KR20160131454A - Method for preparation of graphene by using dye - Google Patents
Method for preparation of graphene by using dye Download PDFInfo
- Publication number
- KR20160131454A KR20160131454A KR1020150063875A KR20150063875A KR20160131454A KR 20160131454 A KR20160131454 A KR 20160131454A KR 1020150063875 A KR1020150063875 A KR 1020150063875A KR 20150063875 A KR20150063875 A KR 20150063875A KR 20160131454 A KR20160131454 A KR 20160131454A
- Authority
- KR
- South Korea
- Prior art keywords
- graphene
- feed solution
- dye
- graphite
- high pressure
- Prior art date
Links
- 0 *S(c(cc12)ccc1C(N=NC(c1c3cccc1)=CC[C@]3N=Nc1cc(c(S(*)(=O)=O)ccc3)c3c(S(*)(=O)=O)c1)=CC[C@@]2N=Nc(c(O)c(ccc(N)c1)c1c1)c1S(OC1CC1)(=O)=O)(=O)=O Chemical compound *S(c(cc12)ccc1C(N=NC(c1c3cccc1)=CC[C@]3N=Nc1cc(c(S(*)(=O)=O)ccc3)c3c(S(*)(=O)=O)c1)=CC[C@@]2N=Nc(c(O)c(ccc(N)c1)c1c1)c1S(OC1CC1)(=O)=O)(=O)=O 0.000 description 1
Images
Classifications
-
- C01B31/0469—
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B2204/00—Structure or properties of graphene
- C01B2204/04—Specific amount of layers or specific thickness
Abstract
The present invention relates to a method of producing graphene using a dye, and is characterized in that graphene which is hydrophobic and a dye which mediates a solvent of a hydrophilic feed solution are used to increase graphene peeling efficiency and dispersion stability at high pressure homogenization have.
Description
The present invention relates to a method for producing graphene using a dye.
Graphene is a semimetallic material with a thickness corresponding to the carbon atomic layer, with the carbon atoms forming a hexagonally connected arrangement in two dimensions on the sp2 bond. Recently, evaluation of the characteristics of a graphene sheet having a carbon atom layer of one layer has revealed that the electron mobility is about 50,000 cm 2 / Vs or more and can exhibit very excellent electric conductivity.
Graphene also has structural, chemical stability and excellent thermal conductivity characteristics. In addition, it is easy to process one- or two-dimensional nanopatterns composed of carbon, which is a relatively light element. Graphene is expected to replace silicon-based semiconductor technology and transparent electrodes due to its electrical, structural, chemical, and economic properties, and it is expected to be applicable to flexible electronic devices due to its excellent mechanical properties.
Due to the many advantages and excellent properties of such graphenes, various methods have been proposed or studied to more effectively produce graphene from carbon-based materials such as graphite. Particularly, there have been various studies on a method for easily producing a graphene sheet or flake having a thinner thickness and a larger area so that excellent characteristics of graphene can be more dramatically developed. Such conventional methods of producing graphene include the following.
First, a method of peeling a graphene sheet from graphite by a physical method such as using a tape is known. However, this method is not suitable for mass production methods, and the peeling yield is also very low.
There is known a method for obtaining graphene or an oxide thereof which is peeled off from an intercalation compound in which an acid, a base, a metal or the like is interposed between carbon layers of graphite, or by peeling by a chemical method such as oxidizing graphite.
However, in the former method, a large number of defects may be generated on the finally produced graphene in the process of oxidizing the graphite to proceed the exfoliation and reducing the graphene oxide obtained therefrom to obtain graphene again. This may adversely affect the properties of the final produced graphene. In addition, the latter method requires additional processes such as using and treating an intercalation compound, which may complicate the overall process, resulting in a low yield and a low cost. Further, in this method, it is not easy to obtain a large-area graphene sheet or flake.
Recently, a method of producing graphene by separating carbon layers contained in graphite by ultrasonic irradiation or a milling method using a ball mill or the like has been applied most recently in the state where graphite or the like is dispersed in a liquid state. However, these methods have also been problematic in that it is difficult to obtain graphene having a sufficiently thin thickness and a large area, a large number of defects are formed on the graphene in the peeling process, or the yield of peeling is insufficient.
As a result, there is a continuing need for a manufacturing method capable of easily producing a graphene sheet or flake having a thinner thickness and a larger area with higher yield.
The present invention is to provide a method for producing graphene capable of producing graphene with high efficiency using high pressure homogenization and a dye.
In order to solve the above problems, the present invention provides a feed solution containing graphite, comprising an inlet, an outlet, and a high-pressure homogenizer including a microchannel having a micrometer scale diameter and connecting between the inlet and outlet, in the graphene production method comprising the step of passing the feed solution comprises a molecule within anthraquinone, triphenylmethane, phthalocyanine or azobenzene structure molecules, and -SO 2 O -, which comprises a dye containing a substituent, yes A method for manufacturing a pin is provided.
The term "graphite" used in the present invention refers to a material which is also called graphite or talc and belongs to a hexagonal system having a crystal structure such as quartz, and is a material having a black color and metallic luster. The graphite has a plate-like structure. A single layer of graphite is called "graphene" to be produced in the present invention, and thus graphite becomes the main raw material for the production of graphene.
In order to peel off graphene from the graphite, it is necessary to apply energy to overcome the pi-pi interaction between the stacked graphenes. In the present invention, the high-pressure homogenization method is used as described later. The high-pressure homogenization method can apply a strong shear force to the graphite so that the graphene peeling efficiency is excellent. However, since the produced graphene coagulates, it is required to use a dispersant capable of dispersing the graphene peeled off.
The dispersant serves to maintain the dispersed state of the hydrophobic graphite or graphene and the solvent of the hydrophilic feed solution, and is also referred to as surfactant or release aid in another term. Particularly, the present invention is characterized in that a dye is used in order to effectively remove graphene, and the peeling efficiency is remarkably increased as compared with existing dispersants.
Hereinafter, the present invention will be described in detail.
dyes
In the present invention, a dye is used as a dispersing agent used for stripping graphite.
In general, SC (sodium cholate), sodium dodecyl benzene sulfonate (SDBS), or PVP (polyvinylpyrrolidone) are known as dispersants used for graphene peeling. However, since the dispersant does not have a strong covalent bond with the π-domain of graphene but a weak van der Waals interaction and exists in a dynamic equilibrium state, There is a problem that a large amount is required.
In the case of polyaromatic oxide (PAO), it consists of a hydrophobic group (alkyl chain, phenyl group, pyrene group, etc.) and a hydrophilic group that can bond to the basal plane of graphene by π-π interaction or Van der Waals. These PAOs share an electron of π-orbital through non-covalent bonds and can provide efficient steric repulsion even if only a small amount is added because hydrophilic moieties can provide sufficient steric repulsion. However, because of the use of mixed acid to make PAO, It is not only environmentally friendly but also economically difficult.
Accordingly, in the present invention, a dye having a structure similar to that of PAO but having a molecular weight smaller than that of PAO is applied as an auxiliary agent for peeling and dispersing graphite. Since the dye itself has a hydrophilic moiety in the π-domain and its surroundings, even though it is not prepared using a mixed acid such as PAO, the aromatic part has a π-π interaction with graphene and bonds well with graphene. Negative charge of the functional group suppresses the re-agglomeration of the exfoliated graphene to obtain thinly separated graphene and maintain dispersibility in solution.
Particularly, the dye used in the present invention is characterized by containing an anthraquinone, triphenylmethane, azobenzene or phthalocyanine structure in the molecule and containing -SO 2 O - substituent.
Intramolecular anthraquinone, triphenylmethane, azobenzene or the phthalocyanine structure of the dyes to serve π- Yes domain can be combined with the graphene by a pin and a π-π interaction, -SO 2 O - substituent is hydrophilic, so the structure It is possible to suppress the re-aggregation of graphene. Therefore, the dye can mediate the hydrophilic graphene and the hydrophilic feed solution to enhance the graphene peeling efficiency and the dispersion stability. The -SO 2 O - substituent may be in the form of a salt with Na + and the like.
Representative examples of dyes comprising the anthraquinone structure are:
Representative examples of dyes comprising the triphenylmethane structure are as follows:
Representative examples of dyes comprising the above azobenzene structure are as follows:
Representative examples of dyes containing the phthalocyanine structure are as follows:
Preferably, representative examples of the dye usable in the present invention are at least one of the compounds represented by the following formulas (1) to (3)
[Chemical Formula 1]
(2)
(3)
The dyes can be purchased and used commercially.
Feed solution
The term " feed solution " used in the present invention means a solution containing the graphite and the dye, which is introduced into a high-pressure homogenizer to be described later.
The concentration of the graphite in the feed solution is preferably 0.5 to 5 wt%. If the amount is less than 0.5% by weight, the concentration is too low to deteriorate the graphene peeling efficiency. If the amount is more than 5% by weight, the concentration may be excessively high, thereby blocking the flow path of the high-pressure homogenizer.
The concentration of the dye in the feed solution is preferably 0.1 mg / mL to 2 mg / mL. When the concentration is less than 0.1 mg / mL, the concentration of the dye is too low to degrade the graphene separation efficiency and dispersion effect. When the concentration exceeds 2 mg / mL, the dye may be too much to inhibit the expression of graphene.
Examples of the solvent for the feed solution include water, N-methyl-2-pyrrolidone, acetone, N, N-dimethylformamide, DMSO, CHP, N-dodecyl- pyrrolidone, benzyl benzoate, N-octyl-pyrrolidone, dimethyl-imidazolidinone, cyclohexanone, dimethylacetamide, NMF, bromobenzene, chloroform, Butanol, 2-ethoxyethanol, 2-butoxyethanol, 2-methoxypropanol, tetrahydrofuran (THF), ethylene glycol, pyridine, N-vinylpyrrolidone At least one selected from the group consisting of water, methyl ethyl ketone (butanone), alpha-terpineol, formic acid, ethyl acetate and acrylonitrile may be used, and water may be preferably used.
High pressure Homogenization
Homogenizing the feed solution at high pressure to peel the graphene from the graphite in the feed solution.
The term 'high pressure homogenization' means applying a high pressure to a micro-channel having a micrometer scale diameter to apply a strong shear force to the material passing through it. Typically, high pressure homogenization is performed using a high pressure homogenizer including an inlet, an outlet, and a microchannel connecting between the inlet and outlet and having a micrometer scale diameter.
As described above, since the hydrophilic graphene and the solvent of the hydrophilic feed solution are mediated by the dye in the feed solution, the graphene peeling effect by high pressure homogenization is excellent and the dispersion stability of the graphene peeled is excellent .
It is preferable that the fine flow path has a diameter of 10 to 800 탆. In addition, it is preferable that the feed solution flows into the inlet portion of the high pressure homogenizer through the micro flow path under a pressure of 100 to 3000 bar.
Further, the feed solution that has passed through the microchannel can be reintroduced into the inlet of the high-pressure homogenizer, so that the graphene can be further peeled off.
The recycling may be carried out two to ten times. The reintroduction process can be carried out repeatedly using the high-pressure homogenizer used or using a plurality of high-pressure homogenizers. In addition, the re-inputting process may be performed separately or sequentially.
On the other hand, a step of recovering and drying graphene from the graphene dispersion recovered in the outlet may be further included. The recovering step may be carried out by centrifugation, vacuum filtration or pressure filtration. The drying step may be performed by vacuum drying at a temperature of about 30 to 200 ° C.
The graphene thus prepared may be redispersed in various solvents and used for various purposes. The graphene can be applied to a conventional paste such as a conductive paste composition, a conductive ink composition, a composition for forming a heat dissipation substrate, an electroconductive composite, an EMI chassis composite, a conductive material for a battery, or a slurry.
The present invention is characterized in that dye is used to increase graphene peeling efficiency and dispersion stability during high pressure homogenization through a solvent of hydrophobic graphene and a hydrophilic feed solution.
Figure 1 shows an SEM image of the graphene dispersion prepared in one embodiment of the present invention. Figures 1 (a), 1 (c) and 1 (e) are magnifications of 20,000 magnifications, and Figures 1 (b), 1 (d) and 1 (f) are magnifications of 5,000 magnifications. 1 (a) and 1 (b) illustrate the results of Example 1, FIGS. 1 (c) and 1 (d) Image.
2 is a TEM image of the graphene dispersion prepared in Example 2 of the present invention.
Fig. 3 shows AFM analysis results of the graphene dispersion prepared in Example 2 of the present invention.
4 shows the Raman spectrum of the graphene dispersion prepared in Example 2 of the present invention.
5 shows the results of particle size measurement of the graphene dispersion prepared in Example 1 of the present invention.
Best Mode for Carrying Out the Invention Hereinafter, preferred embodiments are shown to facilitate understanding of the present invention. However, the following examples are intended to illustrate the present invention without limiting it thereto.
Example One
2.5 g of graphite (BNB90) and 0.25 g of a dye represented by the following formula (AK Scientific, Inc.) were mixed with 500 mL of water to prepare a feed solution (concentration of graphite: 5 mg / mL, concentration of dye: 0.5 mg / mL).
[Chemical Formula 1]
The feed solution was fed to the inlet of the high pressure homogenizer. The high pressure homogenizer has a structure including an inlet portion of the raw material, an outlet portion of the peeled product, and a microchannel connecting the inlet portion and the outlet portion and having a micrometer scale diameter. A high pressure of 1,600 bar was applied through the inlet to feed the feed solution and a high shear force was applied while passing a fine flow path having a diameter of 75 μm. The high pressure homogenization process was repeated by taking a part of the feed solution collected in the outlet portion as a sample and re-introducing the remainder into the inlet portion of the high pressure homogenizer. The high pressure homogenization process was repeated until 10 times, Respectively.
Example 2
Except that the feed solution (concentration of graphite: 5 mg / mL, dyestuff (manufactured by Dainippon Ink and Chemicals, Inc.) was used instead of the dye represented by
(2)
Example 3
(Concentration of graphite: 5 mg / mL, concentration of dye: 0.5 g) was prepared in the same manner as in Example 1, except that 0.5 g of a dye (Sigma Aldrich) 1 mg / mL) was prepared to prepare a graphene dispersion.
(3)
Experimental Example One
SEM and TEM images of the graphene dispersions prepared in Examples 1 to 3 were observed, and the results are shown in FIGS. 1 and 2.
As shown in FIG. 1 and FIG. 2, it was confirmed that the graphene flakes were well peeled off, and the fragrance of the chunks was small. This is because the benzene ring or naphthalene ring of the dye according to the present invention is well adsorbed to the graphene due to the interaction of π-π with the graphene and secures the dispersibility in the aqueous solution by the hydrophilic group and inhibits the adjacent graphenes from aggregating with each other .
Experimental Example 2
The graphene dispersion prepared in Example 2 was thinly coated on a Si / SiO 2 wafer and analyzed by AFM (atomic force microscopy). The results are shown in FIG.
As shown in FIG. 3, it was confirmed that the graphene existing in a single layer had a thickness of about 15 nm or less, and was well peeled off with a relatively thin thickness.
Experimental Example 3
The graphene dispersion prepared in Example 2 was thinly coated on a Si / SiO 2 wafer and Raman spectra were measured. The results are shown in FIG.
The ratio of I D / I G to Raman spectra is a result of measurement of the disordered carbon, which means sp3 / sp2 carbon consumption. Therefore, the larger the value of I D / I G , the higher the degree of change of sp 2 carbon of pure graphene to sp 3 carbon, which means that the characteristic inherent to pure graphene is weakened.
Conventional known oxidized graphite prepared by the Hummer's manufacturing process is the Raman spectrum of the I D / I G ratio of the number of defect occurs so close to about 1.0, but 4 Example 2 yes the pin dispersion I D prepared as shown in / I G value is 0.113, which is larger than that of pure graphite (BNB90), but it is confirmed that the defects are significantly smaller.
Experimental Example 4: Grapina Particle size analysis
In the manufacturing process of Example 1, the graphene particle size (lateral size) was analyzed according to the number of high pressure homogenization treatments, and the results are shown in FIG. 5 and Table 1 below.
As shown in FIG. 5 and Table 1, it was confirmed that as the number of high pressure homogenization treatments was increased, the size of graphene became smaller and the deviation became smaller, and thus uniform graphene was produced.
Claims (10)
The feed solution, including in the anthraquinone, triphenylmethane, phthalocyanine or azobenzene structure molecules, and -SO 2 O -, graphene production method including a dye containing a substituent.
Wherein the dye is any one or more of the following compounds:
Manufacturing method:
Wherein the dye is any one or more of compounds represented by the following general formulas (1) to (3)
Manufacturing method:
[Chemical Formula 1]
(2)
(3)
Wherein the concentration of the dye in the feed solution is from 0.1 mg / mL to 2 mg / mL.
Gt;
Characterized in that the concentration of graphite in the feed solution is from 0.5 to 5%
Gt;
Wherein the graphite in the feed solution is peeled while passing through the fine flow path under application of a shear force to produce graphene.
Gt;
Characterized in that the microchannel has a diameter of 10 to 800 mu m.
Gt;
Wherein the feed solution flows into the inlet of the high-pressure homogenizer under pressure of 100 to 3000 bar and passes through the microchannel.
Gt;
The solvent of the feed solution can be selected from the group consisting of water, N-methyl-2-pyrrolidone, acetone, N, N-dimethylformamide, DMSO, CHP, N-dodecyl-pyrrolidone ), Benzyl benzoate, N-octyl-pyrrolidone, dimethyl-imidazolidinone, cyclohexanone, dimethylacetamide, NMF (N-Methyl Formamide), bromobenzene, chloroform, chlorobenzene, benzonitrile , Quinoline, benzyl ether, ethanol, isopropyl alcohol, methanol, butanol, 2-ethoxyethanol, 2-butoxyethanol, 2-methoxypropanol, tetrahydrofuran (THF), ethylene glycol, , Methyl ethyl ketone (butanone), alpha-terpineol, formic acid, ethyl acetate and acrylonitrile.
Gt;
And the step of passing the recovered material recovered from the outlet to the high pressure homogenizer is repeatedly performed one to nine times.
Gt;
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1020150063875A KR102018288B1 (en) | 2015-05-07 | 2015-05-07 | Method for preparation of graphene by using dye |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1020150063875A KR102018288B1 (en) | 2015-05-07 | 2015-05-07 | Method for preparation of graphene by using dye |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| KR20160131454A true KR20160131454A (en) | 2016-11-16 |
| KR102018288B1 KR102018288B1 (en) | 2019-09-04 |
Family
ID=57540998
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| KR1020150063875A KR102018288B1 (en) | 2015-05-07 | 2015-05-07 | Method for preparation of graphene by using dye |
Country Status (1)
| Country | Link |
|---|---|
| KR (1) | KR102018288B1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108002368A (en) * | 2017-11-29 | 2018-05-08 | 温州医科大学 | A kind of amino anthraquinones modified graphene GDAQ and preparation method thereof is with preparing the application on hydrazine Huang luciferase assay reagent |
| CN110157007A (en) * | 2019-06-04 | 2019-08-23 | 厦门理工学院 | The preparation method and application of frosting graft grapheme and anthraquinone compounds |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101109961B1 (en) * | 2010-11-29 | 2012-02-15 | 주식회사 오리엔트정공 | Method for fabricating of graphene |
| KR20120049679A (en) * | 2010-11-09 | 2012-05-17 | 한국전기연구원 | Manufacturing method of single-layered reduced graphene oxide dispersion solution using shear stress and the single-layered reduced graphene oxide dispersion solution thereby |
| KR20130004638A (en) * | 2011-07-04 | 2013-01-14 | (주)월드튜브 | Method for mixed dispersion of graphene and graphite nanoplatelets and method for mixed powder of graphene and graphite nanoplatelets |
| KR101488410B1 (en) * | 2012-12-04 | 2015-01-30 | 서울대학교산학협력단 | Method for manufacturing reduced graphite oxide and reduced graphite oxide using thereof |
| KR20150018034A (en) * | 2013-08-08 | 2015-02-23 | 세종대학교산학협력단 | Graphene-nanoparticle composite, use of the composite, fabrication method of the composite |
-
2015
- 2015-05-07 KR KR1020150063875A patent/KR102018288B1/en active IP Right Grant
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20120049679A (en) * | 2010-11-09 | 2012-05-17 | 한국전기연구원 | Manufacturing method of single-layered reduced graphene oxide dispersion solution using shear stress and the single-layered reduced graphene oxide dispersion solution thereby |
| KR101109961B1 (en) * | 2010-11-29 | 2012-02-15 | 주식회사 오리엔트정공 | Method for fabricating of graphene |
| KR20130004638A (en) * | 2011-07-04 | 2013-01-14 | (주)월드튜브 | Method for mixed dispersion of graphene and graphite nanoplatelets and method for mixed powder of graphene and graphite nanoplatelets |
| KR101488410B1 (en) * | 2012-12-04 | 2015-01-30 | 서울대학교산학협력단 | Method for manufacturing reduced graphite oxide and reduced graphite oxide using thereof |
| KR20150018034A (en) * | 2013-08-08 | 2015-02-23 | 세종대학교산학협력단 | Graphene-nanoparticle composite, use of the composite, fabrication method of the composite |
Non-Patent Citations (2)
| Title |
|---|
| Carbon. 2013, Vol. 53, pp. 357~365 (2012.11.17.)* * |
| Chin. Sci. Bull. 2014, Vol. 59, pp. 1794~1799 (2014.04.04.)* * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108002368A (en) * | 2017-11-29 | 2018-05-08 | 温州医科大学 | A kind of amino anthraquinones modified graphene GDAQ and preparation method thereof is with preparing the application on hydrazine Huang luciferase assay reagent |
| CN110157007A (en) * | 2019-06-04 | 2019-08-23 | 厦门理工学院 | The preparation method and application of frosting graft grapheme and anthraquinone compounds |
Also Published As
| Publication number | Publication date |
|---|---|
| KR102018288B1 (en) | 2019-09-04 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| KR101682007B1 (en) | Preparation method of graphene | |
| JP6208364B2 (en) | Graphene production method and graphene dispersion composition | |
| US10472242B2 (en) | Method for preparing graphene by using high speed homogenization pretreatment and high pressure homogenation | |
| Zhang et al. | Production of graphene sheets by direct dispersion with aromatic healing agents | |
| KR101264316B1 (en) | manufacturing method of single-layered reduced graphene oxide dispersion solution using shear stress and the single-layered reduced graphene oxide dispersion solution thereby | |
| US10472243B2 (en) | Industrial method for preparing large-sized graphene | |
| US20170217775A1 (en) | Partially oxidized graphene and method for preparing same | |
| WO2015099457A1 (en) | Production method for graphene | |
| CN107221387B (en) | Preparation method of high-conductivity graphene film based on transient framework | |
| JP5800678B2 (en) | Nanocarbon aqueous dispersion, method for producing the same, and nanocarbon-containing structure | |
| WO2015099378A1 (en) | Graphene production method, and graphene dispersion composition | |
| WO2017063026A1 (en) | Dispersions | |
| KR20110101668A (en) | Manufacturing method of graphene compound with excellent dispersability in organic solvents | |
| EP3699214B1 (en) | Method for preparing graphene using a block copolymer | |
| KR20160131454A (en) | Method for preparation of graphene by using dye | |
| KR102049575B1 (en) | Method for preparation of graphene by using a polyethyleneoxide-based dispersion | |
| KR102086764B1 (en) | Method for preparation of graphene | |
| KR101970502B1 (en) | Graphene, and method of manufacturing the same | |
| KR20160131660A (en) | Method for preparation of graphene | |
| KR20170067475A (en) | Method of preparation for graphene dispersion | |
| Miao et al. | Enrichment of semiconducting single-walled carbon nanotubes by simple equipment and solar radiation |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| E902 | Notification of reason for refusal | ||
| E701 | Decision to grant or registration of patent right | ||
| GRNT | Written decision to grant |