JPS61218640A - Porous organic semiconductor - Google Patents

Abstract

PURPOSE:To provide a porous organic semiconductor having excellent heat- resistance and oxidation resistance, consisting of a heat-treated product of a specific aromatic condensation polymer having a polyacene skeleton structure with a specific C/H atomic ratio and containing minute interconnected pores. CONSTITUTION:An aromatic condensation polymer obtained by the condensation of an aromatic hydrocarbon compound having phenolic hydroxyl group and an aldehyde is heat-treated to obtain a porous semiconductor having a polyacene skeleton structure with a C/H atomic ratio of 0.6-0.05 and containing interconnected pores having average diameter of <=10mum. It can be produced by pouring an aqueous solution containing a precondensate and an inorganic salt into a mold, heating the solution while suppressing the evaporation of water to obtain a hardened product having the form of a film or cylinder, removing the inorganic salt therefrom, and heat-treating the resultant porous cured condensate in a nonoxidizing atmosphere at 400-800 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to porous organic semiconductors. More specifically, the present invention relates to a porous organic semiconductor that is a heat-treated product of an aromatic condensation polymer that is a condensation product of an aromatic hydrocarbon compound having a phenolic hydroxyl group and an aldehyde.

[Conventional technology]

Polymer materials are excellent in moldability, light weight, and mass production. Therefore, by taking advantage of these properties of polymer materials, organic polymer materials that have electrical semiconductivity are desired in many industrial fields including the electronics industry. Early organic semiconductors were difficult to form into films or plates, and they did not have properties as n-type or p-type impurity semiconductors, so their uses were limited.

In recent years, organic semiconductors with relatively excellent moldability have become available, and by doping these semiconductors with electron-donating dopants or electron-accepting dopants, they can be made into n-type or p-type organic semiconductors. It became possible. Polyacetylene is a typical example of such an organic semiconductor. This organic semiconductor is approximately 10″″ (
It has an electrical conductivity of Ω−α)″1, but AsF
The electrical conductivity can be greatly improved by doping with electron-accepting dopants such as , or electron-donating dopants such as Li, Nα, etc.
(The conductivity of Ω-OE has been obtained.

However, polyacetylene has the disadvantage of being easily oxidized by oxygen. For this reason, it is difficult to handle in the air, and it lacks practicality as an industrial material.

In addition, Japanese Patent Application Laid-open No. 58-1 filed by the same applicant as the present application
No. 36,649 discloses (A) a heat-treated product of an aromatic condensation polymer consisting of carbon, hydrogen and oxygen, which has a polyacene skeleton structure with an atomic ratio of hydrogen atoms/carbon atoms of 0.60 to α15; (B) an electron-donating doping agent or an electron-accepting doping agent, and (C) an electrically conductive organic polymer having higher electrical conductivity than the undoped substrate; Molecular-based materials are disclosed.

The above-mentioned insoluble and infusible substrate has excellent heat resistance and oxidation resistance,
Moreover, as described above, doping can be performed with an electron-donating doping agent or an electron-accepting doping agent, and an organic semiconductor exhibiting p-type or fi-type properties can be obtained. However, the above-mentioned publication does not describe anything about porous substrates or porous organic semiconductors.

On the other hand, ceramic porous bodies and carbon porous bodies are known as porous bodies having communicating pores with excellent heat resistance and chemical resistance, and are used in many industrial fields including steel materials.

However, porous organic semiconductors with excellent heat resistance and chemical resistance have not yet been developed, despite the great social needs of today's biotechnology era.

C. Problems to be Solved by the Invention] An object of the present invention is to provide a porous organic semiconductor.

Another object of the present invention is to provide a porous organic semiconductor having excellent heat resistance and oxidation resistance.

Still another object of the present invention is to provide an organic semiconductor having a large number of communicating pores that can be rapidly and uniformly doped with an electron-accepting dopant and/or an electron-donating dopant.

Still another object of the present invention is to provide an electron-accepting dopant and/or an organic semiconductor doped with an electron-accepting dopant.

Still another object of the present invention is to provide a porous organic semiconductor in the form of a film, plate, or the like.

Still another object of the present invention is to provide an organic semiconductor having fine communicating pores that is susceptible to various chemical reactions or physical adsorption.

Further objects and advantages of the present invention will be apparent from the following description.

[Means and effects for solving the problems] According to the present invention, the above-mentioned objects and advantages of the present invention are achieved by the following: A heat-treated polymer, comprising: (a) a hydrogen atom/carbon atom atomic ratio of 0.6 to α0;
5, and (b)
This is achieved by a porous bonded semiconductor characterized by having communicating pores with an average pore diameter of 10 μm or less.

The aromatic condensation polymer in the present invention is a condensate of an aromatic hydrocarbon compound having a phenolic hydroxyl group and an aldehyde. Suitable examples of such aromatic hydrocarbon compounds include so-called phenols such as phenol, cresol, and xylenol, but they are not limited thereto. For example, it can be a methylene-bisphenol represented by the following formula, where 2 and y are each independently 0.1 or 2, or it can also be a hydroxy-piphenyls or a hydroxynaphthalene. can.

Among these, phenols, particularly phenol, are practically preferred.

The aromatic condensation polymer in the present invention further includes one of aromatic hydrocarbon compounds having a phenolic hydroxyl group.
It is also possible to use a modified aromatic polymer in which part of the polymer is substituted with an aromatic hydrocarbon compound having no phenolic hydroxyl group, such as xylene, toluene, etc. For example, a modified aromatic polymer which is a condensation product of phenol, xylene, and formaldehyde can also be used.

In addition to formaldehyde, aldehydes include
Formaldehyde is preferred, although other aldehydes such as acetaldehyde and furfural can also be used. The phenol-formaldehyde condensate may be a norac type, a resol type, or a composite thereof.

The porous organic semiconductor of the present invention is a heat-treated product of the aromatic condensation polymer as described above, and can be produced, for example, as follows.

An initial condensate of an aromatic hydrocarbon compound having a phenolic hydroxyl group or an aromatic hydrocarbon compound having a phenolic hydroxyl group and an aromatic hydrocarbon compound having no phenolic hydroxyl group and aldehydes is prepared, and this initial condensate and Prepare an aqueous solution containing an inorganic salt, pour this aqueous solution into a suitable mold, and then heat the aqueous solution while suppressing the evaporation of water to shape it into a shape such as a plate, a film, or a cylinder in the mold. The cured product is cured and converted, and then the cured product is washed to remove inorganic salts contained in the cured product, and the resulting porous cured condensate is heated for 400 min in a non-oxidizing atmosphere.
Heat treatment to a temperature of ~800°C.

The above-mentioned inorganic salt used together with the initial condensate is a pore-forming agent that is removed in a later step and used to provide communicating pores to the cured product, such as zinc chloride, sodium phosphate, potassium hydroxide, or potassium sulfide. . Among these, zinc chloride is particularly preferably used. The IP-free material can be used in an amount, for example, 2.5 to 10 times the weight of the initial condensate. If the amount is less than the lower limit, it will be difficult to obtain a porous cured body having communicating pores, and if the amount is more than the upper limit, the mechanical strength of the heat-treated product ultimately obtained will tend to decrease, which is not desirable. The aqueous solution of the initial condensate and inorganic salt varies depending on the type of inorganic salt used, but for example, the aqueous solution of the inorganic salt is 0.1 to 1.
It can be prepared using twice the weight of water. Thus,
For example, an aqueous solution having a viscosity of 100,000 to 100 poise is poured into a suitable mold and heated to a temperature of, for example, 50 to 200°C. During this heating, it is important to suppress evaporation of water in the aqueous solution. That is, it is thought that the initial condensate is heated in an aqueous solution, gradually hardens, and grows into a three-dimensional network structure while separating from zinc chloride and water.

Inorganic salts contained in the cured product can be removed by thoroughly washing the obtained cured product with water, dilute hydrochloric acid, or the like. By drying after removing the inorganic salt, a porous cured condensate with developed communicating pores can be obtained.

The porous cured condensate thus obtained is then heated in a non-oxidizing atmosphere (including under vacuum) to a temperature of 400 to 800°C, preferably to a temperature of 450 to 750°C, particularly preferably to a temperature of 500 to 700°C. Heated and heat treated.

The preferred rate of temperature increase during heat treatment varies somewhat depending on the aromatic condensation polymer used, the extent of its curing treatment, its shape, etc., but in general, a relatively high rate of temperature increase from room temperature to a temperature of about 300°C. For example, a rate of 100° C./hour is also possible. When the temperature reaches 30,000 or higher, the aromatic condensation/thermal decomposition of the rimer starts, and water vapor (H,0),
It is advantageous to raise the temperature at a sufficiently slow rate, since the evolution of hydrogen, methane, and carbon oxides causes the formation of gas.

Such heating and heat treatment of the aromatic condensation polymer is performed in a non-oxidizing atmosphere. Examples of the non-oxidizing atmosphere include nitrogen, argon, helium, neon, carbon dioxide, etc., with nitrogen being preferably used. Such a non-oxidizing atmosphere may be stationary or flowing.

Thus, by the above heating and heat treatment, the atomic ratio of hydrogen atoms/carbon atoms (hereinafter referred to as ll1C ratio) is 0.6 to 0.
The porous organic semiconductor of the present invention has a polyacene skeleton structure of 0.05 to 0.15, preferably 0.5 to 0.15, and has communicating pores with an average pore diameter of 10 μm or less, for example, a continuous pore with an average pore diameter of 0.03 to 10 μm. can get. The porous organic semiconductor of the present invention is insoluble. In addition, the atomic ratio of oxygen atoms/carbon atoms (0/C ratio) is usually 0.06 or less, preferably 0.
．． 03 or less. In addition, X-ray diffraction ((1' u K
According to a), the position of the main peak exists between 20.5 and 255° in 2θ, and in addition to the main peak, there are other broad peaks between 41 and 46°. exists. Also, according to the infrared absorption spectrum, D
(= D t*oo~t*4o / D tsso~t
The absorbance ratio of a4e) is usually 0.5 or less, preferably 0
．． 3 or less.

That is, it is understood that the above-mentioned insoluble and infusible substrate is one in which the polycyclic structure of polyacene-based benzene is evenly and appropriately developed between polyacene-based molecules.

According to the present invention, there is also provided a porous organic semiconductor in which the insoluble and infusible substrate is doped with an electron-donating dopant, an electron-accepting dopant, or both of these dopants.

That is, according to the present invention, (A) a heat-treated product of an aromatic condensation polymer which is a condensation product of an aromatic hydrocarbon compound having a phenolic hydroxyl group and an aldehyde, wherein (a) hydrogen atoms/carbon atoms has a polyacene skeleton structure with an atomic ratio of 0.6 to 0.05, and (b) a porous insoluble and infusible substrate having communicating pores with an average pore diameter of 10 μm or less, and (B) 'el & child donating property. A porous organic semiconductor characterized in that it consists of a dopant and/or an electron-accepting kidopant is provided.

As the electron-donating dopant, a substance that easily releases electrons is used. For example, metals 1A1 of the periodic table such as lithium, sodium, potassium, rubidium or cesium are preferably used.

Similarly, as the electron-donating dopant, tetra(01
~C4 alkyl) ammonium cation/e.g. (CH3
), N or (04H0), N can be used.

Further, as the electron-accepting dopant, a substance that easily accepts electrons is used. For example, fluorine, chlorine, bromine, iodine etc. 7; A8Fg + F Fs
eBF3. BCI-3, EBr, FeC1, etc., or oxides of non-metallic elements such as N2O5; or H,50, BNO
, Nu is preferably an anion derived from an inorganic acid such as HClO4.

As a doping method for such a dopant, essentially the same doping method as conventionally used for polyacetylene or polyphenylene can be used.

For example, when the dopant is an alkali metal, the dopant can be doped by contacting the insoluble and infusible substrate with a molten alkali metal or vapor of the alkali metal, or with an alkali metal naphthalene complex formed in, for example, tetrahydrofuran. Doping can also be carried out by contacting an insoluble and infusible substrate.

When the dopant is a rhodane compound or an oxide of a nonmetallic element, doping can be easily carried out by bringing these gases into contact with an insoluble and infusible substrate.

When the doping agent is an ion removal agent derived from an inorganic acid, it can be carried out by directly coating or impregnating the insoluble and infusible substrate with the inorganic acid.

It is also possible to set the insoluble and infusible substrate as an electrode and electrochemically dope it with an electron-donating dopant such as lithium, Na) or an electron-accepting dopant such as ClO4- or BF4-. .

As mentioned above, since the insoluble and infusible substrate of the present invention is a porous body having communicating pores, it facilitates the diffusion of the gaseous dopant or the dopant in the solution, and enables rapid, large and uniform doping. It has excellent advantages.

The doping agent is generally used so that it is present in the obtained organic semiconductor of the present invention in a ratio of 10 -1 mol or more to the repeating unit of the aromatic condensation polymer.

The organic semiconductor of the present invention thus obtained has an electrical conductivity higher than that of the insoluble and infusible substrate before doping (for example, 10" 1O-st sold-t・a-1),
For example, it increases by several times to 101° compared to the insoluble and infusible substrate before doping. When doped with an electron-donating dopant, an n-type semiconductor is provided, and when doped with an electron-accepting dopant, a p-type semiconductor is provided. According to the present invention, an electron-donating dopant and an electron-accepting dopant can also be used together as be/cents. When these dopants are almost uniformly mixed in the porous organic semiconductor of the present invention, the porous organic semiconductor becomes p-type or n-type depending on which one of the dopants is more present. for example,
If there are many electron-donating dopants, it will be n-type, and if there are many electron-accepting dopants, it will be p-type.
Becomes a mold.

[Action/effect of the invention]

The porous organic semiconductor of the present invention has excellent heat resistance and oxidation resistance, and can be formed into any shape such as a film, plate, or cylinder, making it a highly practical material.

In the porous organic semiconductor of the present invention, the insoluble and infusible substrate having a polyacene skeleton structure has a three-dimensional network structure through communicating pores, so that fluid can freely enter and exit fine details through the communicating pores. easy. The average pore diameter of the communicating pores is fine, 10 μm or less, and the porous body has uniform pore diameters, that is, a sharp pore diameter distribution. In addition, it is possible to obtain porous bodies with an average pore diameter of 0.1 μm, which is extremely fine, to a porous body with an average pore diameter of approximately 10 μm, so that it can be used depending on the purpose.

Utilizing the fine communicating pores of the porous organic semiconductor of the present invention,
It is also possible to rapidly advance the chemical reaction of each layer occurring at the interface, and it is suitably used, for example, as an electrode material for batteries. In addition, since various physical adsorptions occur smoothly and uniformly, combined with the semiconductor properties, adsorption of gases such as H, 0, 0, etc. causes slight changes in electrical conductivity. Therefore, it can be suitably used as a sensor material.

The apparent density of the porous organic semiconductor of the present invention is usually 0.3
~α8f/crA. In other words, the porous organic semiconductor of the present invention includes porous bodies ranging from porous bodies with high porosity to porous bodies with relatively low porosity. Although the appearance of the mechanical strength of a porous body varies depending on the density, for example, even a porous body of the present invention having a strength of 0.5 f/d has sufficient strength for practical use. In addition, since the porous organic semiconductor of the present invention is composed of an insoluble and infusible substrate with a boriacene skeleton structure, it has excellent chemical resistance and has fine interconnected pores, so it can withstand harsh conditions. It is also suitable as a furnace material.

As described above, the porous organic semiconductor of the present invention has excellent heat resistance and oxidation resistance, and has fine interconnected pores, so that electron-accepting or electron-donating dopants can be doped quickly and uniformly. It is an industrially useful material that can be applied in many fields because it is a solid semiconductor and can take any shape such as a film or plate with excellent mechanical strength.

In addition, in this specification, the average pore diameter of the communicating pores is measured and defined as follows.

An electron micrograph is taken of the sample at a magnification of, for example, 1000 to 10,000 times. Draw any straight line on this photo,
If the number of pores intersecting the straight line is n, then the average pore diameter (d
) is calculated by the following formula.

Σli Ga.

Here, li is the length cut by the hole where the straight lines intersect, and 1. Σ li is the sum of the cut lengths for n holes with s=1, and n is the number of holes that intersect the straight line, provided that n takes a value of 10 or more. .

This will be explained in detail below using examples.

Example 1 (1) An aqueous solution containing water-soluble resol (approximately 60% concentration)/zinc chloride/water mixed in a weight ratio of 10/25/4 was formed into a film on a glass plate using a film aggregator. Next, a glass plate was placed over the formed aqueous solution, and the film was cured by heating at a temperature of about 100° C. for 1 hour to prevent moisture from evaporating.

The obtained cured film was washed with dilute hydrochloric acid, then washed with water, and then dried to obtain a cured porous phenol resin film having a thickness of about 200 μm.

The cured phenolic resin porous body was placed in a silicone electrification furnace and heated at a rate of 40°C/hour in a nitrogen stream to a temperature of 60°C.
Heat treatment was performed to 0°C to obtain an insoluble and infusible film-like porous body. When the electrical conductivity of the porous material was measured using the DC 4-terminal method, it was found to be 10-'(Ωa)"l. The apparent density was 0.40 f/-, making it a film with excellent mechanical strength. Elemental analysis of the film revealed that the atomic ratio of hydrogen atoms/carbon atoms was 0.34.The shape of the peak obtained from X-ray diffraction was a pattern based on the polyacene skeleton structure. and 20~ at 2θ
There is a broad main peak around 24°, and 4
A small peak was confirmed around 1 to 466.

Next, in order to observe the state of pores in the film-like semiconductor, an electron micrograph of a cross section of the film was taken.

Shown in Figure 1. As is clear from FIG. 1, it was a porous body with a three-dimensional network structure and fine interconnected pores of 10 μm or less.

(2) Next, a tetrahydrofuran solution of sodium naphthalate was prepared using dehydrated tetrahydrofuran, naphthalene, and metallic sodium. The film semiconductor described above was immersed in this solution in a dry deck and doped at room temperature for about 1 hour. Thereafter, it was washed with dehydrated tetrahydrofuran, and then dried under reduced pressure for about 10 hours. The electrical conductivity of the dry sample is approximately 1o-' (Ω・re)-
It was 1.

Examples 2 to 5 fi+ A cured phenolic resin porous material in the form of a film with a thickness of about 200 μ obtained in the same manner as in Example 1 was heated at a rate of about 30°C/hour under a nitrogen atmosphere in an electric furnace. The temperature was raised to various predetermined temperatures shown in Table 1, and heat treatment was performed. The obtained porous semiconductor film was subjected to elemental analysis and measurement of electrical conductivity. The results are shown in Table 1.

(2) Next, these semiconductor films were placed in a vacuum line, the degree of vacuum was set to about 10"-" Torr, and iodine gas was introduced into the line at room temperature to reduce the doping to about 1.
It lasted 0 minutes. The electrical conductivity at this time is shown in Table 1.

When the distribution state of iodine was examined using an EpMA (electron micro analyzer) on a cross section of these iodine-doped film samples, it was found that the iodine was distributed uniformly.

Iodine doping significantly increased the electrical conductivity.

[Brief explanation of drawings]

Figure 1 shows a cross section of the porous organic semiconductor film of the present invention!
It is a photomicrograph. The length of the bar shown at the bottom right of the photo is 5μ. Procedural amendment (method) July 25, 1985

Claims (1)

[Scope of Claims] 1. A heat-treated product of an aromatic condensation polymer which is a condensation product of an aromatic hydrocarbon compound having a phenolic hydroxyl group and an aldehyde, comprising: (a) an atomic ratio of hydrogen atoms/carbon atoms; is 0.6 to 0.05
A porous organic semiconductor characterized by having a polyacene skeleton structure, and (b) having communicating pores with an average pore diameter of 10 μm or less. 2. The porous organic semiconductor according to claim 1, wherein the aromatic condensation polymer is a condensate of phenol and formaldehyde. 3. The porous organic semiconductor according to claim 1, wherein the atomic ratio of hydrogen atoms/carbon atoms is 0.5 to 0.15. 4. The porous organic semiconductor according to claim 1, having a large number of communicating pores with an average pore diameter of 0.03 to 10 μm. 5. The atomic ratio of oxygen atom (O)/carbon atom (C) is 0.0
The porous organic semiconductor according to claim 1, having a polyacene skeleton structure of 6 or less. 6. The porous organic semiconductor according to claim 1, wherein the heat-treated product exhibits a three-dimensional network structure through a large number of communicating pores. 7. The porous organic semiconductor according to claim 1, wherein the porous organic semiconductor is a film, plate, fiber, or a composite thereof. 8. (A) A heat-treated product of an aromatic condensation polymer which is a condensation product of an aromatic hydrocarbon compound having a phenolic hydroxyl group and an aldehyde, wherein (a) the atomic ratio of hydrogen atoms/carbon atoms is 0. 6～
It has a polyacene skeleton structure of 0.05 and (b
1.) A porous organic semiconductor comprising a porous insoluble and infusible substrate having communicating pores with an average pore diameter of 10 μm or less, and (B) an electron donor dopant and/or an electron acceptor dopant. 9. The porous organic semiconductor according to claim 8, which exhibits electrical conductivity greater than that of the porous insoluble and infusible substrate (A). 10, the electron donating dopant is lithium, sodium,
9. The porous organic semiconductor according to claim 8, which is a Group 1A metal including potassium, rubidium and cesium. 11. The electron-donating dopant is tetra (C_1 to C_3
9. The porous organic semiconductor according to claim 8, which is a lower alkyl) ammonium cation. 12, electron-accepting dopant is AsF_5, PF_5,
The porous organic semiconductor according to claim 8, which is a halide such as BF_3, BCl_3, BBr_3, FeCl_3. 13. The porous organic semiconductor according to claim 8, wherein the electron-accepting dopant is a halogen such as fluorine, chlorine, bromine, or iodine. 14. Electron accepting dopant is SO_3 or N_2
oxides of non-metallic elements such as O_5 or H_2SO_4,
The porous organic semiconductor according to claim 8, which is an anion derived from an inorganic acid such as HNO_3 or HClO_4.