Top-emitting organic light emitting diode based on amorphous metal

Abstract

The present disclosure relates to an organic light emitting diode (OLED) including a first electrode as an amorphous metal electrode. A first transport layer is on the first electrode, an emission layer is on the first transport layer, a second transport layer is on the emission layer, and a second electrode is on the second transport layer. The amorphous metal electrode provides a smooth, uniform surface such that the first transport layer, the emission layer, the second transport layer, and the second electrode are also uniformly formed.

Description

Technical Field

[0001] The present disclosure relates to organic light emitting diodes having amorphous metals. Background Art

[0002] Organic light emitting diodes (OLEDs) are commonly used to construct displays for electronic devices such as computers, monitors, televisions, flat panel displays, and mobile devices. OLEDs typically have a stack of layers including an organic emission layer between an anode and a cathode. The organic emission layer emits light in response to an electrical signal applied to the organic emission layer via the anode and cathode. OLEDs typically have a bottom emission structure or a top emission structure.

[0003] A bottom-emitting OLED includes a transparent anode as the bottom electrode of the OLED stack. In this case, light is transmitted from the emission layer and 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 transmitted from the emission layer and through the transparent cathode. Light is also reflected from the reflective anode and through the transparent cathode. A top-emitting OLED can also be inverted, where the OLED stack includes a reflective cathode as the bottom electrode and a transparent anode as the top electrode. In this case, light is transmitted from the emission layer and through the transparent anode. Light is also reflected from the reflective cathode and 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 carries 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. Utilizing more area of ​​a pixel results 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. Therefore, the electrodes typically have a rough, uneven surface. When 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 the top emission OLED and the reflective cathode of the inverted top emission OLED) is particularly important because the rough surface causes irregularities in the organic emission layer deposited on the hole injection electrode. Irregularities in the organic emission layer may cause significant negative effects on the OLED itself, such as degradation and dark spot formation. Summary of the invention

[0006] The present disclosure relates to organic light emitting diodes (OLEDs) having one or more amorphous metal electrodes. The amorphous metal electrodes provide a smooth, uniform surface for subsequent layers to be formed on the amorphous metal electrodes. The OLEDs may 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 emission layer on the hole transport layer, an electron transport layer on the organic emission layer, and a cathode on the electron transport layer. The anode is a reflective amorphous metal with a high work function (e.g., between 4.5 eV and 5 eV), and the cathode is transparent and has a low work function (e.g., between 4 eV and 4.4 eV).

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

[0009] Various other layers may also be included in OLEDs, such as injection layers and barrier layers. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] In the drawings, the same reference numerals indicate similar features or elements. The sizes and relative positions of features in the drawings are not necessarily drawn to scale.

[0011] Figure 1 is a cross-sectional view of an organic light emitting diode having an amorphous anode according to embodiments disclosed herein.

[0012] Figure 2 is the surface of the metal layer according to embodiments disclosed herein.

[0013] Figure 3 is the surface of the amorphous metal layer according to embodiments disclosed herein.

[0014] Figure 4 is a cross-sectional view of an organic light emitting diode having an amorphous cathode according to embodiments disclosed herein.

[0015] Figure 5 is a cross-sectional view of an organic light emitting diode according to an embodiment disclosed herein.

[0016] Figure 6 is a cross-sectional view of an organic light emitting diode according to an embodiment disclosed herein.

[0017] Figure 7 is a cross-sectional view of an organic light emitting diode according to an embodiment disclosed herein.

[0018] Figure 8 is a cross-sectional view of an organic light emitting diode according to an embodiment disclosed herein. DETAILED DESCRIPTION

[0019] In the following description, certain specific details are set forth 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, the structures and manufacturing and operating methods of well-known electronic components and organic light emitting diodes (OLEDs) are not described in detail to avoid obscuring the description of other aspects of the present disclosure.

[0020] Unless the context requires otherwise, throughout the specification and the appended claims, the word "comprise" and variations thereof (such as "include" and "comprising") should be interpreted as having an open, inclusive meaning, ie, "including, but not limited to."

[0021] References throughout the specification to "one embodiment" or "an embodiment" mean that a particular feature, structure, or characteristic described in conjunction with the embodiment is included in at least one embodiment. Therefore, the phrases "in one embodiment" or "in an embodiment" appearing in various places throughout the specification do not necessarily all refer to the same aspect. In addition, in one or more aspects of the present disclosure, particular features, structures, or characteristics may be combined in any suitable manner.

[0022] As mentioned above, the surface morphology of metals (such as aluminum (Al) and indium tin oxide (ITO) commonly used for electrodes of OLEDs is difficult to control during manufacturing and typically has a rough, uneven surface. When subsequent layers are deposited on the rough surface of the electrode, the surface morphology of the electrode causes the subsequent layers to have a rough, uneven surface. Such irregularities in the organic emission layer are particularly detrimental because they can cause degradation and dark spot formation in the OLED.

[0023] The present disclosure relates to OLEDs having one or more amorphous metal electrodes and methods for making the same. 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 emission layers) are uniformly formed on the amorphous metal electrodes, and degradation and dark spot formation in the OLED are minimized.

[0024] Figure 1OLED 10 is a cross-sectional view of an OLED 10 having an amorphous anode according to an embodiment disclosed herein. OLED 10 is a top-emitting OLED. OLED 10 includes substrate 12, anode 14, hole transport layer 16, organic emission layer 18, electron transport layer 20, and cathode 22.

[0025] Substrate 12 provides a support layer for anode 14, hole transport layer 16, organic emissive 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 and made of, for example, glass. The substrate can be any suitable transparent material, such as plastic. In addition, the substrate can be bendable, flexible, or non-rigid so that the resulting display can be rolled or bent without damaging the electronic components.

[0026] In one embodiment, if Figure 1 As shown in , substrate 12 may include circuitry 24 for OLED 10. Circuitry 24 may include various electronic components (e.g., resistors, transistors, capacitors, etc.), electrical connections, addressing circuits, and drive circuits for OLED 10. Circuitry 24 may also be fabricated on another substrate and electrically coupled to OLED 10 through electrical connections.

[0027] Anode 14 is formed on substrate 12. Anode 14 is a 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 an anode electrode of OLED 10, which is positively charged by, for example, circuit 24, so as to inject holes into organic emission layer 18.

[0028] Anode 14 is made of a reflective material and reflects light generated by organic emission layer 18 back to organic emission layer 18 and away from cathode 22. Anode 14 also has a high work function. For example, the work function represents the energy used to remove electrons from a metal. In one embodiment, anode 14 has a work function between 4.5 electron volts (eV) and 5 electron volts (eV).

[0029] Anode 14 is made of an amorphous metal. Amorphous metals are rigid solid materials whose atomic structures lack the periodicity that characterizes crystalline materials. In amorphous metals, the formation of crystal planes is suppressed, for example, by introducing multiple components. Alternatively, this can be achieved through a binary system. Amorphous metals are typically formed by rapid quenching from a metal melt or by rapid quenching from a plasma through physical vapor deposition (i.e., sputtering). Having more elements can help achieve a slower quenching rate of the melt; however, when physical vapor deposition (PVD) of a plasma is used, the quenching rate may be high enough that multiple elements are not so critical. Even in a binary system, the elements can have very different sizes. An example of an amorphous metal with four components is Zr, which includes zirconium, copper, aluminum, and nickel. 55 Cu 30 Al 10 Ni 5 .

[0030] Amorphous metals can be identified by their resistivity measurements, which have shown that amorphous metallic materials, while still conductive, have a resistivity approximately 10 times higher than their crystalline counterparts. Furthermore, amorphous metals are ideal for electrodes of OLEDs used in flexible OLED displays because of their inherent strength and flexibility.

[0031] In addition, 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 has a work function of approximately 1.5 eV. 40 W 40 Si 10 B 10 With a work function of approximately 4.1, amorphous metal TiAl 3 With a work function of approximately 4.3, amorphous metal Zr 40 Cu 35 Al 15 Ni 10 has a work function of approximately 4.7. Thus, as will be discussed in further detail below, amorphous metals can also be used in cathodes, which generally have a low work function.

[0032] Amorphous metals also have smoother surfaces than crystalline metals, as shown by surface roughness measurements. Figure 2 is a surface of a metal layer according to embodiments disclosed herein, and Figure 3 is the surface of the amorphous metal layer according to embodiments disclosed herein. Figure 2 The metal layer in is aluminum, and Figure 3 The amorphous metal layer in the 3 . Figure 2 and Figure 3 The surface shown in is shown in micrometers along the y-axis, in micrometers along the x-axis, and in meters along the z-axis.

[0033] Compare Figure 2 and Figure 3 , it can be seen that the amorphous metal layer provides a smoother uniform surface compared to the metal layer. For example, Figure 2 The metal layer in has an RMS roughness greater than 3 nm. Figure 3 The amorphous metal layer in the embodiment has a root mean square roughness of less than 1 nanometer.

[0034] The use of amorphous metal for anode 14 provides a smooth, flexible base layer for building subsequent layers (hole transport layer 16, organic emission layer 18, electron transport layer 20, and cathode 22). As a result, subsequent layers are uniformly formed on the amorphous metal surface, and degradation and dark spot formation in OLED 10 are minimized. This also enables the realization of a device including OLED 10 with improved reliability and a flexible OLED display with a higher aperture ratio.

[0035] In one embodiment, anode 14 has a root mean square roughness between 0.5 nanometers and 1 nanometer.

[0036] In one embodiment, the anode 14 includes an amorphous metal Zr 40 Cu 35 Al 15 Ni 10 It is also possible to use materials other than Zr 40 Cu 35 Al 15 Ni 10 Amorphous metals and other materials combined with these amorphous metals to better tune the electrode surface properties. Typically, mixing and matching of materials is done with the cathode to reduce the effective work function of the cathode, but not with the anode.

[0037] The hole transport layer 16 is formed on the anode 14. The hole transport layer 16 transports holes from the anode 14 and transports the holes to the organic emission layer 18.

[0038] The organic emission layer 18 is formed on the anode 14. The organic emission layer 18 converts the electrical energy generated by the holes from the anode 14 into light. The organic emission layer 18 is made of, for example, a host material plus a dopant to control a specific color. For example, the organic emission layer 18 can emit red light, green light, blue light, or white light, depending on the application of the OLED 10.

[0039] The electron transport layer 20 is formed on the organic emission layer 18. The electron transport layer 20 transports electrons from a cathode 22, which will be discussed below, to the organic emission layer 18.

[0040] The cathode 22 is formed on the electron transport layer 20. The cathode 22 is a cathode electrode of the OLED 10, which is negatively charged by, for example, a circuit 24, so as to inject electrons into the organic emission layer 18.

[0041] In contrast to the anode 14, the cathode 22 is made of a transparent material so that the light 26 generated by the organic emission layer 18 is emitted through the electron transport layer 20 and emitted from the cathode 22. In addition, the cathode 22 has a low work function. In one embodiment, the cathode 22 has a work function between 4 eV and 4.4 eV.

[0042] Metals with low work functions are generally more chemically reactive and less stable. Due to this instability, in some embodiments, cathode 22 is coated with a less reactive, slightly higher work function material such as aluminum.

[0043] Anode 14 and cathode 22 may be made of the same or different materials. Figure 1 In the embodiment shown in , both anode 14 and cathode 22 are amorphous metals as discussed above. As another example, anode 14 is an amorphous metal as discussed above; and cathode 22 is not an amorphous metal, such as aluminum, magnesium, silver, lithium fluoride, and indium tin oxide.

[0044] As mentioned above, amorphous metals have a wide range of work functions. For example, amorphous calcium aluminate has a work function of approximately 3 eV, amorphous zinc silicate has a work function of approximately 3.5 eV, and amorphous metal Ta has a work function of approximately 1.5 eV. 40 W 40 Si 10 B 10 With a work function of approximately 4.1, amorphous metal TiAl 3 With a work function of approximately 4.3, amorphous metal Zr 40 Cu 35 Al 15 Ni 10 With a work function of approximately 4.7, amorphous metals can also be used for cathodes, which generally have a low work function.

[0045] Figure 4 is a cross-sectional view of an OLED 28 having an amorphous cathode according to embodiments disclosed herein. Figure 1Similar to OLED 10 in FIG. 1 , OLED 28 includes substrate 12, anode 14, hole transport layer 16, organic emission layer 18, electron transport layer 20, and cathode 22. In addition, anode 14 has a high work function (e.g., between 4.5 eV and 5 eV), and cathode 22 has a low work function (e.g., between 4 eV and 4.4 eV).

[0046] In contrast to OLED 10, OLED 28 is an inverted top-emitting OLED, and the layers on substrate 12 are inverted. In other words, cathode 22 is formed on substrate 12, electron transport layer 20 is formed on cathode 22, organic emission layer 18 is formed on electron transport layer 20, hole transport layer 16 is formed on organic emission layer 18, and anode 14 is formed on hole transport layer 16. In this way, light 26 is generated by organic emission layer 18 and is emitted through hole transport layer 16 and emitted from anode 14. In this embodiment, cathode 22 is the bottom electrode and serves as a base for subsequent layers. In one embodiment, cathode 22 is in direct contact with substrate 12.

[0047] In addition, the cathode 22 in the OLED 28 is made of a reflective material, and reflects the light generated by the organic emission layer 18 back to the organic emission layer 18 and away from the anode 14. In addition, the cathode 22 is made of an amorphous metal. As discussed above, the amorphous metal is used for the cathode 22 to provide a smooth, flexible base layer to build subsequent layers (electron transport layer 20, organic emission layer 18, hole transport layer 16, and anode 14). As a result, the subsequent layers are uniformly formed on the amorphous metal surface, and the degradation and dark spot formation in the OLED 28 are minimized.

[0048] In one embodiment, cathode 22 comprises an amorphous metal TiAl 3 , amorphous metal Ta 40 Si 40 W 10 B 10 Or a combination thereof. Other than TiAl 3 and Ta 40 Si 40 W 10 B 10 Amorphous metals and other materials combined with amorphous metals can be used to better adjust the surface properties of the cathode, such as the electrode work function. For example, in one embodiment, a capping layer is formed between the cathode 22 and the electron transport layer 20. The capping layer may include one of lithium fluoride (LiF), amorphous calcium aluminate electrons, amorphous zinc silicate, or a combination thereof.

[0049] Also in contrast to OLED 10 , anode 14 in OLED 28 is made of a transparent material so that light 26 generated by organic emissive layer 18 is emitted through hole transport layer 16 and out of anode 14 .

[0050] As discussed above, anode 14 and cathode 22 may be made of the same or different materials. Figure 4 In the embodiment shown in , anode 14 and cathode 22 can both be amorphous metals as discussed above. As another example, cathode 22 is an amorphous metal; and anode 14 is not an amorphous metal, such as aluminum, magnesium, silver, lithium fluoride, and indium tin oxide.

[0051] Amorphous metal OLEDs (such as OLED 10 and OLED 28 discussed above) are not limited to specific materials, specific layer combinations, or specific material thicknesses for any of the functional layers placed on the base amorphous metal anode or cathode. The specific materials and thicknesses selected for the anode, hole transport layer, organic emission layer, electron transport layer, and cathode discussed above depend on the application (e.g., flat panel displays, lighting, flexible displays, etc.). Amorphous metal OLEDs may also include additional functional layers (such as injection layers and barrier layers) to enhance performance.

[0052] The following Figures 5 to 8 Examples of other OLEDs including underlying amorphous metal anodes or cathodes are shown.

[0053] Figure 5 is a cross-sectional view of an OLED 30 according to an embodiment disclosed herein. Figure 1 Similar to OLED 10 in FIG. 1 , OLED 30 is a top-emitting OLED and includes substrate 12, anode 14, hole transport layer 16, organic emission layer 18, electron transport layer 20, and cathode 22. In addition, anode 14 is a reflective amorphous metal with a high work function (e.g., between 4.5 eV and 5 eV), and cathode 22 is transparent and has a low work function (e.g., between 4 eV and 4.4 eV).

[0054] Compared with the OLED 10 , the OLED 30 includes a hole injection layer 32 and an electron injection layer 34 .

[0055] The hole injection layer 32 is formed between the anode 14 and the hole transport layer 16. The hole injection layer 32 improves the injection efficiency of holes from the anode 14 to the hole transport layer 16.

[0056] The electron injection layer 34 is formed between the electron transport layer 20 and the cathode 22. The electron injection layer 34 improves the injection efficiency of electrons from the cathode 22 to the electron transport layer 20.

[0057] In one embodiment, reference Figure 5 In the OLED 30 shown in FIG. 1 , the substrate 12 comprises glass; the anode 14 comprises an amorphous metal Zr 40 Cu 35 Al 15 Ni 10 The hole injection layer 32 includes a non-stoichiometric molybdenum oxide (MoO x ); the hole transport layer 16 includes N,N'-di(1-naphthyl)-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine (NPD); the organic emission layer 18 includes tris[2-phenylpyridine-C 2 ,N] iridium (III) (CPB:Ir(ppy)3) 4,4'-bis(N-carbazolyl)-1,1'-biphenyl, which acts as a white light emitter; the electron transport layer 20 includes tris-(8-hydroxyquinoline)aluminum (Alq); the electron injection layer 34 includes a first sublayer having amorphous zinc silicate (a-ZSO) and a second sublayer having amorphous calcium aluminate electron compound (a-C12A7:e); and the cathode 22 includes aluminum (Al).

[0058] In one embodiment, reference Figure 5 In the OLED 30 shown in , the substrate 12 has a thickness between 0.1 mm and 1.15 mm, the anode 14 has a thickness between 25 nm and 300 nm, the hole injection layer 32 has a thickness between 2 nm and 20 nm, the hole transport layer 16 has a thickness between 20 nm and 400 nm, the organic emission layer 18 has a thickness between 20 nm and 100 nm, the electron transport layer 20 has a thickness between 20 nm and 400 nm, the first sublayer of the electron injection layer 34 has a thickness between 20 nm and 75 nm, the second sublayer of the electron injection layer 34 has a thickness between 2 nm and 10 nm, and the cathode 22 has a thickness between 10 nm and 25 nm.

[0059] Figure 6 is a cross-sectional view of an OLED 36 according to an embodiment disclosed herein. Figure 4 OLED 36 is an inverted top-emitting OLED similar to OLED 28 in FIG. 1 ; and includes substrate 12, cathode 22, electron transport layer 20, organic emissive layer 18, hole transport layer 16, and anode 14. In addition, cathode 22 is a reflective amorphous metal with a low work function (e.g., between 4 eV and 4.4 eV), and anode 14 is transparent and has a high work function (e.g., between 4.5 eV and 5 eV).

[0060] In contrast to OLED 28, OLED 36 includes hole injection layer 32 and electron injection layer 34 discussed above.

[0061] In one embodiment, reference Figure 6 In the OLED 36 shown in FIG. 1 , the substrate 12 comprises glass; the cathode 22 comprises an amorphous metal Ta 40 Si 40 W 10 B 10 The electron injection layer 34 includes a first sublayer having amorphous zinc silicate (a-ZSO) and a second sublayer having amorphous calcium aluminate (a-C12A7:e); the electron transport layer 20 includes tris-(8-hydroxyquinoline)aluminum (Alq); the organic emission layer 18 includes tris-(8-hydroxyquinoline)aluminum doped with 1,1,4,4-tetraphenyl-1,3-butadiene (Alq:TPB), which acts as a blue light emitter; the hole transport layer 16 includes N,N'-di(1-naphthyl)-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine (NPD); the hole injection layer 32 includes non-stoichiometric molybdenum oxide (MoO x ); the anode 14 includes indium tin oxide (ITO).

[0062] In one embodiment, reference Figure 6 In the OLED 36 shown in , the substrate 12 has a thickness between 0.1 mm and 1.15 mm, the cathode 22 has a thickness between 25 nm and 300 nm, the first sublayer of the electron injection layer 34 has a thickness between 20 nm and 75 nm, the second sublayer of the electron injection layer 34 has a thickness between 2 nm and 10 nm, the electron transport layer 20 has a thickness between 20 nm and 400 nm, the organic emission layer 18 has a thickness between 20 nm and 100 nm, the hole transport layer 16 has a thickness between 20 nm and 400 nm, the hole injection layer 32 has a thickness between 2 nm and 20 nm, and the anode 14 has a thickness between 25 nm and 200 nm.

[0063] Figure 7 is a cross-sectional view of an OLED 38 according to an embodiment disclosed herein. Figure 4 OLED 38 is similar to OLED 28 in , and is an inverted top-emitting OLED; and includes substrate 12, cathode 22, electron transport layer 20, organic emission layer 18, hole transport layer 16, and anode 14. In addition, cathode 22 is a reflective amorphous metal with a low work function (e.g., between 4 eV and 4.4 eV), and anode 14 is transparent and has a high work function (e.g., between 4.5 eV and 5 eV).

[0064] Compared to OLED 28, OLED 38 includes the hole injection layer 32 and electron injection layer 34 discussed above. In addition, hole injection layer 32 and hole transport layer 16 are implemented with the same layer, and electron injection layer 34 and electron transport layer 20 are implemented with the same layer. In other words, the same material can be used as hole injection layer 32 and hole transport layer 16, and the same material can be used as electron injection layer 34 and electron transport layer 20.

[0065] Furthermore, OLED 38 includes a hole blocking layer 40 and an electron blocking layer 42 .

[0066] The hole blocking layer 40 is formed between the electron transport and injection layer 20 / 34 and the organic emission layer 18. The hole blocking layer 40 limits charge carriers from reaching the organic emission layer 18.

[0067] The electron blocking layer 42 is formed between the organic emission layer 18 and the hole transport and injection layer 16 / 32 . The electron blocking layer 42 restricts charge carriers from reaching the organic emission layer 18 .

[0068] In one embodiment, reference Figure 7 In the OLED 38 shown in FIG. 1 , the substrate 12 comprises glass; the cathode 22 comprises an amorphous metal TiAl 3 The electron transport and injection layer 20 / 34 includes 4,7-diphenyl-1,10-phenanthroline doped with Cs (BPhen:Cs); the hole blocking layer 40 includes 4,7-diphenyl-1,10-phenanthroline (BPhen); the organic emission layer 18 includes iridium (III) bis (2-methyldibenzo-[f,h]quinoxaline) (acetylacetone) (α-NPD:Ir(MDQ) doped with 2 (acac)), which acts as a white light emitter; the electron blocking layer 42 includes 2,2'-dimethyl-N,N'-di-[(1-naphthyl)-N,N'-diphenyl]-1,1'-biphenyl-4,4'-diamine (α-NPD); the hole transport and injection layer 16 / 32 includes N,N,N',N'-tetrakis(4-methoxyphenyl)-benzidine doped with Novaled dopant p-type 2 (MeO-TBD+NDP-2); and the anode 14 includes gold (Au).

[0069] In one embodiment, reference Figure 7In the OLED 38 shown in , the substrate 12 has a thickness between 0.1 mm and 1.15 mm, the cathode 22 has a thickness between 25 nm and 300 nm, the electron transport and injection layer 20 / 34 has a thickness between 20 nm and 400 nm, the hole blocking layer 40 has a thickness between 20 nm and 100 nm, the organic emission layer 18 has a thickness between 20 nm and 100 nm, the electron blocking layer 42 has a thickness between 20 nm and 100 nm, the hole transport and injection layer 16 / 32 has a thickness between 20 nm and 400 nm, and the anode 14 has a thickness between 10 nm and 25 nm.

[0070] Figure 8 is a cross-sectional view of an OLED 44 according to an embodiment disclosed herein. Figure 6 OLED 44 is an inverted top-emitting OLED similar to OLED 36 in FIG. 1 ; and includes substrate 12, cathode 22, electron injection layer 34, electron transport layer 20, organic emission layer 18, hole transport layer 16, hole injection layer 32, and anode 14. In addition, cathode 22 is a reflective amorphous metal with a low work function (e.g., between 4 eV and 4.4 eV), and anode 14 is transparent and has a high work function (e.g., between 4.5 eV and 5 eV).

[0071] Compared to the OLED 36, the organic emission layer 18 of the OLED 44 includes a first sublayer 46, a second sublayer 48, and a third sublayer 50. In addition, the anode 14 is made of an amorphous metal.

[0072] In one embodiment, reference Figure 8 In the OLED 44 shown in FIG. 4 , the substrate 12 comprises glass; the cathode 22 comprises an amorphous metal TiAl 3 The electron injection layer 34 includes lithium fluoride (LiF); the electron transport layer 20 includes 3-(4-biphenyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (TAZ); the first sublayer 46 includes a doped bis(2,4-diphenylquinolyl-N,C 2 ')iridium(acetylacetonate)(mCP:(PPQ) 2 Ir(acac))-doped 1,3-bis(9-carbazolyl)benzene, which acts as a red light emitter; the second sublayer 48 includes tris[2-phenylpyridine-C 2 ,N]iridium(III)(mCP:Ir(ppy) 3 ) of 1,3-bis(9-carbazolyl)benzene, which acts as a green light emitter; the third sublayer 50 includes bis[(4,6-difluorophenyl)-pyridyl-N,C 2'] 1,3-bis(9-carbazolyl)benzene of iridium(III) picolinate (mCP:Firpic), which acts as a blue light emitter; the hole transport layer 16 includes 4,4-bis(N-(1-naphthyl)-N-phenylamino)biphenyl (NPB); the hole injection layer 32 includes non-stoichiometric molybdenum oxide (MoO x ); Anode 14 includes amorphous metal Zr 40 Cu 35 Al 15 Ni 10 .

[0073] In one embodiment, reference Figure 8 In the OLED 44 shown in , the substrate 12 has a thickness between 0.1 mm and 1.15 mm, the cathode 22 has a thickness between 25 nm and 300 nm, the electron injection layer 34 has a thickness between 2 nm and 20 nm, the electron transport layer 20 has a thickness between 20 nm and 400 nm, the first sublayer 46 has a thickness between 20 nm and 100 nm, the second sublayer 48 has a thickness between 20 nm and 100 nm, the third sublayer 50 has a thickness between 20 nm and 100 nm, the hole transport layer 16 has a thickness between 20 nm and 400 nm, the hole injection layer 32 has a thickness between 2 nm and 20 nm, and the anode 14 has a thickness between 10 nm and 25 nm.

[0074] The layers of the OLED discussed herein may not be different materials. For example, a single material may be used as both an electron transport layer and an organic emissive layer. Alternatively, one or more materials may be used to form a single layer.

[0075] The present disclosure focuses on top-emitting OLEDs and inverted top-emitting OLEDs with amorphous metal electrodes because amorphous metal electrodes are particularly useful for structures having a stack of layers formed on the electrodes. However, the amorphous metal electrodes discussed herein can be used in other types of OLEDs including stacked layers formed on top of the electrodes.

[0076] Various embodiments disclosed herein provide OLEDs having one or more amorphous metal electrodes and methods of making the same. The amorphous metal electrodes provide a smooth, uniform surface, so that subsequent layers on the surface of the amorphous metal electrodes are also formed to be smooth and uniform.

[0077] The device can be summarized as including: a substrate; a first electrode on the substrate, the first electrode comprising an amorphous metal; a first transmission layer on the first electrode; an emission layer on the first transmission layer; a second transmission layer on the emission layer; and a second electrode on the second transmission layer.

[0078] The emission layer may be an organic emission layer.

[0079] The substrate may be a glass substrate.

[0080] 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.

[0081] The anode may be reflective and the cathode may be transparent.

[0082] The anode may have a first work function, and the cathode may have a second work function that may be smaller than the first work function.

[0083] Amorphous metals may include Zr 40 Cu 35 Al 15 Ni 10 .

[0084] 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.

[0085] The cathode may be reflective and the anode may be transparent.

[0086] The cathode may have a first work function, and the anode may have a second work function that may be greater than the first work function.

[0087] The amorphous metal may include a metal selected from the group consisting of Ta 40 Si 40 W 10 B 10 and TiAl 3 The materials in the material group.

[0088] The device may further include a cover layer between the first electrode and the first transmission layer.

[0089] The capping layer may include a material selected from the group consisting of lithium fluoride (LiF), amorphous calcium aluminate, and amorphous zinc silicate.

[0090] The second electrode may include an amorphous metal.

[0091] The device may also include: a first injection layer on the first electrode, the first transport layer on the first injection layer; and a second injection layer on the second transport layer, the second electrode on the second injection layer.

[0092] The first injection layer and the first transmission layer may be made of the same material, and the second injection layer and the second transmission layer may be made of the same material.

[0093] The first electrode may have a first thickness, and the second electrode may have a second thickness that is smaller than the first thickness.

[0094] The device may further include: a first barrier layer on the first transmission layer, the emission layer on the first barrier layer; and a second barrier layer on the emission layer, the second transmission layer on the second barrier layer.

[0095] A method can be summarized as including: forming a first electrode on a substrate, the first electrode comprising an amorphous metal; forming a first transmission layer on the first electrode; forming an emission layer on the first transmission layer; forming a second transmission layer on the emission layer; and forming a second electrode on the second transmission layer.

[0096] 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.

[0097] Amorphous metals may include Zr 40 Cu 35 Al 15 Ni 10 .

[0098] 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.

[0099] The amorphous metal may include a metal selected from the group consisting of Ta 40 Si 40 W 10 B 10 and TiAl 3 The materials in the material group.

[0100] An organic light emitting diode (OLED) can be summarized as including: a transparent substrate; a reflective electrode on the transparent substrate, the reflective electrode comprising an amorphous metal; a first transmission layer on the reflective electrode; an emission layer on the first transmission layer; a second transmission layer on the emission layer; and a transparent electrode on the second transmission layer.

[0101] The reflective 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 transparent electrode may be a cathode.

[0102] Amorphous metals may include Zr 40 Cu 35 Al 15 Ni 10 .

[0103] The reflective 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 transparent electrode may be an anode.

[0104] The amorphous metal may include a metal selected from the group consisting of Ta 40 Si 40 W 10 B 10 and TiAl 3 The materials in the material group.

[0105] The reflective electrode may have a root mean square roughness between 0.5 nanometers and 1 nanometer.

[0106] The reflective electrode may be in direct contact with the transparent substrate.

[0107] The various embodiments described above can be combined to provide further embodiments. These and other changes can be made to the embodiments according to the above detailed description. Generally, in the appended claims, the terms used should not be interpreted as limiting the claims to the specific embodiments disclosed in the specification and claims, but should be interpreted as including all possible embodiments and the full range of equivalents given by these claims. Therefore, the claims are not limited by this disclosure.

Claims

1. A device, include: substrate; a first electrode, on the substrate, the first electrode comprising an amorphous metal; a first transmission layer, on the first electrode; A transmission layer, on the first transmission layer; a second transmission layer, on the transmission layer; as well as The second electrode is on the second transmission layer.

2. The device according to claim 1, in, The emission layer is an organic emission layer.

3. The device according to claim 1, in, The substrate is a glass substrate.

4. The device according to claim 1, in, The first electrode is an anode, The first transport layer is a hole transport layer, The second transport layer is an electron transport layer, and The second electrode is a cathode.

5. The device according to claim 4, in, The anode is reflective and the cathode is transparent.

6. The device according to claim 4, in, The anode has a first work function, and the cathode has a second work function that is smaller than the first work function.

7. The device according to claim 4, in, The amorphous metal includes Zr 40 Cu 35 Al 15 Ni 10 .

8. The device according to claim 1, in, The first electrode is a cathode, The first transport layer is an electron transport layer, The second transport layer is a hole transport layer, and The second electrode is an anode.

9. The device according to claim 8, in, The cathode is reflective and the anode is transparent.

10. The device according to claim 8, in, The cathode has a first work function, and the anode has a second work function greater than the first work function.

11. The device according to claim 8, in, The amorphous metal includes Ta 40 Si 40 W 10 B 10 and TiAl 3 The materials in the material group.

12. The device according to claim 8, further comprising: include: A covering layer is between the first electrode and the first transmission layer.

13. The device according to claim 12, in, The capping layer includes a material selected from the group consisting of lithium fluoride (LiF), amorphous calcium aluminate, and amorphous zinc silicate.

14. The device according to claim 8, in, The second electrode includes an amorphous metal.

15. The device according to claim 1, further comprising: include: a first injection layer on the first electrode, wherein the first transport layer is on the first injection layer; as well as A second injection layer is on the second transport layer, and the second electrode is on the second injection layer.

16. The device according to claim 15, in, The first injection layer and the first transmission layer are made of the same material, and the second injection layer and the second transmission layer are made of the same material.

17. The device according to claim 1, in, The first electrode has a first thickness, and the second electrode has a second thickness that is smaller than the first thickness.

18. The device according to claim 1, further comprising: include: a first barrier layer on the first transmission layer, the emission layer on the first barrier layer; as well as A second blocking layer is on the emitting layer, and the second transmission layer is on the second blocking layer.

19. A method, include: forming a first electrode on a substrate, wherein the first electrode comprises an amorphous metal; forming a first transmission layer on the first electrode; forming an emission layer on the first transmission layer; forming a second transmission layer on the emission layer; as well as A second electrode is formed on the second transmission layer.

20. The method according to claim 19, in, The first electrode is an anode, The first transport layer is a hole transport layer, The second transport layer is an electron transport layer, and The second electrode is a cathode.

21. The method according to claim 20, in, The amorphous metal includes Zr 40 Cu 35 Al 15 Ni 10 .

22. The method according to claim 19, in, The first electrode is a cathode, The first transport layer is an electron transport layer, The second transport layer is a hole transport layer, and The second electrode is an anode.

23. The method according to claim 22, in, The amorphous metal includes Ta 40 Si 40 W 10 B 10 and TiAl 3 The materials in the material group.

24. An organic light emitting diode (OLED), include: Transparent substrate; a reflective electrode, on the transparent substrate, the reflective electrode comprising an amorphous metal; A first transmission layer, on the reflective electrode; A transmission layer, on the first transmission layer; a second transmission layer, on the transmission layer; as well as A transparent electrode is on the second transmission layer.

25. The OLED according to claim 24, in, The reflective electrode is an anode, The first transport layer is a hole transport layer, The second transport layer is an electron transport layer, and The transparent electrode is a cathode.

26. The OLED according to claim 25, in, The amorphous metal includes Zr 40 Cu 35 Al 15 Ni 10 .

27. The OLED according to claim 24, in, The reflective electrode is a cathode, The first transport layer is an electron transport layer, The second transport layer is a hole transport layer, and The transparent electrode is an anode.

28. The OLED according to claim 27, in, The amorphous metal includes Ta 40 Si 40 W 10 B 10 and TiAl 3 The materials in the material group.

29. The OLED according to claim 24, in, The reflective electrode has a root mean square roughness between 0.5 nanometers and 1 nanometer.

30. The OLED according to claim 24, in, The reflective electrode is in direct contact with the transparent substrate.

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