Organic light-emitting device

Abstract

The present invention relates to an organic light-emitting device comprising at least one light-emitting layer comprising a mixed host system comprising at least three components, where the first component is an electron-transporting host material e-TMM, the second component is a first hole-transporting host material h-TMM1, the third component is a second hole-transporting host material h-TMM2 which is different from h- TMM1, wherein the first hole-transporting host material h-TMM1 exhibits a giant surface potential slope (GSP-slope) GSPSH1 when deposited by evaporation in vacuum as an organic film on an ITO covered glas substrate, wherein the second hole-transporting host material h-TMM2 exhibits a GSP-slope GSPSH2 when deposited by evaporation in vacuum as an organic film on an ITO covered glas substrate, and wherein the absolute value of the difference between GSPSH1 and GSPSH2 is greater than 30 mV / nm and the invention relates to said mixed host system of said OLED materials.

Description

[0001] P25-014 SC - 1 - Organic light-emitting device Subject-matter of the invention The present invention relates to an organic light-emitting device comprising at least one 5 light-emitting layer comprising a mixed host system comprising at least three components, where the first component is an electron-transporting host material e-TMM, the second component is a first hole-transporting host material h-TMM1, the third component is a second hole-transporting host material h-TMM2 which is different from h- TMM1, wherein the first hole-transporting host material h-TMM1 exhibits a giant surface 10 potential slope (GSP-slope) GSPSH1 when deposited by evaporation in vacuum as an organic film on an ITO covered glas substrate, wherein the second hole-transporting host material h-TMM2 exhibits a GSP-slope GSPSH2 when deposited by evaporation in vacuum as an organic film on an ITO covered glas substrate, and wherein the absolute value of the difference between GSPSH1 and GSPSH2 is greater than 30 mV / nm and the 15 invention relates to said mixed host system of said OLED materials. Background of the invention The structure of organic light-emitting devices (e.g. OLEDs – organic light-emitting diodes or OLECs – organic light-emitting electrochemical cells) in which organic 20 semiconductors are used as functional materials has long been known. Emitting materials used here, aside from fluorescent emitters, are increasingly organometallic complexes which exhibit phosphorescence rather than fluorescence. In general terms, however, there is still a need for improvement in OLEDs, especially also in OLEDs which exhibit triplet emission (phosphorescence). 25 The properties of organic electroluminescent devices are not only determined by the emitters used. Also of particular significance here are especially the other materials used, such as host and matrix materials, hole blocker materials, electron transport materials, hole transport materials and electron or exciton blocker materials, and among 30 these especially the host or matrix materials. Improvements to these materials can lead to distinct improvements to electroluminescent devices. Host materials for use in organic electronic devices are well known. The term "matrix material" is also frequently used in the prior art when what is meant is a host material for phosphorescent emitters. This use of the term is also applicable to the present invention. 35 In the meantime, a multitude of host materials has been developed both for fluorescent and for phosphorescent electronic devices. A further means of improving the performance data of electronic devices, especially of organic electroluminescent devices, is to use combinations of two or three materials, especially host materials or matrix materials. P25-014 SC - 2 - While traditional device parameters such as colour, voltage, efficiency, or stability have been in focus of material development in the past years now the capacitance is gaining more and more interest especially as OLED displays aim for high picture refresh-rates. 5 As modern OLED screens are operated at ever higher refresh rates (from 60Hz in the past to 120Hz or even 240Hz today), the importance of the exact switching characteristics of the OLED stack has increased considerably in recent years. One challenge for display manufacturers in that respect is the adjustment of the switching characteristics of red, green and blue sub-pixels (i.e. OLED stacks) to each other. 10 A crucial parameter with strong impact on the switching characteristics of the OLED stack is its capacitance. As a result, the precise tuning of the capacitance of an OLED stack, both with regard to the operating voltage of the onset of the capacitance curve (beyond the level of the geometric capacitance) and with regard to the maximum capacitance signal, is highly desired. 15 Noguchi, Brütting and coworkers showed in Synthetic Metals 288 (2022), 117101, Figure 7b, that the capacitance of simple bilayer OLEDs can be tuned by materials exhibiting spontaneous orientation polarization (SOP). This means that during the material evaporation process the electrical dipoles of the molecules can show a certain degree of 20 alignment with respect to the evaporation direction resulting for example in case of the well-known emitter Alq3 in the tendency to have the negative end of the dipoles at the side of the Alq3 layer towards the substrate while the positive ends of the dipoles are pointing towards the vacuum. 25 A giant surface potential (GSP) is an electrostatic potential that builds up at the surface of a film as a result of the non-zero net electric polarization within the film in direction of the surface normal due to SOP. As the absolute value of the surface potential resulting from this SOP increases linearly with deposited film thickness, the giant surface potential is usually described as a giant surface potential slope (GSP-slope or GSPS) in 30 consideration of the measured thickness, and in the present disclosure, a surface potential may be the same (e.g. having the same characteristics) as a surface potential slope. A GSPS may be obtained by measuring a surface potential of a target material film in dependence of the material film thickness by using the Kelvin probe measurement. 35 As for example shown by Noguchi et al. (Applied Physics Letters 102, 203306 (2013)) a GSPS is related to a surface charge density (SCD) in the respective material film. An SCD is the net charge density at the film surface that results from the oriented electrical dipoles of the molecules pointing out of the film surface due to SOP. The GSP-slope is P25-014 SC - 3 - proportional to the SCD and the parameters may be used equivalently to quantify the SOP: ^^^ = −^^^^ ⋅ ^^^^.Here, ^^refers to the permittivity constant with a value of ~8.854∙10-12C / (V∙m), ^^refers to the relative permittivity of the investigated material with a value of ~3 for most organic 5 materials used in OLEDs. WO22015084 A1, WO22015107 A1, WO22025714 A1, WO22031033 A1, WO22031036 A1, KR20220018441 A, KR20220018444 A, WO24067501 A1, WO24067503 A1, CN118048147 A, and WO24143996 A1 describe organic light-emitting devices 10 comprising a light-emitting layer comprising three host materials. However, said disclosed three-component matrix-systems fail to provide guidance how to select the three components to precisely tune the capacitance of an OLED stack both with regard to the operating voltage of the onset of the capacitance curve (beyond the level of the geometric capacitance) and with regard to the maximum capacitance signal. 15 The problem addressed by the present invention is therefore that of providing a combination of host materials which are suitable for use in an organic light-emitting device, especially in a phosphorescent OLED, and lead to good device properties, especially with regard to an improved lifetime and which are suitable to precisely tune 20 the operating voltage of the onset of the capacitance curve (beyond the level of the geometric capacitance) and / or the maximum capacitance signal of an OLED stack, and that of providing the corresponding light-emitting device. It has now been found that this problem is solved, and the disadvantages from the prior 25 art are eliminated, by the comination of at least three host materials where the first host material is an electron-transporting host material which is combined with two hole- transporting host materials having different GSP-slopes GSPSH1 and GSPSH2 in a light- emitting layer of an organic light-emitting device, wherein the absolute value of the difference between GSPSH1 and GSPSH2 is greater than 30 mV / nm. The selection of 30 said two hole-transporting host materials having said difference in giant surface potential slope in combination with an electron-transporting host material for production of the light-emitting layer in an organic light-emitting device and adjustment of the concentration ratio between the two hole-transporting host materials in the light-emitting layer in the organic light-emitting device allows to precisely tune the operating voltage of 35 the onset of the capacitance curve (beyond the level of the geometric capacitance) and / or the maximum capacitance signal of said device and leads to very good properties of the device with regard to lifetime, efficiency and operating voltage. It has now been found that through the means as described before an organic light- emitting device can be provided having improved image quality characteristics by having P25-014 SC - 4 - taylored capacitance properties, preferably by tuning the the operating voltage of the onset of the capacitance curve. Summary of the invention 5 The present invention therefore first provides an organic light-emitting device comprising an anode, a cathode, arranged opposite to the anode; and at least one light-emtting layer arranged between the anode and cathode, wherein the at least one light-emitting layer comprises a mixed host system comprising at least three components, where the first component is an electron-transporting host 10 material e-TMM, the second component is a first hole-transporting host material h- TMM1, the third component is a second hole-transporting host material h-TMM2 which is different from h-TMM1, the optional further component is capable of being a host material, wherein the first hole-transporting host material h-TMM1 exhibits a giant surface 15 potential slope (GSP-slope) GSPSH1 when deposited by evaporation in vacuum as an organic film on an ITO covered glas substrate and measured by Kelvin probe, wherein the second hole-transporting host material h-TMM2 exhibits a GSP-slope GSPSH2 when deposited by evaporation in vacuum as an organic film on an ITO covered glas substrate and measured by Kelvin probe, 20 wherein the absolute value of the difference between GSPSH1 and GSPSH2 is greater than 30 mV / nm. The invention further provides a mixed host system comprising at least three components, where the first component is an electron-transporting host material e-TMM, 25 the second component is a first hole-transporting host material h-TMM1, the third component is a second hole-transporting host material h-TMM2 which is different from h- TMM1, the optional further component is capable of being a host material, wherein the first hole-transporting host material h-TMM1 exhibits a giant surface potential slope (GSP-slope) GSPSH1 when deposited by evaporation in vacuum as an 30 organic film on an ITO covered glas substrate and measured by Kelvin probe, wherein the second hole-transporting host material h-TMM2 exhibits a GSP-slope GSPSH2 when deposited by evaporation in vacuum as an organic film on an ITO covered glas substrate and measured by Kelvin probe, wherein the absolute value of the difference between GSPSH1 and GSPSH2 is greater 35 than 30 mV / nm. The invention further provides specific further mixtures, and specific material combinations. The corresponding preferred embodiments as described hereinafter likewise form part of the subject-matter of the present invention. The surprising and P25-014 SC - 5 - advantageous effects are achieved through specific selection of the three components of the mixed-matrix system and especially through the specific selection and molar ratio of the two hole-transporting host materials h-TMM1 and h-TMM2. 5 The invention further provides a method capable of tuning the operating voltage of the onset of the capacitance curve (beyond the level of the geometric capacitance) and / or of the maximum capacitance signal of an organic light-emitting device comprising an anode, a cathode, arranged opposite to the anode; and at least one light-emtting layer arranged between the anode and cathode through combination of at least three host 10 materials in the at least one light-emitting layer of said organic light-emitting device comprising the following steps: - providing at least one electron-transporting host material e-TMM; - providing a first hole-transporting host material h-TMM1 wherein the first hole- transporting host material h-TMM1 exhibits a giant surface potential slope (GSP-slope) 15 GSPSH1 when deposited by evaporation in vacuum as an organic film on an ITO covered glas substrate and measured by Kelvin probe; - providing a second hole-transporting host material h-TMM2 wherein the second hole- transporting host material h-TMM2 exhibits a giant surface potential slope (GSP-slope) GSPSH2 when deposited by evaporation in vacuum as an organic film on an ITO 20 covered glas substrate and measured by Kelvin probe and selecting it in such a way that the absolute value of the difference between GSPSH1 and GSPSH2 is greater than 30 mV / nm; - optionally providing a further component which is capable of being a host material; - depositing e-TMM, h-TMM1, h-TMM2 and optionally the further component together 25 with an emitter by evaporation in vacuum between the anode and cathode thus building the at least one light-emitting layer; - determining the capacitance properties of said light-emitting device and - adjusting the ratio of h-TMM1 and h-TMM2 in the light-emitting layer to tune the operating voltage of the onset of the capacitance curve (beyond the level of the 30 geometric capacitance) and / or the maximum capacitance signal to the intended target value. The at least one light-emitting layer in said method is preferably a green light-emitting layer. 35 Detailed description of the invention As utilized herein, the term “and / or” or “or” may include any and all combinations of one or more of the associated listed items. Throughout the disclosure, the expression such P25-014 SC - 6 - as “at least one of”, “one of”, and s”selected from”, when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list. As utilized herein, the term “hole-transporting host material” is synonymously used with 5 the term “hole-transporting material” or “hole-transport material” or “hole-transport host material”. As utilized herein, the term “electron-transporting host material” is synonymously used with the term “electron-transporting material” or “electron-transport material” or “electron- transport host material”. 10 The organic light-emitting device of the invention is, for example, an organic light- emitting transistor (OLET), an organic field quench device (OFQD), an organic light- emitting electrochemical cell (OLEC), an organic laser diode (O-laser) or an organic light-emitting diode (OLED). The organic light-emitting device or synonymously organic 15 electroluminescent device of the invention is especially an organic light-emitting diode or an organic light-emitting electrochemical cell. The device of the invention is more preferably an OLED. The organic light-emitting device of the invention may comprise in addition to the at least one light-emitting layer (EML) as described before or described above or hereinafter, a 20 hole injection layer (HIL), a hole transport layer (HTL), an electron blocking layer (EBL), an electron transport layer (ETL), an electron injection layer (EIL) and / or a hole blocker layer (HBL), and / or an exciton blocking layer and / or charge generation layers. It is also possible for the device of the invention to include multiple layers from this group selected from EML, HIL, HTL, EBL, ETL, EIL and HBL. 25 The organic light-emitting device of the invention may contain two or more light-emitting layers. At least one of the light-emitting layers is the light-emitting layer of the invention. It is particularly preferable when these emission layers in this case altogether exhibit a plurality of emission maxima between 380 nm and 750 nm, so that altogether white 30 emission results. It should be noted that, for the production of white light, rather than a plurality of emitter compounds, an emitter compound used individually which emits over a broad wavelength range may also be suitable. Systems with three light-emitting layers are particularly preferred, whereby the three layers show blue, green and orange or red emission. As an alternative to the combination described above, a light-emitting layer 35 can also show yellow emission. Such combinations are known in the art. The organic electroluminescence device according to the invention can also be a tandem electroluminescence device, in particular for white-emitting OLEDs. However, the device may also comprise inorganic materials or else layers formed entirely from inorganic materials. P25-014 SC - 7 - It is preferable when the light-emitting layer according to the invention comprises beside of the mixed host system as described before or described above or hereinafter at least one emitter selected from the group of phosphorescent emitters, fluorescent emitters and / or emitters having thermally activated delayed fluorescence. A suitable selection of 5 emitters is described hereinafter. It is preferable when the light-emitting layer according to the invention comprises beside of the mixed host system as described before or described above or hereinafter at least one phosphorescent emitter. A suitable selection of phosphorescent emitters and 10 preferred phosphorescent emitters is described hereinafter. It is preferable when the mixed host system consists of the three components, where the first component is an electron-transporting host material e-TMM, the second component is a first hole-transporting host material h-TMM1, the third component is a second hole- 15 transporting host material h-TMM2 which is different from h-TMM1, wherein the first hole-transporting host material h-TMM1 exhibits a giant surface potential slope (GSP-slope) GSPSH1 when deposited by evaporation in vacuum as an organic film on an ITO covered glas substrate and measured by Kelvin probe, wherein the second hole-transporting host material h-TMM2 exhibits a GSP-slope 20 GSPSH2 when deposited by evaporation in vacuum as an organic film on an ITO covered glas substrate and measured by Kelvin probe, and wherein the absolute value of the difference between GSPSH1 and GSPSH2 is greater than 30 mV / nm. 25 When an organic material with a permanent electrical dipole exibits a preferential orientation in an organic layer in direction of the surface normal, a surface potential is induced in the organic layer due to an electric field generated by the molecular dipoles. This surface potential is called a giant surface potential (GSP). 30 Most phosphorescent emitters may induce a positive GSP. When a layer has a positive GSP, it refers to that negative charges are induced in a direction of an anode on one surface of the layer, and positive charges are induced in a direction of a cathode on the other surface of the layer. 35 A GSP may be obtained by measuring a surface potential of an organic material layer having a certain thickness by utilizing the Kelvin probe. Because of a surface potential value varies and depends on a thickness of an organic material layer, a slope value, that is, a surface potential value (V / nm), may be obtained by measuring surface potentials with respect to one or more suitable thicknesses. P25-014 SC - 8 - For example, the GSP may be measured as follows: 1) Kelvin probe measurement A compound to be measured for instance the first hole-transporting host material h-TMM1 or the second hole-transporting host material h-TMM2 is deposited on a substrate coated 5 with a metal film such as ITO. Next, a (giant) surface potential of the deposited film of the compound is measured by utilizing a Kelvin probe. This process (material deposition and measurement of surface potential by Kelvin probe) is carried out for a plurality of deposited films of the compound having different film thicknesses. The measured giant surface potential values (including a sign) are plotted 10 versus the deposited film thicknesses and a linear fit is applied.The slope of the linear fit corresponds to the GSPS value. Preferably, the organic film is deposited on the substrate at an evaporation rate of 1 Å / s while the substrate is kept at room temperature. It is further preferred to use an ITO (indium tin oxide) covered glass substrate as substrate within this measurement. 15 Further details to GSP-slope of different materials will be provided in the experimental section. 2) Impedance spectroscopy measurement or displacement current measurement (DCM) After a non-polar organic material (for example, ^-NPD) is deposited to a thickness of 100 20 nm, a compound to be measured for instance the first hole-transporting host material h- TMM1 or the second hole-transporting host material h-TMM2 is deposited thereon according to a thickness (for example, 10 nm to 100 nm), and a turn-on voltage (Vin) of capacitance (or displacement current) is measured in dependence of the deposited material thickness. Preferably, the organic film is deposited on the substrate at an 25 evaporation rate of 1 Å / s while the substrate is kept at room temperature. The giant surface potential value (including sign) can be deducted from the slope of Vin versus material thickness. Details of the measurement method can be found in Physics of Organic Semiconductors (ed. W. Brütting), 119–154. Wiley-VCH (2005), Chapter 5. 30 Further details to GSP-slope of different materials will be provided in the experimental section. As described before, the GSP-slope is proportional to the SCD and the parameters may be used equivalently to quantify the SOP: ^^^ = −^^^^ ⋅ ^^^^.35 Here, ^^refers to the permittivity constant with a value of ~8.854∙10-12C / (V∙m), ^^refers to the relative permittivity of the investigated material with a value of ~3 for most organic materials used in OLEDs. P25-014 SC - 9 - The resulting slopes of the giant surface potential are proportional to the SCD, and materials like Alq3 or TPBi which we define here as having SCD < 0 result in a positive giant surface potential slope. Alternatively, based on said described correlation, the SCD of a compound to be 5 measured for instance the first hole-transporting host material h-TMM1 or the second hole-transporting host material h-TMM2 can be determined as described in the following. In the present disclosure we implement the sign convention of the SCD such that a material like Alq3 has a negative surface charge density (SCD < 0). The question of sign 10 convention arises as one could either define the negative ends of the dipoles at the bottom of the evaporated layer as the relevant SCD or the positive ends of the dipoles at the top of the layer, but the magnitude of the surface charge on bottom or top is identical as there is no net charge in the evaporated layer consisting of neutral molecules. 15 An example for a host / transport material with SCD < 0 according to this convention is TPBi (1,3,5-tris(1-phenyl-1H-benzo[d]imidazole-2-yl)benzene), while an example of a host / transport material with SCD > 0 is 6F-2TRZ (2,2-bis[4-(4,6-diphenyl-1,3,5-triazin-2- yl)phenyl]hexafluoropropane), both materials are shown in Nature Materials, VOL 21, July 2022, 819 to 825 (but with the opposite sign convention for the SCD in Table 1 20 therein). The physical unit for SCD is milli-Coulomb per square meter (mC / m2). The surface charge-density of each h-TMM1 (SDCH1) and h-TMM2 (SDCH2) can be determined via impedance spectroscopy in a device having an ITO electrode as anode, a hole injection layer having a thickness of 10 nm, a hole transport layer having a 25 thickness of 100 nm, a layer comprising h-TMM1 or h-TMM2 having a thickness of 40 nm and consisting of h-TMM1 or h-TMM2 in x% by weight together with an auxiliary host having (100-x)% by weight and a 100 nm thick aluminum electrode as cathode and the auxiliary host is 3-[3-[9-(4,6-Diphenyl-1,3,5-triazin-2-yl)-2-dibenzofuranyl]phenyl]-9- phenyl-9H-carbazole. 30 Generally, there is no limitation to the selection of the hole injection material and the hole-transporting material to be used in the test devices for SCD measurements. However, it is recommended to use an HTL with a vanishing SOP and thus vanishing SCD and vanishing GSP like for example the well known material NPB. 35 Regarding the preparation of the test devices for SCD measurement, glass plates with structured ITO (50 nm, indium tin oxide) form the substrates on which the OLEDs are processed. Before evaporation of the materials, the substrates are cleaned in a wet process (using filtered deionized water and the detergent “Extran” of Merck KGaA). P25-014 SC - 10 - Glass substrates are then dried for 15 minutes at 170°C. Subsequently the clean and dry substrates are exposed to an oxygen and subsequently to an argon plasma. The structure of the test devices used for the SCD measurements is represented by an 5 anode which is an ITO electrode, the HIL (Hole Injection Layer) has a thickness of 10 nm and preferably consists of a mixture of HTM1 and PD1 (95%:5%) (meaning HTM1 is present in the layer in a proportion 95 % by volume and PD1 is present in the layer in a proportion of 5 % by volume), the HTL (Hole Transport Layer) has a thickness of 100 nm and preferably consists of HTM1, the test layer has a thickness of 40 nm and consists of 10 the investigated material and 3-[3-[9-(4,6-Diphenyl-1,3,5-triazin-2-yl)-2- dibenzofuranyl]phenyl]-9-phenyl-9H-carbazole (x % by weight : (100-x) % by weight) and the cathode is a 100 nm thick aluminum electrode. The symbol x represents the concentration of the investigated material in the corresponding layer. 15 20 25 All test devices for the SCD measurements are characterized by standard current / voltage / luminance measurements (IUL measurements) assuming a Lambertian emission profile. For the analysis of SCDs, the build-in voltage Ubi is taken from the current / voltage characteristics. 30 The Surface Charge Density (SCD) of the investigated material is determined via dielectric spectroscopy measurements using preferably an Alpha-NB Single-Unit Dielectric Analyzer (Novocontrol technologies) combined with a dielectric interface (Novocontrol ZGS). This setup allows frequency sweeps covering a range from f = 10−2to f = 107Hz. The AC rms voltage UAC is set to 100 mV for all measurements 35 and the superimposed DC bias UDC is varied between -7 and 7 V. The experimental capacitance C-f-UDC curves were analyzed according to the theoretical description in J. Appl. Phys.107, 1–9 (2010) for Utransand CSCDwith a fixed frequency f = 104Hz in order to observe all necessary quantities for the final surface charge density SCD of the material under test is given as P25-014 SC - 11 - with SCDHTL being the surface charge density of the HTL, recommended to be a material having a vanishing GSP slope, thus a vanishing SCD. Here, SCDHTL of HTM1 is measured to be -0.1 mC / m². As mentioned above, the build-in voltage Ubi is taken from 5 the IUL measurements. “A” depicts the active electrode area of the OLED device. Final surface charge density for a material is calculated / extrapolated to 100% of the investigated material from a set of experiments where the concentration of the investigated material is x = 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70% in case of hosts with auxiliary material 3-[3-[9-(4,6-Diphenyl-1,3,5-triazin-2-yl)-2-dibenzofuranyl]phenyl]-9- 10 phenyl-9H-carbazole. In a preferred embodiment of the organic light-emitting device according to the invention, the absolute value of the difference between GSPSH1 and GSPSH2 is greater than 37.5 mV / nm. 15 In a preferred embodiment of the organic light-emitting device according to the invention, the absolute value of the difference between GSPSH1 and GSPSH2 is greater than 45 mV / nm. 20 It is further preferred when at least one of the GSP-slopes GSPSH1 and GSPSH2 measured as described before is smaller than 0 mV / nm. In a further embodiment of the present invention, one of the GSP-slopes GSPSH1 and GSPSH2 is smaller than 0 mV / nm and the other is greater than 0 mV / nm. 25 The preferred embodiments of the GSP-slopes are also applicable to the method according to the invention. Generally, there is no restriction to the host materials e-TMM, h-TMM1 and h-TMM2, 30 especially regarding their chemical structure. A preferred electron-transporting host material as e-TMM is characterized by fulfilling the following conditions: -2.4 eV > LUMO CV > -2.9 eV, 35 where LUMO CV stands for the LUMO energy of the electron-transporting host material (LUMO means lowest unoccupied molecular orbital) which is determined by cyclic voltammetry. P25-014 SC - 12 - A preferred hole-transporting host material as h-TMM1 or as h-TMM2 is further characterized by fulfilling the following conditions: HOMO CV > -5.5 eV and LUMO CV > -2.2 eV, 5 where HOMO CV stands for the HOMO energy and LUMO CV stands for the LUMO energy of the hole-transporting host material (LUMO means lowest unoccupied molecular orbital and HOMO means highest occupied molecular orbital) which is determined by cyclic voltammetry. 10 The HOMO CV of the hole-transporting host material such as h-TMM1 or h-TMM2 is preferably ≥ -5.45 eV and even more preferably ≥ -5.4 eV. For cyclic voltammetry measurements, a potentiostat from Metronon µAUTOLAB type III in a three-electrode-setup is preferably used including working-electrode (Au), counter 15 electrode (Pt) and reference-electrode (Ag / AgCl, KCl 3M). Oxidation is preferably measured in methylene chloride (DCM) and reduction is preferably measured in tetrahydrofuran (THF) and tetrabutylammonium hexafluorophosphate (0.11 M) is preferably added as electrolyte. Ferrocene or decamethylferrocene can be used as internal standard. 20 The triplet energy level T1 of a material is defined as the relative excitation energy (in eV) of the triplet state having the lowest energy which arises from an quantum-chemical energy calculation. To evaluate the triplet transition energy, both ground state singlet (S0) and triplet geometries (T1) are optimized at the B3LYP / 6-31G* level of theory. 25 Subsequently, vibrations are calculated at the same computational level, and resulting zero-point energies are computed. The adiabatic, zero-point energy corrected energy difference is considered as the triplet transition energy (ZPE = zero-point energy): ∆% = %&'^^(3*+^, ,-.. / 0^ − %^1^(3*+^, ,-.. ^^^ + 2^%&' − 2^%^1For all calculations, the Gaussian16 program package is employed. 30 Preferably, each host material to be used according to the invention has a T1 level > +2.3 eV. Such host materials e-TMM, h-TMM1 and h-TMM2 qualify as host materials for a green light-emitting layer. In one embodiment of the invention, the host materials e- TMM, h-TMM1 and h-TMM2 preferably do not qualify as host materials for a red light- 35 emitting layer. Preferably, the chosen emitter and the host materials of the light-emitting layer according to the invention have a glass transition temperature Tg of > 110°C, determined according to DIN 51005 (version 2005-08). P25-014 SC - 13 - Preferably, the deviation in evaporation temperature (^Tevap) of two host materials from the at least three component matrix-system is ≤ 10°C. Tevap may be determined by measuring TGA in vacuum and recording the temperature 5 at which 5% weight loss is observed. Preferably, the deviation in evaporation temperature (^Tevap) of the three host materials e-TMM, h-TMM1 and h-TMM2 is ≤ 10°C, more preferably ≤ 5°C. In case the mixed host-system according to the invention comprises or consists of the 10 three components e-TMM, h-TMM1 and h-TMM2 fulfilling this condition of ^Tevap, this mixed host system constitutes a premix system that can be used as the sole material source in the vapor deposition of the host materials for the light-emitting layer and have a constant mixing ratio in the vapor deposition. In this way, it is possible in a simple and rapid manner to achieve the vapor deposition of a layer with homogeneous distribution 15 of the components without the need for precise actuation of a multitude of material sources. There follows a description of the first hole-transporting material h-TMM1 and its further preferred embodiments that is / are present in the device of the invention. The preferred 20 embodiments of the first hole-transporting material h-TMM1 are also applicable to the mixture of the invention and the method of the invention. In a preferred embodiment of the invention, the first hole-transporting material h-TMM1 comprise a structural element of formula (A), 25 30 formula (A), where * indicates the binding site to the remainder of the material h-TMM1; R is the same or different at each instance and is D, F, CN, or an aryl group having 6 to 40 carbon atoms or a heteroaryl group having 5 to 40 ring atoms which may 35 both be partially or fully deuterated; a, b at each instance are independently 0, 1, 2, 3 or 4; and c is 0, 1, 2 or 3. P25-014 SC - 14 - In the present disclosure, "D" or "D atom" denotes deuterium. The degree of deuteration, expressed in mol%, means the proportion of H atoms that are replaced by deuterium. Since deuterated compounds are often a mixture of compounds that differ in the exact position and the exact proportion of D atoms, the degree of deuteration denotes the 5 average proportion of H atoms that are replaced by D. With a degree of deuteration of 50mol%, an average of 50mol% of the H atoms in the compound are replaced by D, so that the degree of deuteration is average. An aryl group in the context of this invention contains 6 to 40 aromatic ring atoms, 10 preferably carbon atoms. A heteroaryl group in the context of this invention contains 5 to 40 ring atoms, where the ring atoms include carbon atoms and at least one heteroatom, with the proviso that the sum total of carbon atoms and heteroatoms adds up to at least 5. The heteroatoms are preferably selected from N, O and / or S. An aryl group is understood here to mean either a simple aromatic cycle, i.e. phenyl, derived from 15 benzene, or a fused aryl group, i.e. derived from naphthalene, anthracene, phenanthrene, triphenylene, but also includes aromatic ring systems such as biphenyl, terphenyl, quaterphenyl, dimethylfluorenyl, diphenylfluorenyl or spirobifluorenyl. A heteroaryl group is understood here to mean a simple heteroaromatic cycle, for example derived from pyridine, pyrimidine or thiophene, or a fused heteroaryl group, for example 20 derived from dibenzofurane, dibenzothiophene, carbazole, quinoline or isoquinoline, but also includes heteroaromatic ring systems such as bipyridyl. An aryl group having 6 to 18 carbon atoms is therefore preferably phenyl, naphthyl, phenanthryl, biphenyl, terphenyl or triphenylenyl with no restriction in the attachment of the aryl group as substituent. The aryl or heteroaryl group in the context of this invention may bear one or 25 more radicals, where the substituent is described below. If no such substituent is described, the aryl group or heteroaryl group is not substituted. The aryl and heteroaryl groups are preferably partially deuterated or fully deuterated. An aryl group (synonymously used in this disclosure an aromatic ring system) or a 30 heteroaryl group (synonymously used in this disclosure a heteroaromatic ring system) which has 5-40 ring atoms and may be joined to the aromatic or heteroaromatic system via any desired positions is understood to mean, for example, groups derived from benzene, naphthalene, anthracene, benzanthracene, phenanthrene, benzophenanthrene, pyrene, chrysene, perylene, fluoranthene, benzofluoranthene, 35 naphthacene, pentacene, benzopyrene, biphenyl, biphenylene, terphenyl, terphenylene, fluorene, spirobifluorene, dihydrophenanthrene, dihydropyrene, tetrahydropyrene, cis- or trans-indenofluorene, cis- or trans-monobenzoindenofluorene, cis- or trans- dibenzoindenofluorene, truxene, isotruxene, spirotruxene, spiroisotruxene, furan, benzofuran, isobenzofuran, dibenzofuran, thiophene, benzothiophene, P25-014 SC - 15 - isobenzothiophene, dibenzothiophene, pyrrole, indole, isoindole, carbazole, indolocarbazole, indenocarbazole, pyridine, quinoline, isoquinoline, acridine, phenanthridine, benzo-5,6-quinoline, benzo-6,7-quinoline, benzo-7,8-quinoline, phenothiazine, phenoxazine, pyrazole, indazole, imidazole, benzimidazole, 5 naphthimidazole, phenanthrimidazole, pyridimidazole, pyrazinimidazole, quinoxalinimidazole, oxazole, benzoxazole, naphthoxazole, anthroxazole, phenanthroxazole, isoxazole, 1,2-thiazole, 1,3-thiazole, benzothiazole, pyridazine, benzopyridazine, pyrimidine, benzopyrimidine, quinoxaline, 1,5-diazaanthracene, 2,7- diazapyrene, 2,3-diazapyrene, 1,6-diazapyrene, 1,8-diazapyrene, 4,5-diazapyrene, 10 4,5,9,10-tetraazaperylene, pyrazine, phenazine, phenoxazine, phenothiazine, fluorubine, naphthyridine, azacarbazole, benzocarboline, phenanthroline, 1,2,3-triazole, 1,2,4- triazole, benzotriazole, 1,2,3-oxadiazole, 1,2,4-oxadiazole, 1,2,5-oxadiazole, 1,3,4- oxadiazole, 1,2,3-thiadiazole, 1,2,4-thiadiazole, 1,2,5-thiadiazole, 1,3,4-thiadiazole, 1,3,5-triazine, 1,2,4-triazine, 1,2,3-triazine, tetrazole, 1,2,4,5-tetrazine, 1,2,3,4-tetrazine, 15 1,2,3,5-tetrazine, purine, pteridine, indolizine and benzothiadiazole. An aromatic ring system having 6 to 18 carbon atoms as ring atoms is preferably selected from phenyl, 1,2-biphenyl, 1,3-biphenyl, 1,4-biphenyl, dimethylfluorenyl, naphthyl, phenanthryl and triphenylenyl, which may be substituted by one or more radicals, where the substituent is described hereinafter. 20 A preferred heteroaromatic ring system having 10 to 18 ring atoms is preferably selected from dibenzofuranyl and dibenzothiophenyl, which may be substituted by one or more radicals, where the substituent is described hereinafter. A cyclic alkyl group in the context of this invention is understood to mean a monocyclic, 25 bicyclic or polycyclic group. In the context of the present invention, a straight-chain, branched or cyclic C1- to C20- alkyl group is understood to mean, for example, the methyl, ethyl, n-propyl, i-propyl, cyclopropyl, n-butyl, i-butyl, s-butyl, t-butyl, cyclobutyl, 2-methylbutyl, n-pentyl, s-pentyl, t-pentyl, 2-pentyl, neopentyl, cyclopentyl, n-hexyl, s-hexyl, t-hexyl, 2-hexyl, 3-hexyl, 30 neohexyl, cyclohexyl, 1-methylcyclopentyl, 2-methylpentyl, n-heptyl, 2-heptyl, 3-heptyl, 4-heptyl, cycloheptyl, 1-methylcyclohexyl, n-octyl, 2-ethylhexyl, cyclooctyl, 1- bicyclo[2.2.2]octyl, 2-bicyclo[2.2.2]octyl, 2-(2,6-dimethyl)octyl, 3-(3,7-dimethyl)octyl, adamantyl, trifluoromethyl, pentafluoroethyl, 2,2,2-trifluoroethyl, 1,1-dimethyl-n-hex-1-yl, 1,1-dimethyl-n-hept-1-yl, 1,1-dimethyl-n-oct-1-yl, 1,1-dimethyl-n-dec-1-yl, 1,1-dimethyl-n- 35 dodec-1-yl, 1,1-dimethyl-n-tetradec-1-yl, 1,1-dimethyl-n-hexadec-1-yl, 1,1-dimethyl-n- octadec-1-yl, 1,1-diethyl-n-hex-1-yl, 1,1-diethyl-n-hept-1-yl, 1,1-diethyl-n-oct-1-yl, 1,1- diethyl-n-dec-1-yl, 1,1-diethyl-n-dodec-1-yl, 1,1-diethyl-n-tetradec-1-yl, 1,1-diethyl-n- hexadec-1-yl, 1,1-diethyl-n-octadec-1-yl, 1-(n-propyl)cyclohex-1-yl, 1-(n-butyl)cyclohex- P25-014 SC - 16 - 1-yl, 1-(n-hexyl)cyclohex-1-yl, 1-(n-octyl)cyclohex-1-yl and 1-(n-decyl)cyclohex-1-yl radicals. The abbreviation Ar5 is the same or different at each instance and is an aryl group or 5 heteroaryl group which has 5 to 40 ring atoms and may be substituted by one or more R7radicals, where the R7radical is defined as described above or hereinafter. In the context of the present invention, a straight-chain, branched or cyclic alkenyl group is understood to mean ethenyl, propenyl, butenyl, pentenyl, cyclopentenyl, hexenyl, 10 cyclohexenyl, heptenyl, cycloheptenyl, octenyl, cyclooctenyl or cyclooctadienyl. In the context of the present invention, a straight-chain, branched or cyclic alkynyl group is understood to mean ethynyl, propynyl, butynyl, pentynyl, hexynyl, heptynyl or octynyl. The radical R in formula (A) or in the compounds of the formulae (1A) to (1G) as 15 described below, is preferably the same or different at each instance D, or an aryl group having 6 to 18 carbon atoms which may be partially or fully deuterated or a heteroaryl group having 5 to 20 ring atoms which may be partially or fully deuterated. Particularly preferably, the radical R is at each occurrence D. Consequently, the 20 structural element of formula (A) is preferably partially or fully deuterated. Consequently, the compounds of formulae (1A) to (1G) are preferably partially or fully deuterated. In a further embodiment of the first hole-transporting host material h-TMM1 consists beside of the structural element of formula (A) one of the structural elements of formulae 25 30 , 35 P25-014 SC - 17 - 5 10 15 20 25 30 35 , P25-014 SC - 18 - 5 10 # indicates the binding site to formula (A) marked with *; Ar5 is the same or different at each instance and is an aromatic or heteroaromatic ring system which has 5 to 40 ring atoms and may be substituted by one or more R7radicals; 15 R6at each instance is the same or different and is D, F, CN, a straight-chain alkyl group having 1 to 20 carbon atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, where the alkyl, alkenyl or alkynyl group may in each case be substituted by one or more R7radicals and where one or more nonadjacent CH2 groups may 7720 be replaced by Si(H)2, Si(R )2, C=O, NH, NR , O, S, CONH or CONR7, or an aromatic or heteroaromatic ring system which has 5 to 60 ring atoms and which may be partially or completely deuterated in each case; it is also possible here for two R6radicals together to form an aromatic, heteroaromatic, aliphatic, or heteroaliphatic ring system; R7is the same or different at each inst825 ance and is D, F, Cl, Br, I, N(R )2, CN, NO2, OR8, SR8, Si(R8)3, B(OR8)2, C(=O)R8, P(=O)(R8)2, S(=O)R8, S(=O)2R8, OSO2R8, a straight-chain alkyl group having 1 to 20 carbon atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, where the alkyl, alkenyl or alkynyl group may in each case be substituted by on830 e or more R radicals and where one or more nonadjacent CH2groups may be replaced by Si(R8)2, C=O, NR8, O, S or CONR8, or an aromatic or heteroaromatic ring system which has 5 to 40 ring atoms and which may be partially or completely deuterated in each case; at the same time, two or more R7radicals together may form an aromatic, 35 heteroaromatic, aliphatic or heteroaliphatic ring system; R8is the same or different at each instance and is H, D, F or an aliphatic, aromatic or heteroaromatic organic radical, especially a hydrocarbyl radical, having 1 to 20 carbon atoms, in which one or more hydrogen atoms may also be replaced by F; P25-014 SC - 19 - s is the same or different at each instance and is 0, 1, 2, 3 or 4; t is the same or different at each instance and is 0, 1, 2 or 3; and u is the same or different at each instance and is 0, 1 or 2. 5 Preferred compounds of the first hole-transporting host material h-TMM1 are therefore compouns of formulae (1A) to (1G), 10 15 20 25 30 35 P25-014 SC - 20 - 5 10 15 20 25 30 35 , P25-014 SC - 21 - 5 10 15 20 , where R, a, b, c, Ar5, R6, R7, R8, s, t and u have one of the meanings as described before or as preferably described before, or in the following. The invention further provides the organic light-emitting device as described above, 25 wherein the first hole-transporting host material h-TMM1 conforms to one of the formulae (1A), (1B), (1C), (1D), (1E), (1F) and (1G) as described above. In a particularly preferred embodiment of the light-emitting device, mixture or method according to the invention, the first hole-transporting host material h-TMM1 is selected 30 from compounds of formulae (1A), (1B), or (1G) as described before. In a preferred embodiment of the light-emitting device, mixture or method according to the invention, the first hole-transporting host material h-TMM1 is selected from compounds of formula (1B) as described before or preferred embodiments thereof. 35 In compounds of the formulae (1A), (1B), (1C), (1D), (1E), (1F) and (1G), Ar5 is preferably selected from the group of Ar-1 to Ar-20, P25-014 SC - 23 - 5 10 15 20 25 , , 30 where the symbols and indices used are as follows: Y3is O, S, NAr4or C(R5)2, preferably O or NAr4; R3is H or R6; the dashed bond is the bond to the remainder of the formulae (1A), (1B), (1C), (1D), (1E), (1F) and (1G); 35 R5is methyl or phenyl which may be partially or fully deuterated or two R5are bonded to form a spirobifluorenyl which may be partially or fully deuterated; Ar means phenylene which may be partially or fully deuterated; m is 0 or 1 and Ar4is phenyl, biphenyl or terphenyl which may be partially or fully deuterated. P25-014 SC - 24 - In Y3, R5is preferably methyl. In Ar-15 to Ar-18, Y3is preferably O or NAr4. 5 In Ar-15 to Ar-18, m is preferably 0. In Ar-1 to Ar-20, R3is preferably H or D. Within the group of Ar-1 to Ar-20, the groups Ar-1, Ar-2, Ar-15, Ar-16, Ar-17 and / or Ar-18 are preferred where the symbols and indices used have the meaning as described or 10 preferably described before. In compounds of the formulae (1A), (1B), (1C), (1D), (1E), (1F) and (1G), Ar5 is therefore particularly preferably selected from the group of Ar-1, Ar-2, Ar-15, Ar-16, Ar-17 and Ar- 18 where the symbols and indices used have the meaning as described or preferably 15 described before. In compounds of the formulae (1A), (1B), (1C), (1D), (1E), (1F) and (1G) or in preferred compounds of the formulae (1A), (1B), (1C), (1D), (1E), (1F) and (1G), R6stands preferably independently for D or phenyl, where H atoms of said phenyl group may be 20 substituted through D. In a preferred embodiment of the light-emitting device or mixed host system according to the invention, the first hole-transporting host material h-TMM1 according to compounds of formulae (1A), (1B), (1C), (1D), (1E), (1F) and (1G) as described before or preferably 25 described before is partially or fully deuterated. If the compounds of formulae (1A), (1B), (1C), (1D), (1E), (1F) and (1G) are deuterated compounds, it is possible in their manufacture, if the preparation is chosen by reacting a non-deuterated compound of one of formulae (1A), (1B), (1C), (1D), (1E), (1F) and (1G) 30 with a source of deuteration or if deuterated starting compounds are chosen in the preparation which are a mixture of deuterated starting compounds, to obtain a mixture of deuterated products of the same basic chemical structure which differ only in the degree of deuteration and / or the deuteration patterns. 35 Such mixtures of deuterated compounds of the same basic chemical structure of one of the formulae (1A), (1B), (1C), (1D), (1E), (1F) and (1G) or of the basic structure of the preferred embodiments, which differ only in the degree of deuteration and / or the deuteration patterns, are understood by the term “one compound of the formulae (1A), (1B), (1C), (1D), (1E), (1F) and (1G)” within the meaning of the invention. P25-014 SC - 25 - In a preferred embodiment of the first hole-transporting host material h-TMM1 of the formulae (1A), (1B), (1C), (1D), (1E), (1F) and (1G), as previously described or preferably described, the average degree of deuteration is at least 50 mol% to 90 mol%, 5 more preferably 70 mol% to 100 mol%. Corresponding deuteration methods are known to the person skilled in the art and are described, for example, in KR2016041014 A, WO2017 / 122988 A1, KR2020052820 A, KR101978651 B1 and WO2018 / 110887 A1 or in Bulletin of the Chemical Society of 10 Japan, 2021, 94(2), 600-605 or Asian Journal of Organic Chemistry, 2017, 6(8), 1063- 1071. A suitable method of deuterating a compound by exchange of one or more hydrogen atoms for deuterium atoms is a treatment of the compound to be deuterated in the 15 presence of a platinum catalyst or palladium catalyst and a deuterium source. The term “deuterium source” means any compound that contains one or more deuterium atoms and is able to release them under suitable conditions. The platinum catalyst is preferably dry platinum on charcoal, preferably 5% dry platinum 20 on charcoal. The palladium catalyst is preferably dry palladium on charcoal, preferably 5% dry palladium on charcoal. A suitable deuterium source is D2O, benzene-d6, chloroform-d, acetonitrile-d3, acetone-d6, acetic acid-d4, methanol-d4 or toluene-d8. A preferred deuterium source is D2O or a combination of D2O and a fully deuterated organic solvent. A particularly preferred deuterium source is the combination of D2O with 25 a fully deuterated organic solvent, where the fully deuterated solvent here is not restricted. Particularly suitable fully deuterated solvents are benzene-d6 and toluene-d8. A particularly preferred deuterium source is a combination of D2O and toluene-d8. The reaction is preferably conducted with heating, more preferably with heating to temperatures between 100°C and 200°C.In addition, the reaction is preferably 30 conducted under pressure. Examples of suitable host materials of the formulae (1A), (1B), (1C), (1D), (1E), (1F) and (1G) are the structures of tables 1 and the structures H1 to H42 given below in table 2. 35 Table 1: P25-014 SC - 34 - P25-014 SC - 35 - 5 10 15 20 25 30 35 P25-014 SC - 36 - 5 10 15 20 25 30 35 P25-014 SC - 37 - P25-014 SC - 38 - The compounds in Tables 1 and 2 are shown in part as fully deuterated compounds for the sake of simplification, whereby these are generally intended to denote compounds that have a degree of deuteration of at least 50 mol%. The degree of deuteration for said fully deuterated compounds in Tables 1 and 2 is therefore between 50 mol% and 100 5 mol% or has a preferred deuteration degree as described herein. For partially deuterated compounds, a D atom means that the corresponding position in the molecule has a degree of deuteration of at least 40 mol%. The preparation of the compounds of the formulae (1A), (1B), (1C), (1D), (1E), (1F) and 10 (1G) or of the compounds from tables 1 and 2 is known to those skilled in the art. The compounds may be prepared by synthesis steps known to the person skilled in the art, for example halogenation, preferably bromination, and a subsequent organometallic coupling reaction, for example Suzuki coupling, Heck coupling or Hartwig-Buchwald coupling. 15 There follows a description of the second hole-transporting material h-TMM2 and its further preferred embodiments that is / are present in the device of the invention. The preferred embodiments of the second hole-transporting material h-TMM2 are also applicable to the mixed host system of the invention and the method of the invention. 20 Generelly, the selection of the second hole-transporting host material h-TMM2 is not limited. The second hole-transporting host material h-TMM2 is different from h-TMM1 and does not include a structural formula (A) as described before or preferred embodiments thereof which is linked to a carbazole or indolocarbazole. In a preferred 25 embodiment of the invention, the hole-transporting host material h-TMM2 is selected from the group consisting of dibenzofuran substituted carbazoles, diarylamino substituted carbazoles, dibenzothiophenes having at least one triphenylene substituent, anthracenes, biscarbazoles, indolocarbazoles, and indolo[3,2,1-JK]carbazoles. 30 Preferred second hole-transporting host materials h-TMM2 correspond to one of the formulae (2A), (2B) and (2C), 35 P25-014 SC - 39 - 5 10 15 20 25 ormua ( ), where the symbols and indices Ar5, R6, s, t and u have a meaning as described before for compounds of formulae (1A) to (1G) and Ar5 does not include the structural formula (A) as described before or preferred embodiments thereof. 30 Preferred compounds of formula (2A) are compounds of formula (2Aa), 35 formula (2Aa), P25-014 SC - 40 - where Ar5, R6, s and t have a meaning as described before or preferably described before and Ar5 does not include the structural formula (A) as described before or preferred embodiments thereof. 5 Preferred compounds of formula (2B) are compounds of formulae (2Ba) to (2Be), 10 15 20 25 30 35 formula (2Bd), P25-014 SC - 41 - 5 formula (2Be), where Ar5, R6, s and u have a meaning as described before or preferably described before. Preferred compounds of formula (2B) are compounds of formulae (2Ba1) to (2Be1), 10 15 20 25 30 35 formula (2Bc1), P25-014 SC - 42 - 5 10 15 ormua ( e ), where Ar5, R6, s and u have a meaning as described before or preferably described before and r is 0, 1, 2, 3, 4 or 5. 20 Preferred compounds of formula (2C) are compounds of formula (2Ca), 25 formula (2Ca), 30 where Ar5, R6, s and t have a meaning as described before or preferably described before. In compounds of the formulae (2Aa1), (2Bb1), (2Bc1), (2Bd1) and (2Be1), r is preferably independently on each occurrence 1, 2, 3, 4 or 5 where a maximum of one R6radical 35 may be different from D. In compounds of the formulae (2A), (2Aa), (2B), (2Ba), (2Bb), (2Bc), (2Bd), (2Be), (2Ba1), (2Bb1), (2Bc1), (2Bd1), (2Be1), (2C), and (2Ca), s is preferably independently P25-014 SC - 43 - on each occurrence 1, 2, 3 or 4 where a maximum of one R6radical may be different from D. In compounds of the formulae (2A), (2Aa), (2C), and (2Ca), t is preferably independently on each occurrence 1, 2 or 3 where a maximum of one R6radical may be different from 5 D. In compounds of the formulae (2B), (2Ba), (2Bb), (2Bc), (2Bd), (2Be), (2Ba1), (2Bb1), (2Bc1), (2Bd1), or (2Be1), u is preferably 1 or 2 where a maximum of one R6radical may be different from D. The sum total of the R6radicals being different from D in compounds of the formulae 10 (2A), (2Aa), (2B), (2Ba), (2Bb), (2Bc), (2Bd), (2Be), (2Ba1), (2Bb1), (2Bc1), (2Bd1), (2Be1), (2C) or (2Ca) is preferably not more than 4, especially preferably not more than 2 and more preferably not more than 1. In a preferred embodiment of the compounds of the formulae (2A), (2Aa), (2B), (2Ba), 15 (2Bb), (2Bc), (2Bd), (2Be), (2Ba1), (2Bb1), (2Bc1), (2Bd1), (2Be1), (2C) and (2Ca) that can be combined in accordance with the invention with the first hole-transporting host material h-TMM1 and the electron-transporting host material e-TMM, as described above or below, R6is the same or different at each instance and is selected from the group consisting of D, F, CN, a straight-chain alkyl group having 1 to 20 carbon atoms or a 20 branched or cyclic alkyl group having 3 to 20 carbon atoms, where the alkyl group may in each case be substituted by one or more R7radicals, or an aromatic or heteroaromatic ring system which has 5 to 60 ring atoms, preferably 5 to 40 ring atoms, and may be substituted in each case by one or more R7radicals. 25 In a preferred embodiment of the compounds of the formulae (2A), (2Aa), (2B), (2Ba), (2Bb), (2Bc), (2Bd), (2Be), (2Ba1), (2Bb1), (2Bc1), (2Bd1), (2Be1), (2C) or (2Ca) that can be combined in accordance with the invention, as described above, R6is the same or different at each instance and is selected from the group consisting of D, or an aromatic or heteroaromatic ring system which has 6 to 30 ring atoms and may be 30 substituted by one or more R7radicals. R6is preferably selected on each occurrence from D, a partially or fully deuterated phenyl group. R6is most preferably selected on each occurrence from D. Preferably, Ar5in compounds of the formulae (2A), (2Aa), (2B), (2Ba), (2Bb), (2Bc), 35 (2Bd), (2Be), (2Ba1), (2Bb1), (2Bc1), (2Bd1), (2Be1), (2C) or (2Ca) is independently selected from phenyl, biphenyl, especially ortho-, meta- or para-biphenyl, triphenylenyl, terphenyl, especially ortho-, meta- or para-terphenyl or branched terphenyl, quaterphenyl, especially ortho-, meta- or para-quaterphenyl or branched quaterphenyl, fluorenyl which may be joined via the 1, 2, 3 or 4 position, spirobifluorenyl which may be P25-014 SC - 44 - joined via the 1, 2, 3 or 4 position, naphthyl, especially 1- or 2-bonded naphthyl, or radicals derived from indole, benzofuran, benzothiophene, carbazole which may be joined via the 1, 2, 3 or 4 position, dibenzofuran which may be joined via the 1, 2, 3 or 4 position, dibenzothiophene which may be joined via the 1, 2, 3 or 4 position, 5 indenocarbazole, indolocarbazole, phenanthrene or triphenylene, each of which may be substituted by one or more R7radicals. Ar5 in compounds of formulae (2A), (2Aa), (2B), (2Ba), (2Bb), (2Bc), (2Bd), (2Be), (2Ba1), (2Bb1), (2Bc1), (2Bd1), (2Be1), (2C) or (2Ca) is preferably deuterated, but not further substituted. 10 More preferably, at least one Ar5 in compounds of the formulae (2A), (2Aa), (2B), (2Ba), 15 , 20 25 30 35 , , P25-014 SC - 45 - 5 , , where R10is H or R7and where R7has a meaning as described before or preferably described before or below. It is preferred that at least one R10is D. 10 In a preferred embodiment of the compounds of the formulae (2A), (2Aa), (2B), (2Ba), (2Bb), (2Bc), (2Bd), (2Be), (2Ba1), (2Bb1), (2Bc1), (2Bd1), (2Be1), (2C) or (2Ca) that can be combined in accordance with the invention, as described above, R7is the same or different at each instance and is selected from the group consisting of D, F, CN, a straight-chain alkyl group having 1 to 20 carbon atoms or a branched or cyclic alkyl 15 group having 3 to 20 carbon atoms, or an aromatic heteroaromatic ring system which has 5 to 40 ring atoms, and which may be partially or completely deuterated in each case. In a particularly preferred embodiment of the compounds of the formulae (2A), (2Aa), (2B), (2Ba), (2Bb), (2Bc), (2Bd), (2Be), (2Ba1), (2Bb1), (2Bc1), (2Bd1), (2Be1), (2C) or 20 (2Ca) that can be combined in accordance with the invention, as described above, R7is the same or different at each instance and is D, CN or an aromatic or heteroaromatic ring system having 6 to 24 ring atoms, especially having 6 to 18 ring atoms. Preferred embodiments of R7are D, CN, phenyl or biphenyl, which are preferably deuterated. More preferably, R7is D. 25 Preferred embodiments of R10are H and D. The preparation of the compounds of the formulae (2A), (2Aa), (2B), (2Ba), (2Bb), (2Bc), (2Bd), (2Be), (2Ba1), (2Bb1), (2Bc1), (2Bd1), (2Be1), (2C) or (2Ca) is generally known, 30 and some of the compounds are commercially available. Suitable compounds of the formula (2A) or (2B) are known, for example, from the following publications: US2023172061 A1, pages 51 to 71 or KR20230154750 A1, on pages 39 to 49, compounds [B-1] to [B-101] and [B-120] to [B-234] or on pages 49 to 53, 35 compounds [C-1] to [C-102]. Suitable compounds of the formula (2C) are known, for example, from the following publication: WO2021 / 180625 A1, table 3, pages 131 to 137, and in table 4, pages 137 to 139, which may also be partly or fully deuterated. P25-014 SC - 46 - In case the second hole-transporting host material h-TMM2 is a deuterated compound, it is possible that this host material is a mixture of deuterated compounds of the same basic chemical structure, which differ only in the degree of deuteration and / or the deuteration pattern. The remarks on deuterated mixtures and on the preparation of 5 deuterated materials, as previously described for the first hole-transporting host material h-TMM1, apply here accordingly. In a preferred embodiment of h-TMM2 as described before or preferably described before, the latter is a mixture of deuterated compounds of the formulae (2), (2a), (3), (3a), (3b), 10 (3c), (3d), (3e), (3a1), (3b1), (3c1), (3d1), (3e1), (4) and (4a) as described above, wherein the average deuteration level of these compounds is at least 10 mol% to 100 mol%, preferably 50 mol% to 95 mol%, more preferably 70 mol% to 90 mol%. For a combination with the first hole-transporting host material h-TMM1 and the electron- 15 transporting host material e-TMM as described before or in the following, suitable compounds are in particular those of the formulae (2A), (2Aa), (2B), (2Ba), (2Bb), (2Bc), (2Bd), (2Be), (2Ba1), (2Bb1), (2Bc1), (2Bd1), (2Be1), (2C) and (2Ca), as described above or described as preferred, or corresponding compounds in the tables that follow that are covered by these formulae. 20 For a combination with the first hole-transporting host material h-TMM1 and the electron- transporting host material e-TMM as described before or in the following, preferred second-hole transporting host materials h-TMM2 correspond to the formulae (2Aa), (2Ba), (2Ba1), and (2Ca) as described before or preferably described before. 25 For a combination with the first hole-transporting host material h-TMM1 and the electron- transporting host material e-TMM as described before or in the following, preferred second hole-transporting host materials h-TMM2 correspond to the formulae (2Ba) and (2Ba1) as described before or preferably described before. 30 In accordance with the method according to the invention, the molar ratio of the first hole-transporting host material h-TMM1 and the second hole-transporting host material h-TMM2 allows to tune the capacitance of the light-emitting device to the intended target value. 35 An intended target value of the capacitance is sometime necessary because capacitance properties of red, green and blue sub-pixels need to be properly adjusted to each other in order to avoid adverse picture quality artifacts like e.g. color tint under certain luminance values or under certain driving frequencies. P25-014 SC - 47 - Therefore, the molar ratio of h-TMM1 to h-TMM2 to be selected and to be combined with the electron-transporting host material e-TMM so building the mixed-matrix system according to the invention is preferably between 10:1 and 1:10, more preferably between 5 1:5 and 5:1, even more preferably between 1:3 and 3:1. The invention further provides a preferred method capable of tuning the operating voltage of the onset of the capacitance curve (beyond the level of the geometric capacitance) and / or of the maximum capacitance signal of an organic light-emitting 10 device comprising an anode, a cathode, arranged opposite to the anode; and at least one light-emtting layer arranged between the anode and cathode through combination of three host materials in the at least one light-emitting layer of said organic light-emitting device comprising the following steps: - providing one electron-transporting host material e-TMM; 15 - providing a first hole-transporting host material h-TMM1 wherein the first hole- transporting host material h-TMM1 exhibits a giant surface potential slope (GSP-slope) GSPSH1 when deposited by evaporation in vacuum as an organic film on an ITO covered glas substrate and measured by Kelvin probe; - providing a second hole-transporting host material h-TMM2 wherein the second hole- 20 transporting host material h-TMM2 exhibits a giant surface potential slope (GSP-slope) GSPSH2 when deposited by evaporation in vacuum as an organic film on an ITO covered glas substrate and measured by Kelvin probe and selecting it in such a way that the absolute value of the difference between GSPSH1 and GSPSH2 is greater than 30 mV / nm; 25 - depositing e-TMM, h-TMM1, h-TMM2 together with an emitter by evaporation in vacuum between the anode and cathode thus building the at least one light-emitting layer; - determining the capacitance properties of said light-emitting device and adjusting the ratio of h-TMM1 and h-TMM2 in the light-emitting layer to tune the 30 operating voltage of the onset of the capacitance curve (beyond the level of the geometric capacitance) and / or the maximum capacitance signal to the intended target value. In a further embodiment of the present invention, the first hole-transporting host material 35 h-TMM1 is selected from compounds of formula (1A) as described or preferably described and the second hole-transporting host material h-TMM2 is selected from compounds of formulae (2A), (2Aa), (2Ba), (2Ba1) or (2Ca) as described before or preferably described before. P25-014 SC - 48 - In a further embodiment of the present invention, the first hole-transporting host material h-TMM1 is selected from compounds of formula (1B) as described or preferably described and the second hole-transporting host material h-TMM2 is selected from compounds of formulae (2Ba), (2Ba1), (2Aa) or (2Ca) as described before or preferably 5 described before. In a further embodiment of the present invention, the first hole-transporting host material h-TMM1 is selected from compounds of formula (1C) as described or preferably described and the second hole-transporting host material h-TMM2 is selected from compounds of formulae (2A), (2Aa), (2Ba), (2Ba1), or (2Ca) as described before or 10 preferably described before. Further examples of suitable host materials h-TMM2, preferably of the formulae (2A), (2Aa), (2B), (2Ba), (2Bb), (2Bc), (2Bd), (2Be), (2Ba1), (2Bb1), (2Bc1), (2Bd1), (2Be1), (2C) and (2Ca), that can be combined in accordance with the invention with above- 15 detailed compounds of the first hole-transporting host material h-TMM1, as described above, and further with the electron-transporting host material e-TMM, as described below, are the structures shown hereinafter in tables 3 and 4 below. Table 3: 20 25 30 35

[0002]

[0003]  P25-014 SC - 65 - 5 10 15 20 25 30 n in the above Table 3 means the number of D atoms in the respective compound and is 0, or D1 to Dmax, preferably D4 to Dmax. The item n = 0 means that no D atom is 35 included in the compound. The item n = D1 means that one H atom in the respective compound is replaced by a D atom. Dmax means the maximum number of D atoms that is possible in the respective compound. The maximum number Dmax can vary from P25-014 SC - 66 - compound to compound. Depending on the compound, Dmax can assume the following values: 20, 24, 26, 28, 30, 31, 32, 34, 35, 36, 37, 38 and 40. Particularly suitable compounds of the formulae (2A), (2Aa), (2B), (2Ba), (2Bb), (2Bc), 5 (2Bd), (2Be), (2Ba1), (2Bb1), (2Bc1), (2Bd1), (2Be1), (2C) and / or (2Ca) that can be combined in accordance with the invention with above-detailed or below-detailed host materials, as described above, and are used in the organic light-emitting device of the invention or in the mixture, are the compounds H2-1 to H2-47 in table 4. 10 Table 4: 15 20 25 30 35 P25-014 SC - 67 - 5 10 15 20 25 30 35 P25-014 SC - 68 - 5 10 15 20 25 30 35 P25-014 SC - 69 - 5 10 15 20 25 30 35 P25-014 SC - 70 - 5 10 15 20 25 30 35 P25-014 SC - 71 - 5 10 15 20 25 The compounds in Tables 3 and 4 are shown in part as fully deuterated compounds for the sake of simplification, whereby these are generally intended to denote compounds that have a degree of deuteration of at least 50 mol%. The degree of deuteration for said fully deuterated compounds in Tables 3 and 4 is therefore between 50 mol% and 100 30 mol% or has a preferred deuteration degree as described herein. For partially deuterated compounds, a D atom means that the corresponding position in the molecule has a degree of deuteration of at least 40 mol%. There follows a description of the electron-transporting host material e-TMM and its 35 preferred embodiments that is / are present in the device of the invention. The preferred embodiments of electron-transporting host material e-TMM is also applicable to the mixed host system of the invention and the method of the invention. In one embodiment of the device or the mixed host system or the method of the invention, the electron- P25-014 SC - 72 - transporting host material e-TMM is used in the light-emitting layer with compounds of the formulae (1A), (1B), (1C), (1D), (1E), (1F) and (1G) as described above or described as preferred or with the compounds from table 1 or the compounds H1 to H42 together with compounds of the formulae (2A), (2Aa), (2B), (2Ba), (2Bb), (2Bc), (2Bd), (2Be), 5 (2Ba1), (2Bb1), (2Bc1), (2Bd1), (2Be1), (2C) and (2Ca) as described above or described as preferred or with the compounds from table 3 or the compounds H2-1 to H2-47. Generelly, the selection of the electron-transporting host material e-TMM is not limited. In a preferred embodiment of the invention, the electron-transporting material e-TMM is 10 selected from the group consisting of pyrimidines, triazines, diazadibenzofurans, diazadibenzothiophenes, quinazolines, benzo[h]quinazolines and quinoxalines. Suitable electron-transporting host materials correspond to one of the formulae (3A), 15 20 25 30 , 35 formula (3D), P25-014 SC - 73 - 5 formula (3E), where X stands on each occurrence, identically or differently, for N or CR12, preferably for N; L2is the same or different at each instance and is a single bond or an aromatic or 10 heteroaromatic ring system which has 5 to 24 ring atoms and may be substituted in each case by one or more R11radicals; R## is the same or different instance and is D, F, CN, a straight-chain alkyl group having 1 to 20 carbon atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, where the 15 alkyl, alkenyl or alkynyl group may in each case be substituted by one or more R11radicals or an aromatic ring system which has 6 to 24 ring atoms and may be substituted by one or more R11radicals, and two adjacent substituents R## together may form an aromatic, heteroaromatic, aliphatic, heteroaliphatic ring system that may be substituted by one or more R11radicals; 20 Y is the same or different at each instance and is N or CR9, with exclusion of the possibility that two Y alongside one another are both N; V2is O or S; R8is the same or different at each instance and is H, D, F or an aliphatic, aromatic or heteroaromatic organic radical, especially a hydrocarbyl radical, having 1 to 20 25 carbon atoms, in which one or more hydrogen atoms may also be replaced by F; R9is the same or different at each instance and is H, D, F, Cl, Br, I, N(R8)2, CN, NO2, OR8, SR8, Si(R8)3, B(OR8)2, C(=O)R8, P(=O)(R8)2, S(=O)R8, S(=O)2R8, OSO2R8, a straight-chain alkyl group having 1 to 20 carbon atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 30 20 carbon atoms, where the alkyl, alkenyl or alkynyl group may in each case be substituted by one or more R12radicals and where one or more nonadjacent CH2 groups may be replaced by Si(R8)2, C=O, NR8, O, S or CONR8, or an aromatic or heteroaromatic ring system which has 5 to 40 ring atoms and may be substituted in each case by one or more R12radicals; at the same time, two or more R935 radicals together may form an aromatic, heteroaromatic, aliphatic or heteroaliphatic ring system; R11is the same or different at each instance and is D, F, Cl, Br, I, N(R8)2, CN, NO2, OR8, SR8, Si(R8)3, B(OR8)2, C(=O)R8, P(=O)(R8)2, S(=O)R8, S(=O)2R8, OSO2R8, a P25-014 SC - 74 - straight-chain alkyl group having 1 to 20 carbon atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, where the alkyl, alkenyl or alkynyl group may in each case be substituted by one or more R8radicals and where one or more nonadjacent CH2 5 groups may be replaced by Si(R8)2, C=O, NR8, O, S or CONR8, or an aromatic or heteroaromatic ring system which has 5 to 40 ring atoms and which may be partially or completely deuterated in each case; at the same time, two or more R11radicals together may form an aromatic, heteroaromatic, aliphatic or heteroaliphatic ring system; 10 R12at each instance is the same or different and is D, F, CN, a straight-chain alkyl group having 1 to 20 carbon atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, where the alkyl, alkenyl or alkynyl group may in each case be substituted by one or more R11radicals and where one or more nonadjacent CH2 groups may be 15 replaced by Si(H)2, Si(R11)2, C=O, NH, NR11, O, S, CONH or CONR11, or an aromatic or heteroaromatic ring system which has 5 to 60 ring atoms and which may be partially or completely deuterated in each case; it is also possible here for two R12radicals together to form an aromatic, heteroaromatic, aliphatic, or heteroaliphatic ring system; 20 Ar6 is the same or different at each instance and is an aromatic or heteroaromatic ring system which has 5 to 40 ring atoms and may be substituted by one or more R11radicals; b1 is 0, 1, 2, 3, or 4; b2 is 0, 1, 2, or 3. 25 The invention further provides an organic light-emitting device, comprising an anode, a cathode, arranged opposite to the anode, and at least light-emitting layer arranged between the anode and cathode, as described before, wherein the first component of the mixed host system is an electron-transporting host material e-TMM corresponding to one 30 of the formulae (3A), (3B), (3C), (3D), and (3E), or preferable corresponding to one of the formulae (3A), (3B) or (3Ba) as described before or as described hereinafter. Suitable compounds of the formula (3A) are known, for example, from the following publications: WO2007 / 077810A1, WO2008 / 056746A1, WO2010 / 136109A1, 35 WO2011 / 057706A2, WO2011 / 160757A1, WO2012 / 023947A1, WO2012 / 048781A1, WO2013 / 077352A1, WO2013147205A1, WO2013 / 083216A1, WO2014 / 094963A1, WO2014 / 007564A1, WO2014 / 015931A1, WO2015 / 090504A2, WO2015 / 105251A1, WO2015 / 169412A1, WO2016 / 015810A1, WO2016 / 013875A1, WO2016 / 010402A1, WO2016 / 033167A1, WO2017 / 178311A1, WO2017 / 076485A1, WO2017 / 186760A1, P25-014 SC - 75 - WO2018 / 004096A1, WO2018 / 016742A1, WO2018 / 123783A1, WO2018 / 159964A1, WO2018 / 174678A1, WO2018 / 174679A1, WO2018 / 174681A1, WO2018 / 174682A1, WO2019 / 177407A1, WO2019 / 245164A1, WO2019 / 240473A1, WO2019 / 017730A1, WO2019 / 017731A1, WO2019 / 017734A1, WO2019 / 145316A1, 5 WO2019 / 121458A1,WO2020 / 130381A1, WO2020 / 130509A1, WO2020 / 169241A1, WO2020 / 141949A1, WO2021 / 066623A1, WO2021 / 101220A1, WO2021 / 037401A1, WO2021 / 180614A1, WO2021 / 239772A1, WO2022 / 015084A1, WO2022 / 025714A1, WO2022 / 055169A1, EP3575296A1, EP3591728A1, US2014 / 0361254A1, US2014 / 0361268A1, KR20210036304A, KR20210036857A, KR2021147993A, 10 JP2011 / 160367A2 and JP2017 / 107992A2. Suitable compounds of the formula (3B) are known, for example, from the following publications: WO2015 / 182872A1, WO2015 / 105316A1, WO2017 / 109637A1, WO2018 / 060307A1, WO2018 / 151479A2, WO2018 / 088665A2, WO2018 / 060218A1, 15 WO2018 / 234932A1, WO2019 / 058200A1, WO2019 / 017730A1, WO2019 / 017731A1, WO2019 / 066282A1, WO2019 / 059577A1, WO2020 / 141949A1, WO2020 / 067657A1, WO2022063744A1, WO2022 / 090108A1, WO2022 / 207678A1, WO2023061998A1, KR20170139443A, KR20190036867A, KR2019035308A, KR2021147993A, CN110294753A, CN110437241A, US2016 / 072078A1, US2019 / 148646A1. 20 Suitable compounds of the formula (3C) are known, for example, from the following publications: WO2017 / 160089A1, WO2019 / 017730A1, WO2019 / 017731A1, WO2020 / 032424A1. 25 Suitable compounds of the formula (3E) are known, for example, from the following publications: WO2015 / 093878A1, WO2016 / 033167A1, WO2017 / 183859A1, WO2017 / 188655A1, WO2018 / 159964A1. Preferred compounds of the formula (3A) are compounds of the formulae (3Aa) to (3Ae), 30 35 formula (3Aa), P25-014 SC - 76 - Ar6L2X 5 L2N (R##)a310 ( 15 20 25 30 35 P25-014 SC - 77 - 5 10 formula (3Ad), where W, W1are the same or different at each instance and are O, S, C(RW)2 or N-Ar6; 15 RWis the same or different at each instance and is a straight-chain alkyl group having 1 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, where one or more hydrogen atoms may be replaced by D, F or CN, or an aromatic or heteroaromatic ring system which has 5 to 40 ring atoms and may be substituted by one or more substituents selected from D, 20 F, CN, a straight-chain alkyl group having 1 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, where one or more hydrogen atoms in the alkyl group on the aromatic or heteroaromatic ring system may be replaced by D, F or CN; at the same time, the two RWradicals that bind to the same carbon atom may also form a ring system with 25 one another; A is the same or different at each instance and is CR11or N, where not more than two A groups per cycle are N and where A is C when L2is bonded to that position; a3 is the same or different at each instance and is 0, 1, 2, 3 or 4; 30 b3 is the same or different at each instance and is 0, 1, 2 or 3; is derived from an aryl group which has 6 to 20 ring atoms and may besubstituted by one or more substituents R##; 35 P25-014 SC - 78 - L3is an aromatic ring system having 6 to 40 ring atoms or a heteroaromatic ring system having 5 to 40 ring atoms, which may be substituted by one or more R11radicals; and 5 where L2, X, Ar6, R11and R## have the definitions as described before. X is preferably N. In compounds of the formula (3Aa), W is preferably O or N-Ar6. 10 In compounds of the formula (3Aa), A is preferably the same or different at each instance and is CR11, where A is a carbon atom when L2is bonded to that position. In one preferred embodiment of compounds of formulae (3A) or (3Aa), W is N-Ar6 and L2is preferably independently selected from L-1 to L-13 which may be substituted by one or 15 more radicals R11, 20 25 30 35 , P25-014 SC - 79 - where the dashed bonds are the bonds to the rest of formulae (3A) or (3Aa) and where R11has a meaning as described before or hereinafter. Within L-1 to L-13, R11is preferably D. 5 Particularly preferred compounds of the formulae (3A) and (3Aa) are the compounds of t 10 15 20 25 30 - , 35 P25-014 SC - 80 - 5 10 15 20 25 30 35 P25-014 SC - 81 - 5 formula (3Aa-8), 10 where Ar# is the same or different at each instance and is an aromatic ring system which has 6 to 40 ring atoms and may be substituted by one or more R11radicals; L5is a single bond or an aromatic ring system which has 6 to 40 ring atoms and may be substituted in each case by one or more R11radicals; 15 (R11)x, (R11)y, (R11)x1, (R11)y1represent a monosubstitution, a disubstitution, a trisubstitution or the maximum permissible substitution with the radical R11, R18is the same or different at each instance and is a straight-chain alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 12 carbon atoms, where two radicals R18together may form a monocyclic or polycyclic, aliphatic, aromatic or heteroaromatic ring system wh1120 ich may be substituted by one or more R radicals, where X, L2, Ar6 and R11have a previously mentioned or a previously and subsequently preferred definition. In compounds of the formulae (3Aa-1) to (3Aa-8), all X are preferably N. 25 In compounds of the formulae (3Aa-1) to (3Aa-4) and (3Aa-8), the linkers L2and L5are preferably a bond. In compounds of the formula (3Aa-5), the linker L2is preferably a bond. In compounds of the formulae (3Aa-6) and (3Aa-7), one of the linkers L2is preferably selected from L-1 to L1130 -13 which may be substituted by one or more radicals R as described before or preferably described before. In compounds of the formulae (3Aa-6) and (3Aa-7), one of the linkers L2is particularly preferably selected from L-12 which may be substituted by one or more radicals R11as described before or preferably described before or hereinafter. Said one linker L2is preferably bonded to the diazadibenzofuran or diazadibenzothiophene moiety. T235 he further linkers L within compounds of formula (2Aa- 6) and (2Aa-7) are preferably a bond. In compounds of the formulae (3Aa-1), (3Aa-2), (3Aa-3), (3Aa-4), (3Aa-5) and (3Aa-8), the radicals R11in (R11)x, (R11)y, (R11)x1, (R11)y1are preferably as indicated before or below when they occur, and are most preferably D. P25-014 SC - 82 - In compounds of the formulae (3Aa-6) and (3Aa-7), the radicals R11in (R11)xare preferably as indicated before when they occur, and are most preferably D. In compounds of the formulae (3Aa-6) and (3Aa-7), the radicals R11in (R11)yare preferably 5 as indicated before when they occur, and are most preferably a non-deuterated, partially or fully deuterated aryl group having 6 to 18 C atoms. Preferred compound of the formulae (3A) and (3Ab) are compounds in which one of the linkers L2is preferably selected from L-1 to L-13 which may be substituted by one or 10 more radicals R11as described before or preferably described before or hereinafter. In compounds of the formulae (3Ab), one of the linkers L2is particularly preferably selected from L-1, L-2, L-3, L-8, L-9, L-12 and L-13 which may be substituted by one or more radicals R11as described before or preferably described before or hereinafter. In compounds of the formulae (3Ab), one of the linkers L2is particularly preferably selected 15 from L-12 which may be substituted by one or more radicals R11as described before or preferably described before or hereinafter. In compounds of the formulae (3Ab), one of the linkers L2is particularly preferably selected from L-9 which may be substituted by one or more radicals R11as described before or preferably described before or hereinafter. Said one linker L2is preferably bonded to the 4H-Naphtho[1,2,3,4- 20 def]carbazole moiety of the compounds of formula (3Ab). The further linkers L2within compounds of formula (3Ab) are preferably a bond. Preferred compounds of the formula (3Ab) are the compounds of the formula (3Ab-1), 25 30 formula (3Ab-1), where Ar6, L2, R##, a3, X, (R11)x, (R11)y and (R11)x1 have a meaning as described 35 before or as preferably described herein. Alternatively, preferred compound of the formulae (3A) and (3Ab) are compounds in which all linkers L2are a single bond. P25-014 SC - 83 - Preferred compound of the formula (3Ae) are compounds in which one of the linkers L2is preferably selected from L-1 to L-13 which may be substituted by one or more radicals R11as described before or preferably described before or hereinafter. In compounds of 5 the formulae (3Ae), one of the linkers L2is particularly preferably selected from L-1, L-2, L-3, L-8, L-9, L-12 and L-13 which may be substituted by one or more radicals R11as described before or preferably described before or hereinafter. Said one linker L2is preferably bonded to the carbazole moiety of the compounds of formula (3Ae). The further linkers L2within compounds of formula (3Ae) are preferably a bond. 10 Preferred compounds of the formula (3Ae) are the compounds of the formula (3Ae-1), 15 20 formula (3Ae-1), where Ar6, L2, R##, a3, X, (R11)x, (R11)y and (R11)x1 have a meaning as described before or as preferably described herein. 25 Preferred compound of the formulae (3A) and (3Ac) are compounds in which W1is preferably selected from O or C(RW)2, where RWhas a meaning as described before. In this embodiment it is preferred that RWis methyl or that the two RWradicals that bind to the same carbon atom preferably form a ring system with one another. In compounds of the formula (3Ac), one of the linkers L2is preferably a bond or a linker selected from L-1 30 to L-13 which may be substituted by one or more radicals R11as described before or preferably described before or hereinafter. In compounds of formula (3Ac), one of the linkers L2is particularly preferably selected from a bond or the linkers L-1, L-2 and L-3 which may be substituted by one or more radicals R11as described before or preferably described before or hereinafter. Said one linker L2is preferably bonded to the carbazole 35 containing moiety of the compounds of formula (3Ac). The further linkers L2within compounds of formula (3Ac) are preferably a bond. Alternatively, all the linkers L2within the compounds of formula (3Ac) are preferably a bond. P25-014 SC - 84 - In a preferred embodiment of compounds of formula (3Ac), W1is C(RW)2, where RWis methyl or two RWradicals that bind to the same carbon atom form a ring system with one another and all linkers L2are a bond. 5 In compounds of the formula (3Ad), L3is preferably a heteroaromatic ring system which has 9 to 30 ring atoms and may be substituted by one or more R11radicals. Preferred compounds of the formulae (3A) and (3Ad) are the compounds of the formulae 10 15 20 25 30 - , 35 P25-014 SC - 85 - 5 10 formula (3Ad-3), where (R11)x, (R11)y, represent a monosubstitution, a disubstitution, a trisubstitution or the 15 maximum permissible substitution with the radical R11, R18is the same or different at each instance and is a straight-chain alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 12 carbon atoms, where two radicals R18together may form a monocyclic or polycyclic, aliphatic, aromatic or heteroaromatic ring system which may be substituted by one or more R11radicals, 20 L6is a single bond or an aromatic or heteroaromatic ring system which has 5 to 24 ring atoms and may be substituted in each case by one or more R11radicals; where X, L2, Ar6 and R11have a previously mentioned or a previously and subsequently preferred definition. 25 In compounds of the formulae (3Ad-1) to (3Ad-3), all X are preferably N. In compounds of the formulae (3Ad-1) to (3Ad-3), the linker L6is preferably a bond or a linker selected from L-1 to L-13 which may be substituted by one or more radicals R11as described before or preferably described before or hereinafter. In compounds of the 30 formulae (3Ad-1) to (3Ad-3), the linker L6is particularly preferably selected from L-1 to L- 7 and L-12 which may be substituted by one or more radicals R11as described before or preferably described before. In compounds of the formulae (3Ad-1) to (3Ad-3), the linker L6is preferably a linker L12 which may be substituted by one or more radicals R11as described before or preferably described before or hereinafter. 35 In compounds of the formulae (3Ad-1) to (3Ad-3), the linker L2is at each occurrence independently preferably a bond or a linker selected from L-1 to L-13 which may be substituted by one or more radicals R11as described before or preferably described P25-014 SC - 86 - before or hereinafter. In compounds of the formulae (3Ad-1) to (3Ad-3), all the linkers L2are particularly preferably a bond. In compx, 5 (R11)y, a . In a pref correspo d before o 10 compou In comp ), (3Aa-6), Ae), and (3A Ar6- 15 21, 20 25 30 35 P25-014 SC - 88 - 5 , 10 where Y3is O, S, NAr4or C(R5)2, the dashed bond is the bond to the remainder of the formulae (3A), (3Aa), (3Aa-1), (3Aa- 2), (3Aa-3), (3Aa-4), (3Aa-5), (3Aa-6), (3Aa-7), (3Aa-8), (3Ab), (3Ab-1), (3Ac), (3Ad), (3Ad-1), (3Ad-2), (3Ad-3), (3Ae), and (3Ae-1); R5is methyl or phenyl which may be partially or fully de515 uterated or two R are bonded to form a spirobifluorenyl which may be partiylly or fully deuterated; Ar means phenylene which may be partially or fully deuterated; m is 0 or 1 and Ar4is phenyl, biphenyl or terphenyl which may be partially or fully deuterated and where 20 R13is H or R11and R11has a meaning as described or preferably described herein. In Y3, the radical R5is preferably methyl. In Ar6-16 to Ar6-19, Y3is preferably O or NAr4. 25 In Ar6-16 to Ar6-19, m is preferably 0. In Ar6-1 to Ar6-21, R13is preferably H or D. In a preferred embodiment of the compounds of the formulae (3A), (3Aa), (3Aa-1), (3Aa- 2), (3Aa-3), (3Aa-4), (3Aa-5), (3Aa-6), (3Aa-7), (3Aa-8), (3Ab), (3Ab-1), (3Ac), (3Ad), 30 (3Ad-1), (3Ad-2), (3Ad-3), (3Ae), and (3Ae-1) that can be combined in accordance with above-detailed first hole-transporting host material h-TMM1 and second hole- transporting host material h-TMM2, as described above, R11is the same or different at each instance and is selected from the group consisting of D, F, CN, a straight-chain alkyl group having 1 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 35 20 carbon atoms, or an aromatic heteroaromatic ring system which has 5 to 40 ring atoms, and which may be partially or completely deuterated in each case. In a particularly preferred embodiment of the compounds of the formulae (3A), (3Aa), (3Aa-1), (3Aa-2), (3Aa-3), (3Aa-4), (3Aa-5), (3Aa-6), (3Aa-7), (3Aa-8), (3Ab), (3Ab-1), P25-014 SC - 89 - (3Ac), (3Ad), (3Ad-1), (3Ad-2), (3Ad-3), (3Ae), and (3Ae-1) that can be combined in accordance with above-detailed first hole-transporting host material h-TMM1 and second hole-transporting host material h-TMM2, as described above, R11is the same or different at each instance and is selected from the group consisting of D or an aromatic or 5 heteroaromatic ring system which has 6 to 30 ring atoms and which may be partially or completely deuterated in each case or is preferably D. The preparation of the compounds of the formulae (3A), (3Aa), (3Aa-1), (3Aa-2), (3Aa- 3), (3Aa-4), (3Aa-5), (3Aa-6), (3Aa-7), (3Aa-8), (3Ab), (3Ab-1), (3Ac), (3Ad), (3Ad-1), 10 (3Ad-2), (3Ad-3), (3Ae), and (3Ae-1) is generally known, and some of the compounds are commercially available. Preferred compounds of the electron-transporting host material e-TMM are compounds of formula (3Ba), 15 20 formula (3Ba), where Y is the same or different at each instance and is N or CR11, with exclusion of the possibility that two Y alongside one another are both N; V2is O or S; 25 a3 is 0, 1, 2, 3 or 4; D is Deuterium, a4 is 0, 1 or 2; L2is the same or different at each instance and is a single bond or an aromatic or heteroaromatic ring system which has 5 to 24 ring atoms and may be substituted 30 in each case by one or more R11radicals; R8is the same or different at each instance and is H, D, F or an aliphatic, aromatic or heteroaromatic organic radical, especially a hydrocarbyl radical, having 1 to 20 carbon atoms, in which one or more hydrogen atoms may also be replaced by F; R9is the same or different at each instance and is H, D, F, Cl, Br, I, N(R8)2, CN, NO2, 35 OR8, SR8, Si(R8)3, B(OR8)2, C(=O)R8, P(=O)(R8)2, S(=O)R8, S(=O)2R8, OSO2R8, a straight-chain alkyl group having 1 to 20 carbon atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, where the alkyl, alkenyl or alkynyl group may in each case be P25-014 SC - 90 - substituted by one or more R12radicals and where one or more nonadjacent CH2 groups may be replaced by Si(R8)2, C=O, NR8, O, S or CONR8, or an aromatic or heteroaromatic ring system which has 5 to 40 ring atoms and may be substituted in each case by one or more R12radicals; at the same time, two or more R95 radicals together may form an aromatic, heteroaromatic, aliphatic or heteroaliphatic ring system; R11is the same or different at each instance and is D, F, Cl, Br, I, N(R8)2, CN, NO2, OR8, SR8, Si(R8)3, B(OR8)2, C(=O)R8, P(=O)(R8)2, S(=O)R8, S(=O)2R8, OSO2R8, a straight-chain alkyl group having 1 to 20 carbon atoms or an alkenyl or alkynyl 10 group having 2 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, where the alkyl, alkenyl or alkynyl group may in each case be substituted by one or more R8radicals and where one or more nonadjacent CH2 groups may be replaced by Si(R8)2, C=O, NR8, O, S or CONR8, or an aromatic or heteroaromatic ring system which has 5 to 40 ring atoms and which may be 15 partially or completely deuterated in each case; at the same time, two or more R11radicals together may form an aromatic, heteroaromatic, aliphatic or heteroaliphatic ring system. Preferred compounds of the formulae (3B) and (3Ba) are compounds where V2is O. 20 In a preferred embodiment of compounds of the formulae (3B) and (3Ba), two Y are N and two Y are independently CR11, where R11has a meaning as described before. In a preferred embodiment of compounds of the formulae (3B) and (3Ba), two Y are N and two Y are independently CR11, where R11is preferably selected from Ar6-1 to Ar6-21 25 as described before where the symbols and indices Y3, R5, Ar, m, Ar4and R13have a meaning as described or preferably described herein. In a preferred embodiment of compounds of the formulae (3B), on occurrence, R# is preferably selected from Ar6-1 to Ar6-21 as described before where the symbols and 30 indices Y3, R5, Ar, m, Ar4and R13have a meaning as described or preferably described herein. Preferred compounds of formula (3B) correspond to formulae (3Aa-6) and (3Aa-7), where R## corresponds to R11, V2is O, two Y are N and two Y are CR11and R935 corresponds to a specific heteroaromatic ring system. Preferred compounds of formula (3B) correspond to formulae (3Bb-1) to (3Bb-4), P25-014 SC - 91 - 5 10 15 20 where V2, L2, R11, R##, b2, and R12have a meaning as described before or as preferably described herein. 25 R9in formula (3Bb-2) is preferably an aryl group having 6 to 24 carbon atoms which may be substituted by R12and R12has a meaning as described before. Preferred compounds of the formula (3Ba) correspond to formulae (3Ba-1), (3Ba-2), (3Ba-3) or (3Ba-4), 30 35 P25-014 SC - 92 - 5 10 15 20 25 30 formula (3Ba-3), 35 P25-014 SC - 93 - 5 10 V2, R11, R12, L2, a3 and a4 have a meaning as described before or as preferably described before and hereinafter. In compounds of formulae (3Ba-1), (3Ba-2), (3Ba-3), (3Ba-4), (3Bb-1), (3Bb-2), (3Bb-3) 15 and (3Bb-4), V2is preferably O. In compounds of formulae (3Ba-1), (3Ba-2), (3Ba-3), (3Ba-4), (3Bb-1), (3Bb-2), (3Bb-3) and (3Bb-4), R11is at each occurrence independently preferably selected from Ar6-1 to Ar6-21 as described before where the symbols and indices Y3, R5, Ar, m, Ar4and R13have a meaning as described or preferably described herein. In compounds of formulae 20 (3Ba-1), (3Ba-2), (3Ba-3), (3Ba-4), (3Bb-1), (3Bb-2), (3Bb-3) and (3Bb-4), R11is particularly preferably selected from Ar6-1 to Ar6-4 as described before where the symbols and indices Y3, R5, Ar, m, Ar4and R13have a meaning as described or preferably described herein. 25 In compounds of formulae (3Ba-1), (3Ba-2), (3Ba-3), (3Ba-4), (3Bb-1), (3Bb-2), (3Bb-3) and (3Bb-4), R12is preferably selected from Ar6-1 to Ar6-21 as described before where the symbols and indices Y3, R5, Ar, m, Ar4and R13have a meaning as described or preferably described herein. In compounds of formulae (3Ba-1), (3Ba-2), (3Ba-3), (3Ba- 4), (3Bb-1), (3Bb-2), (3Bb-3) and (3Bb-4), R12is particularly preferably selected from 30 Ar6-1 to Ar6-11 and Ar6-16 to Ar6-19 as described before where the symbols and indices Y3, R5, Ar, m, Ar4and R13have a meaning as described or preferably described herein. In compounds of formulae (3Ba-1), (3Ba-2), (3Ba-3), (3Ba-4), (3Bb-1), (3Bb-2), (3Bb-3) and (3Bb-4), R12is very particularly preferably selected from Ar6-1 to Ar6-4 as described before where the symbols and indices Y3, R5, Ar, m, Ar4and R13have a meaning as 35 described or preferably described herein. In a preferred embodiment of compounds of the formulae (3B), (3Ba), (3Ba-1), (3Ba-2), (3Ba-3), (3Ba-4), (3Bb-1), (3Bb-2), (3Bb-3) and (3Bb-4), L2is preferably a bond or P25-014 SC - 94 - selected from L-1 to L-13 which may be substituted by one or more radicals R11as described before or preferably described before or hereinafter. In compounds of the formulae (3B), (3Ba), (3Ba-1), (3Ba-2), (3Ba-3), (3Ba-4), (3Bb-1), (3Bb-2), (3Bb-3) and (3Bb-4), the linker L2is particularly preferably a bond or a linker L-1 to L-5 which may be 5 substituted by one or more radicals R11as described before or preferably described before or hereinafter. In compounds of the formulae ((3Ba-1), (3Ba-2), (3Ba-3), (3Ba-4), (3Bb-1), (3Bb-2), (3Bb-3) and (3Bb-4), the linker L2is particularly preferably a bond. In a preferred embodiment of the compounds of the formulae (3B), (3Bb-1), (3Bb-2), 10 (3Bb-3) and (3Bb-4), R## is at each occurrence D. In a preferred embodiment of the compounds of the formulae (3Ba), (3Ba-1), (3Ba-2), (3Ba-3) and (3Ba-4) that can be combined in accordance with the invention, as described above, R11within (R11)a3 is the same or different at each instance and is selected from the group consisting of D, F, CN, a straight-chain alkyl group having 1 to 15 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, or an aromatic heteroaromatic ring system which has 5 to 40 ring atoms, and which may be partially or completely deuterated in each case. In a particularly preferred embodiment of the compounds of the formulae (3Ba), (3Ba-1), (3Ba-2), (3Ba-3) and (3Ba-4) that can be combined in accordance with the invention, as 20 described above, R11within (R11)a3 is the same or different at each instance and is selected from the group consisting of D or an aromatic or heteroaromatic ring system which has 6 to 30 ring atoms and which may be partially or completely deuterated in each case. In a very particularly preferred embodiment of the compounds of the formulae (3Ba), 25 (3Ba-1), (3Ba-2), (3Ba-3) and (3Ba-4) that can be combined in accordance with the invention, as described above, R11within (R11)a3 is D. The preparation of the compounds of the formulae (3B), (3Ba), (3Ba-1), (3Ba-2), (3Ba- 3), (3Ba-4), (3Bb-1), (3Bb-2), (3Bb-3) and (3Bb-4) is generally known, and some of the 30 compounds are commercially available. Particularly preferred compounds of the electron-transporting host material e-TMM are compounds of formulae (3Ab-1), (3Ac), (3Aa-2), (3Aa-4), (3Ad-1) and (3Ba-2) as described before or preferably described before. Very particularly preferred compounds 35 of the electron-transporting host material e-TMM are compounds of formulae (3Ad-1) and (3Ba-2) as described before or preferably described before. In a preferred embodiment of the light-emitting device or mixture according to the invention, the electron-transporting host material e-TMM is partially or fully deuterated. If P25-014 SC - 95 - e-TMM is a deuterated compound, the same remarks on deuterated mixtures and on the preparation of deuterated materials, as previously described for the first and second hole-transporting host materials, apply here accordingly. In a preferred embodiment of the electron-transporting host material e-TMM as 5 described before or preferably described before, the latter is a mixture of deuterated compounds as described above, wherein the average deuteration level of these compounds is at least 10 mol% to 100 mol%, preferably 50 mol% to 95 mol%, more preferably 70 mol% to 90 mol%. 10 Further examples of suitable host materials e-TMM, preferably compounds of the formulae (3A), (3Aa), (3Aa-1), (3Aa-2), (3Aa-3), (3Aa-4), (3Aa-5), (3Aa-6), (3Aa-7), (3Aa- 8), (3Ab), (3Ab-1), (3Ac), (3Ad), (3Ad-1), (3Ad-2), (3Ad-3), (3Ae), (3Ae-1), (3B), (3Ba), (3Ba-1), (3Ba-2), (3Ba-3), (3Ba-4), (3Bb-1), (3Bb-2), (3Bb-3), and (3Bb-4) that can be combined in accordance with the invention with above-detailed compounds of the first 15 and second hole-transporting host material h-TMM1 and h-TMM2, as described above, are the structures shown hereinafter in tables 5 and 6 below. Table 5: 20 25 30 35

[0004]

[0005]

[0006]

[0007] P25-014 SC - 121 - 5 10 15 20 Particularly suitable compounds of the formulae (3A), (3Aa), (3Aa-1), (3Aa-2), (3Aa-3), (3Aa-4), (3Aa-5), (3Aa-6), (3Aa-7), (3Aa-8), (3Ab), (3Ab-1), (3Ac), (3Ad), (3Ad-1), (3Ad- 2), (3Ad-3), (3Ae), (3Ae-1), (3B), (3Ba), (3Ba-1), (3Ba-2), (3Ba-3), (3Ba-4), (3Bb-1), (3Bb-2), (3Bb-3) and (3Bb-4) that can be combined in accordance with the invention, as 25 described above, and are used in the light-emitting device, the mixture or the method of the invention, are the compounds E1 to E66 in table 6. Table 6: 30 35 P25-014 SC - 122 - 5 10 15 20 25 30 35 P25-014 SC - 123 - 5 10 15 20 25 30 35 P25-014 SC - 124 - 5 10 15 20 25 30 35 P25-014 SC - 125 - 5 10 15 20 25 30 35 P25-014 SC - 126 - 5 10 15 20 25 30 35 P25-014 SC - 127 - 5 10 The compounds in Tables 5 and 6 are shown in part as fully deuterated compounds for the sake of simplification, whereby these are generally intended to denote compounds that have a degree of deuteration of at least 50 mol%. The degree of deuteration for said fully deuterated compounds in Tables 5 and 6 is therefore between 50 mol% and 100 mol% or has a preferred deuteration degree as described herein. For partially deuterated 15 compounds, a D atom means that the corresponding position in the molecule has a degree of deuteration of at least 40 mol%. The aforementioned first and second hole-transporting host materials h-TMM1 and h- TMM2 and the embodiments thereof that have been described as preferred may be 20 combined in the device of the invention in any desired manner with the electron- transporting host material e-TMM, preferably an e-TMM of the formulae (3A), (3Aa), (3Aa-1), (3Aa-2), (3Aa-3), (3Aa-4), (3Aa-5), (3Aa-6), (3Aa-7), (3Aa-8), (3Ab), (3Ab-1), (3Ac), (3Ad), (3Ad-1), (3Ad-2), (3Ad-3), (3Ae), (3Ae-1), (3B), (3Ba), (3Ba-1), (3Ba-2), (3Ba-3), (3Ba-4), (3Bb-1), (3Bb-2), (3Bb-3) and (3Bb-4), and the embodiments thereof 25 that have been described as preferred from table 5 or the compounds E1 to E66 from table 6. This applies for the light-emitting device according to the invention as well as the mixed host system and the method according to the invention. 30 The invention therefore relates in a particularly preferred embodiment of the invention to an organic light-emitting device comprising an anode, a cathode, arranged opposite to the anode; and at least one light-emtting layer arranged between the anode and cathode, 35 wherein the at least one light-emitting layer comprises a mixed host system comprising at least three components, where the first component is an electron-transporting host material e-TMM of one of the formulae (3Ab-1), (3Ac), (3Aa-2), (3Aa-4), (3Ad-1) and (3Ba-2) as described before or preferred embodiments thereof, the second component is a first hole-transporting host material h-TMM1 of formula (1B) as described before or P25-014 SC - 128 - preferred embodiments thereof, the third component is a second hole-transporting host material h-TMM2 of formula (2Ba) as described before or preferred embodiments thereof, which is different from h-TMM1 and does not include a structural formula (A) as described before or preferred embodiments thereof, the optional further component is 5 capable of being a host material, wherein the first hole-transporting host material h-TMM1 exhibits a giant surface potential slope (GSP-slope) GSPSH1 when deposited by evaporation in vacuum as an organic film on an ITO covered glas substrate and measured by Kelvin probe, wherein the second hole-transporting host material h-TMM2 exhibits a GSP-slope 10 GSPSH2 when deposited by evaporation in vacuum as an organic film on an ITO covered glas substrate and measured by Kelvin probe, wherein the absolute value of the difference between GSPSH1 and GSPSH2 is greater than 30 mV / nm. 15 The invention therefore relates in a particularly preferred embodiment of the invention to an organic light-emitting device comprising an anode, a cathode, arranged opposite to the anode; and at least one light-emtting layer arranged between the anode and cathode, wherein the at least one light-emitting layer comprises a mixed host system comprising 20 at least three components, where the first component is an electron-transporting host material e-TMM of one of the formulae (3Ad-1) or (3Ba-1) as described before or preferred embodiments thereof, the second component is a first hole-transporting host material h-TMM1 of formula (1B) as described before or preferred embodiments thereof, the third component is a second hole-transporting host material h-TMM2 of formula 25 (2Ba) as described before or preferred embodiments thereof, which is different from h- TMM1 and does not include a structural formula (A) as described before or preferred embodiments thereof, the optional further component is capable of being a host material, wherein the first hole-transporting host material h-TMM1 exhibits a giant surface potential slope (GSP-slope) GSPSH1 when deposited by evaporation in vacuum as an 30 organic film on an ITO covered glas substrate and measured by Kelvin probe, wherein the second hole-transporting host material h-TMM2 exhibits a GSP-slope GSPSH2 when deposited by evaporation in vacuum as an organic film on an ITO covered glas substrate and measured by Kelvin probe, wherein the absolute value of the difference between GSPSH1 and GSPSH2 is greater 35 than 30 mV / nm. Particularly preferred mixtures of the electron-transporting host material of the formulae (3A), (3Aa), (3Aa-1), (3Aa-2), (3Aa-3), (3Aa-4), (3Aa-5), (3Aa-6), (3Aa-7), (3Aa-8), (3Ab), (3Ab-1), (3Ac), (3Ad), (3Ad-1), (3Ad-2), (3Ad-3), (3Ae), (3Ae-1), (3B), (3Ba), (3Ba-1), P25-014 SC - 129 - (3Ba-2), (3Ba-3), (3Ba-4), (3Bb-1), (3Bb-2), (3Bb-3) and (3Bb-4) are mixtures together with the first hole-transporting host material h-TMM1 of the formulae (1A), (1B), (1C), (1D), (1E), (1F) and (1G) and the second hole-transporting host material h-TMM2 of the formulae (2A), (2Aa), (2B), (2Ba), (2Bb), (2Bc), (2Bd), (2Be), (2Ba1), (2Bb1), (2Bc1), 5 (2Bd1), (2Be1), (2C) and / or (2Ca) as described before. Very particularly preferred mixtures are obtained by combination of the compounds E1 to E66 with the compounds H1 to H42 and the compounds H2-1 to H2-47. The following table 7 shows preferred mixtures. The first mixture M1, for example, is a combination of compound E1 with H1 and H2-1. 10 Table 7: 15 20 25 30 35 P25-014 SC - 130 - 5 10 15 20 25 30 35 P25-014 SC - 131 - 5 10 15 20 25 30 35 P25-014 SC - 132 - 5 10 15 20 25 30 35 P25-014 SC - 133 - 5 10 15 20 25 30 35 P25-014 SC - 134 - 5 10 15 20 25 30 35 P25-014 SC - 135 - 5 10 15 20 25 30 35 P25-014 SC - 136 - 5 10 15 20 25 30 35 P25-014 SC - 137 - 5 10 15 20 25 30 35 P25-014 SC - 138 - 5 10 15 20 25 30 35 P25-014 SC - 139 - 5 10 15 20 25 30 35 P25-014 SC - 140 - 5 10 15 20 25 30 35 The concentration of the total of all hole-transporting host materials h-TMM1 and h- TMM2 as described above or described as preferred in the mixed host system of the invention or in the light-emitting layer of the device of the invention is typically in the P25-014 SC - 141 - range from 10% by weight to 95% by weight, preferably in the range from 15% by weight to 90% by weight, more preferably in the range from 15% by weight to 80% by weight, even more preferably in the range from 20% by weight to 70% by weight, very especially preferably in the range from 40% by weight to 80% by weight and most preferably in the 5 range from 50% by weight to 70% by weight, based on the overall mixture of all host materials in the light-emitting layer. The concentration of the total of all electron-transporting host materials e-TMM as described above or described as preferred in the mixed host system of the invention or 10 in the light-emitting layer of the device of the invention is typically in the range from 5% by weight to 90% by weight, preferably in the range from 10% by weight to 85% by weight, more preferably in the range from 20% by weight to 85% by weight, even more preferably in the range from 30% by weight to 80% by weight, very especially preferably in the range from 20% by weight to 60% by weight and most preferably in the range from 15 30% by weight to 50% by weight, based on the overall mixture of all host materials in the light-emitting layer. The present invention also relates to a mixed host system as described before or preferably described before which comprises at least one further compound being 20 capable of being a host material. In a further preferred embodiment of the invention, the at least one light-emitting layer of the organic light-emitting device may have four different matrix materials. These corresponding mixed matrix systems may consist of the matrix materials described for the first hole-transporting host material h-TMM1, the second hole-transporting host 25 material h-TMM2 and the electron-transporting host material e-TMM, but they may also comprise, a fourth matrix material, for example alongside a wide-band-gap material, a bipolar host material, a further electron transport material different from e-TMM or a further hole transport material different from h-TMM1 and h-TMM2. 30 A wide-band gap material is understood herein to mean a material within the scope of the disclosure of US 7,294,849 which is characterized by a band gap of at least 3.5 eV, the band gap being understood to mean the gap between the HOMO and LUMO energy of a material. 35 It is preferable when the light-emitting layer according to the invention comprises beside of the mixed host system as described before or described above at least one emitter selected from the group of phosphorescent emitters, fluorescent emitters and / or emitters having thermally activated delayed fluorescence, preferably a phosphorescent emitter. P25-014 SC - 142 - The term “phosphorescent emitters” typically encompasses compounds where the light is emitted through a spin-forbidden transition from an excited state having higher spin multiplicity, i.e. a spin state > 1, for example through a transition from a triplet state or a state having an even higher spin quantum number, for example a quintet state. This is 5 preferably understood to mean a transition from a triplet state. Suitable phosphorescent emitters (= triplet emitters) are especially compounds which, when suitably excited, emit light, preferably in the visible region, and also contain at least one atom of atomic number greater than 20, preferably greater than 38 and less than 84, 10 more preferably greater than 56 and less than 80, especially a metal having this atomic number. Preferred phosphorescence emitters used are compounds containing copper, molybdenum, tungsten, rhenium, ruthenium, osmium, rhodium, iridium, palladium, platinum, silver, gold or europium, especially compounds containing iridium or platinum. In the context of the present invention, all luminescent compounds containing the 15 abovementioned metals are regarded as phosphorescent emitters. In general, all phosphorescent complexes as used for phosphorescent OLEDs according to the prior art and as known to those skilled in the art in the field of organic electroluminescent devices are suitable. 20 Preferred phosphorescent emitters according to the present invention conform to the formula (I) 25 30 where the symbols and indices for this formula (I) are defined as follows: n+m is 3, n is 1 or 2, m is 2 or 1, X is the same or different at each instance and is N or CR, R is the same or different at each instance and is H, D, F, CN or a branched or linear 35 alkyl group having 1 to 10 carbon atoms or a partly or fully deuterated, branched or linear alkyl group having 1 to 10 carbon atoms or a cycloalkyl group having 4 to 7 carbon atoms, which may be partly or fully substituted by deuterium, or an aromatic heteroaromatic ring system which has 5 to 60 ring atoms and may be partly or fully P25-014 SC - 143 - substituted by deuterium and / or by a branched or linear alkyl group having 1 to 10 carbon atoms and / or by a partly or fully deuterated, branched or linear alkyl group having 1 to 10 carbon atoms. 5 In emitters of the formula (I), n is preferably 1 and m is preferably 2. In emitters of the formula (I), preferably, one X is selected from N and the other X are CR, or all X are the same or different at each instance and are CR. In emitters of the formula (I), at least one R is preferably different from H. In emitters of the formula (I), preferably two R are different from H and have one of the other 10 definitions given above for the emitters of the formula (I). The invention accordingly further provides an organic electroluminescent device as described above or described as preferred, characterized in that the light-emitting layer, as well as the mixed host system, comprises at least one phosphorescent emitter 15 conforming to the formula (I). Particularly preferred examples of phosphorescent emitters are listed in table 8 below. Table 8: 20 25 30 35 P25-014 SC - 145 - 5 10 15 20 25 30 35 P25-014 SC - 146 - 5 In the mixed host system of the invention or in the light-emitting layer of the device of the invention, any mixture as described preferably a combination of E1 to E66 with H1 to 10 H42 and with H2-1 to H2-47, particularly selected from M1 to M1000, is preferably combined with a compound of the formula (I) or a compound from table 8. The light-emitting layer in the organic electroluminescent device of the invention, comprising at least one phosphorescent emitter, is preferably an infrared-emitting or 15 yellow-, orange-, red-, green-, blue- or ultraviolet-emitting layer, more preferably a yellow- or green-emitting layer and most preferably a green-emitting layer. A yellow-emitting layer is understood here to mean a layer having a photoluminescence maximum within the range from 540 to 570 nm. An orange-emitting layer is understood 20 to mean a layer having a photoluminescence maximum within the range from 570 to 600 nm. A red-emitting layer is understood to mean a layer having a photoluminescence maximum within the range from 600 to 750 nm. A green-emitting layer is understood to mean a layer having a photoluminescence maximum within the range from 490 to 540 nm. A blue-emitting layer is understood to mean a layer having a 25 photoluminescence maximum within the range from 440 to 490 nm. The photoluminescence maximum of the layer is determined here by measuring the photoluminescence spectrum of the layer having a layer thickness of 50 nm at room temperature, where the layer comprises the inventive combination of the host materials as described before or preferably described before, and the corresponding emitter. 30 The photoluminescence spectrum of the layer is recorded, for example, with a commercial photoluminescence spectrometer. The photoluminescence spectrum of the emitter chosen is generally measured in 35 oxygen-free solution, 10-5molar, at room temperature, a suitable solvent being any in which the chosen emitter dissolves in the concentration mentioned. Particularly suitable solvents are typically toluene or 2-methyl-THF, but also dichloromethane. Measurement is effected with a commercial photoluminescence spectrometer. The triplet energy T1 in P25-014 SC - 147 - eV is determined from the photoluminescence spectra of the emitters. First the peak maximum Plmax. (in nm) of the photoluminescence spectrum is determined. The peak maximum Plmax. (in nm) is then converted to eV by: E(T1in eV) = 1240 / E(T1in nm) = 1240 / PLmax. (in nm). 5 Preferred phosphorescent emitters are accordingly yellow emitters, preferably of the formula (I) or from table 8, the triplet energy T1 of which is preferably ~2.3 eV to ~2.1 eV. Preferred phosphorescent emitters are accordingly green emitters, preferably of the 10 formula (I) or from table 8, the triplet energy T1 of which is preferably ~2.5 eV to ~2.3 eV. Particularly preferred phosphorescent emitters are accordingly green emitters, preferably of the formula (I) or from table 8 as described above, the triplet energy T1 of which is preferably ~2.5 eV to ~2.3 eV. 15 Most preferably, green emitters, preferably of the formula (I) or from table 8, as described above, are selected for the mixture of the invention or emitting layer of the invention. 20 It is also possible for fluorescent emitters to be present in the light-emitting layer of the device of the invention or in the mixture of the invention. Preferred fluorescent emitting compounds are selected from the class of the arylamines, where preferably at least one of the aromatic or heteroaromatic ring systems of the arylamine is a fused ring system, more preferably having at least 14 ring atoms. 25 Preferred examples of these are aromatic anthraceneamines, aromatic anthracenediamines, aromatic pyreneamines, aromatic pyrenediamines, aromatic chryseneamines or aromatic chrysenediamines. An aromatic anthraceneamine is understood to mean a compound in which a diarylamino group is bonded directly to an anthracene group, preferably in the 9 position. An aromatic anthracenediamine is 30 understood to mean a compound in which two diarylamino groups are bonded directly to an anthracene group, preferably in the 9,10 positions. Aromatic pyreneamines, pyrenediamines, chryseneamines and chrysenediamines are defined analogously, where the diarylamino groups are bonded to the pyrene preferably in the 1 position or 1,6 positions. Further preferred emitting compounds are indenofluoreneamines or - 35 diamines, benzoindenofluoreneamines or -diamines, and dibenzoindenofluoreneamines or -diamines, and indenofluorene derivatives having fused aryl groups. Likewise preferred are pyrenearylamines. Likewise preferred are benzoindenofluoreneamines, benzofluoreneamines, extended benzoindenofluorenes, phenoxazines, and fluorene derivatives joined to furan units or to thiophene units. The light-emitting device or the P25-014 SC - 148 - mixed host system of the invention may additionally also comprise materials that exhibit TADF (thermally activated delayed fluorescence). Correspondingly, the light-emitting layer in the device of the invention preferably contains 5 between 1% and 30% by volume, more preferably between 2% and 20% by volume, most preferably between 3% and 10% by volume, of the emitter based on the overall composition of the light-emitting layer composed of emitter and the mixed host system according to the invention. If the compounds are processed from solution, preference is given to using the corresponding amounts in % by weight rather than the above- 10 specified amounts in % by volume. Preferably, the compounds are deposited by evaporation in vacuum. The present invention also relates to an organic electroluminescent device as described above or described as preferred, wherein the organic layer comprises a hole injection 15 layer (HIL) and / or a hole transport layer (HTL) and / or an electron blocking layer (EBL), the hole-injecting material and / or hole-transporting material and / or electron blocking layer of which belongs to the class of monoamines or diamines that do not contain a carbazole unit. The hole-injecting material and / or hole-transporting material and / or electron blocking material particularly preferably comprises a monoamine or diamine 20 containing a fluorenyl or bispirofluorenyl group, but no carbazole unit. The hole-injecting material and / or hole-transporting material and / or electron blocking material particularly preferably comprises a monoamine containing a fluorenyl or bispirofluorenyl group, but no carbazole unit. 25 The sequence of layers in the organic electroluminescent device of the invention is preferably as follows: anode / hole injection layer / hole transport layer / emitting layer / hole blocker layer / electron transport layer / electron injection layer / cathode. 30 This sequence of the layers is a preferred sequence. At the same time, it should be pointed out again that not all the layers mentioned need be present and / or that further layers may additionally be present. Materials used for the electron transport layer may be any materials as used according 35 to the prior art as electron transport materials in the electron transport layer. Especially suitable are aluminum complexes, for example Alq3, zirconium complexes, for example Zrq4, benzimidazole derivatives, triazine derivatives, pyrimidine derivatives, pyridine derivatives, pyrazine derivatives, quinoxaline derivatives, quinoline derivatives, P25-014 SC - 149 - oxadiazole derivatives, aromatic ketones, lactams, boranes, diazaphosphole derivatives and phosphine oxide derivatives. Suitable cathodes of the device of the invention are metals having a low work function, 5 metal alloys or multilayer structures composed of various metals, for example alkaline earth metals, alkali metals, main group metals or lanthanoids (e.g. Ca, Ba, Mg, Al, In, Yb, Sm, etc.). Additionally suitable are alloys composed of an alkali metal or alkaline earth metal and silver, for example an alloy composed of magnesium and silver. In the case of multilayer structures, in addition to the metals mentioned, it is also possible to 10 use further metals having a relatively high work function, for example Ag or Al, in which case combinations of the metals such as Ca / Ag, Mg / Ag or Ba / Ag, for example, are generally used. It may also be preferable to introduce a thin interlayer of a material having a high dielectric constant between a metallic cathode and the organic semiconductor. Examples of useful materials for this purpose are alkali metal or alkaline 15 earth metal fluorides, but also the corresponding oxides or carbonates (e.g. LiF, Li2O, BaF2, MgO, NaF, CsF, Cs2CO3, etc.). It is also possible to use lithium quinolinate (LiQ) for this purpose. The layer thickness of this layer is preferably between 0.5 and 5 nm. Preferred anodes are materials having a high work function. Preferably, the anode has a 20 work function of greater than 4.5 eV versus vacuum. Firstly, metals having a high redox potential are suitable for this purpose, for example Ag, Pt or Au. Secondly, metal / metal oxide electrodes (e.g. Al / Ni / NiOx, Al / PtOx) may also be preferred. For some applications, at least one of the electrodes has to be transparent or partly transparent in order to enable either the irradiation of the organic material (organic solar cell) or the emission of 25 light (OLED, O-LASER). Preferred anode materials here are conductive mixed metal oxides. Particular preference is given to indium tin oxide (ITO) or indium zinc oxide (IZO). Preference is further given to conductive doped organic materials, especially conductive doped polymers. In addition, the anode may also consist of two or more layers, for example of an inner layer of ITO and an outer layer of a metal oxide, 30 preferably tungsten oxide, molybdenum oxide or vanadium oxide. The organic electroluminescent device of the invention, in the course of production, is appropriately (according to the application) structured, contact-connected and finally sealed, since the lifetime of the devices of the invention is shortened in the presence of 35 water and / or air. The production of the device of the invention is not restricted here. It is possible that one or more organic layers, including the light-emitting layer, are coated by a sublimation method. In this case, the materials are applied by vapor deposition in vacuum P25-014 SC - 150 - sublimation systems at an initial pressure of less than 10-5mbar, preferably less than 10- 6mbar. In this case, however, it is also possible that the initial pressure is even lower, for example less than 10-7mbar. 5 The organic electroluminescent device of the invention is preferably characterized in that one or more layers are coated by the OVPD (organic vapor phase deposition) method or with the aid of a carrier gas sublimation. In this case, the materials are applied at a pressure between 10-5mbar and 1 bar. A special case of this method is the OVJP (organic vapor jet printing) method, in which the materials are applied directly by a 10 nozzle and thus structured. In the case of production by means of gas phase deposition, there are in principle two ways in which the organic layer, preferably the light-emitting layer, of the invention can be applied or vapor-deposited onto any substrate or the prior layer. Firstly, the materials 15 used can each be initially charged in a material source and ultimately evaporated from the different material sources ("co-evaporation"). Secondly, the various materials can be premixed (premix systems) and the mixture can be initially charged in a single material source from which it is ultimately evaporated ("premix evaporation"). In this way, it is possible in a simple and rapid manner to achieve the vapor deposition of the light- 20 emitting layer with homogeneous distribution of the components without the need for precise actuation of a multitude of material sources. The following methods are possible: A process for producing the organic electroluminescent device of the invention as 25 described above or described as preferred, characterized in that the at least one light- emitting layer is applied by gas phase deposition, especially by a sublimation method and / or by an OVPD (organic vapor phase deposition) method and / or with the aid of a carrier gas sublimation. 30 A process for producing the organic electroluminescent device of the invention, as described above or described as preferred, characterized in that the light-emitting layer is applied by gas phase deposition, wherein the e-TMM, the h-TMM1 and the h-TMM2 is deposited from the gas phase together with further materials that form the light-emitting layer, successively or simultaneously from at least three material sources. 35 A process for producing the device of the invention, characterized in that the light- emitting layer is applied by gas phase deposition, wherein the e-TMM and h-TMM1, or the e-TMM and h-TMM2, or the h-TMM1 and the h-TMM2, or the e-TMM and h-TMM1 and h-TMM2, are deposited from the gas phase together as premix, successively or P25-014 SC - 151 - simultaneously with the light-emitting materials selected from the group of the phosphorescent emitters, fluorescent emitters and / or emitters that exhibit TADF (thermally activated delayed fluorescence). 5 The electronic devices of the invention, especially organic electroluminescent devices, are notable for one or more of the following surprising advantages over the prior art: 1. The capacitance properties of organic light-emitting devices comprising the mixed host system or the preferred embodiments recited above and hereinafter, can be 10 tuned with respect to the operating voltage of the onset of the capacitance curve (beyond the level of the geometric capacitance) and / or the maximum capacitance signal. This is advantageous for enabling high refresh rates when used as an electroluminescent device in screens. 15 These abovementioned advantages are not accompanied by an inordinately high deterioration in the further electronic properties. It should be pointed out that variations of the embodiments described in the present invention are covered by the scope of this invention. Any feature disclosed in the present 20 invention may, unless this is explicitly ruled out, be exchanged for alternative features which serve the same purpose or an equivalent or similar purpose. Any feature disclosed in the present invention, unless stated otherwise, should therefore be considered as an example from a generic series or as an equivalent or similar feature. 25 All features of the present invention may be combined with one another in any manner, unless particular features and / or steps are mutually exclusive. This is especially true of preferred features of the present invention. Equally, features of non-essential combinations may be used separately (and not in combination). 30 The technical teaching disclosed with the present invention may be abstracted and combined with other examples. The invention is illustrated in detail by the examples which follow, without any intention of restricting it thereby. 35 Examples Synthesis examples The syntheses which follow, unless stated otherwise, are conducted under a protective gas atmosphere in dried solvents. The compounds of the invention can be prepared by means of synthesis methods known to those skilled in the art. P25-014 SC - 152 - 1) 5-([1,1'-biphenyl]-3-yl)-8-(triphenylen-1-yl)-5,8-dihydroindolo[2,3-c] carbazole 5 10 25 g (61 mmol; 1.00 eq.) of 5-([1,1'-biphenyl]-3-yl)-5,8-dihydroindolo[2,3-c]carbazole, 20.6 g (67 mmol; 1.1 eq.) of 1-bromotriphenylene and 7.4 g (67 mmol; 1.10 eq.) of sodium tert-pentoxide in 200 ml of toluene is inertized in an argon stream for 30 minutes. Then 738 mg (1.8 mmol; 3 mol%) of dicyclohexyl-(2',6'-dimethoxybiphenyl-2- yl)phosphane (SPhos), 403 mg (1.8 mmol; 3 mol%) of palladium acetate are added and 15 the mixture is heated to reflux for 18 hours. After completion of conversion and cooling to room temperature, 500 ml of water are added to the reaction. After separation of the phases and extraction of the aqueous phase with toluene, the combined organic phases are concentrated and heptane is added. The precipitated solids are isolated. Purification by means of Soxhlet extraction, recrystallization and vacuum sublimation gives the 20 desired product (23.2 g; 36.6 mmol; 60% of theory). The following compounds can be obtained analogously with a yield between 40 and 80%: 25 2) 2-[4-[9-(4,6-Diphenyl-1,3,5-triazin-2-yl)dibenzofuran-2-yl]phenyl]-4,6-diphenyl- 30 35 68.7 g (110.0 mmol) of 2.4-diphenyl-6-[g-(4,4,5, 5-tetramethyl-1,3,2-dioxaborolan-2- yl)dibenzofurane-1-yl]- 1,3,5-triazine, 42 g (110.0 mmol) of 2-(4-bromophenyl)-4, 6- diphenyl-1,3,5-triazine and 21 g (210.0 mmol) of sodium carbonate are suspended in 500 ml of ethylene glycol diamine ether and 500 ml of stater.913 mg (3,0 mmol) of P25-014 SC - 153 - tri-o-tolylphosphine and then 112 m (0,5 mmol) of palladium(II)acetate arc added to tins suspension, and the reaction mixture is heated under reflux for 16 h. After cooling, the organic phase is separated off, filtered through silica gel, washed three times with 200 ml of water and subsequently evaporated to dryness The product is purified by column 5 chromatography on silica gel with toluene / CHCl3 (1:1) and finally sublimed in a high vacuum (p=5x 10 mbar) (punty 99.9%). The yield is 64 g (81 mmol). corresponding to 70% of theory. The following compound can be prepared analogously. 10 15 3) 4-(dibenzo[b,d]furan-1-yl)-11-(4,6-diphenyl-1,3,5-triazin-2-yl)-2-phenyl-11H- 20 pyrimido[4',5':4,5]furo[3,2-b]carbazole 25 31.3 g (62.5 mmol) of 4-(dibenzo[b,d]furan-1-yl)-2-phenyl-11H-pyrimido[4',5':4,5]furo[3,2- b]carbazole dissolved in 200 ml of dimethylformamide under a protective gas 30 atmosphere, and 7.7 g of NaH, 60% in mineral oil, (194 mmol is added After 1 h at room temperature, a solution of 2-chlore-4,6-diphenyl-[1,3.5]-triazine (25 g, 68 mmol) in 300 ml of dimethylformamide is added dropwise. The reaction mixture is then stirred at room temperature for 12 h. After this time, the reaction mixture is poured onto ice and extracted three times with dichloromethane. The combined organic phases are dried 35 over NasSO3and concentrated. The residue is subjected to hot extraction (with toluene and recrystallized from dichloromethane / isopropanol and finally sublimed under high vacuum: punty is 99.9%. The yield is 24 g (32 mmol), corresponding to 52% of theory. P25-014 SC - 154 - The following compound can be prepared analogously. 5 10 GSPS values of the described materials. The values are determined according to the procedure specified in the description. 15 Table: GSPS of selected hosts 20 25 30 35 Part 1: Fabrication of vapor processed OLED devices The use of the material combinations according to the invention in OLEDs is presented in the following examples E1-1 to E18-3 the corresponding reference examples are P25-014 SC - 155 - given as C1-1 to C18-2 (see Tables 9 and 10). For bottom emission (BE) devices types (emission through the ITO anode) glass plaques coated with a structured ITO (indium tin oxide) anode of thickness 50 nm are treated with 5 an oxygen plasma, followed by an argon plasma. These plasma treated glass plaques form the substrates to which the OLEDs layers are applied. For top emission (TE) device types the glass plaques are coated with three layers in the following order: ITO 40nm / Silver 30nm / ITO 20nm. The OLEDs basically have the following layer structure: substrate / hole injection layer 10 (HIL) / hole transport layer (HTL) / electron blocking layer (EBL) / emission layer (EML) / hole blocking layer (HBL) / electron transport layer (ETL) / electron injection layer (EIL) and finally a cathode. For BE devices the cathode is formed by two thermally evaporated layers in the following order: Ytterbium 1.5nm / Aluminium 100nm. For TE devices devices the cathode is formed by three thermally evaporated layers: Ytterbium 1.5nm / 15 Silver:Magnesium (90:10 vol%) 15nm / SpMA185nm. The detailed stack sequence with respect to the purely organic layers is shown in table 9. The materials used for the OLED fabrication are presented in table 11, unless previously described. The performance data of the OLEDs are summarized in table 10. 20 The GSP slopes (GSPS) of the various hosts are given in the table as described before. All materials are applied by thermal vapour deposition in a vacuum chamber. The emission layer here always consists of at least one matrix material and one emitting 25 dopant, which is mixed with the matrix material or matrix materials in a certain proportion by volume by co-evaporation. An expression such as E2:H2-3:H5:TEG2 (36%:40%:14%:10%) here means that material E2 is present in the layer in a proportion by volume of 36%, material H2-3 is present in the layer in a proportion by volume of 40%, material H5 is present in the layer in a proportion by volume of 14% and material 30 TEG2 is present in the layer in a proportion by volume of 10%. Analogously, the electron-transport layer and hole-injection layer may also consist of a mixture of two or more materials. The OLED devices are characterized by standard methods. For this purpose, 35 electroluminescence spectra and current-voltage-luminance (IVL) characteristics are measured, from which the external quantum efficiency (EQE) is calculated. The calculation is performed assuming Lambertian emission characteristics. EQE10 and U10 denote the external quantum efficiency (EQE) and device driving voltage ((U) measured at a current density of 10 mA / cm². P25-014 SC - 156 - The lifetime LT is defined as the time in hours (h) after which the luminance drops from the starting luminance (L0) in cd / m² to a certain luminance L1 in cd / m² in the course of operation with constant current j0. A figure of L1 / L0=90% means that the lifetime 5 reported in the LT column corresponds to the time after which the starting luminance (L0) falls to 90% of its starting value. The capacitance C in nF of the device is determined via dielectric spectroscopy measurements using an Alpha-NB Single-Unit Dielectric Analyzer (Novocontrol 10 technologies) combined with a dielectric interface (Novocontrol ZGS). This setup allows frequency sweeps covering a range from f = 10−2to f = 107Hz. The AC rms voltage UAC is set to 100 mV for all measurements and the superimposed DC bias UDC is varied between -7 and 7 V at a frequency f in Hz. The experimental capacity C-f-UDC curves are analyzed according to the theoretical description in J. Appl. Phys.107, 1–9 (2010). The 15 onset voltage Von,cap in V is defined as the point within the C(V) curve, where the curve significantly leaves the geometrical capacitance Cg for the first time and is determined as the intersection of the geometrical capacitance baseline and the tangent of the low voltage flank of the capacitance peak. The determination of Von,cap is also shown schematically in Figure 1. 20 Part 2: Use of mixtures according to the invention in OLEDs The material combinations according to the invention can be used in the emission layer in phosphorescent green OLEDs. As can be seen from Table 9 and Table 10, combinations of two h-TMMs and adjustment of the ratio between these two h-TMMs in 25 the light-emitting layer, allows to precisely tune the capacitance characteristics (Von,cap) of the prepared OLEDs. At the same time, the prepared devices show good lifetime and high efficiency. This is confirmed by the results in Table 10 for the combination of different pairs of hTMMs with different e-TMMs and with two different emitters. 30 Table 9: OLED stack 35 P25-014 SC - 157 - 5 10 15 20 25 30 35 P25-014 SC - 158 - 5 10 15 20 25 30 35 P25-014 SC - 159 - 5 10 15 20 25 30 35 P25-014 SC - 160 - 5 10 15 20 25 30 35 P25-014 SC - 161 - 5 10 15 20 25 30 35 P25-014 SC - 162 - SpMA5:PD1 - Ey3D:H2-6:H7:TEG1 AT1 ST1:LiQ LiQ E17- SpMA5 SpMA6 (97%:3%) (32%:30%:30%:8%) 5 (50%:50%) 1 2 70 nm 10 nm 10 nm 40 nm nm 30 nm nm SpMA5:PD1 - Ey3D:H2-6:H7:TEG1 AT1 ST1:LiQ LiQ E17- SpMA5 SpMA6 (97%:3%) (32%:45%:15%:8%) 5 (50%:50%) 1 3 70 nm 10 nm 5 10 nm 40 nm nm 30 nm nm SpMA5:PD1 - E5D:H1:TEG1 AT1 ST1:LiQ LiQ C18- SpMA5 SpMA6 (97%:3%) (32%:60%:8%) 5 (50%:50%) 1 1 70 nm 10 nm 10 nm 40 nm nm 30 nm nm SpMA5:PD1 - E5D:H2x2:TEG1 AT1 ST1:LiQ LiQ C18- SpMA5 SpMA6 (97%:3%) (32%:60%:8%) 5 (50%:50%) 1 2 70 nm 10 nm 10 nm 40 nm nm 30 nm nm 10 SpMA5:PD1 - E5D:H2x2:H7:TEG1 AT1 ST1:LiQ LiQ E18- SpMA5 SpMA6 (97%:3%) (32%:15%:45%:8%) 5 (50%:50%) 1 1 70 nm 10 nm 10 nm 40 nm nm 30 nm nm SpMA5:PD1 - E5D:H2x2:H7:TEG1 AT1 ST1:LiQ LiQ E18- SpMA5 SpMA6 (97%:3%) (32%:30%:30%:8%) 5 (50%:50%) 1 2 70 nm 10 nm 10 nm 40 nm nm 30 nm nm 15 SpMA5:PD1 - E5D:H2x2:H7:TEG1 AT1 ST1:LiQ LiQ E18- SpMA5 SpMA6 (97%:3%) (32%:45%:15%:8%) 5 (50%:50%) 1 3 70 nm 10 nm 10 nm 40 nm nm 30 nm nm Table 10: OLED performance 20 25 30 35 P25-014 SC - 163 - 5 10 15 20 25 30 35 P25-014 SC - 164 - 5 10 15 Table 11: Materials used, if not already described 20 25 30 35 P25-014 SC - 165 - P25-014 SC - 166 - 5 10 15 20 25 30 35 P25-014 SC - 167 - 5 10 15 20 25 The following host systems e-TMM, h-TMM1 and h-TMM2 in table 12 further support the invention when used in a light-emitting layer of an organic light-emitting device: Table 12: 30 35 P25-014 SC - 168 - 5 10 15 20 25 List of figures Figure 1: Determination of Von,cap (1) from the capacitance-voltage plot 30 35

Claims

1. P25-014 SC - 169 - Claims 1. An organic light-emitting device comprising an anode, a cathode, arranged opposite to the anode; and at least one light-emtting layer arranged between the anode and 5 cathode, wherein the at least one light-emitting layer comprises a mixed host system comprising at least three components, where the first component is an electron- transporting host material e-TMM, the second component is a first hole-transporting host material h-TMM1, the third component is a second hole-transporting host 10 material h-TMM2 which is different from h-TMM1, the optional further component is capable of being a host material, wherein the first hole-transporting host material h-TMM1 exhibits a giant surface potential slope (GSP-slope) GSPSH1 when deposited by evaporation in vacuum as an organic film on an ITO covered glas substrate and measured by Kelvin probe, 15 wherein the second hole-transporting host material h-TMM2 exhibits a GSP-slope GSPSH2 when deposited by evaporation in vacuum as an organic film on an ITO covered glas substrate and measured by Kelvin probe, wherein the absolute value of the difference between GSPSH1 and GSPSH2 is greater than 30 mV / nm. 20 2. An organic light-emitting device according to Claim 1 wherein the absolute value of the difference between GSPSH1 and GSPSH2 is greater than 37.5 mV / nm.

3. An organic light-emitting device according to Claim 1 wherein the absolute value of 25 the difference between GSPSH1 and GSPSH2 is greater than 45 mV / nm.

4. An organic light-emitting device according to one or more of Claims 1 to 3, where at least one of the GSP-slopes GSPSH1 and GSPSH2 is smaller than 0 mV / nm. 30 5. An organic light-emitting device according to one or more of Claims 1 to 4, where one of the GSP-slopes GSPSH1 and GSPSH2 is smaller than 0 mV / nm and the other is greater than 0 mV / nm.

6. An organic light-emitting device according to any one of Claims 1 to 5 wherein the first hole-transporting host material h-TMM1 comprise a structural element of 35 formula (A) P25-014 SC - 170 - 5 , where * indicates the binding site to the remainder of the material h-TMM1; R is the same or different at each instance and is D, F, CN, or an aryl group 10 having 6 to 40 carbon atoms or a heteroaryl group having 5 to 40 ring atoms which may both be partially or fully deuterated; a, b at each instance are independently 0, 1, 2, 3 or 4; and c is 0, 1, 2 or 3. 15 7. An organic light-emitting device according to Claim 6 where the remainder of the first hole-transport material h-TMM1 corresponds to one of the formulae (1a) to (1g), 20 25 30 35 P25-014 SC - 171 - 5 10 15 20 25 30 35 # indicates the binding site to formula (A) marked with *; P25-014 SC - 172 - Ar5 is the same or different at each instance and is an aromatic or heteroaromatic ring system which has 5 to 40 ring atoms and may be substituted by one or more R7radicals; R6at each instance is the same or different and is D, F, CN, a straight-chain alkyl 5 group having 1 to 20 carbon atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, where the alkyl, alkenyl or alkynyl group may in each case be substituted by one or more R7radicals and where one or more nonadjacent CH2 groups may be replaced by Si(H)2, Si(R7)2, C=O, NH, NR7, O, S, CONH or CONR7, or an 10 aromatic or heteroaromatic ring system which has 5 to 60 ring atoms and which may be partially or completely deuterated in each case; it is also possible here for two R6radicals together to form an aromatic, heteroaromatic, aliphatic, or heteroaliphatic ring system; R7is the same or different at each instance and is D, F, Cl, Br, I, N(R8)2, CN, NO2, 15 OR8, SR8, Si(R8)3, B(OR8)2, C(=O)R8, P(=O)(R8)2, S(=O)R8, S(=O)2R8, OSO2R8, a straight-chain alkyl group having 1 to 20 carbon atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, where the alkyl, alkenyl or alkynyl group may in each case be substituted by one or more R8radicals and where one or more 20 nonadjacent CH2 groups may be replaced by Si(R8)2, C=O, NR8, O, S or CONR8, or an aromatic or heteroaromatic ring system which has 5 to 40 ring atoms and which may be partially or completely deuterated in each case; at the same time, two or more R7radicals together may form an aromatic, heteroaromatic, aliphatic or heteroaliphatic ring system; 25 R8is the same or different at each instance and is H, D, F or an aliphatic, aromatic or heteroaromatic organic radical, especially a hydrocarbyl radical, having 1 to 20 carbon atoms, in which one or more hydrogen atoms may also be replaced by F; s is the same or different at each instance and is 0, 1, 2, 3 or 4; 30 t is the same or different at each instance and is 0, 1, 2 or 3; and u is the same or different at each instance and is 0, 1 or 2.

8. An organic light-emitting device according to any one of Claims 1 to 7, where the second hole-transport material h-TMM2 is selected from the group consisting of 35 dibenzofuran substituted carbazoles, diarylamino substituted carbazoles, dibenzothiophenes having at least one triphenylene substituent, anthracenes, biscarbazoles, indolocarbazoles, and indolo[3,2,1-JK]carbazoles. P25-014 SC - 173 - 9. An organic light-emitting device according to any one of Claims 1 to 8, where the electron-transporting host material e-TMM is selected from the group consisting of pyrimidines, triazines, diazadibenzofurans, diazadibenzothiophenes, quinazolines, benzo[h]quinazolines and quinoxalines. 5 10. An organic light-emitting device device according to any one of Claims 1 to 9, characterized in that it is an electroluminescent device selected from organic light- emitting transistors (OLETs), organic field quench devices (OFQDs), organic light- emitting electrochemical cells (OLECs), organic laser diodes (O-lasers) and organic 10 light-emitting diodes (OLEDs).

11. An organic light-emitting device according to any one of Claims 1 to 10, wherein in addition to the light-emitting layer (EML), a hole injection layer (HIL), a hole transport layer (HTL), an electron blocking layer (EBL), an electron transport layer (ETL), an 15 electron injection layer (EIL) and / or a hole blocker layer (HBL) and / or an exciton blocking layer and / or charge generation layers.

12. A mixed host system comprising at least three components, where the first component is an electron-transporting host material e-TMM, the second component 20 is a first hole-transporting host material h-TMM1, the third component is a second hole-transporting host material h-TMM2 which is different from h-TMM1, the optional further component is capable of being a host material, wherein the first hole-transporting host material h-TMM1 exhibits a giant surface potential slope (GSP-slope) GSPSH1when deposited by evaporation in vacuum as 25 an organic film on an ITO covered glas substrate and measured by Kelvin probe, wherein the second hole-transporting host material h-TMM2 exhibits a GSP-slope GSPSH2when deposited by evaporation in vacuum as an organic film on an ITO covered glas substrate and measured by Kelvin probe, wherein the absolute value of the difference between GSPSH1and GSPSH2is greater 30 than 30 mV / nm.

13. A mixed host system according to Claim 12 wherein the first hole-transport material h-TMM1 corresponds to one of the formulae (1A) to (1G), 35 P25-014 SC - 174 - P25-014 SC - 175 - 5 10 15 20 25 30 35 P25-014 SC - 176 - 5 10 formula (1G), where R is the same or different at each instance and is D, F, CN, or an aryl group having 6 to 40 carbon atoms or a heteroaryl group having 5 to 40 ring atoms 15 which may both be partially or fully deuterated; a, b at each instance are independently 0, 1, 2, 3 or 4; and c is 0, 1, 2 or 3. Ar5 is the same or different at each instance and is an aromatic or heteroaromatic ring system which has 5 to 40 ring atoms and may be substituted by one or 20 more R7radicals; R6at each instance is the same or different and is D, F, CN, a straight-chain alkyl group having 1 to 20 carbon atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, where the alkyl, alkenyl or alkynyl group may in each case be substituted by 25 one or more R7radicals and where one or more nonadjacent CH2groups may be replaced by Si(H)2, Si(R7)2, C=O, NH, NR7, O, S, CONH or CONR7, or an aromatic or heteroaromatic ring system which has 5 to 60 ring atoms and which may be partially or completely deuterated in each case; it is also possible here for two R6radicals together to form an aromatic, heteroaromatic, aliphatic, or 30 heteroaliphatic ring system; R7is the same or different at each instance and is D, F, Cl, Br, I, N(R8)2, CN, NO2, OR8, SR8, Si(R8)3, B(OR8)2, C(=O)R8, P(=O)(R8)2, S(=O)R8, S(=O)2R8, OSO2R8, a straight-chain alkyl group having 1 to 20 carbon atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkyl group 35 having 3 to 20 carbon atoms, where the alkyl, alkenyl or alkynyl group may in each case be substituted by one or more R8radicals and where one or more nonadjacent CH2groups may be replaced by Si(R8)2, C=O, NR8, O, S or CONR8, or an aromatic or heteroaromatic ring system which has 5 to 40 ring P25-014 SC - 177 - atoms and which may be partially or completely deuterated in each case; at the same time, two or more R7radicals together may form an aromatic, heteroaromatic, aliphatic or heteroaliphatic ring system; R8is the same or different at each instance and is H, D, F or an aliphatic, aromatic 5 or heteroaromatic organic radical, especially a hydrocarbyl radical, having 1 to 20 carbon atoms, in which one or more hydrogen atoms may also be replaced by F; s is the same or different at each instance and is 0, 1, 2, 3 or 4; t is the same or different at each instance and is 0, 1, 2 or 3; and 10 u is the same or different at each instance and is 0, 1 or 2.

14. A mixed host system according to Claims 12 or 13 wherein the 2nd hole-transport material h-TMM2 corresponds to one of the formulae (2A), (2B) and (2C), 15 20 25 30 35 P25-014 SC - 178 - where the symbols and indices Ar5, R6, s, t and u have a meaning according to Claim 13, but Ar5 does not contain the structural formula (A) as described in claim 6.

15. A mixed host system according to Claims 12, 13 or 14, wherein the electron- 5 transporting host material e-TMM corresponds to one of formulae (3A), (3B), (3C), 10 15 20 25 30 35 , where X stands on each occurrence, identically or differently, for N or CR12, preferably for N; P25-014 SC - 179 - L2is the same or different at each instance and is a single bond or an aromatic or heteroaromatic ring system which has 5 to 24 ring atoms and may be substituted in each case by one or more R11radicals; R## is the same or different instance and is D, F, CN, a straight-chain alkyl group 5 having 1 to 20 carbon atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, where the alkyl, alkenyl or alkynyl group may in each case be substituted by one or more R11radicals or an aromatic ring system which has 6 to 24 ring atoms and may be substituted by one or more R11radicals, 10 and two adjacent substituents R## together may form an aromatic, heteroaromatic, aliphatic, heteroaliphatic ring system that may be substituted by one or more R11radicals; Y is the same or different at each instance and is N or CR9, with exclusion of the possibility that two Y alongside one another are both N; 15 V2is O or S; R8is the same or different at each instance and is H, D, F or an aliphatic, aromatic or heteroaromatic organic radical, especially a hydrocarbyl radical, having 1 to 20 carbon atoms, in which one or more hydrogen atoms may also be replaced by F; 20 R9is the same or different at each instance and is H, D, F, Cl, Br, I, N(R8)2, CN, NO2, OR8, SR8, Si(R8)3, B(OR8)2, C(=O)R8, P(=O)(R8)2, S(=O)R8, S(=O)2R8, OSO2R8, a straight-chain alkyl group having 1 to 20 carbon atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, where the alkyl, alkenyl or alkynyl 25 group may in each case be substituted by one or more R12radicals and where one or more nonadjacent CH2 groups may be replaced by Si(R8)2, C=O, NR8, O, S or CONR8, or an aromatic or heteroaromatic ring system which has 5 to 40 ring atoms and may be substituted in each case by one or more R12radicals; at the same time, two or more R9radicals together may 30 form an aromatic, heteroaromatic, aliphatic or heteroaliphatic ring system; R11is the same or different at each instance and is D, F, Cl, Br, I, N(R8)2, CN, NO2, OR8, SR8, Si(R8)3, B(OR8)2, C(=O)R8, P(=O)(R8)2, S(=O)R8, S(=O)2R8, OSO2R8, a straight-chain alkyl group having 1 to 20 carbon atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic 35 alkyl group having 3 to 20 carbon atoms, where the alkyl, alkenyl or alkynyl group may in each case be substituted by one or more R8radicals and where one or more nonadjacent CH2 groups may be replaced by Si(R8)2, C=O, NR8, O, S or CONR8, or an aromatic or heteroaromatic ring system which has 5 to 40 ring atoms and which may be partially or completely P25-014 SC - 180 - deuterated in each case; at the same time, two or more R11radicals together may form an aromatic, heteroaromatic, aliphatic or heteroaliphatic ring system; R12at each instance is the same or different and is D, F, CN, a straight-chain 5 alkyl group having 1 to 20 carbon atoms or an alkenyl or alkynyl group having 2 to 20 carbon atoms or a branched or cyclic alkyl group having 3 to 20 carbon atoms, where the alkyl, alkenyl or alkynyl group may in each case be substituted by one or more R11radicals and where one or more nonadjacent CH2 groups may be replaced by Si(H)2, Si(R11)2, C=O, NH, 10 NR11, O, S, CONH or CONR11, or an aromatic or heteroaromatic ring system which has 5 to 60 ring atoms and which may be partially or completely deuterated in each case; it is also possible here for two R12radicals together to form an aromatic, heteroaromatic, aliphatic, or heteroaliphatic ring system; Ar6 is the same or different at each instance and is an aromatic or 15 heteroaromatic ring system which has 5 to 40 ring atoms and may be substituted by one or more R11radicals; b1 is 0, 1, 2, 3, or 4; b2 is 0, 1, 2, or 3. 20 25 30 35

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