Metal complex comprising novel ligand structures

Abstract

This invention provides compounds comprising metal complexes having novel ligands. Specifically, the compounds are iridium complexes comprising novel aza-DBX ligands. These compounds can be used in organic light-emitting devices (specifically as light-emitting dopants), providing improved performance, low operating voltage, and long lifespan.

Description

[Technical Field] This invention relates to organic materials applicable to organic light-emitting devices. More specifically, this invention relates to compounds comprising metal complexes having novel ligand structures and devices incorporating such compounds. [Previous Technology] Optoelectronic devices utilizing organic materials are becoming increasingly noteworthy for numerous reasons. Many materials suitable for manufacturing such devices are relatively inexpensive, thus giving optoelectronic devices a cost advantage over inorganic devices. Furthermore, the inherent properties of organic materials, such as their flexibility, make them highly suitable for specific applications, such as articles on flexible substrates. Examples of organic optoelectronic devices include organic light-emitting diodes (OLEDs), organic phototransistors, organic photovoltaic cells, and organic photodetectors. In the case of OLEDs, organic materials can offer performance advantages over conventional materials. For example, the wavelength of light emitted by an organic light-emitting layer can generally be easily tuned using suitable dopants. OLEDs utilize organic thin films that emit light when a voltage is applied across the device's terminals. OLEDs have become an increasingly superior technology for devices such as flat panel displays, lighting, and backlights. Several OLED materials and configurations are described in U.S. Patent Nos. 5,844,363, 6,303,238, and 5,707,745, which are incorporated herein by reference in their entirety. One type of device using phosphorescent molecules is a full-color display. The industry standard for such displays requires pixels suitable for emitting specific colors, also known as "standard" colors. Specifically, these standards require saturated red, green, and blue pixels. Colors can be measured using the CIE coordinate system, which is well-known in the technical field. An example of a green-emitting molecule is tris(2-phenylpyridine)iridium, named Ir(ppy)3, which has the following structure: [structure omitted]. In this text, and in the following diagrams, we depict the coordination bonds from nitrogen to the metal (here, Ir) as straight lines. The phrase "organic" as used herein includes polymeric materials as well as small-molecule organic materials suitable for manufacturing organic optoelectronic devices. "Small molecule" refers to any organic material that is not a polymer, and in practice, "small molecules" can be quite large. In some cases, small molecules may include repeating units. For example, using long-chain alkyl groups as substituents cannot remove the molecule from the "small molecule" category. Small molecules can also be included in the polymer, for example, as side groups on the polymer backbone or as part of the backbone. Small molecules can also be the core portion of a dendritic polymer composed of a series of chemical shells accumulated on the core portion. The core portion of the dendritic polymer can be a small molecule emitter that emits fluorescence or phosphorescence. Resin-like polymers can be "small molecules," and it is hereby considered that all dendritic polymers currently applicable to the OLED field are small molecules. The term "top" as used herein refers to the point furthest from the substrate, and "bottom" refers to the point closest to the substrate. When the first layer is described as "coated" on the second layer, the first layer is further away from the substrate. There may be other layers between the first and second layers unless it is specified that the first layer is "in contact" with the second layer. For example, even if there are multiple organic layers in between, the cathode can still be described as "coated" on the anode.The term "solution-handleable" as used herein refers to the ability to dissolve, disperse, or transport in a fluid medium (in solution or suspension) and / or to deposit from a fluid medium (in solution or suspension). A ligand is termed "photosensitive" when it is believed to directly promote the photosensitivity of a luminescent material. A ligand is termed "auxiliary" when it is believed not to promote the photosensitivity of a luminescent material, but auxiliary ligands may alter the properties of the photosensitizing ligand. As used herein and as generally understood by those skilled in the art, if the first energy level is closer to the vacuum level, then the first "highest occupied molecular orbital" (HOMO) or "lowest unoccupied molecular orbital" (LUMO) energy level is "greater than" or "higher than" the second HOMO or LUMO energy level. Since the ionization potential (IP) is measured as a negative energy relative to the vacuum level, a higher HOMO energy level corresponds to an IP with a smaller absolute value (a smaller negative IP). Similarly, a higher LUMO level corresponds to a smaller absolute value of electron affinity (EA) (a smaller negative EA). On a conventional energy level diagram, the vacuum level is at the top, and the LUMO level of a material is higher than the HOMO level of the same material. A "higher" HOMO or LUMO level appears closer to the top of the diagram than a "lower" HOMO or LUMO level. As used herein and as generally understood by those skilled in the art, if the first work function has a higher absolute value, then the first work function is "greater" or "higher" than the second work function. Since the work function is generally determined to be negative relative to the vacuum level, this point implies that the "higher" work function has a larger negative value. On a conventional energy level diagram, the vacuum level is at the top, and a "higher" work function is plotted as being further away from the vacuum level in the downward direction. Therefore, the definitions of HOMO and LUMO levels follow a different general method than those for work functions. Further details regarding OLEDs and the aforementioned definitions can be found in US Patent No. 7,279,704, which is incorporated herein by reference in its entirety. [Summary of the Invention] This invention provides compounds comprising metal complexes having novel ligand structures. These compounds are suitable for use in organic light-emitting devices. Specifically, these compounds can be used as phosphorescent dopants in such devices. These novel compounds comprise ligands having the following structure: Formula I. A is a 5- or 6-membered aromatic or heteroaromatic ring. In one state, preferably, A is benzene. In another state, preferably, A is selected from the group consisting of furans, thiophenes, and pyrroles. RA is a substituent having the following structure: , wherein the substituent is fused to the pyridine ring of Formula I. The dashed line appearing in the structure indicates the location where the substituent is fused to the pyridine ring of Formula I. X is selected from the group consisting of CRR', C=O, BR, O, S, and Se. R and R' are independently selected from hydrogen and alkyl groups. R1, R2, and R3 may represent mono, di, tri, or tetrasubstituted compounds; R1, R2, and R3 are each independently selected from the group consisting of hydrogen, alkyl, alkoxy, amino, alkenyl, alkynyl, aralkyl, aryl, and heteroaryl groups. The coordination system coordinates to a metal having an atomic weight greater than 40. Preferably, the metal is Ir. In one state, a compound comprising an aza-diphenyl substituted (aza-DBX) ligand having the following structure is provided: In another state, a compound wherein the ligands have the following structure is provided: However, in yet another state, a compound wherein the ligands have the following structure is provided: However, in yet another state, a compound wherein the ligands have the following structure is provided: However, in yet another state, a compound wherein the ligands have the following structure is provided: In a further state, a compound wherein the ligands have the following structure is provided: Preferably, the compound has the chemical formula (L)n(L')3-nIr. L is selected from the group consisting of: , , , , and . L' is selected from the group consisting of: , , , , , , , , . n is 1, 2, or 3. In one state, n is 1. In another state, n is 2. However, in yet another state, n is 3. R4 and R5 may represent mono, di, tri, or tetrasubstituted; and R4 and R5 are independently selected from the group consisting of hydrogen, alkyl, alkoxy, amino, alkenyl, alkynyl, aralkyl, aryl, and heteroaryl. Preferably, R4 and R5 are independently selected from hydrogen and alkyl. In one state, R1, R2, R3, R4, and R5 are each independently selected from hydrogen and alkyl. In another state, the compound is selected from the group consisting of: , ... In one specific embodiment, compounds comprising an azaDBX ligand and / or a phenylpyridine ligand are preferred. In another specific embodiment, compounds comprising an azaDBX and an auxiliary ligand (such as acetic acid) are preferred. The present invention provides specific examples of compounds comprising ligands having formula I, and includes compounds 1 to 24, 37 to 96, and 115 to 150.In one state, compounds comprising compounds 1 to 12 and / or compounds 61 to 78 wherein X is O (i.e., azidibenzofuran) are provided. In another state, compounds comprising compounds 13 to 24 and / or compounds 79 to 96 wherein X is S (i.e., azidibenzothiophene) are provided. However, in yet another state, compounds comprising compounds 37 to 48 and / or compounds 155 to 132 wherein X is CRR' (i.e., azirmonene) are provided. However, in yet another state, compounds comprising compounds 49 to 60 and / or compounds 133 to 150 wherein X is C=O (i.e., azirmonone) are provided. Furthermore, the present invention provides an organic light-emitting device. The device includes an anode, a cathode, and an organic layer located between the anode and the cathode. The organic layer further includes a compound comprising a ligand having the above-described chemical formula I. Specifically, the organic layer comprises a compound containing ligands having structures II, III, IV, V, VI, or VII as described above. Specifically, the organic layer comprises a compound selected from the group consisting of compounds 1 to 24, 37 to 96, and 115 to 150. Preferably, the organic layer is a light-emitting layer and the compound is a light-emitting dopant. The light-emitting layer may further comprise a host. Preferably, the host has the following chemical formula: R1', R2', R3', R4', R5', and R6' represent mono, di, tri, or tetrasubstituted compounds, and R1', R2', R3', R4', R5', and R6' are each independently selected from the group consisting of hydrogen, alkyl, and aryl groups. The selection of heteroatoms and substituents in compounds having chemical formula I is preferred and also preferred for devices including compounds having chemical formula I. These options include those described with respect to X, A, R1, R2, R3, R4, and R5. The present invention also provides a consumer product. The product includes a device having an anode, a cathode, and an organic layer located between the anode and the cathode. The organic layer further includes a compound comprising a ligand having the above-described structural formula I. The selection of heteroatoms and substituents preferred for compounds having formula I is also preferred for devices comprising compounds having formula I. These options include those described with respect to X, A, R1, R2, R3, R4, and R5.

Implementation Method

Claims

1. A compound comprising a ligand having the following structure, Wherein A is a 5- or 6-membered aromatic or heteroaromatic ring; where RA is a substituent having the following structure: where RA is fused to a pyridine ring of formula I; where X is selected from the group consisting of CRR', C=O, BR, O, S, and Se; where R and R' are independently selected from hydrogen and alkyl; where R1, R2, and R3 can represent mono, di, tri, or tetrasubstituted; where R1, R2, and R3 are each independently selected from the group consisting of hydrogen, alkyl, alkoxy, amino, alkenyl, alkynyl, aryl, and heteroaryl; where the coordination system is coordinated to Ir; and where the ligand has a structure selected from the group consisting of:

2. The compound of claim 1, wherein the compound has the chemical formula (L)n(L')3-nIr: wherein n is 1, 2, or 3; wherein L is selected from the group consisting of: The L' group is selected from the group consisting of: the X group is selected from the group consisting of CRR', C=O, BR, O, S, and Se; the R and R' groups are independently selected from hydrogen and alkyl; the A group is a 5- or 6-membered aromatic ring or heteroaromatic ring; the R4 and R5 groups can represent mono, di, tri, or tetrasubstituted groups; and the R4 and R5 groups are independently selected from the group consisting of hydrogen, alkyl, alkoxy, amino, alkenyl, alkynyl, aryl, and heteroaromatic groups.

3. The compound of claim 1, wherein the compound is selected from the group consisting of:

4. The use of a compound as a phosphorescent dopant in an OLED, wherein the compound is selected from the group consisting of: The X group is selected from the group consisting of CRR', C=O, BR, O, S and Se; the R and R' groups are independently selected from hydrogen and alkyl; R1, R2, R3, R4 and R5 can represent mono, di, tri, or tetrasubstituted; and each of R1, R2, R3, R4 and R5 is independently selected from the group consisting of hydrogen, alkyl, alkoxy, amino, alkenyl, alkynyl, aralkyl, aryl and heteroaryl.

5. The use of a compound as a phosphorescent dopant in an OLED, wherein the compound is selected from the group consisting of:

6. An organic light-emitting device, comprising: One anode; One cathode; and an organic layer located between the anode and the cathode, the organic layer further comprising a compound containing a ligand having the following structure: Wherein A is a 5- or 6-membered aromatic or heteroaromatic ring; where RA is a substituent having the following structure: where RA is fused to a pyridine ring of formula I; where X is selected from the group consisting of CRR', C=O, BR, O, S, and Se; where R and R' are independently selected from hydrogen and alkyl; where R1, R2, and R3 can represent mono, di, tri, or tetrasubstituted; where R1, R2, and R3 are each independently selected from the group consisting of hydrogen, alkyl, alkoxy, amino, alkenyl, alkynyl, aryl, and heteroaryl; where the coordination system is coordinated to a metal having an atomic weight greater than 40; and where the ligand has a structure selected from the group consisting of:

7. The apparatus of claim 6, wherein the compound is selected from the group consisting of:

8. The apparatus of claim 6, wherein the organic layer is a light-emitting layer and the compound is a light-emitting dopant.

9. The apparatus of claim 6, wherein the organic layer further comprises a body.

10. The apparatus of claim 9, wherein the main body has the following chemical formula: R'1, R'2, R'3, R'4, R'5, and R'6 can represent mono, di, tri, or tetrasubstituted; and each of R'1, R'2, R'3, R'4, R'5, and R'6 is independently selected from the group consisting of hydrogen, alkyl, and aryl groups.

11. A consumer product including a device, the device further comprising: One anode; one cathode; and an organic layer located between the anode and the cathode, the organic layer further comprising a compound as claimed in any one of claims 1 to 3.

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