ORGANIC ELECTROLUMINESCENT DEVICE WITH DELAYED FLUORESCENCE

Abstract

A first device comprising a first organic light emitting device, further comprising: an anode, a cathode and an emitting layer arranged between the anode and the cathode and a first emitting dopant, wherein the first emitting dopant is organic and does not contain any metal, wherein the first emitting dopant comprises an electron donor and an electron acceptor moiety, wherein the first emissive dopant has a calculated HOMO energy higher than or equal to -4.70 eV, wherein the first emissive dopant has a calculated LUMO energy greater than or equal to -1.20 eV, and wherein the first emitting dopant has an energy ratio determined by dividing the T1 energy of the first emitting dopant by ΔE HOMO-LUMOis calculated for the first emitting dopant, where the energy ratio is at least 0.70, wherein the first emitting dopant has an energy difference determined by subtracting the T1 energy of the first emitting dopant from ΔE HOMO-LUMO is calculated for the first emitting dopant, where the energy difference is less than or equal to 1.00 eV, and where the first emitting dopant has the formula: has, wherein A represents an aromatic carbocyclic or heterocyclic radical having at least two fused carbocyclic or heterocyclic rings, where ring P is an aromatic carbocyclic or heterocyclic ring, where Ar 1 , Ar 2 and Ar 3 aryl or heteroaryl and are optionally further substituted, where the ring A, Ar 1 , Ar 2and Ar 3 may be fused, where R 1 represents a mono-, di-, tri- or tetrasubstitution or no substitution, where R 1 is selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, esters, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof, and where n is 2.

Description

The present invention relates to organic compounds having strong electron donating properties and weak electron accepting properties within the same molecule. These compounds exhibit delayed fluorescence properties when incorporated into OLED devices.Optoelectronic devices utilizing organic materials are becoming increasingly desirable for a number of reasons. Many of the materials used to fabricate such devices are relatively inexpensive, so organic optoelectronic devices have a potential for cost advantages over inorganic devices. Moreover, the inherent properties of organic materials, such as their flexibility, can make them well suited for certain applications, such as fabrication on a flexible substrate. Examples of organic optoelectronic devices include organic light emitting devices (OLEDs), organic phototransistors, organic solar cells, and organic photodetectors. For OLEDs, the organic materials may have performance advantages over conventional materials. For example, the wavelength at which an organic emitting layer emits light could generally be easily adjusted with suitable dopants.OLEDs use thin organic films that emit light when a voltage is applied to the device. OLEDs become an increasingly interesting technology for use in applications such as flat panel displays, lighting and backlighting. Some OLED materials and configurations are described in U.S. Patents US 5,844,363 A, US 6 303 238 B1 and US 5 707 745 A.One application for phosphorescent emitting molecules is a color display. Industry standards for such display require pixels that are adapted to emit certain colors, referred to as "saturated" colors. In particular, these standards require saturated red, green and blue pixels. Color can be measured using CIE coordinates well known in the art.An example of a green emitting molecule is tris(2-phenylpyridine)iridium, referred to as Ir(ppy) 3 and having the following structure: In this and the figures shown later herein, the coordinative bond of nitrogen to a metal (here Ir) is shown as a straight line.As used herein, the term "organic" encompasses polymeric materials as well as small molecule organic materials that can be used to make organic optoelectronic devices. "small molecule" refers to any organic material that is not a polymer, and "small molecules" can in fact be quite large. Small molecules may in some cases comprise repeat units. For example, the use of a long chain alkyl group as a substituent does not result in a molecule not belonging to the class of a "small molecule". Small molecules may also be included in polymers, for example as a pendant group on a polymer backbone or as part of the backbone. Small molecules can also serve as the core unit of a dendrimer consisting of a series of chemical shells disposed around the core unit. The core unit of a dendrimer may be a small fluorescent or phosphorescent molecular emission source. A dendrimer may be a "small molecule" and all dendrimers currently used in the field of OLEDs are believed to be small molecules.As used herein, "top" means furthest from the substrate, while "bottom" means closest to the substrate. Where a first layer is described as being "disposed over" a second layer, the first layer is disposed further from the substrate. Additional layers may be present between the first and second layers unless the first layer is indicated as "in contact with" the second layer. For example, a cathode may be described as being "disposed over" an anode, even though there are various organic layers therebetween.As used herein, "solution processable" means being soluble in a liquid medium, dispersible or transportable to and / or disintegratable from a liquid medium, either in solution or suspension form.A ligand may be referred to as "photoactive" when it is believed that the ligand contributes directly to the photoactive properties of an emitting material. A ligand may be referred to as "complementary" if it is believed that the ligand does not contribute to the photoactive properties of an emitting material, although a complementary ligand could alter the properties of a photoactive ligand.As used herein, and as generally understood by those of ordinary skill in the art, a first "highest occupied molecular orbital" (HOMO) or "lowest unoccupied molecular orbital" (LUMO) energy level is "greater than" or "higher than" a second HOMO or LUMO energy level when the first energy level is closer to the vacuum energy level. Since ionization potentials (IP) are measured as negative energy with respect to the vacuum level, a higher HOMO energy level corresponds to an IP having a smaller absolute value (an IP being less negative). Similarly, a higher LUMO energy level corresponds to an electron affinity (EA) having a smaller absolute value (an EA that is less negative). In a conventional energy level diagram, where the vacuum level is at the top, the LUMO energy level of a material is higher than the HOMO energy level of the same material. A "higher" HOMO or LUMO energy level appears closer to the top of such a plot than a "lower" HOMO or LUMO energy level.As used herein, and as generally understood by those of ordinary skill in the art, a first exit energy is "greater than" or "greater than" a second exit energy when the first exit energy has a higher absolute value. Because output energies are generally measured as negative numbers relative to the vacuum level, this means that a "higher" output energy is more negative. In a conventional energy level diagram, with the vacuum level at the top, a "higher" exit energy is depicted further away from the vacuum level in the downward direction. Thus, for the definitions of HOMO and LUMO energy levels, a different convention applies than for exit energies.Further details of OLEDs and the definitions described above are given in U.S. Pat. No. 7,279,704 B2. Further prior art can be found in US 2010 / 314 615 A1, US 2012 / 0 319 091 A1, and WO 2011 / 090 149 A1.A first device is provided. The first device comprises a first organic light emitting device further comprising an anode, a cathode, and an emitting layer disposed between the anode and the cathode and comprising a first emitting dopant. The first emissive dopant is organic and does not contain a metal and comprises an electrode donor moiety and an electron acceptor moiety. The first emissive dopant has a calculated HOMO energy that is greater than or equal to -4.70 eV and a calculated LUMO energy that is greater than or equal to -1.20 eV. The first emissive dopant has an energy ratio calculated by dividing the T1 energy of the first emissive dopant by ΔE HOMO-LUMO for the first emissive dopant, wherein the energy ratio is at least 0.70. The first emitting dopant also has an energy difference calculated by subtracting the T1 energy of the first emitting dopant from ΔE HOMO-LUMO for the first emitting dopant, wherein the energy difference is less than or equal to 1.00 eV. The first emitting dopant has the following formula I: In the compound of formula I, A represents an aromatic carbocyclic or heterocyclic radical having at least two fused carbocyclic or heterocyclic rings and ring P is an aromatic carbocyclic or heterocyclic ring. Ar 1, Ar 2 and Ar 3 are aryl or heteroaryl and are optionally further substituted. Rings A, Ar 1, Ar 2 and Ar 3 are optionally fused. R 1 represents a mono, di, tri or tetra substitution or no substitution. R 1 is selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof, and n is 2.In one aspect, the energy difference is less than or equal to 0.90 eV.In one aspect, the energy ratio is at least 0.73 and the energy difference is less than or equal to 0.90 eV.In one aspect, the energy ratio is at least 0.73.In one aspect, A has the formula: or wherein X is O, S or Se, Z 1 to Z 8 independently comprise C or N, and the total number of N in Z 1 to Z 8 is at most 1. R is selected from the group consisting of alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof. R 2 represents a mono-, di-, tri- or tetrasubstitution or no substitution, R 3 represents a mono-, di- or trisubstitution or no substitution, and R 4 represents a mono-, di-, tri- or tetrasubstitution or no substitution. R 2, R 3 and R 4 are independently selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof.In one aspect, the first emissive dopant has the formula: In one aspect, Ar 1, Ar 2 and Ar 3 are independently selected from the group consisting of phenyl and triphenylene.In one aspect, the ring P, Ar 1, Ar 2 and Ar 3 are phenyl. In one aspect, X is NR wherein R is aryl or heteroaryl. In one aspect, X is O. In one aspect, X is S.In one aspect, the first emissive dopant is selected from the group consisting of: , and A further first device is provided. The first device comprises a first organic light emitting device further comprising an anode, a cathode, and an emitting layer disposed between the anode and the cathode and comprising a first emitting dopant. The first emissive dopant is organic and does not contain a metal and comprises an electrode donor moiety and an electron acceptor moiety. The first emissive dopant has a calculated HOMO energy that is greater than or equal to -4.70 eV and a calculated LUMO energy that is greater than or equal to -1.20 eV. The first emissive dopant has an energy ratio calculated by dividing the T1 energy of the first emissive dopant by ΔE HOMO-LUMO for the first emissive dopant, wherein the energy ratio is at least 0.70. The first emitting dopant also has an energy difference calculated by subtracting the T1 energy of the first emitting dopant from ΔE HOMO-LUMO for the first emitting dopant, wherein the energy difference is less than or equal to 1.00 eV. The first emissive dopant is selected from the group consisting of: and In one aspect, the first device emits a luminescent radiation at room temperature when a voltage is applied to the organic light emitting device, wherein the luminescent radiation comprises a delayed fluorescence process.In one aspect, ring A, Ar 1, Ar 2 or A 3 are fused so that at least one carbazole moiety is formed.A further first device is provided. The first device comprises a first organic light emitting device further comprising an anode, a cathode, and an emitting layer disposed between the anode and the cathode and comprising a first emitting dopant. The first emissive dopant is organic and does not contain a metal and comprises an electrode donor moiety and an electron acceptor moiety. The first emissive dopant has a calculated HOMO energy that is greater than or equal to -4.70 eV and a calculated LUMO energy that is greater than or equal to -1.20 eV. The first emissive dopant has an energy ratio calculated by dividing the T1 energy of the first emissive dopant by ΔE HOMO-LUMO for the first emissive dopant, wherein the energy ratio is at least 0.70. The first emitting dopant also has an energy difference calculated by subtracting the T1 energy of the first emitting dopant from ΔE HOMO-LUMO for the first emitting dopant, wherein the energy difference is less than or equal to 1.00 eV. The first emissive dopant is selected from the group consisting of: In one aspect, the emitting layer further comprises a first phosphorescence emitting material.In one aspect, the emitting layer further comprises a second phosphorescence emitting material.In one aspect, the first emitting dopant emits white light at room temperature when a voltage is applied to the organic light emitting device.In one aspect, the first emissive dopant emits blue light having a peak wavelength between about 400 nm to about 500 nm.In one aspect, the first emitting dopant emits yellow light having a peak wavelength between about 530 nm to about 580 nm.In one aspect, the first device includes a second organic light emitting device, wherein the second organic light emitting device is stacked on the first organic light emitting device.In one aspect, the first device is a consumer product. In one aspect, the first device is an organic light emitting device. In one aspect, the first device comprises an illumination unit.FIG. 1 shows an organic light emitting device.FIG. 2 shows an inverted organic light emitting device that does not have a separate electron transport layer.Figure 3 shows a compound of formula I.FIG. 4 shows the emission spectrum of compound 1 in 2-methyltetrahydrofuran at room temperature and 77 K.FIG. 5 shows the emission spectrum of compound 2 in 2-methyltetrahydrofuran at room temperature and 77 K.Figure 6 shows the effect of solvent on the room temperature emission spectrum of compound 1.Figure 7 shows the effect of solvent on the room temperature emission spectrum of compound 2.Generally, an OLED comprises at least one organic layer disposed between and electrically connected to an anode and a cathode. When a current is applied, the anode injects holes and the cathode injects electrons into the organic layer(s). The injected holes and electrons each migrate to the oppositely charged electrode. When an electron and a hole are on the same molecule, an "exciton" is formed which is a localized electron-hole pair having an excited energy state. Light is emitted when the exciton relaxes by a light emission mechanism. In some cases, the exciton may be localized to an excimer or an exciplex. Nonradiative mechanisms such as thermal relaxation may also occur, but are generally not desirable.The first OLEDs used emitting molecules that emitted light from their singlet states ("fluorescence"), as disclosed, for example, in U.S. Patent 4,769,292 A. Fluorescence emission generally occurs in a time frame of less than 10 nanoseconds.Recently, OLEDs have been presented which comprise emitting materials which emit light from triplet states ("phosphorescence"). Baldo et al., "Highly Efficient Phosphor Emission from Organic Electroluminescent Devices", Nature, Vol. 395, 151-154, 1998 ("Baldo-I") and Baldo et al., "Very high-efficiency green organic light-emitting devices based on electrophosphorescence", Appl. Phys. Lett., Vol. 75, No. 3, 4-6 (1999) ("Baldo-II"), which are incorporated herein by reference in their entirety. Phosphorescence is described in more detail in U.S. Pat. No. 7,279,704 B2 in columns 5-6.FIG. 1 shows an organic light emitting device 100. The figures are 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, an emitting layer 135, a hole blocking layer 140, an electron transport layer 145, an electron injection layer 150, a protection layer 155, a cathode 160, and a blocking layer 170. The cathode 160 is a composite cathode that includes a first conductive layer 162 and a second conductive layer 164. The device 100 may be manufactured by depositing the described layers one after the other. The properties and functions of these various layers and example materials are described in more detail in U.S. Pat. No. 7,279,704 B2 in columns 6-10.There are further examples of each of these layers. For example, a flexible and transparent substrate-anode combination is described in U.S. Patent No. US 5 844 363 A 5. An example of a p-doped hole transport layer is m-MTDATA doped with F 4- TCNQ in a molar ratio of 50:1, as disclosed in U.S. patent application US 2003 / 0 230 980 A1. Examples of emissive materials and host materials are disclosed in U.S. Patent No. 6,303,238 B1 to Thompson et al. An example of an n-doped electron transport layer is BPhen which is doped with Li in a molar ratio of 1:1, as disclosed in U.S. patent application US 2003 / 0 230 980 A1. U.S. Patents 5,703,436 A and 5,707,745 A disclose examples of cathodes, including composite cathodes having a thin layer of metal, such as Mg:Ag, with an overlying transparent electrically conductive sputter deposited ITO layer. The theory and use of barrier layers is described in more detail in U.S. Pat. No. 6,097,147 A and in U.S. Pat. No. 2003 / 0 230 980 A1. Examples of injection layers are given in U.S. patent application US 2004 / 0 174 116 A1. A description of protective layers can be found in U.S. patent application US 2004 / 0 174 116 A1.FIG. 2 shows an inverted OLED 200. The device includes a substrate 210, a cathode 215, an emitting layer 220, a hole transport layer 225, and an anode 230. The device 200 may be manufactured by depositing the described layers one after the other. Because in the most common OLED configuration, a cathode is disposed over the anode and in device 200, cathode 215 is disposed under anode 230, device 200 may be referred to as an "inverted" OLED. Materials similar to those described with respect to device 100 may be used in the respective layers of device 200. FIG. 2 shows an example of how some layers may be omitted from the structure of the device 100.The simple layered structure shown in Figures 1 and 2 is given as a non-limiting example and it is understood that embodiments of the invention may be used in conjunction with a wide variety of other structures. The specific materials and structures described are exemplary in nature and other materials and structures may be used. Functional OLEDs can be obtained by combining the described different layers in different ways or layers can be completely omitted due to design, performance and cost factors. Other layers not specifically described may also be included. Materials other than those specifically described may be used. Although many of the examples provided herein describe different layers as containing a single material, it should be understood that combinations of materials, such as a mixture of host material and dopant, or more generally a mixture, may be used. The layers may also have different sub-layers. The terms given to the various layers herein are not intended to be strictly limited. For example, in device 200, hole transport layer 225 transports holes and injects holes into emitting layer 220, and may be described as a hole transport layer or a hole injection layer. In one embodiment, an OLED may be described as having an "organic layer" disposed between a cathode and an anode. This organic layer may comprise a single layer or may further comprise multiple layers of different organic materials, as described for example with reference to FIGS. 1 and 2.Structures and materials not specifically described may also be used, such as OLEDs comprising polymeric materials (PLEDs) as disclosed in U.S. Patent No. 5,247,190 to Friend et al. As another example, OLEDs having a single organic layer may be used. OLEDs can be stacked as described, for example, in U.S. Patent No. 5,707,745 to Forrest et al. The OLED structure may deviate from the simple layer structure as illustrated in FIGS. 1 and 2. The substrate may include, for example, an angled reflective surface to improve decoupling, such as a mesa structure as described in U.S. Pat. No. 6,091,195 to Forrest et al. and / or a well structure as described in U.S. Pat. No. 5,834,893 to Bulovic et al.Unless otherwise indicated, any of the layers of the various embodiments may be deposited by any suitable method. Preferred methods for the organic layers include thermal evaporation, inkjet as described in U.S. Pat. Nos. 6,013,982 A and 6,087,196 A, organic vapor deposition (OVPD) as described in U.S. Pat. No. 6,337,102 B1 to Forrest et al., and organic vapor jet printing (OVJP) deposition as described in U.S. Pat. No. 7,431,968 B1. Other suitable deposition methods include spin coating and other solution-based methods. Solution-based processes are preferably carried out in nitrogen or an inert atmosphere. Preferred methods for the other layers include thermal evaporation. Preferred patterning techniques include mask deposition, cold welding as described in U.S. Pat. Nos. 6,294,398 B1 and 6,468,819 B1, and patterning associated with some of the deposition techniques such as inkjet and OVJD. Other methods may also be used. The materials to be deposited may be modified to make them compatible with a particular deposition process. For example, substituents such as alkyl and aryl groups, which are branched or unbranched and which preferably contain at least three carbon atoms, may be used in small molecules to improve their ability to be processed in solution. Substituents having 20 carbon atoms or more may be used, and a preferable range is 3-20 carbon atoms. Materials with asymmetric structures may have better solution processability than those with symmetric structures because asymmetric materials may have less tendency to recrystallized. Dendrimer substituents can be used to improve the ability of the small molecules to be processed in solution.Devices fabricated according to embodiments of the present invention may optionally further comprise a barrier layer. A purpose of the barrier layer is to protect the electrodes and organic layers from damaging exposure to harmful species in the environment, including moisture, vapor and / or gases, etc. The barrier layer may be deposited over, under, or adjacent to a substrate, electrode, or over any other parts of a device including an edge. The barrier layer may comprise a single layer or multiple layers. The barrier layer may be formed by various known chemical vapor deposition techniques and may include compositions having a single phase as well as compositions having multiple phases. Any suitable material or combination of materials may be used for the barrier layer. The barrier layer may contain an inorganic or organic compound or both. The preferred barrier layer comprises a mixture of a polymeric material and a non-polymeric material as described in U.S. Pat. No. 7,968,146 B2, PCT patent applications WO 2008 / 057 394 A1 and WO 2010 / 011 390 A2. To be considered a "mixture", the said polymeric and non-polymeric materials forming the barrier layer should be deposited under the same reaction conditions and / or at the same time. The weight ratio of polymeric to non-polymeric material may range from 95:5 to 5:95. The polymeric material and the non-polymeric material may be formed from the same starting material. In one example, the mixture of a polymeric material and a non-polymeric material consists essentially of polymeric silicon and inorganic silicon.Devices made according to embodiments of the invention may be incorporated into a wide variety of consumer goods, including flat panel displays, computer monitors, medical monitors, televisions, advertising panels, lights for interior or exterior lighting and / or signalling, head-up displays, fully transparent displays, flexible displays, laser printers, telephones, cell phones, personal digital assistants (PDAs), laptop computers, digital cameras, camcorders, viewfinders, microdisplays, vehicles, a large wall surface, a theater or standion screen, or a sign. Various control mechanisms may be used to control the devices fabricated according to the present invention, including passive matrix and active matrix. Many of the devices are intended for use in a human-comfortable temperature range, such as 18°C to 30°C, and more preferably at room temperature (20-25°C).The materials and structures described herein may be used in devices other than OLEDs. For example, the materials and structures may be used in other optoelectronic devices, such as organic solar cells and organic photodetectors. More generally, the materials and structures may be used in organic devices, such as organic transistors.The terms halo, halo, alkyl, cycloalkyl, alkenyl, alkynyl, aralkyl, heterocyclic group, aryl, aromatic group, and heteroaryl are known in the art and are defined in U.S. Pat. No. 7,279,704 B2 at columns 31-32.It is believed that the internal quantum efficiency (IQE) of fluorescent OLEDs can exceed the 25% spin statistical limit by delayed fluorescence. As used herein, there are two types of delayed fluorescence, i.e., P-type delayed fluorescence and E-type delayed fluorescence. P-type delayed fluorescence is generated by triplet-triplet quenching (TTA).On the other hand, E-type delayed fluorescence is not due to the collision of two triplets, but rather due to the thermal population between the triplet states and the excited singlet states. Compounds capable of producing E-type delayed fluorescence must have very small singlet-triplet spacings. Thermal energy can activate the transition from the triplet state back to the singlet state. This type of delayed fluorescence is also known as thermally activated delayed fluorescence (TADF). A characteristic feature of a TADF is that the delayed component increases with increasing temperature due to the increased thermal energy. If the reverse intersystem crossing rate is high enough to minimize radiationless decay from triplet state, the fraction of re-occupied excited singlet states can potentially reach 75%. The total singlet fraction may be 100%, which far exceeds the statistical spin limit for electrically generated excitons.E-type delayed fluorescence properties are found in an exciplex system or in a single compound. Without being limited to theory, it is believed that E-type delayed fluorescence requires the luminescent material to have a small singlet-triplet energy gap (ΔE S-T). Organic metal-free donor-acceptor luminescent materials may achieve this, if desired. The emission in these materials is often characterized as a donor-acceptor charge transfer ("charge transfer") type emission. The spatial separation of the HOMO and the LUMO in these donor-acceptor type compounds often results in a small ΔE S-T. These states may include CT states. Often donor-acceptor luminescent materials are formed by combining an electron donor moiety such as amino or carbazole derivatives and an electron acceptor moiety such as N-containing six-membered aromatic rings.A first device is provided. The first device comprises a first organic light emitting device further comprising an anode, a cathode, and an emitting layer disposed between the anode and the cathode and comprising a first emitting dopant. The first emissive dopant is organic and does not contain a metal and comprises an electron donor moiety and an electron acceptor moiety. The first emissive dopant has a calculated HOMO energy that is greater than or equal to -4.70 eV and a calculated LUMO energy that is greater than or equal to -1.20 eV. The first emissive dopant has an energy ratio calculated by dividing the T1 energy of the first emissive dopant by ΔE HOMO-LUMO for the first emissive dopant, wherein the energy ratio is at least 0.70. The first emitting dopant also has an energy difference calculated by subtracting the T1 energy of the first emitting dopant from ΔE HOMO-LUMO for the first emitting dopant, wherein the energy difference is less than or equal to 1.00 eV. The first emitting dopant has the following formula I: In the compound of formula I, A represents an aromatic carbocyclic or heterocyclic radical having at least two fused carbocyclic or heterocyclic rings and ring P is an aromatic carbocyclic or heterocyclic ring. Ar 1, Ar 2 and Ar 3 are aryl or heteroaryl and are optionally further substituted. Rings A, Ar 1, Ar 2 and Ar 3 are optionally fused. R 1 represents a mono, di, tri or tetra substitution or no substitution. R 1 is selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof, and n is 2.In one embodiment, the energy difference is less than or equal to 0.90 eV.In one embodiment, the energy ratio is at least 0.73 and the energy difference is less than or equal to 0.90 eV.In one embodiment, the energy ratio is at least 0.73.In one embodiment, A has the formula: wherein X is O, S or Se, Z 1 to Z 8 independently comprise C or N, and the total number of N in Z 1 to Z 8 is at most 1. R is selected from the group consisting of alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof. R 2 represents a mono-, di-, tri- or tetrasubstitution or no substitution, R 3 represents a mono-, di- or trisubstitution or no substitution, and R 4 represents a mono-, di-, tri- or tetrasubstitution or no substitution. R 2, R 3 and R 4 are independently selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof.In one embodiment, the first emissive dopant has the formula: In one embodiment, Ar 1, Ar 2 and Ar 3 are independently selected from the group consisting of phenyl and triphenylene. In one aspect, n is 2.In one embodiment, the ring P, Ar 1, Ar 2 and Ar 3 are phenyl. In one aspect, X is NR and R is aryl or heteroaryl. In one aspect, X is O. In one embodiment, X is S.In one embodiment, the first emissive dopant is selected from the group consisting of: A further first device is provided. The first device comprises a first organic light emitting device further comprising an anode, a cathode, and an emitting layer disposed between the anode and the cathode and comprising a first emitting dopant. The first emissive dopant is organic and does not contain a metal and comprises an electrode donor moiety and an electron acceptor moiety. The first emissive dopant has a calculated HOMO energy that is greater than or equal to -4.70 eV and a calculated LUMO energy that is greater than or equal to -1.20 eV. The first emissive dopant has an energy ratio calculated by dividing the T1 energy of the first emissive dopant by ΔE HOMO-LUMO for the first emissive dopant, wherein the energy ratio is at least 0.70. The first emitting dopant also has an energy difference calculated by subtracting the T1 energy of the first emitting dopant from ΔE HOMO-LUMO for the first emitting dopant, wherein the energy difference is less than or equal to 1.00 eV. The first emissive dopant is selected from the group consisting of: and In donor-acceptor (charge-transfer) emissive charge transfer materials, emission at room temperature may result from the charge transfer (CT) state. Compounds 1, 2, 5, 6, 8, 9, 13 and 14 were synthesized and showed a small (<0.2 eV) ΔE CT-T( defined as the energy difference between the peak with highest energy of CT emission (measured in 2-methyltetrahydrofuran solution at room temperature) and the peak with highest energy of triplet emission measured in 2-methyltetrahydrofuran solution at 77 K). The acceptor moiety of these compounds is dibenzothiophene, dibenzofuran, triphenylene or phenanthrene. Although dibenzothiophene, dibenzofuran, triphenylene and phenanthrene show reversible electrochemical reduction potentials, they are not generally considered strong electron acceptors. Dibenzothiophene, dibenzofuran and triphenylene, however, have high triplet energies and extended electron delocalization, which can stabilize charge when oxidized or reduced. It has unexpectedly been found that by combining dibenzothiophene, dibenzofuran, triphenylene and phenanthrene with strong donors, such as phenylenediamine derivatives (HOMO > 4.7 eV), donor-acceptor systems with charge transfer ("charge transfer") emissions at room temperature with very low ΔE CT-T can be obtained. It is also possible that the ΔE CT-T is a negative number when the CT has a lower energy than the triplet. Figs. 4 and 5 show the photophysics of the compound 1 and the compound 2, respectively.The results for compounds of formula I, such as compounds 1, 2, 5, 6, 8, 9, 13 and 14, show that donor-acceptor CT compounds having high triplet groups and slight electron deficiency can be formed as the electron acceptor moiety, provided that the donor has a strong donor capacity. Phenylenediamine derivatives are strong donors and have been shown to be useful. A further benefit of the compounds of the formula I is that phenylenediamine derivatives can have a high triplet. Therefore, the resulting donor-acceptor CT compound can also have high triplet energies. This is important because donor-acceptor CT compounds with blue emission in the visible spectrum can be obtained. To enable the design of such strong donor / weak acceptor systems, density functional theory (DFT) calculations can be used to predict properties (energy levels and triplet energy) that allow identification of strong donor / weak acceptor systems with small energy differences between the triplet state and the CT emission state (Table 1). DFT calculations were performed on the Gaussian 09 software package with the B3LYP function set and the 6-31g(d) basis set. The comparative compounds C1-C5 are also included to show the effect of strong acceptors (triazene and cyano) on the calculated energy levels.The calculated HOMO and LUMO energies can be used to estimate the energy of the CT state, since the CT emission is determined by the donor and acceptor strengths, i.e., when the HOMO and LUMO are located, respectively. In order to obtain a donor-acceptor CT emission that satisfies the requirement described herein, the triplet energy and the CT emission energy must have a very similar energy, or the CT emission should have a lower energy than the triplet. These requirements can be described by calculating the ratio of the T1 energy of the first emitting dopant by ΔE HOMO-LUMO and / or subtracting the T1 energy of the first emitting dopant from ΔE HOMO-LUMO. In the first case, the T1 / ΔE HOMO-LUMO- ratio should be large, and in the second case, the T1-ΔE HOMO-LUMO- value should be small.There are various types of comparative compounds:Type 1 compounds are compounds with weak donors and strong acceptors, such as Comparative Compound 1 and Comparative Compound 3 (HOMO lower than -4.70 eV and LUMO lower than -1.20 eV). This type of compound may have donor-acceptor charge transfer (donor-acceptor charge transfer) emission as described in Appl. Phys. Lett. 98, 083302 (2011), and J. Am. Chem. Soc., 2012, 134 (36), 14706. With these, a blue emission can be obtained, since the HOMO-LUMO distance of the donor-acceptor-CT compound can be relatively large and the triplet can be relatively high.Type 2 compounds are compounds with strong donors and strong acceptors, such as comparative compound 2 (HOMO higher than -4.70 eV and LUMO lower than -1.20 eV). This type of compound may have a donor-acceptor charge transfer (donor-acceptor charge transfer) emission as described in Chem. Commun., 2012, 48, 9580. They cannot have a blue emission, since the HOMO-LUMO distance of the donor-acceptor-CT compound is relatively small.Type 3 compounds are compounds with weak donors and weak acceptors, such as Comparative Compounds 4 and 5 (HOMO lower than -4.70 eV and LUMO higher than -1.20 eV). This type of compound does not have donor-acceptor charge transfer emission (donor-acceptor charge transfer emission), as shown by the large energy difference between triplet (490 nm) and room temperature emission (407 nm) in Comparative Compound 5.Compounds with CT emission based on strong donors and weak acceptors are preferred over Type 1 and Type 2 CT compounds because (i) blue emission can be obtained due to the relatively large HOMO-LUMO distance and a high triplet energy, and (ii) a strong donor provides hole capture important for trapping charge in the emitting layer to obtain high OLED efficiency. Weak acceptors such as dibenzothiophene, dibenzofuran, triphenylene, pyridine, azacarbazole, and phenanthrene may be more stable in devices, whereas strong acceptors such as cyano, nitro, and heterocycles with a plurality of nitrogen atoms may be less stable in devices.Based on the DFT calculations and the observed CT character (such as the experimental demonstration of solvatochromaticity and / or a very small energy difference between the triplet state and the CT emission state in compounds 1-2, compounds 5-10, compounds 14-15 and compound 47), compounds with CT emission based on strong donors and weak acceptors are predicted to have a calculated HOMO energy of greater than or equal to -4.70 eV, a calculated LUMO energy of greater than or equal to -1.20 eV, a T1 (calculated) / ΔE HOMO-LUMO( calculated) energy ratio of at least 0.70 and a ΔE HOMO-LUMO( calculated) T1 (calculated) energy difference of 1.00 eV or less, which are combined, are particularly suitable defining properties for emissive dopants in OLEDs. TABLE 1: Calculated electronic properties of compounds of formula I TABLE 1: Calculated electronic properties of compounds of formula I1-4,64-0,983,664422,830,770,832-4,63-0,993,644362,870,790,773-4,5-0,993,514482,790,790,724-4,5-13,54492,780,800,725-4,64-0,953,694462,800,760,896-4,63-1,133,54592,720,780,787-4,63-0,953,684482,790,760,898-4,62-13,624372,860,790,769-4,52-0,923,64732,640,730,9610-4,5-0,993,514962,520,720,9911-4,5-0,993,514962,520,720,9912-4,49-1,123,374882,560,760,8113-4,48-1,153,335012,500,750,8314-4,63-1,123,514992,510,711,0015-4,59-1,143,454852,580,750,8716-4,58-1,163,424892,560,750,8617-4,69-1,133,564862,570,720,9918-4,7-1,153,554872,570,720,9819-4,52-0,933,594442,820,780,7720-4,59-1,113,484392,850,820,6321-4,48-0,893,594522,770,770,8222-4,62-1,013,614732,640,730,9723-4,47-1,183,294472,800,850,4924-4,62-0,953,674472,800,760,8725-4,62-1,13,524302,910,830,6126-4,67-0,93,774462,800,740,9727-4,61-0,913,74452,810,760,8928-4,62-1,173,454532,760,800,6929-4,66-0,993,674472,800,760,8730-4,65-1,23,454542,750,800,7031-4,32-0,93,424482,790,820,6332-4,61-13,614682,670,740,9433-4,4-1,063,344502,780,830,5634-4,41-0,933,484462,800,810,6835-4,59-1,033,564252,940,830,6236-4,45-0,873,584492,780,780,8037-4,46-0,883,584582,730,760,8538-4,4-1,13,34412,830,860,4739-4,54-1,043,54892,560,730,9440-4,51-1,043,474882,560,740,9141-4,46-0,953,514402,840,810,6742-4,53-1,013,524402,840,810,6843-4,58-13,584412,830,790,7544-4,53-0,933,64382,850,790,7545-4,64-1,093,554242,950,830,6046-4,55-0,893,664452,810,770,8547-4,84-1,023,824182,990,780,8348-4,56-1,013,554432,820,790,7349-4,66-1,153,514252,940,840,5750-4,58-0,953,634492,780,770,8551-4,59-1,013,584432,820,790,7652-4,68-1,183,54252,940,840,5653-4,63-0,973,664492,780,760,8854-4,57-1,133,444602,720,790,7255-4,66-1,333,334282,920,880,4156-4,59-1,063,534652,690,760,8457-4,65-1,003,654362,870,790,7858-4,70-1,183,524252,940,840,5859-4,60-1,173,434692,670,780,7660-4,69-1,373,324352,870,870,4561-4,63-1,093,544722,650,750,8962-4,58-0,973,614422,830,780,7863-4,67-1,173,54252,940,840,5664-4,51-1,113,44662,680,790,7265-4,61-1,303,314342,880,870,4366-4,52-1,033,494722,650,760,84C1-5,32-1,783,544452,810,790,73C2-4,68-2,22,486122,040,820,44C3-5,43-1,593,844153,010,780,83C4-4,71-0,614,14372,860,701,24C5-4,76-1,23,564502,780,780,78The structures of the comparative compounds C1 to C5 are as follows: Table 2 shows the electrochemical and photophysical data for compounds of formula I. HOMO and LUMO energies were calculated by E ox and E red from cyclic voltammetry using Fc / Fc +( HOMO = 4.8 eV) in dimethylformamide at room temperature. Room temperature emission spectra were obtained in hexanes, toluene, and 2-methyltetrahydrofuran (2-MeTHF). Experimental T1was measured in 2-MeTHF at 77K. The thin film emission at room temperature and the quantum yield were measured in a PMMA film doped with 5 wt% of the compound using a Hamamatsu C9920 absolute PL quantum yield measurement system with integrating sphere and a multi-channel photonic analyzer model C10027. These compounds exhibit a strongly solvatochrome Gaussian emission in solution at room temperature, which demonstrates the donor-acceptor CT nature of the emissive state, and small CT-T1 energies, thereby being suitable for OLED devices.1-5,02-1,913,11412444466460-0,0343082-4,96-2,002,96422443460457-0,0244285-4,99-1,943,054104434564620,04431146-4,97-1,933,04422445460458-0,01443137-4,87-1,892,98Not measuredNot measuredNot measuredNot measuredNot measured435158-4,86-1,892,97Not measuredNot measured469464-0,03443179-4,87-1,952,92Not measuredNot measured4694800,064461813-4,87-1,952,924524905155250,054732814-4,98-2,032,954484865055260,1046924In an embodiment, the first device emits a luminescent radiation at room temperature when a voltage is applied to the organic light emitting device, wherein the luminescent radiation comprises a delayed fluorescence process.In one embodiment, ring A, Ar 1, Ar 2 or Ar 3 are fused to form at least one carbazole moiety.A further first device is provided. The first device comprises a first organic light emitting device further comprising an anode, a cathode, and an emitting layer disposed between the anode and the cathode and comprising a first emitting dopant. The first emissive dopant is organic and does not contain a metal and comprises an electrode donor moiety and an electron acceptor moiety. The first emissive dopant has a calculated HOMO energy that is greater than or equal to -4.70 eV and a calculated LUMO energy that is greater than or equal to -1.20 eV. The first emissive dopant has an energy ratio calculated by dividing the T1 energy of the first emissive dopant by ΔE HOMO-LUMO for the first emissive dopant, wherein the energy ratio is at least 0.70. The first emitting dopant also has an energy difference calculated by subtracting the T1 energy of the first emitting dopant from ΔE HOMO-LUMO for the first emitting dopant, wherein the energy difference is less than or equal to 1.00 eV. The first emissive dopant is selected from the group consisting of: In an embodiment, the emitting layer further comprises a first phosphorescence emitting material.In an embodiment, the emitting layer further comprises a second phosphorescence emitting material.In one embodiment, the first emitting dopant emits white light at room temperature when a voltage is applied to the organic light emitting device.In one embodiment, the first emitting dopant emits blue light having a peak wavelength between about 400 nm to about 500 nm.In one embodiment, the first emitting dopant emits yellow light having a peak wavelength between about 530 nm to about 580 nm.In an embodiment, the first device comprises a second organic light emitting device, wherein the second organic light emitting device is stacked on the first organic light emitting device.In one embodiment, the first device is a consumer product. In an embodiment, the first device is an organic light emitting device. In one embodiment, the first device comprises an illumination unit.Device Examples:In the OLED experiments, all device examples were produced by thermal evaporation in a high vacuum (<10 -7 torr). The anode electrode is made of about 800 Å indium tin oxide (ITO). The cathode consisted of 10 Å LiF followed by 1000 Å Al. All devices were encapsulated with a glass cover sealed with an epoxy resin in a nitrogen glove box (<1 ppm H 2 O and O 2) and a moisture absorbent was included in the assembly.The organic stack of Device Example 1 consisted of, in this order, the ITO surface, 400 Å of Compound A as the hole transport layer (HTL), 300 Å of Compound B doped with 20% of Compound 5 as the emitting layer (EML), 50 Å of Compound C as the ETL2, and 450 Å of Alq 3 as the ETL1.Device Example 2 consists of, in this order, the ITO surface, 400 Å of Compound A as the hole transport layer (HTL), 300 Å of Compound B doped with 20% of Compound 6 as the emitting layer (EML), 50 Å of Compound C as the ETL2, and 450 Å of Alq 3 as the ETL1.The structures of compounds A, B and C are as shown below: Device Example 1 had an external quantum efficiency of 1.5% at 100 cd / m 2. A blue electroluminescence was observed. The CIE coordinates were 0.182, 0.178. Device Example 2 had an external quantum efficiency of 0.9% at 100 cd / m 2. A blue electroluminescence was observed. The CIE coordinates were 0.186, 0.175. Compound 5 was used as an emitter in Device Example 1. The PLQY of the compound 5 was 14%. If it were to behave as a conventional fluorescence emitter (i.e., without "triplet harvesting"), the maximum external quantum efficiency of the device would be about 1.0% assuming that the charge recombination efficiency is one and the light extraction is 30%. The fact that device example 1 had an external quantum efficiency of 1.5% suggests that additional radiation channels such as delayed fluorescence are involved.COMBINATION WITH OTHER MATERIALSThe materials described herein as useful for a particular layer in an organic light emitting device may be used in combination with many different other materials present in the device. The emissive dopants disclosed herein can be used, for example, in conjunction with a wide variety of host materials, transport layers, barrier layers, injection layers, electrodes, and other layers that may be present. The materials described or listed below are non-limiting examples of materials that may be useful in combination with the compounds disclosed herein, and one of ordinary skill in the art may readily consult the literature to determine other materials that may be useful in combination.HIL / HTL:A hole injection / transport material used in the present invention is not particularly limited, and any compound may be used as long as the compound is typically used as a hole injection / transport material. Examples of this material include, but are not limited to, a phthalocyanine or porphyrin derivative, an aromatic amine derivative, an indolecarbazole derivative, a polymer containing fluorocarbon, a polymer with conductivity dopants, a conductive polymer such as PEDOT / PSS, a self-assembling monomer derived from compounds such as phosphonic acid and silane derivatives, a metal oxide derivative such as MoO x, a p-type semiconducting organic compound such as 1,4,5,8,9,12-hexaazatriphenylenehexacarbonitrile, a metal complex, and crosslinkable compounds.Examples of aromatic amine derivatives used in HIL or HTL include, but are not limited to, the following general structures: Each of Ar 1 to Ar 9 is selected from the group consisting of aromatic cyclic hydrocarbon compounds such as benzene, biphenyl, triphenyl, triphenylene, naphthalene, anthracene, phenalene, phenanthrene, fluorene, pyrene, chrysene, perylene, azulene, the group consisting of aromatic heterocyclic compounds such as dibenzothiophene, dibenzofuran, dibenzoselenophene, furan, thiophene, benzofuran, benzothiophene, benzoselenophene, carbazole, indolocarbazole, pyridylindole, pyrrolodipyridine, pyrazole, imidazole, triazole, oxazole, thiazole, oxadiazole, oxatriazole, dioxazole, Thiadiazole, pyridine, pyridazine, pyrimidine, pyrazine, triazine, oxazine, oxathiazine, oxadiazole, indole, benzimidazole, indazole, indoxazine, benzoxazole, benzisoxazole, benzothiazole, quinoline, isoquinoline, cinnoline, quinazoline, quinoxaline, naphthyridine, phthalazine, pteridine, xanthene, acridine, phenazine, phenothiazine, phenoxazine, benzofuropyridine, furodipyridine, benzothienopyridine, thienodipyridine, benzoselenophenopyridine, and selenophenodipyridine, and the group consisting of 2 to 10 cyclic structural units which are groups of the same type or different types, which are selected from the aromatic cyclic hydrocarbon group and the aromatic heterocyclic group and are bonded to each other directly or via at least an oxygen atom, nitrogen atom, sulfur atom, silicon atom, phosphorus atom, boron atom, a chain structural unit and an aliphatic cyclic group. Each Ar is further substituted by a substituent selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof.In one aspect, Ar 1 to Ar 9 are independently selected from the group consisting of: k is an integer from 1 to 20, X 101 to X 108 are C (including CH) or N, Z 101 is NAr 1, O or S, Ar 1 is the same group as defined above.Examples of metal complexes used in HIL or HTL include, but are not limited to, the following general formula: Met is a metal, (Y 101- Y 102) is a bidentate ligand, Y 101 and Y 102 are independently selected from C, N, O, P, and S, L 101 is another ligand; k' is an integer from 1 to the maximum number of ligands that may be bonded to the metal, and k' + k" is the maximum number of ligands that may be bonded to the metal.In one aspect, (Y 101- Y 102) is a 2-phenylpyridine derivative.In another aspect, (Y 101- Y 102) is a carbene ligand.In another aspect, Met is selected from Ir, Pt, Os and Zn.In another aspect, the metal complex has a smallest oxidation potential in solution against an Fc + / Fc pair of less than about 0.6 V.Host:The light emitting layer of the organic EL device of the present invention preferably contains at least one metal complex as a light emitting material, and may contain a host material in which the metal complex is used as a dopant material. Examples of the host material are not particularly limited, and any metal complexes or organic compounds may be used as long as the triplet energy of the host is larger than that of the dopant. While the table below categorizes the host materials preferred for the devices emitting different colors, any host material can be used with any dopant as long as the triplet criteria are met.Examples of metal complexes used as host preferably have the following general formula: Met is a metal, (Y 103- Y 104) is a bidentate ligand, Y 103 and Y 104 are independently selected from C, N, O, P, and S, L 101 is another ligand; k' is an integer from 1 to the maximum number of ligands that may be bonded to the metal, and k' + k" is the maximum number of ligands that may be bonded to the metal.In one aspect, the metal complexes are: (O-N) is a bidentate ligand comprising metal coordinated to the atoms O and N.In another aspect, Met is selected from Ir and Pt.In another aspect, (Y 103- Y 104) is a carbene ligand.Examples of organic compounds used as the host are selected from the group consisting of aromatic cyclic hydrocarbon compounds such as benzene, biphenyl, triphenyl, triphenylene, naphthalene, anthracene, phenalene, phenanthrene, fluorene, pyrene, chrysene, perylene, azulene, the group consisting of aromatic heterocyclic compounds such as dibenzothiophene, dibenzofuran, dibenzoselenophene, furan, thiophene, benzofuran, benzothiophene, benzoselenophene, carbazole, indolocarbazole, pyridylindole, pyrrolodipyridine, pyrazole, imidazole, triazole, oxazole, thiazole, oxadiazole, oxatriazole, dioxazole, thiadiazole, Pyridine, pyridazine, pyrimidine, pyrazine, triazine, oxazine, oxathiazine, oxadiazole, indole, benzimidazole, indazole, indoxazine, benzoxazole, benzisoxazole, benzothiazole, quinoline, isoquinoline, cinnoline, quinazoline, quinoxaline, naphthyridine, phthalazine, pteridine, xanthene, acridine, phenazine, phenothiazine, phenoxazine, benzofuropyridine, furodipyridine, benzothienopyridine, thienodipyridine, benzoselenophenopyridine, and selenophenodipyridine, and the group consisting of 2 to 10 cyclic structural units which are groups of the same type or different types, which are selected from the aromatic cyclic hydrocarbon group and the aromatic heterocyclic group and are bonded to each other directly or via at least an oxygen atom, nitrogen atom, sulfur atom, silicon atom, phosphorus atom, boron atom, a chain structural unit and an aliphatic cyclic group. Each group is further substituted by a substituent selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof.In one aspect, the host compound contains at least one of the following groups in the molecule: R 101 to R 107 are independently selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof, wherein aryl or heteroaryl is defined as corresponding to the aforementioned Ar.k is an integer of 1 to 20, k"' is an integer of 0 to 20.X 101 to X 108 are selected from C (including CH) or N.Z 101 and Z 102 are selected from NR 101, O or S.HBL:A hole blocking layer (HBL) may be used to reduce the number of holes and / or excitons leaving the emitting layer. The presence of such a barrier layer in a device can result in substantially higher efficiencies compared to a similar device lacking a barrier layer. A barrier layer may also be used to confine emission to a desired region of an OLED.In one aspect, the compound used in the HBL contains the same molecule or functional groups used as the host as described above.In another aspect, the compound used in the HBL contains at least one of the following groups in the molecule: k is an integer from 0 to 20, L 101 is another ligand, k' is an integer from 1 to 3.ETL:The electron transport layer (ETL) may include a material capable of transporting electrons. The electron transport layer may be intrinsic (undoped) or doped. Doping may be used to increase conductivity. Examples of the ETL material are not particularly limited, and any metal complexes or organic compounds may be used as long as they are typically used to transport electrons.In one aspect, the compound used in the ETL contains at least one of the following groups in the molecule: R 101 is selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof, wherein aryl or heteroaryl is defined as the Ar mentioned above.Ar 1 to Ar 3 are defined as the above-mentioned Ar, respectively.k is an integer of 1 to 20.X 101 to X 108 are selected from C (including CH) or N.In another aspect, the metal complexes used in the ETL include, but are not limited to, the following general formulas: (O-N) or (N-N) is a bidentate ligand comprising metal coordinated to the atoms O, N or N, N, L 101 is another ligand; k' is an integer from 1 to the maximum number of ligands which may be bonded to the metal.In any of the above compounds used in each layer of the OLED device, the hydrogen atoms may be partially or fully deuterated. Thus, any specifically-indicated substituent such as methyl, phenyl, pyridyl, etc., includes, without limitation, undeuterated, partially deuterated, and fully deuterated versions thereof. Accordingly, classes of substituents include, but are not limited to, alkyl, aryl, cycloalkyl, heteroaryl, etc., undeuterated, partially deuterated, and fully deuterated versions thereof.In addition to and / or in combination with the materials disclosed herein, many hole injection materials, hole transport materials, host materials, dopant materials, exciton / hole barrier materials, electron transport and electron injection materials may be used in an OLED. Non-limiting examples of the materials that may be used in an OLED in combination with materials disclosed herein are given in Table 3 below. Table 3 lists non-limiting classes of materials, non-limiting examples of compounds for each class, and documents disclosing the materials.Hole Injection MaterialsPhthalocyanine and porphyrinic compounds Appl. Phys. Lett. 69, 2160 (1996)"Starburst" triarylamines J. Lumin. 72-74, 985 (1997)CF x- Fluorocarbon Polymer Appl. Phys. Lett. 78, 673 (2001)Conductive polymers (e.g. PEDOT:PSS, polyaniline, polythiophene) Synth. Met. 87, 171 (1997) WO 2007 / 002683Phosphonic Acid and Silane SAMs US 2003 / 0162053Triarylamine or Polythiophene Polymers with Conductivity Dopants and EP 1 725 079 A1Organic compounds containing conductive inorganic compounds such as molybdenum and tungsten oxides US 2005 / 0123751 SID Symposium Digest, 37, 923 (2006) WO 2009 / Germany018009n-type semiconducting organic complexes US 2002 / 0158242Organometallic metal complexes US 2006 / 0240279Crosslinkable compounds US 2008 / 0220265Polythiophene-based polymers and copolymers WO 2011 / 075644 EP 2 350 216Hole Transport MaterialsTriarylamines (e.g. TPD, α-NPD) Appl. Phys. Lett. 51, 913 (1987)U.S. Pat. No. 5,061,569EP 650 955J. Mater. Chem. 3, 319 (1993 )Appl. Phys. Lett. 90, 183503 (2007)Appl. Phys. Lett. 90, 183503 (2007)Triarylamine on Spirofluorene Nucleus Synth. Met. 91, 209 (1997)Arylamine carbazole compounds Adv. Mater. 6, 677 (1994), US 2008 / )0124572Triarylamine with (di)benzothiophene / (di)benzofuran US 2007 / 0278938, US 2008 / 0106190, US 2011 / US / US0163302Indolocarbazoles Synth. Met. 111, 421 (2000)Isoindole compounds Chem. Mater. 15, 3148 (2003)Metal-carbene Complexes US 2008 / 0018221Phosphorescent OLED Host MaterialsRed Host MaterialsArylcarbazoles Appl. Phys. Lett. 78, 1622 (2001)Metal 8-hydroxyquinolates (e.g. Alq 3, BAlq) Nature 395, 151 (1998 )US 2006 / 0202194WO 2005 / / 014551WO 2006 / 072002Metal phenoxy benzothiazole compounds Appl. Phys. Lett. 90, 123509 (2007)Conjugated oligomers and polymers (e.g., polyfluorene) Org. Electron. 1, 15 (2000)Aromatic fused rings WO 2009 / 066779, WO 2009 / 066778, WO 2009 / 063833, US 2009 / 0045731, US 2009 / 0045730, WO 2009 / 008311, US 2009 / 0008605, US 2009 / 0009065Zinc complexes WO 2010 / 056066Chrysene-based Compounds WO 2011 / 086863Green Host MaterialsArylcarbazoles Appl. Phys. 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Lett. 79, 156 (2001)Phenothiazine S-oxide WO 2008 / 132085Silylated five membered nitrogen, oxygen, sulfur or phosphorus dibenzoheterocycles WO 2010 / 079051Azacarbazoles US 2006 / 0121308Electron Transport MaterialsAnthracenebenzoimidazole compounds WO 2003 / 060956US 2009 / 0179554Azatriphenylenderivate US 2009 / 0115316Anthracenebenzothiazole Compounds Appl. Phys. Lett. 89, 063504 (2006)Metal 8-hydroxyquinolates (e.g. Alq 3, Zrq 4) Appl. Phys. Lett. 51, 913 (1987) U.S. Pat. No. 7,230,107Metal hydroxybenzoquinolates Chem. Lett. 5, 905 (1993 )Bathocupine compounds such as BCP, BPhen, etc. Appl. Phys. Lett. 91, 263503 (2007)Appl. Phys. Lett. 79, 449 (2001)Electron-deficient 5-membered ring heterocycles (e.g. triazole, oxadiazole, imidazole, benzoimidazole) Appl. Phys. Lett. 74, 865 (1999 )Appl. Phys. Lett. 55, 1489 (1989 )Jpn. J. Apply. Phys. 32, L 917 (1993)Silo L Compounds Org. Electron. 4, 113 (2003)Arylborane compounds J. Am. Chem. Soc. 120, 9714 (1998 )Fluorinated aromatic compounds J. Am. Chem. Soc. 122, 1832 (2000)Fullerenes (e.g. C60) US 2009 / 0101870Triazine Complexes US 2004 / / US 20040036077Zn-(N^N) complexes U.S. Pat. No. 6,528,187EXPERIMENTALChemical abbreviations used herein are: DCM is dichloromethane, THF is tetrahydrofuran, DMF is dimethylformamide, dba is dibenzylideneacetone. Diphenylamine (9 g, 53.3 mmol) and 1,3-dibromobenzene (25 g, 106.8 mmol) were mixed in toluene (500 mL). Nitrogen was passed through the solution while stirring for 15 min. Pd(OAc) 2(0,18 g, 0.8 mmol), triphenylphosphine (0.84 g, 3.2 mmol), and t BuONa (7.7 g, 80.2 mmol) were added sequentially. The mixture was refluxed overnight under nitrogen. After cooling, the reaction mixture was filtered through a Celite® / silica layer and the solvent was then evaporated. The residue was then purified by column chromatography using hexane as the eluant to afford 13.5 g (60%) of 3-bromo-N,N-diphenylaniline. 1,4-Phenylenediamine (7.2 g, 27.7 mmol) and 3-bromotriphenylamine (6 g, 18.5 mmol) were mixed in 500 mL of dry toluene. Nitrogen was passed through the solution while stirring for 15 min. Pd(OAc) 2(0,045 g, 0.2 mmol), triphenylphosphine (0.21 g, 0.8 mmol), and sodium tert-butoxide (2.9 g, 30.2 mmol) were added sequentially. The mixture was refluxed overnight under nitrogen. After cooling, the reaction mixture was filtered through a Celite® / silica layer and the solvent was then evaporated. The residue was then purified by column chromatography using toluene:hexane (1:1, v / v) as the eluant. The product was further purified by boiling with degassed toluene:heptane (1:10, v / v) to filter off the white solid after cooling to give 5.5 g (59%) of the product. N 1, N 1, N 3- triphenyl-N 3-(4-( phenylamino)phenyl)benzene-1,3-diamine (2.2 g, 4.4 mmol) and 4-iododibenzothiophene (1.6 g, 6.1 mmol) were mixed in toluene (150 mL). Nitrogen was passed through the solution while stirring for 15 min. Pd 2( dba) 3(0,02 g, 0.02 mmol), 2-dicyclohexylphosphino-2',6'-dimethoxybiphenyl (0.035 g, 0.08 mmol) and t BuONa (0.63 g, 6.5 mmol) were added sequentially. The mixture was refluxed overnight under nitrogen. After cooling, the reaction mixture was filtered through a Celite® / silica layer and the solvent was then evaporated. The residue was then purified by column chromatography using toluene:hexane (30%) as the eluant to afford 2.1 g (70%) of Compound 2. This was then suspended in a nitrogen purged mixture of 1.5 ml toluene and 13 ml heptane and refluxed for 2 hours. After cooling, the solids were filtered off and dried to give 1.8 g (60%) of compound 1. Nitrogen was passed through dry toluene (125 mL), Pd 2( dba) 3(0,026 g, 0.029 mmol) and 10% t-Bu 3 P in hexane (0.17 mL, 0.058 mmol) for 15 min, to which was added N 1, N 1, N 3- triphenyl-N 3-(4-( phenylamino)phenyl)benzene-1,3-diamine (2.9 g, 5.8 mmol), 2-bromodibenzothiophene (1.2 g, 4.6 mmol), and sodium tert-butoxide (1.1 g, 11.6 mmol). Nitrogen was passed through the mixture for 15 min and refluxed for 18 hours. After cooling, the reaction mixture was filtered through a silica layer and washed with DCM. The solvent was removed under reduced pressure and the residue was purified by flash chromatography using 20% DCM / hexane to afford compound 2 (2.6 g, 83% yield) as a white solid. N 1, N 1, N 3- triphenyl-N 3-(4-( phenylamino)phenyl)benzene-1,3-diamine (3 g, 6.0 mmol) and 4-iododibenzo[b,d]furan (2.6 g, 8.8 mmol) were mixed in dry toluene (150 mL). Nitrogen was passed through the solution while stirring for 15 min. Pd 2( dba) 3(0,027 g, 0.03 mmol), dicyclohexyl(2',6'-dimethoxy-[1,1'-biphenyl]-3-yl)phosphine (0.055 g, 0.12 mmol) and sodium tert-butoxide (0.86 g, 9.0 mmol) were added sequentially. The mixture was refluxed overnight under nitrogen. After cooling, the reaction mixture was filtered through a Celite® / silica layer and the solvent was then evaporated. The residue was then purified by column chromatography using toluene:hexane (1:3, v / v) as the eluant. The product was further purified by boiling with degassed toluene:heptane (1:10, v / v) to filter off the white solid after cooling to give 3.2 g (79%) of the product. N 1, N 1, N 3- triphenyl-N 3-(4-( phenylamino)phenyl)benzene-1,3-diamine (3 g, 6.0 mmol) and 2-bromodibenzo[b,d]furan (1.4 g, 8.8 mmol) were mixed in 150 mL of dry toluene. Nitrogen was passed through the solution while stirring for 15 min. Pd 2( dba) 3(0,027 g, 0.03 mmol), dicyclohexyl(2',6'-dimethoxy-[1,1'-biphenyl]-3-yl)phosphine (0.055 g, 0.12 mmol) and sodium tert-butoxide (0.86 g, 9.0 mmol) were added sequentially. The mixture was refluxed overnight under nitrogen. After cooling, the reaction mixture was filtered through a celite / silica pad and the solvent was then evaporated. The residue was then purified by column chromatography using toluene:hexane (1:3, v / v) as the eluant. The product was further purified by boiling with degassed toluene:heptane (1:10, v / v) to filter off the white solid after cooling to give 3.2 g (79%) of the product. To a stirred solution of N 1, N 4- diphenylbenzene-1,4-diamine (6.5 g, 20.0 mmol) in toluene (400 mL) was added 4-bromo-N,N-diphenylaniline (7.9 g, 30.1 mmol) and the solution was degassed with nitrogen for 15 min. Palladium(II) acetate (45 mg, 0.2 mmol), triphenylphosphine (210 mg, 0.8 mmol) and sodium tert-butoxide (2.9 g, 30.1 mmol) were added and degassed with nitrogen for an additional 15 min. The reaction was refluxed overnight. The reaction mixture was filtered through Celite® washed with toluene and the filtrate was concentrated under vacuum. It was then subjected to column chromatography with hexane to 50% toluene / hexane to give 5.6 g (48%) of the desired product as a white solid. To a stirred solution of N 1, N 1, N 4- triphenyl-N 4-(4-( phenylamino)phenyl)benzene-1,4-diamine (2.6 g, 5.2 mmol) in toluene (50 mL) was added 4-iododibenzo[b,d]furan (2.0 g, 6.7 mmol) and the solution was degassed with nitrogen for 15 min. Pd 2( dba) 3(4,7 mg, 0.1 mmol), 2-dicyclohexylphosphino-2',6'-dimethoxybiphenyl (8.5 mg, 0.2 mmol) and sodium tert-butoxide (0.7 g, 7.7 mmol) were added and degassed with nitrogen for an additional 15 min. The reaction was refluxed for 3 days. The reaction mixture was filtered through celite, washed with toluene and the filtrate concentrated under vacuum. It was then subjected to column chromatography with hexane to 30% toluene / hexane to give 2.2 g (64%) of the desired product as a white solid. N 1, N 1, N 4- triphenyl-N 4-(4-( phenylamino)phenyl)benzene-1,4-diamine (3 g, 6.0 mmol) and 2-bromodibenzo[b,d]furan (1.4 g, 8.8 mmol) were mixed in dry toluene (150 mL). Nitrogen was passed through the solution while stirring for 15 min. Pd 2( dba) 3(0,027 g, 0.03 mmol), dicyclohexyl(2',6'-dimethoxy-[1,1'-biphenyl]-3-yl)phosphine (0.055 g, 0.12 mmol) and sodium tert-butoxide (0.86 g, 9.0 mmol) were added sequentially. The mixture was refluxed overnight under nitrogen. After cooling, the reaction mixture was filtered through a Celite® / silica layer and the solvent was then evaporated. The residue was then purified by column chromatography using toluene:hexane (1:3, v / v) as the eluant. The product was further purified by boiling with degassed toluene:heptane (1:10, v / v) to filter off the white solid after cooling to give 3.2 g (79%) of the product. To a stirred solution of N 1, N 1, N 4- triphenyl-N 4-(4-( phenylamino)phenyl)benzene-1,4-diamine (2.5 g, 5.0 mmol) in toluene (50 mL) was added 2-bromotriphenylene (1.4 g, 4.5 mmol) and the solution was degassed with nitrogen for 15 min. Pd 2( dba) 3(22,7 mg, 0.02 mmol), 2-dicyclohexylphosphino-2',6'-dimethoxybiphenyl (50.9 mg, 0.1 mmol) and sodium tert-butoxide (0.72 g, 7.5 mmol) were added and degassed with nitrogen for an additional 15 min. The reaction was refluxed overnight. The reaction mixture was filtered through Celite® washed with toluene and the filtrate was concentrated under vacuum. It was then subjected to column chromatography with hexane to 50% toluene / hexane to give 2.7 g (75%) of the desired product as a yellow solid. To a stirred solution of N 1, N 1, N 3- triphenyl-N 3-(4-( phenylamino)phenyl)benzene-1,3-diamine (2.7 g, 5.4 mmol) in toluene (50 mL) was added 9-bromophenanthrene (1.2 g, 4.8 mmol) and degassed with nitrogen for 15 min. Pd 2( dba) 3(49,1 mg, 0.05 mmol), 2-dicyclohexylphosphino-2',6'-dimethoxybiphenyl (88.0 mg, 0.2 mmol) and sodium tert-butoxide (0.77 g, 8.0 mmol) were added and degassed with nitrogen for an additional 15 min. The reaction was refluxed overnight. The reaction mixture was filtered through Celite® washed with toluene and the filtrate was concentrated under vacuum. The residue was then subjected to column chromatography eluting with hexane to 50% toluene / hexane to give 1.7 g (47%) of the desired product as a yellow solid. N 1, N 1, N 4- triphenyl-N 4-(4-( phenylamino)phenyl)benzene-1,4-diamine (2.5 g, 5.0 mmol) and 9-bromophenanthrene (1.1 g, 4.23 mmol) were mixed in dry toluene (150 mL). Nitrogen was passed through the solution while stirring for 15 min. Pd 2( dba) 3(0,027 g, 0.03 mmol), dicyclohexyl(2',6'-dimethoxy-[1,1'-biphenyl]-3-yl)phosphine (0.055 g, 0.12 mmol) and sodium tert-butoxide (0.75 g, 7.8 mmol) were added sequentially. The mixture was refluxed overnight under nitrogen. After cooling, the reaction mixture was filtered through a celite / silica pad and the solvent was then evaporated. The residue was then purified by column chromatography using toluene:hexane (1:3, v / v) as the eluant. The product was further purified by boiling with degassed toluene:heptane (1:10, v / v) to filter off the white solid after cooling to give 2.5 g (75%) of the product. 9H-Carbazole (20 g, 120 mmol) and 2-bromopyridine (13 mL, 132 mmol) were mixed in dry toluene (500 mL). Nitrogen was passed through the solution while stirring for 15 min. Pd 2( dba) 3(0,6 g, 0.66 mmol), dicyclohexyl(2',6'-dimethoxy-[1,1'-biphenyl]-3-yl)phosphine (1 g, 0.24 mmol) and sodium tert-butoxide (20 g, 200 mmol) were added sequentially. The mixture was refluxed overnight under nitrogen. After cooling, the reaction mixture was filtered through a Celite® / silica layer and the solvent was then evaporated. The residue was then purified by silica gel column chromatography using toluene:hexane (1:1, v / v) as the eluant to afford 24.3 g (83%) of the desired product. N-Bromosuccinimide (17.8 g, 100 mmol) in DMF (50 mL) was added slowly to 9-(pyridin-2-yl)-9H-carbazole (24 g, 100 mmol) in THF (250 mL) at 0°C for 30 min. The reaction was allowed to warm to room temperature and stirred overnight. The reaction mixture was then evaporated and extracted with dichloromethane and the organic layer was dried over magnesium sulfate and the solvent was then evaporated. The residue was then purified by column chromatography using toluene:hexane (1:1, v / v) as the eluant and the product was further purified by recrystallization from toluene:ethanol (1:1, v / v) and after cooling, 24.3 g (75%) of the product was obtained as a white solid after filtration. 4-Bromotriphenylamine (10 g, 31 mmol) and aniline (4.3 mL, 46.3 mmol) were mixed in dry toluene (500 mL). Nitrogen was passed through the solution while stirring for 15 min. Pd 2( dba) 3(0,14 g, 0.15 mmol), 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl (0.45 g, 0.7 mmol) and sodium tert-butoxide (4.4 g, 46 mmol) were added sequentially. The mixture was refluxed overnight under nitrogen. After cooling, the reaction mixture was filtered through a Celite® / silica layer and the solvent was then evaporated. The residue was then purified by column chromatography using toluene:hexane (1:1, VN) as eluent. The product was further purified by boiling with degassed toluene:heptane (1:10, v / v) and after cooling, after filtration, 7.3 g (70%) of the product was obtained as a white solid. 3-Bromo-9-(pyridin-2-yl)-9H-carbazole (2.5 g, 7.7 mmol) and N 1, N 1, N 4- triphenylbenzene-1,4-diamine (2.8 g, 8.5 mmol) were mixed in 150 mL of dry toluene. Nitrogen was passed through the solution while stirring for 15 min. Pd 2( dba) 3(0,035 g, 0.04 mmol), dicyclohexyl(2',6'-dimethoxy-[1,1'-biphenyl]-3-yl)phosphine (0.065 g, 0.16 mmol) and sodium tert-butoxide (1.2 g, 11.5 mmol) were added sequentially. The mixture was refluxed overnight under nitrogen. After cooling, the reaction mixture was filtered through a Celite® / silica layer and the solvent was then evaporated. The residue was then purified by column chromatography using toluene as the eluant. The product was further purified by boiling with degassed toluene:heptane (1:10, v / v) and after cooling the yellow solid was filtered off and 3.3 g (75%) of the product was obtained. 3-Bromo-9H-carbazole (10.0 g, 40.6 mmol), iodobenzene (20.7 g, 101.6 mmol), potassium carbonate (28.1 g, 203.2 mmol), copper (2.58 g, 40.6 mmol), 18-crown-6 (10.7 g, 40.6 mmol) in o-dichlorobenzene (400 ml) were stirred and degassed with nitrogen for 15 min. The reaction was refluxed overnight. The reaction mixture was filtered through Celite® washed with toluene and the filtrate was concentrated under vacuum. It was then subjected to column chromatography with 20% DCM / hexane to give 15.6 g (81%) of the desired product as a white solid. To a stirred solution of 3-bromo-9-phenyl-9H-carbazole (7.7 g, 23.8 mmol) in xylenes (200 mL) was added aniline (4.4 g, 47.5 mmol) and degassed with nitrogen for 15 min. Pd 2( dba) 3(1,1 g, 1.2 mmol), 2-dicyclohexylphosphino-2',6'-dimethoxybiphenyl (2.0 mg, 4.8 mmol) and sodium tert-butoxide (3.4 g, 35.6 mmol) were added and degassed with nitrogen for an additional 15 min. The reaction was refluxed overnight. The reaction mixture was filtered through Celite® washed with toluene and the filtrate was concentrated under vacuum. It was then subjected to column chromatography with hexane to 50% toluene / hexane, and 6.4 g (81%) of a white solid was obtained as a desired product. To a stirred solution of 3-bromo-9-phenyl-9H-carbazole (2.0 g, 6.2 mmol) in xylenes (60 mL) was added N,9-diphenyl-9H-carbazol-3-amine (2.4 g, 7.1 mmol) and degassed with nitrogen for 15 min. Pd 2( dba) 3(0,3 g, 0.3 mmol), 2-dicyclohexylphosphino-2',6'-dimethoxybiphenyl (0.5 mg, 1.2 mmol) and sodium tert-butoxide (0.94 g, 9.3 mmol) were added and degassed with nitrogen for an additional 15 min. The reaction was refluxed overnight. The reaction mixture was filtered through celite, washed with toluene and the filtrate concentrated under vacuum. It was then subjected to column chromatography with hexane to 50% toluene / hexane to give 3.4 g (95%) of the desired product as a white solid.

Claims

A first device comprising a first organic light emitting device, further comprising: an anode, a cathode, and an emitting layer disposed between the anode and the cathode and comprising a first emitting dopant, wherein the first emitting dopant is organic and does not contain a metal, wherein the first emitting dopant comprises an electron donor and an electron acceptor moiety, wherein the first emitting dopant has a calculated HOMO energy that is greater than or equal to -4.70 eV, wherein the first emitting dopant has a calculated LUMO energy that is greater than or equal to -1.20 eV, and wherein the first emitting dopant has an energy ratio calculated by dividing the T1 energy of the first emitting dopant by ΔE HOMO-LUMO for the first emitting dopant, wherein the energy ratio is at least 0.70, wherein the first emitting dopant has an energy difference calculated by subtracting the T1 energy of the first emitting dopant from ΔE HOMO-LUMO for the first emitting dopant, wherein the energy difference is less than or equal to 1.00 eV, and wherein the first emitting dopant has the formula: wherein A represents an aromatic carbocyclic or heterocyclic moiety having at least two fused carbocyclic or heterocyclic rings, wherein the ring P is an aromatic carbocyclic or heterocyclic ring, wherein Ar 1, Ar 2 and Ar 3 are aryl or heteroaryl, and are optionally further substituted, wherein the ring A, Ar 1, Ar 2 and Ar 3 are optionally fused, wherein R 1 represents a mono-, di-, tri- or tetra-substitution or no substitution, wherein R 1 is selected from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof, and wherein n is 2.The first device of claim 1, wherein the energy ratio is at least 0.73.The first device of claim 1, wherein the energy difference is less than or equal to 0.90 eV.The first device of claim 1, wherein the energy ratio is at least 0.73 and the energy difference is less than or equal to 0.90 eV.The first device of claim 1, wherein A has the formula: wherein X is O, S, or Se, wherein Z 1 to Z 8 independently comprise C or N, wherein the total number of N in Z 1 to Z 8 is at most 1, wherein R is selected from the group consisting of alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinations thereof, where R 2 represents a mono-, di-, tri- or tetrasubstitution or no substitution, where R 3 represents a mono-, di- or trisubstitution or no substitution, where R 4 represents a mono-, di-, tri- or tetrasubstitution or no substitution, and where R 2, R 3 and R 4 independently from the group consisting of hydrogen, deuterium, halogen, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, The esters may be selected from the group consisting of esters, nitriles, isonitriles, sulfanyls, sulfinyls, sulfonyls, phosphinos, and combinations thereof.The first device of claim 5, wherein the first emissive dopant is of the formula: .The first device of claim 6, wherein Ar 1, Ar 2 and Ar 3 are independently selected from the group consisting of phenyl and triphenylene.The first device of claim 6, wherein the ring P, Ar 1, Ar 2 and Ar 3 are phenyl.The first device of claim 6, wherein X is NR and wherein R is aryl or heteroaryl.The first device of claim 6, wherein X is O.The first device of claim 6, wherein X is S.The first device of claim 6, wherein the first emissive dopant is selected from the group consisting of and are selected.A first device comprising a first organic light emitting device, further comprising: an anode, a cathode, and an emitting layer disposed between the anode and the cathode and comprising a first emitting dopant, wherein the first emitting dopant is organic and does not contain a metal, wherein the first emitting dopant comprises an electron donor and an electron acceptor moiety, wherein the first emitting dopant has a calculated HOMO energy that is greater than or equal to -4.70 eV, wherein the first emitting dopant has a calculated LUMO energy that is greater than or equal to -1.20 eV, and wherein the first emitting dopant has an energy ratio calculated by dividing the T1 energy of the first emitting dopant by ΔE HOMO-LUMO for the first emitting dopant, wherein the energy ratio is at least 0.70, wherein the first emissive dopant has an energy difference calculated by subtracting the T1 energy of the first emissive dopant from ΔE HOMO-LUMO for the first emissive dopant, wherein the energy difference is less than or equal to 1.00 eV, and wherein the first emissive dopant is selected from the group consisting of and are selected.The first device of claim 5, wherein the first device emits a luminescent radiation at room temperature when a voltage is applied to the organic light emitting device, wherein the luminescent radiation comprises a delayed fluorescence process.The first device according to claim 6, wherein the ring A, Ar 1, Ar 2 or Ar 3 is fused so that at least one carbazole unit is formed.A first device comprising a first organic light emitting device, further comprising: an anode, a cathode, and an emitting layer disposed between the anode and the cathode and comprising a first emitting dopant, wherein the first emitting dopant is organic and does not contain a metal, wherein the first emitting dopant comprises an electron donor and an electron acceptor moiety, wherein the first emitting dopant has a calculated HOMO energy that is greater than or equal to -4.70 eV, wherein the first emitting dopant has a calculated LUMO energy that is greater than or equal to -1.20 eV, and wherein the first emitting dopant has an energy ratio calculated by dividing the T1 energy of the first emitting dopant by ΔE HOMO-LUMO for the first emitting dopant, wherein the energy ratio is at least 0.70, wherein the first emissive dopant has an energy difference calculated by subtracting the T1 energy of the first emissive dopant from ΔE HOMO-LUMO for the first emissive dopant, wherein the energy difference is less than or equal to 1.00 eV, and wherein the first emissive dopant is selected from the group consisting of is selected.The first device of claim 1, wherein the emitting layer further comprises a first phosphorescence emitting material.The first device of claim 17, wherein the emitting layer further comprises a second phosphorescence emitting material.

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