JPS61215661A - Metal sulfide - Google Patents

Abstract

PURPOSE:To provide a compsn. mainly composed of a metal sulfide and a high-molecular compd., which can be used as a semiconductor, a power element for a solar cell, a commutating element, etc., by removing a solvent from a liquid material obtd. by dissolving a high-molecular material in a dispersion of a metal sulfide in a solvent in a state of a sol. CONSTITUTION:A sulfur compd. [e.g. H2S or (NH4)2S] is added to a soln. of a metal compd. [e.g. CdI2 or Cd(OCOCH3)2] in a solvent to prepare a liquid material contg. the metal sulfide in a state of a sol. A high-molecular material is dissolved in the liquid material to obtain a liquid material (apparently uniform soln.). The solvent is then removed from said liquid material by precipitation or evaporation to form the above compsn. Preferred solvents are compds. of the formula (wherein R, R' is H, alkyl). Preferred examples of the high- molecular compds. are those contg. a cyano, carbonyl or arom. group.

Description

[Detailed description of the invention] Metal sulfides have functions as semiconductors or catalysts,
It is used in various electric circuit elements. For example, CdS has photoconductivity (Kyoritsu Shuppan Kagaku Daijiten, Vol. 3, p. 585), and it is also possible to produce solar cells made of copper sulfide and cadmium sulfide. In addition, some metal sulfides are used as conductors, phosphors, or positive electrode active materials for batteries such as lithium batteries (for example, the above-mentioned ``Chemistry Encyclopedia'' Vol. 9, p. 645, Electrochemical
“Lithium Bat” published by Society (USA)
eries” p. 349, p. 381, p. 421 (1
981) etc.). However, metal sulfides generally have poor mechanical strength and are difficult to mold, making them difficult to form into film-like materials. On the other hand, polymer compounds have excellent moldability and are compounds from which film-like materials can be easily obtained. The present invention takes advantage of the features of both to obtain a composition comprising both. That is, the present invention relates to a composition comprising a metal sulfide that has electrically useful properties and a polymer compound that has excellent moldability but does not have the electrical and catalytic properties of metal sulfides. Useful substances with various functions can be obtained.

In the process of obtaining the composition of the present invention, the metal sulfide initially exists in the sol (colloidal solution) as fine particles with a radius of about 3 x 10 -5 cm or less and is in a highly dispersed state. Therefore, by making a polymer compound exist in a dissolved state in the liquid material containing highly dispersed metal sulfides, and then removing the solvent by a precipitation method, drying method, etc., the polymer compound is dissolved. A composition according to the invention is obtained in which the metal sulfide is highly dispersed. Therefore, the composition of the present invention is not simply a mixture of a metal sulfide and a polymer compound, but is a substance in which the metal sulfide is highly dispersed as fine particles, and the composition has a super thin film. It has an advantage in obtaining a functional film with a similar shape, and also has excellent functions and properties.

That is, the composition of the present invention has excellent physical properties due to being in such a highly dispersed state, and has a wide range of uses as semiconductors, rectifying elements, etc. In particular, in the present invention, a new sol of metal sulfides that has not been known until now (a new sol of copper sulfide, cadmium sulfide, etc. in sulfoxides and formamides represented by the molecular formula described in claim 4) This is also utilized in the production of the composition of the present invention, and one of the features of the present invention is the preparation of a new sol of this metal sulfide (i.e., sulfoxides and formamides are molecular compounds can be dissolved and thus compositions of various metal sulfides and polymeric compounds can be obtained by the present invention). The composition of the present invention is generally produced by adding a sulfur compound such as H2S or (NH4)2S to a solution containing a metal sulfide (a polymer compound may be dissolved in this solution from the beginning). A sol of metal sulfide is prepared, and a polymer (a water-soluble polymer compound in the case of a hydrosol, a polymer soluble in the organic solvent in the case of an organosol) is added and dissolved in this way. It can be obtained by removing the solvent from a liquid substance by reprecipitation, evaporation, etc. If necessary, the metal can be dissolved by dissolving the polymer in the solution before preparing the metal sulfide sol, or by further dissolving the polymer in the metal sulfide sol prepared using this polymer-containing solution. It is also possible to obtain a liquid substance containing a sulfide in the form of a sol and a polymer compound, and to obtain the composition of the present invention from these liquid substances. Next, examples of the present invention will be shown.

Example 1. Cadmium iodide (CdI2) is dissolved in N,N-dimethylformamide (20-40 ml per 1 g of CdI2). After degassing the solution, dry hydrogen sulfide gas (C
When 1.2 to 3.3 times the mole of dI2) is introduced at room temperature, the color of the solution, which was colorless before the reaction, turns yellow to yellow-orange (the characteristic cadmium yellow color of CdS).
The color changes. The visible light absorption spectrum of this solution is 450
shows a shoulder absorption band at nm, and the position of this absorption band has been reported for solid cadmium sulfide (J. Opt. Soc.
．． Am. , 46, 1013 (1965)). Also, when acetone, water, methyl alcohol, etc. are added to this solution, a yellow precipitate of cadmium sulfide (confirmed by the fact that the powder X-ray diagram matches that of commercially available CdS and by elemental analysis) is instantly formed. (The yield of CdS was 97 to 99% when 3.3 times the molar amount of H2S was added to CdI2). Therefore, it is clear that cadmium sulfide was produced by the above reaction, but once cadmium sulfide (CdS) has become a precipitate, it can no longer be used as N or N.
- It did not dissolve in dimethylformamide. Therefore, in the above reaction, the produced CdS is considered to exist in N,N-dimethylformamide as a sol (or in a metastable state). In fact, although the liquid substance obtained in the above reaction appears to be homogeneous, after the reaction is completed, the liquid substance is about -2
After standing at 0°C overnight and for about 2 hours at about 0°C, analysis by light scattering method using an argon laser revealed that CdI2
and H2S in N,N-dimethylformamide.
It was found that there were many fine particles having a radius of cm. When this liquid material was left under argon laser irradiation for about 7 hours, the radius of the fine particles increased to 7.0 x 10 -7 cm, but even in this state, the liquid material appeared uniform. From the above, it was found that this liquid substance contained CdS in a sol state. This sol is 1 below about 20℃.
It exists stably without precipitation for more than 0 hours, and about -
It existed stably for more than two weeks at a low temperature of 20°C. The radius of CdS particles in the sol varies depending on the preparation conditions and is 4 × 10-
The radius of the particles was in the range of 7 cm to 1.5 x 10-6 cm, and if the radius of the particles was larger than this (1.5 x 10-6 cm or more), precipitation tended to occur.

A portion of the CdS sol prepared as described above is taken, and polyacrylonitrile is added thereto and dissolved. At this time, Cd
S did not precipitate. A part of the apparently uniform solution obtained in this way is spread on a glass plate, and volatile substances such as solvents are removed using a vacuum system, resulting in an orange film (
Depending on the conditions, an orange transparent film was obtained. The electrical conductivity (σ) of this film at room temperature is the weight ratio of CdS in the film (hereinafter, the weight ratio of metal sulfide in a composition consisting of metal sulfide and polymer compound is referred to as R value).
The R value is 0.59, 0.64, 0.74.
3.7×10-6Scm-1, 8.0×10 respectively at the time of
-6Scm-1, 2.1 x 10-5Scm-1. In addition, σ of polyacrylonitrile is 5.1×1 at room temperature.
The σ of the material obtained by molding CdS obtained by adding acetone to the above organosol at a pressure of 400 kg/cm2 was 5.9 x 10-8 Scm-1. CdCl2, Cd(OCOCH3)2 to CdI2
It could also be used as an alternative raw material. Further, a composition consisting of CdS and polyvinyl formal was obtained in the same manner as in the above example except that polyvinyl formal was used instead of polyacrylonitrile. This composition (in film form) was also a semiconducting material having an electrical conductivity of about 1 x 10-7 Scm-1. The σ of these compositions consisting of CdS and a polymer compound increases by applying pressure, indicating that these compositions can be used as pressure-sensitive sensors. The physical properties of the composition composed of CdS and polyacrylonitrile prepared by this method change depending on heat treatment. For example, the activation energy for electrical conduction of a composition with an R value of 0.74 is 0.65 eV, but the activation energy for electrical conduction of a substance obtained by heat-treating this composition at 80°C for 3 hours is It is 0.91 eV. Similar sols and compositions were obtained using dimethyl sulfoxide in place of N,N-dimethylformamide.

Example 2. Anhydrous copper acetate (Cu(OCOCH3)2) 1.82g (1
After dissolving 0 mmol) in 100 ml of dimethyl sulfoxide, the gas in the container containing this solution was removed using a vacuum pump. Then, 18 mmol of H2S was added to this container and reacted at 30°C. As a result of this reaction, the color of the solution changed from blue-green to blue-green-black, and at the same time, a precipitate was formed. This precipitate was removed by filtration under an Ar flow to obtain a liquid substance that was uniform in appearance. Approximately 6.7 x 10-6 c
Powder X was found to contain many fine particles with a radius of
The solution was identified as copper sulfide (CuS) by line analysis and elemental analysis, and was found to be a solution containing copper sulfide in a sol state.

Take a portion of the copper sulfide sol prepared above, dissolve polyacrylonitrile therein, spread the resulting liquid substance on a glass plate, and use a vacuum system to remove volatile substances such as solvents (reactants). A composition consisting of copper sulfide and polyacrylonitrile was obtained by removing the acetic acid (containing acetic acid produced by the process). As a result of analysis by infrared spectroscopy, it was found that there was substantially no unreacted copper acetate in the composition. The composition thus prepared has an electrical conductivity (σ) of 1 x 10-4 Scm-1 when the R-value is 0.32, and an electrical conductivity (σ) of 1 x 10-2 Scm-1 when the R-value is 0.44. It was a semiconductor that exhibited electrical conductivity. The value of σ varies depending on delicate conditions during composition preparation, and in some cases, compositions having an order of magnitude larger than the above values were obtained. It was found that the copper sulfide sol prepared in this example is relatively stable and can withstand stable storage at room temperature, and the size of the copper sulfide particles does not change much when left standing.

A similar sol of copper sulfide can be obtained by using other copper compounds instead of Cu(OCOCH3)2, and in this practical example, ammonium sulfide ((NH4)2) is used instead of H2S.
A similar copper sulfide sol could be obtained using S). The copper sulfide-polyacrylonitrile composition of this example was dissolved in dimethyl sulfoxide to give an apparently homogeneous solution.

Example 3. 10 mmol of zinc iodide (ZnI2) was added to 50 ml of N
, N-dimethylformamide, and after removing the gas in the container using a vacuum pump, 22 mmol of H2S is added. The solution obtained in this way was initially transparent, but a white precipitate formed over time, and this white precipitate was found to be zinc sulfide (ZnS) containing an amorphous part from the results of powder X-ray analysis. Ivy. As a result of analyzing the state before the formation of this white precipitate using a light scattering method using an Ar laser, it was found that after the reaction solution was left at 25°C for about 30 minutes, the apparently uniform liquid substance had a radius of about 1.5× It was found that many particles of 10-6 cm (150A) were contained. After about 50 minutes, the radius of the particles increases to about 4 x 10-6 cm, and after about 60 minutes and 70 minutes, the radius of the particles increases to about 1 x 15-5 cm and 2.4 x 10 cm, respectively.
It was found that the ZnS white precipitate described above would be formed if the thickness was left longer than -5 cm. The electrical conductivity of the film-like composition obtained by dissolving polyacrylonitrile in a liquid substance before the white precipitate is formed and removing volatile components under vacuum has an R value of 0.2. Sometimes about 2x
It was found that the value in the semiconductor region was 10<-8>Scm<-1>. It has also been found that a semiconducting composition can be obtained when poly(2-vinylpyridine) is used instead of polyacrylonitrile. Also, ZnCl2, Z instead of zinc iodide
It was found that a zinc sulfide sol similar to that of this example can be obtained even when a zinc compound such as n(OCOCH3)2 is used.

Example 4. 10 mmol of nickel acetate (Ni(OCOCH3)2)
・4H2O) was dissolved in 100ml of dimethyl sulfoxide, degassed, and 22mmol of H2S was added at 20°C.
When reacted with , the color of the solution changes from green to black. After standing overnight, the black precipitate was removed by filtration in an argon stream to obtain a black liquid substance with uniform appearance. When acetone was added to this liquid substance, a black precipitate was formed, and elemental analysis revealed that this black precipitate was nickel sulfide (NiS).

Once precipitated, NiS does not dissolve in dimethyl sulfoxide, and on the other hand, analysis of the aforementioned black liquid substance by a light scattering method using an Ar laser revealed that this liquid substance has a radius of 2 × 10 cm ( 20■, the detection limit of this light scattering method), it became clear that there were no particles with a size larger than
It is thought that the particles are contained in a sol state as fine particles of 0 cm or less. Take a portion of the above solution (liquid substance), add polyacrylonitrile to it, dissolve it, spread it on a glass plate, remove volatile substances under vacuum, and add N.
A composition consisting of iS and polyacrylonitrile was obtained. The electrical conductivity (σ) of this composition has an R value of 0.14, 0.1
9,0.32, respectively 3.5×10-6Scm-1,1
．． 2×10-5Scm-1, 1.3×10-4Scm-
1 (value at room temperature), indicating that this composition is a semiconductor. In this example, the NiS recovered by adding acetone was collected at 400 kg/cm2.
The σ of the material obtained by molding under the pressure of is 7.5 × 10-
It was 8 Scm-1.

Example 5. Example 2. Cu (
Cu obtained by the reaction of OCOCH3)2 and H2S
8 of vinylidene chloride and acrylonitrile in the S sol
A 0:20 copolymer (sold by Polysciences) was dissolved in Example 2. A composition consisting of CuS and this copolymer was obtained in the same manner as above. This composition has an R value of 0.48, 0.33, 0.24, 0.19 at room temperature.
4.3×10-3Scm-1, 3.0×10 respectively when
-4Scm-1, 2.4×10-6Scm-1, 8.6
It was found that it was a semiconductor exhibiting an electrical conductivity of x10<-7>Scm<-1>. Furthermore, a composition consisting of CuS and the polymer compound was similarly obtained using poly(ethyl methacrylate). This composition has an R value of 0.47 at room temperature.
4.0×10-2Scm at 0.24 and 0.19 respectively
-1,1.8×10-2Scm-1,6.6×10-4
It was found that it was a semiconductor having an electrical conductivity of Scm-1.

Example 6. HgCl2, Pd(OCOCH3)2, Mn(O
By reacting COCH3)2.4H2O with H2S, a sol containing HgS, PdS, and MnS, respectively, was obtained. Polyacrylonitrile is dissolved in these sol,
The corresponding composition containing metal sulfide and polyacronitrile was obtained by removing volatile substances under vacuum. These compositions exhibited semiconducting properties. Further, a semiconducting material was obtained in the same manner using CuI as a reaction raw material.

Example 7. Example 2. The composition (R value = 0.44) made of CuS and polyacrylonitrile prepared in 1.
cm2) by coating and then removing volatile components under vacuum (film thickness = 0.07 mm). When a platinum plate was placed on this film and the current-voltage characteristics between it and Nesa Glass were measured by a contact method, it was found that the contact between the composition and Nesa Glass was ohmic. On the other hand, Example 1. A composition consisting of CdS and polyacrylonitrile as prepared in
R value = 0.74) was obtained by the method of coating on the Nesa glass and removing volatile components under vacuum (film thickness = 0.74).
05mm). In this case as well, the contact between the composition and Nesa glass was ohmic. In this way, a film of CdS-polyacrylonitrile composition and a film of CuS-polyacrylonitrile composition are respectively formed on separate Nesa glass, and both films are crimped to form a current-voltage (i-V
) characteristics were investigated. As a result, when a voltage of 5V was applied with the film containing CuS on the opposite side and the film containing CdS on one side, a current of 5μA/cm2 flowed, but when the direction of voltage application was reversed, a current of 5μA/cm2 flowed. It was found that there is a rectifying effect in that when a voltage of 5V is applied, only a current of 0.6 μA/cm2 flows. In this way, a device having a rectifying function can be manufactured using a composition of CuS and polyacrylonitrile and a composition of CdS and polyacrylonitrile.

Example 8. Example 7. A composition of CuS and polyacrylonitrile obtained by the method described above and a composition of CdS and polyacrylonitrile (both films shown in Example 7) were bonded together,
When fluorescent light is irradiated from the side of the dS and polyacrylonitrile composition through Nesa glass (transparent glass), approximately 1
An output current of mA/cm2 was obtained.

Example 9. Example 2. A composition (R value = 0.44) consisting of CuS and polyacrylonitrile similar to that prepared in
412, 2.5 x 5.0cm, R=1.05~1.6Ω
, n=5×1015cm-3, thickness=0.625cm)
It was obtained by a method in which volatile components were removed from the sol after it was coated on top of the sol. When we investigated the i-V characteristics between this CuS and polyacrylonitrile composition (film form) and an n-type silicon plate, we found that a voltage of 2.5V was obtained with the composition side as the positive side and the n-type silicon plate side as one side. 5m when applying (DC voltage)
Whereas a current of A/cm2 flows, when the direction of voltage is reversed and a voltage of 2.5V is applied, the current flows by 0.8m.
It was found that it has a rectifying property that only a current of A/cm2 flows.

Example 10. By electrolytically polymerizing thiophene at a constant current (2 mA/cm2) using LiBF4 as a supporting salt (Makrom
ol, Chem. , 185, 1295 (1984)) formed a thiophene polymer on Nesa glass. This membranous thiophene polymer (doped during electrolytic polymerization to become a p-type electrical conductor) and Example 7. The surfaces of the film composition of CdS and polyacrylonitrile formed on the Nesa glass prepared in step 1 were brought together and pressed together.

The IV characteristics between the thus obtained membranous thiophene polymer and the film composition were investigated. As a result, the film-like composition was placed on one side and the membranous thiophene polymer was placed on one side.
It was found that when a voltage of V is applied, a current of 0.6 mA/cm2 flows, but when the direction of voltage is reversed and a voltage of 2 V is applied, only a current of 0.03 mA/cm2 flows. . The film-like thiophene polymer is considered to be a p-type electrical conductor, and the composition of CuS and polyacrylonitrile was also found to be a p-type electrical conductor by Hall effect measurement. is considered to be an isoheterotype junction. Also, Toshiba (
Using a H-1001 mercury lamp (400 W) manufactured by Co., Ltd., light was irradiated through the Nesa glass from the side of the composition made of CuS and polyacrylonitrile of the main bond. As a result, in the forward direction (composition side is +), the current value increases to 1.4 mA/cm2 when the applied voltage is 2 V, whereas in the reverse direction, when the applied voltage is 2 V, the current value increases to 0.02 mA/cm2. The effect of light irradiation was seen, which decreased the amount by cm2. Example 7. ,9. and 10. All of the curves showing the i-V characteristics showed curves peculiar to junctions showing rectifying characteristics.

Example 11. A hydrosol containing FeS in a sol state (water is the dispersion medium) was prepared using a method similar to the method described in the literature (edited by the Chemical Society of Japan, "New Experimental Chemistry Course 18 Interfaces and Colloids" and Tokyo Chemical Society Journal 37, 671 (1916)). Obtained. In this hydrosol, poly(vinyl alcohol) (hydrolysis rate 98.5%,
Add and mix an aqueous solution containing Polysciences, Inc.). At this time, no formation of precipitate was observed.

A portion of the liquid substance obtained in this way was taken, spread on a glass plate, and then placed in a dryer at about 100°C to evaporate the water, producing a semiconducting material made of FeS and poly(vinyl alcohol). A composition (film-like) was obtained.

Claims (10)

[Claims] (1) A composition containing a metal sulfide in the form of a sol and obtained by removing the solvent from a liquid substance containing a polymer compound, the composition having a metal sulfide and a polymer compound as main components. (2) The composition according to claim 1, wherein the metal sulfide is obtained by reacting a monovalent or divalent metal compound with a sulfur compound. (3) The composition according to claim 1 or 2, wherein the metal sulfide is any one of copper sulfide, cadmium sulfide, nickel sulfide, mercury sulfide, zinc sulfide, and palladium sulfide. . (4) As a solvent constituting a liquid substance, there are molecular formulas ▲ mathematical formulas, chemical formulas, tables, etc. ▼ or ▲ mathematical formulas, chemical formulas, tables, etc. ▼ (R and R' represent H or a substituent such as an alkyl group) ) or a compound represented by any of the above molecular formulas as the main component of the solvent. Composition. (5) The composition according to any one of claims 1 to 4, which is obtained using a compound having a cyano group, a carbonyl group, or an aromatic group as a polymer compound. (6) A method of using the composition according to any one of claims 1 to 5 as a semiconductor. (7) A method of using the composition according to any one of claims 1 to 5 as a power generation element of a solar cell. (8) A method of using the composition according to any one of claims 1 to 5 as a rectifying element. (9) A method of using the composition according to any one of claims 1 to 5 as a pressure or light sensor. (10) A compound represented by either the molecular formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ or ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (R and R' represent substituents such as alkyl groups). A sulfur compound is added to a solution obtained by dissolving a metal compound in a solvent to prepare a liquid substance containing a metal sulfide in a sol state, and this liquid substance is used to claim a patent. A method for obtaining a composition according to any one of items 1 to 5.