Amorphous metal-based top-emitting organic light-emitting diodes

Abstract

The present disclosure is directed to an organic light emitting diode (OLED) that includes a first electrode that is an amorphous metal electrode. A first transport layer is on the first electrode, an emissive layer is on the first transport layer, a second transport layer is on the emissive layer, and a second electrode is on the second transport layer. The amorphous metal electrode provides a smooth and uniform surface, which allows the first transport layer, the emissive layer, the second transport layer, and the second electrode to be formed uniformly.

Description

[Technical field]

[0001] The present disclosure is directed to organic light emitting diodes having amorphous metals. [Background technology]

[0002] Organic light-emitting diodes (OLEDs) are often used to form displays for electronic devices such as computers, monitors, televisions, tablets, and mobile devices. OLEDs generally have a stack of layers including an organic light-emitting layer disposed between an anode and a cathode. The organic light-emitting layer emits light in response to electrical signals applied to the organic light-emitting layer by the anode and cathode. OLEDs typically have either a bottom-emitting or a top-emitting structure.

[0003] A bottom-emitting OLED includes a transparent anode as the bottom electrode of the OLED stack. In this case, light is emitted from the light-emitting layer and passes through the transparent anode. In contrast, a top-emitting OLED includes a reflective anode as the bottom electrode of the OLED stack and a transparent cathode as the top electrode of the OLED stack. In this case, light is emitted from the light-emitting layer and passes through the transparent cathode. The light is also reflected from the reflective anode and passes through the transparent cathode. A top-emitting OLED may also be inverted, in which case the OLED stack includes a reflective cathode as the bottom electrode and a transparent anode as the top electrode. In this case, light is emitted from the light-emitting layer and passes through the transparent anode. The light is also reflected from the reflective cathode and passes through the transparent anode.

[0004] Top-emitting electrodes are particularly desirable for flat panel displays, such as active matrix OLED (AMOLED) displays, because light is emitted away from the substrate that contains the OLED stack and other circuitry on or in the substrate. This allows the OLED to utilize more of a given pixel area and have a larger aperture ratio. More pixel area is utilized, resulting in a brighter display for a given resolution, and higher resolution for a given brightness.

[0005] Various metals, such as aluminum (Al) and indium tin oxide (ITO), are commonly used as electrodes for OLEDs. However, the surface morphology of such metals is difficult to control during manufacturing. Thus, the electrodes often have rough and uneven surfaces. As subsequent layers are deposited on the electrodes, the surface morphology of the electrodes is directly transferred to the surface morphology of the subsequent layers. The rough surface of the hole-injection electrode (e.g., the reflective anode of a top-emission OLED and the reflective cathode of an inverted top-emission OLED) is particularly important because it creates irregularities on the organic light-emitting layer that is deposited on the hole-injection electrode. Irregularities in the organic light-emitting layer can have significant adverse effects on the OLED itself, such as degradation and dark spot formation. Summary of the Invention

[0006] The present disclosure is directed to organic light-emitting diodes (OLEDs) having one or more amorphous metal electrodes that provide a smooth and uniform surface for subsequent layers formed over the amorphous metal electrodes. The OLEDs can be, for example, top-emitting OLEDs and inverted top-emitting OLEDs.

[0007] In a top-emission OLED, the OLED includes a substrate, an anode on the substrate, a hole transport layer on the anode, an organic light-emitting layer on the hole transport layer, an electron transport layer on the organic light-emitting layer, and a cathode on the electron transport layer. The anode is a reflective amorphous metal with a high work function (e.g., 4.5-5 eV) and the cathode is transparent and has a low work function (e.g., between 4-4.4 eV).

[0008] In an inverted top-emission OLED, the OLED includes a substrate, a cathode on the substrate, an electron transport layer on the cathode, an organic light-emitting layer on the electron transport layer, a hole transport layer on the organic light-emitting layer, and an anode on the hole transport layer. The cathode is a reflective amorphous metal with a low work function (e.g., between 4 and 4.4 eV) and the anode 14 is transparent and has a high work function (e.g., between 4.5 and 5 eV).

[0009] Various other layers may also be included in the OLED, such as injection layers and blocking layers.

[0010] BRIEF DESCRIPTION OF SOME FIGURES In the drawings, the same reference numbers indicate like features or elements. The sizes and relative positions of features in the drawings are not necessarily drawn to scale. [Brief description of the drawings]

[0011] [Figure 1] FIG. 2 is a cross-sectional view of an organic light-emitting diode having an amorphous anode according to one embodiment disclosed herein. [Diagram 2] 1 is a surface of a metal layer according to one embodiment disclosed herein. [Diagram 3] 1 is a surface of an amorphous metal layer according to one embodiment disclosed herein. [Figure 4] FIG. 2 is a cross-sectional view of an organic light-emitting diode having an amorphous cathode according to one embodiment disclosed herein. [Diagram 5] 1 is a cross-sectional view of an organic light emitting diode according to one embodiment disclosed herein. [Figure 6]1 is a cross-sectional view of an organic light emitting diode according to one embodiment disclosed herein. [Figure 7] 1 is a cross-sectional view of an organic light emitting diode according to one embodiment disclosed herein. [Figure 8] 1 is a cross-sectional view of an organic light emitting diode according to one embodiment disclosed herein. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] In the following description, certain specific details are given to provide a thorough understanding of various aspects of the disclosed subject matter. However, the disclosed subject matter can be practiced without these specific details. In some cases, detailed descriptions of well-known structures and methods of manufacture and operation of electronic components and organic light-emitting diodes (OLEDs) are not given to avoid obscuring the description of other aspects of the present disclosure.

[0013] Unless the context requires otherwise, throughout the following specification and claims, the word "comprise" and variations thereof, such as "comprises" and "comprising," are to be interpreted in their open-ended and inclusive sense, i.e., "including but not limited to."

[0014] Throughout this specification, a reference to "one embodiment" or "one embodiment" means that a particular feature, structure, or characteristic described in connection with that embodiment is included in at least one embodiment. Thus, the appearances of the phrases "in one embodiment" or "in one embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Moreover, these particular features, structures, or characteristics may be combined in any suitable manner in one or more aspects of the disclosure.

[0015] As discussed above, the surface morphology of metals typically used in electrodes of OLEDs, such as aluminum (Al) and indium tin oxide (ITO), is difficult to control during manufacturing and often has a rough and uneven surface. When a subsequent layer is deposited on the rough surface of the electrode, the surface morphology of the electrode causes the subsequent layer to have a rough and uneven surface. Such irregularities in the organic light-emitting layer are particularly detrimental because they can cause degradation and dark spot formation in the OLED.

[0016] The present disclosure is directed to OLEDs having one or more amorphous metal electrodes, and methods for their manufacture. The amorphous metal electrodes provide a smooth, uniform surface for subsequent layers subsequently formed on the amorphous metal electrodes. As a result, subsequent layers, such as organic light-emitting layers, are formed uniformly on the amorphous metal electrodes, minimizing degradation and dark spot formation in the OLED.

[0017] 1 is a cross-sectional view of an OLED 10 having an amorphous anode according to one embodiment disclosed herein. The OLED 10 is a top-emitting OLED. The OLED 10 includes a substrate 12, an anode 14, a hole-transporting layer 16, an organic light-emitting layer 18, an electron-transporting layer 20, and a cathode 22.

[0018] Substrate 12 provides a support layer for anode 14, hole transport layer 16, organic light emitting layer 18, electron transport layer 20, and cathode 22. In one embodiment, substrate 12 is a semiconductor substrate. In one embodiment, substrate 12 is transparent, for example made of glass. The substrate may be any suitable transparent material, such as plastic. Additionally, the substrate may be bendable, flexible, or otherwise non-rigid, so that the resulting display can be rolled or bent without damaging the electronic components.

[0019] 1, substrate 12 can include circuitry 24 for OLED 10. Circuitry 24 can include various electronic components (e.g., resistors, transistors, capacitors, etc.), electrical connections, addressing circuitry, and driving circuitry for OLED 10. Circuitry 24 can also be fabricated on a separate substrate and electrically coupled to OLED 10 by electrical connections.

[0020] Anode 14 is formed on substrate 12. Anode 14 is the bottom electrode and serves as a base for subsequent layers. In one embodiment, anode 14 is in direct contact with substrate 12. Anode 14 is, for example, the anode electrode of OLED 10, which is positively charged by circuitry 24 to inject holes into organic light-emitting layer 18.

[0021] Anode 14 is made of a reflective material such that light generated in organic light-emitting layer 18 is reflected back towards organic light-emitting layer 18 and out of cathode 22. Anode 14 also has a high work function. Work function indicates the amount of energy used to remove an electron from, for example, a metal. In one embodiment, anode 14 has a work function between 4.5 and 5 electron volts (eV).

[0022] The anode 14 is made of an amorphous metal. Amorphous metals are rigid solid materials whose atomic structure lacks the periodicity characteristic of crystalline materials. In amorphous metals, the formation of crystal planes is suppressed, for example, by the incorporation of multiple components. Alternatively, this can be achieved using a binary system. Amorphous metals are often formed by quenching from a metal melt or from a plasma by physical vapor deposition (i.e., sputtering). Having more elements can help slow the quenching rate from the melt, but when using physical vapor deposition (PVD) from a plasma, the quenching rate can be fast enough that the presence of multiple elements is not critical. Even in a binary system, the elements can have very different sizes. An example of an amorphous metal with four components is Zr. 55 Cu 30 Al 10Ni5, which contains zirconium, copper, aluminum, and nickel.

[0023] Amorphous metals can be distinguished by their resistivity measurements, which have shown that amorphous metal materials, while still conductive, have about 10 times the resistivity of their crystalline counterparts. Furthermore, amorphous metals are inherently strong and flexible, making them desirable for OLED electrodes used in flexible OLED displays.

[0024] Furthermore, amorphous metals have a wide range of work functions. For example, amorphous calcium aluminate electride has a work function of approximately 3 eV, amorphous zinc silicate has a work function of approximately 3.5 eV, and the amorphous metal Ta 40 W 40 S 10 B 10 has an approximate work function of 4.1, the amorphous metal TiAl3 has an approximate work function of 4.3, and the amorphous metal Zr 40 Cu 35 Al 15 Ni 10 has an approximate work function of 4.7. Thus, amorphous metals, which generally have low work functions, can also be used for the cathode, as discussed in more detail below.

[0025] Amorphous metals also have smoother surfaces than crystalline metals, as shown by surface roughness measurements. For example, FIG. 2 is a surface of a metal layer according to one embodiment disclosed herein, and FIG. 3 is a surface of an amorphous metal layer according to one embodiment disclosed herein. The metal layer in FIG. 2 is aluminum, and the amorphous metal layer in FIG. 3 is the amorphous metal TiAl3. The surfaces shown in FIG. 2 and 3 are shown along the y-axis in micrometers, the x-axis in micrometers, and the z-axis in meters.

[0026] Comparing Figures 2 and 3, it can be seen that the amorphous metal layer provides a much smoother and more uniform surface than the metal layer. For example, the metal layer in Figure 2 has a root mean square roughness of more than 3 nanometers. In contrast, the amorphous metal layer in Figure 3 has a root mean square roughness of less than 1 nanometer.

[0027] The use of amorphous metal for anode 14 provides a smooth and flexible base layer on which to form subsequent layers (hole transport layer 16, organic light-emitting layer 18, electron transport layer 20, and cathode 22). As a result, subsequent layers are formed uniformly on the amorphous metal surface, minimizing degradation and dark spot formation in OLED 10. This can also improve the reliability of devices including OLED 10, and flexible OLED displays with larger aperture ratios.

[0028] In one embodiment, anode 14 has a root mean square roughness between 0.5 and 1 nanometers.

[0029] In one embodiment, the anode 14 is made of amorphous metal, Zr 40 Cu 35 Al 15 Ni 10 In order to better control the electrode surface properties, Zr 40 Cu 35 Al 15 Ni 10 Other amorphous metals may also be used, and other materials may be used in combination with the amorphous metal. Typically, materials are mixed and matched with the cathode to lower the effective work function of the cathode, but not the anode.

[0030] A hole transport layer 16 is formed on the anode 14. The hole transport layer 16 transports holes from the anode 14 to the organic light-emitting layer 18.

[0031] An organic light-emitting layer 18 is formed on the anode 14. The organic light-emitting layer 18 converts the electrical energy obtained by the holes from the anode 14 into light. The organic light-emitting layer 18 is made of, for example, a host material and a dopant to control a specific color. For example, the organic light-emitting layer 18 can emit red, green, blue, or white light depending on the application of the OLED 10.

[0032] An electron transport layer 20 is formed on the organic light-emitting layer 18. The electron transport layer 20 transports electrons to the organic light-emitting layer 18 from a cathode 22, which will be described below.

[0033] A cathode 22 is formed on the electron transport layer 20. Cathode 22 is, for example, a cathode electrode of OLED 10 that is negatively charged by circuit 24 to inject electrons into organic light-emitting layer 18.

[0034] In contrast to anode 14, cathode 22 is a transparent material so that light 26 generated by organic light-emitting layer 18 is emitted through electron transport layer 20 and out of cathode 22. Additionally, cathode 22 has a low work function. In one embodiment, cathode 22 has a work function between 4 and 4.4 eV.

[0035] Metals with low work functions are typically more chemically reactive and less stable, and because of this instability, in some embodiments, cathode 22 is coated with a less reactive, slightly higher work function material, such as aluminum.

[0036] The anode 14 and the cathode 22 may be made of the same or different materials. For example, in the embodiment shown in Figure 1, both the anode 14 and the cathode 22 are amorphous metals as discussed above. As another example, the anode 14 is an amorphous metal as discussed above, and the cathode 22 is a non-amorphous metal, such as aluminum, magnesium silver, lithium fluoride, and indium tin oxide.

[0037] As mentioned above, amorphous metals have a wide range of work functions. For example, amorphous calcium aluminate electride has a work function of approximately 3 eV, amorphous zinc silicate has a work function of approximately 3.5 eV, and amorphous metal Ta 40 W 40 S 10 B 10 has an approximate work function of 4.1, the amorphous metal TiAl3 has an approximate work function of 4.3, and the amorphous metal Zr 40 Cu 35 Al 15 Ni 10 has an approximate work function of 4.7. Therefore, amorphous metals, which generally have low work functions, can also be used for the cathode.

[0038] Figure 4 is a cross-sectional view of an OLED 28 having an amorphous cathode according to one embodiment disclosed herein. Similar to OLED 10 in Figure 1, OLED 28 includes substrate 12, anode 14, hole transport layer 16, organic light-emitting layer 18, electron transport layer 20, and cathode 22. Additionally, anode 14 has a high work function (e.g., between 4.5 and 5 eV) and cathode 22 has a low work function (e.g., between 4 and 4.4 eV).

[0039] In contrast to OLED 10, OLED 28 is an inverted top-emission OLED, in which the layers on substrate 12 are inverted. Stated another way, cathode 22 is formed on substrate 12, electron transport layer 20 is formed on cathode 22, organic light-emitting layer 18 is formed on electron transport layer 20, hole transport layer 16 is formed on organic light-emitting layer 18, and anode 14 is formed on hole transport layer 16. Light 26 is thus generated by organic light-emitting layer 18 and emitted through hole transport layer 16 and out of anode 14. In this embodiment, cathode 22 is the bottom electrode and serves as a foundation for subsequent layers. In one embodiment, cathode 22 in direct contact with substrate 12.

[0040] Additionally, the cathode 22 in the OLED 28 is made of a reflective material such that light generated by the organic light-emitting layer 18 is reflected back into the organic light-emitting layer 18 and out the anode 14. Additionally, the cathode 22 is made of an amorphous metal. As discussed above, the use of an amorphous metal for the cathode 22 provides a smooth and flexible base layer for forming subsequent layers (electron transport layer 20, organic light-emitting layer 18, hole transport layer 16, and anode 14). As a result, subsequent layers are formed uniformly on the amorphous metal surface, minimizing degradation and dark spot formation in the OLED 28.

[0041] In one embodiment, the cathode 22 is made of an amorphous metal, TiAl 3、 Amorphous metal Ta 40 S 40 W 10 B 10 or a combination thereof. In order to better tailor the surface properties of the cathode, such as the work function of the electrode, TiAl3 and Ta 40 S 40 W 10 B 10 Amorphous materials other than 10 ...

[0042] Also in contrast to OLED 10 , anode 14 in OLED 28 is made of a transparent material so that light 26 generated by organic light-emitting layer 18 is emitted through hole-transport layer 16 and out of anode 14 .

[0043] As discussed above, the anode 14 and the cathode 22 may be made of the same or different materials. For example, in the embodiment shown in Figure 4, both the anode 14 and the cathode 22 may be amorphous metals, as discussed above. As another example, the cathode 22 is an amorphous metal and the anode 14 is a non-amorphous metal, such as aluminum, magnesium silver, lithium fluoride, and indium tin oxide.

[0044] Amorphous metal OLEDs, such as OLED 10 and OLED 28 discussed above, are not limited to any particular material, combination of layers, or thickness of any particular material for any functional layer disposed on top of the underlying amorphous metal anode or cathode. The particular materials and thicknesses selected for the anode, hole transport layer, organic light emitting layer, electron transport layer, and cathode discussed above depend on the application (e.g., flat panel display, lighting, flexible display, etc.). Amorphous metal OLEDs can also include additional functional layers, such as injection layers and blocking layers, to improve performance.

[0045] Figures 5-8 below show other OLED examples that include underlying amorphous metal anodes or cathodes.

[0046] Figure 5 is a cross-sectional view of an OLED 30 according to one embodiment disclosed herein. Similar to OLED 10 in Figure 1, OLED 30 is a top-emission OLED and includes a substrate 12, an anode 14, a hole-transporting layer 16, an organic light-emitting layer 18, an electron-transporting layer 20, and a cathode 22. In addition, anode 14 is a reflective amorphous metal having a high work function (e.g., between 4.5 and 5 eV), and cathode 22 is transparent and has a low work function (e.g., between 4 and 4.4 eV).

[0047] In contrast to OLED 10, OLED 30 includes a hole-injection layer 32 and an electron-injection layer 34.

[0048] The hole injection layer 32 is formed between the anode 14 and the hole transport layer 16. The hole injection layer 32 improves the efficiency of injection of holes from the anode 14 into the hole transport layer 16.

[0049] The electron injection layer 34 is formed between the electron transport layer 20 and the cathode 22. The electron injection layer 34 improves the efficiency of injection of electrons from the cathode 22 into the electron transport layer 20.

[0050] In one embodiment, referring to the OLED 30 shown in FIG. 5, the substrate 12 comprises glass; the anode 14 comprises amorphous metallic Zr 40 Cu 35 Al 15 Ni 10 hole injection layer 32 comprises non-stoichiometric molybdenum oxide (MoO x the hole transport layer 16 comprises N,N'-di(1-naphthyl)-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine (NPD); the organic light emitting layer 18 comprises tris[2-phenylpyridinato-C 2 ,N]iridium(III) doped 4,4'-bis(N-carbazolyl)-1,1'-biphenyl (CPB:Ir(ppy)3); electron transport layer 20 comprises tris-(8-hydroxyquinoline)aluminum (Alq); electron injection layer 34 comprises a first sublayer having amorphous zinc silicate (a-ZSO) and a second sublayer having amorphous calcium aluminate electride (a-C12A7:e - and a second sublayer having a cathode 22 comprising aluminum (Al).

[0051] In one embodiment, referring to OLED 30 shown in FIG. 5, substrate 12 has a thickness between 0.1 and 1.15 millimeters, anode 14 has a thickness between 25 and 300 nanometers, hole injection layer 32 has a thickness between 2 and 20 nanometers, hole transport layer 16 has a thickness between 20 and 400 nanometers, organic light-emitting layer 18 has a thickness between 20 and 100 nanometers, electron transport layer 20 has a thickness between 20 and 400 nanometers, a first sublayer of electron injection layer 34 has a thickness between 20 and 75 nanometers, a second sublayer of electron injection layer 34 has a thickness between 2 and 10 nanometers, and cathode 22 has a thickness between 10 and 25 nanometers.

[0052] Figure 6 is a cross-sectional view of an OLED 36 according to one embodiment disclosed herein. Similar to OLED 28 in Figure 4, OLED 36 is an inverted top-emission OLED and includes a substrate 12, a cathode 22, an electron transport layer 20, an organic light-emitting layer 18, a hole transport layer 16, and an anode 14. Furthermore, cathode 22 is a reflective amorphous metal with a low work function (e.g., between 4 and 4.4 eV), and anode 14 is transparent and has a high work function (e.g., between 4.5 and 5 eV).

[0053] In contrast to OLED 28, OLED 36 includes hole-injection layer 32 and electron-injection layer 34, as discussed above.

[0054] In one embodiment, referring to the OLED 36 shown in FIG. 6, the substrate 12 comprises glass; the cathode 22 comprises an amorphous metal, Ta. 40 S 40 W 10 B 10 the electron injection layer 34 comprises a first sublayer having amorphous zinc silicate (a-ZSO) and a second sublayer having amorphous calcium aluminate electride (a-C12A7:e -the electron transport layer 20 comprises tris-(8-hydroxyquinoline)aluminum (Alq); the organic light emitting layer 18 comprises tris-(8-hydroxyquinoline)aluminum doped with 1,1,4,4-tetraphenyl-1,3-butadiene (Alq:TPB) which functions as a blue emitter; the hole transport layer 16 comprises N,N'-di(1-naphthyl)-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine (NPD); and the hole injection layer 32 comprises nonstoichiometric molybdenum oxide (MoO x anode 14 comprises indium tin oxide (ITO);

[0055] In one embodiment, referring to OLED 36 shown in FIG. 6, substrate 12 has a thickness between 0.1 and 1.15 millimeters, cathode 22 has a thickness between 25 and 300 nanometers, a first sublayer of electron injection layer 34 has a thickness between 20 and 75 nanometers, a second sublayer of electron injection layer 34 has a thickness between 2 and 10 nanometers, electron transport layer 20 has a thickness between 20 and 400 nanometers, organic light-emitting layer 18 has a thickness between 20 and 100 nanometers, hole transport layer 16 has a thickness between 20 and 400 nanometers, hole injection layer 32 has a thickness between 2 and 20 nanometers, and anode 14 has a thickness between 25 and 200 nanometers.

[0056] Figure 7 is a cross-sectional view of an OLED 38 according to one embodiment disclosed herein. Similar to OLED 28 in Figure 4, OLED 38 is an inverted top-emission OLED and includes a substrate 12, a cathode 22, an electron transport layer 20, an organic light-emitting layer 18, a hole transport layer 16, and an anode 14. Furthermore, cathode 22 is a reflective amorphous metal having a low work function (e.g., between 4 and 4.4 eV), and anode 14 is transparent and has a high work function (e.g., between 4.5 and 5 eV).

[0057] In contrast to OLED 28, OLED 38 includes the hole injection layer 32 and electron injection layer 34 discussed above. Additionally, the hole injection layer 32 and the hole transport layer 16 are realized in the same layer, and the electron injection layer 34 and the electron transport layer 20 are realized in the same layer. Stated another way, the same material can function as the hole injection layer 32 and the hole transport layer 16, and the same material can function as the electron injection layer 34 and the electron transport layer 20.

[0058] In addition, the OLED 38 includes a hole blocking layer 40 and an electron blocking layer 42 .

[0059] A hole blocking layer 40 is formed between the electron transport and injection layer 20 / 34 and the organic light emitting layer 18. The hole blocking layer 40 confines charge carriers to the organic light emitting layer 18.

[0060] The electron blocking layer 42 is formed between the organic light-emitting layer 18 and the hole transport and injection layer 16 / 32. The electron blocking layer 42 confines charge carriers to the organic light-emitting layer 18.

[0061] In one embodiment, referring to OLED 38 in FIG. 7, substrate 12 comprises glass; cathode 22 comprises amorphous metal TiAl3; electron transport and injection layer 20 / 34 comprises 4,7-diphenyl-1,10-phenanthroline doped with Cs (BPhen:Cs); hole blocking layer 40 comprises 4,7-diphenyl-1,10-phenanthroline (BPhen); organic light emitting layer 18 comprises 2,2'-dimethyl-N,N'-di-[(2-methyldibenzo-[f,h]quinoxaline)(acetylacetonato)iridium(III) doped with bis(2-methyldibenzo-[f,h]quinoxaline)(acetylacetonato)iridium(III) to function as a white light emitter. the electron blocking layer 42 comprises 2,2'-dimethyl-N,N'-di-[(1-naphthyl)-N,N'-diphenyl]-1,1'-biphenyl-4,4'-diamine (α-NPD:Ir(MDQ)2(acac)); the hole transporting and injection layer 16 / 32 comprises N,N,N',N'-tetrakis(4-methoxyphenyl)-benzidine doped with Novaled dopant p-type 2 (MeO-TBD+NDP-2); and the anode 14 comprises gold (Au).

[0062] In one embodiment, referring to OLED 38 in FIG. 7, substrate 12 has a thickness between 0.1 and 1.15 millimeters, cathode 22 has a thickness between 25 and 300 nanometers, electron transport and injection layer 20 / 34 has a thickness between 20 and 400 nanometers, hole blocking layer 40 has a thickness between 20 and 100 nanometers, organic light-emitting layer 18 has a thickness between 20 and 100 nanometers, electron blocking layer 42 has a thickness between 20 and 100 nanometers, hole transport and injection layer 16 / 32 has a thickness between 20 and 400 nanometers, and anode 14 has a thickness between 10 and 25 nanometers.

[0063] Figure 8 is a cross-sectional view of an OLED 44 according to one embodiment disclosed herein. Similar to OLED 36 in Figure 6, OLED 44 is an inverted top-emission OLED and includes substrate 12, cathode 22, electron injection layer 34, electron transport layer 20, organic light-emitting layer 18, hole transport layer 16, hole injection layer 32, and anode 14. Furthermore, cathode 22 is a reflective amorphous metal with a low work function (e.g., between 4 and 4.4 eV), and anode 14 is transparent and has a high work function (e.g., between 4.5 and 5 eV).

[0064] In contrast to OLED 36, organic light-emitting layer 18 of OLED 44 includes a first sublayer 46, a second sublayer 48, and a third sublayer 50. Furthermore, anode 14 is made of an amorphous metal.

[0065] In one embodiment, referring to the OLED 44 shown in FIG. 8, the substrate 12 comprises glass; the cathode 22 comprises the amorphous metal TiAl3; the electron injection layer 34 comprises lithium fluoride (LiF); the electron transport layer 20 comprises 3-(4-biphenyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (TAZ); the first sublayer 46 comprises bis(2,4-diphenylquinolyl-N,C) which functions as a red emitter; 2 The second sublayer 48 comprises 1,3-bis(9-carbazolyl)benzene doped with iridium(acetylacetonate) (mCP:(PPQ)2Ir(acac)); and the second sublayer 49 comprises tris[2-phenylpyridinato-C 2 , N]iridium(III) doped 1,3-bis(9-carbazolyl)benzene (mCP:Ir(ppy)3) which acts as a blue emitter; and the third sublayer 50 comprises bis[(4,6-difluorophenyl)-pyridinato-N,C 2 '] comprises 1,3-bis(9-carbazolyl)benzene doped with iridium(III) picolinate (mCP:Firpic); hole transport layer 16 comprises 4,4-bis(N-(1-naphthyl)-N-phenylamino)biphenyl (NPB); hole injection layer 32 comprises nonstoichiometric molybdenum oxide (MoO x) and the anode 14 comprises amorphous metallic Zr 40 Cu 35 Al 15 Ni 10 Includes.

[0066] In one embodiment, referring to the OLED 44 shown in FIG. 8, the substrate 12 has a thickness between 0.1 and 1.15 millimeters, the cathode 22 has a thickness between 25 and 300 nanometers, the electron injection layer 34 has a thickness between 2 and 20 nanometers, the electron transport layer 20 has a thickness between 20 and 400 nanometers, the first sublayer 46 has a thickness between 20 and 100 nanometers, the second sublayer 48 has a thickness between 20 and 100 nanometers, the third sublayer 50 has a thickness between 20 and 100 nanometers, the hole transport layer 16 has a thickness between 20 and 400 nanometers, the hole injection layer 32 has a thickness between 2 and 20 nanometers, and the anode 14 has a thickness between 10 and 25 nanometers.

[0067] The various layers of the OLEDs discussed herein do not have to be separate materials. For example, one material may function as both an electron transport layer and an organic light-emitting layer. Alternatively, one or more materials may be used to form one layer.

[0068] This disclosure focuses on top-emission OLEDs and inverted top-emission OLEDs with amorphous metal electrodes because amorphous metal electrodes are particularly useful in structures having a stack of layers formed on the electrode, however, the amorphous metal electrodes discussed herein can be used in other types of OLEDs that include a stack of layers formed on top of the electrode.

[0069] Various embodiments disclosed herein provide OLEDs, and methods for making same, having one or more amorphous metal electrodes that provide a smooth and uniform surface that allows subsequent layers formed on the surface of the amorphous metal electrode to also be smooth and uniform.

[0070] The device can be summarized as including a substrate; a first electrode on the substrate, the first electrode comprising an amorphous metal; a first transport layer on the first electrode; an emissive layer on the first transport layer; a second transport layer on the emissive layer; and a second electrode on the second transport layer.

[0071] The light-emitting layer may be an organic light-emitting layer.

[0072] The substrate may be a glass substrate.

[0073] The first electrode may be an anode, the first transport layer may be a hole transport layer, the second transport layer may be an electron transport layer, and the second electrode may be a cathode.

[0074] The anode may be reflective and the cathode may be transparent.

[0075] The anode can have a first work function and the cathode can have a second work function, which can be less than the first work function.

[0076] Amorphous metal is Zr 40 Cu 35 Al 15 Ni 10 may include.

[0077] The first electrode may be a cathode, the first transport layer may be an electron transport layer, the second transport layer may be a hole transport layer, and the second electrode may be an anode.

[0078] The cathode may be reflective and the anode may be transparent.

[0079] The cathode can have a first work function and the anode can have a second work function, which can be greater than the first work function.

[0080] The amorphous metal is Ta. 40 S 40 W 10 B 10and TiAl3.

[0081] The device may further include a capping layer between the first electrode and the first transport layer.

[0082] The capping layer may comprise a material selected from a group of materials including lithium fluoride (LiF), amorphous calcium aluminate electride, and amorphous zinc silicate.

[0083] The second electrode can include an amorphous metal.

[0084] The device may further include a first injection layer on the first electrode, with a first transport layer on the first injection layer; and a second injection layer on the second transport layer, with a second electrode on the second injection layer.

[0085] The first injection layer and the first transport layer may be made of the same material, and the second injection layer and the second transport layer may be made of the same material.

[0086] The first electrode can have a first thickness and the second electrode can have a second thickness that is less than the first thickness.

[0087] The device can further include: a first blocking layer on the first transport layer, with the emissive layer on the first blocking layer; and a second blocking layer on the emissive layer, with the second transport layer on the second blocking layer.

[0088] The method can be summarized as including: forming a first electrode on a substrate, the first electrode comprising an amorphous metal; forming a first transport layer on the first electrode; forming an emissive layer on the first transport layer; forming a second transport layer on the emissive layer; and forming a second electrode on the second transport layer.

[0089] The first electrode may be an anode, the first transport layer may be a hole transport layer, the second transport layer may be an electron transport layer, and the second electrode may be a cathode.

[0090] Amorphous metal is Zr 40 Cu 35 Al 15 Ni 10 may include.

[0091] The first electrode may be a cathode, the first transport layer may be an electron transport layer, the second transport layer may be a hole transport layer, and the second electrode may be an anode.

[0092] The amorphous metal is Ta. 40 S 40 W 10 B 10 and TiAl3.

[0093] An organic light emitting diode (OLED) can be summarized as comprising: a transparent substrate; a reflective electrode on the transparent substrate, the reflective electrode comprising an amorphous metal; a first transport layer on the reflective electrode; an emissive layer on the first transport layer; a second transport layer on the emissive layer; and a transparent electrode on the second transport layer.

[0094] The reflective electrode may be the anode, the first transport layer may be a hole transport layer, the second transport layer may be an electron transport layer, and the transparent electrode may be the cathode.

[0095] Amorphous metal is Zr 40 Cu 35 Al 15 Ni 10 may include.

[0096] The reflective electrode may be the cathode; the first transport layer may be an electron transport layer; the second transport layer may be a hole transport layer; and the transparent electrode may be the anode.

[0097] The amorphous metal is Ta. 40S 40 W 10 B 10 and TiAl3.

[0098] The reflective electrode can have a root-mean-square roughness of between 0.5 and 1 nanometer.

[0099] The reflective electrode can be in direct contact with the transparent substrate.

[0100] Various embodiments described above can be combined to obtain further embodiments. These and other changes can be made to the embodiments in light of the above detailed description. In general, the terms used in the following claims should not be construed to limit the claims to the specific embodiments disclosed in the specification and claims, but should be construed to include all possible embodiments along with the full scope of equivalents to which such claims are entitled. Thus, the claims are not limited by this disclosure.

Claims

1. A substrate; a first electrode on the substrate, the first electrode comprising an amorphous metal; a first transport layer on the first electrode; a light-emitting layer on the first transport layer; a second transport layer over the light-emitting layer; a second electrode on the second transport layer; and The device that contains

2. The device of claim 1 , wherein the light-emitting layer is an organic light-emitting layer.

3. The device of claim 1 , wherein the substrate is a glass substrate.

4. the first electrode is an anode; the first transport layer is a hole transport layer; the second transport layer is an electron transport layer; The device of claim 1 , wherein the second electrode is a cathode.

5. The device of claim 4 wherein the anode is reflective and the cathode is transparent.

6. The device of claim 4 , wherein the anode has a first work function and the cathode has a second work function less than the first work function.

7. The amorphous metal is Zr ４０ Cu ３５ A １５ Ni １０ The device of claim 4 , comprising:

8. the first electrode is a cathode; the first transport layer is an electron transport layer; the second transport layer is a hole transport layer; The device of claim 1 , wherein the second electrode is an anode.

9. The device of claim 8 wherein the cathode is reflective and the anode is transparent.

10. The device of claim 8 , wherein the cathode has a first work function and the anode has a second work function greater than the first work function.

11. The amorphous metal is Ta. ４０ S ４０ W １０ B １０ and TiAl ３ 9. The device of claim 8, comprising a material selected from the group of materials comprising:

12. The device of claim 8 further comprising a capping layer between the first electrode and the first transport layer.

13. 13. The device of claim 12, wherein the capping layer comprises a material selected from the group of materials including lithium fluoride (LiF), amorphous calcium aluminate electride, and amorphous zinc silicate.

14. The device of claim 8 , wherein the second electrode comprises an amorphous metal.

15. a first injection layer on the first electrode, the first transport layer being on the first injection layer; a second injection layer on the second transport layer, the second electrode being on the second injection layer; The device of claim 1 further comprising:

16. 16. The device of claim 15, wherein the first injection layer and the first transport layer are made of the same material, and the second injection layer and the second transport layer are made of the same material.

17. The device of claim 1 , wherein the first electrode has a first thickness and the second electrode has a second thickness that is less than the first thickness.

18. a first blocking layer on the first transport layer, the light-emitting layer being on the first blocking layer; a second blocking layer on the light-emitting layer, the second transport layer being on the second blocking layer; and The device of claim 1 further comprising:

19. forming a first electrode on a substrate, the first electrode comprising an amorphous metal; forming a first transport layer over the first electrode; forming a light emitting layer over the first transport layer; forming a second transport layer over the light emitting layer; forming a second electrode on the second transport layer; A method comprising:

20. the first electrode is an anode; the first transport layer is a hole transport layer; the second transport layer is an electron transport layer; 20. The method of claim 19, wherein the second electrode is a cathode.

21. The amorphous metal is Zr ４０ Cu ３５ A １５ Ni １０ 21. The method of claim 20, comprising:

22. the first electrode is a cathode; the first transport layer is an electron transport layer; the second transport layer is a hole transport layer; 20. The method of claim 19, wherein the second electrode is an anode.

23. The amorphous metal is Ta. ４０ S ４０ W １０ B １０ and TiAl ３ 23. The method of claim 22, comprising a material selected from the group of materials comprising:

24. A transparent substrate; a reflective electrode on the transparent substrate, the reflective electrode comprising an amorphous metal; a first transport layer on the reflective electrode; a light-emitting layer on the first transport layer; a second transport layer over the light-emitting layer; a transparent electrode on the second transport layer; An organic light emitting diode (OLED).

25. the reflective electrode is an anode, the first transport layer is a hole transport layer; the second transport layer is an electron transport layer; 25. The OLED of claim 24, wherein the transparent electrode is a cathode.

26. The amorphous metal is Zr ４０ Cu ３５ A １５ Ni １０ 26. The OLED of claim 25 comprising:

27. the reflective electrode is a cathode, the first transport layer is an electron transport layer; the second transport layer is a hole transport layer; 25. The OLED of claim 24, wherein the transparent electrode is an anode.

28. The amorphous metal is Ta. ４０ S ４０ W １０ B １０ and TiAl ３ 28. The OLED of claim 27, comprising a material selected from the group of materials comprising:

29. 25. The OLED of claim 24, wherein the reflective electrode has a root-mean-square roughness between 0.5 and 1 nanometer.

30. 25. The OLED of claim 24, wherein the reflective electrode is in direct contact with the transparent substrate.

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