KR20070073170A - Process for synthesizing copper selenide compound using ultrasonic vibration - Google Patents

Abstract

A process for preparation of copper selenide compound for absorption layer of solar cell is provided to produce the compound useful as a reactive material of the absorption layer of Cu(In,Ga)Se2, to easily regulate size and distribution of particles in the compound without alternative heat treatment by applying ultrasonic vibration to a mixture of copper chlorides and selenous acid to induce chemical reaction. The process includes adding Cu chloride and selenous acid to a constant amount of solvent and applying ultrasonic vibration to the prepared solution to derive a chemical reaction to produce the copper selenide compound(CuSe2). Reaction products are CuCl2 and H2SeO3 combined together in a relative ratio of 1:0.5 to 1:5. The solvent is any one or more than two selected from a group consisting of ethyleneglycol, ethylenediamine, poly(ethyleneglycol) and poly(mono-butylether). The ultrasonic vibration is performed by applying ultrasonic wave at a power density of 10W/cm^2 to 1000W/cm^2 for 5 minutes to 3 hours.

Description

Process for Synthesizing Copper Selenide Compound Using Ultrasonic Vibration

1 is a schematic diagram of a reaction apparatus for the ultrasonic chemical reaction used in the embodiment of the present invention;

2A and 2B are electron microscopic (SEM) photographs of the copper selenide compound (CuSe ₂ ) crystals prepared in Example 1 of the present invention;

3 is a composition spectrum measurement graph for the copper selenide (CuSe ₂ ) compound prepared in Example 1 of the present invention;

4 is an X-ray diffraction (XRD) graph of the copper selenide (CuSe ₂ ) compound prepared in Example 1 of the present invention.

The present invention relates to a copper selenide compound which can be used as a reaction raw material of Cu (In, Ga) Se ₂ , which is a solar cell absorbing layer, and in particular, a method for producing CuSe ₂ , and more particularly, to preparing the compound. Ultrasonic (Ultrasonic vibration) is applied to the process to proceed with the reaction on the solution.The precise control of the reaction conditions such as the ultrasonic intensity and the processing time makes it easy to control the size and distribution of the particles. Since it can progress, it is related with the method of manufacturing a desired copper selenide compound by a high efficiency and a simple process.

There are not many methods for producing a copper selenide (CuSe ₂ ) compound, most of which relates to Cu _2-X Se, CuSe or Cu ₃ Se ₂ .

Examples of the preparation of such compounds by ultrasonic chemistry (see Y. Xie, X. Zheng, X. Jiang, J. Lu, and L. Zhu, Inorganic Chemistry, 41 , (2002), 387) As a method, CuI and Na ₂ SeSO ₃ are added to a solvent mixed with distilled water and ethanol, and sodium dodecyl sulfate is mixed with a surfactant, and a method of applying ultrasonic waves at 40 kHz and 100 W / cm ² is known. However, the above method can produce Cu _2-X Se, CuSe, Cu ₃ Se ₂ , but not CuSe ₂ .

On the other hand, the method of manufacturing CuSe ₂ is the only mechanical alloying (mechanical alloying) method, for example, after mixing the powder of Cu and Se to a mole ratio (high energy ball mill (high energy ball mill) (T. Ohtani, M. Motoki, K. Koh, K. Ohshima, Materials Research Bulletin, 30 , (1995), 1495). However, this method is disadvantageous in that it is impossible to control specific reaction conditions, and it is impossible to finely control the particle size and distribution of the product.

Accordingly, an object of the present invention is to solve the problems of the prior art as described above and the technical problems that have been requested from the past.

After in-depth study and various experiments, the present inventors prepared a copper selenide compound (CuSe ₂ ) using ultrasonic vibration, and thus, precisely controlling the particle size by precise control of ultrasonic intensity, reactant concentration and time. And since it is easy to control the distribution and does not require a separate heat treatment process, as a result, it can be confirmed that the copper selenide compound (CuSe ₂ ) can be produced in a high yield by a highly efficient and controllable process, and completed the present invention. It came to the following.

Therefore, in the method for preparing a copper selenide compound (CuSe ₂ ) according to the present invention, after adding copper chloride and selenic acid to a predetermined solvent, ultrasonic waves are applied to the solution to induce a chemical reaction between the two substances. And a process of producing a copper selenide compound (CuSe ₂ ).

Among the reactants, the copper chloride is preferably CuCl ₂ and the selenic acid is preferably H ₂ SeO ₃ . The CuCl ₂ may be used in the form of an anhydride or a hydrate, and more preferably, in the form of a hydrate (CuCl ₂ · 2H ₂ O).

The solvent may be selected from the group consisting of ethylene glycol, ethylenediamine, poly (ethylene glycol) and poly (mono-butyl ether). One or more selected may be preferably used. It is especially preferable when the reaction proceeds under ethylene glycol or ethylene diamine solvent.

The reactants are preferably mixed in a ratio (molar ratio) of 1: 0.5 to 1: 5. If the concentration of copper chloride is too high, there is a problem that Cu ₂ Se is easily formed, on the contrary, if the concentration of selenic acid is too high, Se is precipitated during the reaction.

The application of the ultrasonic wave is preferably performed for 5 minutes to 3 hours at a power density of 10 W / cm ² to 1000 W / cm ² , in particular 30 minutes to 2 hours at 100 to 200 w / cm ² . More preferably. If the ultrasonic power density is too low or the application time is too short, there are problems such as deterioration of the reaction efficiency due to unreacted reaction and precipitation of Se-only crystal. On the contrary, if the ultrasonic power density is too high or the application time is too long, the reaction solution may be overheated. It is not desirable because there is a problem.

The chemical reaction induced by the ultrasonic application may be expressed by, for example, Scheme 1 below.

CuCl ₂ 2H ₂ O + 2H ₂ SeO ₃ → CuSe ₂ + 4H ₂ O + Cl ₂ + 2O ₂

By applying ultrasonic waves to the reaction solution, a very high temperature (approximately 4500 ° C.) and pressure (hundreds of atmospheres) conditions are formed within a very short time (10 ns units) locally within the solution, and the intensity and time of the applied ultrasonic wave are precise. By adjusting the particle size and distribution is easy to control, no separate heat treatment process is required, and the desired copper selenide compound (CuSe ₂ ) can be obtained by a high efficiency and controllable manufacturing process.

Other processes may be added to the manufacturing method of the present invention without departing from the effects of the present invention, and all of them should be construed as being included in the scope of the present invention.

The present invention also provides a copper selenide compound (CuSe ₂ ) prepared by the above method.

The copper selenide compound produced by the above production method is composed of particles having an average particle diameter of 0.1 ㎛ to 10 ㎛.

Such copper selenide compounds include indium selenide compounds such as InSe and In ₂ Se ₃ and / or gallium seles such as GaSe and Ga ₂ Se _3, as disclosed in Korean Patent Application No. 2005-82723. It can be used to prepare Cu (In, Ga) Se ₂ absorbing layer suitable for high efficiency solar cell by reacting with nitide compounds. The contents of this application are incorporated herein by reference.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the following Examples are provided to illustrate the present invention, and the scope of the present invention is not limited thereto.

Example 1

0.597 g of CuCl ₂ H ₂ O and 0.451 g of H ₂ SeO ₃ were mixed in 50 ml of EG solvent (0.07 M / L ). The mixture was placed in a 80 ml vial and reacted for 1 hour without heating in an ultrasonic wave of 140 W / cm ² power density using a titanium horn 30 mm in diameter, as in FIG. Then, 0.7 g of white powder crystals were obtained by drying after precipitation and centrifugation.

Electron microscopy (SEM) photographs of the crystals are disclosed in FIGS. 2A and 2B, respectively (FIG. 2A: 5,000-fold photo, FIG. 2B: 25,000-fold photo). The photographs of FIGS. 2A and 2B were obtained at an acceleration voltage of 15 keV using a JSM-6340F electron microscope manufactured by JEOL, respectively. .

In addition, in order to analyze the composition of the material, the results of analyzing the characteristic transition energy of each element by energy dispersive spectrocopy (EDS) is shown in Figure 3 and Table 1 below. Meanwhile, Bruker's D4 endeavor diffractometer was used to confirm the phase of the synthesized material, and the X-ray diffraction (XRD) analysis results are shown in FIG. 4.

In Table 1, K and L after each element represent transition energies of orbital K and L atoms, respectively.

Example 2

In order to measure the composition of the product of Example 1 more quantitatively, the composition was analyzed using an ICP-optical emission spectrometer manufactured by Perkin Elmer, and the results of the analysis are shown in Table 2 below.

As shown in the results of Table 2, the ratio of Cu and Se of the product is 1: 2.08 and as shown in the XRD and ICP results, it can be seen that the resulting material is a copper selenide compound (CuSe ₂ ).

As described above, the method for producing a copper selenide compound (CuSe ₂ ) according to the present invention applies a ultrasonic wave to perform a reaction on a solution, and thus, precisely controls particle size and size by controlling the reaction conditions such as ultrasonic intensity and time. Since the distribution can be easily controlled and the reaction can proceed without a separate heat treatment, a desired copper selenide compound (CuSe ₂ ) can be manufactured by a simple process with high efficiency and control.

Those skilled in the art to which the present invention pertains will be able to perform various applications and modifications within the scope of the present invention based on the above contents.

Claims (9)

A copper selenide compound (CuSe ₂ ) is prepared by adding copper chloride and selenic acid to a predetermined solvent, and then applying a ultrasonic vibration to the solution to induce a chemical reaction. The method of claim 1 wherein the reactants are CuCl ₂ and H ₂ SeO ₃ . The method of claim 2, wherein said CuCl ₂ is in the form of anhydride or hydrate. The method of claim 1, wherein the reactants are mixed at a ratio of 1: 0.5 to 1: 5. The method of claim 1, wherein the solvent is one or more selected from the group consisting of ethylene glycol, ethylenediamine, poly (ethylene glycol) and poly (mono-butyl ether). 6. The method of claim 5 wherein the solvent is ethylene glycol or ethylenediamine. The method of claim 1, wherein the ultrasonic wave is applied for 5 minutes to 3 hours at a power density of 10 W / cm ² to 1000 W / cm ² . 8. The method of claim 7, wherein the ultrasound is applied at 100 to 200 w / cm ² for 30 minutes to 2 hours. Copper selenide compound (CuSe ₂ ) prepared by the method of claim 1 and having an average particle diameter of 0.1 μm to 10 μm.

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