Organic functional element and method for manufacturing same

Abstract

The object of the invention is to provide a highly reliable organic functional element such as an organic EL element or an organic semiconductor element exemplified by an organic TFT element which can be manufactured without requiring a vapor deposition process for forming an electrode on an organic material layer. Consequently, such an organic functional element can be large-sized easily and produced at lower cost. In addition, no damage is caused to the organic material layer during formation of the electrode, and the organic functional element is not affected by environmental changes. Also disclosed is a method for manufacturing such an organic functional element. To attain the above-mentioned object, the present invention provides an organic functional element comprising at least a plurality of electrodes and an organic material layer which is characterized in that at least one of the electrodes is composed of a metal having a melting point not higher than a temperature that is higher by 30° C. than the glass transition temperature of the organic material layer.

Description

TECHNICAL FIELD [0001] The present invention relates to an organic functional element, particularly an organic semiconductor element, an organic thin film transistor element (hereinafter, “thin film transistor” is referred to as “TFT”), an organic electroluminescence element (hereinafter, “electroluminescence” is referred to as “EL”), and a method for manufacturing the same. BACKGROUND ART [0002] In recent years, flat display apparatus (flat displays) are used in many fields and places, and have increasing importance with the progress of information technology. A typical example of the flat display at present is a liquid crystal display (also referred to as “LCD”), and as flat displays based on a displaying principle different from that of the LCD: an organic EL display, an inorganic EL display, a plasma display panel (also referred to as “PDP”), a light emitting diode display apparatus (also referred to as “LED”), a vacuum fluorescent display apparatus (also referred to as “VFD”), ...

AI Technical Summary

Benefits of technology

[0028] The present invention was achieved in view of the above-mentioned problems. The object of the invention is to provide a highly reliable organic functional element such as an organic EL element or an organic semiconductor element exemplified by an organic TFT element which can be manufactured without requiring a vapor deposition process for forming an electrode on an organic material layer. Consequently, such an organic functional element can be large-sized easily and produced at lower cost. In addition, no damage is caused to the organic material layer during formation of the electrode, and the organic functional element is not affected by environmental changes. Also disclosed is a method for manufacturing such an organic functional element. MEANS FOR SOLVING THE PROBLEM

Problems solved by technology

In the light receiving type display such as the LCD, the backlight is always lighted regardless of the mode of displayed information, thus consuming almost the same power as in the full displaying state.

This problem, on the other hand, hardly occurs in the self light emitting type display.

Among the methods described above, the method of vapor deposition of the low-molecular material with a mask is limited because of difficulty in large-sizing of the vacuum apparatus and the vapor deposition mask, so there is a problem of difficulty in large-sizing and in preparation of a large number of sheets by using large substrates.

This is not problematic for trial manufacture in the stage of development, but indicates poor competitiveness in the market in respect of tact and cost in the full-scale manufacturing stage.

In the manufacturing method described above, however, since the cathode is formed by vapor deposition, a large-scale vacuum apparatus is necessary only for this step, and for vacuum drawing, the production tact is delayed.

As a result, there is a problem that the characteristics of the organic EL material that can be coated to form a film cannot be fully utilized.

That is, when the melting point of the metal serving as an electrode is high, the high-temperature stability of the organic material layer at the time of forming the electrode is problematic, and a heating temperature significantly higher than the glass transition temperature of the organic material layer causes a problem of seriously affecting the organic material layer.

On the other hand, when the melting point of the metal serving as an electrode is low, the storage stability thereof as a functional element becomes problematic.

In an environment such as inside of automobile in summer, for example, the temperature inside the automobile is significantly increased, and when the organic EL element is used as a display apparatus where a low-melting metal serves as an electrode, there is a problem that the electrode is melted due to high temperatures to break the apparatus.

The alkali metal and alkaline earth metal in organic EL elements described in the patent documents 4, 5 and 6 are strongly oxidative, combustible and unstable in the air and are thus difficult to handle, so they can be formed into a film only under vacuum by vapor deposition, or the like.

This is because there is a problem that the electrode cannot be produced without using the vacuum vapor deposition process since the melting point of the metal used is high.

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