KR20130081240A - Highly efficient phosphorescent materials - Google Patents

Abstract

PURPOSE: A novel phosphorescent heteroleptic iridium complex with a substituted phenylquinoline ligand is provided to obtain a complex with improved properties through alkyl substitution on a phenylquinoline ligand when the complex is mixed in an organic light emitting diode (OLED) device. CONSTITUTION: A compound is denoted by chemical formula I. A first device contains a first organic light emitting device and further contains an anode, a cathode, and an organic layer placed between the anode and the cathode. The organic layer contains the compound of chemical formula I. The first device is consumption goods. The first device is an organic light emitting device. The first device contains a lighting panel. [Reference numerals] (AA) Chemical formula I

Description

Highly efficient phosphors {HIGHLY EFFICIENT PHOSPHORESCENT MATERIALS}

The present invention was completed and / or in place of and / or in accordance with the Joint Industry-Academic Research Agreement by one or more of the Regents of the University of Michigan, Princeton University, the University of Southern California, and the Universal Display Corporation. The Convention entered into force on the date of completion of the invention and prior to its date, and the invention was completed as a result of the activities carried out within the scope of the agreement.

The present invention relates to 2-phenylquinoline complexes of iridium, especially 2-phenylquinoline containing alkyl substituents having 4 or more carbon atoms. These iridium complexes are useful materials in OLED devices.

Optoelectronic devices using organic materials are becoming increasingly important for several reasons. Many of the materials used to fabricate such devices are relatively inexpensive, and organic optoelectronic devices have the potential to be economically advantageous over inorganic devices. In addition, the inherent properties of organic materials, such as their flexibility, can be very well suited for certain applications, such as on flexible substrates. Examples of organic optoelectronic devices include organic light emitting devices (OLEDs), organic phototransistors, organic photovoltaic cells, and organic photodetectors. In the case of OLEDs, organic materials may have performance advantages over conventional materials. For example, the wavelength at which the organic light emitting layer emits light can generally be readily controlled with suitable dopants.

OLEDs use organic thin films that emit light when a voltage is applied across the device. OLEDs are an increasingly important technology for use in applications such as flat panel displays, lighting and backlighting. Various OLED materials and shapes are described in U.S. Patent Nos. 5,844,363, 6,303,238, and 5,707,745, the disclosures of which are incorporated herein by reference in their entirety.

One application for phosphorescent molecules is the total color display. The industry standard for such displays requires pixels that are adjusted to emit a particular color referred to as a "saturation" color. In particular, these criteria require saturated red, green and blue pixels. The color may be measured using CIE coordinates known in the art.

An example of a green light emitting molecule is tris (2-phenylpyridine) iridium represented by Ir (ppy) ₃ having the following formula:

In such formulas and the following formulas in the present application, Applicants show a coordinate bond from nitrogen to metal (here Ir) in a straight line.

As used herein, the term "organic" includes not only polymeric materials that can be used to make organic optoelectronic devices, but also small molecule organic materials. "Small molecule" refers to any organic material that is not a polymer, and "small molecule" may actually be quite large. Small molecules may contain repeat units in some situations. For example, using a long chain alkyl group as a substituent does not remove the molecule from the "small molecule" type. The small molecule may also be introduced into the polymer, for example as a side chain group on the polymer backbone or as part of the backbone. The small molecule can also act as a core part of the dendrimer consisting of a series of chemical shells formed on the core part. The core portion of the dendrimer may be a fluorescent or phosphorescent small molecule emitter. The dendrimer may be a "small molecule ", and all the dendrimers conventionally used in the field of OLEDs have been found to be small molecules.

As used herein, "top" means farthest from the substrate and "bottom" means closest to the substrate. When the first layer is described as " located on top of the second layer ", the first layer is disposed away from the substrate. Other layers may be present between the first and second layers, unless the first layer is specified as "in contact" with the second layer. For example, the cathode may be described as "located on top of the anode" although there may be various organic layers between the cathode and the anode.

As used herein, "solution processibility" means that it can be dissolved, dispersed or transported in liquid medium in the form of a solution or suspension, and / or deposited from a liquid medium.

When the ligand is found to contribute directly to the photoactive properties of the luminescent material, the ligand can be referred to as "photoactive ". Although the auxiliary ligand may alter the nature of the photoactive ligand, the ligand may be referred to as "auxiliary" if it is found that the ligand does not contribute to the photoactive properties of the luminescent material.

As used herein, and as generally understood by those skilled in the art, when the first "highest occupied molecular orbital" (HOMO) or "lowest occupied molecular orbital" (LUMO) energy level is close to the vacuum energy level, 1 is "greater" or "higher" than the second HOMO or LUMO. Since the ionization potential (IP) is measured as negative energy with respect to the vacuum level, the higher HOMO energy level corresponds to an IP with a smaller absolute value (IP has a smaller negative value). Similarly, a higher LUMO energy level corresponds to an electron affinity (EA) with an absolute value smaller (the negative value of EA is smaller). In a typical energy level diagram with a vacuum level at the top, the LUMO energy level of the material is higher than the HOMO energy level of the same material. A "higher" HOMO or LUMO energy level is closer to the top of the diagram than a "lower" HOMO or LUMO energy level.

As used herein, and as generally understood by those skilled in the art, if the absolute value of the first work function is greater, then the first work function is "greater" or " . Since the work function is generally measured as a negative number with respect to the vacuum level, this means that the negative value of the "higher" work function is greater. In a typical energy level diagram with a vacuum level at the top, the "higher" work function is shown as being farther down from the vacuum level. Thus, the definition of HOMO and LUMO energy levels follows a treaty that is different from the work function.

The details of the OLED and the above definition can be found in U.S. Patent No. 7,279,704, the disclosure of which is incorporated herein by reference in its entirety.

In one embodiment, compounds of Formula I are provided:

<Formula I>

In the compounds of formula (I), R ₁ is selected from the group consisting of alkyl, cycloalkyl, heteroalkyl, aryl, heteroaryl and combinations thereof, wherein R ₁ has 4 or more carbon atoms. R, R ', R ₂ , R ₃ and R ₄ are independently hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, hetero Alkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acid, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino and combinations thereof. At least one of R ₂ , R _3, and R ₄ has two or more carbon atoms, and R and R ′ may represent mono, di, tri, tetra substitutions, or may be unsubstituted. Two adjacent R, R ₂ , R ₃ or R ₄ are optionally joined to form a ring, m being 1 or 2.

In one embodiment, the compound has the formula II:

&Lt;

In one embodiment, the compound has the formula III:

<Formula III>

In the above formula, R ₁ is selected from the group consisting of alkyl, cycloalkyl and combinations thereof. In one embodiment, m is 2.

In one embodiment, the compound has the formula II:

&Lt;

In the above formula, R ₅ and R ₆ are alkyl.

In one embodiment, the compound has the formula III:

<Formula III>

In one embodiment, R ₂ , R ₃ and R ₄ are independently selected from the group consisting of aryl, alkyl, hydrogen, deuterium and combinations thereof. In another embodiment, R ₂ , R ₃ and R ₄ are independently selected from the group consisting of methyl, CH (CH ₃ ) ₂ , CH ₂ CH (CH ₃ ) ₂ , phenyl, cyclohexyl and combinations thereof.

In one embodiment, R ₁ is alkyl. In one embodiment, R ₁ is selected from the group consisting of CH ₂ CH (CH ₃ ) ₂ , cyclopentyl, CH ₂ C (CH ₃ ) ₃ and cyclohexyl. In one embodiment, R ₁ is CH ₂ CH (CH ₃ ) ₂ .

In one embodiment, R ₃ is hydrogen or deuterium and R ₂ and R ₄ are independently selected from CH (CH ₃ ) ₂ and CH ₂ CH (CH ₃ ) ₂ .

In one embodiment, the compound is selected from the group consisting of compound 1 to compound 33.

In one embodiment, a first device is provided. The first device comprises a first organic light emitting device, further comprising an anode, a cathode, and an organic layer disposed between the anode and the cathode, the organic layer comprising a compound having Formula I:

<Formula I>

In the compounds of formula (I), R ₁ is selected from the group consisting of alkyl, cycloalkyl, heteroalkyl, aryl, heteroaryl and combinations thereof, wherein R ₁ has 4 or more carbon atoms. R, R ', R ₂ , R ₃ and R ₄ are independently hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, hetero Alkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acid, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino and combinations thereof. At least one of R ₂ , R _3, and R ₄ has two or more carbon atoms, and R and R ′ may represent mono, di, tri, tetra substitutions, or may be unsubstituted. Two adjacent R, R ₂ , R ₃ or R ₄ are optionally joined to form a ring, m being 1 or 2.

In one embodiment, the first device is a consumer. In another embodiment, the first device is an organic light emitting device. In one embodiment, the first device comprises an illumination panel.

In one embodiment, the organic layer further comprises a host. In one embodiment, the host comprises a metal 8-hydroxyquinolate. In one embodiment, the host is

And combinations thereof.

In general, an OLED comprises one or more organic layers disposed between and electrically connected to the anode and the cathode. When a current is applied, the anode injects holes into the organic layer (s) and the cathode injects electrons. The injected holes and electrons move inversely toward the charged electrodes, respectively. When electrons and holes are localized on the same molecule, an "exciton" is formed, which is a unionized electron-hole pair having an excited energy state. Light is emitted when the excitons are relaxed by the light emitting mechanism. In some cases, the excitons can be localized on the excimer or exciplex. Non-radiative mechanisms such as thermal relaxation may also occur but are generally considered undesirable.

Early OLEDs use luminescent molecules that emit light ("fluorescence") from a singlet state as disclosed, for example, in U.S. Patent No. 4,769,292, the disclosure of which is incorporated herein by reference in its entirety. Fluorescent emission generally occurs in a time period of less than 10 nanoseconds.

More recently, an OLED having a luminescent material that emits light from a triplet state ("phosphorescence") is illustrated. See 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 device based on electrophosphorescence," Appl. Phys. Lett. , vol. 75, No. 3, 4-6 (1999) ("Baldo-II"), the disclosures of which are incorporated herein by reference in their entirety. Phosphorescence is more specifically described in column 5-6 of U.S. Patent No. 7,279,704, which is incorporated by reference.

Figure 1 illustrates an organic light emitting device 100. 1 is not necessarily drawn to scale. The 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, and an electron transport layer ( 145, an electron injection layer 150, a protective layer 155, and a cathode 160. Cathode 160 is a compound cathode having a first conductive layer 162 and a second conductive layer 164. The device 100 may be fabricated by depositing a layer in the order described. The nature and function of the exemplary materials as well as these various layers are more specifically described in US Pat. No. 7,279,704, columns 6-10, which are incorporated by reference.

More examples for each of these layers are available. For example, a flexible and transparent substrate-anode combination is disclosed in U.S. Patent No. 5,844,363, which is incorporated herein by reference in its entirety. An example of a p-doped hole transport layer is m-MTDATA doped with F ₄ -TCNQ at a molar ratio of 50: 1, as disclosed in U.S. Patent Application Publication 2003/0230980, &Lt; / RTI &gt; Examples of luminescent and host materials are disclosed in U.S. Patent No. 6,303,238 (Thompson et al.), Which is incorporated herein by reference in its entirety. An example of an n-doped electron transport layer is BPhen doped with Li in a molar ratio of 1: 1, as disclosed in US Patent Application Publication No. 2003/0230980, which is incorporated by reference in its entirety. US Pat. Nos. 5,703,436 and 5,707,745, which are hereby incorporated by reference in their entirety, include cathodes, including compound cathodes having a thin layer of metal, such as Mg: Ag, having laminated transparent, electrically conductive sputter-deposited ITO layers. An example is disclosed. The theory and use of barrier layers are more specifically described in U.S. Patent No. 6,097,147 and U.S. Patent Application Publication No. 2003/0230980, which are incorporated herein by reference in their entirety. An example of an injection layer is provided in U.S. Patent Application Publication No. 2004/0174116, which is incorporated herein by reference in its entirety. A description of the protective layer can be found in U.S. Patent Application Publication No. 2004/0174116, which is incorporated herein by reference in its entirety.

FIG. 2 shows an inverted OLED 200. FIG. The device includes a substrate 210, a cathode 215, a light emitting layer 220, a hole transport layer 225, and an anode 230. Devices 200 may be fabricated by laminating layers in the order described. The most common OLED structure is that the device 200 may be referred to as an "inverted" OLED because the cathode is disposed above the anode and the device 200 is disposed with the cathode 215 below the anode 230. have. A material similar to that described with respect to device 100 may be used in the corresponding layer of device 200. Figure 2 provides an example of how some layers may be omitted from the structure of device 100.

It should be understood that the simple laminated structure shown in Figures 1 and 2 is provided by way of non-limiting example, and that embodiments of the present invention may be used in conjunction with various other structures. The particular materials and structures described are for illustration purposes only and other materials and structures may be used. Functional OLEDs may be achieved by combining the various layers described in different ways, or the layers may be entirely omitted based on design, performance and cost factors. Other layers not specifically described may also be included. Materials other than those specifically described can be used. While many of the examples provided herein describe various layers as including a single material, a mixture of materials, such as a host and a dopant, or more generally a mixture, may be used. In addition, the layer may have a plurality of underlying layers. The nomenclature presented in the various layers herein is not intended to be strictly limiting. For example, in the device 200, the hole transporting layer 225 transports holes, injects holes into the light emitting layer 220, and can be described as a hole transporting layer or a hole injecting layer. In one embodiment, an OLED can be described as having an "organic layer" disposed between the cathode and the anode. Such an organic layer may comprise a single layer or may further comprise a plurality of layers of different organic materials as described, for example, in connection with Figs. 1 and 2.

Structures and materials not specifically described, such as OLEDs, including polymeric materials (PLEDs) as described in US Pat. No. 5,247,190 (Friend et al.), Can be used, which is incorporated by reference in its entirety. Included. As a further example, an OLED having a single organic layer can be used. OLEDs may be deposited, for example, as described in U.S. Patent No. 5,707,745 (Forrest et al.), Which is incorporated herein by reference in its entirety. The OLED structure may deviate from the simple laminated structure shown in Figs. 1 and 2. For example, the substrate may have a mesa structure as described in US Pat. No. 6,091,195 (Forrest et al.) And / or a pit structure described in US Pat. No. 5,834,893 (Bulovic et al.). Angled reflective surfaces for improving the same out-coupling may be included, these patent documents being incorporated herein by reference in their entirety.

Unless otherwise stated, any layer of the various embodiments may be deposited by any suitable method. For organic layers, preferred methods include thermal evaporation, ink-jet, US Pat. No. 6,337,102 as described in US Pat. Nos. 6,013,982 and 6,087,196, which are incorporated herein by reference in their entirety. al.) Organic Vapor Phase Deposition (OVPD), as described in US Patent Application No. 10 / 233,470, which is incorporated herein by reference in its entirety. Deposition by organic vapor jet printing (OVJP), as described in (included). Other suitable deposition methods include spin coating and other solution-based processes. The solution-based process is preferably carried out in nitrogen or an inert atmosphere. For other layers, the preferred method involves thermal evaporation. Preferred patterning methods include deposition via a mask, cold welding as described in U.S. Patent Nos. 6,294,398 and 6,468,819, which are incorporated herein by reference, and some deposition such as ink-jet and OVJD And pattern formation associated with the method. The material to be deposited may be modified to have compatibility with a particular deposition method. For example, substituents such as alkyl and aryl groups, branched or unbranched, preferably comprising three or more carbons, can be used in small molecules to improve the processing capacity of their solution processing. Substituents having 20 or more carbons can be used, with 3 to 20 carbons being preferred. Materials having an asymmetric structure may have better solution processability than having a symmetric structure, because the asymmetric material may have a low tendency to recrystallize. Dendrimer substituents can be used to enhance the ability of small molecules to process solution processing.

Devices manufactured according to embodiments of the present invention may be used in various applications such as flat panel displays, computer monitors, medical monitors, televisions, billboards, lights for indoor or outdoor lighting and / or signaling, heads up displays, May be incorporated into a variety of consumer goods including printers, telephones, mobile phones, personal digital assistants (PDAs), laptop computers, digital cameras, camcorders, viewfinders, microdisplays, automobiles, gigantic walls, theaters or stadium screens or signage. Various adjustment mechanisms, including passive matrix and active matrix, may be used to adjust the device according to the present invention. Many devices are intended to be used in a temperature range that is comfortable to humans, such as 18 ° C. to 30 ° C., more preferably at room temperature (20 ° C. to 25 ° C.).

The materials and structures described herein may have applications in devices other than OLEDs. For example, other optoelectronic devices such as organic solar cells and organic photodetectors can use materials and structures. More generally, organic devices, such as organic transistors, can use materials and structures.

The terms halo, halogen, alkyl, cycloalkyl, alkenyl, alkynyl, arylalkyl, heterocyclic groups, aryls, aromatic groups and heteroaryls are known in the art and defined in US Pat. No. 7,279,704 in columns 31-32. This patent document is incorporated herein by reference in its entirety.

Figure 1 shows an organic light emitting device.
Figure 2 shows an inverted organic light emitting device without a separate electron transport layer.
Figure 3 shows the compounds of formula (I).

In one embodiment, compounds of Formula (I) are provided:

<Formula I>

In the compounds of formula (I), R ₁ is selected from the group consisting of alkyl, cycloalkyl, heteroalkyl, aryl, heteroaryl and combinations thereof, wherein R ₁ has 4 or more carbon atoms. R, R ', R ₂ , R ₃ and R ₄ are independently hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, hetero Alkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acid, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino and combinations thereof. At least one of R ₂ , R _3, and R ₄ has two or more carbon atoms, and R and R ′ may represent mono, di, tri, tetra substitutions, or may be unsubstituted. Two adjacent R, R ₂ , R ₃ or R ₄ are optionally joined to form a ring, m being 1 or 2.

As discussed in the Device Examples section below, surprisingly, when R ₁ is an alkyl group containing at least 4 carbons and at least one of R ₂ -R ₄ has at least 2 carbons, the resulting iridium complex is It has been found that it can be used to create OLED devices with good properties. Compounds of formula (I) are superior to compounds having only R ₁ having at least 4 carbons or at least _one of R ₂ -R ₄ has at least 2 carbons. The above-mentioned substitution pattern is judged to have a synergy. Without being bound to a particular theory, alkyl groups are packed in the crystal lattice of compounds of formula (I) such that when these compounds are used in OLED devices, the resulting devices have improved operational variables such as increased luminous efficiency and narrow emission spectrum. It is believed to have an impact on.

In one embodiment, the compound has the formula II:

&Lt;

In one embodiment, the compound has formula III:

<Formula III>

In the above formula, R ₁ is selected from the group consisting of alkyl, cycloalkyl and combinations thereof. In one embodiment, m is 2.

In one embodiment, the compound has the formula II:

&Lt;

In the above formula, R ₅ and R ₆ are alkyl.

In one embodiment, the compound has formula III:

<Formula III>

In one embodiment, R ₂ , R ₃ and R ₄ are independently selected from the group consisting of aryl, alkyl, hydrogen, deuterium and combinations thereof. In another embodiment, R ₂ , R ₃ and R ₄ are independently selected from the group consisting of methyl, CH (CH ₃ ) ₂ , CH ₂ CH (CH ₃ ) ₂ , phenyl, cyclohexyl and combinations thereof.

In one embodiment, R ₁ is alkyl. In one embodiment, R ₁ is selected from the group consisting of CH ₂ CH (CH ₃ ) ₂ , cyclopentyl, CH ₂ C (CH ₃ ) ₃ and cyclohexyl. In one embodiment, R ₁ is CH ₂ CH (CH ₃ ) ₂ .

In one embodiment, R ₃ is hydrogen or deuterium and R ₂ and R ₄ are independently selected from CH (CH ₃ ) ₂ and CH ₂ CH (CH ₃ ) ₂ .

In one embodiment, the compound is selected from the group consisting of:

In one embodiment, a first device is provided. The first device comprises a first organic light emitting device, further comprising an anode, a cathode, and an organic layer disposed between the anode and the cathode, the organic layer comprising a compound having Formula I:

<Formula I>

In the compounds of formula (I), R ₁ is selected from the group consisting of alkyl, cycloalkyl, heteroalkyl, aryl, heteroaryl and combinations thereof, wherein R ₁ has 4 or more carbon atoms. R, R ', R ₂ , R ₃ and R ₄ are independently hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, hetero Alkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acid, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino and combinations thereof. At least one of R ₂ , R _3, and R ₄ has two or more carbon atoms, and R and R ′ may represent mono, di, tri, tetra substitutions, or may be unsubstituted. Two adjacent R, R ₂ , R ₃ or R ₄ are optionally joined to form a ring, m being 1 or 2.

In one embodiment, the first device is a consumer. In one embodiment, the first device is an organic light emitting device. In one embodiment, the first device comprises a light emitting panel.

In one embodiment, the organic layer further comprises a host. In one embodiment, the host comprises a metal 8-hydroxyquinolate. In one embodiment, the host is

And combinations thereof.

Device Embodiment

All devices were manufactured by high vacuum (<10 ⁻⁷ Torr) thermal evaporation (VTE). The anode electrode is 1,200 Pa of indium tin oxide (ITO). The cathode consisted of 10 kW of LiF followed by 1,000 kW of Al. All devices are encapsulated with an epoxy resin sealed glass lid in a nitrogen glove box (<1 ppm H ₂ O and O ₂ ) immediately after manufacture, and the moisture getter is incorporated into the package.

The organic laminate of the device example is 300 kV of 4,4'-bis [N- (1-naphthyl) -N-phenylamino] as a hole injection layer (HIL) and a hole transport layer (HTL) of 100 kV from the ITO surface. Sequentially made up of biphenyl (α-NPD), 300 μs host doped with 9% Compound 1 or Compound 2 as EML and 400 μs Alq ₃ (tris-8-hydroxyquinoline aluminum) as ETL .

As used herein, the following compounds have the structure:

The device structure is provided in Table 1 below, and the corresponding device data is provided in Table 2 below.

Table 1

Table 2

를 함유하며, R₂ 및 R₄는 1개의 탄소 원자를 갖는 알킬 기이다.It can be seen from Table 2 that device examples containing compounds of formula I, such as compounds 1 and 2, have higher luminous efficiency and very narrow emission spectra compared to Comparative Examples 1 and 2, and Comparative Examples 1 and 2 They have smaller alkyl groups on phenylquinoline or acac-type ligands (acac is acetylacetone). Compound A and Compound 1 have 4 carbon alkyl substituents at the 7-position of the heterocyclic ring. However, Compound A in Comparative Example 1 is a ligand

And R ₂ and R ₄ are alkyl groups having one carbon atom.

Unexpectedly, as the carbon chain lengths of R ₂ and R ₄ increase from one carbon to two or three carbon atoms, the luminous efficiency increases, incorporating these longer carbon chains (ie, compounds of formula I) FWHM (full width at half maximum) is reduced in the device. For example, using compound 2 in device example 2, the luminous efficiency of example 2 is increased from 26.2 cd / A to 26.4 cd / A, and the FWHM is reduced from 60 nm to 52 nm. As the carbon chain lengths of R ₂ and R ₄ increase from three to four in compound 1 of device example 1, the luminescence of device example 1 is increased to 28.9 cd / A and the FWHM is narrow to 52 nm. In addition, Comparative Example 2 contains Compound B with the same acac-type ligand as Compound 1 in Device Example 1. However, Compound B in Comparative Example 2 does not have any alkyl substitution at the 7-position of the heterocyclic ring having 4 or more carbons in the alkyl group, whereas Compound 1 has such an alkyl group. The luminous efficiency of Compound 1 of Device Example 1 is 28.9 cd / A, whereas Compound B of Comparative Example 2 is 21.9 cd / A. Thus, unexpectedly, iridium complexes containing acac-type ligands having alkyl substituents having two or more carbons and phenylquinoline ligands having alkyl groups having four or more carbons at the 7-position may be used in compounds of the OLED device. Create synergistic combinations of properties that make them useful.

Combination with other substances

The materials described herein as being useful for a particular layer in an organic light emitting device can be used in combination with various other materials present in the device. For example, the luminescent dopants disclosed herein may be used in combination with a host, a transport layer, a barrier layer, an implant layer, an electrode, and other layers that may be present. The materials described or referred to below are non-limiting materials that may be useful in combination with the compounds disclosed herein and one of ordinary skill in the art can readily reference literature identifying other materials that may be useful in combination .

HIL Of HTL :

The hole injecting / transporting material to be used in the present invention is not particularly limited, and any compound may be used as long as the compound is used as a hole injecting / transporting material. Non-limiting examples of materials include phthalocyanine or porphyrin derivatives; Aromatic amine derivatives; Indolocarbazole derivatives; Polymers comprising fluorohydrocarbons; A polymer having a conductive dopant; Conductive polymers such as PEDOT / PSS; Self-assembled monomers derived from compounds such as phosphonic acids and silane derivatives; Metal oxide derivatives such as MoO _x ; p-type semiconductor organic compounds such as 1,4,5,8,9,12-hexaazatriphenylene hexacarbonitrile; Metal complexes and crosslinking compounds.

Non-limiting examples of aromatic amine derivatives used in HIL or HTL include the following:

Each of Ar ¹ to Ar ⁹ is an aromatic hydrocarbon ring compound such as benzene, biphenyl, triphenyl, triphenylene, naphthalene, anthracene, phenalene, phenanthrene, fluorene, pyrene, ; Benzothiophene, benzoselenophene, carbazole, indolocarbazole, pyridylindole, pyrrolodipyridine, pyrazole, pyrazole, pyrrolidine, pyrazole, Oxadiazole, oxadiazole, oxadiazole, oxadiazole, thiadiazole, pyridine, pyridazine, pyrimidine, pyrazine, triazine, oxazine, oxathiazine, oxadiazole, Benzothiazole, benzothiazole, quinoline, isoquinoline, cyanol, quinazoline, quinoxaline, naphthyridine, phthalazine, pteridine, benzothiazole, benzothiazole, benzothiazole, Aromatic heterocyclic compounds such as xanthene, acridine, phenazine, phenothiazine, phenoxy, benzofuropyridine, furodipyridine, benzothienopyridine, thienodipyridine, benzoselenophenopyridine and selenophenodipyridine Group of compounds; And an aromatic heterocyclic group and an aromatic heterocyclic group, and may be a group of the same type or different type selected from the group consisting of an oxygen atom, a nitrogen atom, a sulfur atom, a silicon atom, a phosphorus atom, a boron atom, a chain structural unit and an aliphatic cyclic group Or from 2 to 10 cyclic structural units bonded directly or through at least one of these. Wherein each Ar is hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, Further substituted with a substituent selected from the group consisting of acyl, carbonyl, carboxylic acid, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino and combinations thereof.

In one embodiment, Ar ¹ to Ar ⁹ are independently

로 이루어진 군으로부터 선택된다.

&Lt; / RTI &gt;

k is an integer from 1 to 20; X ¹ to X ⁸ are C (including CH) or N; Ar ¹ has the same group as defined above.

Non-limiting examples of metal complexes used in HIL or HTL include:

M is a metal having an atomic weight greater than 40; (Y ¹ -Y ² ) is a bidentate ligand, Y ¹ and Y ² are independently selected from C, N, O, P and S; L is an auxiliary ligand; m is an integer from 1 to the maximum number of ligands that can be attached to the metal; m + n is the maximum number of ligands that can be bonded to the metal.

In one embodiment, (Y ¹ -Y ² ) is a 2-phenylpyridine derivative.

In yet another embodiment, (Y &lt; ¹ &gt; -Y &lt; ² &gt;) is a carbenic ligand.

In yet another embodiment, M is selected from Ir, Pt, Os, and Zn.

In a further embodiment, the metal complex has a minimum oxidation potential in solution of less than about 0.6 V versus Fc ⁺ / Fc couple.

Host:

The light emitting layer of the organic EL device of the present invention may preferably include at least a metal complex as a light emitting material and a host material using a metal complex as a dopant material. Examples of host materials include, but are not limited to, any metal complex or organic compound that can be used if the host's triplet energy is greater than that of the dopant. The table below categorizes host materials as preferred for devices that emit various colors, and any host material can be used with any dopant as long as it meets triplet criteria.

Examples of metal complexes used as hosts are preferably those having the formula:

M is a metal; (Y ³ -Y ⁴ ) is a bidentate ligand, Y ³ and Y ⁴ are independently selected from C, N, O, P and S; L is an auxiliary ligand; m is an integer value from 1 to the maximum number of ligands to which a metal can be bound; m + n is the maximum number of ligands that can be bonded to the metal.

이다.In one embodiment, the metal complex is

to be.

(O-N) is a bidentate ligand having a metal coordinated to atoms O and N.

In yet another embodiment, M is selected from Ir and Pt.

In a further embodiment, (Y ³ -Y ⁴ ) is a carbenic ligand.

Examples of organic compounds used as a host include aromatic hydrocarbon cyclic compounds such as benzene, biphenyl, triphenyl, triphenylene, naphthalene, anthracene, phenalene, phenanthrene, fluorene, pyrene, A group of Jules; Aromatic heterocyclic compounds such as dibenzothiophene, dibenzofuran, dibenzoselenophene, furan, thiophene, benzofuran, benzothiophene, benzoselenophene, carbazole, indolocarbazole, pyridylindole, Oxadiazole, oxathiazole, dioxazole, thiadiazole, pyridine, pyridazine, pyrimidine, pyrazine, triazine, oxazine, oxazole, thiadiazole, pyridazine, , Oxathiazine, oxadiazine, indole, benzimidazole, indazole, phosphorus, benzoxazole, benzisoxazole, benzothiazole, quinoline, isoquinoline, cinnoline, quinazoline, quinoxaline, naphthyridine Benzothienopyridine, benzoselenophenopyridine, and selenophenodine, such as benzothiophene, benzothiophene, benzothiophene, benzothiophene, Pyridine; And an aromatic hydrocarbon ring group and an aromatic heterocyclic group and may be bonded directly to each other and may be bonded to each other directly or through an oxygen atom, a nitrogen atom, a sulfur atom, a silicon atom, a phosphorus atom, a boron atom, And from 2 to 10 cyclic structural units bonded by at least one of aliphatic cyclic groups. Wherein each group is hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl Further substituted with a substituent selected from the group consisting of carbonyl, carboxylic acid, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino and combinations thereof.

In one embodiment, the host compound comprises at least one of the following groups in the molecule:

R ¹ to R ⁷ are independently hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, Heteroaryl, acyl, carbonyl, carboxylic acid, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino and combinations thereof, and in the case of aryl or heteroaryl, the aforementioned Ar Has a similar definition.

k is an integer of 0 to 20;

X ¹ to X ⁸ are selected from C (including CH) or N;

Z ¹ and Z ² are selected from NR ¹ , O or S.

HBL:

The hole blocking layer (HBL) may be used to reduce the number of holes and / or excitons emitted from the light emitting layer. The presence of such a barrier layer in the device may result in a higher efficiency than a similar device substantially lacking the barrier layer. In addition, the blocking layer may be used to define emission to a predetermined portion of the OLED.

In one embodiment, the compound used for HBL comprises the same functional group used as the host described above.

In another embodiment, the compound used in HBL comprises at least one of the following groups in the molecule:

k is an integer from 0 to 20; L is an auxiliary ligand and m is an integer from 1 to 3.

ETL:

The electron transport layer (ETL) may comprise a material capable of transporting electrons. The electron transporting layer may be intrinsic (undoped) or doped. Doping can be used to improve conductivity. Examples of ETL materials are not particularly limited, and any metal complex or organic compound can be used as long as it is commonly used to transport electrons.

In one embodiment, the compound used for ETL comprises one or more of the following groups in the molecule:

R ¹ is hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, Selected from the group consisting of carbonyl, carboxylic acid, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof. Have

Ar ¹ to Ar ³ has a similar definition to Ar ′ described above.

k is an integer of 0 to 20;

X ¹ to X ⁸ are selected from C (including CH) or N;

In another embodiment, the metal complex used in the ETL includes, but is not limited to, the following chemical formulas:

(O-N) or (N-N) is a bidentate ligand with a metal coordinated to atoms O, N or N, N; L is an auxiliary ligand; m is an integer value from 1 to the maximum number of ligands that may be attached to the metal.

In any of the aforementioned compounds used in each layer of the OLED device, the hydrogen atom may be partially or fully dehydrated.

A number of hole injecting materials, hole transporting materials, host materials, dopant materials, exciton / hole blocking layer materials, electron transporting and electron injecting materials may be used in OLEDs in addition to and / or in combination with the materials disclosed herein. Non-limiting examples of materials that can be used in OLEDs in combination with the materials disclosed herein are set forth in Table 3 below. Table 3 sets forth non-limiting types of materials, non-limiting examples of compounds for each type, and references that disclose materials.

TABLE 3

Experiment

As used herein, the chemical abbreviations are as follows: Cy is cyclohexyl, dba is dibenzylideneacetone, EtOAc is ethyl acetate, DME is dimethoxyethane, dppe is 1,2-bis (diphenylphosphino) ethane, THF Is tetrahydrofuran, DCM is dichloromethane, S-Phos is dicyclohexyl (2 ', 6'-dimethoxy- [1,1'-biphenyl] -2-yl) phosphine.

Synthesis of Compound 1

Step 1

2-Amino-4-chlorobenzoic acid (42.8 g, 0.25 mol) was dissolved in 200 mL of anhydrous THF and cooled in an ice water bath. Lithium aluminum hydride chips (11.76 g, 0.31 mol) were added to the solution. The resulting mixture was stirred at rt for 8 h. Water (12 mL) was added followed by 12 g 15% NaOH followed by an additional 36 mL of water. The slurry was stirred at room temperature for 30 minutes and then filtered. The filtered solid was washed with ethyl acetate. The liquids were combined and the solvent evaporated to yield crude product, which was used without purification in the next step.

Step 2

2-amino-4-chlorophenylmethanol (6.6 g, 0.04 mol), 1- (3,5-dimethylphenyl) ethanone (10.0 g, 0.068 mol), RuCl ₂ (PPH ₃ ) ₃ (0.1 g, 12 mmol ) And 2.4 g (0.043 mol) of KOH were refluxed in 100 ml of toluene for 10 hours. Water was collected from the reaction using a Dean-Stark trap. After cooling the reaction to room temperature, the mixture was filtered through a silica gel plug. The product was further purified by column chromatography using 2% ethyl acetate in hexane as eluent to afford 9 g of product. After chromatography the product was further recrystallized from isopropanol to yield 5 g (50%) of the desired product.

Step 3

7-chloro-2- (3,5-dimethylphenyl) quinoline (3.75 g, 0.014 mol), isobutylboronic acid (2.8 g, 0.028 mol), Pd ₂ (dba) ₃ (1 mol%), 2-dish Clohexylphosphino-2 ', 6'-dimethoxybiphenyl (S-Phos) (4 mol%), potassium phosphate monohydrate (16.0 g) and 100 ml of toluene were added to a 250 ml round bottom flask. Nitrogen was bubbled into the reaction mixture for 20 minutes and the mixture was heated to reflux overnight for 18 hours. The reaction mixture was allowed to cool to room temperature and the crude product was purified by column chromatography using 2% ethyl acetate in hexane as solvent to afford 3.6 g (90%) of the desired product after evaporation of the solvent.

Step 4

Ligand (4.6 g, 16 mmol), 2-ethoxyethanol (25 mL) and water (5 mL) from step 3 were added to a 1 L three neck round bottom flask. Nitrogen was bubbled into the reaction mixture for 45 minutes. Then IrCl ₃ H ₂ O (1.2 g, 3.6 mmol) was added and the reaction mixture was heated to reflux for 17 h under nitrogen. The reaction mixture was cooled to rt and filtered. The dark red residue was washed with methanol (2 × 25 mL) followed by hexane (2 × 25 mL) and dried in a vacuum oven to yield 1.3 g (87%) of dichlorocrosslinked iridium dimer.

Step 5

N, N-dimethylformamide (DMF) (1 L) and potassium tert-butoxy (135.0 g 1.2 mol) were heated to 50 ° C. under nitrogen. Methyl 3-methylbutanoate (86.0 g, 0.75 mol) was added dropwise from the dropping funnel, followed by dropwise addition of a solution of 4-methylpentan-2-one (50 g, 1 mol) in 100 mL DMF. The progress of the reaction was monitored by GC. When the reaction was complete, the mixture was cooled to room temperature and slowly neutralized with 20% H ₂ SO ₄ solution. Water (300 mL) was added and two layers formed. The layer containing 2,8-dimethylnonane-4,6-dione was purified using vacuum distillation to give 40 g (43% yield) of pink oil.

Step 6

Dichlorocrosslinked iridium dimer (1.0 g, 0.6 mmol) from step 4, 2,8-dimethylnonan-4,6-dione (0.8 g, 6 mmol), Na ₂ CO ₃ (3 g, 12 mmol) and 25 mL 2-ethoxyethanol was placed in a 250 mL round bottom flask. After the reaction mixture was stirred at room temperature for 24 hours, 2 g of Celite ^® and 200 ml of dichloromethane were added to the reaction mixture to dissolve the product. The mixture was filtered through a layer of Celite ^® . The filtrate was passed through a silica / alumina plug and washed with dichloromethane. The cleared solution was filtered through GF / F filter paper and the filtrate was heated to remove most of the dichloromethane. Isopropanol (20 mL) was then added, the slurry was cooled to room temperature, the product was filtered off, washed with isopropanol and dried to give 1.1 g (97% yield) of the crude product. This product was recrystallized twice from dichloromethane and then sublimed to give compound 1.

Synthesis of Compound 2

Dichlorocrosslinked iridium dimer (2.75 g, 1.71 mmol) from step 4 from the synthesis, 2,6-dimethylheptan-3,5-dione (2.67 g, 17.1 mmol), K ₂ CO ₃ (2.3 g, 34.2 mmol) and 25 mL 2-ethoxyethanol were placed in a 250 mL round bottom flask. The reaction mixture was stirred at room temperature for 24 hours, after which 2 g of Celite ^® and 200 mL of dichloromethane were added to the reaction mixture to dissolve the product. The mixture was filtered through a layer of Celite ^® . The filtrate was passed through a silica / alumina plug and washed with dichloromethane. The cleared solution was filtered through GF / F filter paper and the filtrate was heated to remove most of the dichloromethane. Isopropanol (20 mL) was then added, the slurry was cooled to room temperature, the product was filtered off, washed with isopropanol and dried to give 1.49 g (97% yield) of the crude product. After recrystallization of this product twice, sublimation gave compound 2.

It is to be understood that the various embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention. For example, many of the materials and structures described herein may be substituted with other materials and structures without departing from the spirit of the invention. The invention as claimed includes modifications from the specific examples and preferred embodiments described herein as will be apparent to those skilled in the art. It should be understood that the various theories relating to why the present invention operates are not intended to be limiting.

Claims (20)

A compound of formula (I)
(I)

In the above formula, R ₁ is selected from the group consisting of alkyl, cycloalkyl, heteroalkyl, aryl, heteroaryl, and combinations thereof, wherein R ₁ has 4 or more carbon atoms;
R, R ', R ₂ , R ₃ and R ₄ are independently hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, hetero Alkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acid, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino and combinations thereof;
At least one of R ₂ , R ₃ and R ₄ has two or more carbon atoms,
R and R 'may represent mono, di, tri, tetra substitutions or unsubstitution;
Two adjacent R, R ₂ , R ₃ or R ₄ are optionally joined to form a ring,
m is 1 or 2. The compound of claim 1 having the formula II:
<Formula II>

The compound of claim 1 having the formula III:
(III)

In the above formula, R ₁ is selected from the group consisting of alkyl, cycloalkyl and combinations thereof. The compound of claim 1, wherein m is 2. The compound of claim 3 having the formula II:
<Formula II>

In the above formula, R ₅ and R ₆ are alkyl. The compound of claim 5 having the formula III:
(III)

The compound of claim 1, wherein R ₂ , R ₃ and R ₄ are independently selected from the group consisting of aryl, alkyl, hydrogen, deuterium and combinations thereof. 8. The compound of claim 7, wherein R ₂ , R ₃ and R ₄ are independently selected from the group consisting of methyl, CH (CH ₃ ) ₂ , CH ₂ CH (CH ₃ ) ₂ , phenyl, cyclohexyl and combinations thereof. compound. The compound of claim 5, wherein R ₁ is alkyl. The compound of claim 9, wherein R ₁ is selected from the group consisting of CH ₂ CH (CH ₃ ) ₂ , cyclopentyl, CH ₂ C (CH ₃ ) _3, and cyclohexyl. The compound of claim 10, wherein R ₁ is CH ₂ CH (CH ₃ ) ₂ . The compound of claim 8, wherein R ₃ is hydrogen or deuterium and R ₂ and R ₄ are independently selected from CH (CH ₃ ) ₂ and CH ₂ CH (CH ₃ ) ₂ . 2. The compound according to claim 1, wherein the compound is selected from the group consisting of:

A first organic light emitting device,
Anode,
The cathode and
A first device, disposed between an anode and a cathode, further comprising an organic layer comprising a compound having Formula I:
(I)

In the above formula, R ₁ is selected from the group consisting of alkyl, cycloalkyl, heteroalkyl, aryl, heteroaryl, and combinations thereof, wherein R ₁ has 4 or more carbon atoms;
R, R ', R ₂ , R ₃ and R ₄ are independently hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, hetero Alkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acid, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino and combinations thereof;
At least one of R ₂ , R ₃ and R ₄ has two or more carbon atoms,
R and R 'may represent mono, di, tri, tetra substitutions or unsubstitution;
Two adjacent R, R ₂ , R ₃ or R ₄ are optionally joined to form a ring,
m is 1 or 2. The first device of claim 14, wherein the first device is consumer goods. The first device of claim 14, wherein the first device is an organic light emitting device. The first device of claim 14 comprising a lighting panel. The first device of claim 14, wherein the organic layer further comprises a host. The first device of claim 18, wherein the host comprises a metal 8-hydroxyquinolate. 19. The device of claim 18, wherein the host is

And a combination thereof.

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