Iridium complex with methyl-d3 substitution

Abstract

This invention provides novel organic compounds comprising deuterium-substituted ligands. Specifically, the compounds are iridium complexes comprising methyl-d3-substituted ligands. These compounds can be used in organic light-emitting devices to provide devices with improved color, efficiency, and lifespan.

Description

[Technical Field]

[0001] This invention relates to novel organic compounds suitable for use in organic light-emitting devices. More specifically, this invention relates to novel methyl-d3-substituted iridium complexes and their use in OLEDs.

[0002] This application claims priority to U.S. Provisional Application No. 61 / 173,346, filed on April 28, 2009, the disclosure of which is expressly incorporated herein by reference in its entirety.

[0003] The claimed invention arose from, or in the name of, one or more of, and / or jointly with, one or more of the following parties, under a joint university corporation research agreement: the University of Michigan, Princeton University, the University of Southern California, and the directors of Universal Display Corporation. This agreement was in effect on or prior to the date of the claimed invention, and the claimed invention arose from activities conducted within the scope of the agreement. [Previous Technology]

[0004] Optoelectronic devices utilizing organic materials are becoming increasingly necessary for many reasons. Because many of the materials used to manufacture these devices are relatively inexpensive, organic optoelectronic devices can potentially offer a cost advantage over inorganic devices. Furthermore, the inherent properties of organic materials, such as their flexibility, make them well-suited for specific applications, such as fabrication on flexible substrates. Examples of organic optoelectronic devices include organic light-emitting diodes (OLEDs), organic photoelectric crystals, organic photovoltaic cells, and organic photodetectors. For OLEDs, organic materials can offer performance advantages over conventional materials. For example, the wavelength of light emitted by an organic light-emitting layer can typically be easily adjusted using appropriate dopants.

[0005] OLEDs utilize organic thin films that emit light when a voltage is applied across the device. OLEDs are becoming an increasingly popular technology for applications such as flat panel displays, lighting, and backlighting. Several OLED materials and configurations are described in U.S. Patents 5,844,363, 6,303,238, and 5,707,745, which are incorporated herein by reference in their entirety.

[0006] One application of phosphorescent emitting molecules is in full-color displays. Industry standards for such displays require pixels that emit specific colors (called "saturated" colors). Specifically, these standards require saturated red, green, and blue pixels. Colors can be measured using the CIE coordinate system, which is well-known for this technology.

[0007] An example of a green light emitting molecule is tris(2-phenylpyridine)iridium, denoted as Ir(ppy)3, which has the following structure:

[0008]

[0009] In this figure and in subsequent figures, we depict the dative bond from nitrogen to the metal (Ir in this case) with straight lines.

[0010] As used herein, the term "organic" includes polymeric materials and small-molecule organic materials that can be used to manufacture organic optoelectronic devices. "Small molecule" refers to any organic material that is not a polymer, and a "small molecule" can actually be quite large. In some cases, a small molecule may include repeating units. For example, using long-chain alkyl groups as substituents does not exclude the molecule from the "small molecule" category. Small molecules may also be incorporated into the polymer, for example, as side groups on the polymer backbone or as part of the backbone. Small molecules may also serve as the core of a dendritic structure, which consists of a series of chemical shells built upon the core. The core of a dendritic structure may be a fluorescent or phosphorescent small-molecule emitter. Dendritic structures can be "small molecules," and it is believed that all dendritic structures currently used in the OLED field are small molecules.

[0011] As used herein, "top" means furthest from the substrate, and "bottom" means closest to the substrate. When the first layer is described as "placed above the second layer," the first layer is placed further away from the substrate. Unless specified that the first layer "contacts the second layer," other layers may exist between the first and second layers. For example, even if various organic layers exist between the cathode and the anode, the cathode may be described as "placed above the anode."

[0012] As used herein, "solution processable" means capable of dissolving, dispersing or transporting in and / or depositing from a liquid medium in the form of a solution or suspension.

[0013] When a photosensitive ligand directly promotes the photosensitivity of a luminescent material, the ligand can be called "photosensitive". When a photosensitive ligand does not promote the photosensitivity of a luminescent material, the ligand can be called "auxiliary", but auxiliary ligands may change the properties of photosensitizing ligands.

[0014] As used herein and as commonly understood by those skilled in the art, if the first "Highest Occupied Molecular Orbital" (HOMO) or "Lowest Unoccupied Molecular Orbital" (LUMO) level is closer to the vacuum level, then the first level is "greater than" or "higher than" the second HOMO or LUMO level. Because the ionization potential (IP) is measured to be negative relative to the vacuum level, a higher HOMO level corresponds to an IP with a smaller absolute value (IP is negative and has a smaller absolute value). Similarly, a higher LUMO level corresponds to an electron affinity (EA) with a smaller absolute value (EA is negative and has a smaller absolute value). On a conventional energy level diagram with the vacuum level at the top, the LUMO level of a material is higher than the HOMO level of the same material. A "higher" HOMO or LUMO level is closer to the top of the diagram than a "lower" HOMO or LUMO level.

[0015] As used herein and as commonly understood by those skilled in the art, if the first work function has a higher absolute value, then the first work function is "greater than" or "higher than" the second work function. Since the work function is typically measured to be negative relative to the vacuum level, this means that the "higher" work function is negative and has a larger absolute value. On a conventional energy level diagram with the vacuum level at the top, the "higher" work function is described as being farther from the vacuum level in the downward direction. Therefore, the definitions of the HOMO and LUMO energy levels follow different conventions than those for the work function.

[0016] Further details regarding OLEDs and the above definitions can be found in U.S. Patent No. 7,279,704, which is incorporated herein by reference in its entirety. [Summary of the Invention]

[0017] A compound comprising a ligand having the following structure:

[0018] . A and B may independently represent 5- or 6-membered aromatic or heteroaromatic rings. A is preferably selected from the group consisting of imidazole, pyrazole, triazole, oxazole, oxadiazole, pyridine, pyridazine, pyrimidine, pyrazine, and triazine. B is preferably selected from the group consisting of benzene, pyridine, furan, pyrrole, and thiophene. A1, A2, B1, and B2 are independently C or N. RA and RB may represent mono, di, or trisubstituted. XA and XB are independently C or heteroatoms. RA, RB, R1, and R2 are independently selected from the group consisting of hydrogen, alkyl, alkoxy, amino, alkenyl, alkynyl, aralkyl, aryl, and heteroaryl. At least one of RA, RB, R1, and R2 includes CD, CD2, or CD3. At least one of RA, RB, R1, and R2 preferably includes CD3. RA, RB, R1, and R2 may be bonded. RA, RB, R1, and R2 can fused. This coordination system coordinates with a metal having an atomic mass greater than 40. The preferred metal is Ir.

[0019] In one state sample, the ligand has the following structure:

[0020]

[0021] In one state, XA and XB are independently C or N, and when XA is N, R1 is aryl. In another state, XA and XB are independently C or N, and when XA is N, R1 is phenyl, further substituted by a group consisting of alkyl, alkoxy, amino, alkenyl, alkynyl, aralkyl, aryl, and heteroaryl groups, wherein such group includes at least one of CD, CD2, or CD3.

[0022] In one state, a class of compounds is provided, wherein at least one of the substituents RA and RB is a CD3 directly connected to ring A or ring B, or is bound to or fused to the ring A or ring B.

[0023] In detail, a compound comprising a ligand is provided, wherein the coordination system is selected from the group consisting of:

[0024]

[0025] R1, R2, R3, R4, R5, R6, R7, R8, R9 and R10 are independently selected from the group consisting of hydrogen, alkyl, alkoxy, amino, alkenyl, alkynyl, aryl, and heteroaryl. At least one of R1, R2, R3, R4, R5, R6, R7, R8, R9 and R10 is CD3.

[0026] In another state, the compound comprises ligands selected from formulas II, III, IV, V, VI, and VII. R1, R2, R3, R4, R5, R6, R7, R8, R9, and R10 are independently selected from the group consisting of hydrogen, alkyl, alkoxy, amino, alkenyl, alkynyl, aralkyl, aryl, and heteroaryl. At least one of R1, R2, R3, R4, R5, R6, R7, R8, R9, and R10 comprises CD3.

[0027] In another state, a compound comprising a ligand selected from the group consisting of:

[0028]

[0029] R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, and R11 are independently selected from the group consisting of hydrogen, alkyl, alkoxy, amino, alkenyl, alkynyl, aryl, and heteroaryl. R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, and R11 are bondable. R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, and R11 are fused. At least one of R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, and R11 includes an alkyl group comprising CD, CD2, or CD3.

[0030] Specific examples of iridium complexes substituted with methyl-deuterium (also referred to herein as methyl-d3 or CD3) are provided, and such examples include compounds selected from the group consisting of compounds 2-42. In one state, a class of compounds is provided, wherein the compounds contain ligands having formula II, such as compounds 2-4. In another state, a class of compounds is provided, wherein the compounds contain ligands having formula III, such as compounds 5-9. In another state, a class of compounds is provided, wherein the compounds contain ligands having formula IV, such as compounds 10-14 and 27-40. In another state, a class of compounds is provided, wherein the compounds contain ligands having formula V, such as compounds 15-19. In another state, a class of compounds is provided, wherein the compounds contain ligands having formula VI, such as compounds 20-23. In another state, a class of compounds is provided, wherein the compounds contain ligands having formula VII, such as compounds 24-26, 41 and 42.

[0031] Other specific examples of deuterium-substituted compounds include compounds selected from the group consisting of compounds 43-82. In one state sample, a class of compounds is provided, wherein the compounds contain ligands having formula III, such as compounds 58, 59, 68-70, and 75-77. In another state sample, a class of compounds is provided, wherein the compounds contain ligands having formula IV, such as compounds 43-52, 62-67, and 80-82. In another state sample, a class of compounds is provided, wherein the compounds contain ligands having formula V, such as compounds 55-57, 73, and 74. In another state sample, a class of compounds is provided, wherein the compounds contain ligands having formula VI, such as compounds 60, 61, 78, and 79. In another state sample, a class of compounds is provided, wherein the compounds contain ligands having formula VIII, such as compounds 53, 54, 71, and 72.

[0032] In one state, a homooleptic compound is provided. Specifically, a class of compounds is provided in which the ligand having Formula I is a ligand in a homooleptic compound. In another state, a heterooleptic compound is provided. Specifically, a class of compounds is provided in which the ligand having Formula I is a ligand in a heterooleptic compound.

[0033] An organic light-emitting device is also provided. The device may include an anode, a cathode, and an organic light-emitting layer disposed between the anode and the cathode. The organic layer further includes a ligand having the structure of Formula I as described above.

[0034] A and B can independently represent 5- or 6-membered aromatic or heteroaromatic rings. A1, A2, B1, and B2 are independently C or N. RA and RB can represent mono, di, or trisubstituted. XA and XB are independently C or heteroatoms. RA, RB, R1, and R2 are independently selected from the group consisting of hydrogen, alkyl, alkoxy, amino, alkenyl, alkynyl, aralkyl, aryl, and heteroaryl. At least one of RA, RB, R1, and R2 includes CD, CD2, or CD3. At least one of RA, RB, R1, and R2 preferably includes CD3. RA, RB, R1, and R2 can be bonded. RA, RB, R1, and R2 can be fused. This coordination system coordinates with a metal having an atomic weight greater than 40.

[0035] In one state, XA and XB are independently C or N, and when XA is N, R1 is aryl. In another state, XA and XB are independently C or N, and when XA is N, R1 is phenyl, further substituted by a group consisting of alkyl, alkoxy, amino, alkenyl, alkynyl, aralkyl, aryl, and heteroaryl groups, wherein such group includes at least one of CD, CD2, or CD3.

[0036] The preferred selection of aromatic rings, metals, and substituents for compounds comprising ligands having formula I is also preferred for devices comprising compounds comprising ligands having formula I. These selections include metal M, rings A and B, and substituents RA, RB, A1, A2, B1, B2, R1, and R2.

[0037] At least one of the substituents RA and RB is preferably CD3 directly connected to ring A or ring B, or combined or fused to the ring A or ring B.

[0038] Ir is the preferred metal.

[0039] A is preferably selected from the group consisting of imidazole, pyrazole, triazole, oxazole, oxadiazole, pyridine, pyridazine, pyrimidine, pyrazine and triazine. B is preferably selected from the group consisting of benzene, pyridine, furan, pyrrole and thiophene.

[0040] Specifically, the organic layer of the device may comprise compounds having ligands selected from the group consisting of formulas II-VII, wherein R1, R2, R3, R4, R5, R6, R7, R8, R9, and R10 are independently selected from the group consisting of hydrogen, alkyl, alkoxy, amino, alkenyl, alkynyl, aralkyl, aryl, and heteroaryl. At least one of R1, R2, R3, R4, R5, R6, R7, R8, R9, and R10 is CD3. The organic layer preferably comprises compounds selected from the group consisting of compounds 2-42.

[0041] Additionally, the organic layer of the device may contain compounds having ligands selected from the group consisting of formulas II-VII, wherein R1, R2, R3, R4, R5, R6, R7, R8, R9 and R10 are independently selected from the group consisting of hydrogen, alkyl, alkoxy, amino, alkenyl, alkynyl, aralkyl, aryl and heteroaryl. At least one of R1, R2, R3, R4, R5, R6, R7, R8, R9 and R10 is CD3.

[0042] Furthermore, the organic layer of the device may comprise a compound having a ligand selected from the group consisting of formulas III-VIII. R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, and R11 are independently selected from the group consisting of hydrogen, alkyl, alkoxy, amino, alkenyl, alkynyl, aralkyl, aryl, and heteroaryl. R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, and R11 may be bonded. R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, and R11 may be fused. At least one of R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, and R11 includes an alkyl group comprising CD, CD2, or CD3. The organic layer preferably contains compounds selected from the group consisting of compounds 43-82.

[0043] In one state, the organic layer is a luminescent layer containing a compound provided herein, wherein the compound is a luminescent dopant. The organic layer may additionally include a host. The host preferably has the following formula: R'1, R'2, R'3, R'4, R'5, and R'6 may represent mono, di, tri, or tetrasubstituted; and R'1, R'2, R'3, R'4, R'5, and R'6 are each independently selected from the group consisting of hydrogen, alkyl, and aryl. The host is more preferably H1.

[0044] A consumer product incorporating the device is also provided. The device includes an anode, a cathode, and an organic layer disposed between the anode and the cathode. The organic layer includes a compound containing a ligand having the structure of Formula I as described above.

[0045] A and B can independently represent 5- or 6-membered aromatic or heteroaromatic rings. A1, A2, B1, and B2 are independently C or N. RA and RB can represent mono, di, or trisubstituted. XA and XB are independently C or heteroatoms. RA, RB, R1, and R2 are independently selected from the group consisting of hydrogen, alkyl, alkoxy, amino, alkenyl, alkynyl, aralkyl, aryl, and heteroaryl. At least one of RA, RB, R1, and R2 includes CD, CD2, or CD3. At least one of RA, RB, R1, and R2 preferably includes CD3. RA, RB, R1, and R2 can be bonded. RA, RB, R1, and R2 can be fused. This coordination system coordinates with a metal having an atomic weight greater than 40.

[0046] The preferred selection of aromatic rings, metals, and substituents of compounds comprising ligands having Formula I is also preferred for consumer products comprising devices comprising compounds comprising ligands having Formula I. These selections include metal M, rings A and B, and substituents RA, RB, A1, A2, B1, B2, R1, and R2. [Simplified Explanation of the Diagram]

[0192] Figure 1 shows an organic light-emitting device.

[0193] Figure 2 shows an inverted organic light-emitting device without an independent electron transport layer.

[0194] Figure 3 shows the general structure of a ligand containing deuterium substitution.

[0195] Figure 4 shows an exemplary ligand substituted with methyl-d3.

Implementation Method

[0047] Typically, an OLED comprises at least one organic layer disposed between and electrically connected to both an anode and a cathode. When a current is applied, the anode injects holes into the organic layer, and the cathode injects electrons into the organic layer. The injected holes and electrons migrate toward the electrodes with opposite charges. When electrons and holes are localized on the same molecule, an "exciton" is formed, which is a localized electron-hole pair with an excited energy state. Light is emitted when the exciton relaxes via a photoemission mechanism. In some cases, excitons may be localized on excimers or excited complexes. Non-radiative mechanisms such as thermal relaxation may also occur, but are generally considered undesirable.

[0048] As disclosed, for example, in U.S. Patent No. 4,769,292 (incorporated in its entirety), OLEDs initially used light-emitting molecules that emitted light from a singlet state (“fluorescence”). Fluorescence emission typically occurs within a time frame of less than 10 nanoseconds.

[0049] Recently, OLEDs with self-triple-state emission (“phosphorescence”) luminescent materials have been demonstrated. References include Baldo et al., “Highly Efficient Phosphorescent Emission from Organic Electroluminescent Devices,” Nature, Vol. 395, 151-154, 1998; (“Baldo-I”) and Baldo et al., “Very high-efficiency green organic light-emitting devices based on electrophosphorescence,” Appl. Phys. Lett., Vol. 75, No. 3, 4-6 (1999) (“Baldo-II”), which are incorporated herein by reference in their entirety. Phosphorescence is described in more detail in columns 5-6 of U.S. Patent No. 7,279,704 (incorporated by reference).

[0050] Figure 1 shows an organic light-emitting device 100. These figures are not necessarily drawn to scale. Device 100 may include a substrate 110, an anode 115, a hole injection layer 120, a hole transport layer 125, an electron blocking layer 130, a light-emitting layer 135, a hole blocking layer 140, an electron transport layer 145, an electron injection layer 150, a protective layer 155, and a cathode 160. The cathode 160 is a compound cathode having a first conductive layer 162 and a second conductive layer 164. Device 100 may be manufactured by sequentially depositing the aforementioned layers. The properties and functions of these different layers, as well as example materials, are described in more detail in columns 6-10 of US 7,279,704 (incorporated by reference).

[0051] Further examples of such layers are available. For example, U.S. Patent No. 5,844,363 (incorporated in its entirety) discloses a flexible and transparent substrate-anode combination. As disclosed in U.S. Patent Application Publication No. 2003 / 0230980 (incorporated in its entirety), an example of a p-doped hole transport layer is m-MTDATA with F4-TCNQ doped at a 50:1 molar ratio. Examples of luminescent and host materials are disclosed in U.S. Patent No. 6,303,238 to Thompson et al. (incorporated in its entirety). As disclosed in U.S. Patent Application Publication No. 2003 / 0230980 (incorporated in its entirety), an example of an n-doped electron transport layer is BPhen with Li doped at a 1:1 molar ratio. U.S. Patent Nos. 5,703,436 and 5,707,745 (incorporated in their entirety) disclose examples of cathodes, including composite cathodes having a thin layer of metal (such as Mg:Ag) overlaid with a transparent, conductive, sputtered ITO layer. U.S. Patent No. 6,097,147 and U.S. Patent Application Publication No. 2003 / 0230980 (incorporated in their entirety) describe the theory and use of barrier layers in more detail. Examples of implantation layers are provided in U.S. Patent Application Publication No. 2004 / 0174116 (incorporated in their entirety). A description of protective layers can be found in U.S. Patent Application Publication No. 2004 / 0174116, which is incorporated in its entirety.

[0052] Figure 2 shows an inverted OLED 200. The device includes a substrate 210, a cathode 215, a light-emitting layer 220, a hole transport layer 225, and an anode 230. The device 200 can be manufactured by sequentially depositing the layers. Because in the most common OLED configuration the cathode is positioned above the anode, while in device 200 the cathode 215 is positioned below the anode 230, the device 200 can be called an "inverted" OLED. Materials similar to those described for device 100 can be used in the corresponding layers of device 200. Figure 2 provides an example of how some layers can be omitted from the structure of device 100.

[0053] The simple layered structures illustrated in Figures 1 and 2 are provided as non-limiting examples, and it should be understood that embodiments of the invention can be used in combination with a variety of other structures. The specific materials and structures described are illustrative in nature, and other materials and structures can be used. Functional OLEDs can be obtained by combining the various layers in different ways, or the layers can be omitted entirely depending on design, performance, and cost factors. Other layers not specifically described may also be included. Materials other than those specifically described may be used. Although many examples provided herein describe various layers as comprising a single material, it should be understood that combinations of materials, such as mixtures of a host and dopant, or more generally mixtures, may also be used. These layers may also have various sublayers. The names given to the various layers herein are not intended to be strictly limiting. For example, in device 200, hole transport layer 225 transports and injects holes into light-emitting layer 220, and may be described as a hole transport layer or a hole injection layer. In one embodiment, an OLED may be described as having an "organic layer" disposed between a cathode and an anode. For example, in Figures 1 and 2, this organic layer may comprise a single layer or additionally comprise multiple layers of different organic materials.

[0054] As disclosed in U.S. Patent No. 5,247,190 to Friend et al. (incorporated in its entirety by reference), structures and materials not specifically described may also be used, such as OLEDs (PLEDs) comprising polymeric materials. Alternatively, an OLED having a single organic layer may be used. For example, as described in U.S. Patent No. 5,707,745 to Forrest et al. (incorporated in its entirety by reference), OLEDs may be stacked. The OLED structure may deviate from the simple layered structure illustrated in Figures 1 and 2. For example, the substrate may include angled reflective surfaces to improve external coupling, such as the mesa structure described in U.S. Patent No. 6,091,195 to Forrest et al., and / or the pit structure described in U.S. Patent No. 5,834,893 to Bulovic et al., all of which are incorporated herein by reference in their entirety.

[0055] Unless otherwise specified, any layer of the various embodiments may be deposited by any suitable method. For organic layers, preferred methods include thermal evaporation and inkjet printing as described in U.S. Patent Nos. 6,013,982 and 6,087,196 (incorporated in their entirety); organic vapor phase deposition (OVPD) as described in U.S. Patent No. 6,337,102 to Forrest et al. (incorporated in their entirety); and deposition by organic vapor jet printing (OVJP) as described in U.S. Patent Application No. 10 / 233,470 (incorporated in their entirety). Other suitable deposition methods include spin coating and other solution-based methods. Solution-based methods are preferably performed in a nitrogen or inert atmosphere. For other layers, preferred methods include thermal evaporation. Preferred patterning methods include patterning via mask deposition, cold bonding (as described in U.S. Patents 6,294,398 and 6,468,819, which are incorporated herein by reference in their entirety), and patterning in conjunction with some deposition methods such as inkjet and OVJD. Other methods may also be used. The material to be deposited may be modified to make it compatible with a particular deposition method. For example, branched or unbranched substituents (such as alkyl and aryl groups) containing at least three carbons may be used in small molecules to enhance their solution processability. Substituents having 20 or more carbons may be used, with 3-20 carbons being a preferred range. Because asymmetric materials may have a lower tendency to recrystallize, materials with asymmetric structures may have better solution processability than materials with symmetric structures. Dendritic substituents may be used to enhance the solution processability of small molecules.

[0056] Devices manufactured according to embodiments of the present invention can be incorporated into a variety of consumer products, including flat panel displays, computer monitors, televisions, billboards, lights for indoor or outdoor lighting and / or signaling, head-up displays, full-view displays, flexible displays, laser printers, telephones, mobile phones, personal digital assistants (PDAs), laptops, digital cameras, video cameras, viewfinders, microdisplays, vehicles, large-area walls, theater or stadium screens or signs. Various control mechanisms can be used to control devices manufactured according to the present invention, including passive and active matrices. Many devices are intended for use within a temperature range of human comfort, such as 18°C ​​to 30°C, and more preferably at room temperature (20-25°C).

[0057] The materials and structures described herein can be applied to devices other than OLEDs. For example, other optoelectronic devices such as organic solar cells and organic photodetectors can use these materials and structures. More generally, organic devices such as organic transistors can use these materials and structures.

[0058] The terms halogen, halogen, alkyl, cycloalkyl, alkenyl, alkynyl, aralkyl, heterocyclic, aryl, aromatic and heteroaryl are known in the art and are defined in columns 31-32 of US 7,279,704 (incorporated herein by reference).

[0059] As used herein, the terms alkyl, aryl, and heteroaryl also include deuterium in place of hydrogen. For example, alkyl may include CH3 or CD3 and CH2CH3 or CH2CD3. Similarly, aryl and heteroaryl may include aromatic groups substituted with deuterium rather than hydrogen.

[0060] Substitution of hydrogen in iridium complexes with the hydrogen isotope deuterium has been reported in the literature (see, for example, U.S. Publication No. 2008 / 0194853 and U.S. Patent No. 6,699,599). It is noteworthy that direct substitution of deuterium atoms on the ring does not appear to provide color adjustment. Specifically, the inventors are unaware of any reports of changes in the luminescence profile of compounds substituted with deuterium atoms.

[0061] CD3 substitution in the host material has also been reported (see WO 2008029670). However, the luminescence profile of the luminescent dopant is an important property of the compound, and substitution of the host material does not provide any information about color adjustment. Specifically, when the modified compounds presented herein are host materials rather than luminescent materials, the effect of deuterium substitution on the photoluminescence spectrum (e.g., color adjustment properties) cannot be evaluated. Therefore, luminescent compounds with the beneficial properties of methyl substitution (i.e., color adjustment, improved quantum efficiency, and improved lifetime) and deuterium-related improved stability may be required.

[0062] Methyl substitution in metal complexes has been shown to be useful for adjusting the photophysical and electroluminescent properties of compounds. For example, methyl substitution at certain positions can be beneficial for improving quantum efficiency, linearity, and OLED lifetime.

[0063] This document provides novel compounds comprising ligands having a methyl-d3 substituent (illustrated in Figure 3). Furthermore, specific ligands containing a methyl-d3 substituent are also provided (illustrated in Figure 4). Notably, the disclosed compounds can provide improved photoluminescence and improved device efficiency.

[0064] The compounds provided herein contain ligands with methyl-d3 substitution. These compounds are suitable for use in OLEDs to improve device efficiency, lifespan, and color (e.g., color adjustment). Without being theoretically constrained, it is believed that CD3 substitution results in strong CD bonds, which can improve stability. As discussed above, the strength of CD bonds is greater than that of CH bonds. Furthermore, the smaller van der Waals radius of deuterium can be understood as smaller spatial substituents (e.g., less twisting on aromatic rings containing CD3 substituents rather than CH3 substituents in the ortho position), and thus improved conjugation in systems with CD3 substitution. Moreover, due to the kinetic isotope effect, the reaction rate of chemical processes involving CD bonds present in methyl-d3 may be slower. If the chemical degradation of the luminescent compound involves the breaking of methyl-CH bonds, stronger CD bonds can improve the stability of the compound.

[0065] Methyl groups are the simplest alkyl substitutions added to compounds as modifications. They are extremely important substituents for modifying the properties of the host and emitter in OLEDs. Methyl groups can affect solid-state filling properties (i.e., sublimation and charge transport properties), modify photophysical properties, and affect device stability. Methyl groups have been introduced to alter the properties of the tris(2-phenylpyridine)iridium(III) family. For example, devices using tris(3-methyl-2-phenylpyridine)iridium(III) as the emitter have better stability than devices using tris(2-phenylpyridine)iridium(III) as the emitter. Furthermore, the emission peak of tris(3-methyl-2-phenylpyridine)iridium(III) is red-shifted by about 10 nm. The evaporation temperature of tris(3-methyl-2-phenylpyridine)iridium(III) is also about 20 degrees lower than that of tris(2-phenylpyridine)iridium(III).

[0066] On the other hand, the methyl group is also considered reactive due to the proton in the benzyl group. Without theoretical constraints, the hydrogen atoms present in the methyl group may be particularly reactive and therefore could be chemical degradation sites in the luminescent compound. Furthermore, it is generally accepted in the field that doped compounds are oxidized during OLED operation. In the oxidized state, the benzyl position may become the weakest position, leading to further chemical degradation. When using luminescent dopants, the proposed mechanism may be more related to certain hosts (such as terphenyl / DBT hybrid materials) and less related to other hosts (such as Balq). Therefore, the substitution of hydrogen atoms in the methyl group with deuterium atoms (methyl-d3) can stabilize the luminescent compound.

[0067] Because the mass of a deuterium atom is twice that of a hydrogen atom, it produces a lower zero-point energy and a lower vibrational energy level. Therefore, it is believed that deuterium substitution can improve efficiency and stability. Furthermore, the bond lengths and bond angles involved in deuterium differ from those involved in hydrogen. Specifically, since the CD bond extends less than the CH bond, the van der Waals radius of deuterium is smaller than that of hydrogen. CD bonds are generally shorter and stronger than CH bonds. Therefore, CD3 substitution can provide the same color adjustment and all the advantages associated with increased bond strength (i.e., improved efficiency and lifetime).

[0068] As discussed above, deuteration provides many benefits, such as increased efficiency and lifetime. Therefore, compounds containing deuterated ligands are suitable for use in organic light-emitting devices. Such compounds include, for example, compounds containing ligands with deuterium located within the alkyl chain (e.g., C(D)(H)CH3, CD2CH3, and CH2CD2CH3) and deuterium located at the end of the alkyl chain (e.g., CD3).

[0069] This document provides novel compounds comprising ligands having the following structures:

[0070] . A and B may independently represent 5- or 6-membered aromatic or heteroaromatic rings. A is preferably selected from the group consisting of imidazole, pyrazole, triazole, oxazole, oxadiazole, pyridine, pyridazine, pyrimidine, pyrazine, and triazine. B is preferably selected from the group consisting of benzene, pyridine, furan, pyrrole, and thiophene. A1, A2, B1, and B2 are independently C or N. RA and RB may represent mono, di, or trisubstituted. XA and XB are independently C or heteroatoms. RA, RB, R1, and R2 are independently selected from the group consisting of hydrogen, alkyl, alkoxy, amino, alkenyl, alkynyl, aryl, and heteroaryl. At least one of RA, RB, R1, and R2 includes CD, CD2, or CD3. At least one of RA, RB, R1, and R2 preferably includes CD3. RA, RB, R1, and R2 may be bonded. RA, RB, R1, and R2 can fused. This coordination system coordinates with a metal having an atomic mass greater than 40. The preferred metal is Ir.

[0071] In one state sample, the ligand has the following structure:

[0072]

[0073] In one state, XA and XB are independently C or N, and when XA is N, R1 is aryl. In another state, XA and XB are independently C or N, and when XA is N, R1 is phenyl, further substituted by a group consisting of alkyl, alkoxy, amino, alkenyl, alkynyl, aralkyl, aryl, and heteroaryl groups, wherein such group includes at least one of CD, CD2, or CD3.

[0074] In one state, a class of compounds is provided, wherein at least one of the substituents RA and RB is a CD3 directly connected to ring A or ring B, or is bound to or fused to the ring A or ring B.

[0075] As discussed above, substituents RA and RB can be fused to ring A and / or ring B. Substituents RA and RB can be any substituents, including substituents that are bonded, fused to ring A and / or ring B, or not fused to ring A and / or ring B.

[0076] In detail, a compound comprising a ligand is provided, wherein the coordination system is selected from the group consisting of:

[0077]

[0078] R1, R2, R3, R4, R5, R6, R7, R8, R9 and R10 are independently selected from the group consisting of hydrogen, alkyl, alkoxy, amino, alkenyl, alkynyl, aryl and heteroaryl; and at least one of R1, R2, R3, R4, R5, R6, R7, R8, R9 and R10 is CD3.

[0079] Furthermore, a compound comprising a ligand is provided, wherein the coordination system is selected from the group consisting of:

[0080]

[0081] R1, R2, R3, R4, R5, R6, R7, R8, R9 and R10 are independently selected from the group consisting of hydrogen, alkyl, alkoxy, amino, alkenyl, alkynyl, aryl and heteroaryl; and at least one of R1, R2, R3, R4, R5, R6, R7, R8, R9 and R10 includes CD3.

[0082] The compound contains ligands selected from the group consisting of:

[0083]

[0084]

[0085] R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, and R11 are independently selected from the group consisting of hydrogen, alkyl, alkoxy, amino, alkenyl, alkynyl, aryl, and heteroaryl; and R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, and R11 are bondable. R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, and R11 are fused. At least one of R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, and R11 includes an alkyl group comprising CD, CD2, or CD3.

[0086] Specific examples of iridium complexes substituted with methyl-d3 are provided, including compounds selected from the group consisting of:

[0087]

[0088]

[0089]

[0090]

[0091] Other specific examples of deuterated iridium complexes are provided, including compounds selected from the group consisting of:

[0092]

[0093]

[0094]

[0095]

[0096]

[0097] In one state sample, a class of compounds is provided, wherein the compounds contain ligands having formula II, such as compounds 2-4.

[0098] In another state, a class of compounds is provided, wherein the compounds contain ligands having formula III, such as compounds 5-9.

[0099] In another state, other compounds comprising ligands having formula III are provided, including compounds 58, 59, 68-70 and 75-77.

[0100] In another state, a class of compounds is provided, wherein the compounds contain ligands having formula IV, such as compounds 10-14 and 27-40.

[0101] In another state, other compounds comprising ligands having formula IV are provided, including compounds 43-52, 62-67 and 80-82.

[0102] In another state, a class of compounds is provided, wherein the compounds contain ligands having formula V, such as compounds 15-19.

[0103] In another state, other compounds comprising ligands having formula V are provided, including compounds 55-57, 73 and 74.

[0104] In another state, a class of compounds is provided, wherein the compounds contain ligands having formula VI, such as compounds 20-23.

[0105] In another state, other compounds comprising ligands having formula VI are provided, including compounds 60, 61, 78 and 79.

[0106] In another state, a class of compounds is provided, wherein the compounds contain ligands having formula VII, such as compounds 24-26, 41 and 42.

[0107] In another embodiment, compounds comprising ligands having formula III are provided, including compounds 53, 54, 71 and 72.

[0108] Compounds containing ligands selected from formulas II, III, IV, V, VI and VII may be particularly stable doped compounds.

[0109] In addition, compounds containing ligands having formula VIII can also be particularly stable compounds.

[0110] In one state, a homopolymer compound containing CD3 is provided. Specifically, a class of compounds is provided in which the ligand having Formula I is a ligand in the homopolymer compound. The homopolymer compounds provided herein include, for example, compounds 2-19. In another state, a heteropolymer compound containing CD3 is provided. Specifically, a class of compounds is provided in which the ligand having Formula I is a ligand in the heteropolymer compound. The heteropolymer compounds provided herein include, for example, compounds 20-42. The heteropolymer compound containing CD3 may include compounds having luminescent and non-luminescent ligands, such as compounds 20-26 containing two luminescent ligands and one acetone ligand. Furthermore, the heteropolymer compound containing CD3 may include compounds in which all ligands are luminescent ligands and such luminescent ligands have different structures. In one state, the heteropolymer compound containing CD3 may have two luminescent ligands including CD3 and one luminescent ligand without CD3. For example, compounds 27, 33, and 35-40. In another state, the CD3-containing heteroligand may have one luminescent ligand including CD3 and two luminescent ligands not containing CD3. For example, compounds 29-32, 41, and 42. The CD3-containing luminescent ligand may include a single CD3 group (e.g., compounds 29-32), or the ligand may include several CD3 groups (e.g., compounds 41 and 42 contain a luminescent ligand with two CD3 substituents). In another state, the CD3-containing heteroligand may contain two or more different types of luminescent ligands, wherein all ligands contain CD3. For example, compounds 28 and 34.

[0111] Additionally, an organic light-emitting device is provided. The device includes an anode, a cathode, and an organic light-emitting layer disposed between the anode and the cathode. The organic layer contains a compound containing a ligand, the ligand having the following structure:

[0112] , as described above. The preferred selection of aromatic rings, metals, and substituents for compounds comprising ligands having formula I is also preferred for devices comprising compounds comprising ligands having formula I. These selections include metal M, rings A and B, and substituents RA, RB, A1, A2, B1, B2, R1, and R2.

[0113] A and B can independently represent 5- or 6-membered aromatic or heteroaromatic rings. A is preferably selected from the group consisting of imidazole, pyrazole, triazole, oxazole, oxadiazole, pyridine, pyridazine, pyrimidine, pyrazine, and triazine. B is preferably selected from the group consisting of benzene, pyridine, furan, pyrrole, and thiophene. A1, A2, B1, and B2 are independently C or N. RA and RB can represent mono, di, or trisubstituted. XA and XB are independently C or heteroatoms. RA, RB, R1, and R2 are independently selected from the group consisting of hydrogen, alkyl, alkoxy, amino, alkenyl, alkynyl, aryl, and heteroaryl. At least one of RA, RB, R1, and R2 includes CD, CD2, or CD3. At least one of RA, RB, R1, and R2 preferably includes CD3. RA, RB, R1, and R2 can be bonded. RA, RB, R1, and R2 can fused. This coordination system coordinates with a metal having an atomic mass greater than 40. The preferred metal is Ir.

[0114] In one state sample, the ligand has the following structure:

[0115]

[0116] In one state, XA and XB are independently C or N, and when XA is N, R1 is aryl. In another state, XA and XB are independently C or N, and when XA is N, R1 is phenyl, further substituted by a group consisting of alkyl, alkoxy, amino, alkenyl, alkynyl, aralkyl, aryl, and heteroaryl groups, wherein such group includes at least one of CD, CD2, or CD3.

[0117] In one state, a class of compounds is provided, wherein at least one of the substituents RA and RB is a CD3 directly connected to ring A or ring B, or is bound to or fused to the ring A or ring B.

[0118] As discussed above, substituents RA and RB can be fused to ring A and / or ring B. Substituents RA and RB can be any substituents, including substituents that are bonded, fused to ring A and / or ring B, or not fused to ring A and / or ring B.

[0119] Specifically, the organic layer of the device comprises compounds having ligands selected from the group consisting of formulas II-VII. R1, R2, R3, R4, R5, R6, R7, R8, R9, and R10 are independently selected from the group consisting of hydrogen, alkyl, alkoxy, amino, alkenyl, alkynyl, aralkyl, aryl, and heteroaryl. At least one of R1, R2, R3, R4, R5, R6, R7, R8, R9, and R10 is CD3. The organic layer preferably comprises compounds selected from the group consisting of compounds 2-42.

[0120] Additionally, the organic layer of the device comprises a compound having ligands selected from the group consisting of formulas II-VII. R1, R2, R3, R4, R5, R6, R7, R8, R9, and R10 are independently selected from the group consisting of hydrogen, alkyl, alkoxy, amino, alkenyl, alkynyl, aralkyl, aryl, and heteroaryl. At least one of R1, R2, R3, R4, R5, R6, R7, R8, R9, and R10 includes CD3.

[0121] Furthermore, the organic layer of the device may comprise a compound with ligands selected from the group consisting of formulas III-VIII. R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, and R11 are independently selected from the group consisting of hydrogen, alkyl, alkoxy, amino, alkenyl, alkynyl, aralkyl, aryl, and heteroaryl. R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, and R11 may be bonded. R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, and R11 may be fused. At least one of R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, and R11 comprises an alkyl group containing CD, CD2, or CD3. The organic layer preferably contains compounds selected from the group consisting of compounds 43-82.

[0122] In one embodiment, the organic layer is a light-emitting layer containing a compound having a ligand of Formula I, wherein the compound is a light-emitting dopant. The organic layer may further comprise a host. The host preferably has the following formula:

[0123] . R'1, R'2, R'3, R'4, R'5 and R'6 may represent mono, di, tri, or tetrasubstituted; and R'1, R'2, R'3, R'4, R'5 and R'6 are each independently selected from the group consisting of hydrogen, alkyl and aryl. The host is preferably H1.

[0124] A consumer product incorporating the device is also provided. The device includes an anode, a cathode, and an organic layer disposed between the anode and the cathode. The organic layer includes a compound containing a ligand having the following structure: as described above. Preferred selections of aromatic rings, metals, and substituents for compounds containing ligands of Formula I are also preferred for devices including compounds containing ligands of Formula I. These selections include metal M, rings A and B, and substituents RA, RB, A1, A2, B1, B2, R1, and R2.

[0125] A and B can independently represent 5- or 6-membered aromatic or heteroaromatic rings. A is preferably selected from the group consisting of imidazole, pyrazole, triazole, oxazole, oxadiazole, pyridine, pyridazine, pyrimidine, pyrazine, and triazine. B is preferably selected from the group consisting of benzene, pyridine, furan, pyrrole, and thiophene. A1, A2, B1, and B2 are independently C or N. RA and RB can represent mono, di, or trisubstituted. XA and XB are independently C or heteroatoms. RA, RB, R1, and R2 are independently selected from the group consisting of hydrogen, alkyl, alkoxy, amino, alkenyl, alkynyl, aryl, and heteroaryl. At least one of RA, RB, R1, and R2 includes CD, CD2, or CD3. At least one of RA, RB, R1, and R2 preferably includes CD3. RA, RB, R1, and R2 can be bonded. RA, RB, R1, and R2 can fused. This coordination system coordinates with a metal having an atomic mass greater than 40. The preferred metal is Ir.

[0126] In one state, XA and XB are independently C or N, and when XA is N, R1 is aryl. In another state, XA and XB are independently C or N, and when XA is N, R1 is phenyl, further substituted by a group consisting of alkyl, alkoxy, amino, alkenyl, alkynyl, aralkyl, aryl, and heteroaryl groups, wherein such group includes at least one of CD, CD2, or CD3.

[0127] The consumer product may include an additional device comprising an organic layer containing a compound comprising a ligand having a structure selected from the group consisting of formulas II-VII. Specifically, the compound may be selected from the group consisting of compounds 2-42.

[0128] Furthermore, the organic layer of the device may contain compounds having ligands selected from the group consisting of formulas III-VIII. The organic layer preferably contains compounds selected from the group consisting of compounds 43-82.

[0129] In one embodiment, a particular consumer product comprising the device is provided. The device preferably contains a compound wherein at least one of the substituents RA and RB is a CD3 directly connected to ring A or ring B, or is bound to or fused to a ring A or ring B.

[0130] As discussed above, substituents RA and RB can be fused to ring A and / or ring B. Substituents RA and RB can be any substituents, including substituents that are bonded, fused to ring A and / or ring B, or not fused to ring A and / or ring B.

[0131] The materials described herein for use in specific layers of an organic light-emitting device can be combined with a variety of other materials present in the device. For example, the light-emitting dopants disclosed herein can be combined with various host layers, transport layers, blocking layers, injection layers, electrodes, and other possible layers. The materials described or mentioned below are non-limiting examples of materials that can be combined with the compounds disclosed herein, and those skilled in the art can easily consult the literature to identify other materials that can be combined.

[0132] In addition to and / or in combination with the materials disclosed herein, many hole injection materials, hole transport materials, host materials, doped materials, exciton / hole blocking layer materials, electron transport and electron injection materials can be used in OLEDs. Non-limiting examples of materials that can be used in OLEDs in combination with the materials disclosed herein are listed in Table 1 below. Table 1 lists the non-limiting types of materials, non-limiting examples of various compounds, and references disclosing such materials.

[0133]

[0134]

[0135]

[0136]

[0137]

[0138]

[0139]

[0140]

[0141]

[0142]

[0143]

[0144] Experiment

[0145] Examples of Compounds

[0146] Example 1. Synthesis of compound 10

[0147]

[0148] Synthesis of 2-bromo-6-phenylpyridine. In a 1L round-bottom flask with a condenser, nitrogen inlet, and two stoppers, 228 mL of dimethoxyethane containing 2,6-dibromopyridine (15.3 g, 64.58 mmol), phenyl acid (7.87 g, 64.58 mmol), and potassium carbonate (17.85 g, 129.16 mmol) and 150 mL of water were added. Nitrogen was bubbled directly into the mixture for 15 minutes. Tetra(triphenylphosphine)palladium(O) (1.85 g, 1.60 mmol) was added, and the reaction mixture was heated to reflux. After heating for 3 hours, the reaction was complete. The mixture was cooled to room temperature and diluted with water and ethyl acetate. The layers were separated, and the aqueous layer was extracted with ethyl acetate. The organic layer was dried over magnesium sulfate, filtered, and evaporated. The product was purified by column chromatography by dissolution in 2% ethyl acetate / hexane, followed by vacuum distillation using Kugelrohr at 150 °C. 5.2g of product (34%) was obtained.

[0149]

[0150] Synthesis of 2-phenyl-6-methyl-d3-pyridine. A 500 mL round-bottom flask with a dropping funnel, nitrogen inlet, and stopper was dried under vacuum using an air heat gun. 11.3 g (48.27 mmol) of 2-bromo-6-phenylpyridine and 100 mL of anhydrous THF were added to the cooled, dried flask. The solution was cooled under nitrogen in a dry ice / acetone bath, and iodomethane-d3 (6 mL, 96.54 mmol) was added dropwise. The solution was stirred cold for 1 hour, then warmed to room temperature and left overnight. The solution was diluted with water and extracted twice with ethyl acetate. The organic layer was dried over magnesium sulfate, filtered, and evaporated. The crude substance was purified twice by column chromatography by dissolution with 2% ethyl acetate / hexane. 5.8 g (70%) of 2-phenyl-6-methyl-d3-pyridine was obtained.

[0151]

[0152] Synthesis of the dimer. A mixture of 2-phenyl-6-methyl(d3)pyridine (1.65 g, 9.58 mmol), iridium chloride (1.6 g, 4.35 mmol), and 30 mL of 2-ethoxyethanol was heated under nitrogen and refluxed overnight. The mixture was cooled to room temperature, and a red solid was filtered off. The solid was washed with methanol and hexane and air-dried in a fume hood. 1.09 g of dimer product (44%) was obtained, which could be used as is in the next step.

[0153]

[0154] Synthesis of trifluoromethanesulfonate intermediate. A mixture of dimer (1.09 g, 0.956 mmol) and 125 mL of dichloromethane was prepared in a 250 mL round-bottom flask. A methanol (10 mL) solution of silver trifluoromethanesulfonate (0.51 g, 2.00 mmol) was added to the red mixture, and the mixture turned green. The contents of the flask were stirred overnight at room temperature under nitrogen. The mixture was filtered through a diatomaceous earth mat, and the diatomaceous earth was washed with dichloromethane. The filtrate was evaporated to give a greenish-yellow solid. The solid was dried under high vacuum. 1 g of solid (71%) was obtained and used as is in the next reaction.

[0155]

[0156] Synthesis of compound 10. A trifluoromethanesulfonate complex (1 g, 1.3 mmol) and 2-phenyl-6-methyl(d3)pyridine (0.7 g, 4.0 mmol) were added to a 50 mL glass tube, which was then evacuated and refilled with nitrogen. This procedure was repeated, followed by heating the tube to 200 °C under nitrogen overnight. The tube was cooled, and dichloromethane was added to dissolve the material for transfer to a flask. The crude material was purified by column chromatography by dissolution with 20%, 40%, and 50% dichloromethane / hexane, followed by sublimation at 250 °C. Sublimation yielded 0.58 g of product (63%).

[0157] Example 2. Synthesis of compound 13

[0158]

[0159] Synthesis of 3-methyl-d3-2-phenylpyridine. 3-Bromo-2-phenylpyridine (9.9 g, 42 mmol) was dissolved in 100 mL of tetrahydrofuran and cooled to -78 °C. BuLi (26.4 mL, 1.6 M hexane solution) was added dropwise to the solution. After the addition was complete, the reaction mixture was stirred at -78 °C for 1 hour. Iodomethane-d3 (9.3 g, 63 mmol) was added, and the mixture was kept at room temperature for 2 hours. The reaction was then quenched with water and extracted with ethyl acetate. The crude product was purified by column chromatography using hexane and ethyl acetate as solvents. 2.3 g of pure product was obtained after purification.

[0160]

[0161] Synthesis of compound 13. 3-Methyl-d3-2-phenylpyridine (1.8 g, 10.4 mmol) and Ir(acac)3 (0.64 g, 1.3 mmol) were heated to 260 °C and maintained for 48 hours under nitrogen atmosphere. After cooling to room temperature, dichloromethane was added to dissolve the product. The dichloromethane solution was then poured into hexane. The precipitate was collected and passed through a silicone stopper. 0.6 g of product was given. The product was further purified by recrystallization from 1,2-dichlorobenzene.

[0162] Example 3. Synthesis of compound 27

[0163]

[0164] Synthesis of compound 27. A mixture of trifluoromethanesulfonate complex (1.4 g), 4-methyl-2,5-diphenylpyridine (1.5 g), and 50 mL of ethanol was heated to reflux under nitrogen overnight. The precipitate was filtered off. The crude substance was purified by column chromatography by dissolution in 50% dichloromethane / hexane. 1.1 g of the desired product was obtained.

[0165] Example 4. Synthesis of compound 43

[0166]

[0167] Synthesis of compound 43. Iridium trifluoromethanesulfonate complex (1.0 g, 1.3 mmol) and 2-biphenyl-4-methylpyridine (1.0 g, 4 mmol) were placed in a 100 mL round-bottom flask. 20 mL of a 50:50 solution of ethanol and methanol was added to the flask. The reaction mixture was refluxed and maintained for 8 hours. The reaction mixture was then cooled to room temperature. The reaction mixture was poured onto a silicon dioxide stopper and washed sequentially with ethanol and hexane. The filtrate was discarded. The stopper was then washed with dichloromethane to dissolve the product. The solvent was removed from the filtrate using a rotary evaporator. The product was further purified by column chromatography using dichloromethane and hexane (50:50) as the dissolving agent to give 0.5 g (50% yield) of the product.

[0168] Example 5. Synthesis of compound 50

[0169]

[0170] Synthesis of compound 50. Iridium trifluoromethanesulfonate complex (6.58 g, 9.2 mmol) and 4-(ethyl, d3)-2,5-diphenylpyridine (6.58 g, 25.0 mmol) were placed in a 1000 mL round-bottom flask. 140 mL of a 50:50 solution of ethanol and methanol was added to the flask. The reaction mixture was refluxed and maintained for 8 hours. The reaction mixture was then cooled to room temperature. The reaction mixture was poured onto a silicon dioxide stopper and washed sequentially with ethanol and hexane. The filtrate was discarded. The stopper was then washed with dichloromethane to dissolve the product. The solvent was removed from the filtrate using a rotary evaporator. The product was further purified by column chromatography using dichloromethane and hexane (50:50) as the dissolving agent to give 3.8 g (54% yield) of the product.

[0171] Device Example

[0172] All devices are manufactured by high-vacuum (<10⁻⁷ Torr) thermal evaporation. The anode is 1200 Å indium tin oxide (ITO). The cathode consists of 10 Å LiF followed by 1000 Å Al. Immediately after manufacturing, all devices are sealed in a nitrogen glove box (<1 ppm H₂O and O₂) with epoxy resin-sealed glass lids, and a moisture getter is included in the packaging.

[0173] Specific devices are provided in which the compounds of the present invention (compounds 10, 13 and 27) are luminescent dopants and H1 is the host. All device examples have an organic stack consisting of the following components in sequence from the ITO surface: 100 Å E1 as a hole injection layer (HIL), 300 Å 4,4'-bis[N-(1-naphthyl)-N-aniline]biphenyl (α-NPD) as a hole transport layer (HTL), 300 Å H1 (host material) doped with 7% or 10% of the compounds of the present invention as a luminescent layer (EML), 50 Å H1 as a blocking layer (BL), and 400 Å Alq3 (aluminum 8-hydroxyquinoline) as an ETL.

[0174] Comparative Examples 1-5 are manufactured similarly to the device examples, except that the materials used in the EML and BL are different. Specifically, E1, E2, or E3 are used as luminescent dopants in the EMLs of Comparative Examples 1 and 2, 3, 4, and 5, respectively. In addition, in Comparative Example 3, HPT is the BL material.

[0175] As used herein, the following compounds have the following structures:

[0176]

[0177]

[0178] Specific materials for use in OLEDs are provided. Specifically, these materials can be used as light-emitting dopants in the light-emitting layer (EML) of the device. The compounds provided herein can be used in devices to improve color, efficiency, and lifetime. Cmpd is an abbreviation for compound. Ex. is an abbreviation for example. Comp. is an abbreviation for comparison.

[0179]

[0180]

[0181]

[0182] As can be seen from device examples 1-6, the CD3 compound provided herein as a luminescent dopant provides a long lifetime. Specifically, the lifetime RT80% (defined as the time required for the device examples containing the provided compound to decay from the initial luminance L0 to 80% of its value at a constant current density of 40 mA / cd2 at room temperature) is significantly higher than that of the comparative examples containing the corresponding CH3-substituted compound. Specifically, compared to the RT80% of 165 h and 155 h of comparative examples 1 and 3 using the corresponding CH3-substituted compound (E1), compound 13 used in device examples 3 and 4 provides RT80% of 204 h and 220 h, respectively.

[0183] The foregoing information also demonstrates that the CD3-containing heterocyclic compounds provided herein can improve the lifetime and efficiency of the device. Specifically, the devices in Examples 5 and 6 containing compound 27 provide superior lifetime and efficiency compared to Comparative Examples 4 and 5 containing the corresponding CH3-substituted compound (E3). In particular, compound 27 provides 174h and 184h RT80% compared to 116h and 128h RT80% for the corresponding methyl-substituted compound E3.

[0184] Furthermore, the methyl-d3 substituted compounds provide improved device efficiency. Specifically, compounds 10, 13, and 27 achieve lower operating voltages than comparative examples using the corresponding CH3 substituted compounds. In particular, compounds 10, 13, and 27 provide operating voltages of 5.2V, 5.6V, and 4.9V, respectively, compared to 6.4V, 5.8V, and 5.1V.

[0185] The above information indicates that the methyl-d3 substituted compounds provided herein are excellent luminescent dopants for use in phosphorescent OLEDs. These compounds provide improved color, efficiency, and lifespan for the device.

[0186] As used herein, the following compounds have the following structures:

[0187]

[0188]

[0189]

[0190] As can be seen from apparatus examples 7 and 8, compound 43 has comparable efficiency and color to E4, and a longer apparatus life. Apparatus example 7 shows an LT80 of 374 h, while comparative example 6 shows a lifespan of 212 h. Apparatus example 8 shows an LT80 of 365 h, while comparative example 7 shows a lifespan of 283 h. Apparatus data indicate that the provided methyl-d3 substituted compound can extend apparatus life.

[0191] It should be understood that the various embodiments described herein are merely examples and are not intended to limit the scope of the invention. For example, many of the materials and structures described herein can be replaced by other materials and structures without departing from the spirit of the invention. Therefore, it will be apparent to those skilled in the art that the claimed invention may include variations of the specific examples and preferred embodiments described herein. It should be understood that the various theories regarding why the invention works are not intended to be limiting.

Claims

1. An organic light-emitting device comprising: an anode; a cathode; and an organic layer disposed between the anode and the cathode, wherein the organic layer comprises a compound having a deuterium-substituted ligand, wherein the deuterium is located within an alkyl chain.

2. The apparatus of claim 1, wherein the alkyl chain system is selected from the group consisting of C(D)(H)CH3, CD2CH3 and CH2CD2CH3.

3. The apparatus of claim 1 or 2, wherein the ligand further has methyl-d3 substitution.

4. The apparatus of claim 1 or 2, wherein the compound is a methyl-d3 substituted iridium complex.

5. The apparatus of claim 1 or 2, wherein the compound is a homopolymer or heteropolymer compound comprising CD3.

6. The apparatus of claim 1 or 2, wherein the organic layer is a light-emitting layer and the compound is a light-emitting dopant.

7. The apparatus of claim 6, wherein the organic layer further comprises a host.

8. A consumer product comprising the device as claimed in any one of claims 1 to 7.

9. The consumer products described in claim 8 are selected from the group consisting of flat panel displays, full-view displays and flexible displays.

10. The consumer products mentioned in claim 8 are selected from the group consisting of computer monitors, televisions, head-up displays, laptops and laser printers.

11. The consumer products mentioned in Request 8 are selected from the group consisting of telephones, mobile phones, personal digital assistants (PDAs), digital cameras, video recorders, viewfinders and microdisplays.

12. As in claim 8, the consumer products are selected from a group consisting of billboards, large walls, theater or sports stadium screens and signs.

13. As in claim 8, the consumer products are selected from a group of lamps used for indoor or outdoor lighting.

14. As in claim 8, the consumer products are selected from the group consisting of lights used for signaling and vehicles.

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