KR20060075656A - Organic light emitting transistor with asymmetric electrode structure and method for fabricating the same - Google Patents

Abstract

The present invention relates to an organic light emitting transistor having an asymmetric electrode structure, and a method of manufacturing the same. A device having a high luminous efficiency by reducing contact resistance between a metal and an organic light emitting material film by forming a source electrode and a drain electrode having an asymmetric work function. There is an effect that can be implemented.

Organic, work function, transistor, light emitting

Description

Organic light emitting transistor having an asymmetric electrode structure and method of manufacturing the same {Organic light emitting transistor with asymmetric electrode structure and method for fabricating the same}             

1A to 1F are cross-sectional views illustrating a manufacturing process of an organic light emitting transistor having an asymmetric electrode structure according to the present invention.

2 is a schematic plan view of a display panel using an organic light emitting transistor according to the present invention.

3 is a schematic plan view of a display panel using an organic light emitting transistor according to the present invention.

<Description of the symbols for the main parts of the drawings>

10 substrate 11 gate electrode

12: insulating film 13a, 13b, 13c, 13d: source electrode

14a, 14b, 14c, and 14d: drain electrodes 15, 15a, 15b, and 15c: organic light emitting material film

16: protective film 21, 22, 23: organic light emitting material

31,32,33: Color Filter

The present invention relates to an organic light emitting transistor having an asymmetric electrode structure and a method of manufacturing the same, and more particularly, to form a source electrode and a drain electrode having an asymmetric work function, thereby reducing contact resistance between the metal and the organic light emitting material film, thereby providing high emission. The present invention relates to an organic light emitting transistor having an asymmetric electrode structure capable of implementing a device having efficiency and a method of manufacturing the same.

Currently, organic light emitting diodes that are developed and produced in a display form are classified into a passive matrix that does not include an active element and an active matrix that includes an active element.

Since the passive method does not have a separate active element, it is very difficult to obtain a high resolution and high quality image. Therefore, the passive method is being developed around an active organic EL including a thin film transistor (TFT).

However, unlike the conventional liquid crystal display (LCD), the organic EL is not a voltage driving method but a current driving method, so a separate circuit for controlling current is required.

At present, the developed method includes a driving circuit including two transistors and one capacitor, a driving circuit including four transistors and two capacitors, and the like. However, if two or four transistors are included in the configuration of one pixel, the light emitting part becomes very small.

In the conventional LCD, since only one transistor is required per pixel, this problem did not work. However, in the organic EL, this problem is large because a single pixel must be integrated. have.

Recently, in order to increase the emission area, Top Emission organic EL has been introduced, but in this case, loss of luminance or efficiency is caused due to the low transmittance of the metal electrode.

On the other hand, an organic light emitting transistor (OLET; Organic Light Emitting Transistor) has been proposed to maximize the light emitting area while utilizing the strength of the organic EL. The organic light emitting transistor generates light using a light emitting layer in the form of a diode, while OLET emits light using three electrodes (gate, source, and drain), and also serves as a switching device.

With this structure, the light intensity can be controlled by the gate voltage and the source-drain voltage, so that a high resolution and high quality screen can be obtained without a separate active driving device.

In addition, since only one transistor is used, the area that actually emits light is large, so that excellent characteristics can be obtained in terms of luminance and efficiency.

The OLET structure known to date uses gold, silver, platinum, etc., which have a high work function as a source-drain electrode. When the source-drain electrode is used as a material having the same work function, the drain electrode and the organic semiconductor are used. Schottky contact is generated between them, resulting in a very large contact resistance, resulting in low luminous efficiency.

However, when a material having a low work function is used as the drain electrode, the contact resistance can be effectively lowered and the luminous efficiency can be increased.

Currently, organic light emitting transistors, which are in the early stages of development worldwide, mainly use gold (Au) having a high work function (above 5 eV) as source and drain electrode materials due to the high OOCupied Molecular Orbital (HOMO).

In this case, due to the high contact resistance, a high energy barrier is formed when electrons move from the drain electrode to the organic material, and the light emitting portion is also limited in part to the drain electrode direction.

Research and development to date has only shown the possibility that this structure can be developed into a new display form, and there are still many areas to be improved.

Accordingly, the present invention has been made to solve the problems described above, by forming a source electrode and a drain electrode having an asymmetric work function, it is possible to implement a device having a high luminous efficiency by reducing the contact resistance to the metal and organic light emitting material film An object of the present invention is to provide an organic light emitting transistor having an asymmetric electrode structure and a method of manufacturing the same.

A preferred aspect for achieving the above objects of the present invention is a substrate;                         

A gate electrode formed at an upper center of the substrate;

An insulating film surrounding the gate electrode and formed on the substrate;

A plurality of source electrodes spaced apart from each other on the insulating film;

A plurality of drain electrodes disposed between the source electrodes and formed on the insulating film;

An organic light emitting material layer surrounding the source and drain electrodes and formed on the insulating layer;

An organic light emitting transistor having an asymmetric electrode structure surrounding the organic light emitting material layer and including a protective film formed on the insulating layer is provided.

Another preferred aspect for achieving the above object of the present invention comprises the steps of forming a gate electrode in the center of the upper substrate;

Forming an insulating layer on the substrate while surrounding the gate electrode;

Forming a plurality of source electrodes spaced apart from each other on the insulating film;

Forming an upper portion of the insulating layer such that a plurality of drain electrodes are positioned between each of the source electrodes;

Surrounding the source and drain electrodes, forming an organic light emitting material layer on the insulating layer;

A method of manufacturing an organic light emitting transistor having an asymmetric electrode structure including covering the organic light emitting material layer and forming a protective film on the insulating layer is provided.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

1A to 1F are cross-sectional views illustrating a manufacturing process of an organic light emitting transistor having an asymmetric electrode structure according to the present invention. First, a gate electrode 11 is formed in an upper center of a substrate 10 (FIG. 1A).

The substrate 10 may be any one of a silicon wafer, a glass substrate, a polymer plastic substrate, and a paper substrate.

The gate electrode 11 is formed of a metal or a conductive polymer.

That is, Al, Ag, or the like having high reflectance may be used as the gate electrode 11 material, and when using a transparent electrode such as indium tin oxide (ITO), double-sided light emission may be performed.

After that, the insulating layer 12 is formed on the substrate 10 while surrounding the gate electrode 11 (FIG. 1B).

Here, the insulating film 12 is formed of an inorganic material or an organic material.

Then, a plurality of source electrodes 13a, 13b, 13c, and 13d spaced apart from each other are formed on the insulating film 12 (FIG. 1C).

Subsequently, a plurality of drain electrodes 14a, 14b, 14c, and 14d are disposed between the source electrodes 13a, 13b, 13c, and 13d, respectively, to be formed on the insulating layer 12 (FIG. 1D).

That is, the source electrodes 13a, 13b, 13c, and 13d and the drain electrodes 14a, 14b, 14c, and 14d are alternately positioned.

In this case, the source electrodes 13a, 13b, 13c, and 13d may be formed of any one of indium tin oxide (ITO), Au, Cr, Pt, Cu, and Zn having a work function of 4.2 to 5.5 eV.

The drain electrodes 14a, 14b, 14c, and 14d are formed of any one of Ca, Al, Sm, and Yb having a work function of 2.0 to 4.0 eV.

In addition, the channel length, which is an interval between the source electrodes 13a, 13b, 13c, and 13d and the drain electrodes 14a, 14b, 14c, and 14d, must be within a range of 50 to 5000 nm to obtain efficient characteristics. have.

Subsequently, the source electrodes 13a, 13b, 13c, and 13d and the drain electrodes 14a, 14b, 14c, and 14d are wrapped to form an organic light emitting material film 15 on the insulating film 12. 1e)

The organic light emitting material layer 15 is formed by one of vacuum evaporation, spin coating, dip coating, ink-jet printing, and stamping. do.

The thickness T of the organic light emitting material is suitably 30 to 15000 nm.

Finally, the passivation layer 16 is formed on the insulating layer 12 to surround the organic light emitting material layer 15 (FIG. 1F).

An organic light emitting transistor having an asymmetric electrode structure manufactured by the above-described process includes: a substrate 10; A gate electrode 11 formed at the center of the upper portion of the substrate 10; An insulating film 12 surrounding the gate electrode 11 and formed on the substrate 10; A plurality of source electrodes 13a, 13b, 13c, and 13d formed spaced apart from each other on the insulating film 12; A plurality of drain electrodes 14a, 14b, 14c, and 14d respectively positioned between the source electrodes 13a, 13b, 13c, and 13d and formed on the insulating layer 12; An organic light emitting material film 15 surrounding the source electrodes 13a, 13b, 13c, and 13d and the drain electrodes 14a, 14b, 14c, and 14d and formed on the insulating film 12; The organic light emitting material layer 15 may include a passivation layer 16 formed on the insulating layer 12.

The organic light emitting material layer 15 may be any one of red, green, blue, and white light emitting materials.

The organic light emitting transistor applies a negative voltage to a gate electrode, a ground voltage to a drain electrode, and a positive voltage to a source electrode, and provides carriers (electrons and electrons) in a channel region corresponding to an organic light emitting material film between the source electrode and the drain electrode. Holes) are recombined to emit light and operate.

FIG. 2 is a schematic plan view of a display panel using an organic light emitting transistor according to the present invention. In order to implement a display panel using an organic light emitting transistor, a plurality of substrates may be formed on the substrate 10 as in the process of FIGS. 1A to 1F described above. The organic light emitting transistors are formed, and red, green, and blue organic light emitting materials 21, 22, and 23 are applied to each of the organic light emitting transistors to form a plurality of pixels of the display including R, G, and B. do.

FIG. 3 is a schematic plan view of a display panel using an organic light emitting transistor according to the present invention. If the organic light emitting material layers 15a, 15b, and 15c are white light emitting materials, the organic light emitting transistors may be disposed on the passivation layer 16 of each organic light emitting transistor. Color filters 31, 32, and 33 of R, G, and B are attached to implement a display panel.

As described above, the present invention has an excellent effect of forming a device having a high luminous efficiency by reducing the contact resistance between the metal and the organic light emitting material film by forming a source electrode and a drain electrode having an asymmetric work function.

Although the invention has been described in detail only with respect to specific examples, it will be apparent to those skilled in the art that various modifications and variations are possible within the spirit of the invention, and such modifications and variations belong to the appended claims.

Claims (14)

A substrate; A gate electrode formed at an upper center of the substrate; An insulating film surrounding the gate electrode and formed on the substrate; A plurality of source electrodes spaced apart from each other on the insulating film; A plurality of drain electrodes disposed between the source electrodes and formed on the insulating film; An organic light emitting material layer surrounding the source and drain electrodes and formed on the insulating layer; And an asymmetric electrode structure surrounding the organic light emitting material layer and including a protective film formed on the insulating layer. The method of claim 1, The source electrode, An organic light emitting transistor having an asymmetric electrode structure, characterized in that the work function is larger than the drain electrodes. The method of claim 2, The work function of the source electrodes is 4.2 ~ 5.5eV, The work function of the drain electrodes is an organic light emitting transistor having an asymmetric electrode structure, characterized in that 2.0 ~ 4.0eV. The method of claim 2 or 3, The source electrodes are formed of any one of indium tin oxide (ITO), Au, Cr, Pt, Cu, and Zn, The drain electrodes are organic light emitting transistors having an asymmetric electrode structure, characterized in that formed of any one of Ca, Al, Sm and Yb. The method according to any one of claims 1 to 3, The organic light emitting material film, An organic light emitting transistor having an asymmetric electrode structure, characterized in that any one of red, green, blue and white light emitting material. The method according to any one of claims 1 to 3, The substrate, An organic light emitting transistor having an asymmetric electrode structure, which is any one of a silicon wafer, a glass substrate, a polymer plastic substrate, and a paper substrate. The method according to any one of claims 1 to 3, The gate electrode is an organic light emitting transistor having an asymmetric electrode structure, characterized in that formed of a metal or a conductive polymer. The method according to any one of claims 1 to 3, The length of the channel, which is an interval between the source and drain electrodes, is An organic light emitting transistor having an asymmetric electrode structure, characterized in that 50 ~ 5000nm. The method according to any one of claims 1 to 3, The organic light emitting transistor having an asymmetric electrode structure, characterized in that the thickness (T) of the organic light emitting material is 30 ~ 15000nm. Forming a gate electrode at the center of the upper substrate; Forming an insulating layer on the substrate while surrounding the gate electrode; Forming a plurality of source electrodes spaced apart from each other on the insulating film; Forming an upper portion of the insulating layer such that a plurality of drain electrodes are positioned between each of the source electrodes; Surrounding the source and drain electrodes, forming an organic light emitting material layer on the insulating layer; A method of manufacturing an organic light emitting transistor having an asymmetric electrode structure including surrounding the organic light emitting material layer and forming a passivation layer on the insulating layer. The method of claim 10, The source electrodes, A method of manufacturing an organic light emitting transistor having an asymmetric electrode structure, characterized in that the work function is larger than the drain electrodes. The method of claim 11, The work function of the source electrodes is 4.2 ~ 5.5eV, The work function of the drain electrodes is an organic light emitting transistor having an asymmetric electrode structure, characterized in that 2.0 ~ 4.0eV. The method according to claim 11 or 12, The source electrodes are formed of any one of indium tin oxide (ITO), Au, Cr, Pt, Cu, and Zn, The drain electrodes are organic light emitting transistors having an asymmetric electrode structure, characterized in that formed of any one of Ca, Al, Sm and Yb. The method of claim 10, The organic light emitting material film, An asymmetric electrode structure is formed by one of vacuum evaporation, spin coating, dip coating, ink-jet printing, and stamping. The method of manufacturing an organic light emitting transistor.

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