ORGANIC ELECTROLUMINESCENT MATERIALS AND DEVICES

Provided are OLEDs that are designed with a specific material sets that minimize the lifetime degradation of the OLED at elevated temperatures, where the features of such OLED are defined by a ratio ΔLT defined as (LT90 of the OLED measured at 40° C.)/(LT90 of an identical OLED measured at 20° C.) when each of the OLED and the identical OLED is run at the same current density; wherein the resulting ΔLT is greater than 0.4.

FIELD

The present disclosure generally relates to organic light emitting devices and their uses in electronic devices including consumer products.

BACKGROUND

Opto-electronic devices that make use of organic materials are becoming increasingly desirable for various reasons. Many of the materials used to make such devices are relatively inexpensive, so organic opto-electronic devices have the potential for cost advantages over inorganic devices. In addition, the inherent properties of organic materials, such as their flexibility, may make them well suited for particular applications such as fabrication on a flexible substrate. Examples of organic opto-electronic devices include organic light emitting diodes/devices (OLEDs), organic phototransistors, organic photovoltaic cells, and organic photodetectors. For OLEDs, the organic materials may have performance advantages over conventional materials.

OLEDs make use of thin organic films that emit light when voltage is applied across the device. OLEDs are becoming an increasingly interesting technology for use in applications such as flat panel displays, illumination, and backlighting.

SUMMARY

In one aspect, the present disclosure provides an organic light emitting device (OLED) comprising: a first electrode and a second electrode with an organic layer stack between the electrodes; wherein the organic layer stack comprises an emissive layer; and the emissive layer comprises at least one emitter; and the ratio of the lifetime of the OLED device at 40 degree Celsius to the lifetime of an identical OLED device at 20 degree Celsius is defined as ΔLT when each OLED is run at the same current density; and ΔLT is greater than 0.4.

In another aspect, the present disclosure provides a consumer product comprising an OLED as defined herein.

DETAILED DESCRIPTION

The term “ester” refers to a substituted oxycarbonyl (—O—C(O)—Rsor —C(O)—O—Rs) radical.

The term “ether” refers to an —ORsradical.

The term “selenyl” refers to a —SeRsradical.

The term “sulfinyl” refers to a —S(O)—Rsradical.

The term “sulfonyl” refers to a —SO2—Rsradical.

The term “phosphino” refers to a —P(Rs)2radical, wherein each Rscan be same or different.

The term “silyl” refers to a —Si(Rs)3radical, wherein each Rscan be same or different.

The term “germyl” refers to a —Ge(Rs)3radical, wherein each Rscan be same or different.

The term “boryl” refers to a —B(Rs)2radical or its Lewis adduct —B(Rs)3radical, wherein Rscan be same or different.

The term “alkenyl” refers to and includes both straight and branched chain alkene radicals. Alkenyl groups are essentially alkyl groups that include at least one carbon-carbon double bond in the alkyl chain. Cycloalkenyl groups are essentially cycloalkyl groups that include at least one carbon-carbon double bond in the cycloalkyl ring. The term “heteroalkenyl” as used herein refers to an alkenyl radical having at least one carbon atom replaced by a heteroatom. Optionally the at least one heteroatom is selected from O, S, N, P, B, Si, and Se, preferably, O, S, or N. Preferred alkenyl, cycloalkenyl, or heteroalkenyl groups are those containing two to fifteen carbon atoms. Additionally, the alkenyl, cycloalkenyl, or heteroalkenyl group may be optionally substituted.

The term “alkynyl” refers to and includes both straight and branched chain alkyne radicals. Alkynyl groups are essentially alkyl groups that include at least one carbon-carbon triple bond in the alkyl chain.

Preferred alkynyl groups are those containing two to fifteen carbon atoms. Additionally, the alkynyl group may be optionally substituted.

The terms “aralkyl” or “arylalkyl” are used interchangeably and refer to an alkyl group that is substituted with an aryl group. Additionally, the aralkyl group may be optionally substituted.

The term “heterocyclic group” refers to and includes aromatic and non-aromatic cyclic radicals containing at least one heteroatom. Optionally the at least one heteroatom is selected from O, S, N, P, B, Si, and Se, preferably, O, S, or N. Hetero-aromatic cyclic radicals may be used interchangeably with heteroaryl.

Preferred hetero-non-aromatic cyclic groups are those containing 3 to 7 ring atoms which includes at least one hetero atom, and includes cyclic amines such as morpholino, piperidino, pyrrolidino, and the like, and cyclic ethers/thio-ethers, such as tetrahydrofuran, tetrahydropyran, tetrahydrothiophene, and the like. Additionally, the heterocyclic group may be optionally substituted.

In some instances, the More Preferred General Substituents are selected from the group consisting of deuterium, fluorine, alkyl, cycloalkyl, alkoxy, aryloxy, amino, silyl, aryl, heteroaryl, sulfanyl, and combinations thereof.

In yet other instances, the Most Preferred General Substituents are selected from the group consisting of deuterium, fluorine, alkyl, cycloalkyl, aryl, heteroaryl, and combinations thereof.

The terms “substituted” and “substitution” refer to a substituent other than H that is bonded to the relevant position, e.g., a carbon or nitrogen. For example, when R1represents mono-substitution, then one R1must be other than H (i.e., a substitution). Similarly, when R1represents di-substitution, then two of R1must be other than H. Similarly, when R1represents zero or no substitution, R1, for example, can be a hydrogen for available valencies of ring atoms, as in carbon atoms for benzene and the nitrogen atom in pyrrole, or simply represents nothing for ring atoms with fully filled valencies, e.g., the nitrogen atom in pyridine. The maximum number of substitutions possible in a ring structure will depend on the total number of available valencies in the ring atoms.

In some instance, a pair of adjacent substituents can be optionally joined or fused into a ring. The preferred ring is a five, six, or seven-membered carbocyclic or heterocyclic ring, includes both instances where the portion of the ring formed by the pair of substituents is saturated and where the portion of the ring formed by the pair of substituents is unsaturated. As used herein, “adjacent” means that the two substituents involved can be on the same ring next to each other, or on two neighboring rings having the two closest available substitutable positions, such as 2, 2′ positions in a biphenyl, or 1, 8 position in a naphthalene, as long as they can form a stable fused ring system.

B. The OLED Devices of the Present Disclosure

In one aspect, the present disclosure provides an inventive organic light emitting device (OLED) comprising a first electrode and a second electrode with an organic layer stack between the electrodes; wherein the organic layer stack comprises an emissive layer (EML); and the EML comprises at least one emitter; and the ratio of the lifetime of the inventive OLED at 40° C. to the lifetime of an identical OLED at 20° C. is defined as ΔLT when each of the OLED and the identical OLED is run at the same current density (meaning the OLED is operated at the same current density); and wherein ΔLT is greater than 0.4.

It should be understood that “an identical OLED” refers to an OLED that is same as the inventive OLED in all respects, and the lifetime measurements are performed at the same current density. The only difference is that the lifetime of the inventive OLED is measured at 40° C., and the identical OLED is measured at 20° C. The lifetime of an OLED in this context is defined as the LT90 of the OLED. LT90 is defined as the time it takes for the OLED to lose 10% of its initial brightness at a given current density (mA/cm2). Thus, the ratio ΔLT=(LT90 of the inventive OLED measured at 40° C.)/(LT90 of an identical OLED measured at 20° C.).

As a specific example, if the inventive OLED is measured to have an LT90 of 10 hours at 20° C. with current density of 10 mA/cm2, and an identical OLED is measured to have an LT90 of 5 hours at 40° C. with current density of 10 mA/cm2, the ratio between the LT90 at 40° C. and the LT90 at 20° C. is 0.5. This ratio will be referred to herein as ΔLT. The OLED device having the ratio ΔLT of 0.5 ages twice as fast at 40° C. compared to 20° C. More generally, the terminology of ΔLT is used to describe the difference in the lifetime of an OLED at 40° C. compared to the lifetime of the OLED at 20° C. If this ratio ΔLT is 1.0, then there is no acceleration of the aging rate due to the elevated temperature, meaning that the lifetime of the OLED at 40° C. is the same as at 20° C. Thus, the closer the ratio ΔLT is to 1.0 the better. The closer the ratio ΔLT is to 1.0 the less the device ages at elevated temperatures. This means that under high current density when the device may heat up, the impact on aging from the increased temperature will be minimized. Furthermore, some applications require operation at elevated temperatures, say in a car that is outside on a sunny day. Increased longevity of the device at elevated temperatures will enable the device to be utilized in additional applications.

It should be understood that one of the objectives of the present disclosure is to minimize the impact of elevated temperature on the aging rate of an OLED, and it is believed increasing ΔLT can achieve that. In some embodiments, utilizing two hosts and one emitter in the blue OLED emissive layer (EML) may increase ΔLT. In other embodiments, alignment of the energy levels of the host with the emitter may increase ΔLT. In some embodiments, the emissive layer comprises a third host which may increase ΔLT. In some embodiments, modifying the rate at which either holes or electrons are transported through the emissive layer may increase ΔLT. In some embodiments, certain chemical structure of the host or emitter in the emissive layer may increase ΔLT. In some embodiments, modifying the hole injection barrier or electron injection barrier into the emissive layer may increase ΔLT. In some embodiments, modifying the rate at which either holes or electrons are transported through the hole transport layer (HTL) or electron transport layer (ETL), respectively, may increase ΔLT. In some embodiments, the work function of a material in the ETL may increase ΔLT.

In some embodiments, the emissive layer comprises two host compounds: a HH1 and an EH1. In some embodiments, either EH1 or HH1 has a spherocity less than to 0.32. In some embodiments, either EH1 or HH1 has a spherocity less than or equal to 0.25. In some embodiments, either EH1 or HH1 has a spherocity less than or equal to 0.20. In some embodiments both EH1 and HH1 have a spherocity less than 0.32. In some embodiments all of the hosts in the emissive layer have a spherocity less than 0.32. In some embodiments all of the hosts in the emissive layer have a spherocity less than 0.25.

The spherocity is a measurement of the three-dimensionality of bulky groups or hosts. Spherocity of a compound is defined as the ratio between the principal moments of inertia (PMI) of the compound. Specifically, spherocity of a compound is the ratio of three times PMI1 over the sum of PMI1, PMI2, and PMI3, where PMI1 is the smallest principal moment of inertia of the compound, PMI2 is the second smallest principal moment of inertia of the compound, and PMI3 is the largest principal moment of inertia of the compound. The spherocity of the lowest energy conformer of a structure after optimization of the ground state with density functional theory may be calculated. More detailed information can be found in paragraphs [0054] to [0059] of U.S. application Ser. No. 18/062,110 filed Dec. 6, 2022, the contents of which are incorporated herein by reference.

In some embodiments, the HH1 has a hole transport moiety and an absolute value of the HOMO energy of the HH1 is greater than 5.8 eV. In some embodiments, the absolute value of the HOMO energy of the HH1 is greater than 5.7 eV. In some embodiments, the absolute value of the HOMO energy of the HH1 is greater than 5.6 eV. In some embodiments, the absolute value of the HOMO energy of the HH1 is greater than 5.5 eV. In some embodiments, the absolute value of the HOMO energy of the HH1 is greater than 5.4 eV. In some embodiments, the absolute value of the HOMO energy of the HH1 is greater than 5.3 eV.

In some embodiments, the EH1 has an electron transport moiety and an absolute value of the LUMO energy of the EH1 is smaller than 2.8 eV. In some embodiments, the EH1 has an electron transport moiety and an absolute value of the LUMO energy of the EH1 is smaller than 2.7 eV. In some embodiments, the absolute value of the LUMO energy of the EH1 is smaller than 2.6 eV. In some embodiments, the absolute value of the LUMO energy of the EH1 is smaller than 2.4 eV. In some embodiments, the absolute value of the LUMO energy of the EH1 is smaller than 2.3 eV.

In some embodiments, the difference between the absolute HOMO energy of the HH1 and the absolute HOMO energy of the emitter ≤0.5 eV. In some embodiments, the difference between the absolute HOMO energy of the HH1 and the absolute HOMO energy of the emitter ≤0.4 eV. In some embodiments, the difference between the absolute HOMO energy of the HH1 and the absolute HOMO energy of the emitter ≤0.3 eV. In some embodiments, the difference between the absolute HOMO energy of the HH1 and the absolute HOMO energy of the emitter ≤0.2 eV. In some embodiments, the difference between the absolute HOMO energy of the HH1 and the absolute HOMO energy of the emitter ≤0.1 eV.

In some embodiments, the difference between the absolute LUMO energy of the EH1 and the absolute HOMO energy of the emitter ≤0.8 eV. In some embodiments, the difference between the absolute LUMO energy of the EH1 and the absolute HOMO energy of the emitter ≤0.7 eV. In some embodiments, the difference between the absolute LUMO energy of the EH1 and the absolute HOMO energy of the emitter ≤0.6 eV. In some embodiments, the difference between the absolute LUMO energy of the EH1 and the absolute HOMO energy of the emitter ≤0.5 eV. In some embodiments, the difference between the absolute LUMO energy of the EH1 and the absolute HOMO energy of the emitter ≤0.4 eV. In some embodiments, the difference between the absolute LUMO energy of the EH1 and the absolute HOMO energy of the emitter ≤0.3 eV.

It should be understood that the HOMO energy is estimated from the first oxidation potential derived from cyclic voltammetry. The LUMO energy is estimated from the first reduction potential derived from cyclic voltammetry. The triplet energy T1 of the emitter compounds is measured using the peak wavelength from the photoluminescence at 77K. Solution cyclic voltammetry and differential pulsed voltammetry were performed using a CH Instruments model 6201B potentiostat using anhydrous dimethylformamide solvent and tetrabutylammonium hexafluorophosphate as the supporting electrolyte. Glassy carbon, and platinum and silver wires were used as the working, counter and reference electrodes, respectively. Electrochemical potentials were referenced to an internal ferrocene-ferroconium redox couple (Fc+/Fc) by measuring the peak potential differences from differential pulsed voltammetry. The EHOMO=−[(Eox1vs Fc+/Fc)+4.8], and the ELUMO=−[(Ered1vs Fc+/Fc)+4.8], wherein Eox1is the first oxidation potential and the Ered1is the first reduction potential.

In some embodiments, the HH1 has a higher hole mobility than the electron mobility of the EH1 at room temperature (RT).

In some embodiments, the HH1 has a higher hole mobility than the electron mobility of the EH1 at 40° C.

In some embodiments, the HH1 has a higher hole mobility than the electron mobility of the EH1 at RT by more than one order of magnitude.

In some embodiments, the HH1 has a higher hole mobility than the electron mobility of the EH1 at RT at an electric field of 2×10{circumflex over ( )}6 V/cm2.

In some embodiments, the EH1 has a higher electron mobility than the hole mobility of the HH1 at RT.

In some embodiments, the EH1 has a higher electron mobility than the hole mobility of the HH1 at 40° C.

In some embodiments, the EH1 has a higher electron mobility than the hole mobility of the HH1 at RT by more than one order of magnitude.

In some embodiments, the EH1 has a higher electron mobility than the hole mobility of the HH1 at RT at an electric field of 2×10{circumflex over ( )}6 V/cm2.

In some embodiments, the concentrations of the HH1 and the EH1 in the EML are chosen such that the hole mobility in the EML matches the electron mobility in the EML at 40° C.

In some embodiments, the concentrations of the HH1 and the EH1 in the EML are chosen such that the hole mobility in the EML matches the electron mobility in the EML at RT.

It should be understood that the electron and hole mobilities for the OLED can be calculated by using Marcus Theory in which the charge reorganization energies are a leading factor. Marcus Theory is implemented in the materials modeling package Maestro version 21-3 developed by Schrödinger Inc. The calculation involves making an amorphous model of the host film than equilibrating that model with molecular dynamics to a reasonable density under standard conditions. Once a realistic model of the host film is obtained the electronic coupling constants for random pairs throughout the amorphous model are calculated. These electron coupling constants are used to calculate forward and backward charge transfer rates. With the charge transfer rates calculated Percolation Theory is used to find the most efficient pathway to transfer charge through the film from which the charge mobilities are elucidated.

In some embodiments, the concentrations of the HH1 and the EH1 in the EML are chosen such that the conductivity of holes and electrons in the EML is substantially similar at RT.

In some embodiments, the concentrations of the HH1 and the EH1 in the EML are chosen such that the conductivity of holes and electrons in the EML is substantially similar at 40° C.

One method to verify that the conductivity is similar is to fabricate and then measure the current voltage characteristics of “hole only” or “electron only” devices. “Hole only” or “electron only” devices are devices in which the electrodes, injection layers, and the other layers in the device are chosen such that only 1 charge carrier is injected and transported through the device when a voltage is applied. In properly constructed hole only or electron only devices there will be no injection barriers for charges so the voltage of the device directly reads on the conductivity of the most resistive element to that particular charge. For example, a hole only device may have the following layer structure: a hole injection layer, then a hole transporting layer, then an emissive layer (EML), then a hole transporting layer, and then a hole injection layer. In this device, the EML will have the least hole conductivity and the voltage of the device can be assumed to be only dependent on the hole conductivity through the EML. One can be more thorough, through studying the increases in voltage of the hole only device upon adding EML thickness. When doing this, the voltage will increase and the change in voltage is directly proportional to the conductivity of holes and independent of any injection barriers. Similar strategies can be applied to electron only devices. Additionally, these same measurements can be done on devices at elevated temperature, allowing for a comparison of the conductivity of holes and electrons through the EML at various temperatures.

In some embodiments, the EH1 comprises an atom selected from boron, silicon, oxygen, deuterium, and nitrogen.

In some embodiments, the HH1 comprises an atom selected from boron, silicon, oxygen, deuterium, and nitrogen.

In some embodiments, the emissive layer comprises a third host Host3.

In some embodiments, the Host3 has the deepest HOMO and shallowest LUMO in the EML.

In some embodiments, the Host3 comprises a silane, a tetraphenyl, or a carborane.

In some embodiments, the Host3 has a hole transport moiety and an absolute HOMO energy >5.7 eV.

In some embodiments, the Host3 has a hole transport moiety and an absolute HOMO energy >5.6 eV. In some embodiments, the Host3 has a hole transport moiety and an absolute HOMO energy >5.5 eV. In some embodiments, the Host3 has a hole transport moiety and an absolute HOMO energy >5.4 eV. In some embodiments, the Host3 has a hole transport moiety and an absolute HOMO energy >5.3 eV.

In some embodiments, the Host3 has an electron transport moiety and an absolute LUMO energy <2.8 eV. In some embodiments, the Host3 has an electron transport moiety and an absolute LUMO energy <2.7 eV.

In some embodiments, the Host3 has an electron transport moiety and an absolute LUMO energy <2.6 eV. In some embodiments, the Host3 has an electron transport moiety and an absolute LUMO energy <2.4 eV. In some embodiments, the Host3 has an electron transport moiety and an absolute LUMO energy <2.3 eV.

In some embodiments, the hole transporting moiety of the HH1 and the Host3 is selected from the group consisting of:

In some embodiments, the electron transporting moiety of the EH1 and the Host3 is selected from the group consisting of:

In some embodiments, the hosts in the EML have triplet energies greater than 2.88 eV. In some embodiments, the hosts in the EML have triplet energies greater than 2.50 eV.

In some embodiments, the EML emits blue light. In some of these embodiments, the blue light has an emission spectrum with a peak wavelength in the range of about 400-500 inn.

In some embodiments, the EML emits green light. In some of these embodiments, the green light has an emission spectrum with a peak wavelength in the range of about 500-600 nm.

In some embodiments, the organic layer stack comprises a hole blocking layer (HBL).

In some embodiments, the HBL is comprised of a material in the emissive layer.

In some embodiments, the HBL is not comprised of a material in the emissive layer.

In some embodiments, the electron mobility of the HBL is greater than that of the electron mobility of the EML at 40° C.

In some embodiments, the electron mobility of the HBL is greater than that of the electron mobility of the EML at RT.

In some embodiments, the LUMO level of the HBL is shallower than the deepest LUMO in the emissive layer.

In some embodiments, the LUMO level of the HBL is deeper than the deepest LUMO in the emissive layer.

In some embodiments, the organic layer stack comprises an electron blocking layer (EBL).

In some embodiments, the EBL is comprised of a material in the emissive layer.

In some embodiments, the EBL is not comprised of a material in the emissive layer.

In some embodiments, the hole mobility of the EBL is greater than that of the hole mobility of the EML at 40° C.

In some embodiments, the hole mobility of the EBL is greater than that of the electron mobility of the EML at RT.

In some embodiments, the organic layer stack comprises an electron transport layer (ETL).

In some embodiments, the ETL is comprised of a material in the emissive layer.

In some embodiments, the ETL is not comprised of a material in the emissive layer.

In some embodiments, the electron mobility of the ETL is greater than that of the electron mobility of the EML at 40° C.

In some embodiments, the electron mobility of the ETL is greater than that of the electron mobility of the EML at RT.

In some embodiments, the electron mobility of the ETL is smaller than that of the electron mobility of the EML at 40° C.

In some embodiments, the electron mobility of the ETL is smaller than that of the electron mobility of the EML at RT.

In some embodiments, the organic layer stack comprises a hole transport layer (HTL).

In some embodiments, the HTL is comprised of a material in the emissive layer.

In some embodiments, the HTL is not comprised of a material in the emissive layer.

In some embodiments, the hole mobility of the HTL is greater than that of the electron mobility of the HTL at 40° C.

In some embodiments, the hole mobility of the HTL is greater than that of the hole mobility of the EML at RT.

In some embodiments, the hole mobility of the HTL is smaller than that of the electron mobility of the HTL at 40° C.

In some embodiments, the hole mobility of the HTL is smaller than that of the hole mobility of the EML at RT.

In some embodiments, the ETL comprises a second compound. In some embodiments, the second compound has a work function 3.00 eV. In some embodiments, the second compound has a work function ≤2.90 eV. In some embodiments, the second compound has a work function 2.80 eV. In some embodiments, the second compound has a work function 2.70 eV. In some embodiments, the second compound has a work function ≤2.60 eV. In some embodiments, the second compound has a work function ≤2.50 eV.

In some embodiments, the emitter is selected from the list of: thermally activated delay fluorescent emitters, fluorescent emitters, phosphorescent emitters, doublet emitters, and emitters where the lowest energy excited state is a triplet exciton.

In some embodiments, the emitter contains a metal selected from Pt, Ir, Au, Ag, Rh, Pd, and Cu.

In some embodiments, the one of the electrodes is partially transmissive.

In some embodiments, the one of the electrodes is composed of Ag.

In some embodiments, an additional layer is disposed over the second electrode.

In some embodiments, the device converts energy from the plasmonic mode to light.

In some embodiments, the EML has a minimum thickness selected from the group consisting of 250, 300, 350, 400, 450, 500, 550, 600, 650 and 700 Å.

In some embodiments, the EML has a maximum thickness selected from the group consisting of 700, 750, 800, 850, 900, 950, and 1000 Å.

In some embodiments, each EML within the OLED emits only a single color.

As used herein, a “red” layer, material, region, or device refers to one that emits light in the range of about 580-700 nm; a “green” layer, material, region, or device refers to one that has an emission spectrum with a peak wavelength in the range of about 500-600 nm; a “blue” layer, material, or device refers to one that has an emission spectrum with a peak wavelength in the range of about 400-500 nm; and a “yellow” layer, material, region, or device refers to one that has an emission spectrum with a peak wavelength in the range of about 540-600 nm. In some arrangements, separate regions, layers, materials, regions, or devices may provide separate “deep blue” and a “light blue” light. As used herein, in arrangements that provide separate “light blue” and “deep blue”, the “deep blue” component refers to one having a peak emission wavelength that is at least about 4 nm less than the peak emission wavelength of the “light blue” component. Typically, a “light blue” component has a peak emission wavelength in the range of about 465-500 nm, and a “deep blue” component has a peak emission wavelength in the range of about 400-470 nm, though these ranges may vary for some configurations. Similarly, a color altering layer refers to a layer that converts or modifies another color of light to light having a wavelength as specified for that color. For example, a “red” color filter refers to a filter that results in light having a wavelength in the range of about 580-700 nm. In general, there are two classes of color altering layers: color filters that modify a spectrum by removing unwanted wavelengths of light, and color changing layers that convert photons of higher energy to lower energy. A component “of a color” refers to a component that, when activated or used, produces or otherwise emits light having a particular color as previously described. For example, a “first emissive region of a first color” and a “second emissive region of a second color different than the first color” describes two emissive regions that, when activated within a device, emit two different colors as previously described.

In some cases, it may be preferable to describe the color of a component such as an emissive region, sub-pixel, color altering layer, or the like, in terms of 1931 CIE coordinates. For example, a yellow emissive material may have multiple peak emission wavelengths, one in or near an edge of the “green” region, and one within or near an edge of the “red” region as previously described. Accordingly, as used herein, each color term also corresponds to a shape in the 1931 CIE coordinate color space. The shape in 1931 CIE color space is constructed by following the locus between two color points and any additional interior points.

Thus, for example, a “red” emissive region will emit light having CIE coordinates within the triangle formed by the vertices [0.6270,0.3725];[0.7347,0.2653]:[0.5086,0.2657]. Where the line between points [0.6270,0.3725] and [0.7347,0.2653] follows the locus of the 1931 color space. More complex color space regions can similarly be defined, such as the case with the green region. The color of the component is typically measured perpendicular to the substrate.

In some embodiments, the HH1 is at least 30% deuterated, at least 40% deuterated, at least 50% deuterated, at least 60% deuterated, at least 70% deuterated, at least 80% deuterated, at least 90% deuterated, at least 95% deuterated, at least 99% deuterated, or 100% deuterated.

In some embodiments, the EH1 is at least 30% deuterated, at least 40% deuterated, at least 50% deuterated, at least 60% deuterated, at least 70% deuterated, at least 80% deuterated, at least 90% deuterated, at least 95% deuterated, at least 99% deuterated, or 100% deuterated.

In some embodiments, the Host3 is at least 30% deuterated, at least 40% deuterated, at least 50% deuterated, at least 60% deuterated, at least 70% deuterated, at least 80% deuterated, at least 90% deuterated, at least 95% deuterated, at least 99% deuterated, or 100% deuterated.

In some embodiments, the ΔLT is greater than 0.7. In some embodiments, the ΔLT is greater than 0.8.

In another aspect, the present disclosure also provides a consumer product comprising an OLED as described herein. In some embodiments, the consumer product has two or more OLEDs and the two or more OLEDs all have a ΔLT that is greater than 0.4. In some embodiments, the consumer product has two or more OLEDs and the two or more OLEDs all have a ΔLT that is greater than 0.8. In some embodiments, the consumer product is one of a flat panel display, a computer monitor, a medical monitor, a television, a billboard, a light for interior or exterior illumination and/or signaling, a heads-up display, a fully or partially transparent display, a flexible display, a laser printer, a telephone, a cell phone, tablet, a phablet, a personal digital assistant (PDA), a wearable device, a laptop computer, a digital camera, a camcorder, a viewfinder, a micro-display that is less than 2 inches diagonal, a 3-D display, a virtual reality or augmented reality display, a vehicle, a video wall comprising multiple displays tiled together, a theater or stadium screen, a light therapy device, and a sign.

In some embodiments, the emissive layer further comprises an additional host, wherein the additional host comprises a triphenylene containing benzo-fused thiophene or benzo-fused furan;

wherein any substituent in the host is an unfused substituent independently selected from the group consisting of CnH2n+1, OCnH2n+1, OAr1, N(CnH2n+1)2, N(Ar1)(Ar2), CH═CH—CnH2n+1, C≡CCnH2n+1, Ar1, Ar1-Ar2, CnH2n—Ar1, or no substitution;
wherein n is from 1 to 10; and wherein Ar1and Ar2are independently selected from the group consisting of benzene, biphenyl, naphthalene, triphenylene, carbazole, and heteroaromatic analogs thereof.

In some embodiments, the emissive layer further comprises an additional host, wherein the additional host comprises at least one chemical moiety selected from the group consisting of triphenylene, carbazole, indolocarbazole, dibenzothiphene, dibenzofuran, dibenzoselenophene, 5,9-dioxa-13b-boranaphtho[3,2,1-de]anthracene, aza-triphenylene, aza-carbazole, aza-indolocarbazole, aza-dibenzothiophene, aza-dibenzofuran, aza-dibenzoselenophene, and aza-(5,9-dioxa-13b-boranaphtho[3,2,1-de]anthracene).

In some embodiments, the emissive layer further comprises an additional host, and the additional host can be selected from the group consisting of the compounds in the following HOST group 1:

each of X1to X24is independently C or N;

L′ is a direct bond or an organic linker;

each of RA′, RB′, RC′, RD′, RE′, RF′, and RG′independently represents mono, up to the maximum substitutions, or no substitutions;

two adjacent of RA′, RB′, RC′, RD′, RE′, RF′, and RG′are optionally joined or fused to form a ring.

In some embodiments, the additional host can be selected from the group consisting of the structures in the following HOST group 2:

and combinations thereof.

In some embodiments, the emissive layer can further comprise a host, wherein the host comprises a metal complex.

In some embodiments, at least one of the anode, the cathode, or a new layer disposed over the organic emissive layer functions as an enhancement layer. The enhancement layer comprises a plasmonic material exhibiting surface plasmon resonance that non-radiatively couples to the emitter material and transfers excited state energy from the emitter material to non-radiative mode of surface plasmon polariton. The enhancement layer is provided no more than a threshold distance away from the organic emissive layer, wherein the emitter material has a total non-radiative decay rate constant and a total radiative decay rate constant due to the presence of the enhancement layer and the threshold distance is where the total non-radiative decay rate constant is equal to the total radiative decay rate constant. In some embodiments, the OLED further comprises an outcoupling layer. In some embodiments, the outcoupling layer is disposed over the enhancement layer on the opposite side of the organic emissive layer. In some embodiments, the outcoupling layer is disposed on opposite side of the emissive layer from the enhancement layer but still outcouples energy from the surface plasmon mode of the enhancement layer. The outcoupling layer scatters the energy from the surface plasmon polaritons. In some embodiments this energy is scattered as photons to free space. In other embodiments, the energy is scattered from the surface plasmon mode into other modes of the device such as but not limited to the organic waveguide mode, the substrate mode, or another waveguiding mode. If energy is scattered to the non-free space mode of the OLED other outcoupling schemes could be incorporated to extract that energy to free space. In some embodiments, one or more intervening layer can be disposed between the enhancement layer and the outcoupling layer. The examples for interventing layer(s) can be dielectric materials, including organic, inorganic, perovskites, oxides, and may include stacks and/or mixtures of these materials.

The enhancement layer modifies the effective properties of the medium in which the emitter material resides resulting in any or all of the following: a decreased rate of emission, a modification of emission line-shape, a change in emission intensity with angle, a change in the stability of the emitter material, a change in the efficiency of the OLED, and reduced efficiency roll-off of the OLED device. Placement of the enhancement layer on the cathode side, anode side, or on both sides results in OLED devices which take advantage of any of the above-mentioned effects. In addition to the specific functional layers mentioned herein and illustrated in the various OLED examples shown in the figures, the OLEDs according to the present disclosure may include any of the other functional layers often found in OLEDs.

The enhancement layer can be comprised of plasmonic materials, optically active metamaterials, or hyperbolic metamaterials. As used herein, a plasmonic material is a material in which the real part of the dielectric constant crosses zero in the visible or ultraviolet region of the electromagnetic spectrum. In some embodiments, the plasmonic material includes at least one metal. In such embodiments the metal may include at least one of Ag, Al, Au, Ir, Pt, Ni, Cu, W, Ta, Fe, Cr, Mg, Ga, Rh, Ti, Ru, Pd, In, Bi, Ca alloys or mixtures of these materials, and stacks of these materials. In general, a metamaterial is a medium composed of different materials where the medium as a whole acts differently than the sum of its material parts. In particular, we define optically active metamaterials as materials which have both negative permittivity and negative permeability. Hyperbolic metamaterials, on the other hand, are anisotropic media in which the permittivity or permeability are of different sign for different spatial directions. Optically active metamaterials and hyperbolic metamaterials are strictly distinguished from many other photonic structures such as Distributed Bragg Reflectors (“DBRs”) in that the medium should appear uniform in the direction of propagation on the length scale of the wavelength of light. Using terminology that one skilled in the art can understand: the dielectric constant of the metamaterials in the direction of propagation can be described with the effective medium approximation. Plasmonic materials and metamaterials provide methods for controlling the propagation of light that can enhance OLED performance in a number of ways.

In some embodiments, the enhancement layer is provided as a planar layer. In other embodiments, the enhancement layer has wavelength-sized features that are arranged periodically, quasi-periodically, or randomly, or sub-wavelength-sized features that are arranged periodically, quasi-periodically, or randomly. In some embodiments, the wavelength-sized features and the sub-wavelength-sized features have sharp edges.

In some embodiments, the outcoupling layer has wavelength-sized features that are arranged periodically, quasi-periodically, or randomly, or sub-wavelength-sized features that are arranged periodically, quasi-periodically, or randomly. In some embodiments, the outcoupling layer may be composed of a plurality of nanoparticles and in other embodiments the outcoupling layer is composed of a plurality of nanoparticles disposed over a material. In these embodiments the outcoupling may be tunable by at least one of varying a size of the plurality of nanoparticles, varying a shape of the plurality of nanoparticles, changing a material of the plurality of nanoparticles, adjusting a thickness of the material, changing the refractive index of the material or an additional layer disposed on the plurality of nanoparticles, varying a thickness of the enhancement layer, and/or varying the material of the enhancement layer. The plurality of nanoparticles of the device may be formed from at least one of metal, dielectric material, semiconductor materials, an alloy of metal, a mixture of dielectric materials, a stack or layering of one or more materials, and/or a core of one type of material and that is coated with a shell of a different type of material. In some embodiments, the outcoupling layer is composed of at least metal nanoparticles wherein the metal is selected from the group consisting of Ag, Al, Au, Ir, Pt, Ni, Cu, W, Ta, Fe, Cr, Mg, Ga, Rh, Ti, Ru, Pd, In, Bi, Ca, alloys or mixtures of these materials, and stacks of these materials. The plurality of nanoparticles may have additional layer disposed over them. In some embodiments, the polarization of the emission can be tuned using the outcoupling layer. Varying the dimensionality and periodicity of the outcoupling layer can select a type of polarization that is preferentially outcoupled to air. In some embodiments the outcoupling layer also acts as an electrode of the device.

In yet another aspect, the present disclosure also provides a consumer product comprising an organic light-emitting device (OLED) as described herein.

In some embodiments, the consumer product can be one of a flat panel display, a computer monitor, a medical monitor, a television, a billboard, a light for interior or exterior illumination and/or signaling, a heads-up display, a fully or partially transparent display, a flexible display, a laser printer, a telephone, a cell phone, tablet, a phablet, a personal digital assistant (PDA), a wearable device, a laptop computer, a digital camera, a camcorder, a viewfinder, a micro-display that is less than 2 inches diagonal, a 3-D display, a virtual reality or augmented reality display, a vehicle, a video wall comprising multiple displays tiled together, a theater or stadium screen, a light therapy device, and a sign.

Several OLED materials and configurations are described in U.S. Pat. Nos. 5,844,363, 6,303,238, and 5,707,745, which are incorporated herein by reference in their entirety.

C. The OLED Devices of the Present Disclosure with Other Materials

The organic light emitting device of the present disclosure may be used in combination with a wide variety of other materials. For example, it may be used in conjunction with a wide variety of hosts, transport layers, blocking layers, injection layers, electrodes and other layers that may be present. The materials described or referred to below are non-limiting examples of materials that may be useful in combination with the device disclosed herein, and one of skill in the art can readily consult the literature to identify other materials that may be useful in combination.

wherein Met is a metal, which can have an atomic weight greater than 40; (Y101-Y102) is a bidentate ligand, Y101and Y102are independently selected from C, N, O, P, and S; L101is an ancillary ligand; k′ is an integer value from 1 to the maximum number of ligands that may be attached to the metal; and k+k″ is the maximum number of ligands that may be attached to the metal.

In one aspect, the metal complexes are:

wherein k is an integer from 1 to 20; L101is another ligand, k′ is an integer from 1 to 3.

D. Experimental Section

A number of blue PHOLED emitters and host combinations were made and tested. Materials that were in the OLEDs are the following:

OLEDs were grown on a glass substrate pre-coated with an indium-tin-oxide (ITO) layer having a sheet resistance of 15-Ω/sq. Prior to any organic layer deposition or coating, the substrate was degreased with solvents and then treated with an oxygen plasma for 1.5 minutes with 50 W at 100 mTorr and with UV ozone for 5 minutes.

Various combinations of material device were fabricated and the ΔLTs were measured. It was found that the ΔLT spanned the range from 0.27 to 0.62 for the devices made. More generally, ΔLT could span from 0 to 1. the ΔLT was measured in an effort to understand the robustness of the metric of ΔLT using the same EML composition but at various driving current densities during lifetest. This data is summarized in Table 1. It was found that the ΔLT was not modified within the range of 3-30 mA/cm2of initial driving current density for these blue PHOLED emitters.

The devices in Tables 1 were fabricated in high vacuum (<10−7Torr) by thermal evaporation. The anode electrode was 750 Å of indium tin oxide (ITO). The device example had organic layers consisting of, sequentially, from the ITO surface, 100 Å of Compound 1 (HIL), 250 Å of Compound 2 (HTL), 50 Å of HH2 (EBL), 300 Å of HH2 doped with 60% of EH6 and 12% of BD1 (EML), 50 Å of EH6 (BL), 300 Å of Compound 4 doped with 35% of Compound 5 (ETL), 10 Å of Compound 4 (EIL) followed by 1,000 Å of Al (Cathode). All devices were encapsulated with a glass lid sealed with an epoxy resin in a nitrogen glove box (<1 ppm of H2O and O2) immediately after fabrication with a moisture getter incorporated inside the package. Doping percentages are in volume percent. The ΔLT was then measured for a number of different host combinations with emitter BD1. These results are summarized in Table 2.

The devices in Table 2 were fabricated in high vacuum (<10−7Torr) by thermal evaporation. The anode electrode was 750 Å of indium tin oxide (ITO). The device example had organic layers consisting of, sequentially, from the ITO surface, 100 Å of Compound 1 (HIL), 250 Å of Compound 2 (HTL), 50 Å of one of HH1-HH8 as noted in the table (EBL), 300 Å of one of HH1-HH8 doped with a percentage of one of EH1-EH6 and 12% of BD1 (EMIL), 50 Å of one of EHosts EH1-EH6 as noted in the table (BL), 300 Å of Compound 3 doped with 35% of Compound 4 (ETL), 10 Å of Compound 3 (EIL) followed by 1,000 Å of Al (Cathode). All devices were encapsulated with a glass lid sealed with an epoxy resin in a nitrogen glove box (<1 ppm of H2O and O2) immediately after fabrication with a moisture getter incorporated inside the package. Doping percentages are in volume percent.

It was found that the ratio ΔLT was larger for some host systems than others. In particular, some host combinations enabled the ability to have a ΔLT greater than 0.4. Each hole transporting host could generate a ΔLT above 0.4 although HH1 only had 1 of 4 combinations of hosts that had a ΔLT>0.4 while HH7 and HH5 had a ΔLT>0.4 2 of 2 times each. For electron transporting hosts only EH1, EH2, EH4, and EH5 had a ΔLT>0.4 in host combinations. For EH2 only 1 of 4 combinations had a ΔLT>0.4 while EH1 achieved a ΔLT>0.4 for 5 of 5 combinations. Without being bound by any specific theory, it is believed that the shape of the molecule played a role in the determination of ΔLT. We find that if the emissive layer is composed of two hosts each with a spherocity below that of 0.32 that the ΔLT is above 0.4 for the emissive layer when using BD1. As the spherocity is lowered, the host becomes more one dimensional, this may enable the host molecules to pack more tightly together and lower the sensitivity of the device aging to increased temperature by limiting the degrees of freedom explore upon increasing temperature.