KR20140087661A - Oganic electro-luminesence display panel and manufactucring method of the same - Google Patents

Abstract

The present invention relates to an organic light emitting display panel capable of improving red and green color features and a manufacturing method thereof. The organic light emitting display panel according to the present invention includes a thin film transistor which is formed on a substrate, a first electrode which is connected to the thin film transistor, a bank insulation layer which has a bank hole to expose the first electrode, a hole injection layer and a hole transport layer which are successively laminated in each bank hole divided by the bank insulation layer, a red light emitting layer which is formed on the hole transport layer in the bank hole and emits red light, a green light emitting layer which is formed on the hole transport layer in the bank hole and emits green light, a blue host layer which is formed on the front side of the substrate with the red light emitting layer and the green light emitting layer, a blue light emitting layer which is formed on the front side of the blue host layer, and an electron transport layer and a second electrode which are successively formed on the front side of the blue light emitting layer.

Description

TECHNICAL FIELD [0001] The present invention relates to an organic electroluminescence display panel and an organic electroluminescent display panel,

The present invention relates to an organic light emitting display panel and a method of manufacturing the same, and more particularly, to an organic light emitting display panel capable of improving red and green color characteristics and a method of manufacturing the same.

The image display device that realizes various information on the screen is a core technology of the information communication age and it is becoming thinner, lighter, more portable and higher performance. An organic light emitting display device for displaying an image by controlling the amount of light emitted from the organic light emitting layer by using a flat panel display capable of reducing weight and volume, which is a disadvantage of a cathode ray tube (CRT), has attracted attention. An organic light emitting display (OLED) is a self-luminous element using a thin light emitting layer between electrodes and has an advantage that it can be thinned like a paper. The organic light emitting display OLED is divided into an active matrix OLED (AMOLED) and a passive matrix OLED (PMOLED).

At this time, the active matrix OLED (AMOLED) displays images by arranging pixels composed of three color (R, G, B) sub-pixels in a matrix form. Each sub-pixel includes an organic electroluminescent element and a cell driver for driving the organic electroluminescent element. The cell driver includes at least two thin film transistors and a storage capacitor connected between a gate line for supplying a scan signal, a data line for supplying a video data signal, and a common power supply line for supplying a common power supply signal, As shown in Fig.

The organic electroluminescent device includes an anode, a hole injection layer (HIL) and a hole transport layer (HTL) formed in each of the bank holes defined by the bank insulating film, and a hole transport layer A green light emitting layer formed in a bank hole in which a hole transporting layer is formed, a buffer layer formed on the entire surface of the substrate on which the red light emitting layer and the green light emitting layer are formed, a blue light emitting layer sequentially formed on the entire surface of the buffer layer, Layer (ETL), and a cathode.

At this time, the buffer layer is formed between the red light emitting layer, the green light emitting layer, and the blue light emitting layer to transfer electrons to the red light emitting layer and the green light emitting layer, respectively, and to transfer holes to the blue light emitting layer.

As described above, the buffer layer is formed between the red light emitting layer and the green light emitting layer and the blue light emitting layer to control the charge balance. However, holes from the red light emitting layer and the green light emitting layer are transferred from the blue light emitting layer to the blue light emitting peak Is generated.

As described above, a blue color interference phenomenon occurs in each of the red emission peak and the green emission peak, and red and green color characteristics are deteriorated.

SUMMARY OF THE INVENTION The present invention provides an organic light emitting display panel and a method of manufacturing the same that can improve the color characteristics of red and green.

For this, an organic light emitting display panel according to the present invention includes a thin film transistor formed on a substrate, a first electrode connected to the thin film transistor, a bank insulating film having a bank hole for exposing the first electrode, A red light emitting layer formed on the hole transporting layer formed in the bank hole and emitting red light, and a red light emitting layer formed on the hole transporting layer formed in the bank hole to emit green light A blue host layer formed on the front surface of the substrate on which the red and green light emitting layers are formed; a blue light emitting layer formed on the front surface of the blue host layer; and an electron transport layer And a second electrode.

Here, the triplet energy level of the blue host layer is formed to be higher than the triplet energy level of the red light emitting layer and the green light emitting layer.

The blue host layer has a triplet energy level (T1 level) of 2.5 eV to 3.0 eV.

In addition, the hole and electron mobility of the blue host layer is formed to be 10 ^-8 cm 2 / Vs to 10 ^-4 cm 2 / Vs.

The hole injection layer, the hole transport layer, the red emission layer, and the green emission layer may be formed by a solution process such as ink jet (Ink Jet), nozzle coating, spray coating, roll printing, ).

The blue host layer, the blue light emitting layer, the electron transport layer, and the second electrode are formed by a vacuum deposition method.

Here, the red light emitting layer and the green light emitting layer are formed of a low molecular weight material or a high molecular material, and the blue light emitting layer is formed of a low molecular weight material.

According to another aspect of the present invention, there is provided a method of manufacturing an organic light emitting display panel, including: forming a thin film transistor on a substrate; forming a first electrode connected to the thin film transistor; forming a bank insulating film on the first electrode Forming a bank hole through the bank insulating film to expose the first electrode; forming a hole injection layer and a hole transporting layer sequentially in each of the bank holes partitioned by the bank insulating film by a solution process; Forming a red light emitting layer on the hole transport layer formed in the bank hole by a solution process; forming a green light emitting layer on the hole transport layer formed in the bank hole by a solution process; The blue host layer, the blue light emitting layer, the electron transport layer, and the second electrode are sequentially formed by a vacuum deposition method It is characterized by including the steps:

Here, the blue host layer is formed of a material having a triple energy level higher than that of the red light emitting layer and the green light emitting layer.

Also, the blue host layer is characterized in that a material having a triplet energy level (T1 level) of 2.5 eV to 3.0 eV is used.

The blue host layer is characterized in that a material having a hole and electron mobility ranging from 10 ^-8 cm 2 / Vs to 10 ^-4 cm 2 / Vs is used.

The red light emitting layer and the green light emitting layer are formed of a low molecular weight material or a polymer material, and the blue light emitting layer is formed of a low molecular weight material.

The solution process is characterized by being one of ink jet (Ink Jet), nozzle coating (nozzle coating), spray coating (spray coating) and roll printing (roll printing).

The organic electroluminescent device according to an embodiment of the present invention can prevent a blue color interference phenomenon in each of a red emission peak and a green emission peak by forming a blue host layer in place of the buffer layer formed between the red emission layer and the green emission layer and the blue emission layer .

Thus, the red color characteristics emitted from the red light emitting layer and the green color characteristics emitted from the green light emitting layer can be improved.

1 is a cross-sectional view illustrating an organic light emitting display panel according to an exemplary embodiment of the present invention.
Fig. 2 is a diagram showing a general color coordinate graph.
FIG. 3 (a) is a band diagram according to a conventional organic electroluminescent device, and FIG. 3 (b) is a band diagram according to an organic electroluminescent device according to an embodiment of the present invention.
FIG. 4 is a graph comparing the red emission peak according to the organic light emitting device according to the comparative example and the red emission peak according to the organic light emitting device according to the embodiment of the present invention.
5 is a graph comparing the green emission peak according to the organic light emitting device according to the comparative example and the green emission peak according to the organic light emitting device according to the embodiment of the present invention.
6 is a graph showing a blue emission peak according to an organic electroluminescent device using a blue host layer and a blue emission peak according to an organic electroluminescent device having no blue host layer.
7A to 7G are cross-sectional views illustrating a method of manufacturing an organic light emitting display panel according to an embodiment of the present invention shown in FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The configuration of the present invention and the operation and effect thereof will be clearly understood through the following detailed description. Before describing the present invention in detail, the same components are denoted by the same reference symbols as possible even if they are displayed on different drawings. In the case where it is judged that the gist of the present invention may be blurred to a known configuration, do.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to FIGS. 1 to 7G.

1 is a cross-sectional view illustrating an organic light emitting display panel according to an exemplary embodiment of the present invention.

As shown in FIG. 1, the organic light emitting display panel includes a driving thin film transistor and an organic electroluminescent device connected to the driving thin film transistor.

The driving thin film transistor includes a buffer film 116 and an active layer 114 formed on a substrate 101 and a gate electrode 106 is formed between the channel region 114C of the active layer 114 and the gate insulating film 112 As shown in FIG. The source electrode 108 and the drain electrode 110 are formed so as to be insulated with the gate electrode 106 and the interlayer insulating film 126 interposed therebetween. The source electrode 108 and the drain electrode 110 are connected to the active layer through which the n + impurity is implanted through the interlayer insulating film 126 and the source contact hole 124S and the drain contact hole 124D penetrating the gate insulating film 112 The source region 114S and the drain region 114D, respectively. The active layer 114 includes a lightly doped drain (LDD) region (not shown) doped with an n-impurity between the channel region 114C and the source and drain regions 114S and 114D to reduce the off current ). Also, an organic passivation layer 119 formed of an organic insulating material is formed on the driving thin film transistor formed on the substrate 101. Alternatively, the protective film on the driving thin film transistor may be formed of two layers, that is, an inorganic protective film formed of an inorganic insulating material and an organic protective film formed of an organic insulating material.

The organic electroluminescent device includes a first electrode 232 connected to a drain electrode 110 of a driving thin film transistor, a bank insulating film 130 formed with a bank hole for exposing the first electrode 232, a bank insulating film 130, A hole injection layer (HIL) 234, a hole transport layer (HTL) 235 and a hole transport layer 235 formed in the bank hole are sequentially stacked in each of the bank holes defined by the bank layer A green light emitting layer 236G formed on the hole transport layer 235 formed in the bank hole and emitting green light and a red light emitting layer 236R formed on the substrate on which the red light emitting layer 236R and the green light emitting layer 236G are formed A blue light emitting layer 244 formed on the front surface of the blue host layer 242 and a blue light emitting layer 244 formed on the front surface of the blue light emitting layer 244, An electron transport layer (ETL) 246, an electron transport layer 246, And a second electrode 248 formed on the surface.

The first electrode 232 is formed of a transparent conductive electrode such as ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), or the like, as a transparent conductive oxide (TCO) .

The second electrode 248 is formed of a reflective metal material such as aluminum (Al) as a cathode. The second electrode 248 is formed by a vacuum deposition method in the same manner as the blue host layer 242, the blue light emitting layer 244, and the electron transport layer 246.

The red light emitting layer 236R is laminated in a bank hole defined by the bank insulating film 130, and is formed of a dopant of a red phosphorescent component to emit red light. The red light emitting layer 236R may be formed of a low molecular weight or high molecular material. The red light emitting layer 236R may be formed by ink jet, nozzle coating, spray coating, roll printing, or the like in the same manner as the hole injection layer 234 and the hole transport layer 235, (Soluble Process).

The red luminescent layer 236R is transported from the hole transport layer 235 to the red luminescent layer 236R and electrons are transmitted from the blue host layer 242 to the red luminescent layer 236R to generate electrons and holes in the red luminescent layer 236R The excitons are recombined to generate an exciton. As the exciton falls to the ground state, red light is emitted.

Generally, when red light is emitted from the red light emitting layer 236R, a color interference phenomenon occurs due to the blue light emitting layer 244 formed on the entire surface of the substrate 101. However, in the present invention, the blue host layer 242 is formed between the red light emitting layer 236R and the blue light emitting layer 244, thereby preventing the color interference phenomenon and improving the color characteristics.

The green light emitting layer 236G is laminated in a bank hole defined by the bank insulating film 130, and is formed of a dopant of a green phosphorescent component to emit green light. The green light emitting layer 236G may be formed of a low molecular weight material or a high molecular material. The green light emitting layer 236G may be formed by ink jet, nozzle coating, spray coating, roll printing or the like in the same manner as the hole injection layer 234 and the hole transport layer 235, (Soluble Process).

The green light emitting layer 236G is formed by transferring holes from the hole transporting layer 235 to the green light emitting layer 236G and electrons from the blue host layer 242 to the green light emitting layer 236G, As a result, an exciton is generated. As the exciton falls to a ground state, green light is emitted.

Generally, when green is emitted from the green light emitting layer 236G, a color interference phenomenon is caused by the blue light emitting layer 244 formed on the entire surface of the substrate 101. [ However, in the present invention, the blue host layer 242 is formed between the green light-emitting layer 236G and the blue light-emitting layer 244, thereby preventing the color interference phenomenon and improving the color characteristics.

The blue light emitting layer 244 is formed on the front surface of the substrate 101 on which the blue host layer 242 is formed and is formed of a dopant of a blue fluorescent component to emit blue light. The blue light emitting layer 244 may be formed of a low molecular material. Since the blue luminescent layer 244 can be displayed as a sky blue when it is formed of an organic material for solution processing, it is possible to use a deep blue (deep blue) organic material having good efficiency, ) Can be displayed. That is, the color coordinates shown in FIG. 2 will be briefly described. As the value of CIEy for the blue region becomes smaller, deep blue is displayed. As the value of CIEy for the blue region becomes larger, sky blue ). That is, when the blue light emitting layer 244 is deep blue, the color reproducibility and the sensation are improved. When the blue light emitting layer 244 is formed of an organic material for a solution process, sky blue is displayed, There arises a problem that the driving voltage is increased. Accordingly, the blue light emitting layer 244 of the present invention is formed of a vacuum deposition organic material to display a deep blue color, thereby improving lifetime and efficiency, and lowering the driving voltage.

The blue host layer 242 is formed between the red light emitting layer 236R and the green light emitting layer 236G and the blue light emitting layer 244 to form a charge balance between the red and green light emitting layers 236R and 236G and the blue light emitting layer 244. [ . Specifically, the blue host layer 242 transmits electrons to the red light emitting layer 236R and the green light emitting layer 236G and transmits holes to the blue light emitting layer 244.

The blue host layer 242 is formed of a blue host material to prevent a blue interference phenomenon from occurring when light is emitted from each of the red light emitting layer 236R and the green light emitting layer 236G.

3 (a), the conventional organic electroluminescent device has a red light emitting layer, a blue light emitting layer (red light emitting layer) 10, a blue light emitting layer 14, A peak is generated, and a blue emission peak is generated at the green emission peak.

3 (b), the blue host layer 242 may include a red light emitting layer and a green light emitting layer 236G in order to suppress the transfer of holes from the red light emitting layer and the green light emitting layer 236G to the blue light emitting layer 244, respectively ) And the blue light emitting layer 244.

Specifically, the blue host layer 242 has a triple anti-blocking effect due to the triplet energy level of the blue host higher than the triplet energy level (T1 level) of each of the red light emitting layer 236R and the green light emitting layer 236G. That is, the triplet energy level (T1 level) of the blue host layer 242 is formed to be higher than the triplet energy level of the red light emitting layer 236R and the green light emitting layer 236G to form the red light emitting layer 236R and the green light emitting layer 236G. Holes from each other do not pass holes due to the high triplet energy levels of the blue host layer 242. Accordingly, the blue emission peak can be prevented from occurring in the red emission peak, and the blue emission peak can be prevented from occurring in the green emission peak.

The triplet energy level (T1 Level) of the blue host layer 242 is 2.5 eV to 3.0 eV and the hole and electron mobility of the blue host layer 242 is 10 ^-8 cm 2 / Vs to 10 ^-4 cm 2 / Vs.

The blue host layer 242 is formed by a vacuum deposition method (evaporation process) in the same manner as the blue light emitting layer 244, the electron transport layer 246, and the second electrode 248.

FIG. 4 is a graph comparing the red emission peak according to the organic light emitting device according to the comparative example and the red emission peak according to the organic light emitting device according to the embodiment of the present invention.

4 is a graph showing a red emission peak according to an organic electroluminescent device according to a comparative example, and a second curve 32 shown in FIG. 4 is a graph showing an emission peak according to an organic electroluminescent device according to an embodiment of the present invention. And the red emission peak.

First, in the organic electroluminescent device according to the comparative example, a positive electrode to which a drain electrode of a driving thin film transistor is connected, a bank insulating film in which a bank hole for exposing the positive electrode is formed, and a hole injection A green light emitting layer formed on the hole injecting layer in the bank hole, a buffer layer sequentially formed on the entire surface of the substrate on which the red light emitting layer and the green light emitting layer are formed, the blue light emitting layer, the electron transporting layer , And a second electrode.

An organic electroluminescent device according to an embodiment of the present invention includes a first electrode 232 connected to a drain electrode 110 of a driving thin film transistor and a bank insulating layer 130 having a bank hole for exposing the first electrode 232, A hole injecting layer 234 and a hole transporting layer 235 which are sequentially stacked in the bank holes partitioned by the bank insulating film 130 and a hole transporting layer 235 formed in the bank hole, A green light emitting layer 236G for emitting green light formed on the hole transporting layer 235 formed in the bank hole and a light emitting layer 236G for emitting green light are sequentially formed on the front surface of the substrate 101 on which the red light emitting layer 236R and the green light emitting layer 236G are formed. A blue light emitting layer 244, an electron transporting layer 246, and a second electrode 248 stacked on the light emitting layer 242.

As shown in the first curve 30 of FIG. 4, the holes transferred from the red light emitting layer are transferred to the blue light emitting layer, and a blue peak appears at the red light emitting peak. As a result, when emitting red light, blue light emission interferes with the characteristics of red color.

However, as shown in the second curve 32 of FIG. 4, the holes delivered from the red light emitting layer do not exceed the energy barrier of the blue host layer, so that no blue peak appears at the red light emitting peak. As a result, the blue light emission does not cause interference during the red light emission, thereby improving the red color characteristic.

5 is a graph comparing the green emission peak according to the conventional organic light emitting device and the green emission peak according to the organic light emitting device according to the embodiment of the present invention.

5 is a graph showing a red emission peak according to an organic electroluminescent device according to a comparative example, and a second curve 42 shown in FIG. 5 is a graph showing a red emission peak according to an organic electroluminescent device according to an embodiment of the present invention. And the red emission peak.

As shown in the first curve 40 of FIG. 5, the holes transferred from the green light emitting layer are transferred to the blue light emitting layer, and a blue peak appears at the green light emitting peak. As a result, when green light is emitted, blue light emission interferes with the green color.

However, as shown in the second curve 42 of FIG. 5, the holes delivered from the green light emitting layer do not exceed the energy barrier of the blue host layer, so that no blue peak appears at the green light emitting peak. Accordingly, when the green light emission is performed, the blue light emission does not cause interference, so the green characteristic is improved.

On the other hand, a blue host layer is used for an organic electroluminescent device according to an embodiment of the present invention. However, even if a blue host layer is used, the color characteristics of red and green must be improved without affecting the blue emission peak, Layer does not affect the blue emission peak.

6 is a graph showing a blue emission peak according to an organic electroluminescent device using a blue host layer and a blue emission peak according to an organic electroluminescent device having no blue host layer.

Case A in FIG. 6 shows a blue emission peak according to an organic electroluminescent device in which a blue host layer is not formed, and an organic electroluminescent device according to Case A has an ITO / HIL / HTL / blue emission layer B-EML) (25 nm) / ETL / EIL / Cathode. Here, the thickness of the blue light emitting layer is 25 nm.

Case B in FIG. 6 shows a blue emission peak according to an organic electroluminescent device in which a blue host layer is formed, and an organic electroluminescent device according to Case B has an ITO / HIL / HTL / blue host layer (5 nm) / B-EML (25 nm) / ETL / EIL / Cathode structure. Here, the thickness of the blue luminescent layer is 25 nm, and the thickness of the blue hot layer is 5 nm.

6 shows the blue emission peak according to the organic electroluminescent device formed with the blue host layer, and the organic electroluminescent device according to Case C has the ITO / HIL / HTL / BHL (5 nm) / B- / ETL / EIL / Cathode structure. Here, the thickness of the blue light emitting layer is 20 nm, and the thickness of the blue hot layer is 5 nm.

6 shows the blue emission peak according to the organic electroluminescent device formed with the blue host layer, and the organic electroluminescent device according to Case D is ITO / HIL / HTL / BHL (10 nm) / B- / ETL / EIL / Cathode structure. Here, the thickness of the blue light emitting layer is 25 nm, and the thickness of the blue hot layer is 10 nm.

6 shows a blue emission peak according to an organic electroluminescent device having a blue host layer formed thereon. The organic electroluminescent device according to Case E is an ITO / HIL / HTL / BHL (10 nm) / B- / ETL / EIL / Cathode structure. Here, the thickness of the blue light emitting layer is 15 nm and the thickness of the blue hot layer is 10 nm.

CIEx CIEy Casea 0.141 0.091 Case B 0.141 0.093 Case C 0.142 0.090 Case D 0.141 0.099 Case E 0.141 0.091

[Table 1] shows the color coordinate values of the organic electroluminescent device according to the cases A, B, C, D, and E.

Thus, even when a blue host layer is inserted between the hole transporting layer and the blue light emitting layer as shown in Table 1 and Fig. 6, there is no change in blue color characteristics.

7A to 7G are cross-sectional views illustrating a method of manufacturing an organic light emitting display panel according to an embodiment of the present invention shown in FIG.

7A, a driving thin film transistor including a buffer film 116, an active layer 114, a gate electrode 106, a source electrode 108, and a drain electrode 110 is formed on a substrate 101.

Specifically, an inorganic insulating material such as SiO ₂ is completely deposited on the substrate 101 to form a buffer film 116. The active layer 114 is formed by depositing amorphous silicon on the buffer film 116 and then crystallizing the amorphous silicon in a laser / heat treatment process to become poly-silicon. Then, the polysilicon is subjected to photolithography and etching Patterning process.

Then, an inorganic insulating material is deposited on the buffer film 116 on which the active layer 114 is formed, thereby forming the gate insulating film 112. The gate electrode 106 is formed by forming a gate metal layer on the gate insulating film 112 and then patterning the gate metal layer by a photolithography process and an etching process. The source region 114S and the drain region 114D facing each other with the channel region 114C of the active layer therebetween by injecting n + impurity into each of the active layers 114 using the gate electrode 106 as a mask .

Thereafter, an inorganic insulating material is deposited on the gate insulating film 112 on which the gate electrode 106 is formed, thereby forming an interlayer insulating film 126. Then, source and drain contact holes 124S and 124D are formed through the interlayer insulating film 126 and the gate insulating film 112 to expose the source and drain regions 114S and 114D of the active layer, respectively, by a photolithography process and an etching process .

Next, a source / drain metal layer is formed on the interlayer insulating film 126 on which the source and drain contact holes 124S and 124D are formed, and the source / drain metal layer is patterned by a photolithography process and an etching process to form the source and drain electrodes 108 and 110 ). The source and drain electrodes 108 and 110 are connected to the source region 114S and the drain region 114D through the source and drain contact holes 124S and 124D, respectively.

Referring to FIG. 7B, an organic passivation layer 119 having a pixel contact hole 120 is formed on a substrate 101 on which source and drain electrodes 108 and 110 are formed.

Specifically, an organic insulating material such as an acrylic resin is formed on the entire surface of the substrate 101 on which the source and drain electrodes 108 and 110 are formed, thereby forming the organic passivation layer 119. Then, the organic passivation layer 119 is patterned by the photolithography process and the etching process, thereby forming the pixel contact hole 120. [ The pixel contact hole 120 exposes the drain electrode 110 through the organic passivation layer 119.

Referring to FIG. 7C, a first electrode 232 is formed on a substrate 101 on which an organic passivation layer 119 is formed.

Specifically, a transparent conductive layer such as indium tin oxide (ITO), indium zinc oxide (IZO), or the like is formed on the substrate 101 on which the organic protective layer 119 is formed through a deposition method such as a sputtering method. . Subsequently, the transparent electrode is patterned by a photolithography process and an etching process to form a first electrode 232 connected to the drain electrode 108 of the driving transistor.

7D, a bank insulating layer 130 having a bank hole 135 is formed on a substrate 101 on which a first electrode 232 is formed.

Specifically, an organic insulating material such as an acrylic resin is formed entirely on the substrate 101 on which the first electrode 232 is formed through a coating method such as spin-spin coating or spin coating. Then, the organic insulating film is patterned through the photolithography process and the etching process, thereby forming the bank insulating film 130 including the bank holes 135. [ The bank holes 135 pass through the bank insulating film 130 of each pixel region to expose the first electrodes 232.

Referring to FIG. 7E, a hole injection layer 234 and a hole transport layer 235 are formed on a substrate 101 on which a bank insulating film 130 is formed.

Specifically, the hole injection layer 234 and the hole transport layer 235 are formed by ink jet, nozzle coating, spray coating, or the like in the bank holes 135 provided between the bank insulating films 130. [ , Roll printing, and the like.

Referring to FIG. 7F, a red light emitting layer 236R and a green light emitting layer 236G are formed in the bank holes 135 in which the hole injection layer 234 and the hole transport layer 235 are formed.

More specifically, a red light emitting layer 236R and a green light emitting layer 236G are formed on each of the bank holes 135 in which the hole injection layer 234 and the hole transport layer 235 are formed by ink jet, nozzle coating, Such as spray coating, roll printing, and the like. At this time, the red light emitting layer 236R is formed of a dopant of a red phosphorescent component, and may be formed of a low molecular weight material or a high molecular material. The green light emitting layer 236G is formed of a dopant of a green phosphorescent material and may be formed of a low molecular weight material or a high molecular material.

7G, a blue host layer 242, a blue luminescent layer 244, an electron transport layer 246 and a second electrode 248 are formed on the entire surface of a substrate 101 on which a red luminescent layer 236R and a green luminescent layer 236G are formed. Are sequentially formed through a vacuum deposition method.

Specifically, the blue host layer 242 is formed of a material higher than the triplet energy level of the red light emitting layer 236R and the green light emitting layer 236G. At this time, the blue host layer 242 uses a material having a triplet energy level (T1 Level) of 2.5 eV to 3.0 eV. Further, the blue host layer 242 uses a material having a hole and electron mobility ranging from 10 ^-8 cm 2 / Vs to 10 ^-4 cm 2 / Vs.

The blue light emitting layer 244 is formed of a dopant of a blue fluorescent component and can be formed of a low molecular material.

As described above, the hole injection layer 234, the hole transport layer 235, the red light emitting layer 236R, and the green light emitting layer 236G are formed through a solution process, and the blue host layer 242, the blue light emitting layer 244, The electron transport layer 246, and the second electrode 248 are formed through a vacuum deposition method. That is, the red and green light emitting layers 236R and 236G are formed through a solution process to reduce the cost, while the color coordinates and the blue light emitting layer 244 having poor efficiency are formed of a vacuum deposition organic material having good color coordinates and efficiency. Accordingly, the present invention can improve the color coordinates and efficiency of the blue light emitting layer 244 while reducing the cost.

The foregoing description is merely illustrative of the present invention, and various modifications may be made by those skilled in the art without departing from the spirit of the present invention. Accordingly, the embodiments disclosed in the specification of the present invention are not intended to limit the present invention. The scope of the present invention should be construed according to the following claims, and all the techniques within the scope of equivalents should be construed as being included in the scope of the present invention.

101: substrate 108: source electrode
110: drain electrode 112: gate insulating film
114: active layer 116: buffer film
120: Pixel contact hole 126: Interlayer insulating film
130: bank insulating film 232: first electrode
234: Hole injection layer 235: Hole transport layer
236R: red luminescent layer 236G: green luminescent layer
242: blue host layer 244: blue light emitting layer
246: electron transport layer 248: second electrode

Claims (13)

A thin film transistor formed on a substrate;
A first electrode connected to the thin film transistor;
A bank insulating film on which a bank hole for exposing the first electrode is formed;
A hole injecting layer and a hole transporting layer which are sequentially stacked in each bank hole partitioned by the bank insulating film;
A red light emitting layer formed on the hole transporting layer formed in the bank hole and emitting red light;
A green light emitting layer formed on the hole transporting layer formed in the bank hole and emitting green light;
A blue host layer formed on a front surface of the substrate on which the red light emitting layer and the green light emitting layer are formed;
A blue light emitting layer formed on the front surface of the blue host layer;
And an electron transport layer and a second electrode sequentially formed on a front surface of the blue light emitting layer. The method according to claim 1,
Wherein a triplet energy level of the blue host layer is higher than a triplet energy level of the red light emitting layer and the green light emitting layer. The method according to claim 1,
Wherein the blue host layer has a triplet energy level (T1 level) of 2.5 eV to 3.0 eV. The method according to claim 1,
Wherein the blue host layer has a hole and electron mobility of 10 ^-8 ㎠ / Vs to 10 ^-4 ㎠ / Vs. The method according to claim 1,
The hole injection layer, the hole transport layer, the red emission layer, and the green emission layer may be formed by a solution process such as ink jet, nozzle coating, spray coating, roll printing, Wherein the organic electroluminescent display panel is formed on the substrate. The method according to claim 1,
Wherein the blue host layer, the blue light emitting layer, the electron transport layer, and the second electrode are formed by a vacuum deposition method. The method according to claim 1,
Wherein the red light emitting layer and the green light emitting layer are formed of a low molecular weight material or a high molecular material, and the blue light emitting layer is formed of a low molecular weight material. Providing a thin film transistor on a substrate;
Forming a first electrode connected to the thin film transistor;
Forming a bank insulating film on the first electrode, forming a bank hole through the bank insulating film to expose the first electrode;
Forming a hole injecting layer and a hole transporting layer sequentially in each of the bank holes partitioned by the bank insulating film by a solution process;
Forming a red light emitting layer in a solution process on the hole transporting layer formed in the bank hole;
Forming a green light emitting layer by a solution process on a hole transporting layer formed in the bank hole;
Forming a blue host layer, a blue light emitting layer, an electron transport layer, and a second electrode sequentially on the front surface of the substrate on which the red light emitting layer and the green light emitting layer are formed by a vacuum deposition method. Way. 9. The method of claim 8,
Wherein the blue host layer is formed of a material higher than a triplet energy level of the red light emitting layer and the green light emitting layer. 9. The method of claim 8,
Wherein the blue host layer uses a material having a triplet energy level (T1 level) of 2.5 eV to 3.0 eV. 9. The method of claim 8,
Wherein the blue host layer uses a material having a hole and electron mobility ranging from 10 ^-8 cm 2 / Vs to 10 ^-4 cm 2 / Vs. 9. The method of claim 8,
Wherein the red light emitting layer and the green light emitting layer are formed of a low molecular weight material or a high molecular material and the blue light emitting layer is formed of a low molecular weight material. 9. The method of claim 8,
Wherein the solution process is any one of ink jet (Ink Jet), nozzle coating (nozzle coating), spray coating (spray coating) and roll printing (roll printing).

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