KR101298026B1 - Fabrication method of photo active layer for solar cell - Google Patents

Abstract

PURPOSE: A manufacturing method of a solar battery is provided to manufacture a photoactive layer based on a single phase semiconductor compound, which has dense and coarse grains, through a low temperature heat treatment of 550 °C or less. CONSTITUTION: An ink comprises a copper nanoparticle and a chalcogen compound particle of one or more elements selected from group 12-14. A manufacturing method of a solar cell photoactive layer comprises a step of forming a coating film by spreading ink which contains the copper nanoparticle and the chalcogen compound particle; and a step of manufacturing a copper and chalcogen compound layer by heat-treating the coating layer. The group 12 includes Zn, the group 13 is one or more selected from indium and gallium, the group 14 includes Sn, and the chalcogen element is one or more selected from sulfur and selenium.

Description

[0001] The present invention relates to a photovoltaic layer,

The present invention relates to a method of manufacturing a photoactive layer of a solar cell, and more particularly, to a method of manufacturing a photoactive layer of a compound semiconductor based solar cell.

The manufacturing process of the compound semiconductor photoactive layer (CIG (S, Se), CZT (S, Se)) based on the existing vapor deposition method has a limitation in that a high processing cost is required despite its excellent characteristics. Thus, in order to commercialize a solar cell using a compound semiconductor, it is considered to be essential technology to manufacture CIG (S, Se) and CZT (S, Se) photoactive layers using a solution process.

 US 6,127,202 and US 6268014, a mixture of metal oxide nanoparticles or a mixture of metal oxide and non-oxide particles is coated on a substrate and reacted in a reducing atmosphere and a Se gas atmosphere to form a CI (G ) S films have been attempted by a particle - based solution process.

However, when a photoactive layer is prepared using a metal oxide-based solution process, an incidental reduction process must be performed, and there is a problem that defects are generated in the reduction process, which causes non-uniformity of reaction in the Se gas heat treatment process .

Therefore, it is necessary to research and develop a new economical approach to produce a single-phase CIG (S, Se) and CZT (S, Se) membranes by performing heat treatment at or near the process tolerance temperature of 550 ° C.

U.S. Patent 6,127,202 U.S. Patent No. 6268014

It is an object of the present invention to provide an ink capable of producing a dense, single-phase semiconductor compound based photoactive layer having coarse grains through a low temperature heat treatment below a process tolerance of 550 ° C.

It is another object of the present invention to provide a method for producing a single-phase semiconductor compound-based photoactive layer having a dense, coarse grain through low temperature heat treatment of 550 ° C. or lower, which is a process tolerance temperature, and a photoactive layer.

The ink according to the present invention contains copper nanoparticles; and chalcogenide particles of one or more elements selected from Groups 12 to 14.

The ink according to an embodiment of the present invention may be an ink for a photoactive layer of a solar cell.

Method for manufacturing a photovoltaic layer of a solar cell according to the present invention comprises the steps of: a) copper nanoparticles; and a coating film is formed by applying an ink containing chalcogenide compound particles of one or more elements selected from Group 12 to Group 14 on a substrate ; And b) heat-treating the coating film to produce a multi-element chalcogenide film of one or more selected elements from copper and Groups 12-14.

In the method of manufacturing a solar cell photoactive layer according to an embodiment of the present invention, Group 12 includes zinc (Zn), Group 13 is one or more selected from indium and gallium, Group 14 includes Sn, knife The cogen element may be selected from one or more of sulfur and selenium.

In the method of manufacturing a photovoltaic cell active layer according to an embodiment of the present invention, the chalcogenide particles may include chalcogenide (S and / or Se) compound particles of one or more elements selected from In and Ga. In one example, the chalcogenide particles are (In _x Ga _1-x ) ₄ (S _y Se _1-y ) ₃ , (In _x Ga _1-x ) (S _y Se _1-y ), (In _x Ga _{1- x} ) ₆ (S _y Se _1-y ) ₇ , (In _x Ga _1-x ) ₉ (S _y Se _1-y ) ₁₁ , (In _x Ga _1-x ) ₂ (S _y Se _1-y ) ₃ And one or more particles selected from (In _x Ga _1-x ) ₅ (S _y Se _1-y ) ₇ . In this case, in the chalcogenide particles, x may be a real number of 0 ≦ x ≦ 1, and y may be a real number of 0 ≦ y ≦ 1.

In the method of manufacturing a solar cell photoactive layer according to an embodiment of the present invention, the chalcogenide particles may include chalcogenide (S and / or Se) compound particles of at least one element selected from Sn and Zn. For example, one or more particles selected from Sn (S _y Se _1-y ), Sn ₂ (S _y Se _1-y ) _3, and Sn (S _y Se _1-y ) ₂ and Zn (S _y Se _{1- y} ) a mixture of particles. At this time, in the chalcogenide particles, y is a real number of 0 ≦ y ≦ 1.

In the method of manufacturing a solar cell photoactive layer according to an embodiment of the present invention, the molar ratio of one or more elements selected from group 12 to 14 contained in the ink: copper may be 1: 0.7 to 1.2.

In the method of manufacturing the solar cell photoactive layer according to an embodiment of the present invention, the heat treatment may be performed at 400 to 550 ° C.

In the method of manufacturing the solar cell photoactive layer according to an embodiment of the present invention, the heat treatment may be performed in a chalcogen atmosphere.

In the method of manufacturing the solar cell photoactive layer according to an embodiment of the present invention, a single phase polychalcogen compound may be formed by heat treatment.

In the method of manufacturing a photovoltaic cell active layer according to an embodiment of the present invention, the copper nanoparticles are acid and amine prepared by heating and stirring a copper precursor solution containing a copper precursor, an acid and an amine, and then injecting a reducing agent. It may be capped copper nanoparticles.

The present invention includes a solar cell photoactive layer produced by the above-described method for manufacturing a solar cell photoactive layer.

The present invention includes a solar cell provided with a photoactive layer of a solar cell manufactured by the above-described method for manufacturing a photoactive layer of a solar cell.

The method of manufacturing a photoactive layer according to the present invention is a high quality poly-chalcogen compound (photoactive layer) by applying an ink containing copper nanoparticles and chalcogen compound particles and performing a low temperature heat treatment of the coating film. ) Can be prepared, and a photoactive layer made of a single phase polychalcogen compound can be prepared at a low temperature of 550 ° C. or lower, and has excellent uniformity, a fine microstructure, and a micrometer order size. There is an advantage that can produce a photoactive layer consisting of coarse grains having.

1 is a diagram showing an X-ray diffraction pattern of Cu nanoparticles synthesized in the preparation example,
2 is a view showing a scanning electron micrograph of Cu nanoparticles synthesized in Preparation Example,
3 is a view showing a scanning electron micrograph of In ₂ Se ₃ synthesized in the preparation example,
4 is a view showing an X-ray diffraction pattern of the photoactive layer prepared in Preparation Example,
5 is a view showing a scanning electron micrograph of the photoactive layer prepared in Preparation Example,
FIG. 6 is a diagram illustrating an X-ray diffraction pattern of CuInSe ₂ particles prepared in Comparative Example,
7 is a view showing a scanning electron micrograph of the CuInSe ₂ particles prepared in the comparative example,
8 is a scanning electron micrograph of the cross section of the photoactive layer prepared in Comparative Example.

Hereinafter, a method of manufacturing the ink and photoactive layer of the present invention will be described in detail with reference to the accompanying drawings. The following drawings are provided by way of example so that those skilled in the art can fully understand the spirit of the present invention. Therefore, the present invention is not limited to the following drawings, but may be embodied in other forms, and the following drawings may be exaggerated in order to clarify the spirit of the present invention. Hereinafter, the technical and scientific terms used herein will be understood by those skilled in the art without departing from the scope of the present invention. Descriptions of known functions and configurations that may be unnecessarily blurred are omitted.

As a result of deepening the research on the compound semiconductor-based solar cell photoactive layer, the applicant has mixed and heat-treated the chalcogenide compound particles between the copper of the nanoparticles and the elements constituting the photoactive layer to be manufactured except copper. The low temperature heat treatment below 550 ℃, which is the process tolerance temperature, enables the production of high quality photoactive layers, the photoactive layer consisting of a single-phase polychalcogen compound can be prepared, and the compact photoactive layer can be produced. It has been found that the photoactive layer made can be produced, and thus the present invention has been filed.

The ink according to the present invention contains copper nanoparticles; and chalcogenide particles of one or two or more elements selected from Groups 12 to 14; At this time, the ink of the present invention may be an ink for a photoactive layer of a solar cell.

Specifically, copper contained in the ink is nanoparticles having a nano size to obtain sintering driving force and low temperature reactivity with chalcogenide particles. As a practical example, the copper nanoparticles may have an average particle size of 5 to 200 nm, and may have a uni-modal, bi-modal or higher distribution. In this case, when the bimodal or more distribution has a center of each peak in the distribution may be independently 5 to 200nm.

In detail, the chalcogenide particles contained in the ink are chalcogenide particles containing all of the elements constituting the photoactive layer to be manufactured except copper.

For example, when the photoactive layer to be manufactured is CI (S, Se) (Cu-In- (S, Se)), the chalcogenide particles may be chalcogenide particles containing In. As a practical example, the chalcogen compound particles containing In may be In-Se compound particles, In-S compound particles, or In-Se-S compound particles.

For example, when the photoactive layer to be manufactured is CIG (S, Se) (Cu-In-Ga- (S, Se)), the chalcogenide particles may be chalcogenide particles containing In—Ga. As a practical example, the chalcogen compound particles containing In-Ga may be In-Ga-Se compound particles, In-Ga-S compound particles or In-Ga-Se-S compound particles.

 For example, when the photoactive layer to be prepared is CZT (S, Se) (Cu-Zn-Sn- (S, Se)), the chalcogenide particles may be chalcogenide particles containing Zn and Sn. As a practical example, the chalcogenide compound particles containing Zn and Sn may contain at least one selected from Sn-Se compound particles, Sn-S compound particles and Sn-Se-S compound particles and Zn-S compound particles, Zn- Particles and Zn-Se-S compound particles.

As a practical example, the chalcogenide particles include (In _x Ga _1-x ) ₄ (S _y Se _1-y ) ₃ , (In _x Ga _1-x ) (S _y Se _1-y ), (In _x Ga _{1 -x} ) ₆ (S _y Se _1-y ) ₇ , (In _x Ga _1-x ) ₉ (S _y Se _1-y ) ₁₁ , (In _x Ga _1-x ) ₂ (S _y Se _1-y ) ₃ and (In _x Ga _1-x ) ₅ (S _y Se _1-y ) ₇ may include one or more selected particles. In this case, in the chalcogenide particles, x may be a real number of 0 ≦ x ≦ 1, and y may be a real number of 0 ≦ y ≦ 1. As a practical example, the chalcogenide particles may comprise one or more particles selected from Sn (S _y Se _1-y ), Sn ₂ (S _y Se _1-y ) _3, and Sn (S _y Se _1-y ) ₂ and Zn And a mixture of (S _y Se _1-y ) particles. At this time, in the chalcogenide particles, y is a real number of 0 ≦ y ≦ 1.

As a more practical example, the chalcogenide particles may include one or more particles selected from In ₂ Se ₃ , Ga ₂ S ₃ , ZnS, and SnS.

 In the ink according to an embodiment of the present invention, the chalcogenide particles may be nanoparticles in terms of low temperature reactivity with copper nanoparticles, and the average particle size of the chalcogenide nanoparticles may be 5 to 200 nm. At this time, the chalcogenide particles may have a uni-modal, bi-modal or more distribution.

In the ink according to one embodiment of the present invention, by the reaction of the copper nanoparticles and the chalcogenide particles, a single-phase multi-element chalcogenide compound is prepared at a low temperature heat treatment temperature of 550 ° C. or lower, and larger crystal grains In order to prepare a multi-element chalcogenide compound, the average size of the chalcogenide particles is preferably smaller than the average size of the copper nanoparticles.

As a practical example, at low temperature heat treatment temperature, in order to prepare a single-phase multi-phase chalcogenide compound having an average grain size of micrometer order, the average size of the chalcogenide particles is 1 / based on the average size of the copper nanoparticles. It is preferred to have a size of 100 to 1/10.

As a more practical example, the average size of the chalcogenide particles may be 1 to 20nm and the average size of the copper nanoparticles may be 10nm to 200nm.

In the ink according to an embodiment of the present invention, the chalcogenide particles may be amorphous chalcogenide particles, thereby reacting with the copper nanoparticles at a low temperature within a process allowable temperature, and thereby more quickly and uniformly multi-phase single phase. Chalcogen compounds can be prepared.

In the ink according to an embodiment of the present invention, the copper nanoparticles contained in the ink is capped with an acid and an amine prepared by heating and stirring a copper precursor solution containing a copper precursor, an acid and an amine, and then injecting a reducing agent ( capped copper nanoparticles.

Copper nanoparticles prepared by heating a copper precursor solution containing a copper precursor, an acid and an amine at the same time, and adding a reducing agent are capped with an acid and an amine. When copper nanoparticles are produced, oxide film formation on the surface of the particles is prevented. Irrespective of the storage state and storage time of the ink, generation of the particle surface oxide film can be prevented, and the degradation of the reactivity caused by the surface oxide film of the copper nanoparticles can be remarkably prevented.

In the production of copper nanoparticles, the copper precursor may be one or more selected from inorganic salts consisting of nitrates, sulfates, acetates, phosphates, silicates and hydrochlorides of copper.

In preparing the copper nanoparticles, the acid contained in the copper precursor solution may be saturated or unsaturated acid, and one or two or more selected from linear, branched, and cyclic carbon atoms of 6 to 30 may be selected. As a practical example, the acid contained in the copper precursor solution may be oleic acid, lysineoleic acid, stearic acid, hydroxystearic acid, linoleic acid, aminodecanoic acid, hydroxy decanoic acid, lauric acid, dekenoic acid, undecanoic acid, And one or more acids selected from palitoleic acid, hexyldecanoic acid, hydroxypalmitic acid, hydroxymyritic acid, hydroxydecanoic acid, palmitoleic acid and misrisoleic acid.

At this time, in the copper precursor solution, the molar ratio between the copper precursor and the acid may be 1 (copper precursor): 0.2 to 4 (acid). The molar ratio of acid to copper precursor is a ratio that prevents the formation of the surface oxide layer and is capable of producing copper nanoparticles in the shape of particles capped with acid and amine while achieving perfect capping. In other words, if the molar ratio of the acid to the precursor is less than 0.2, the capping may not be performed perfectly, and some copper which is not capped may be oxidized. If the molar ratio exceeds 4, all of the capping materials may not react and the capping materials may mutually The entanglement prevents recovery in the form of capped particles.

In preparing the copper nanoparticles, the amine contained in the copper precursor solution may serve as a solvent while simultaneously serving as a capping agent together with an acid. The amine as a capping agent and solvent may comprise saturated or unsaturated acids, and may be selected from one or two or more of straight, branched and cyclic having 6 to 30 carbon atoms. In one practical example, the amine contained in the copper precursor solution is one from hexyl amine, heptyl amine, octyl amine, dodecyl amine, 2-ethylhexyl amine, 1,3-dimethyl-n-butyl amine and 1-aminotordecane It may comprise more than one acid selected.

In this case, in the copper precursor solution, the molar ratio of the copper precursor and the amine may be 1 (copper precursor): 5 to 15 (amine). The molar ratio of the amine to the precursor serves as a solvent and a capping agent, and is a ratio capable of forming a capping film having a surface oxide film prevented with acid.

In the preparation of copper nanoparticles, the reducing agent is hydrazine, phenylhydrazine, tetrabutylammonium borohydride, tetramethylammonium borohydride, tetraethylammonium borohydride, sodium phosphate, sodium borohydride and ascrobic acid One or more selected from may include the selected material.

In preparing the copper nanoparticles, the copper precursor solution may be heated and stirred at a temperature of 100 to 240 ° C., preferably 140 to 240 ° C., and a reducing agent may be added while the copper precursor is heated (100 to 240 ° C.). have.

In preparing the copper nanoparticles, 80 to 200 parts by weight of a reducing agent may be added to 100 parts by weight of the copper precursor solution heated to a temperature of 100 to 240 ° C.

The copper precursor solution containing the copper precursor and the amine and the acid at the same time is heated to a temperature of 100 to 240 ℃, and then by adding a reducing agent, the copper capping particles capped with the acid and the amine can be prepared in nano size, uniform It is not only possible to manufacture spherical copper nanoparticles (capped copper nanoparticles), but also easy to process by adding amine and acid at a time and reacting them. Can be completely prevented, it is possible to produce a copper nanoparticles that do not have a surface oxide film at all.

Ink according to an embodiment of the present invention may further contain a solvent for forming a dispersion medium of copper nanoparticles and chalcogenide particles.

The solvent for forming the dispersion medium may be a solvent that is used in a conventional ink composition containing particulates and the coating process is carried out. For example, the solvent is a nonpolar solvent, a polyol solvent, an amine solvent, a phosphine solvent, an alcohol solvent. It may contain one or more solvents selected from solvents and polar solvents.

As a practical example, the polyol solvent may be selected from the group consisting of diethylene glycol, diethylene glycol ethyl ether, diethylene glycol buthyl ether, triethylene glycol, polyethyleneglycol poly (ethylene glycol) diacrylate, poly (ethylene glycol) dibenzonate, dipropylene glycol, poly (ethylene glycol) Dipropylene glycol, and glycerol. The solvent may be selected from one or more selected from the group consisting of dipropylene glycol and glycerol.

As a practical example, amine-based solvents include diethylamine, triethylamine, 1,3-propane diamine, 1,4-butane diamine, diamine, 1,5-pentane diamine, 1,6-hexane diamine, 1,7-heptane diamine, 1, Diethylene diamine, octane diamine, diethylene diamine, 8-octene diamine, diethylene triamine, toluene diamine, m-phenylenediamine, (diphenyl methane diamine), hexamethylene diamine, triethylene tetramine, tetraethylenepentamine, hexamethylene tetramine, ethanolamine, diethanolamine diethanolamine) and triethanolamine (triethanolamine). Can.

As a practical example, the phosphine solvent may include a solvent selected from one or two or more from trioctylphosphine and trioctylphosphineoxide.

As a practical example, the alcoholic solvent may be selected from one or more selected from methyl cellosolve, ethyl cellosolve, butyl cellosolve, and alcohols having 1 to 8 carbon atoms Solvent.

As a practical example, the apolar solvent may be selected from the group consisting of toluene, chloroform, chlorobenzene, dichlorobenzene, anisole, xylene, And may include one or more solvents selected from hydrocarbon-based solvents.

As a practical example, the polar solvent may be selected from the group consisting of formamide, diformamide, acetonitrile, tetrahydrofuran, dimethylsulfoxide, acetone, May include one or more solvents selected from the group consisting of terpineol,? -Terpineol, dihydro-terpineol and water.

The ink according to an embodiment of the present invention may further contain a dispersant and an organic binder.

The dispersant and the organic binder contain a particulate phase, and the dispersant and the organic binder used in the conventional ink composition in which the coating process is performed are satisfactory.

For example, the dispersant may be selected from the group consisting of fatty acid salts (soaps), alpha -sulfo fatty acid ester salts (MES), alkylbenzenesulfonic acid salts (ABS), linear (straight chain) alkylbenzenesulfonic acid salts (LAS) Low molecular weight anionic compounds including sulfuric acid ester salts (AES) and alkyl sulfuric acid triethanol; Low molecular weight non-ionic compounds including fatty acid ethanol amides, polyoxyethylene alkyl ethers (AE), polyoxyethylene alkyl phenyl ethers (APE), sorbitol and sorbitan; Low molecular weight cationic compounds including alkyltrimethylammonium salts, dialkyldimethylammonium chlorides and alkylpyridinium chlorides; Low molecular weight positively charged compounds including alkylcarboxybetaines, sulfobetaine, and lecithin; A polymeric water-based dispersant including a formalin condensate of a naphthalene sulfonate, a polystyrene sulfonate, a polyacrylate, a copolymer salt of a vinyl compound and a carboxylic acid monomer, carboxymethylcellulose, and polyvinyl alcohol; Polymeric non-aqueous dispersing agent comprising a polyacrylic acid partial alkyl ester and a polyalkylene polyamine; And a polymeric cationic dispersing agent comprising a polyethyleneimine and an aminoalkyl methacrylate copolymer.

As a non-limiting example, the dispersing agent may be a commercial product, and specific examples include EFKA4008, EFKA4009, EFKA4010, EFKA4015, EFKA4046, EFKA4047, EFKA4060, EFKA4080, EFKA7462, EFKA4020, EFKA4050, EFKA4055, EFKA4400, EFKA4401, EFKA4402, EFKA4403, DisperBYK101, DisperBYK102, DisperBYK106, DisperBYK108, DisperBYK111 (manufactured by EFKA ADDITIVES BV), TEXAPHOR-UV21 and TEXAPHOR-UV61 (produced by Cognis Japan K.K.), EFKA4300, EFKA4300, EFKA4340, EFKA6220, EFKA6225, EFKA6700, EFKA6780, EFKA6782, EFKA6782, , DisperBYK116, DisperBYK130, DisperBYK140, DisperBYK142, DisperBYK145, DisperBYK161, DisperBYK162, DisperBYK163, DisperBYK164, DisperBYK166, DisperBYK167, DisperBYK168, DisperBYK170, DisperBYK171, DisperBYK174, DisperBYK180, DisperBYK182, DisperBYK192, DisperBYK193, DisperBYK2000, DisperBYK2001, DisperBYK2020, DisperBYK2025, DisperBYK2050, DisperBYK2070 , DisperBYK2155, DisperBYK2164, BYK220S, BYK300, BYK306, BYK320, BYK322, BYK325, BYK330, BYK340, BYK350, BYK377, BYK378 , BYK380N, BYK410, BYK425, and BYK430 (manufactured by Big Chemical Japan K.K.), FTX-207S, FTX-212P, FTX-220P, FTX-220S, FTX-228P, FTX-710LL, FTX- ftergent) 212P, printer 220P, printer 222F, printer 228P, printer 245F, printer 245P, printer 250, printer 251, printer 710FM, printer 730FM, MEGAFACE F-477, Megapack 480SF, or Megapack F-482 (manufactured by DIC Corporation), manufactured by Nippon Kayaku Co., Ltd., ) Can be used.

For example, the organic binder may be selected from the group consisting of polyvinyl alcohol (PVA), polyvinyl butyral (PVB), polyvinyl pyrrolidone (PVP), polyvinylidene fluoride (PVDF), self- crosslinkable acrylic resin emulsion, hydroxyethyl cellulose HEC), carboxymethylcellulose (CMC), styrene butadiene rubber (SBR), copolymers of C1-10 alkyl (meth) acrylate and unsaturated carboxylic acid, nitrocellulose, gelatin, Polyvinyl butyral, thixoton, starch, polyether-polyol, polystyrene (PS-NH2) end-treated with amine groups, hydroxy cellulose, methyl cellulose, nitrocellulose, ethyl cellulose, ethyl A resin containing a carboxyl group, a phenolic resin, a mixture of ethylcellulose and a phenolic resin, an ester polymer, a methacrylic resin, In the methacrylate polymer, ethylenic copolymer having unsaturated groups, ethyl cellulose, an acrylate and an epoxy resin may comprise a material that is selected more than one or two.

In the ink according to an embodiment of the present invention, the photoactive layer to be prepared is CIGS (Cu-In-Ga-Se or Cu-In-Ga-S), CIGSS (Cu-In-Ga-Se-S), In the case of CZTS (Cu-Zn-Sn-Se or Cu-Zn-Sn-S) or CZTSS (Cu-Zn-Sn-Se-S), one or more elements selected from group 12 to 14 (chalcogen compounds Element contained in Groups 12 to 14): copper nanoparticles and chalcogenide particles may be contained so that the molar ratio of copper is 1: 0.7 to 1.2.

An ink according to an embodiment of the present invention may contain 200 to 900 parts by weight of a solvent based on 100 parts by weight of a particulate including copper nanoparticles and chalcogenide particles.

In the ink according to an embodiment of the present invention, when the ink further contains a dispersant and an organic binder, 0.5 to 10 parts by weight of the dispersant and 0.5 to 10 parts by weight of particulates including the copper nanoparticles and the chalcogenide particles It can contain 10 parts by weight of the organic binder.

Contents of the solvent, optionally a dispersant, and an organic binder based on the particulate phase including the copper nanoparticles and the chalcogenide particles according to the above-described embodiments may be used to maintain the shape of the film while the coating process is performed smoothly. Adhesion with the substrate to be applied, the content that can prevent the degradation of the film quality by the organic material that is decomposed and removed during drying and heat treatment.

Hereinafter, a method for producing the solar cell photoactive layer using the ink described above will be described in detail.

Method for producing a photovoltaic cell active layer according to the present invention comprises a) a coating film is formed by applying the above-described ink containing a) copper nanoparticles; and chalcogenide particles of one or more elements selected from group 12 to 14 Doing; And b) subjecting the coating film to heat treatment to produce a polyvalent chalcogen compound film of copper and one or more elements selected from group 12 to group 14.

Since the conventional compound semiconductor (CIG (S, Se)) or CZT (S, Se) -based photoactive layer is a multi-component compound, the manufacturing process is very difficult. Electrodeposition is one of the physical thin film manufacturing methods such as evaporation, sputtering and selenization. Chemical thin film manufacturing methods include electrodeposition. In each method, various manufacturing processes Method is being used.

However, the production method of the present invention does not use gaseous organometallic compounds or expensive vacuum equipment which are expensive and difficult to handle, and a highly complicated process such as multilayer deposition is unnecessary. In other words, the manufacturing method of the present invention is a high-quality multi-factor chalcogenide compound (photoactive layer) by applying an ink containing copper nanoparticles and chalcogenide particles and heat-treating the coating film very simple, safe and easy process can do.

In addition, the manufacturing method of the present invention, by producing a photoactive layer using the above-described ink, the polyphase of a single phase at a temperature within a process tolerance temperature of 550 ℃ or less in which the mechanical strength of an organic substrate commonly used as a solar cell insulator substrate is maintained. A photoactive layer made of a chalcogenide compound may be prepared, and has an excellent uniformity, a fine microstructure, and an advantage of manufacturing a photoactive layer made of coarse grains having a micrometer order size.

In the method of manufacturing the photoactive layer of the solar cell according to an embodiment of the present invention, the substrate to which the ink is applied may be a non-conductive substrate commonly used in the field of solar cells, And may include a laminated substrate. Examples of the non-conductive substrate include a glass substrate, a soda-lime glass substrate, a ceramic substrate, and a semiconductor substrate. As an example of the back electrode formed on the non-conductive substrate, a molybdenum (Mo) layer can be mentioned.

In the method of manufacturing the photoactive layer of the solar cell according to an embodiment of the present invention, the application of the ink may be carried out by a method such as spin coating, bar coating, dip coating, drop casting, ink-jet printing, micro- printing, imprinting, gravure printing, gravure-offset printing, flexography printing and screen printing in one or more selected ways. .

In the method for manufacturing the solar cell photoactive layer according to an embodiment of the present invention, a step of drying the coating film may be further performed after the steps a) and b). The drying step is for volatilizing and removing the liquid phase contained in the coating film and can be used as long as it is a drying method usually used in the field of forming a film by application of ink. As a non-limiting example, drying of the coating film can be carried out at 60 to 90 ° C in air.

In the method of manufacturing the solar cell photoactive layer according to an embodiment of the present invention, the heat treatment of the coating film formed by applying ink on the substrate may be performed at 400 to 550 ° C, preferably 500 to 530 ° C.

In the method of manufacturing the solar cell photoactive layer according to an embodiment of the present invention, densification of the film, crystal growth, and phase transition to a single polychalcogen compound are performed by heat treatment of the applied coating film. That is, the phase transformation of the desired polychalcogen compound into a single phase is carried out by the reaction between the chalcogen compound containing the elements constituting the photoactive layer to be produced excluding copper and copper by the heat treatment of the coating film.

As described above, the pure polyphase chalcogenide of pure single phase is formed by the phase transition, and the polycrystalline chalcogenide having an average grain size of micrometer order and substantially 1 to 5 μm even at a heat treatment temperature of 550 ° C. or lower is obtained. Can be prepared.

In the manufacturing method according to the present invention, the heat treatment of the coating film can be performed in a chalcogen atmosphere. The chalcogen atmosphere includes an atmosphere in which sulfur (S), selenium (Se), or a mixed gas thereof exists.

In detail, the heat treatment of the coating film can be performed by supplying a chalcogen-containing gas or by heat-treating the chalcogen powder together with the coating film and using the chalcogen powder as a source of chalcogen gas.

More specifically, the heat treatment of the coating film, the chalcogen atmosphere includes an atmosphere in which sulfur (S), selenium (Se) or a mixture thereof is present, and the chalcogen gas atmosphere is a chalcogen, such as H ₂ S or H ₂ Se. Supplying a gas containing elements (S, Se), or supplying after chalcogen element (S, Se) is volatilized, or the chalcogen powder by heat-treating the chalcogen powder, which is a powder of chalcogen element, with a coating film It can be formed using as a source of chalcogen gas.

As a practical example, when supplying chalcogen gas, a chalcogen-containing gas containing H ₂ S, H ₂ Se, chalcogen element (S, Se) vapor or a mixed gas thereof is supplied at a flow rate of 5 to 300 sccm .

As a practical example, in the case where the chalcogen powder itself containing the S powder, the Se powder, or the mixed powder thereof is vaporized to form a chalcogen atmosphere in the chamber in which the heat treatment of the coating film is performed, And may be different from each other.

Specifically, when chalcogen powder is used as a chalcogen gas source, the chalcogen powder can be heated to 80 to 250 캜.

When the chalcogen powder is used as a source of kelogen gas, the chalcogen powder in the heat treatment apparatus can be placed in a region different from the region where the coating film is located. At this time, the heat treatment can be performed using an apparatus equipped with a heating element and a controller so that two or more uniform zones can be independently formed in a single heat treatment space capable of flowing the fluid, The heating temperature of the chalcogen powder can be controlled by controlling the position of the chalcogen powder in the heat treatment apparatus.

The heat treatment of the coating film may be carried out at any pressure, but in a non-limiting example, the heat treatment may be performed at a vacuum or an atmospheric pressure.

In the method of manufacturing a photovoltaic active layer of a solar cell according to an embodiment of the present invention, the plural chalcogenide is CuIn _k Ga _1-k Se _l S _1-l (0 ≦ _k ≦ ₁ real, 0 ≦ _l ≦ 1 Real number) and Cu ₂ Zn _m Sn _2-m (Se _n S _1-n ) ₄ (real number 0 ≦ _m ≦ 2, real number 0 ≦ _n ≦ ₁ ).

For example, Cu nanoparticles; and chalcogens of (In _x Ga _1-x ) ₂ (Se _y S _1-y ) ₃ (where x is a real number of 0 ≦ x ≦ 1 and y is a real number of 0 ≦ y ≦ 1). Using a ink containing compound particles, to prepare a multi-phase chalcogenide compound of CuIn _k Ga _1-k Se _l S _1-l work (real number 0 ≦ _k ≦ ₁ , real number 0 ≦ _l ≦ ₁ ) can do. In this case, as described above, the molar ratio of In and Ga (In and Ga of chalcogenide particles) to Cu (Cu of copper particles) contained in the ink may be 1: 0.7 to 1.2.

As an example, a single-phase multi-phase chalcogenide of CuInSe ₂ may be prepared using an ink containing Cu nanoparticles and In ₂ Se ₃ chalcogenide particles.

For example, CuIn _k Ga _1-k Se _l S _1-l day (0 ≦ _k ≦) using an ink containing Cu nanoparticles, In ₂ Se ₃ chalcogenide particles, and Ga ₂ S ₃ chalcogenide particles It is possible to produce a single-phase, multi-element chalcogen compound having a real number of 1 and a real number of 0 ≦ l ≦ 1). In this case, the molar ratio of In and Ga (In and Ga of the chalcogenide particles): Cu (Cu of copper particles) contained in the ink may be 1: 0.7 to 1.2, and the molar ratio of In: Ga is a multi-purpose knife to be prepared. It may be based on the molar ratio (k: 1-k) of In: Ga of the cogen compound.

For example, Cu nanoparticles; ZnS _y Se _1-y chalcogenide particles (y is 0 ≤ y ≤ 1 real) and SnS _y Se _1-y chalcogenide particles (y is 0 ≤ y ≤ 1 ) Is used to prepare a single-phase polychalcogen compound of Cu ₂ Zn _m Sn _2-m (Se _n S _1-n ) ₄ (real number 0 ≦ _m ≦ 2, real number 0 ≦ _n ≦ ₁ ). It can manufacture. At this time, the molar ratio of Zn and Sn (Zn and Sn of chalcogen compound particles): Cu (Cu of copper particles) contained in the ink may be 1: 0.7 to 1.2, and the molar ratio of Zn: The molar ratio of Zn: Sn of the zeolite compound (m: 2-m) can be used.

The present invention includes a photoactive layer produced by the above-described manufacturing method.

The present invention includes a solar cell provided with a photoactive layer manufactured by the above-described manufacturing method.

A solar cell according to an embodiment of the present invention includes the above-described photoactive layer formed on a substrate (substrate on which a lower electrode is formed); A buffer layer formed on the photoactive layer; A window layer formed on the buffer layer; And a grid electrode formed on the window layer.

When the pn junction between the photoactive layer of the first conductivity type semiconductor (for example, p-type in the case of CIGS) and the window layer of the second conductivity type semiconductor (for example, n-type in the case of ZnO thin film) A buffer layer used in a conventional compound semiconductor-based solar cell may be used in order to alleviate the lattice constant and the band gap energy difference of the buffer layer. As an example, the buffer layer may be a CdS thin film.

The window layer is a layer having a semiconductor characteristic complementary to the photoactive layer and can be used as a window layer used in a conventional compound semiconductor-based solar cell capable of forming a p-n junction with the photoactive layer. For example, the window layer may be a ZnO thin film.

The grid electrode is for collecting current on the surface of the solar cell and may include a finger electrode and a bus bar electrode, and can be used as a front electrode structure and a material used in a conventional compound semiconductor-based solar cell. In one example, the grid electrode may have a fulcrum structure and may be made of Al or a Ni / Al material.

The solar cell according to an embodiment of the present invention may further include an antireflection film formed on the grid electrode, and may be used as an antireflection film used in a conventional compound semiconductor based solar cell. In one example, the antireflection film may be a silicon oxide film.

Hereinafter, the present invention will be described in detail based on practical examples. It is to be understood that the same is by way of example only and is not to be construed as limiting the scope of the present invention. It will be apparent to those skilled in the art that various modifications and variations can be made from this disclosure.

(Production Example 1)

In order to synthesize Cu nanoparticles, 73.63 g of octylamine and 25.1 g of oleic acid were mixed in a flask, and 10.38 g of Cu acetate was added to prepare a copper precursor solution. . After making an inert atmosphere using nitrogen gas, the copper precursor solution was heated to 150 ° C., and 87.4 g of phenylhydrazine was added to induce a reduction reaction of copper ions to synthesize copper nanoparticles. Thereafter, the synthesized copper nanoparticles were separated by centrifugation and washed with toluene.

In order to synthesize chalcogenide particles, 80 ml of octylamine was added to the flask and the flask temperature was fixed at 60 ° C. Then, the flask _{In (acac) 3 (acac =} acetylacetonate, pentane-2,4-dione) 8 mmol and followed by the addition of 12 mmol Se powder, the temperature was increased to 290 ℃ maintained at 290 ℃ for 1 hour to In ₂ Se ₃ particles were synthesized. Thereafter, the synthesized chalcogen compound particles were separated by centrifugation and washed with toluene.

The prepared Cu nanoparticles and In ₂ Se ₃ particles were added to toluene so that the molar ratio of Cu: In is 1: 1. At this time, the amount of toluene was 400 parts by weight based on 100 parts by weight of the combined particulate particles of Cu nanoparticles and In ₂ Se ₃ particles. After the particulate phase was added to toluene, ball milling was performed for 60 minutes at 20 Hz for homogeneous mixing to prepare an ink.

After the Mo electrode is deposited soda and a bar coating ink prepared in the lime glass substrate, and dried at 80 ℃, heating the Se powder in 230 ℃ and the CuInSe ₂ thin film by heating the glass substrate on which the ink is applied at 530 ℃ temperature Photoactive layer was prepared. The pressure in the heat treatment chamber was 10 ^-5 torr.

(Production Example 2)

In order to synthesize Cu nanoparticles, 73.63 g of octylamine and 25.1 g of oleic acid were mixed in a flask, and 10.38 g of Cu acetate was added to prepare a copper precursor solution. . After making an inert atmosphere using nitrogen gas, the copper precursor solution was heated to 150 ° C., and 87.4 g of phenylhydrazine was added to induce a reduction reaction of copper ions to synthesize copper nanoparticles. Thereafter, the synthesized copper nanoparticles were separated by centrifugation and washed with toluene.

To synthesize In ₂ Se ₃ chalcogen compound particles, 80 ml of octylamine was added to the flask, and the flask temperature was fixed at 60 ° C. Then, the flask _{In (acac) 3 (acac =} acetylacetonate, pentane-2,4-dione) 8 mmol and followed by the addition of 12 mmol Se powder, the temperature was increased to 290 ℃ maintained at 290 ℃ for 1 hour to In ₂ Se ₃ particles were synthesized. Thereafter, the synthesized chalcogen compound particles were separated by centrifugation and washed with toluene.

The synthesized copper nanoparticles, In ₂ Se ₃ particles and Ga ₂ S ₃ (Aldrich) were mixed together with toluene to prepare an ink for the photoactive layer. The materials were added to toluene such that the molar ratio of Cu: (In + Ga) was 1: 1 and the molar ratio of In: Ga was 7: 3. At this time, the amount of toluene was 400 parts by weight based on 100 parts by weight of the mixed material. After the particulate phase was added to toluene, ball milling was performed for 60 minutes at 20 Hz for homogeneous mixing to prepare an ink.

After the Mo electrode is deposited soda and a bar coating ink prepared in the lime glass substrate, and dried at 80 ℃, heating the Se powder in 230 ℃ and heat-treating the glass substrate, the ink is applied at 530 ℃ temperature Cu (In _0.7 Ga _0.3 ) (S, Se) ₂ thin film was prepared. The pressure in the heat treatment chamber was 10 ^-5 torr.

(Production Example 3)

In order to synthesize Cu nanoparticles, 73.63 g of octylamine and 25.1 g of oleic acid were mixed in a flask, and 10.38 g of Cu acetate was added to prepare a copper precursor solution. . After making an inert atmosphere using nitrogen gas, the copper precursor solution was heated to 150 ° C., and 87.4 g of phenylhydrazine was added to induce a reduction reaction of copper ions to synthesize copper nanoparticles. Thereafter, the synthesized copper nanoparticles were separated by centrifugation and washed with toluene.

To prepare the ink for the photoactive layer, the synthesized copper nanoparticles, ZnS (Aldrich) and SnS (Aldrich), were mixed together with toluene. The materials were added to toluene such that the molar ratio of Cu: Zn: Sn was 2: 1: 1. At this time, the amount of toluene was 400 parts by weight based on 100 parts by weight of the mixed material. After the particulate phase was added to toluene, ink was prepared by performing ball milling for 60 minutes at 20 Hz for homogeneous mixing.

The ink prepared on the soda lime glass substrate on which the Mo electrode was deposited was bar coated and dried at 80 DEG C and then the glass substrate coated with ink was heat-treated at a temperature of 530 DEG C while supplying H ₂ S gas at a flow rate of 100 SCCM Cu ₂ ZnSnS ₄ thin films.

(Production Example 4)

In order to synthesize Cu nanoparticles, 73.63 g of octylamine and 25.1 g of oleic acid were mixed in a flask, and 10.38 g of Cu acetate was added to prepare a copper precursor solution. . After making an inert atmosphere using nitrogen gas, the copper precursor solution was heated to 150 ° C., and 87.4 g of phenylhydrazine was added to induce a reduction reaction of copper ions to synthesize copper nanoparticles. Thereafter, the synthesized copper nanoparticles were separated by centrifugation and washed with toluene.

Copper nanoparticles synthesized to prepare inks for photoactive layers, ZnS (Aldrich), SnS (Aldrich) was mixed with toluene. The materials were added to toluene such that the molar ratio of Cu: Zn: Sn was 2: 1: 1. At this time, the amount of toluene was 400 parts by weight based on 100 parts by weight of the mixed material. After the particulate phase was added to toluene, ball milling was performed for 60 minutes at 20 Hz for homogeneous mixing to prepare an ink.

After coating the ink prepared on the soda-lime glass substrate on which the Mo electrode was deposited, drying at 80 ° C., heating the Se powder to 230 ° C., and heating the ink-coated glass substrate at a temperature of 530 ° C. to obtain Cu ₂ ZnSn ( S, Se) ₂ thin film was prepared a photoactive layer. The pressure in the heat treatment chamber was 10 ^-5 torr.

(Comparative Example)

10 ml of oleylamine was added to each of the first and second flasks, and the temperature was fixed at 60 ° C. 0.32 ml of oleic acid was added to the first flask, and 2 mmol of CuCl _{2 and} 2 mmol of InCl ₃ were added thereto. 4 mmol of Se powder was added to the second flask, and the first flask was warmed to 130 ° C. and the second flask to 240 ° C. to dissolve for one hour. Then, after changing the temperature of the first flask to 100 ℃, the second flask to 200 ℃, when the temperature of the second flask is 200 ℃ instant injection of the solution of the first flask into the second flask, instant injection and At the same time, the temperature of the second flask was changed to 240 ° C and maintained for 1 hour to synthesize CuInSe ₂ particles. Thereafter, the synthesized CuInSe ₂ particles were separated by centrifugation and washed with toluene.

Synthesized CuInSe ₂ particles and toluene were mixed to prepare an ink containing 20% by weight of CuInSe ₂ particles. At this time, ball milling was carried out at 20 Hz for 60 minutes for homogeneous mixing of the ink. After the Mo electrode is deposited soda and a bar coating ink prepared in the lime glass substrate, and dried at 80 ℃, heating the Se powder in 230 ℃ and the CuInSe ₂ thin film by heating the glass substrate on which the ink is applied at 530 ℃ temperature Photoactive layer was prepared. The pressure in the heat treatment chamber was 10 ^-5 torr.

Table 1 summarizes the results of observing the microstructure of the photoactive layers prepared in Preparation Examples 1 to 4 and Comparative Examples using a scanning electron microscope.

(Table 1)

As can be seen from Table 1, the photoactive layer prepared from the ink composition comprising copper nanoparticles has a dense microstructure, while the photoactive layer prepared from the ink composition comprising single-phase CuInSe ₂ nanoparticles has a porous structure. You can see that.

1 is a view showing an X-ray diffraction pattern of the Cu nanoparticles synthesized in Preparation Example 1, Figure 2 is a view showing a scanning electron micrograph of the Cu nanoparticles synthesized in Preparation Example 1. 1 and 2, it can be seen that spherical copper nanoparticles having an average particle size of 40 nm and 100 nm were synthesized bimodally. In addition, XPS analysis of the Cu nanoparticles prepared in Preparation Example 1 confirmed that no oxide film was formed.

3 is a view showing a scanning electron micrograph of In ₂ Se ₃ synthesized in Preparation Example 1. As can be seen from FIG. 3, it can be seen that chalcogen compound particles of In ₂ Se ₃ were synthesized, and that chalcogen compound particles having an average particle size of 13 nm were synthesized.

As a result of X-ray diffraction analysis of the synthesized In ₂ Se ₃ particles, it was confirmed that amorphous particles were produced. As a result of ICP composition analysis, it was confirmed that particles of In ₂ Se ₃ composition were produced.

4 is a view showing an X-ray diffraction pattern of the photoactive layer of CuInSe ₂ thin film prepared in Preparation Example 1, Figure 5 is a view showing a scanning electron micrograph of the photoactive layer prepared in Preparation Example 1.

As can be seen in Figure 4, it can be seen that a thin film made of CuInSe ₂ is produced, as can be seen in Figure 5, it can be seen that a thin film having a dense microstructure significantly improved at a temperature of 530 ℃, the average grain It can be seen that a photoactive layer of large grains having a size of 1 μm or more is prepared. In addition, it can be seen that a photoactive layer thin film having a pure single phase without a secondary phase was prepared through a phase transition process into a single phase of CuInSe ₂ together with densification behavior.

6 is a view showing the X- ray diffraction pattern of the CuInSe ₂ particles prepared in Comparative Example, Figure 7 is a view showing a scanning electron micrograph of the CuInSe ₂ particles prepared in Comparative Example. 6 and 7, it can be seen that in Comparative Examples, crystalline CuInSe ₂ particles having an average particle size of about 15 nm were prepared.

FIG. 8 is a cross-sectional scanning electron micrograph of a photoactive layer prepared using an ink containing CuInSe ₂ particles prepared in Comparative Example, and as shown in FIG. 8, the shape of CuInSe ₂ nanoparticles contained in the ink as it is. It can be seen that the photoactive layer thin film of the porous structure is prepared, and the densification and particle growth are hardly achieved.

While the present invention has been described in detail with reference to the preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. All of which fall within the scope of the present invention.

Claims (10)

Ink containing copper nanoparticles; and chalcogenide particles of one or more elements selected from group 12 to 14 a) forming a coating film by applying an ink containing copper nanoparticles; and chalcogenide particles of one or more elements selected from Groups 12 to 14 to a substrate; And
b) heat-treating the coating film to produce a poly-chalcogen compound film of one or more elements selected from copper and group 12 to 14;
≪ / RTI > The method of claim 2,
The Group 12 includes zinc (Zn), the Group 13 is at least one selected from indium and gallium, the Group 14 comprises Sn, the chalcogen element is at least one selected from sulfur and selenium Manufacturing method. The method of claim 2,
The chalcogenide particles are (In _x Ga _1-x ) ₄ (S _y Se _1-y ) ₃ , (In _x Ga _1-x ) (S _y Se _1-y ), (In _x Ga _1-x ) ₆ (S _y Se _1-y ) ₇ , (In _x Ga _1-x ) ₉ (S _y Se _1-y ) ₁₁ , (In _x Ga _1-x ) ₂ (S _y Se _1-y ) ₃ and ( One or more selected particles from In _x Ga _1-x ) ₅ (S _y Se _1-y ) ₇ (real numbers 0 ≤ x ≤ 1, y is a real number 0 ≤ y ≤ 1); or One or more particles selected from S _y Se _1-y , Sn ₂ (S _y Se _1-y ) _3, and Sn (S _y Se _1-y ) ₂ (y is a real number where 0 ≦ y ≦ 1) and Zn (S _y Se _1-y ) A method of manufacturing a photoactive layer comprising particles (y is a real number of 0 ≦ y ≦ 1). The method of claim 2,
The method of manufacturing a solar cell photoactive layer in which the molar ratio of one or two or more selected elements: copper in Groups 12 to 14 contained in the ink is 1: 0.7 to 1.2. The method of claim 2,
Wherein the heat treatment is performed at 400 to 550 占 폚. The method according to claim 6,
Wherein the heat treatment is performed in a chalcogen atmosphere. The method of claim 2,
The copper nanoparticles are copper nanoparticles prepared by heating and stirring a copper precursor solution containing a copper precursor, an acid and an amine, and then injecting a reducing agent. The method of claim 2,
The method of manufacturing a solar cell photoactive layer in which a multi-phase chalcogenide compound of a single phase is formed by the heat treatment. The solar cell photoactive layer manufactured by the manufacturing method of any one of claims 2 to 9.

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