-2013-0006050 (Prior Document 2) or Korean Patent Registration No. 10- There is a method of forming a self-assembled monolayer (Prior Document 4) suggested in No. 0945729 (Prior Document 3) or 10-0977152. However, since the spin coating method or the self-assembly single film formation method uses a solution as a liquid phase process, it is greatly affected by the surface energy of the electrode surface to induce work function control, and requires a separate surface pretreatment such as oxygen plasma treatment, and self-assembly. In the case of the single film formation method, there is a problem that it can be applied only within a limited range because it is made through a specific chemical bond.

As a method for solving this problem, Korean Patent Application Laid-Open No. 10-2015-0047840 (Prior Document 5) proposes a method of forming a work function control film on the surface of a transparent electrode by an atomic layer deposition method. However, since the atomic layer deposition method can be applied only to transparent electrodes, there is a problem in that the work functions of various electrodes cannot be adjusted.

On the other hand, Korean Patent No. 10-1718879 (Prior Document 6) discloses that when a functional polymer thin film of a monomer containing an electron donor group and/or a monomer containing an electron acceptor group is deposited on an electrode using the iCVD process, the work function is controlled. electrode is disclosed.

However, the above prior documents 1 to 6 require complicated processing such as spin coating method, self-assembled single film formation method, iCVD, etc. pretreatment, and there is a problem that the work function cannot be precisely controlled in various ranges.

(Patent Document 0001) Patent Document 1: Korean Patent Publication No. 10-2012-0121065

(Patent Document 0002) Patent Document 2: Korean Patent Publication No. 10-2013-0006050

(Patent Document 0003) Patent Document 3: Korean Patent No. 10-0945729

(Patent Document 0004) Patent Document 4: Korean Patent No. 10-0977152

(Patent Document 0005) Patent Document 5: Korean Patent No. 10-0977152

(Patent Document 0006) Patent Document 6: Korean Patent No. 10-1718879

An object of the present invention is that the electrode layer of a solar cell or a light emitting device can be coated in a single process of an ultraviolet curing method, and the work function can be easily controlled by changing the content of components such as metal oxide powder. To provide a coating agent capable of producing a conductive thin film capable of controlling the function.

In order to solve the above problems, the present invention provides a coating agent that is coated on an electrode layer of a solar cell or a light emitting device to form a conductive thin film capable of controlling a work function on the electrode layer by UV curing, comprising: a UV curable binder; organic solvents; first dispersing aid; a second dispersing aid; metal oxide powder; and a solid powder of poly(3,4-ethylenedioxythiophene)-polystyrenesulfonic acid (PEDOT:PSS), wherein the work function is controlled by controlling the components of the ultraviolet curable binder and the metal oxide powder, and the oxidation The metal powder provides a coating agent comprising at least one of TiO ₂ , WO ₃ , ATO, CuO, MgO, Fe ₃ O ₄ , Fe ₂ O ₃ , CoFe ₂ O ₄ , NiFe ₂ O ₄ , and ZnFe ₂ O ₄ . do.

In one embodiment of the present invention, the coating agent can form a conductive thin film that controls the work function in the range of 4.5 to 4.8 eV on the electrode layer, and the electrode layer includes at least one of an Ag reflective electrode and an Al reflective electrode, , The coating agent may include a metal oxide powder including at least one of TiO ₂ , ATO, MgO, Fe ₃ O ₄ , NiFe ₂ O ₄ , and ZnFe ₂ O ₄ .

In one embodiment of the present invention, the coating agent can form a conductive thin film that controls the work function in the range of 4.9 to 5.2 eV on the electrode layer, and the electrode layer is one of an ITO transparent electrode, an Ag reflective electrode, and an Al reflective electrode or more, wherein the coating agent comprises at least one of TiO ₂ , WO ₃ , ATO, CuO, MgO, Fe ₃ O ₄ , Fe ₂ O ₃ , CoFe ₂ O ₄ , NiFe ₂ O ₄ , and ZnFe ₂ O ₄ . It may include a metal oxide powder.

In one embodiment of the present invention, the coating agent can form a conductive thin film that controls the work function in the range of 5.3 to 5.6 eV on the electrode layer, and the electrode layer includes at least one of an ITO transparent electrode and an Ag reflective electrode, , The coating agent may include a metal oxide powder including at least one of ATO, CuO, MgO, Fe ₃ O ₄ , Fe ₂ O ₃ , CoFe ₂ O ₄ , NiFe ₂ O ₄ , and ZnFe ₂ O ₄ .

In one embodiment of the present invention, the coating agent may form a conductive thin film controlled in the range of 5.7 to 5.9 eV on the electrode layer, and the electrode layer includes at least one of an Ag reflective electrode and an Al reflective electrode, and the coating agent ATO, and CoFe ₂ O ₄ may include a metal oxide powder containing at least one.

In one embodiment of the present invention, when the coating agent is cured on the electrode layer, the conductive thin film is formed on the poly(3,4-ethylenedioxythiophene)-polystyrenesulfonic acid (PEDOT) on the matrix made of the ultraviolet curable binder material. : PSS) may have a structure in which the particles of the solid powder and the particles of the metal oxide powder are connected to each other and dispersed.

In one embodiment of the present invention, the metal oxide powder may account for 0.05 to 2% by weight based on the total weight of the coating agent.

In one embodiment of the present invention, the coating agent, 0.5 to 5% by weight of an ultraviolet curable binder; 85 to 95% by weight of an organic solvent; 2 to 6% by weight of the first dispersing aid; 0.5 to 1.5% by weight of the second dispersing aid; 0.05 to 2% by weight of metal oxide powder; and 0.05 to 2% by weight of poly(3,4-ethylenedioxythiophene)-polystyrenesulfonic acid (PEDOT/PSS) solid powder.

In one embodiment of the present invention, the coating agent is a state in which the solid powder of the poly(3,4-ethylenedioxythiophene)-polystyrenesulfonic acid (PEDOT:PSS) and the metal oxide powder are primarily contained in an organic solvent Dispersion and mixing by shear force by a shear mixer including two or more rotors and a stator in Additional dispersion by a bead mill may be performed in a state in which the solid powder and the metal oxide powder are included.

In order to solve the above problems, the present invention is a method for manufacturing a coating agent that is coated on an electrode layer of a solar cell or a light emitting device and can form a conductive thin film capable of controlling a work function on the electrode layer by UV curing, preparing a first mixture by mixing a binder, an organic solvent, a first dispersing aid, and a second dispersing aid; preparing a second mixture by mixing a solid powder of poly(3,4-ethylenedioxythiophene)-polystyrenesulfonic acid (PEDOT:PSS) with the first mixture; preparing a third mixture by mixing the metal oxide powder with the second mixture; pulverizing the third mixture with a shear mixer to perform stirring; and milling the third mixture with a bead mill to perform agitation, wherein the work function is controlled by adjusting the components of the ultraviolet curable binder and the metal oxide powder, and the metal oxide powder is TiO ₂ , WO ₃ , ATO, CuO, MgO, Fe ₃ O ₄ , Fe ₂ O ₃ , CoFe ₂ O ₄ , NiFe ₂ O ₄ , and ZnFe ₂ O ₄ Containing at least one of, producing a coating agent capable of forming a conductive thin film provide a way

The coating agent capable of manufacturing a conductive thin film capable of controlling a work function based on the selection of a metal containing according to an embodiment of the present invention selectively includes an ultraviolet curable binder and components of a metal oxide powder, thereby an electrode layer including an opaque electrode and a transparent electrode It is possible to exhibit the effect of forming a conductive thin film capable of controlling the work function thereon.

The coating agent capable of forming a conductive thin film capable of controlling the work function based on the selection of the containing metal according to an embodiment of the present invention can exert the effect of controlling the work function by adjusting the components of the ultraviolet curable binder and the metal oxide powder. there is.

The coating agent capable of forming a conductive thin film capable of controlling the work function based on the selection of the containing metal according to an embodiment of the present invention can exert the effect of controlling the work function by adjusting the content of the solid powder of PEDOT:PSS. .

The coating agent capable of manufacturing a conductive thin film capable of controlling a work function based on the selection of a metal containing according to an embodiment of the present invention can easily form a conductive thin film on the electrode layer in a single UV curing process.

The coating agent capable of manufacturing a conductive thin film capable of controlling a work function based on the selection of a metal-containing material according to an embodiment of the present invention can exhibit the effect of stably manufacturing a conductive thin film having a desired work function.

A coating agent capable of manufacturing a conductive thin film capable of controlling a work function based on the selection of a metal containing according to an embodiment of the present invention has a stable structure in which the solid powder of PEDOT:PSS and the metal oxide powder are disposed on an ultraviolet curable binder matrix. and can exhibit the effect of having a homogeneous work function.

1 schematically shows a manufacturing step of a coating agent according to an embodiment of the present invention.
Figure 2 schematically shows the state of the coating agent according to an embodiment of the present invention.
3 schematically shows the particle structure of a conductive thin film according to an embodiment of the present invention.
4 is a graph showing a surface work function of an electrode layer on which a conductive thin film is formed according to an embodiment of the present invention.
5 is a graph illustrating a surface work function of an electrode layer on which a conductive thin film is formed according to an embodiment of the present invention.

Various embodiments and/or aspects are now disclosed with reference to the drawings. In the following description, for purposes of explanation, numerous specific details are set forth to provide a thorough understanding of one or more aspects. However, it will also be recognized by one of ordinary skill in the art that such aspect(s) may be practiced without these specific details. The following description and accompanying drawings set forth in detail certain illustrative aspects of one or more aspects. These aspects are illustrative, however, and some of various methods may be employed in the principles of the various aspects, and the descriptions set forth are intended to include all such aspects and their equivalents.

As used herein, “embodiment”, “example”, “aspect”, “exemplary”, etc. may not be construed as an advantage or advantage in any aspect or design being described over other aspects or designs. .

In addition, the term “or” is intended to mean an inclusive “or” rather than an exclusive “or.” That is, unless otherwise specified or clear from context, "X employs A or B" is intended to mean one of the natural implicit substitutions. That is, X employs A; X employs B; Or, when X employs both A and B, "X employs A or B" can be applied to either of these cases. It should also be understood that the term “and/or” as used herein refers to and includes all possible combinations of one or more of the listed related items.

Also, the terms "comprises" and/or "comprising" mean that the feature and/or element is present, but excludes the presence or addition of one or more other features, elements, and/or groups thereof. should be understood as not

In addition, it will be understood that singular expressions such as "above" and "above" include plural expressions in this specification, unless otherwise clearly indicated. Thus, as an example, a “component surface” includes one or more component surfaces.

Also, terms including an ordinal number, such as first, second, etc., may be used to describe various elements, but the elements are not limited by the terms. The above terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component. and/or includes a combination of a plurality of related listed items or any of a plurality of related listed items.

In addition, the terms used herein are used only to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present specification, terms such as “comprise” or “have” are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, but one or more other features It should be understood that this does not preclude the existence or addition of numbers, steps, operations, components, parts, or combinations thereof.

In addition, in the embodiments of the present invention, unless otherwise defined, all terms used herein, including technical or scientific terms, are generally understood by those of ordinary skill in the art to which the present invention belongs. have the same meaning as Terms such as those defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related art, and unless explicitly defined in an embodiment of the present invention, an ideal or excessively formal meaning is not interpreted as

Structure of conductive thin film

The conductive thin film of the present invention is formed on an anode corresponding to an electrode layer of a solar cell device or a light emitting device. Preferably, the electrode layer corresponds to at least one of a reflective electrode using Ag, a reflective electrode using Al, and a transparent electrode using ITO, and the coating agent according to the present invention is applied on the reflective electrode or the transparent electrode, As the coating agent is UV-cured, a conductive thin film may be formed on the electrode layer.

In the present invention, the work function can be controlled by adjusting the components of the ultraviolet curable binder and the metal oxide powder in the coating agent for producing such a conductive thin film. In addition, in the present invention, the work function can be controlled by adjusting the content of the solid powder of PEDOT:PSS in the coating agent for producing such a conductive thin film. For example, in the case of an OLED light emitting device, electrical properties related to the movement of charges are determined according to the properties of the hole transport layer and the light emitting layer. If the work function of the anode is controlled, the electrical efficiency can be optimized. However, electrical characteristics related to the movement of charges of the light emitting device may be different for each device, and thus the value of the optimized work function changes.

The present invention provides a coating agent having a target work function by simply adjusting the components of the coating agent, but having the effect of controlling the work function through a single process called UV curing after coating and a conductive thin film using the same.

Method for manufacturing a coating agent

The coating agent according to embodiments of the present invention is coated on the electrode layer of a solar cell or light emitting device to form a conductive thin film capable of controlling a work function on the electrode layer by UV curing, comprising: a UV curable binder; organic solvents; first dispersing aid; a second dispersing aid; metal oxide powder; and a solid powder of poly(3,4-ethylenedioxythiophene)-polystyrenesulfonic acid (PEDOT:PSS).

In the coating agent of the present invention, by adjusting the components of the ultraviolet curable binder and the metal oxide powder, the work function of the conductive thin film formed by UV curing of the coating agent can be controlled.

The metal oxide powder of the coating agent of the present invention is TiO ₂ , WO ₃ , ATO, CuO, MgO, Fe ₃ O ₄ , Fe ₂ O ₃ , CoFe ₂ O ₄ , NiFe ₂ O ₄ , and ZnFe ₂ O ₄ At least one of may include

In addition, the coating agent according to embodiments of the present invention is coated on the electrode layer of a solar cell or light emitting device, and is a coating agent capable of forming a conductive thin film capable of controlling a work function on the electrode layer by UV curing, comprising: a UV curable binder; organic solvents; first dispersing aid; a second dispersing aid; and metal oxide powder.

Preferably, the coating agent includes a photoinitiator, and more preferably, the photoinitiator includes 1.5 to 4.5% by weight of the total amount of the UV-curable binder.

In one embodiment of the present invention, the UV-curable binder included in the coating agent preferably includes an acrylic binder material. Such an acrylic binder can stably form a matrix in which the particles of the solid powder of PEDOT:PSS and the metal oxide powder can be located.

In one embodiment of the present invention, the UV-curable binder comprises (Hydroxyethyl)methacrylate (HEMA) 55 to 65% by weight, Pentaerythritol triacrylate (PETA) 34 to 44% by weight, and adhesion promoting acrylate oligomer 0.5 to 1.5% by weight . In another embodiment of the present invention, the ultraviolet curable binder is Melamine acrylate 45 to 55% by weight, Pentaerythritol triacrylate (PETA) 19 to 29% by weight, Trimethylolpropane triacrylate (TMPTA) 19 to 29% by weight, and Trifunctional Acid Ester 1 to 3% by weight. In another embodiment of the present invention, the UV-curable binder comprises 45 to 54% by weight of Hexafunctional Urethane Acrylate, 45 to 54% by weight of Nonafunctionla Urethane Acrylate, and 1 to 3% by weight of Trifunctional Acid Ester. However, the ultraviolet curable binder is not limited to the above composition.

Such an ultraviolet curable binder is preferably included in the coating agent in an amount of 0.5 to 5% by weight of the total weight of the coating agent. When the UV curable binder is less than 0.5% by weight, it is difficult to implement a binder matrix in which the particles of the solid powder of PEDOT:PSS and the particles of the metal oxide powder are evenly dispersed, and when it exceeds 5% by weight, the manufacturing process is difficult due to the high viscosity There is a problem in that economic efficiency is deteriorated because the amount of metal powder used is increased.

Meanwhile, the PEDOT:PSS according to an embodiment of the present invention has an ethylenedioxy group in the form of a ring in the structure of a thiophene, and has excellent stability against air or heat.

In addition, it has a lower optical band gap (760 nm to 780 nm or 1.6 eV to 1.7 eV) than thiophene due to the electron donating effect by the ethylenedioxy group substituted at positions 3 and 4, and depending on the potential difference of oxidation/reduction It is possible to change color, and in the oxidation state, the absorption band exists in the infrared region, so it is possible to secure transparency.

Preferably, PEDOT:PSS is in the form of a solid powder, and in one embodiment of the present invention, pallets (trade name: Orgacon Dry) provided by AGFA of Belgium may be used.

The solid powder of PEDOT:PSS is preferably included in the coating agent in an amount of 0.05 to 2% by weight based on the total weight of the coating agent. In the above content, the solid powder of PEDOT:PSS can evenly disperse the metal oxide powder contained in the coating agent, so that the work function can be uniformly controlled.

Meanwhile, various metal oxide powders may be used as the metal oxide powder according to the purpose of work function control.

In one embodiment of the present invention, the metal oxide powder is TiO ₂ , WO ₃ , ATO, CuO, MgO, Fe ₃ O ₄ , Fe ₂ O ₃ , CoFe ₂ O ₄ , NiFe ₂ O ₄ , and ZnFe ₂ O ₄ It may include one or more of

Alternatively, nanoparticles such as Co, CuOFe ₂ O ₃ , MgOFe ₂ O ₃ , MnBi, Ni, MnSb, MnOFe ₂ O ₃ , Y ₃ Fe ₅ O ₁₂ , CrO ₂ , MnAs, Gd, Dy, and EuO are oxidized It may correspond to metal powder.

The metal oxide powder is preferably included in the coating agent in an amount of 0.05 to 2% by weight of the total weight of the coating agent. In the above content, nanoparticles of metal oxide powder may be uniformly disposed on the matrix formed by the acrylic binder.

Preferably, the particle diameter of the metal oxide powder is 15 to 65 nm. As described above, since the metal oxide powder has a nanoparticle form, conductive particles of the metal oxide powder and the PEDOT:PSS powder are connected to realize a uniformly controlled work function.

As described above, the conductive thin film of the present invention is formed on an anode corresponding to an electrode layer of a solar cell device or a light emitting device, and the coating agent of the present invention is coated with the conductive thin film on the electrode layer through a single process called UV curing. can be easily formed.

At this time, in an embodiment of the present invention, when the coating agent is cured on the electrode layer, the conductive thin film is formed on the poly(3,4-ethylenedioxythiophene)-polystyrene on the matrix made of the ultraviolet curable binder material. It may have a structure in which the particles of the solid powder of sulfonic acid (PEDOT:PSS) and the particles of the metal oxide powder are connected to each other and dispersed.

On the other hand, in the present invention, a special dispersing aid is added to the coating agent in a predetermined amount. Specifically, the dispersion aid may include: a first dispersion aid for improving conductivity when the coating agent is coated on the electrode layer; and a second dispersing aid for assisting in dispersing the powder particles included in the coating agent.

In one embodiment of the present invention, the first dispersing aid may account for 2 to 6% by weight based on the total weight of the coating agent, and the second dispersing aid may account for 0.5 to 1.5% by weight based on the total weight of the coating agent.

The first dispersing aid is carbonate, diethylene glycol, propylene glycol, tetramethylene glycol, sorbitol, N,N-dimethylformamide (N,N) -dimethylformamide), ethylene glycol, N,N-dimethylacetamide, acetonitrile, dimethylsulfoxide, glycerol, ethylene cyanide ), formic acid, propylene carbonate, ethylene carbonate, 2,6-difluoropyridine, formamide, and N-methylformamide ( N-methylformamide), and the second dispersing aid preferably includes at least one of amines (Amines), acrylates (Acrylates), and polyols (polyols).

More preferably, the first dispersing aid includes carbonate, and the second dispersing aid includes amines. Or, more preferably, the first dispersing aid includes carbonate, and the second dispersing aid includes a tertiary amine.

That is, by adding the first dispersing aid and the second dispersing aid to the coating agent in the above range, the particles in the coating agent are effectively dispersed to form a conductive thin film having excellent conductivity. In addition, in an embodiment of the present invention, the diffuse reflection phenomenon that may be generated in the electrode layer may be eliminated by the combination of the components of the first dispersion aid and the second dispersion aid.

Meanwhile, in one embodiment of the present invention, the organic solvent is an amide solvent, nitromethane, ketone solvent, alcohol solvent, acetate solvent, aromatic solvent, glycol ether solvent, acrylate monomolecular solvent, amide solvent. , an acrylate oligomer, any one of urethane acrylate polymer, or a mixed solvent of the organic solvent.

More preferably, the organic solvent is ethanol, N,N-dimethylacetamide (DMA), nitromethane, methyl ethyl ketone (MEK (Methyl ethyl ketone)), isopropyl alcohol (Isopropyl alcohol), ethyl alcohol (Ethyl alcohol), n-butyl acetate, toluene, PGME (Propylene glycol methyl ether, 1-METHOXY-2-PROPANOL), PGMEA (Propylene glycol methyl ether acetate), HEMA (Hydroxyethyl methacrylate) ), Hydroxyethy acrylate (HEA), and N,N-dimethylformamide (N,N-dimethylform amide (DMF)), or a mixed solvent of the organic solvent.

Most preferably, the organic solvent may include ethanol and propylene glycol methyl ether (PGME). In the case of PGME, it is possible to more homogeneously disperse the metal oxide powder and the solid powder of PEDOT:PSS.

Such an organic solvent is preferably included in the coating agent in an amount of 80 to 98% by weight of the total weight of the coating agent. When the coating agent includes the organic solvent in the above range, it induces the prepared coating agent to stably maintain dispersion even after a long period of time.

However, despite the selection of the organic solvent as described above, since there is a problem that it is not completely dissolved in the organic solvent due to the characteristics of the solid powder of PEDOT:PSS, in the present invention, additional Agitation takes place.

Preferably, the coating agent according to an embodiment of the present invention is primarily a solid powder of the poly(3,4-ethylenedioxythiophene)-polystyrenesulfonic acid (PEDOT:PSS) and the metal oxide powder in an organic solvent. In this state, dispersion and mixing are performed by shearing force by a shear mixer including two or more rotors and stators, and secondarily, the poly(3,4-ethylenedioxythiophene)-polystyrenesulfonic acid ( Additional dispersion by a bead mill is performed in a state in which the solid powder of PEDOT:PSS) and the metal oxide powder are included.

Such a coating agent can form a conductive thin film on the electrode layer by a UV curing method with a thickness of 1 μm or less.

1 schematically shows a manufacturing step of a coating agent according to an embodiment of the present invention.

In step S100, a first mixture of a UV curable binder, an organic solvent, a first dispersing aid, and a second dispersing aid is prepared. The first mixture may include a photoinitiator. The first mixture prepared in this way may be agitated in general. In an embodiment of the present invention, the first mixture may be prepared by stirring the ultraviolet curable binder, the organic solvent, the first dispersing aid, and the second dispersing aid at 300 rpm for 1 hour.

In step S200, a second mixture obtained by mixing the solid powder of PEDOT:PSS with the first mixture is prepared. The second mixture prepared in this way may be agitated in general. In one embodiment of the present invention, the first mixture and the solid powder of PEDOT:PSS may be stirred at 300 rpm for 1 hour to prepare the second mixture.

Meanwhile, step S200 may be omitted according to an embodiment of the present invention. Accordingly, the coating agent may not include a solid powder of PEDOT:PSS according to an embodiment of the present invention.

In step S300, a third mixed solution obtained by mixing the metal oxide powder with the second mixed solution is prepared. The third mixture prepared in this way may be agitated in general. In one embodiment of the present invention, the third mixture may be prepared by stirring the second mixture and the metal oxide powder at 300 rpm for 1 hour.

On the other hand, when the above-described step S200 is omitted according to an embodiment of the present invention, the third mixture may be prepared by stirring the first mixture and the metal oxide powder at 300 rpm for 1 hour in the step S300.

In step S400, the third mixture may be pulverized by the shear mixer of the above-described method and stirred. In this case, the temperature of 5 to 12 ℃ is preferably maintained.

As an example of the shear mixer, a device including two or more rotors and a stator may be included to generate a high shear force using a high rotational force or the like. Such a shear mixer can more homogeneously prepare the third mixed solution by using the cavitation phenomenon. Preferably, with respect to the mixed solution, the shear mixer performs dispersion and mixing for 1 hour or more at a rotation speed of about 6,000 rpm or more. At this time, cooling is additionally performed so that the temperature of the mixed solution maintains the temperature range.

In step S500, the third mixture may be milled and stirred with the bead mill of the above-described method. In general, the solid powder of PEDOT:PSS is known as a material that does not dissolve in organic solvents, and most of them are prepared in the form of an aqueous solution. The solid powder of the PEDOT:PSS can be evenly dispersed by additional special stirring of the shear mixer and bead mill as described above.

Preferably, the bead mill is in the form of a bead mill capable of nano-dispersion. By this step S500, the third mixture may be more homogeneous by the beads and the dispersibility may be improved.

As an example of the bead mill, pulverization and dispersion are applied by applying an impact force to the target powder using an efficient bead, for example, a zirconia-containing bead in wet dispersion and wet grinding, and thus, the third mixture solution by this step S500 The silver beads can make it more homogeneous and improve dispersibility.

In addition, the beads preferably have a particle diameter of 50 to 200 μm, and more preferably, beads having a particle diameter in the range of 80 to 120 μm. The rotational speed of the rotating body of the bead mill is preferably used in a frequency range of about 30 to 60 Hz.

The coating prepared in this way should be stored in a refrigerated storage unit at 10° C. or less. When stored for a long time at room temperature of 20° C. or higher, the particles of the solid powder and metal oxide powder of PEDOT:PSS show aggregation, and the conductivity of the conductive thin film formed by the coating agent may be rapidly reduced.

Figure 2 schematically shows the state of the coating agent according to an embodiment of the present invention.

The part denoted by reference numeral 121 corresponds to a solvent including an organic solvent, an additive, and an ultraviolet curable binder, the part denoted by reference numeral 122 corresponds to metal oxide powder particles, and the part denoted by reference numeral 123 corresponds to poly ( It corresponds to solid powder particles of 3,4-ethylenedioxythiophene)-polystyrenesulfonic acid (PEDOT:PSS).

Figure 2(A) corresponds to a state in which the ultraviolet curable binder, organic solvent, and metal oxide powder are mixed with a shear mixer and bead mill, etc. without solid powder of PEDOT:PSS. Since the metal oxide powder has a property of cohesive to each other and has a high density, most of them are stirred and settled on the bottom after a certain period of time. In the case of performing UV curing of the coating agent in such a state, the metal oxide powder particles are not uniformly distributed, and accordingly, there is a problem that the work function may vary in a local area of the conductive thin film.

On the other hand, Figure 2 (B) corresponds to the state in which the solid powder of PEDOT:PSS, the ultraviolet curable binder, the organic solvent, and the metal oxide powder are mixed with a shear mixer and a bead mill, etc. stirred. Although the metal oxide powder has the property of aggregating with each other, it is bound to the solid powder particles of PEDOT:PSS and is homogeneously distributed in the matrix. In particular, since the solid powder particles of PEDOT:PSS have a low specific gravity, they are suspended in an organic solvent, thereby preventing aggregation of the metal oxide powder particles. Therefore, in the state of the coating agent, the particles of the metal oxide powder and the particles of the PEDOT:PSS powder are homogeneously dispersed, which can exert the effect of forming a conductive thin film having more homogeneous electrical properties in the area.

Figure 3 schematically shows the particle structure of the conductive thin film formed by the coating agent according to an embodiment of the present invention.

The portion indicated by reference numeral 124 corresponds to the matrix formed by the UV-curable binder, the portion indicated by reference numeral 122 corresponds to metal oxide powder particles, and the portion indicated by reference numeral 123 corresponds to poly (3,4-). Ethylenedioxythiophene)-polystyrenesulfonic acid (PEDOT:PSS) particles.

As shown in FIG. 3 , the conductive thin film has a form in which particles of metal oxide powder and particles of solid powder of PEDOT:PSS are atypically connected to each other on a matrix of an ultraviolet curable binder material. The ultraviolet curable binder stably fixes the metal oxide powder particles and the solid powder particles of PEDOT:PSS, and the particles of the metal oxide powder and the solid powder of PEDOT:PSS are uniformly distributed, but may have a structure connected to each other .

In such a structure, the connection between the metal oxide powder and the solid powder of PEDOT:PSS is stably maintained, and thus, stable work function control can be achieved.

Control of work function by controlling coating ingredients

The conductive thin film of the present invention may be formed by a coating agent, and more specifically, may be formed on an electrode layer corresponding to at least one of a reflective electrode using Ag, a reflective electrode using Al, and a transparent electrode using ITO. In this case, the conductive thin film may control the surface work function of the electrode layer according to the components of the ultraviolet curable binder and the metal oxide powder in the coating agent. In addition, the conductive thin film may control the surface work function of the electrode layer according to the content of the solid powder of PEDOT:PSS in the coating agent.

The coating agent according to an embodiment of the present invention can form a conductive thin film that controls the work function in the range of 4.5 to 4.8 eV on the electrode layer, and the electrode layer includes at least one of an Ag reflective electrode and an Al reflective electrode, , The coating agent may include a metal oxide powder including at least one of TiO ₂ , ATO, MgO, Fe ₃ O ₄ , NiFe ₂ O ₄ , and ZnFe ₂ O ₄ .

At this time, the coating agent is (Hydroxyethyl)methacrylate (HEMA) 55 to 65% by weight, Pentaerythritol triacrylate (PETA) 34 to 44% by weight, and adhesion promoting acrylate oligomer 0.5 to 1.5% by weight UV-curable binder, Melamine acrylate 45 to 55% by weight, Pentaerythritol triacrylate (PETA) 19 to 29% by weight, Trimethylolpropane triacrylate (TMPTA) 19 to 29% by weight, and Trifunctional Acid Ester 1 to 3% by weight UV curable binder, and Hexafunctional Urethane Acrylate 45 to 54 Weight%, 45 to 54% by weight of Nonafunctionla Urethane Acrylate, and 1 to 3% by weight of Trifunctional Acid Ester may include one or more of a UV curable binder.

In addition, the coating agent may contain 0.05 to 2% by weight of a solid powder of poly(3,4-ethylenedioxythiophene)-polystyrenesulfonic acid (PEDOT/PSS).

The coating agent according to an embodiment of the present invention can form a conductive thin film that controls the work function in the range of 4.9 to 5.2 eV on the electrode layer, and the electrode layer is one of an ITO transparent electrode, an Ag reflective electrode, and an Al reflective electrode. or more, wherein the coating agent comprises at least one of TiO ₂ , WO ₃ , ATO, CuO, MgO, Fe ₃ O ₄ , Fe ₂ O ₃ , CoFe ₂ O ₄ , NiFe ₂ O ₄ , and ZnFe ₂ O ₄ . It may include a metal oxide powder.

At this time, the coating agent is (Hydroxyethyl)methacrylate (HEMA) 55 to 65% by weight, Pentaerythritol triacrylate (PETA) 34 to 44% by weight, and adhesion promoting acrylate oligomer 0.5 to 1.5% by weight UV-curable binder, Melamine acrylate 45 to 55% by weight, Pentaerythritol triacrylate (PETA) 19 to 29% by weight, Trimethylolpropane triacrylate (TMPTA) 19 to 29% by weight, and Trifunctional Acid Ester 1 to 3% by weight UV curable binder, and Hexafunctional Urethane Acrylate 45 to 54 Weight%, 45 to 54% by weight of Nonafunctionla Urethane Acrylate, and 1 to 3% by weight of Trifunctional Acid Ester may include one or more of a UV curable binder.

In addition, the coating agent may contain 0.05 to 2% by weight of a solid powder of poly(3,4-ethylenedioxythiophene)-polystyrenesulfonic acid (PEDOT/PSS).

The coating agent according to an embodiment of the present invention can form a conductive thin film that controls the work function in the range of 5.3 to 5.6 eV on the electrode layer, and the electrode layer includes at least one of an ITO transparent electrode and an Ag reflective electrode, , The coating agent may include a metal oxide powder including at least one of ATO, CuO, MgO, Fe ₃ O ₄ , Fe ₂ O ₃ , CoFe ₂ O ₄ , NiFe ₂ O ₄ , and ZnFe ₂ O ₄ .

At this time, the coating agent is Melamine acrylate 45 to 55% by weight, Pentaerythritol triacrylate (PETA) 19 to 29% by weight, Trimethylolpropane triacrylate (TMPTA) 19 to 29% by weight, and Trifunctional Acid Ester 1 to 3% by weight UV-curable containing A binder, and 45 to 54% by weight of Hexafunctional Urethane Acrylate, 45 to 54% by weight of Nonafunctionla Urethane Acrylate, and 1 to 3% by weight of Trifunctional Acid Ester It may include one or more of an ultraviolet curable binder.

In addition, the coating agent may contain 0.05 to 2% by weight of a solid powder of poly(3,4-ethylenedioxythiophene)-polystyrenesulfonic acid (PEDOT/PSS).

The coating agent according to an embodiment of the present invention may form a conductive thin film controlled in the range of 5.7 to 5.9 eV on the electrode layer, and the electrode layer includes at least one of an Ag reflective electrode and an Al reflective electrode, and the coating agent ATO, and CoFe ₂ O ₄ may include a metal oxide powder containing at least one.

At this time, the coating agent is Melamine acrylate 45 to 55% by weight, Pentaerythritol triacrylate (PETA) 19 to 29% by weight, Trimethylolpropane triacrylate (TMPTA) 19 to 29% by weight, and Trifunctional Acid Ester 1 to 3% by weight UV-curable containing A binder, and 45 to 54% by weight of Hexafunctional Urethane Acrylate, 45 to 54% by weight of Nonafunctionla Urethane Acrylate, and 1 to 3% by weight of Trifunctional Acid Ester It may include one or more of an ultraviolet curable binder.

In addition, the coating agent may contain 0.05 to 2% by weight of a solid powder of poly(3,4-ethylenedioxythiophene)-polystyrenesulfonic acid (PEDOT/PSS).

As described above, the coating agent of the present invention can implement a conductive thin film that can control the work function by controlling the components of the ultraviolet curable binder and the metal oxide powder or by adjusting the content of the solid powder of PEDOT:PSS, and the conductive thin film on the electrode layer By forming , the work function can be controlled to have a desired work function.

On the other hand, as described above, when the conductive thin film is formed on the electrode layer by the coating agent of the present invention, the work function can be stably controlled.

Hereinafter, the experimental results on the effect of controlling the surface work function of the electrode layer according to the components of the coating agent will be described in detail.

Experiment 1: Effect of Work Function Control by Combination of UV-Curable Binder and Metal Oxide Powder

In this experiment, in the component of the coating agent capable of forming a conductive thin film, the effect of controlling the work function according to the combination of the ultraviolet curable binder and the metal oxide powder was checked. That is, the purpose of this study was to examine the effect of the composition of the ultraviolet curable binder and the metal oxide powder on the work function control effect of the conductive thin film.

In this experiment, a coating agent including an ultraviolet curable binder and metal oxide powder having various component combinations was prepared, respectively, and then a conductive thin film was formed on the electrode layers of various devices using the coating agent. At this time, the surface work function of the electrode layer by the conductive thin film was measured.

Table 1 below is a table of components of the UV-curable binder used in this experiment.

production example Furtherance One (Hydroxyethyl)methacrylate (HEMA) 60% by weight, Pentaerythritol triacrylate (PETA) 39% by weight, adhesion promoting acrylate oligomer 1% by weight 2 Melamine acrylate 50% by weight, Pentaerythritol triacrylate (PETA) 24% by weight, Trimethylolpropane triacrylate (TMPTA) 24% by weight, Trifunctional Acid Ester 2% by weight 3 Hexafunctional Urethane Acrylate 49% by weight, Nonafunctionla Urethane Acrylate 49% by weight, Trifunctional Acid Ester 2% by weight

In this experiment, the UV-curable binder of the above components was prepared by general stirring.

Table 2 below is a list of the metal oxide powder used in this experiment.

Types of metal oxide powder average particle size water TiO ₂ 18nm 99.90% WO ₃ 60nm 99.90% ATO 30nm 99.95% CuO 40nm 99% MgO 20nm 99%

In this experiment, a coating agent was prepared by combining the UV-curable binder shown in Table 1 and the metal oxide powder shown in Table 2. Table 3 below shows the components of the coating agent prepared by using various combinations of UV-curable binders and metal oxide powders.

production example bookbinder
production example PEDOT:PSS
solid powder content first
dispersion aid
(carbonate)
content second
dispersion aid
(amine)
content metal oxide powder organic solvent
content Kinds content Kinds content One One 2% 1.00% 4.00% 1.00% TiO ₂ 0.06% 91.94% 2 2 2% 1.00% 4.00% 1.00% TiO ₂ 0.06% 91.94% 3 3 2% 1.00% 4.00% 1.00% TiO ₂ 0.06% 91.94% 4 One 2% 1.00% 4.00% 1.00% WO ₃ 0.06% 91.94% 5 2 2% 1.00% 4.00% 1.00% WO ₃ 0.06% 91.94% 6 3 2% 1.00% 4.00% 1.00% WO ₃ 0.06% 91.94% 7 One 2% 1.00% 4.00% 1.00% ATO 0.06% 91.94% 8 2 2% 1.00% 4.00% 1.00% ATO 0.06% 91.94% 9 3 2% 1.00% 4.00% 1.00% ATO 0.06% 91.94% 10 One 2% 1.00% 4.00% 1.00% CuO 0.06% 91.94% 11 2 2% 1.00% 4.00% 1.00% CuO 0.06% 91.94% 12 3 2% 1.00% 4.00% 1.00% CuO 0.06% 91.94% 13 One 2% 1.00% 4.00% 1.00% MgO 0.06% 91.94% 14 2 2% 1.00% 4.00% 1.00% MgO 0.06% 91.94% 15 3 2% 1.00% 4.00% 1.00% MgO 0.06% 91.94%

In this experiment, the coating agent of the above components was prepared to be used in the spin coating process and the UV curing process. More specifically, the coating agent was prepared according to the manufacturing steps shown in FIG. 1. In this case, 3 wt% of the UV curing initiator was used based on the total amount of the UV curing binder, and the organic solvent was ethanol and PGME in a ratio of 50:50. A mixture of solvents mixed in proportions was used.

In addition, in this experiment, the coating agent was applied to the surface of various electrode layers using a spin coating process, and then a conductive thin film was formed through an ultraviolet curing process. More specifically, the coating agent is spin-coated on the surface of the electrode layer for 20 seconds at 3000 rpm and then dried in an oven at 90° C. for 2 minutes, and then UV-cured at a light amount of 400 mJ/cm ² to make the conductive thin film was formed.

In this case, the electrode layer may include one of an Ag reflective electrode having a surface work function value of 4.87 eV, an Al reflective electrode having a surface work function value of 4.81 eV, and an ITO transparent electrode having a surface work function value of 5.19 eV. can In this experiment, the surface work function value was measured using a Photoelectron spectrometer (model name: AC-2) manufactured by Riken.

That is, in this experiment, a coating agent having various components was prepared through Preparation Examples 1 to 15 described in Table 3, and it was applied to the surface of each electrode layer including the Ag reflective electrode, the Al reflective electrode, and the ITO transparent electrode to conduct conductivity. A thin film was formed. Table 4 below shows the surface work function values of the electrode layers according to Examples.

Example Coating preparation example electrode layer Surface work function (eV) One One Ag reflective electrode 5.15 2 2 Ag reflective electrode 5.11 3 3 Ag reflective electrode 5.17 4 One Al reflective electrode 4.89 5 2 Al reflective electrode 4.93 6 3 Al reflective electrode 4.87 7 One ITO transparent electrode 5.09 8 2 ITO transparent electrode 5.13 9 3 ITO transparent electrode 5.14 10 4 Ag reflective electrode 5.09 11 5 Ag reflective electrode 5.21 12 6 Ag reflective electrode 5.1 13 4 Al reflective electrode 5.01 14 5 Al reflective electrode 5.07 15 6 Al reflective electrode 5.00 16 4 ITO transparent electrode 5.12 17 5 ITO transparent electrode 5.09 18 6 ITO transparent electrode 5.06 19 7 Ag reflective electrode 5.04 20 8 Ag reflective electrode 5.17 21 9 Ag reflective electrode 5.22 22 7 Al reflective electrode 5.17 23 8 Al reflective electrode 5.15 24 9 Al reflective electrode 5.09 25 7 ITO transparent electrode 5.24 26 8 ITO transparent electrode 5.11 27 9 ITO transparent electrode 5.21 28 10 Ag reflective electrode 5.22 29 11 Ag reflective electrode 5.28 30 12 Ag reflective electrode 5.33 31 10 Al reflective electrode 5.24 32 11 Al reflective electrode 5.27 33 12 Al reflective electrode 5.16 34 10 ITO transparent electrode 5.12 35 11 ITO transparent electrode 5.15 36 12 ITO transparent electrode 5.12 37 13 Ag reflective electrode 4.85 38 14 Ag reflective electrode 5.23 39 15 Ag reflective electrode 5.26 40 13 Al reflective electrode 4.79 41 14 Al reflective electrode 5.03 42 15 Al reflective electrode 5.11 43 13 ITO transparent electrode 5.1 44 14 ITO transparent electrode 5.26 45 15 ITO transparent electrode 5.33

As shown in Table 4, after forming a conductive thin film on each of the Ag reflective electrode, the Al reflective electrode, and the ITO transparent electrode using each of the coating agents prepared by varying the component combinations of the ultraviolet curable binder and the metal oxide powder, the surface work function value As a result of measuring , it can be confirmed that the surface work function value is controlled in the range of 4.79 to 5.33 eV.

4 is a graph showing a surface work function of an electrode layer on which a conductive thin film is formed according to an embodiment of the present invention. As shown in FIG. 4 , it can be seen that the surface work function values of the electrode layers according to Examples 1 to 45 were controlled in the range of 4.79 to 5.33 eV, and the range of the work function values controlled by the conductive thin film was relatively narrow. can check that

That is, through Experiment 1 as above, it can be determined that the conductive thin film can control the work function of the electrode layer according to the component combination of the ultraviolet curable binder and the metal oxide powder.

Experiment 2: Effect of controlling work function according to the inclusion of solid powder of PEDOT:PSS

In this experiment, in the components of the coating agent capable of forming a conductive thin film, the effect of controlling the work function according to the inclusion of solid powder of PEDOT:PSS was checked. That is, it was attempted to confirm the effect of the solid powder of PEDOT:PSS on the work function control effect of the conductive thin film.

In this experiment, a coating agent containing a solid powder of PEDOT:PSS and a coating agent not containing a solid powder of PEDOT:PSS were prepared, respectively, and then a conductive thin film was formed on the electrode layers of various devices using the coating agent. The coating agent may be prepared according to a plurality of embodiments including a combination of various components of an ultraviolet curable binder and metal oxide powder. Then, the surface work function of the electrode layer by the conductive thin film was measured.

In this case, the coating agent may include a combination of the ultraviolet curable binder shown in Table 1, and the metal oxide powder shown in Table 5 below.

Types of metal oxide powder average particle size water ATO 30nm 99.95% Fe ₃ O ₄ 20nm 99.50% Fe ₂ O ₃ 20nm 99.50% CoFe ₂ O ₄ 30nm 99.90% NiFe ₂ O ₄ 30nm 98% ZnFe ₂ O ₄ 30nm 98.50%

Table 6 below shows the components of the coating agent prepared through this experiment.

production example bookbinder
production example PEDOT:PSS
solid powder content first
dispersion aid
(carbonate)
content second
dispersion aid
(amine)
content metal oxide powder organic solvent
content Kinds content Kinds content 16 2 2% 0% 4.00% 1.00% ATO 0.06% 92.94% 17 2 2% 0.06% 4.00% 1.00% ATO 0.06% 92.88% 18 3 2% 0% 4.00% 1.00% Fe ₃ O ₄ 0.06% 92.94% 19 3 2% 0.06% 4.00% 1.00% Fe ₃ O ₄ 0.06% 92.88% 20 3 2% 0% 4.00% 1.00% Fe ₂ O ₃ 0.06% 92.94% 21 3 2% 0.06% 4.00% 1.00% Fe ₂ O ₃ 0.06% 92.88% 22 3 2% 0% 4.00% 1.00% CoFe ₂ O ₄ 0.06% 92.94% 23 3 2% 0.06% 4.00% 1.00% CoFe ₂ O ₄ 0.06% 92.88% 24 3 2% 0% 4.00% 1.00% NiFe ₂ O ₄ 0.06% 92.94% 25 3 2% 0.06% 4.00% 1.00% NiFe ₂ O ₄ 0.06% 92.88% 26 3 2% 0% 4.00% 1.00% ZnFe ₂ O ₄ 0.06% 92.94% 27 3 2% 0.06% 4.00% 1.00% ZnFe ₂ O ₄ 0.06% 92.88%

That is, the coating agent in this experiment may or may not include the solid powder of PEDOT:PSS. In this experiment, the coating agent of the above components was prepared to be used in the spin coating process and the UV curing process. More specifically, when the coating agent contains a solid powder of PEDOT:PSS, the coating agent was prepared according to the manufacturing step shown in FIG. 1, and when the coating agent does not include a solid powder of PEDOT:PSS, FIG. The coating agent was prepared by omitting step S200 from the manufacturing steps shown in 1 .

In this case, the UV curing initiator used 3 wt% of the total amount of the UV curing binder, and the organic solvent was a solvent mixture in which ethanol and PGME were mixed in a ratio of 50:50.

In addition, in this experiment, the coating agent was applied to the surface of various electrode layers using a spin coating process, and then a conductive thin film was formed through an ultraviolet curing process. More specifically, the coating agent is spin-coated on the surface of the electrode layer for 20 seconds at 3000 rpm and then dried in an oven at 90° C. for 2 minutes, and then UV-cured at a light amount of 400 mJ/cm ² to make the conductive thin film was formed.

In this case, the electrode layer may include one of an Ag reflective electrode having a surface work function value of 4.87 eV, an Al reflective electrode having a surface work function value of 4.81 eV, and an ITO transparent electrode having a surface work function value of 5.19 eV. can In this experiment, the surface work function value was measured using a Photoelectron spectrometer (model name: AC-2) manufactured by Riken.

That is, in this experiment, a coating agent having various components was prepared through Preparation Examples 16 to 27 described in Table 6, and this was applied to the surface of each electrode layer including the Ag reflective electrode, the Al reflective electrode, and the ITO transparent electrode to conduct conductivity. A thin film was formed. Table 7 below shows the surface work function values of the electrode layers according to Examples.

Example Coating preparation example electrode layer Surface work function (eV) 46 16 Ag reflective electrode 5.73 47 16 Al reflective electrode 4.59 48 16 ITO transparent electrode N/A 49 17 Ag reflective electrode 5.61 50 17 Al reflective electrode 4.57 51 17 ITO transparent electrode 5.51 52 18 Ag reflective electrode 5.12 53 18 Al reflective electrode 4.62 54 18 ITO transparent electrode 5.52 55 19 Ag reflective electrode 5.16 56 19 Al reflective electrode 5.29 57 19 ITO transparent electrode 5.33 58 20 Ag reflective electrode 5.13 59 20 Al reflective electrode 5.07 60 20 ITO transparent electrode N/A 61 21 Ag reflective electrode 5.25 62 21 Al reflective electrode 5.22 63 21 ITO transparent electrode 5.55 64 22 Ag reflective electrode 5.07 65 22 Al reflective electrode 4.93 66 22 ITO transparent electrode N/A 67 23 Ag reflective electrode 4.94 68 23 Al reflective electrode 5.88 69 23 ITO transparent electrode 5.54 70 24 Ag reflective electrode 4.95 71 24 Al reflective electrode 4.96 72 24 ITO transparent electrode N/A 73 25 Ag reflective electrode 4.97 74 25 Al reflective electrode 4.83 75 25 ITO transparent electrode 5.52 76 26 Ag reflective electrode 4.86 77 26 Al reflective electrode 4.92 78 26 ITO transparent electrode N/A 79 27 Ag reflective electrode 4.85 80 27 Al reflective electrode 4.85 81 27 ITO transparent electrode 5.52

As shown in Table 7, the surface work function value was measured after forming a conductive thin film on each of the Ag reflective electrode, Al reflective electrode, and ITO transparent electrode using each of the coating agents prepared by varying the inclusion of solid powder of PEDOT:PSS. As a result, it can be seen that the surface work function value is controlled in the range of 4.57 to 5.88 eV.

5 is a graph showing a surface work function of an electrode layer on which a conductive thin film is formed according to an embodiment of the present invention. As shown in FIG. 5 , it can be seen that the surface work function values of the electrode layers according to Examples 46 to 81 were controlled in the range of 4.57 to 5.88 eV, and the range of the work function values controlled by the conductive thin film was relatively wide. can check that

That is, through Experiment 2 as above, it can be determined that the conductive thin film can control the work function of the electrode layer according to the presence or absence of the solid powder of PEDOT:PSS.

Through the experimental results of Experiments 1 and 2, the coating agent capable of producing a conductive thin film capable of controlling the work function based on the selection of the containing metal according to an embodiment of the present invention can be obtained by adjusting the components of the ultraviolet curable binder and the metal oxide powder. You can see that the function can be controlled. In addition, it can be confirmed that the work function can be controlled by adjusting the content of the solid powder of PEDOT:PSS.

In addition, through the experimental results of Experiments 1 and 2, the coating agent capable of producing a conductive thin film capable of controlling the work function based on the selection of the containing metal selectively includes a UV-curable binder and components of the metal oxide powder to form an opaque electrode and a transparent electrode. It can be confirmed that a conductive thin film capable of controlling the work function can be formed on the electrode layer including

Preferably, the coating agent according to an embodiment of the present invention can control the work function in the range of 4.5 to 4.8 eV on the electrode layer, and the electrode layer includes at least one of an Ag reflective electrode and an Al reflective electrode, The coating agent may include a metal oxide powder including at least one of TiO ₂ , ATO, MgO, Fe ₃ O ₄ , NiFe ₂ O ₄ , and ZnFe ₂ O ₄ .

At this time, the coating agent is (Hydroxyethyl)methacrylate (HEMA) 55 to 65% by weight, Pentaerythritol triacrylate (PETA) 34 to 44% by weight, and adhesion promoting acrylate oligomer 0.5 to 1.5% by weight UV-curable binder, Melamine acrylate 45 to 55% by weight, Pentaerythritol triacrylate (PETA) 19 to 29% by weight, Trimethylolpropane triacrylate (TMPTA) 19 to 29% by weight, and Trifunctional Acid Ester 1 to 3% by weight UV curable binder, and Hexafunctional Urethane Acrylate 45 to 54 Weight%, 45 to 54% by weight of Nonafunctionla Urethane Acrylate, and 1 to 3% by weight of Trifunctional Acid Ester may include at least one of a UV curable binder.

In addition, the coating agent may contain 0.05 to 2% by weight of a solid powder of poly(3,4-ethylenedioxythiophene)-polystyrenesulfonic acid (PEDOT/PSS).

Preferably, the coating agent according to an embodiment of the present invention can form a conductive thin film that controls the work function in the range of 4.9 to 5.2 eV on the electrode layer, and the electrode layer is an ITO transparent electrode, Ag reflective electrode, and Al and at least one of the reflective electrodes, wherein the coating agent is selected from among TiO ₂ , WO ₃ , ATO, CuO, MgO, Fe ₃ O ₄ , Fe ₂ O ₃ , CoFe ₂ O ₄ , NiFe ₂ O ₄ , and ZnFe ₂ O ₄ . It may include a metal oxide powder containing one or more.

At this time, the coating agent is (Hydroxyethyl)methacrylate (HEMA) 55 to 65% by weight, Pentaerythritol triacrylate (PETA) 34 to 44% by weight, and adhesion promoting acrylate oligomer 0.5 to 1.5% by weight UV-curable binder, Melamine acrylate 45 to 55% by weight, Pentaerythritol triacrylate (PETA) 19 to 29% by weight, Trimethylolpropane triacrylate (TMPTA) 19 to 29% by weight, and Trifunctional Acid Ester 1 to 3% by weight UV curable binder, and Hexafunctional Urethane Acrylate 45 to 54 Weight%, 45 to 54% by weight of Nonafunctionla Urethane Acrylate, and 1 to 3% by weight of Trifunctional Acid Ester may include at least one of a UV curable binder.

In addition, the coating agent may contain 0.05 to 2% by weight of a solid powder of poly(3,4-ethylenedioxythiophene)-polystyrenesulfonic acid (PEDOT/PSS).

Preferably, the coating agent according to an embodiment of the present invention can form a conductive thin film that controls the work function in the range of 5.3 to 5.6 eV on the electrode layer, and the electrode layer is one of an ITO transparent electrode and an Ag reflective electrode Including the above, wherein the coating agent includes a metal oxide powder comprising at least one of ATO, CuO, MgO, Fe ₃ O ₄ , Fe ₂ O ₃ , CoFe ₂ O ₄ , NiFe ₂ O ₄ , and ZnFe ₂ O ₄ can do.

At this time, the coating agent is Melamine acrylate 45 to 55% by weight, Pentaerythritol triacrylate (PETA) 19 to 29% by weight, Trimethylolpropane triacrylate (TMPTA) 19 to 29% by weight, and Trifunctional Acid Ester 1 to 3% by weight UV-curable containing A binder, and 45 to 54% by weight of Hexafunctional Urethane Acrylate, 45 to 54% by weight of Nonafunctionla Urethane Acrylate, and 1 to 3% by weight of Trifunctional Acid Ester It may include one or more of an ultraviolet curable binder.

In addition, the coating agent may contain 0.05 to 2% by weight of a solid powder of poly(3,4-ethylenedioxythiophene)-polystyrenesulfonic acid (PEDOT/PSS).

Preferably, the coating agent according to an embodiment of the present invention can form a conductive thin film controlled in a range of 5.7 to 5.9 eV on the electrode layer, and the electrode layer includes at least one of an Ag reflective electrode and an Al reflective electrode And, the coating agent may include a metal oxide powder comprising at least one of ATO, and CoFe ₂ O ₄ .

At this time, the coating agent is Melamine acrylate 45 to 55% by weight, Pentaerythritol triacrylate (PETA) 19 to 29% by weight, Trimethylolpropane triacrylate (TMPTA) 19 to 29% by weight, and Trifunctional Acid Ester 1 to 3% by weight UV-curable containing A binder, and 45 to 54% by weight of Hexafunctional Urethane Acrylate, 45 to 54% by weight of Nonafunctionla Urethane Acrylate, and 1 to 3% by weight of Trifunctional Acid Ester It may include one or more of an ultraviolet curable binder.

In addition, the coating agent may contain 0.05 to 2% by weight of a solid powder of poly(3,4-ethylenedioxythiophene)-polystyrenesulfonic acid (PEDOT/PSS).

The description of the presented embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the scope of the invention. Thus, the present invention is not to be limited to the embodiments presented herein, but is to be construed in the widest scope consistent with the principles and novel features presented herein.

Claims (10)

A coating agent that is coated on the electrode layer of a solar cell or light emitting device to form a conductive thin film capable of controlling a work function on the electrode layer by UV curing,
UV curable binder;
organic solvents;
first dispersing aid;
a second dispersing aid;
metal oxide powder; and
Poly (3,4-ethylenedioxythiophene)-polystyrene sulfonic acid (PEDOT: PSS) solid powder; contains,
The work function is controlled by adjusting the components of the ultraviolet curable binder and the metal oxide powder,
The metal oxide powder includes at least one of TiO ₂ , WO ₃ , ATO, CuO, MgO, Fe ₃ O ₄ , Fe ₂ O ₃ , CoFe ₂ O ₄ , NiFe ₂ O ₄ , and ZnFe ₂ O ₄ , a coating agent .
The method according to claim 1,
The coating agent may form a conductive thin film that controls the work function in the range of 4.5 to 4.8 eV on the electrode layer,
The electrode layer includes at least one of Ag reflective electrode and Al reflective electrode, and the coating agent includes at least one of TiO ₂ , ATO, MgO, Fe ₃ O ₄ , NiFe ₂ O ₄ , and ZnFe ₂ O ₄ Oxidation containing A coating agent comprising a metal powder.
The method according to claim 1,
The coating agent can form a conductive thin film that controls the work function in the range of 4.9 to 5.2 eV on the electrode layer,
The electrode layer includes at least one of an ITO transparent electrode, an Ag reflective electrode, and an Al reflective electrode, and the coating agent is TiO ₂ , WO ₃ , ATO, CuO, MgO, Fe ₃ O ₄ , Fe ₂ O ₃ , CoFe ₂ O ₄ , NiFe ₂ O ₄ , and a coating agent comprising a metal oxide powder comprising at least one of ZnFe ₂ O ₄ .
The method according to claim 1,
The coating agent may form a conductive thin film that controls the work function in the range of 5.3 to 5.6 eV on the electrode layer,
The electrode layer includes at least one of an ITO transparent electrode and an Ag reflective electrode, and the coating agent is ATO, CuO, MgO, Fe ₃ O ₄ , Fe ₂ O ₃ , CoFe ₂ O ₄ , NiFe ₂ O ₄ , and ZnFe ₂ O ₄ Containing a metal oxide powder comprising at least one of, a coating agent.
The method according to claim 1,
The coating agent may form a conductive thin film controlled in the range of 5.7 to 5.9 eV on the electrode layer,
The electrode layer includes at least one of an Ag reflective electrode and an Al reflective electrode, and the coating agent comprises a metal oxide powder comprising at least one of ATO, and CoFe ₂ O ₄ .
The method according to claim 1,
When the coating agent is cured on the electrode layer, the conductive thin film is a solid powder of the poly(3,4-ethylenedioxythiophene)-polystyrenesulfonic acid (PEDOT:PSS) on a matrix made of the ultraviolet curable binder material. And, the coating agent having a structure in which the particles of the metal oxide powder are connected to each other and dispersed.
The method according to claim 1,
The metal oxide powder accounts for 0.05 to 2% by weight based on the total weight of the coating agent, the coating agent.
The method according to claim 1,
The coating agent,
0.5 to 5% by weight of an ultraviolet curable binder;
80 to 98% by weight of an organic solvent;
2 to 6% by weight of the first dispersing aid;
0.5 to 1.5% by weight of the second dispersing aid;
0.05 to 2% by weight of metal oxide powder; and
A coating agent comprising a; 0.05 to 2% by weight of poly(3,4-ethylenedioxythiophene)-polystyrenesulfonic acid (PEDOT/PSS) solids powder.
The method according to claim 1,
The coating agent,
A shear mixer including two or more rotors and a stator in a state where the solid powder of the poly(3,4-ethylenedioxythiophene)-polystyrenesulfonic acid (PEDOT:PSS) and the metal oxide powder are primarily contained in an organic solvent Dispersion and mixing by shear force by In which additional dispersion by a bead mill is performed, the coating agent.
A method of manufacturing a coating agent that is coated on the electrode layer of a solar cell or light emitting device to form a conductive thin film capable of controlling a work function on the electrode layer by UV curing,
preparing a first mixture by mixing an ultraviolet curable binder, an organic solvent, a first dispersing aid, and a second dispersing aid;
preparing a second mixture by mixing a solid powder of poly(3,4-ethylenedioxythiophene)-polystyrenesulfonic acid (PEDOT:PSS) with the first mixture;
preparing a third mixture by mixing the metal oxide powder with the second mixture;
pulverizing the third mixture with a shear mixer to perform stirring; and
Including; milling the third mixture with a bead mill to perform stirring;
The work function is controlled by adjusting the components of the ultraviolet curable binder and the metal oxide powder,
The metal oxide powder includes at least one of TiO ₂ , WO ₃ , ATO, CuO, MgO, Fe ₃ O ₄ , Fe ₂ O ₃ , CoFe ₂ O ₄ , NiFe ₂ O ₄ , and ZnFe ₂ O ₄ , conductivity A method for preparing a coating capable of forming a thin film.

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