JPH0381282B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for processing organic semiconductor materials.

Since this type of material can be formed into any shape in principle, it is expected to be applied in various fields, such as as a temperature-sensitive resistor material, a solid electrolyte material for solid electrolytic capacitors, a solid electrolyte material for batteries, etc.

In particular, the present invention provides a treatment method suitable for applying TCNQ salt to materials other than solid electrolyte materials for solid electrolytic capacitors, such as temperature-sensitive resistor materials and solid electrolyte materials for batteries as described above. be.

Among organic semiconductors, TCNQ salt is famous as an organic semiconductor with particularly high conductivity. Here
TCNQ is an abbreviation for 7,7,8,8,tetracyanoquinodimethane, and the properties of TCNQ and TCNQ salts can be found in J.Am.Chem.Soc., Vol.84, pp3377
~3387 (1962).

However, TCNQ salt is usually a powdery crystal, and although the crystal itself exhibits high electrical conductivity, it is difficult to mold it because of its powdery state.

Conventionally proposed methods for forming TCNQ salt can be classified into the following three types.

(1) In solvents such as DMF (dimethylformamide)
A method in which a solution containing TCNQ salt is applied to a substrate of a specified shape, and then dried to remove the solvent by scattering.

(2) A method in which fine crystals of TCNQ salt are made using a ball mill or the like and dispersed in alcohol, etc., and then applied to the above substrate and dried.

(3) A method of vacuum evaporating TCNQ salt onto the above substrate.

In method (1) above, DMF, which has high solubility for TCNQ salt, is used as a solvent, and such a solvent is
Even when heated to ℃, its solubility is limited to 10%. This means that it is necessary to apply and dry the TCNQ salt many times to apply the necessary thickness to a flat substrate, or to apply the TCNQ salt to a porous substrate with sufficient impregnation. are doing. Furthermore, the substrate coated with the solution is left at high temperatures each time it is dried, but at this time the TCNQ salt changes in quality to a greater or lesser extent, leading to deterioration of its conductivity. In addition, since the TCNQ salt deposited on the substrate in this way consists of fine crystals, a coagulating resin such as polyvinylpyrrolidone is actually added to the coating solution to strengthen the adhesion strength of the fine crystals. However, since such a coagulating resin is an electrical insulator, the conductivity of the TCNQ salt is even lower (approximately 800 Ωcm [at 25°C]), coupled with the deterioration of the conductivity described above.
Nasu.

In method (2) above, there is a limit to the miniaturization of the TCNQ salt, and the adhesion strength to the substrate is particularly weak, so the TCNQ salt may peel off from the substrate. This enhancement of adhesive strength can be improved to some extent by employing a coagulating resin as described above, but this also results in a decrease in the electrical conductivity of the TCNQ salt. Furthermore, since a dispersion solution of fine crystals made of TCNQ salt is used, the impregnation rate into a porous substrate is particularly poor, and even if an ultrasonic diffusion impregnation method is used, the impregnation rate is low.

In the method (3) above, not only is the vacuum evaporation work complicated, but it is also completely unsuitable for attachment to porous substrates.

The present invention provides a completely new method for processing organic semiconductor materials, more specifically, a method for producing a liquid consisting only of TCNQ salt, cooling and solidifying the liquid, and applying the liquid to a substrate of a predetermined shape. By cooling and solidifying in contact, any shape can be formed.
A semiconductor material consisting of TCNQ salt can be obtained.

The most practical way to obtain a liquid consisting only of TCNQ salt is to liquefy the powdered TCNQ salt in its original form by heating and melting it. However, simply heating and melting the TCNQ salt thermally decomposes the TCNQ salt and turns it into almost an electrical insulator.

The present invention provides certain TCNQ salts, specifically:
N-(isopropyl)-quinolinium and N-(n-
Even if the TCNQ salt of quinolinium (propyl)-quinolinium is heated and melted, it takes a short time to thermally decompose, but there is enough time for the adhesion process. This is based on the completely new finding that it is possible to obtain TCNQ salts that retain their electrical conductivity.

That is, N-(isopropyl)-quinolinium and N-(n-propyl)-quinolinium TCNQ salt melts at about 250℃, but after melting about 1
If it is cooled and solidified within minutes, preferably within about 20 seconds, it will crystallize again and exhibit a high electrical conductivity of 20 to 30 Ωcm (25°C). At this time, it is preferable to maintain the TCNQ salt at a temperature of about 270° C. or lower from when it is liquefied until it is cooled and solidified. At a temperature of about 270℃ or more, or for about 1 minute or more at a temperature below that temperature,
In the worst case scenario, if the above TCNQ salt is kept in a liquid state for more than 20 seconds, the TCNQ salt will smoke violently.
Almost becomes an electrical insulator.

The TCNQ salt formed according to the present invention is not a collection of fine crystals as in the case of the conventional methods (1) and (2), but is almost in an amorphous state.

According to the present invention, it is the same as attaching TCNQ salt to the substrate using a solution containing 100% TCNQ salt, so it is completely different from the conventional method (1) described above, and almost all the attaching work is done in one time. , it is possible to form the required amount of TCNQ salt even when the substrate is not only foil-like but also porous, which not only improves mass productivity but also overcomes the conventional drawback that TCNQ salt deteriorates every time it is dried. be done. Furthermore, according to the present invention,
Because the shaped TCNQ salt is close to an amorphous state,
The adhesion force to the substrate is sufficiently large, so that there is no need to use a conventional coagulating resin, and an undesired decrease in the conductivity of the TCNQ salt can be avoided.

An example of the processing method of the present invention will be explained below. First, a TCNQ salt of N-(isopropyl)-quinolinium is prepared. The preparation of such TCNQ salt itself is described in the above-mentioned document J.Am.Chem.Soc., Vol.84, pp3374-3387.
(1962), but to put it simply, isopropyl iodide and quinoline are reacted to create N-(isopropyl)-quinolinium iodide, and TCNQ is dissolved in acetonitrile. By reacting these in approximately equimolar amounts, powdered crystalline N-(isopropyl)-
The TCNQ salt of quinolinium is produced. Hereinafter, this salt will be simply referred to as TCNQ salt.

On the other hand, an example in which a porous substrate is used as an example of a base will be described. As shown in FIG. 1, a porous base 1 as a film-forming metal having an oxide film is prepared by anodizing a sintered body of aluminum powder.

After the above preparation, the process to be executed is to
It is deposited by impregnation with a solid electrolyte consisting of TCNQ salt. That is, the prepared powder
As shown in FIG. 2, a TCNQ salt bath 3 is provided in which TCNQ salt is stored under moderate pressure in an aluminum container 2 and melted and liquefied by heating the container 2. The temperature of this bath is maintained below 270°C. still,
Pressurization when storing TCNQ salt in the aluminum container 2 is not essential.

In the following process, as shown in Figure 3, the temperature is preliminarily heated to 260℃.
The base 1 heated and maintained at ~270°C is immersed in the TCNQ salt bath 3, immediately pulled up, and left at room temperature. This allows the porous base 1 to be impregnated with
The TCNQ salt solidifies on cooling and becomes the desired solid electrolyte. The time required from liquefaction to cooling solidification of the TCNQ salt is about 10 seconds.

Next, as an example of the present invention, a case of manufacturing a temperature-sensitive resistor will be described. First, as shown in FIG. 4, a glass substrate 10 is prepared, and the substrate is immersed in the TCNQ salt bath 3 in the same manner as in FIG. 2, immediately taken out, and left at room temperature. As a result, as shown in Figure 5,
An organic semiconductor film 11 made of TCNQ salt is attached around the substrate 10. The holding temperature of the TCNQ salt bath 3 and the time from liquefaction to cooling solidification of the TCNQ salt are the same as in the above treatment example.

Next, as shown in FIG. 6, the substrate 10 having the organic semiconductor film 11 is fixed onto a resin substrate 13 having an ordinary copper printed circuit 12, and both ends of the organic semiconductor film 11 and the copper printed circuit 12 are made conductive. They are bonded with paint 14, and the desired temperature-sensitive resistor is completed. FIG. 7 shows the temperature characteristics of such a resistor.

As is clear from the above description, according to the present invention, an organic semiconductor made of TCNQ salt can be easily attached to a substrate such as a temperature-sensitive resistor of a predetermined shape, and the deterioration of TCNQ salt can be avoided during the attachment process. There is almost no accompanying

[Brief explanation of drawings]

1 to 3 are step-by-step diagrams for explaining the present invention, with FIG. 1 being a side view, and FIGS. 2 and 3 being sectional views. FIG. 4 to FIG. 6 are cross-sectional views showing each process according to an embodiment of the present invention, and FIG. 7 is a temperature characteristic diagram. 3...TCNQ salt bath, 11...Organic semiconductor film.

Claims (1)

[Scope of Claims] 1 (a) Storing TCNQ salt that can be melted by heating in a container and heating the TCNQ salt to melt and liquefy it; (b) Pyrolysis in which the TCNQ salt is thermally decomposed above its melting point. (c) immersing a substrate in the TCNQ salt bath and depositing the salt on the substrate within a period of time until the TCNQ salt thermally decomposes;
A method for processing an organic semiconductor material, characterized by cooling and solidifying TCNQ salt.