KR20130127025A - Copper precursors with aminothiolate, preparation method thereof and process for the formation of thin films using the same - Google Patents

Abstract

The present invention relates to a copper precursor represented by chemical formula 1, wherein the copper precursor includes sulfur, has no need of adding separate sulfur during manufacturing thin films, and improves thermal stability and volatility, thereby allowing high quality copper sulfide thin films. In chemical formula 1, R1 and R2 are linear or branched alkyl of C1-C10, respectively, R3 and R4 are linear or branched alkyl of C1-C10 or fluorinated alkyl of C1-C10, respectively, and n is selected from numbers 1 to 3.

Description

Copper precursor using aminothiolate ligand, method for preparing same, and method for forming thin film using same

The present invention relates to a novel copper precursor, and more particularly, a copper precursor and a method for preparing the copper sulfide thin film, and a method for producing the copper sulfide thin film, which can be easily manufactured at a low temperature and have improved thermal stability and volatility. It is about how to.

Thin-film solar cells using CuIn _x Ga _{1 - x} Se ₂ (CIGS) thin films are thinner than conventional solar cells that use silicon crystals and have stable characteristics over long periods of time. As a result, it is known that there is a high possibility of commercialization as a highly efficient thin film solar cell that can replace the silicon crystalline solar cell.

However, compound-based solar cells using CIGS as a light absorbing layer have a great difficulty in commercialization because they use toxic substances and expensive rare elements. Therefore, the development of solar cells based on the Cu ₂ ZnSnS ₄ (CZTS) light absorbing layer, which replaces CIGS with earth-rich and inexpensive zinc (Zn) and tin (Sn), is drawing attention. .

In order for CZTS, which is used as a p-type light absorbing layer, to be manufactured as a solar cell having high efficiency, the band gap energy of CZTS should have a value in the range of 1.4 to 1.5 eV and the absorption coefficient is 10 ⁴ cm. ^It must have an optical characteristic of ^{? 1} or more. To this end, CZTS manufacturing research is being actively conducted at home and abroad through various methods such as co-evaporation, sputtering, and sol-gel methods.

As a process for forming the CZTS thin film, chemical vapor deposition (CVD) or atomic layer deposition (ALD) has been used to deposit a layer containing a metal.

However, when manufacturing the CZTS thin film by the CVD or ALD process as described above, since the deposition degree and the deposition control characteristics are determined according to the characteristics of the metal precursor, it is necessary to develop a metal precursor having excellent characteristics. To this end, Korean Patent Publication No. 10-2011-0085721 or Korean Patent Publication No. 10-2011-0112977 et al.

However, in the above documents, the precursors of the elements are not studied, and studies on the synthesis of precursors of copper, zinc, and tin required for the production of CZTS thin films are insufficient. Especially in the case of copper precursors, there is an urgent need for the development of precursors with improved thermal stability, chemical reactivity, volatility and deposition rate of copper metal.

KR 10-2011-0085721 A KR 10-2011-0112977 A

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems, and to provide a new copper precursor capable of producing a good quality copper sulfide thin film at low temperature with improved thermal stability and volatility.

In order to achieve the above object, the present invention provides a copper precursor represented by the following formula (1).

 [Formula 1]

(Wherein R 1 and R 2 are each independently a linear or branched alkyl group of C 1 -C 10, R 3 and R 4 are each independently C 1 -C 10 linear or branched alkyl group, or a C 1 -C 10 fluorinated alkyl group, n Is 1 to 3.)

In another aspect, the present invention provides a method for producing a copper precursor represented by the formula (1) comprising reacting a compound represented by the formula (2) and a compound represented by the formula (3).

(2)

Wherein M is any one of Li, Na, and K, R1 and R2 are each independently a linear or branched alkyl group of C1-C10, and R3 and R4 are each independently a linear or branched alkyl group of C1-C10. Or a C1-C10 fluorinated alkyl group, n is 1 to 3.)

 (3)

CuX

Wherein X is Cl, Br or I.

[Formula 4]

CuX ₂

Wherein X is Cl, Br or I.

In another aspect, the present invention provides a method for growing a copper sulfide thin film using the copper precursor of the formula (1).

Copper precursor represented by the formula (1) of the present invention is a precursor containing sulfur because it has the advantage of improving the thermal stability and volatility, and does not need to add a separate sulfur during thin film manufacturing, it is easy to use a high quality copper sulfide thin film It can manufacture.

1 is a ¹ H NMR spectrum for [Cu (dmampS)] ₄ .
2 is a crystal structure for [Cu (dmampS)] ₄ .
3 is TG data for [Cu (dmampS)] ₄ .
4 is XRD data for nanomaterials obtained after pyrolysis of [Cu (dmampS)] ₄ .
5 is EDS data and SEM photographs of nanomaterials obtained after pyrolysis of [Cu (dmampS)] ₄ .
FIG. 6 is a photograph showing dispersion of nanomaterials obtained after pyrolysis of [Cu (dmampS)] ₄ .

The present invention relates to a copper precursor represented by the following general formula (1):

[Formula 1]

(Wherein R 1 and R 2 are each independently a linear or branched alkyl group of C 1 -C 10, R 3 and R 4 are each independently C 1 -C 10 linear or branched alkyl group, or a C 1 -C 10 fluorinated alkyl group, n Is 1 to 3.)

In Formula 1, of R 1 to R 4 selected from C 1 to C 10 linear or branched alkyl groups, R 1 and R 2 are each independently CH ₃ , C ₂ H ₅ , CH (CH ₃ ) ₂ and C (CH ₃ ). is selected from _3, R3, R4, it is preferable to use the mutually independently selected from _{CH 3, CF 3, C 2} H 5, CH (CH 3) 2 and C (CH _{3) 3.}

The copper precursor represented by Chemical Formula 1 according to the present invention may be more specifically represented by general formula [Cu (daat)] ₄ (daat = dialkylaminoalkylthiolate), and the compound may be represented by the following Chemical Formula 2 as a starting material ( M (daat)) and the compound represented by the formula 3 to 4 may be prepared by inducing a substitution reaction by reacting in an organic solvent.

(2)

Wherein M is any one of Li, Na, and K, R1 and R2 are each independently a linear or branched alkyl group of C1-C10, and R3 and R4 are each independently a linear or branched alkyl group of C1-C10. Or a C1-C10 fluorinated alkyl group, n is 1 to 3.)

(3)

CuX

Wherein X is Cl, Br or I.

[Formula 4]

CuX ₂

Wherein X is Cl, Br or I.

In Formula 2, of R 1 to R 4 selected from a linear or branched alkyl group of C 1 -C 10, R 1 and R 2 are each independently CH ₃ , C ₂ H ₅ , CH (CH ₃ ) ₂ and C (CH ₃ ). is selected from _3, R3, R4, it is preferable to use the mutually independently selected from _{CH 3, CF 3, C 2} H 5, CH (CH 3) 2 and C (CH _{3) 3.}

Toluene, tetrahydrofuran, or the like may be used as the reaction solvent, and toluene may be preferably used.

Specific reaction process for producing a copper precursor of the present invention can be represented by the following scheme 1.

[Reaction Scheme 1]

In addition, another reaction process for preparing the copper precursor of the present invention can be represented by the following scheme 2.

[Reaction Scheme 2]

According to Schemes 1 and 2, after performing a substitution reaction for 12 to 24 hours at room temperature in a solvent such as toluene and tetrahydrofuran, the filtrate was removed under reduced pressure to obtain a yellow solid compound. In addition, by-products may be generated during the reaction of Scheme 1 or 2, and new copper precursors of high purity may be obtained by removing them by sublimation or recrystallization.

In these reactions, the reactants are used in stoichiometric equivalents.

The new copper precursor represented by Formula 1 is a yellow solid which is stable at room temperature, and is thermally stable and has good volatility.

When the copper sulfide thin film is grown using the copper precursor, there is an advantage of not having to add additional sulfur during the thin film manufacturing process.

The novel copper precursor of the present invention can be preferably applied to a process using a chemical vapor deposition method (CVD) or an atomic layer deposition method (ALD), which is widely used as a precursor for manufacturing a copper sulfide thin film.

The present invention may be better understood by the following examples, which are for the purpose of illustrating the invention and are not intended to limit the scope of protection defined by the appended claims.

Example

Synthesis of Copper Precursor Materials

Example 1: Preparation of [Cu (dmampS)] ₄

CuCl (1.5g, 0.015 mol, 1eq) and Li (dmampS) (2.1g, 0.015 mol, 1eq) were added to a 125 mL Schlenk flask and toluene (50 mL) was added thereto, followed by stirring for 24 hours. After filtering the obtained solution, the filtrate was removed solvent under reduced pressure to give a yellow solid compound. To remove impurities, the obtained product was recrystallized in hexane to give 2.55 g of a yellow crystal compound (yield: 86%).

¹ H-NMR (C ₆ D ₆ ) for the obtained compound is shown in FIG. 1.

¹ H NMR (C ₆ D ₆ , 300.13 MHz): δ 2.4496 (s, 6H), 2.3219 (s, 2H), 1.5188 (s, 6H).

FT-IR (KBr, cm ⁻¹ ): ν _MS 586, 447.

EA: calcd. (Found) Cu ₄ C ₂₄ H ₅₆ N ₄ S ₄ : C 36.81 (37.23); H 7.21 (7.28);

                               N 7.15 (7.36); S 16.38 (18.02)

EI-MS (m / z): 783 (M ⁺ )

Example 2: Preparation of [Cu (dmampS)] ₄

CuCl ₂ (0.135g, 0.001mol, 1eq) and Li (dmampS) (0.280g, 0.002mol, 2eq) were added to a 125 mL Schlenk flask, and toluene (50 mL) was added thereto, followed by stirring for 24 hours. After filtering the obtained solution, the filtrate was removed solvent under reduced pressure to give a yellow solid compound. To remove impurities, the obtained product was recrystallized in hexane to obtain 0.15 g of a yellow crystal compound (yield: 80%).

¹ H-NMR (C ₆ D ₆ ) for the obtained compound is shown in FIG. 2.

¹ H NMR (C ₆ D ₆ , 300.13 MHz): δ 2.4496 (s, 6H), 2.3219 (s, 2H), 1.5188 (s, 6H).

FT-IR (KBr, cm ⁻¹ ): ν _MS 586, 447.

EA: calcd. (Found) Cu ₄ C ₂₄ H ₅₆ N ₄ S ₄ : C 36.81 (37.23); H 7.21 (7.28);

                               N 7.15 (7.36); S 16.38 (18.02)

EI-MS (m / z): 783 (M ⁺ )

In order to confirm the specific structure of the copper precursor compound synthesized in Examples 1 and 2, the crystal structure (X-ray structure) was confirmed using a Bruker SMART APEX II X-ray Diffractometer, and is shown in FIG. 2. Through this, the structure of [Cu (dmampS)] ₄ could be confirmed.

In addition, thermogravimetric analysis (TGA) was used to measure the thermal stability, volatility, and decomposition temperature of [Cu (dmampS)] ₄ . The TGA method injected argon gas at a pressure of 1.5 bar / min while warming the product to 900 ° C. at a rate of 10 ° C./min. A TGA graph of the copper precursor compound synthesized in Example 1 is shown in FIG. 3. The copper precursor compound obtained in Example 1 had a mass loss around 174 ° C and a mass loss of 50% or more was observed at 243 ° C. Through this, it was confirmed that the TG graph T _1/2 is 208 ℃.

Pyrolysis of Copper Precursor Materials

After heating Oleylamine to 270 ° C, the copper precursor compound synthesized in Examples 1 and 2 was added together with toluene, and pyrolyzed for 30 minutes. After cooling to room temperature and washing twice with methanol and toluene, the obtained material was analyzed by XRD (X-ray diffraction analysis) and energy dispersive spectroscopy (EDS). XRD (X-ray diffraction analysis) is shown in FIG. 4, and an analysis result and an SEM photograph by EDS (energy dispersive spectroscopy) method are shown in FIG. 5, respectively. XRD (X-ray diffraction analysis) results and found to be consistent with existing known data value _{JCPDS 056-0256 Cu 1 .8 S, EDS} (energy dispersive spectroscopy) results roneun was found that Cu ₂ S. In addition, in order to measure the dispersion degree, the nanomaterials obtained by pyrolysis were sonicated for 10 minutes, and then, their dispersion degree was examined one day later. As a result, it has an excellent dispersion degree as shown in FIG.

Claims (5)

Copper precursor represented by the following formula (1):
[Formula 1]

(Wherein R 1 and R 2 are each independently a linear or branched alkyl group of C 1 -C 10, R 3 and R 4 are each independently C 1 -C 10 linear or branched alkyl group, or a C 1 -C 10 fluorinated alkyl group, n Is 1 to 3.) The method according to claim 1,
R 1 and R ₂ are independently selected from CH ₃ , C ₂ H ₅ , CH (CH ₃ ) ₂ and C (CH ₃ ) ₃ , and R 3 and R 4 are independently of each other CH ₃ , CF ₃ , C ₂ H ₅ , CH (CH ₃ ) ₂ and C (CH ₃ ) ₃ . Method for producing a copper precursor represented by the formula (1) of claim 1 comprising reacting a compound represented by the formula (2) and a compound represented by the formula (3-4):
(2)

Wherein M is any one of Li, Na, and K, R1 and R2 are each independently a linear or branched alkyl group of C1-C10, and R3 and R4 are each independently a linear or branched alkyl group of C1-C10. Or a C1-C10 fluorinated alkyl group, n is 1 to 3.)
(3)
CuX
(Wherein X is Cl, Br or I).
[Chemical Formula 4]
CuX ₂
(Wherein X is Cl, Br or I). A method of growing a copper sulfide thin film using the copper precursor of claim 1. The method of claim 4,
Wherein the thin film growth process is performed by chemical vapor deposition (CVD) or atomic layer deposition (ALD).

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