KR101390293B1 - Organic light emitting diode using sioc hole blocking layer - Google Patents

Abstract

An organic light emitting diode (OLED) having an outstanding light emitting efficiency by preventing a hole overflow is disclosed. For the OLED according to the present invention, a light emitting layer is formed between an electron providing layer and a hole providing layer, and the electron providing layer, the hole providing layer, and the light emitting layer are formed by including organic materials. A hole blocking layer for preventing holes supplied by the hole providing layer from being overflown to the electron providing layer is formed between the light emitting layer and the electron providing layer, wherein the hole blocking layer is formed with a material including SiOC. [Reference numerals] (110) Hole providing layer; (120) Light emitting layer; (130) Electron providing layer; (140a) Positive electrode; (140b) Negative electrode

Description

OLED using SiOC hole blocking layer {ORGANIC LIGHT EMITTING DIODE USING SiOC HOLE BLOCKING LAYER}

The present invention relates to an organic light emitting diode (OLED), and more particularly to an OLED capable of preventing hole overflow by using a silicon oxycarbide (SiOC) hole blocking layer.

Organic Light Emitting Diodes (OLEDs) can be driven at low voltages, can be implemented thinly, and have fast response speeds.

1 schematically shows a general OLED.

Referring to FIG. 1, an OLED typically includes a hole providing layer 110, a light emitting layer 120, and an electron providing layer 130, and each of these layers is formed of an organic material.

The light emitting layer 120 is formed of a fluorescent organic material, and when the holes supplied from the hole providing layer 110 and electrons supplied from the electron providing layer 130 recombine in the light emitting layer 120, the fluorescent organic material is driven to emit light.

Meanwhile, in the OLED illustrated in FIG. 1, holes supplied from the hole providing layer 110 do not recombine with electrons in the light emitting layer 120, and there is a problem of overflowing to the electron providing layer 130.

This hole overflow may be a factor that inhibits the luminous efficiency by preventing electron-hole recombination in the emission layer 120.

In order to solve this problem, for example, a method of introducing a hole blocking layer into a material such as Balq, BCP, or adding a hole blocking role to the electron transport layer is proposed. However, in the case of the hole overflow prevention methods, there is another problem that impedes electron movement.

Prior arts related to the present invention include an organic light emitting diode device disclosed in Korean Patent Laid-Open Publication No. 10-2008-0074518 (published on Aug. 13, 2008) and a method of manufacturing the same.

An object of the present invention is to provide an OLED that can prevent the holes supplied from the hole providing layer from overflowing to the electron providing layer, thereby improving luminous efficiency.

OLED according to an embodiment of the present invention for achieving the above object is a light emitting layer is formed between the electron providing layer and the hole providing layer, the electron providing layer, the hole providing layer and the light emitting layer is formed including an organic material, the light emitting layer Between the and the electron providing layer, a hole blocking layer is formed to prevent the holes supplied from the hole providing layer from overflowing to the electron providing layer, the hole blocking layer is formed of a material containing SiOC It features.

In this case, the SiOC of the hole blocking layer preferably contains 1 to 15 mol% of carbon (C) and 100 mol% of silicon (Si), oxygen (O) and carbon (C), and carbon (C) is silicon ( More preferably, 3 to 10 mol% of 100 mol% of Si, oxygen (O), and carbon (C) are contained, and carbon (C) is 100 mol% of silicon (Si), oxygen (O), and carbon (C). Most preferably, it is contained in 3 to 5 mol% of.

In addition, the SiOC of the hole blocking layer may include oxygen (O) as 50 to 200 mol% of 100 mol% of silicon (Si).

The OLED may further include a cathode electrically connected to the electron providing layer; And an anode electrically connected to the hole providing layer.

The OLED according to the present invention forms an SiOC hole blocking layer between the light emitting layer and the electron providing layer, thereby preventing the hole from overflowing to the electron providing layer without inhibiting electron mobility from the electron providing layer to the light emitting layer.

Through this, recombination of electrons and holes in the light emitting layer can be performed more smoothly, thereby improving the light emitting efficiency.

1 schematically shows a conventional OLED.
2 schematically shows an OLED according to an embodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and how to accomplish them, will become apparent by reference to the embodiments described in detail below with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various forms, and only the present embodiments are intended to complete the disclosure of the present invention, and those skilled in the art to which the present invention pertains. It is provided to fully inform the scope of the invention, and the invention is defined only by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

Hereinafter, an OLED using an SiOC hole blocking layer according to the present invention will be described in detail with reference to the accompanying drawings.

2 schematically shows an OLED according to an embodiment of the invention.

Referring to FIG. 2, the OLED according to the present invention includes a hole providing layer 110, a light emitting layer 120, and an electron providing layer 130, similar to the OLED illustrated in FIG. 1, and each of these layers is formed of an organic material. Is formed.

The hole providing layer 110 may be a single layer structure or a hole injecting layer / hole transporting layer stacking structure. Similarly, the electron donating layer 130 may be a single layer structure or an electron injecting layer / electron transporting layer stacking structure.

The hole providing layer 110, the light emitting layer 120, and the electron donating layer 130 may be formed on a glass substrate, or may be formed on a polymer substrate to secure a flexible property.

The light emitting layer 120 is formed of a fluorescent organic material. When the holes supplied from the hole providing layer 110 and the electrons supplied from the electron providing layer 130 are recombined in the light emitting layer 120, the fluorescent organic material is driven by light.

In addition, the OLED according to the present invention, in order to inject holes in the hole providing layer 110, to inject electrons into the anode 140a and the electron providing layer 130 electrically connected to the hole providing layer 110. The cathode may further include a cathode 140b electrically connected to the electron providing layer 130.

In the OLED according to the present invention, a hole blocking layer 210 is formed between the light emitting layer 120 and the electron providing layer 130. The hole blocking layer 210 serves to prevent holes supplied from the hole providing layer 110 from overflowing into the electron providing layer 130. As described above, when the hole blocking layer 210 is not formed, the electron-hole recombination in the emission layer 120 is not smoothly performed, and thus the luminous efficiency may be lowered. ) And the hole blocking layer 210 between the light emitting layer 120.

 At this time, in the present invention, the hole blocking layer 210 is formed of a material including silicon oxycarbide (SiOC).

In the case of SiOC, the Poole-Frenkel junction is formed so that the potential barrier increases abruptly at the interface, while the width of the depletion layer becomes relatively thin, tunneling occurs and electrons are smoothly transported, Which is a nonlinear rectifying bondable material. When forming the hole blocking layer 210 with SiOC, electrons are allowed to pass from the electron donating layer 130 to the light emitting layer 120 through tunneling, but the holes can not pass through the high potential barrier, It is possible to effectively prevent overflow of the holes without hindering the electron mobility by causing the electrons and holes to be emitted and eliminated by recombination.

The SiOC may be formed by partially including carbon (C) in silicon oxide (SiOx). SiOC can be formed by various methods such as chemical vapor deposition (CVD) and physical vapor deposition (PVD).

At this time, the SiOC is preferably carbon (C) is contained in 1 ~ 15mol% of silicon (Si), oxygen (O) and 100% of the total carbon (C), more preferably contained in 3 ~ 10mol% Most preferably, 3 to 5 mol%.

If the carbon content is less than 1 mol%, the hole blocking effect is insufficient. On the contrary, when the carbon exceeds 15 mol%, the leakage current is increased, and in particular, pores are formed, resulting in a decrease in film uniformity and a decrease in strength.

Table 1 shows the luminous efficiency according to the carbon content when the SiOC hole blocking layer having a thickness of 20 nm is applied. The luminous efficiency is expressed as a relative value when the light output when the 20 nm thick Balq hole blocking layer is applied is set to 100%.

[Table 1]

Referring to Table 1, when the SiOC hole blocking layer is applied, the luminous efficiency is relatively high as compared with the conventional Balq hole blocking layer. In addition, when the carbon content is 3 ~ 10mol%, the luminous efficiency was relatively higher. In particular, when the carbon content of 3 ~ 5mol%, the luminous efficiency was found to be significantly high, it can be seen that the carbon content of 3 ~ 5mol% is the most preferable.

In addition, the SiOC of the hole blocking layer may include oxygen (O) as 50 to 200 mol% of 100 mol% of silicon (Si). When the oxygen content is less than 50 mol%, the hole blocking property may be lowered. In contrast, it is very difficult for the oxygen (O) content to exceed 200 mol%. Such oxygen (O) content can be controlled by adjusting the oxygen supply amount at the time of forming the SiOC film.

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On the other hand, the thickness of the hole blocking layer 210 may be about 50 nm, but the thickness of the hole blocking layer 210 may not be a large variable in the present invention. The reason for this is that electron transport corresponds to transport by tunneling in the present invention. That is, in the case of the transmission effect by trapping, if the thickness of the hole blocking layer becomes thick, electron mobility may decrease, but transmission by tunneling does not reduce electron mobility regardless of thickness, but rather by tunneling effect. Electron mobility can be higher.

Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. These changes and modifications may be made without departing from the scope of the present invention. Accordingly, the scope of the present invention should be determined by the following claims.

110: electron providing layer 120: light emitting layer
130: hole providing layer 140a: cathode
140b: anode 210: SiOC hole blocking layer

Claims (5)

A light emitting layer is formed between the electron providing layer and the hole providing layer, wherein the electron providing layer, the hole providing layer, and the light emitting layer include an organic material,
A hole blocking layer is formed between the light emitting layer and the electron providing layer to prevent holes supplied from the hole providing layer from overflowing to the electron providing layer, wherein the hole blocking layer includes SiOC. OLED, characterized in that formed of a material.
The method of claim 1,
SiOC of the hole blocking layer
OLED (C) is characterized in that the silicon (Si), oxygen (O) and carbon (C) is characterized in that 1 to 15mol% of the total 100mol%.
The method of claim 1,
SiOC of the hole blocking layer
OLED (C) is characterized in that the silicon (Si), oxygen (O) and carbon (C) is characterized in that 3 to 5 mol% of the total 100 mol%.
The method of claim 1,
SiOC of the hole blocking layer
OLED (O) is characterized in that it comprises 50 to 200 mol% of 100 mol% of silicon (Si).
The method of claim 1,
The OLED
A cathode electrically connected to the electron providing layer; And
And an anode electrically connected to the hole providing layer.

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