TW201702211A - Organic emitting device - Google Patents

Abstract

An organic light emitting device is provided, and includes a substrate, a first electrode, an organic light emitting layer, a second electrode and a crystalline layer. The first electrode is disposed on the substrate. The organic light emitting layer is disposed on the first electrode. The second electrode is disposed on the organic light emitting layer, wherein the organic light emitting layer is disposed between the first electrode and the second electrode. The crystalline layer is disposed on the second electrode, wherein the second electrode is disposed between the crystalline layer and the organic light emitting layer. Material of the crystalline layer includes a compound represent by formula (1), formula (2) or formula (3). X in formula (1) may be Si, Ge, Sn, Pb or C.

Description

Organic light-emitting element

The present invention relates to a light-emitting element, and more particularly to an organic light-emitting element.

With the advancement of technology, flat panel displays have been the most watched display technology in recent years. Among them, the organic light-emitting display has great application potential due to its self-illumination, no viewing angle dependence, power saving, simple process, low cost, low temperature operating range, high response speed and full color, and is expected to become the next generation. The mainstream of flat panel displays.

In an organic light emitting display, an upper-emission type top-emission OLED has high color purity and high efficiency by a microcavity effect. However, the upper-emitting organic light-emitting display has a problem that a large viewing angle is liable to have a color shift, and the light is easily confined in the display due to the total reflection waveguide effect, so that it has a disadvantage of poor light-emitting efficiency.

The invention provides an organic light-emitting element with an improved large-viewing role Bias phenomenon and high light extraction efficiency.

The organic light emitting device of the present invention includes a substrate, a first electrode, an organic light emitting layer, a second electrode, and a crystalline layer. The first electrode is on the substrate. The organic light emitting layer is on the first electrode. The second electrode is located on the organic light emitting layer, wherein the organic light emitting layer is located between the first electrode and the second electrode. The crystal layer is located on the second electrode, wherein the second electrode is located between the crystal layer and the organic light-emitting layer, and the material of the crystal layer comprises a compound represented by the formula (1), wherein X may be Si, Ge, Sn, Pb or C And the crystalline layer has a rough surface

The organic light emitting device of the present invention includes a substrate, a first electrode, an organic light emitting layer, a second electrode, and a crystalline layer. The first electrode is on the substrate. The organic light emitting layer is on the first electrode. The second electrode is located on the organic light emitting layer, wherein the organic light emitting layer is located between the first electrode and the second electrode. The crystal layer is located on the second electrode, wherein the second electrode is located between the crystal layer and the organic light-emitting layer, the material of the crystal layer comprises the compound represented by the formula (2), and the crystal layer has a rough surface

The organic light emitting device of the present invention includes a substrate, a first electrode, an organic light emitting layer, a second electrode, and a crystalline layer. The first electrode is on the substrate. The organic light emitting layer is on the first electrode. The second electrode is located on the organic light emitting layer, wherein the organic light emitting layer is located between the first electrode and the second electrode. The crystal layer is located on the second electrode, wherein the second electrode is located between the crystal layer and the organic light-emitting layer, the material of the crystal layer comprises the compound represented by the formula (3), and the crystal layer has a rough surface

In an embodiment of the invention, the crystalline layer has a maximum thickness of less than 1 um.

In an embodiment of the invention, the first electrode includes a reflective electrode, and the second electrode includes a penetrating electrode.

In an embodiment of the invention, a buffer layer is further disposed between the second electrode and the crystalline layer.

In an embodiment of the invention, the rough surface is a light exiting surface.

Based on the above, the organic light-emitting element of the present invention includes a crystal layer formed of the compounds represented by the formulae (1) to (3), which has a rough surface. The crystal layer can effectively destroy the total reflection of the internal light emission of the element, and the light excited in the organic light-emitting element is led out to improve the light-emitting efficiency and greatly improve the phenomenon of the large-view character. Therefore, the organic light-emitting display using the organic light-emitting element has better display quality, and the organic light-emitting illumination device using the organic light-emitting element has good light-emitting efficiency.

The above described features and advantages of the invention will be apparent from the following description.

100‧‧‧Organic light-emitting elements

102‧‧‧Substrate

110‧‧‧First electrode

120‧‧‧Organic light-emitting layer

122‧‧‧Electronic transport layer

124‧‧‧ hole transport layer

126‧‧‧ hole injection layer

130‧‧‧second electrode

140‧‧‧ Crystallized layer

142‧‧‧Rough surface

150‧‧‧buffer layer

1 is a schematic cross-sectional view of an organic light emitting device in accordance with an embodiment of the present invention.

2 is a schematic cross-sectional view of an organic light emitting device in accordance with an embodiment of the present invention.

1 is a schematic cross-sectional view of an organic light emitting device in accordance with an embodiment of the present invention. Referring to FIG. 1 , the organic light emitting device 100 of the present embodiment includes a substrate 102 , a first electrode 110 , an organic light emitting layer 120 , a second electrode 130 , and a crystal layer 140 . In this embodiment, the substrate 102 can be a hard substrate or a flexible substrate, such as a glass substrate, a rigid plastic substrate, a metal substrate, a wafer, or a ceramic substrate. The flexible substrate is, for example, an organic substrate such as a polyimide substrate, a polycarbonate substrate, a polyphthalate substrate, a polyethylene naphthalate substrate, a polypropylene substrate, a polyethylene substrate, a polystyrene substrate, Other suitable substrates, substrates of the above polymer derivatives, or thin metal or alloy substrates. The substrate 102 may be made of a transparent material or a non-transparent material.

The first electrode 110 is located on the substrate 102. The second electrode 130 is located on the organic light emitting layer 120 , and the second electrode 130 is located between the crystalline layer 140 and the organic light emitting layer 120 . In the present embodiment, the organic light emitting element 100 is an upper light emitting type organic light emitting display, and in this case, the first electrode 110 is, for example, a reflective electrode. The second electrode 130 is, for example, a penetrating electrode. The first electrode 110 may include a reflective material, such as a conductive material such as a metal, an alloy, a metal oxide, or a stacked layer of a metal and a transparent metal oxide conductive material, such as gold, silver, aluminum, Molybdenum, copper, titanium, chromium, tungsten or other suitable metal, although the invention is not limited thereto. The second electrode 130 may include a transparent metal oxide conductive material. The transparent metal oxide conductive material is, for example, indium tin oxide, indium zinc oxide, aluminum tin oxide, aluminum zinc oxide, indium antimony zinc oxide or other suitable metal oxide, or a stack of at least two of the above Layer, however, the invention is not limited thereto. The first electrode 110 and the second electrode 130 may be formed by an evaporation process and a fine metal mask (FFM), but the invention is not limited thereto. For example, the first electrode 110 and the second electrode 130 may also be formed using a sputtering process, or a chemical vapor deposition process or physical vapor deposition, and formed by a photolithography process or a fine metal mask. In the present embodiment, the first electrode 110 is, for example, an anode, and the second electrode 130 is, for example, a cathode. However, it must be noted that the anodes and anodes of the first electrode 110 and the second electrode 130 are subject to design requirements and are subject to change.

The organic light emitting layer 120 is located on the first electrode 110 and located between the first electrode 110 and the second electrode 130. In this embodiment, the organic light emitting layer 120 may include a red organic light emitting pattern, a green organic light emitting pattern, a blue organic light emitting pattern, a light emitting pattern of other colors, or a combination of the above light emitting patterns. The method of forming the organic light-emitting layer 120 is, for example, an evaporation method, a coating method, a deposition method, or other suitable methods. In the present embodiment, in order to further improve the luminous efficiency of the organic light emitting element 100, the electron transport layer 122 and the hole transport layer 124 are further disposed. The electron transport layer 122 is composed of an electron transport material, for example, disposed between the organic light emitting layer 120 and the second electrode 130. The hole transport layer 124 is composed of a hole transport material, and is disposed, for example, between the organic light-emitting layer 120 and the first electrode 110. Further, a hole injection layer 126 may be further included. The hole injection layer 126 is composed of a hole injection material, and is disposed, for example, between the first electrode 110 and the hole transport layer 124. In another embodiment, the electron injection layer may be further disposed between the second electrode 130 and the electron transport layer 122. However, it must be noted that the configuration of the hole injection layer 126, the hole transport layer 124, the electron transport layer 122, and the electron injection layer is optional, and may not be present in the organic light emitting device 100. In the embodiment, the organic light-emitting element is an ordinary type OLED, but the invention is not limited thereto. In other embodiments, the organic light-emitting element can also be applied to an inverted type OLED. .

In the embodiment, the organic light emitting device 100 further includes a buffer layer 150 between the second electrode 130 and the crystal layer 140. The material of the buffer layer 150 is usually an organic material such as a hole transport material, such as NPB (N, N'-Bis (naphthalene-1-yl)-N, N'-bis (phenyl)-benzidine), β-NPB ( N,N'-Bis(naphthalene-2-yl)-N,N'-bis(phenyl)-benzidine), or inorganic materials such as lithium fluoride (LiF), aluminum fluoride (AlF ₃ ), etc. In addition to the function of buffer protection, the surface layer of the crystal layer 140 can be modified to match.

The crystal layer 140 is located on the second electrode 130. In the present embodiment, the crystal layer 140 is formed, for example, on the buffer layer 150, and is located, for example, at the outermost side of the organic light emitting element 100. The molecular structure of the material of the crystal layer 140 is a structure with good stereo symmetry and a single bond bond in the molecule, and the molecular structure can be rotated and easily packed tightly, so that the surface energy is minimal, reaching the autocrystalline state, and the molecular weight is 320. Between ~515. In the present embodiment, the material of the crystal layer 140 includes a compound represented by the formula (1), wherein X may be Si, Ge, Sn, Pb or C, which are respectively from the formula (1-I) to the formula (1-V) Said tetraphenylsilane (TPS), tetraphenyl germanium (TPGe), tetraphenyltin (TPT), tetraphenyl plumbane (TPPb) or tetraphenylmethane , TPM), 9,9'-bifluorene (BiF) represented by the formula (2) or 1,4-bis(diphenylamino)benzene represented by the formula (3) (1, 4) -Bis(diphenylamino)bezene,BisB)

. The tetraphenylnonane represented by the formula (1-I) has a molecular weight of 336, and the tetraphenylphosphonium represented by the formula (1-II) has a molecular weight of 380 and tetraphenyltin represented by the formula (1-III). The molecular weight is 427, the molecular weight of tetraphenyl lead represented by formula (1-IV) is 515, the molecular weight of tetraphenylene represented by formula (1-V) is 320, and 9,9 represented by formula (2). The molecular weight of '-biguanidine is 330, and the molecular weight of 1,4-bis(diphenylamino)benzene represented by the formula (3) is 412.

The method of forming the crystal layer 140 is an evaporation process. In the present embodiment, a compound represented by the formula (1-I), the formula (1-II), the formula (1-III), the formula (1-IV) or the formula (1-V), from the formula (2) The BiF or the BisB represented by the formula (3) is auto-crystallization after being vapor-deposited on the second electrode 130, and has good crystal uniformity. The maximum thickness of the crystal layer 140 is, for example, less than 1 um, and the thickness of the crystal layer 140 may be 0.5 um to 5 um. Due to the nature of the crystalline material, the formed crystalline layer 140 is not a flat surface but forms a textured layer of irregularities. For example, the vaporized layer 140 obtained by evaporation has an average thickness of about 0.3 um, but among them The thickness distribution range can be 0.2um~1um. That is, the crystal layer 140 has a rough surface 142, thus forming an uneven light guiding layer. As a result, the light generated by the excitation in the organic light emitting element 100 can be effectively guided out through the rough surface 142 of the crystal layer 140. That is, the rough surface 142 of the crystal layer 140 is, for example, a light-emitting surface. Wherein the compound represented by the formula (1-I), the formula (1-II), the formula (1-III), the formula (1-IV) or the formula (1-V) and the BiF represented by the formula (2) have A relatively uniform crystalline state is therefore suitable for use in an upper-emitting organic light-emitting display. The BisB represented by the formula (3) has a relatively obvious crystal boundary, and a relatively obvious light scattering phenomenon is caused to deteriorate the resolution, so that the display quality of the display is poor, and thus it is suitable for application to an organic light-emitting illumination device. In the present embodiment, the crystal layer 140 is deposited on the buffer layer 150 as an example, but the invention is not limited thereto. In another embodiment, as shown in FIG. 2, the crystalline layer 140 may also be directly evaporated on the second electrode 130. In other words, the organic light emitting element 100 may not include the buffer layer 150.

In the present embodiment, since the compound represented by the formula (1-I) to (3) has stereo symmetry and an appropriate molecular weight, it has self-crystallization characteristics. That is, after the material layer of the compound represented by the formula (1-I) to (3) is vapor-deposited on the second electrode 130, it can be crystallized to form a rough surface 142 without undergoing a reheating step. Crystal layer 140. The rough surface 142 of the crystalline layer 140 can destroy the total reflection within the organic light emitting element 100 to direct the light. Therefore, it is possible to greatly improve the light-emitting efficiency and improve the phenomenon of the big-view character, such as improving the red-light angle of the orange and the overall display blue-green. In this way, the organic light emitting display using the organic light emitting element has better display quality, and the organic light using the organic light emitting element The light illumination device has good light extraction efficiency. In addition, since the material of the crystal layer has self-crystallization characteristics and can be self-crystallized without undergoing a reheating step, the present invention is advantageous in simplifying the process steps of the organic light emitting device, thereby reducing the process cost of the organic light emitting device.

The experimental examples are enumerated below to verify the effects of the present invention.

In order to prove that the organic light-emitting device described in the above embodiment of the present invention has preferable device characteristics, it is compared with Comparative Examples 1 to 9 using Experimental Examples 1 to 7. Experimental Examples 1 to 7 have the structure of the organic light-emitting device shown in Fig. 1, and Experimental Examples 1 to 7 form the compounds represented by the formulae (1-I) to (3) on the buffer layer by vapor deposition. The material layer was used as a crystal layer, and the thickness of the material layer to be evaporated was 0.3 μm. The difference between Comparative Examples 1 to 7 and Experimental Examples 1 to 7 was that the material layer was not formed. Comparative Examples 8 to 9 have the structure of the organic light-emitting device shown in FIG. 1, and Comparative Examples 8 to 9 are formed by vapor deposition on the buffer layer, respectively, including 1,4,5,8-naphthalenetetracarboxylic anhydride (NTDA). And a layer of material of triphenylene, the thickness of the material layer evaporated is 0.3 um. The elemental characteristics of the organic light-emitting elements of Experimental Examples 1 to 7 and Comparative Examples 1 to 9 were tested, and the results are shown in Table 1.

Compared with Comparative Examples 1 to 7, Experimental Examples 1 to 7 have an improved color shift phenomenon, and luminous efficiency increase values were 26%, 23%, 14%, 20%, 31%, 39%, and 37%, respectively. Further, as is apparent from Comparative Examples 8 and 9, although NTDA and triphenylene have a symmetrical chemical structure, they are not stereo symmetric structures and are less likely to form a crystal stack due to a small molecular weight, resulting in poor film formation during vapor deposition. . Therefore, it is understood from the above experimental results that the provision of the crystal layer having the compound represented by the formula (1-I) to (3) on the outermost side of the organic light-emitting element can effectively improve the color shift and enhance the light-emitting efficiency.

As described above, the organic light-emitting element of the present invention includes a crystal layer formed of the compounds represented by the formulae (1-I) to (3) such that the organic light-emitting element has a rough light-emitting surface. The crystal layer can destroy the total reflection in the organic light-emitting element to light out, thereby improving the light-emitting efficiency and reducing the bias of the large-view character. For example, the problem of the red-light large viewing angle of the top-emission AMOLED and the overall display blue-green color can be greatly improved. As a result, the organic light-emitting display using the organic light-emitting element has better display quality, and the organic light-emitting illumination device using the organic light-emitting element has good light-emitting efficiency. Further, since the compounds represented by the formulae (1-I) to (3) have stereo symmetry and an appropriate molecular weight, they have self-crystallization characteristics, that is, they are uniformly crystallized into a crystal layer after vapor deposition, so that they can be omitted. To carry out the heating step of crystallization. As such, the process of the organic light emitting device has a reduced step and a shortened time, which is advantageous in reducing the cost of the organic light emitting device.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and any one of ordinary skill in the art can make some changes and refinements without departing from the spirit and scope of the present invention. The scope of the invention is defined by the scope of the appended claims.

100‧‧‧Organic light-emitting elements

102‧‧‧Substrate

110‧‧‧First electrode

120‧‧‧Organic light-emitting layer

122‧‧‧Electronic transport layer

124‧‧‧ hole transport layer

126‧‧‧ hole injection layer

130‧‧‧second electrode

140‧‧‧ Crystallized layer

142‧‧‧Rough surface

150‧‧‧buffer layer

Claims (15)

An organic light emitting device comprising: a substrate; a first electrode on the substrate; an organic light emitting layer on the first electrode; and a second electrode on the organic light emitting layer, wherein the organic light emitting layer is located Between the first electrode and the second electrode; and a crystal layer on the second electrode, wherein the second electrode is located between the crystal layer and the organic light-emitting layer, and the material of the crystal layer comprises a compound represented by 1), wherein X may be Si, Ge, Sn, Pb or C, and the crystal layer has a rough surface The organic light-emitting device of claim 1, wherein the crystalline layer has a maximum thickness of less than 1 μm. The organic light-emitting device of claim 1, wherein the first electrode comprises a reflective electrode, and the second electrode comprises a penetrating electrode. The organic light-emitting device of claim 1, further comprising a buffer layer between the second electrode and the crystal layer. The organic light-emitting element of claim 1, wherein the rough surface is a light-emitting surface. An organic light emitting device comprising: a substrate; a first electrode on the substrate; an organic light emitting layer on the first electrode; and a second electrode on the organic light emitting layer, wherein the organic light emitting layer is located Between the first electrode and the second electrode; and a crystal layer on the second electrode, wherein the second electrode is located between the crystal layer and the organic light-emitting layer, and the material of the crystal layer comprises 2) a compound represented, and the crystal layer has a rough surface The organic light-emitting device of claim 6, wherein the crystalline layer has a maximum thickness of less than 1 um. The organic light-emitting device of claim 6, wherein the first electrode comprises a reflective electrode, and the second electrode comprises a penetrating electrode. The organic light-emitting device of claim 6, further comprising a buffer layer between the second electrode and the crystal layer. The organic light-emitting element of claim 6, wherein the rough surface is a light-emitting surface. An organic light emitting device comprising: a substrate; a first electrode on the substrate; an organic light emitting layer on the first electrode; and a second electrode on the organic light emitting layer, wherein the organic light emitting layer is located Between the first electrode and the second electrode; and a crystal layer on the second electrode, wherein the second electrode is located between the crystal layer and the organic light-emitting layer, and the material of the crystal layer comprises 3) a compound represented, and the crystal layer has a rough surface The organic light-emitting device of claim 11, wherein the crystalline layer has a maximum thickness of less than 1 um. The organic light-emitting device of claim 11, wherein the first electrode comprises a reflective electrode, and the second electrode comprises a penetrating electrode. The organic light-emitting device of claim 11, further comprising a buffer layer between the second electrode and the crystal layer. The organic light-emitting element of claim 11, wherein the rough surface is a light-emitting surface.