Electroluminescent Devices

Abstract

The present invention describes electronic devices and compositions that can be used in electronic devices.

Description

[Technical field]

[0001] The present invention relates to organic electroluminescent devices and compositions comprising various organic functional materials.

[0002] The structures of organic electroluminescent devices, especially OLEDs (organic light-emitting diodes), in which organic semiconductors are used as functional materials, are described, for example, in US4539507, US5151629, EP0676461 and WO98 / 27136. The emitting materials used are often organometallic complexes that exhibit phosphorescence, and fluorescent emitters. For quantum mechanical reasons, the use of organometallic compounds as phosphorescent emitters allows up to four times the energy and power efficiency. In general terms, there is still a need for improvements in OLEDs, especially in OLEDs that exhibit phosphorescence, for example in terms of efficiency, operating voltage and lifetime. Organic electroluminescent devices that include fluorescent emitters or emitters that exhibit TADF (thermally activated delayed fluorescence) are also known.

[0003] The properties of organic electroluminescent devices are not only determined by the emitter used. Other materials used, such as host / matrix materials, hole blocking materials, electron transport materials, hole transport materials, and electron or exciton blocking materials, are also of particular importance here. Improvements in these materials can lead to obvious improvements in electroluminescent devices.

[0004] According to the prior art, there are various approaches to further improve the performance data of organic electroluminescent devices. WO2015 / 091716A1 and WO2016 / 193243A1 disclose OLEDs that contain both phosphorescent compounds and fluorescent emitters in the emitting layer, and energy is transferred from the phosphorescent compounds to the fluorescent emitters. In this context, the phosphorescent compounds behave as host materials. As known to those skilled in the art, the host materials have high singlet and triplet energies compared to the emitters, so that the energy from the host materials can also be transferred to the emitters with maximum efficiency. The systems disclosed in the prior art have exactly such an energy relationship.

[0005] The present invention comprises a sensitizer and a fluorescent emitter, the sensitizer being a phosphorescent compound, and at least one of the following two conditions (I) or (II) must be satisfied, and it is preferred if condition (I) is satisfied:

[0006]

number

[0007] where the parameters used are as follows: X and Y are each −0.5 eV; S1 K (FE) is the energy of the first excited singlet state of the fluorescent emitter as determined from the short wavelength edge of the fluorescent emitter's normalized photoluminescence spectrum; S1 K (S) is the energy of the first excited state of the sensitizer as determined from the short wavelength edge of the normalized photoluminescence spectrum of the sensitizer; S1 max (FE) is the energy of the first excited singlet state of the fluorescent emitter as determined from the position of the first maximum at short wavelength in the photoluminescence spectrum of the fluorescent emitter; S1 max(S) is the energy of the first excited state of the sensitizer as determined from the position of the first maximum at short wavelength in the photoluminescence spectrum of the sensitizer); The photoluminescence spectra of the sensitizer and the fluorescent emitter are determined at room temperature from solutions at a concentration of 1 mg in 100 ml of toluene. Related to fluorescent electronic devices.

[0008] Further details on the determination of the prescribed parameters can be found in the Examples section of the present invention.

[0009] The experimental determination of the energy values ​​is disclosed in the Examples. The energy should be determined by this method.

[0010] The wavelength in the present invention always has the unit of nm. Therefore, expressions such as "short wavelength side of normalized photoluminescence spectrum" mean moving from short wavelength in nm (for example, from 300 nm) to longer wavelength in nm (for example, 700 nm). Therefore, shorter wavelength also always means higher energy. For the conditions specified in this specification, wavelength is converted from nm to eV.

[0011] Such devices of the present invention have been found to have particularly good performance data, especially very good efficiency, lifetime and also low voltage.

[0012] In a preferred embodiment of the invention, the fluorescent emitter is a sterically hindered fluorescent emitter.

[0013] The stereoscopic shielding is determined by the shielding factor (SF) parameter, which in the present invention is also called the shielding parameter, and is ascertained by the following method.

[0014] In the case of fluorescent emitters (also called fluorescent compounds), quantum chemical calculations are carried out, for example with the aid of the software package Gaussian09 Rev.E.01. First, the geometry of the singlet ground state is optimized using B3PW91 / 6-31G(d). For this optimized structure, a triplet single-point calculation is carried out using B3PW91 / 6-31G(d) (multiplicity 3; UDFT), from which the triplet electron density is obtained. The singlet ground state electron density is likewise obtained from a single-point calculation for the optimized structure using B3PW91 / 631-G(d). The absolute value of the difference between the triplet electron density and the singlet electron density (singlet electron density = singlet ground state electron density) is a position-dependent parameter and is called the triplet density. The triplet density is used to determine the triplet region, which is determined when the triplet density is 2*10 -4 The area where the isosurface value is 2*10 -4 For all calculations, the standard convergence criteria of Gaussian09 are used.

[0015] The "solvent-excluded surface" (also called Connolly surface) of the fluorescent compound is also calculated. This is the surface of the solvent-excluded volume (Michael L. Connolly, "Computation of Molecular Volume", J. Am. Chem. Soc., 1985, Vol. 107, p. 1118-1124). If the van der Waals volume of the fluorescent compound is considered to be a hard, i.e. impenetrable, volume, the solvent-excluded volume in the context of the present invention is the portion of space that cannot be occupied by a hard sphere of radius 0.4 nm. The solvent-excluded surface can be calculated, for example, by the algorithm described in Xu D, Zhang Y (2009), "Generating Triangulated Macromolecular Surfaces by Euclidean Distance Transform", PLoS ONE 4(12):e8140 (doi: 10.1371 / journal.pone.0008140). The algorithm is implemented, for example, in the freeware software package EDTSurf. The van der Waals radii rVDW used in the calculations are summarized in the table below:

[0016] [Table 1]

[0017] In the next step, the signed distance d between the triplet surface and the solvent-exclusion surface is calculated on the solvent-exclusion surface. The sign convention is as follows: if the solvent-exclusion surface is outside the triplet surface (seen from the center of the fluorescent compound), the sign is positive, otherwise it is negative.

[0018] Then, a surface integral I of the scalar function ed / 0.2 nm is formed over the entire solvent-excluded surface. In addition, the total area A of the solvent-excluded surface is determined. The shielding parameter SF is defined as SF=1-I / A.

[0019] Those skilled in the art can easily carry out this method with the aid of commercially available software in a routine process for determining parameters of molecular relatedness.

[0020] Here, the coefficient SF is preferably greater than or equal to 0.45, preferably greater than or equal to 0.5, very preferably greater than or equal to 0.6 and especially preferably greater than or equal to 0.65.

[0021] The shielding factor has been found to have a significant effect on the efficiency of electronic devices.

[0022] In the context of the present invention it is further preferred that X and / or Y are −0.4 eV, preferably −0.3 eV, very preferably −0.2 eV, even more preferably −0.1 eV, especially preferably 0.0 eV and most preferably 0.1 eV.

[0023] It is further preferred if X is greater than or equal to -0.2 eV, very preferably greater than or equal to -0.15 eV, more preferably greater than or equal to -0.1 eV, even more preferably greater than or equal to -0.05 eV, and most preferably greater than or equal to 0.00 eV.

[0024] It is further preferred if Y is 0.00 eV or more, even more preferably greater than 0.00 eV, even more preferably 0.01 eV or more, especially preferably 0.02 eV or more, exceptionally preferably 0.03 eV or more, very exceptionally preferably 0.05 eV or more, even more preferably 0.07 or more, and most preferably 0.10 eV or more.

[0025] In a preferred embodiment, X is -0.2 eV or more and Y is 0.00 eV or more, even more preferably greater than 0.00 eV, even more preferably 0.01 eV or more, especially preferably 0.02 eV or more, exceptionally preferably 0.03 eV or more, very exceptionally preferably 0.05 eV or more, even more preferably 0.07 or more, and most preferably 0.10 eV or more.

[0026] In a preferred embodiment, X is -0.1 eV or more and Y is 0.00 eV or more, even more preferably greater than 0.00 eV, even more preferably 0.01 eV or more, especially preferably 0.02 eV or more, exceptionally preferably 0.03 eV or more, very exceptionally preferably 0.05 eV or more, even more preferably 0.07 or more, and most preferably 0.10 eV or more.

[0027] In a preferred embodiment, X is -0.05 eV or more and Y is 0.00 eV or more, even more preferably greater than 0.00 eV, even more preferably 0.01 eV or more, especially preferably 0.02 eV or more, exceptionally preferably 0.03 eV or more, very exceptionally preferably 0.05 eV or more, even more preferably 0.07 or more, and most preferably 0.10 eV or more.

[0028] X is 0.0 eV or more, Y is 0.00 eV or more, and Y is even more preferably greater than 0.00 eV, even more preferably 0.01 eV or more, especially preferably 0.02 eV or more, exceptionally preferably 0.03 eV or more, very exceptionally preferably 0.05 eV or more, even more preferably 0.07 eV or more, and most preferably 0.10 eV or more.

[0029] It is further preferred if condition (I) is fulfilled. In addition, it is preferred if condition (II) is fulfilled. Finally, it is preferred if both conditions (I) and (II) are fulfilled.

[0030] It is preferred if the sensitizer transfers the energy it absorbs in the electronic device directly to the fluorescent emitter, which emits the excitation energy absorbed by the sensitizer by fluorescent emission.

[0031] Energy may be transferred from the sensitizer to the fluorescent emitter via a variety of mechanisms. An important pathway for the transfer of energy is believed to be Förster Resonance Energy Transfer (FRET or FET).

[0032] In a preferred embodiment of the invention, the absorption spectrum of the fluorescent emitter overlaps with the photoluminescence (emission) spectrum of the sensitizer.

[0033] The absorption spectrum of the fluorescent emitter overlaps with the photoluminescence spectrum of the sensitizer, and the triplet metal-ligand charge transfer ( 3 The size of the gap between the MLCT band and the absorption maximum of the fluorescent emitter satisfies the following condition (III):

[0034]

number

[0035] where V is 0.5 eV, V is preferably 0.4 eV, V is very preferably 0.3 eV, V is especially preferably 0.2 eV, V is even more preferably 0.15 eV, and V is especially preferably 0.1 V. It is even more preferable if

[0036] Triplet metal-ligand charge transfer in the photoluminescence spectrum of the sensitizer ( 3 MLCT) band is the parameter

[0037]

number

[0038] where the short wavelength edge in the photoluminescence spectrum of the sensitizer is found.

[0039]

number

[0040] The value of S1 already mentioned K Same as the value of (S).

[0041]

number

[0042] is the peak absorption wavelength of the first maximum at long wavelengths of the fluorescent emitter. Each value is calculated in electron volts.

[0043] Condition (IV):

[0044]

number

[0045] where W is 0.5 eV, W is preferably 0.4 eV, W is very preferably 0.3 eV, W is especially preferably 0.2 eV, W is even more preferably 0.15 eV, and W is especially preferably 0.1 V. It is particularly preferred that:

[0046] The Förster resonance energy transfer between the sensitizer and the fluorophore is represented by the following equation:

[0047]

number

[0048] (where κ is the dipole orientation factor and φ s is the quantum yield of the sensitizer, n is the refractive index of the medium, and N A is the Avogadro constant and J(λ) is the spectral overlap integral) The Förster radius R is given by 6 FRET , the spectral overlap integral can be written using the following equation:

[0049]

number

[0050] (where λ is the wavelength and F S (λ) is the normalized radiant intensity of the photoluminescence spectrum of the sensitizer, and ε FE is the molar coefficient of absorption of the fluorescent emitter) It is defined by F S Photoluminescence spectrum for determination of (λ) and ε FE Both absorption spectra for the determination of are measured from toluene solutions of the respective compounds. The Förster radii are calculated using the following settings: n = 1.7 and κ 2 =2 / 3.

[0051] A small Förster radius is preferred. It is preferred if the Förster radius is less than 3 nm, very preferably 2.5 nm or less, even more preferably 2.3 nm or less, especially preferably 2.1 nm or less. It has been found that a small Förster radius clearly improves the lifetime of electronic devices.

[0052] In another aspect of the invention, a larger Förster radius is preferred, which leads to improved efficiency of electronic devices. It is preferred if the Förster radius is 2.5 nm or more, very preferably 2.7 nm or more, even more preferably 2.8 nm or more, and especially preferably 3.0 nm or more.

[0053] The sensitizer can essentially be any phosphorescent compound, the only condition being that it has a sufficiently fast intersystem crossing (ISC) rate. A person skilled in the art can easily select a suitable compound for this purpose from the large number of suitable compounds known to him.

[0054] Phosphorescent compounds in the context of the present invention are compounds that are capable of emitting light, preferably at room temperature, under optical or electrochemical excitation in an environment such as that present in an organic electroluminescent device, where the emission results from a spin-forbidden transition, e.g., from an excited triplet state or a mixed singlet / triplet state.

[0055] Suitable phosphorescent compounds (hereinafter also referred to as triplet emitters for short) are in particular compounds which, when appropriately excited, emit light, preferably in the visible range, and which further contain at least one atom with an atomic number greater than 20, preferably greater than 38 and less than 84, more preferably greater than 56 and less than 80, in particular a metal with this atomic number.

[0056] Preferably, the sensitizer is a phosphorescent compound from the group of organometallic complexes, especially from the group of transition metal complexes.

[0057] The phosphorescent compounds preferably used are organometallic complexes containing copper, molybdenum, tungsten, rhenium, ruthenium, osmium, rhodium, iridium, palladium, platinum, silver, gold or europium, especially the compounds containing copper, iridium or platinum, very preferably iridium and platinum.In the context of the present invention, all luminescent compounds containing the above metals are considered as phosphorescent compounds.

[0058] Particularly preferred are the phosphorescent organometallic complexes described in patent applications WO2015 / 091716, in particular WO00 / 70655, WO2001 / 41512, WO2002 / 02714, WO2002 / 15645, EP1191612, WO2005 / 033244, WO2005 / 019373, US2005 / 0258742, WO2006 / 056418, WO2007 / 115970, WO2007 / 115981, WO2008 / 000727, WO2009 / 050281, WO2009 / 050290, WO2011 / 0 51404, WO2011 / 073149, WO2012 / 121936, US2012 / 0305894, WO2012 / 170571, WO2012 / 170461, WO2012 / 170463, WO2006 / 1 21811, WO2007 / 095118, WO2008 / 156879, WO2008 / 156879, WO2010 / 068876, WO2011 / 106344, WO2012 / 172482, EP3126371 , WO2015 / 014835, WO2015 / 014944, WO2016 / 020516, US2016 / 0072081, WO2010 / 086089, WO2011 / 044988, WO2014 / 008982 , WO2014 / 023377, WO2014 / 094961, WO2010 / 069442, WO2012 / 163471, WO2013 / 020631, US2015 / 0243912, WO2008 / 000726 , WO2010 / 015307, WO2010 / 054731, WO2010 / 054728, WO2010 / 099852, WO2011 / 032626, WO2011 / 157339, WO2012 / 007086, WO2015 / 036074, WO2015 / 104045, WO2015 / 117718, WO2016 / 015815, which are preferably iridium and platinum complexes.These also include organometallic complexes with multipodal ligands, as described inter alia in WO2004081017, WO2005042550, US20050170206, WO2009 / 146770, WO2010 / 102709, WO2011 / 066898, WO2016124304, WO2017032439, WO2018019688, EP3184534, WO2018 / 011186, WO2016 / 193243 and WO2015 / 091716A1.

[0059] These additionally include dinuclear organometallic complexes, such as those described in WO2011 / 045337, US2015 / 0171350, WO2016 / 079169, WO2018 / 019687, WO2018 / 041769, WO2018 / 054798, WO2018 / 069196, WO2018 / 069197, WO2018 / 069273.

[0060] These additionally include copper complexes such as those described in WO2010 / 031485, US2013 / 150581, WO2013 / 017675, WO2013 / 007707, WO2013 / 001086, WO2012 / 156378, WO2013 / 072508, EP2543672.

[0061] Examples of suitable phosphorescent palladium complexes are described in WO2014 / 109814.

[0062] In general, all phosphorescent complexes used in phosphorescent OLEDs according to the prior art and known to a person skilled in the art in the field of organic electroluminescence are suitable, and a person skilled in the art can use further phosphorescent complexes without resorting to inventive techniques.

[0063] In a preferred embodiment of the invention, when the light-emitting layer is prepared by vapor deposition, the phosphorescent compound is at a concentration in the light-emitting layer of 5% to 99.9% by volume, preferably 5% to 60% by volume, more preferably 10% to 50% by volume, and most preferably 20% to 40% by volume, where the reported percentages by volume (vol %) are based on the total volume of the light-emitting layer.

[0064] In a further preferred embodiment of the invention, when the light-emitting layer is prepared by vapor deposition, the phosphorescent compound is at a concentration in the light-emitting layer of 5% to 99.9% by volume, preferably 5% to 60% by volume, more preferably 5% to 45% by volume, and most preferably 5% to 30% by volume, where the reported percentages by volume (vol %) are based on the total volume of the light-emitting layer. do.

[0065] In yet a further preferred embodiment of the invention, when the light-emitting layer is prepared by vapor deposition, the phosphorescent compound is at a concentration in the light-emitting layer of from 1% to 50% by volume, preferably from 2% to 40% by volume, more preferably from 3% to 30% by volume, and most preferably from 4% to 25% by volume, where the reported percentages by volume (vol %) are based on the total volume of the light-emitting layer.

[0066] In a preferred embodiment of the invention, when the light-emitting layer is prepared from solution, the phosphorescent compound is at a concentration in the light-emitting layer of 5% to 99.9% by weight, preferably 5% to 60% by weight, more preferably 10% to 50% by weight, and most preferably 20% to 40% by weight, where reported percentages by mass (wt %) are based on the total weight of the light-emitting layer.

[0067] In a further preferred embodiment of the invention, when the light-emitting layer is prepared from solution, the phosphorescent compound is at a concentration in the light-emitting layer of 5% to 99.9% by weight, preferably 5% to 60% by weight, more preferably 5% to 45% by weight, and most preferably 5% to 30% by weight, where the reported percentages by weight (wt %) are based on the total weight of the light-emitting layer.

[0068] In yet a further preferred embodiment of the invention, when the light-emitting layer is prepared from solution, the phosphorescent compound is at a concentration in the light-emitting layer of from 1% to 50% by weight, preferably from 2% to 40% by weight, more preferably from 3% to 30% by weight, and most preferably from 4% to 25% by weight, where the reported percentages by weight (wt %) are based on the total weight of the light-emitting layer.

[0069] Clear examples of phosphorescent sensitizers are Ir(ppy)3 and its derivatives, the structures of which are detailed in the overview that follows.

[0070] [ka]

[0071] [ka]

[0072] [ka]

[0073] [ka]

[0074] [ka]

[0075] [ka]

[0076] [ka]

[0077] Further specific examples of phosphorescent sensitizers are the iridium and platinum complexes containing carbene ligands and the structures detailed in the overview that follows, with homoleptic and heteroleptic complexes and meridional and facial isomers being preferred:

[0078] [ka]

[0079] Further specific examples of phosphorescent sensitizers are the copper complexes and structures detailed in the overview below:

[0080] [ka]

[0081] The fluorescent emitter of the present invention may in principle be any fluorescent compound. A person skilled in the art can easily and without difficulty select a suitable emitter from the numerous fluorescent emitters.

[0082] The fluorescent emitters are preferably purely organic compounds not containing any metals or metal ions, or are fluorescent metal complexes. If the fluorescent emitters are fluorescent metal complexes, these are more preferably aluminium or copper complexes.

[0083] In one embodiment, the fluorescent emitters are fluorescent copper or aluminum complexes, more preferably sterically hindered.

[0084] Highly preferably, the fluorescent emitters are purely organic compounds lacking metals or metal ions, and even more preferably are sterically hindered.

[0085] A more detailed description of fluorescent emitters, also called fluorescent compounds, follows below.

[0086] The fluorescent emitter is preferably an organic compound.An organic compound in the context of the present invention is a carbonaceous compound that does not contain any metal.More specifically, the organic compound is formed from the elements C, H, D, B, Si, N, P, O, S, F, Cl, Br and I.In a further embodiment of the present invention, the fluorescent emitter can also be a fluorescent metal complex, for example an aluminum or copper complex.

[0087] A fluorescent compound in the context of the present invention is a compound that can emit light at room temperature under optical excitation in an environment such as that present in an organic electroluminescent device, and the emission arises from an excited singlet state. The compound preferably has a luminescence quantum efficiency of at least 60%, more preferably at least 80%, even more preferably at least 90%, and especially preferably at least 95%. The luminescence quantum efficiency is determined in a toluene solution. The method for determining the luminescence quantum yield in the context of the present invention is described in detail in general terms in WO2015 / 135624A1 "General description of the determination of the relevant parameters Part 4".

[0088] In a preferred embodiment, the peak emission wavelength of the fluorescent compound is between 430 and 650 nm. Methods for determining the peak emission wavelength in the context of the present invention are described in the examples of the present invention.

[0089] Due to differences in fabrication methods for organic electroluminescent devices, dopant concentrations of fluorescent compounds are reported in volume % when the emissive layer is fabricated by vapor deposition and in weight % when the emissive layer is fabricated from solution.

[0090] In a preferred embodiment of the invention, when the light-emitting layer is produced by vapor deposition, the fluorescent compound is present in the light-emitting layer at a dopant concentration of 0.1% to 25% by volume, preferably 1% to 20% by volume, more preferably 3% to 10% by volume.

[0091] In a preferred embodiment of the invention, when the light-emitting layer is prepared from solution, the fluorescent compound is present in the light-emitting layer at a dopant concentration of 0.1% to 25% by weight, preferably 1% to 20% by weight, more preferably 3% to 10% by weight.

[0092] Here, especially when the dopant concentration of the fluorescent compound is low, the OLED can exhibit a mixed emission composed of the fluorescent compound and the residual emission of the phosphorescent compound, which can also be utilized to generate mixed colors in a controlled manner.

[0093] The basic structure used in the fluorescent compound may be any compound as used in fluorescent OLEDs according to the prior art.

[0094] The fluorescent emitters are preferably selected from the following group of fluorescent compounds: styrylamines, indenofluorenes, polycyclic aromatic compounds, anthracene, tetracene, xanthene, perylene, phenylene, fluorene, arylpyrenes, arylenevinylenes, rubrene, coumarins, rhodamines, quinacridones, dicyanomethylenepyrans, thiopyrans, polymethines, pyrylium and thiapyrylium salts, periflanthenes, indenoperylenes, bis(azinyl)imine boron, bis(azinyl)methines, carbostyryl, monostyrylamines, distyrylamine, tristyrylamines, tetrastyrylamines, styrylphosphines, styryl ethers, arylamines, indenofluorene amines. and indenofluorenediamines, benzoindenofluoreneamines, benzoindenofluoreneamines, dibenzoindenofluoreneamines, dibenzoindenofluoreneamines, substituted or unsubstituted tristilbene amines, distyrylbenzenes and distyrylbiphenyls, triarylamines, triazolo compounds, naphthalene, phenanthrene, pyrene, triazine, chrysene, decacyclene, coronene, tetraphenylcyclopentadiene, pentaphenylcyclopentadiene, spirofluorene, pyran, oxazone, benzoxazole, benzothiazole, benzimidazole, pyrazine, cinnamate esters, diketopyrrolopyrrole, and acridone.

[0095] Further preferred fluorescent emitters are disclosed, for example, in C. H. Chen et al.: "Recent developments in organic electroluminescent materials" Macromol. Symp. 125, (1997), 1-48 and "Recent progress of molecular organic electroluminescent materials and devices" Mat. Sci. and Eng. R, 39 (2002), 143-222.

[0096] The steric shielding of these compounds is achieved by electronically inactive, sterically bulky substituents that surround the electronically active core of the fluorescent compound, thus substantially shielding it from contact with adjacent molecules in the layer.

[0097] The degree of stereoscopic shielding can be determined by the shielding parameter SF.

[0098] As mentioned above, the fluorescent core used in the fluorescent compound can be any basic structure that is commonly used as a fluorescent emitter in organic electroluminescent devices.Preferred fluorescent compounds are rigid π-systems that are substituted by large aliphatic or alicyclic radicals.In addition, aromatic substituents that may be substituted by aliphatic or alicyclic radicals are also options, provided that they are arranged so that they are not active groups in the context of the present invention in a steric sense, i.e., their proportion in the relevant molecular orbital is below the limit described below.In contrast, for example, arylamino substituents or heteroaryl groups have too large a contribution to HOMO (highest occupied molecular orbital) or LUMO (lowest unoccupied molecular orbital), and therefore are not suitable as shielding groups.

[0099] Examples of suitable aromatic base skeletons of fluorescent compounds are the groups of formulae (1) to (50) shown below:

[0100] [ka]

[0101] [ka]

[0102] [ka]

[0103] [ka]

[0104] Examples of suitable heteroaromatic base skeletons of the fluorescent compounds are the groups of formulae (1) to (50) above, in which 1, 2, 3 or 4 carbon atoms in the fused aromatic nucleus are replaced by nitrogen. Preferably, 1, 2 or 3 carbon atoms, more preferably 1 or 2 carbon atoms, most preferably exactly 1 carbon atom is replaced by nitrogen, oxygen or boron.

[0105] In addition, examples of suitable heteroaromatic base skeletons of fluorescent compounds are the groups of formulae (51) to (73) shown below:

[0106] [ka]

[0107] [ka]

[0108] These structures are substituted with sterically bulky substituents as described above, and may also be substituted with further substituents that cannot be considered sterically bulky, provided that these substituents are further substituted with substituents that are not electronically active or are sterically hindered.

[0109] Below follows a description of suitable sterically bulky substituents that can be used to replace the fluorescent cores, such as the aromatic and heteroaromatic compounds listed above, and thus arrive at sterically shielded fluorescent compounds.

[0110] Suitable sterically bulky substituents are, for example, alkyl groups, especially having 3 to 20 carbon atoms, preferably having 4 to 10 carbon atoms, in which hydrogen atoms may be replaced by F, alkoxy groups, especially having 3 to 20 carbon atoms, preferably having 4 to 10 carbon atoms, aralkyl groups, especially having 7 to 30 carbon atoms, and aromatic ring systems, especially having 6 to 30 carbon atoms, where the aralkyl groups and the aryl groups in the aromatic ring systems may also be replaced by one or more alkyl groups having 1 to 10 carbon atoms. Here, it is also possible for several adjacent substituents to form a ring system together.

[0111] When the substituent is an aralkyl group or an aromatic ring system, it is preferred if they do not have any fused aryl groups having more than 10 carbon atoms, in which aryl groups are directly fused to each other through a common edge. More preferably, they do not have any fused aryl groups in which aryl groups are directly fused to each other through a common edge. Thus, it is preferred if the aromatic ring system does not have any anthracene or pyrene groups, and it is particularly preferred if the aromatic ring system does not have any naphthalene groups. In contrast, the aromatic ring system may have, for example, biphenyl or terphenyl groups, because they do not have any fused aryl groups. In addition, the aromatic ring system may also have, for example, fluorene or spirobifluorene groups, because in these groups, aryl groups are not directly fused to each other through a common edge.

[0112] When the sterically bulky substituent is an alkyl group, the alkyl group preferably has 4 to 10 carbon atoms. A secondary, tertiary or cyclic alkyl group in which the secondary or tertiary carbon atom is either directly bonded to the fluorescent basic skeleton or bonded to the fluorescent basic skeleton via a CH2 group is preferred. More preferably, the alkyl group is one of the following formulae (R-1) to (R-33):

[0113] [ka]

[0114] (wherein the dotted bonds indicate the attachment of these groups to the fluorescent base skeleton). The structure is selected from the following:

[0115] When the sterically bulky substituent is an alkoxy group, the alkoxy group preferably has 3 to 10 carbon atoms and is preferably branched or cyclic. Preferably, the alkoxy group is represented by the following formulae (R-34) to (R-47):

[0116] [ka]

[0117] (wherein the dotted bonds indicate the attachment of these groups to the fluorescent base skeleton). The structure is selected from the following:

[0118] When the sterically bulky substituent is an aralkyl group, this aralkyl group is preferably represented by the following formulae (R-48) to (R-61):

[0119] [ka]

[0120] (In the formula, the bonds shown by dotted lines indicate the attachment of these groups to the fluorescent base skeleton, and the phenyl groups each have one or more R amay be substituted by radicals, where: R a are the same or different in each occurrence and are H, D, F, a linear alkyl group having 1 to 40 carbon atoms, or a branched or cyclic alkyl group having 3 to 40 carbon atoms (each of which may be represented by one or more R b radicals), aromatic ring systems having 5 to 60 aromatic ring atoms (each of which may be substituted with one or more R b or having 5 to 60 aromatic ring atoms and one or more R b aryl groups, optionally substituted by an aryl radical, wherein two or more adjacent R a One or more R substituents b It is optionally possible for the radicals to form an optionally substituted ring system; R b is selected from the group consisting of H, D, F, an aliphatic hydrocarbyl radical having 1 to 20 carbon atoms, and an aromatic ring system having 5 to 30 aromatic ring atoms, wherein two or more adjacent R b The substituents may together form a ring system. The structure is selected from the following:

[0121] Particularly good performance data, especially very good efficiency, of electronic devices are achieved when the fluorescent compounds are sterically shielded by aromatic ring systems. When the sterically bulky substituent is an aromatic ring system, this aromatic ring system has 6 to 60, preferably 6 to 30, more preferably 6 to 24 aromatic ring atoms. In addition, this aromatic ring system preferably contains only phenyl groups. In this case, the aromatic ring system is preferably represented by the following formulae (R-62) to (R-76):

[0122] [ka]

[0123] (In the formula, the bonds shown by dotted lines indicate the attachment of these groups to the fluorescent base skeleton, and the phenyl groups each have one or more R a may be substituted by radicals, R a is as defined above) The structure is selected from the following:

[0124] Further examples of groups suitable for steric shielding of fluorescent compounds and the substituent R a and R b A preferred embodiment of this is disclosed in WO2015 / 135624.

[0125] In a very particularly preferred embodiment of the present invention, the fluorescent emitter is a purely organic compound, devoid of metals or metal ions, selected from the group of polycyclic fused aromatics having 6 to 60 aromatic ring atoms.

[0126] Among the polycyclic fused aromatic compounds, pyrene, perylene, rubrene, anthracene, tetracene, phenanthrene, fluorene and indenofluorene are particularly preferred here, where the aromatic systems may be substituted, preferably by aromatic ring systems, as already described in detail elsewhere. Perylene and rubrene are most preferred in the context of the present invention.

[0127] Some preferred substituted perylenes that are particularly suitable for use as masked fluorescent emitters are shown below by way of example:

[0128] [ka]

[0129] [ka]

[0130] [ka]

[0131] [ka]

[0132] [ka]

[0133] [ka]

[0134] Details of perylene as a fluorescent emitter can also be found in patent application EP18194083.4.

[0135] The teachings of the present invention cover the entire color palette of emission for both the fluorescent emitters (in the photoluminescence spectrum) and the emission of the electronic devices of the present invention (in the electroluminescence spectrum).

[0136] It is preferred if the fluorescent emitter has a blue emission, where blue emission of the fluorescent emitter is preferably understood to mean an emission whose overall emission maximum in the photoluminescence spectrum of the fluorescent emitter is in the range from 380 to 500 nm.

[0137] It is also preferred if the electronic device of the invention has blue emission, where blue emission of the electronic device is preferably understood to mean an emission having a maximum of the overall emission of the electroluminescence spectrum of the electronic device of the invention in the range from 380 to 500 nm.

[0138] It is further preferred if the fluorescent emitter has a green emission, whereby green emission of the fluorescent emitter is preferably understood to mean an emission whose overall emission maximum in the photoluminescence spectrum of the fluorescent emitter is in the range from 501 to 570 nm.

[0139] It is also preferred if the electronic device of the invention has a green emission, where green emission of the electronic device is preferably understood to mean an emission having a maximum of the total emission in the electroluminescence spectrum of the electronic device of the invention in the range from 501 to 570 nm.

[0140] In addition, it is preferred if the fluorescent emitter has a yellow emission, where yellow emission of the fluorescent emitter is preferably understood to mean an emission having a total emission maximum in the photoluminescence spectrum of the fluorescent emitter in the range of 571 to 590 nm.

[0141] It is preferred if the electronic device of the invention has a yellow emission, where yellow emission of the electronic device is preferably understood to mean an emission whose overall emission maximum in the electroluminescence spectrum of the electronic device of the invention is in the range from 571 to 590 nm.

[0142] Finally, it is also preferred if the fluorescent emitter has a red emission, whereby the red emission of the fluorescent emitter is preferably understood to mean an emission whose overall emission maximum in the photoluminescence spectrum of the fluorescent emitter is in the range from 591 to 750 nm.

[0143] It is preferred if the electronic device of the invention has a red emission, whereby red emission of the electronic device is preferably understood to mean an emission whose overall emission maximum in the electroluminescence spectrum of the electronic device of the invention is in the range from 591 to 750 nm.

[0144] The sensitizer and fluorescent emitter can be in the same layer or in different layers of the electronic device.

[0145] In one embodiment of the invention, the sensitizer and the fluorescent emitter are in the same layer, which is preferably the emissive layer of the electroluminescent device.

[0146] This layer or the composition of the present invention mentioned below comprising a sensitizer and a fluorescent emitter preferably comprises at least one further material from the group of electron transport materials, hole conducting materials, quantum materials (preferably quantum dots), bipolar hosts, host materials with large band gaps (wide band gap materials), phosphorescent compounds, fluorescent compounds, and materials with delayed fluorescence.

[0147] Wide band gap material here means a material with a large band gap between the HOMO and LUMO energy levels. Particularly preferred are materials with a band gap of 2.5 eV or more, even more preferred are 3.0 eV or more, and especially preferred are 3.5 eV or more. The HOMO and LUMO values ​​should be calculated by the quantum chemical method defined below.

[0148] The material with delayed fluorescence is preferably one with thermally induced time-delayed fluorescence (TADF). TADF materials have a small gap between the S1 and T1 energy levels, which is preferably 0.3 eV or less, very preferably 0.2 eV or less, and most preferably 0.1 eV or less. The S1 and T1 energies should be calculated by the quantum chemical method defined below. Examples of standard TADF materials can be found in the prior art (e.g. Y.Liu et al., Nature Reviews Materials, Vol.3, 18020, 2018; Z.Yang et al., Chem.Soc.ReV., 2017, 46, 915).

[0149] The energy levels of materials and the energies of the lowest triplet state T1 and the lowest excited singlet state S1 are determined by quantum chemical calculations unless otherwise stated. For calculations of metal-free organic materials, first, the structure is optimized by the "ground state / semi-empirical / default spin / AM1 / charge 0 / spin singlet" method. Then, the energy calculations are performed based on the optimized structure. This is done using the "TD-SCF / DFT / default spin / B3PW91" method with the "6-31G(d)" basis set (charge 0, spin singlet). For metal-containing compounds, the structure is optimized by the "ground state / Hartree-Fock / default spin / LanL2MB / charge 0 / spin singlet" method. The energy calculations are performed similarly to the above method for organic materials, with the difference that for metal atoms, the "LanL2DZ" basis set is used, and for ligands, the "6-31G(d)" basis set is used. From the energy calculation, the HOMO energy level HEh or the LUMO energy level LEh in Hartree units is obtained, which is used to determine the HOMO and LUMO energy levels in electron volts calibrated by cyclic voltammetry measurements as follows: HOMO(eV)=((HEh*27.212)-0.9899) / 1.1206 LUMO(eV)=((LEh*27.212)-2.0041) / 1.385 In the context of this application, these values ​​will be considered to be the HOMO and LUMO energy levels of the material.

[0150] The lowest triplet state T1 is defined as the energy of the triplet state with the lowest energy, which is evident from the quantum chemical calculations given.

[0151] The lowest excited singlet state S1 is defined as the energy of the excited singlet state having the lowest energy, which is evident from the quantum chemical calculations given.

[0152] Suitable preferred matrix materials which can be used in combination with sensitizers and fluorescent emitters in the light-emitting layer of an electronic device or in the compositions of the invention mentioned below are aromatic ketones, aromatic phosphine oxides or aromatic sulfoxides or sulfones, for example according to WO2004 / 013080, WO2004 / 093207, WO2006 / 005627 or WO2010 / 006680, triarylamines, especially monoamines, carbazole derivatives, such as CBP(N,N-biscarbazolylbiphenyl) or carbazole derivatives disclosed in WO2005 / 039246, US2005 / 0069729, JP2004 / 288381, EP1205527 or WO2008 / 086851, such as indolocarbazole derivatives according to WO2007 / 063754 or WO2008 / 056746, such as indenocarbazole derivatives according to WO2010 / 136109 and WO2011 / 000455, such as EP1617710 azacarbazole derivatives according to, for example, EP 1617711, EP 1731584, JP 2005 / 347160, bipolar matrix materials according, for example, to WO 2007 / 137725, silanes according, for example, to WO 2005 / 111172, azaboroles or boronic acid esters according, for example, to WO 2006 / 117052, triazine derivatives according, for example, to WO 2010 / 015306, WO 2007 / 063754 or WO 2008 / 056746, for example, EP 652273 or zinc complexes according to WO2009 / 062578, diazasirol or tetraazasirol derivatives, for example, according to WO2010 / 054729, diazaphosphole derivatives, for example, according to WO2010 / 054730, bridged carbazole derivatives, for example, according to US2009 / 0136779, WO2010 / 050778, WO2011 / 042107, WO2011 / 088877 or WO2012 / 143080, trifluoromethane derivatives, for example, according to WO2012 / 048781, In particular, preferred phosphorescent emitters include phenylene derivatives, for example lactams according to WO2011 / 116865, WO2011 / 137951 or WO2013 / 064206, 4-spirocarbazole derivatives, for example according to WO2014 / 094963 or WO2015 / 192939, or dibenzofuran derivatives, for example according to WO2015 / 169412, WO2016 / 015810, WO2016 / 023608 or the unpublished applications EP16158460.2 and EP16159829.7. It is likewise possible for further phosphorescent emitters, which emit at shorter wavelengths than the actual emitter, to be present in the emitting layer or composition.

[0153] The further material is preferably selected from the group of electron transport materials, especially those selected from the group of pyridines, pyrimidines, pyrazines, pyridazines, triazines, quinazolines, quinoxalines, quinolines, isoquinolines, imidazoles, lactams, dibenzofurans, dibenzothiophenes and / or benzimidazoles, with pyrimidines and triazines being very particularly preferred.

[0154] It is furthermore preferred if the further material is selected from the group of hole-transporting materials, where carbazoles, biscarbazoles, arylamines, triarylamines, indenocarbazoles and indolocarbazoles are very particularly preferred.

[0155] It is further preferred if the layer comprising the sensitizer and the fluorescent emitter and the further material comprises at least one fourth material, whereby the fourth material may again be selected from the group of preferred further materials already mentioned above.

[0156] In a further embodiment of the invention the layer comprising sensitizer and fluorescent emitter consists exclusively of sensitizer and fluorescent emitter, the layer being preferably an emissive layer.

[0157] In a further embodiment of the invention, the sensitizer and the fluorescent emitter are in different layers, where the two layers are immediately adjacent to each other.

[0158] It is also possible for several layers, each containing a sensitizer and a fluorescent emitter, to adjoin one another in an alternating manner. The invention therefore relates to a layer sequence [SL / FEL] n Also provided is an electronic device containing a region having -SL, where n is an integer from 1 to 5, SL is a layer containing a sensitizer, and FEL is a layer containing a fluorescent emitter, and the sensitizers in different SL layers may be different from each other and the fluorescent emitters in different FEL layers may be different from each other.

[0159] The electronic device of the present invention is preferably an organic electronic device, very preferably an organic electronic device from the group of organic electroluminescent devices, organic integrated circuits, organic field effect transistors, organic thin film transistors, organic light emitting transistors, organic solar cells, organic optical detectors, organic photoreceptors, organic field quenching devices, light emitting electrochemical cells or organic laser diodes.

[0160] Most preferably, the electronic device is an organic electroluminescent device. Even more preferred, if the electronic device is an organic electroluminescent device from the group of OLEDs and OLECs, OLEDs being most preferred.

[0161] A preferred embodiment of the present invention is an organic electroluminescent device. An organic electroluminescent device comprises a cathode, an anode and at least one light-emitting layer. In addition to these layers, it may comprise further separate layers, for example in each case one or more hole injection layers, hole transport layers, hole blocking layers, electron transport layers, electron injection layers, exciton blocking layers, electron blocking layers, charge generation layers, and / or organic or inorganic p / n junctions. At the same time, it is possible to p-dope one or more hole transport layers, for example with metal oxides, for example MoO3 or WO3, or with (per)fluorinated electron-deficient aromatic systems, and / or n-dope one or more electron transport layers. It is also possible to introduce intermediate layers between two light-emitting layers, for example with exciton blocking function and / or to control the charge balance in the electroluminescent device. However, it should be pointed out that each of these layers does not necessarily have to be present.

[0162] In this case, the organic electroluminescent device can contain an emitting layer or contain several emitting layers. If several emitting layers are present, they preferably have several emission maxima at 380 nm to 750 nm, and produce a white light emission as a whole; in other words, various emitting compounds that can fluoresce or phosphoresce are used in the emitting layers. Particularly preferred are three-layer systems (for basic configurations, see, for example, WO2005 / 011013) in which three layers exhibit blue, green and orange or red emission, or systems with four or more emitting layers. Furthermore, tandem OLEDs are also preferred. The system can also be a hybrid system in which one or more layers fluoresce and one or more other layers phosphoresce.

[0163] Preferred cathodes are metals, metal alloys, multilayer structures made of various metals, such as alkaline earth metals, alkali metals, main group metals or lanthanides (e.g. Ca, Ba, Mg, Al, In, Mg, Yb, Sm, etc.) with low work functions. In addition, suitable are alloys made of alkali metals or alkaline earth metals and silver, such as alloys made of magnesium and silver. In the case of multilayer structures, in addition to the metals mentioned, it is also possible to use further metals with relatively high work functions, such as Ag, in which case metal combinations such as Mg / Ag, Ca / Ag or Ba / Ag are commonly used. It may be preferable to introduce a thin intermediate layer of a material with a high dielectric constant between the metallic cathode and the organic semiconductor. Examples of materials useful for this purpose are alkali metal or alkaline earth metal fluorides as well as the corresponding oxides or carbonates (e.g. LiF, Li2O, BaF2, MgO, NaF, CsF, Cs2CO3, etc.). Also useful for this purpose are organic alkali metal complexes, such as Liq (lithium quinolinate). The thickness of this layer is preferably 0.5 to 5 nm.

[0164] Preferred anodes are materials with a high work function. Preferably, the anode has a work function of more than 4.5 eV vs. vacuum. Firstly, metals with high redox potentials are suitable for this purpose, such as Ag, Pt or Au. Secondly, metal / metal oxide electrodes (e.g. Al / Ni / NiO x , Al / PtO x ) may be preferred. Depending on the application, at least one of the electrodes must be transparent or partially transparent to allow either irradiation (O-SC) or light emission (OLED / PLED, O-laser) of the organic material. Preferred anode materials here are conductive mixed metal oxides. Indium tin oxide (ITO) or indium zinc oxide (IZO) are particularly preferred. Furthermore, conductive doped organic materials are preferred, especially conductive doped polymers, such as PEDOT, PANI or derivatives of these polymers. It is further preferred to apply a p-doped hole transport material to the anode as a hole injection layer, in which case suitable p-dopants are metal oxides, such as MoO3 or WO3, or (per)fluorinated electron-deficient aromatic systems. Further suitable p-dopants are HAT-CN (hexacyanohexaazatriphenylene) or the compound NPD9 from Novaled. Such a layer simplifies hole injection into materials with a low HOMO, i.e. a high HOMO in terms of intensity.

[0165] In the further layers it is generally possible to use any material as is used according to the prior art for layers, and the skilled person can combine any of these materials with the materials of the invention in an electronic device without the use of inventive techniques.

[0166] The present invention further relates to a composition comprising at least one sensitizer and at least one fluorescent emitter, the sensitizer and the fluorescent emitter being compounds as defined in the present invention. Moreover, with regard to this two-component embodiment of the composition which is preferred in the context of the present invention, i.e. with regard to the sensitizer and the fluorescent emitter, the same preferences as already disclosed herein and described in relation to the electronic device are applicable.

[0167] It is therefore preferred if the fluorescer and sensitizer of the composition satisfy at least one of the above conditions (I) or (II), and preferably if condition (I) is satisfied, where, for example, with respect to X and Y, the preferences set out above are also applicable here.

[0168] It is therefore even more preferred if the fluorescent emitter of the composition is a sterically hindered compound having a shielding factor (SF) of 0.45 or more, preferably 0.5 or more, very preferably 0.6 or more and especially preferably 0.65 or more.

[0169] Therefore, another highly preferred composition in this context is one which comprises, for example, at least one sensitizer, a phosphorescent organometallic complex containing Ir or Pt, and a sterically hindered fluorescent emitter having one of the shielding coefficients detailed above.

[0170] Therefore, another highly preferred composition in this context is one which comprises at least one sensitizer, a phosphorescent organometallic complex containing Ir or Pt, and a fluorescent emitter, in which at least one of the two conditions (I) and (II) must be met.

[0171] The composition preferably comprises at least one further material preferably selected from the group of electron transport materials, electron injection materials, electron blocking materials, hole transport materials, hole injection materials, hole blocking materials, n-dopants, p-dopants, quantum materials (preferably quantum dots), host or matrix materials, wide band gap materials, phosphorescent emitters, fluorescent emitters or emitters with delayed fluorescence, the materials being the materials mentioned in connection with the electronic device.

[0172] The materials mentioned are well known to those skilled in the art, who can now select from the multitude of readily available materials known to them.

[0173] The composition of the present invention preferably contains the sensitizer in a concentration of from 5% to 99.9% by weight, very preferably from 5% to 60% by weight, especially preferably from 10% to 50% by weight, most preferably from 20% to 40% by weight, the figures being based on the total composition.

[0174] The composition of the invention preferably contains the fluorescent emitter in a concentration of 0.1% to 25% by weight, very preferably 1% to 20% by weight, especially preferably 3% to 10% by weight, the figures being based on the total composition.

[0175] The present invention also provides a formulation comprising the composition mentioned and at least one solvent.

[0176] Suitable solvents are preferably organic solvents, such as alcohols, aldehydes, ketones, ethers, esters, amides, di-C1-C2-alkylformamides, sulfur compounds, nitrogen compounds, hydrocarbons, halogenated hydrocarbons (e.g. chlorinated hydrocarbons), aromatic or heteroaromatic hydrocarbons, and halogenated aromatic or heteroaromatic hydrocarbons.

[0177] Preferred solvents may be selected from the following group: substituted and unsubstituted aromatic or linear esters, such as ethyl benzoate, butyl benzoate, octyl octanoate, diethyl sebacate; substituted and unsubstituted aromatic or linear ethers, such as 3-phenoxytoluene, 3,4-dimethylanisole, phenetole or anisole; substituted and unsubstituted arenes, such as toluene, xylene, pentylbenzene, hexylbenzene, cyclohexylbenzene, 2-methylbiphenyl, 2,2'-dimethylbiphenyl; indanes, such as hexamethylindane; substituted and unsubstituted aromatic or linear ketones; substituted and unsubstituted heterocyclic compounds, such as pyrrolidinone, cyclic or acyclic siloxanes, pyridine, pyrazine; or other fluorinated or chlorinated aromatic hydrocarbons.

[0178] Particularly preferred solvents are, for example, 1,2,3,4-tetramethylbenzene, 1,2,3,5-tetramethylbenzene, 1,2,3-trimethylbenzene, 1,2,4,5-tetramethylbenzene, 1,2,4-trichlorobenzene, 1,2,4-trimethylbenzene, 1,2-dihydronaphthalene, 1,2-dimethylnaphthalene, 1,3-benzodioxolane, 1,3-diisopropylbenzene, 1,3-dimethylnaphthalene, 1,4-benzodioxane, 1,4-diisopropylbenzene, 1,4-dimethylnaphthalene, 1,5-dimethyltetralin, 1-benzothiophene, thianaphthalene, 1-bromonaphthalene, , 1-chloromethylnaphthalene, 1-ethylnaphthalene, 1-methoxynaphthalene, 1-methylnaphthalene, 1-methylindole, 2,3-benzofuran, 2,3-dihydrobenzofuran, 2,3-dimethylanisole, 2,4-dimethylanisole, 2,5-dimethylanisole, 2,6-dimethylanisole, 2,6-dimethylnaphthalene, 2-bromo-3-bromomethylnaphthalene, 2-bromonaphthalene, 2-ethoxynaphthalene, 2-ethylnaphthalene, 2-isopropylanisole, 2-methylanisole, 2-methylindole, 3,4-dimethylanisole, 3,5-Dimethylanisole, 3-Bromoquinoline, 3-Methylanisole, 4-Methylanisole, 5-Decanolide, 5-Methoxyindan, 5-Methoxyindole, 5-Tert-Butyl-m-Xylene, 6-Methylquinoline, 8-Methylquinoline, Acetophenone, Anisole, Benzonitrile, Benzothiazole, Benzyl Acetate, Bromobenzene, Butyl Benzoate, Butylphenyl Ether, Cyclohexylbenzene, Decahydronaphthol, Dimethoxytoluene, 3-Phenoxytoluene, Diphenyl Ether, Propiophenone, Ethylbenzene, Ethyl Benzoate, Hexylbenzene, Indane, Hexamethylindane, indene, isochroman, cumene, m-cymene, mesitylene, methyl benzoate, o-, m-, p-xylene, propyl benzoate, propylbenzene, o-dichlorobenzene, pentylbenzene, phenetole, ethoxybenzene, phenyl acetate, p-cymene, propiophenone, sec-butylbenzene, t-butylbenzene, thiophene, toluene, veratrole, monochlorobenzene, o-dichlorobenzene, pyridine, pyrazine, pyrimidine, pyrrolidinone, morpholine, dimethylacetamide, dimethylsulfoxide, decalin and / or mixtures of these solvents.

[0179] The present invention also provides an electronic device, preferably an electronic device as described above, which preferably comprises the composition, especially in the light-emitting layer of an organic electroluminescent device.

[0180] The present invention further provides a method for manufacturing an electronic device, wherein at least one layer of the electronic device is manufactured from solution using a formulation of the present invention.

[0181] The invention also provides a method for manufacturing an electronic device, in which at least one layer of the electronic device is deposited from a vacuum using a composition of the invention.

[0182] Correspondingly, the devices are structured (depending on the application), the contacts are connected and finally sealed, since the lifetime of such devices is significantly shortened in the presence of water and / or air.

[0183] Additionally preferred are electronic devices, especially organic electroluminescent devices, characterized in that one or more layers are coated by a sublimation process. In this case, the material is typically deposited in a vacuum sublimation system at 10 -5 Less than mbar, preferably less than 10 -6 The initial pressure may be lower or higher, for example 10 -7 It is also possible to go below mbar.

[0184] Likewise preferred are electronic devices, especially organic electroluminescent devices, characterized in that one or more layers are coated by the OVPD (organic vapor phase deposition) method or with the aid of carrier gas sublimation. In this case, the materials are preferably -5 It is applied at pressures between mbar and 1 bar. A special case of this method is the OVJP (Organic Vapor Jet Printing) method, in which the material is applied directly by a nozzle and thus structured (eg, MS Arnold et al., Appl. Phys. Lett. 2008, 92, 053301).

[0185] In addition, electronic devices, especially organic electroluminescent devices, are preferred, characterized in that one or more layers are produced from solution, for example by spin-coating or by any printing method, such as screen printing, flexographic printing, offset printing or nozzle printing, but more preferably by LITI (Light Induced Thermal Imaging, Thermal Transfer Printing) or inkjet printing. For this purpose, soluble compounds are required, which can be obtained, for example, by suitable substitution.

[0186] Electronic devices, especially organic electroluminescent devices, can also be produced as hybrid systems by applying one or more layers from solution and one or more other layers by vapor deposition. Thus, for example, a light-emitting layer comprising the composition of the invention can be applied from solution, to which a hole-blocking layer and / or an electron-transporting layer can be applied by vapor deposition under reduced pressure.

[0187] Those skilled in the art will recognize these methods in general terms and can apply them without difficulty to the electronic devices of the present invention, in particular to the organic electroluminescent devices. [Brief description of the drawings]

[0188] [Figure 1] FIG. 1 shows the photoluminescence spectra of compounds FE-03 and PS-01. [Diagram 2] FIG. 2 shows the electroluminescence spectrum from experiment 6.

[0189] The devices of the present invention and devices comprising the compositions of the present invention are characterized by the following surprising advantages over the prior art: 1. The devices of the present invention and devices comprising the compositions of the present invention exhibit improved performance data, especially efficiency, lifetime and operating voltage, compared to prior art compounds and compositions.

[0190] 2. The devices of the present invention and devices comprising the compositions of the present invention allow the use of practical or even higher concentrations of fluorescent emitters compared to the prior art, which has the advantage of improved processability of the light-emitting layer.

[0191] 3. The compositions and formulations of the present invention allow for simple and inexpensive processing of electronic devices, including simple processing from solution, and therefore, they are suitable for commercial use and mass production.

[0192] 4. The compositions of the present invention and the formulations of the present invention have improved stability, so that the compositions and formulations are easy to store.

[0193] It should be pointed out that variations of the embodiments described in the present invention are included within the scope of the present invention. Any feature disclosed in the present invention may be replaced by an alternative feature serving the same purpose or an equivalent or similar purpose, unless expressly excluded. Therefore, any feature disclosed in the present invention should be considered as an example of a generic series, or an equivalent or similar feature, unless otherwise specified.

[0194] All features of the present invention may be combined with one another in any manner, unless certain features and / or steps are mutually exclusive. This is particularly true for preferred features of the present invention. Similarly, features of non-essential combinations may be used individually (and not in combination).

[0195] It should further be pointed out that many features, particularly those of the preferred embodiments of the invention, are inventive in themselves and should not be considered as merely part of an embodiment of the invention, and that independent protection can be sought for these features in addition to, or as an alternative to, any invention claimed herein.

[0196] The technical teachings disclosed by the present invention may be extracted and combined with other examples.

[0197] The present invention will be illustrated in more detail in the examples that follow, without any intention of limiting the invention thereby.

[0198] Using the details given, a person skilled in the art can manufacture further electronic devices of the present invention without the use of inventive techniques, and thus can practice the present invention throughout the entire scope of the claims. [example] Example 1 optical physical measurements 1.1) Peak emission wavelength λ maxFrom S1 max Judgment of To determine the peak emission wavelengths of the sensitizers and fluorescers, the particular materials are dissolved in toluene. A concentration of 1 mg / 100 ml is used here. The solution is excited in a Hitachi F-4500 fluorescence spectrometer, with wavelengths adapted in each case to the material to be analyzed. The measurements are carried out at room temperature. Peak emission wavelength λ max is the wavelength at which the resulting emission spectrum achieves its first maximum, proceeding from the shorter wavelengths (FIG. 1). The first maximum here is typically also the global maximum of the spectrum. However, if the first maximum of the emission spectrum does not correspond to the global maximum, the first maximum has a high intensity in the normalized emission spectrum, in which case the intensity of the first maximum is at least 0.5 or more.

[0199] 1.2) S1 from the light-emitting edge K Judgment of To determine the emission edge of the sensitizer and fluorophore, a tangent line is drawn to the normalized photoluminescence spectrum at the position of steepest slope before the first maximum at short wavelength. The intersection of this tangent line with the x-axis is the emission edge λ edge gives the wavelength of light (as shown in Figure 1).

[0200] The above photophysical measurements provide the peak emission wavelengths and emission edges for the sensitizers and fluorescers in Table 1. For the fluorescers, the shading factor (SF) is given as well.

[0201] [Table 2]

[0202] Example 2 Synthesis of fluorescent emitters The perylene used herein can be produced according to the principles detailed below.

[0203] Synthesis scheme:

[0204] [ka]

[0205] (In the formula, X 1 ~X 3 represents an optional substituent).

[0206] Synthesis of triflates:

[0207] [ka]

[0208] (In the formula, R 1 ~R 3 The group is X 1 ~X 3 (has the same meaning as the group).

[0209] A sintered flask filled with Ar and equipped with a precision glass stirrer is initially charged with 2,5,8,11-tetra-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)perylene (38.0 g, 50.3 mmol, 1.0 equiv.), 3-phenyl-[1,1'-biphenyl]-2-yl trifluoromethanesulfonate (95.1 g, 251.3 mmol, 5.0 equiv.), tetrakis(triphenylphosphine)palladium (5.81 g, 5.0 mmol, 0.1 equiv.) and sodium metaborate tetrahydrate (69.3 g, 502.5 mmol, 10.0 equiv.). To this is added THF (1500 ml) and water (500 ml) and the reaction mixture is stirred under reflux for 3 days. The crude product is purified by column chromatography. The desired product is isolated as a yellow solid (16 g, 13.7 mmol, 27.3%).

[0210] Synthesis of 2,5,8,11-tetrakis(2,6-dimethylphenyl)perylene [FE-02]

[0211] [ka]

[0212] A sintered 4-neck flask filled with Ar and equipped with a precision glass stirrer is initially charged with 2,5,8,11-tetra-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)perylene (40.0 g, 52.9 mmol, 1.0 equiv.), 2-bromo-1,3-dimethylbenzene (293.7 g, 212.8 ml, 1587.0 mmol, 30.0 equiv.) and cesium carbonate (137.9 g, 423.2 mmol, 8.0 equiv.). Toluene (2000 ml) is added and the reaction mixture is degassed with Ar for 20 min. Subsequently, tetrakis(triphenylphosphine)palladium (6.11 g, 5.3 mmol, 0.1 equiv.) is added and the reaction mixture is degassed for another 20 min. Subsequently, the reaction is stirred under reflux for 72 h. The reaction mixture is filtered. The mother liquor is concentrated, the resulting suspension is filtered, and methanol (1000 ml) is added to the resulting mother liquor. In the process, a solid precipitates. All the solids are combined and subjected to hot extraction with toluene over AlOx three times. Hot extraction is performed once more with a mixture of toluene and heptane (1:1) over AlOx. The resulting solid is recrystallized twice from toluene and once from 1,4-dioxane. The desired product is isolated as a yellow solid (5.0 g, 7.47 mmol, 14.1%). The solid is subsequently sublimed (4.5 g, 6.73 mmol, 12.7%).

[0213] Synthesis of 2,5,8,11-tetrakis(2,6-diphenylphenyl)perylene [FE-03]

[0214] [ka]

[0215] A sintered four-neck flask filled with Ar and equipped with a precision glass stirrer is initially charged with 2,5,8,11-tetra-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)perylene (38.0 g, 50.3 mmol, 1.0 equiv.), 1,3-diphenylphenyl triflate (95.1 g, 251.3 mmol, 5.0 equiv.) and sodium metaborate tetrahydrate (69.3 g, 502.5 mmol, 10.0 equiv.). THF (1500 ml) and water (500 ml) are added and the reaction mixture is degassed with Ar for 20 min. Subsequently, tetrakis(triphenylphosphine)palladium (5.81 g, 5.0 mmol, 0.1 equiv.) is added and the reaction mixture is degassed with Ar for another 20 min. Subsequently, the reaction is stirred under reflux for 72 h. The reaction mixture is cooled and subjected to hot extraction with toluene over AlOx. This procedure is repeated two more times, after which the solid is recrystallized from toluene (700 ml). After five more recrystallizations, the desired product can be isolated as a yellow solid (16 g, 13.7 mmol, 27.3%). The solid is then sublimed (6.8 g, 5.8 mmol, 11.6%).

[0216] Example 3 Organic Electroluminescent Devices OLED manufacturing A glass plaque coated with a 50 nm thick structured ITO (indium tin oxide) is subjected to wet cleaning (dishwasher, Merck Extran cleaning agent). The substrate is then treated with UV / ozone for 15 min. Afterwards a 20 nm PEDOT:PSS layer is spun onto the substrate (2800 rpm). The substrate is baked again for 10 min at 180 °C on a hotplate. After fabrication the OLED is encapsulated to protect it against oxygen and water vapor. The exact layer configuration of the electroluminescent OLED (organic light emitting diode) can be found in the examples. The materials required for the fabrication of the OLED are shown in Table 4.

[0217] All materials are applied by thermal evaporation in a vacuum chamber. The emissive layer here always consists of at least one matrix material (host material), a (phosphorescent) sensitizer (PS) and a fluorescent emitter (FE). The sensitizer and fluorescent emitter (FE) are added to the host material (H) in a certain volumetric proportion by co-evaporation. Details given in the form H-01:PS-01(5%):FE-01(3%) here mean that in the layer the material H-01 is present in a proportion of 92% by volume, PS-01 in a proportion of 5% and FE-01 in a proportion of 3%. Similarly, the electron transport layer may also consist of a mixture of two materials.

[0218] OLEDs are characterized in the standard way. For this purpose, the electroluminescence spectrum (EL) and the current-voltage-luminance (UIL) characteristics are measured, from which it is possible to determine the external quantum efficiency (EQE, measured in %) assuming Lambertian emission characteristics. The parameter U100 is the efficiency of 100 cd / m 2 EQE100 refers to the voltage required for a brightness of 100cd / m 2 This refers to the external quantum efficiency at the operating brightness of

[0219] The lifetime LD is defined as the time it takes for the luminance to decrease by a certain percentage L1 from the initial luminance during operation at a constant current j0 = 10 mA / cm 2 , L1=80% is 10mA / cm 2 This means that in the course of operation at 1000 Hz, the luminance will drop to 80% of its initial value after a period of time LD.

[0220] The phosphorescent sensitizers used are the compounds PS-01, PS-02, PS-03, PS-04 and PS-05. The fluorescent emitters used are the materials FE-01, FE-02, FE-03, FE-04, FE-05, FE-06 and FE-07.

[0221] Blue-emitting OLED: The OLED consists of the following layer sequence applied to the substrate after PEDOT:PSS processing: For experiments 1–16: 20 nm HTM:pD (95%:5%), 30 nm HTM, 10 nm H-02, 25 nm H-01:PS:FE, 10 nm H-01, 20 nm ETM:LiQ (50%:50%), aluminum (100 nm).

[0222] For experiments 17–22: 20 nm HTM:pD (95%:5%), 20 nm HTM, 10 nm H-03, 30 nm H-01:PS:FE, 10 nm H-01, 20 nm ETM:LiQ (50%:50%), 3 nm LiQ, aluminum (100 nm).

[0223] For experiments 23-28, substrates with 50 nm of ITO are used, which have been subjected to wet cleaning (dishwasher, Merck Extran cleaning agent). The substrates are then baked for 15 min at 250 ° in a nitrogen atmosphere. The OLED consists of the following layer sequence applied to the substrate after baking: 20 nm of HTM:pD (95%:5%), 180 nm of HTM, 20 nm of H-03, 25 nm of H-01:PS-04:FE, 10 nm of H-01, 20 nm of ETM:LiQ (50%:50%), aluminum (100 nm).

[0224] Table 2 lists the results for various combinations of hosts, sensitizers and fluorescent emitters. 2 The EQE and voltage at are reported for the corresponding experiments. X here is the S1 K (FE)-S1 K (S), and Y represents S1 max (FE)-S1 max Represents (S).

[0225] [Table 3]

[0226] Fluorescent compounds with higher screening parameter SF in the emissive layer containing phosphorescent sensitizers Compared to FE-01, which has an SF value of only 0.41, the phosphor FE-02 (SF=0.55) gives a much higher efficiency (EQE100=9.32% run 4 vs. EQE100=6.77% run 2). The efficiency increase is even larger (EQE100=17.9% run 7) when using phosphor FE-03 (SF=0.72).

[0227] In a reference experiment with PS-01 and no FE, a phosphorescent device with EQE100=21.72% and U100=3.67V is obtained. Surprisingly, the efficiency of the device of the invention is only slightly lower than that of the phosphorescent device. However, the lifetime can be clearly improved with FE. In experiment 6, the device of the invention has a j0=10 mA / cm compared to the device without fluorescent emitter. 2 , At L1 = 80%, a two-fold improvement in life is obtained.

[0228] When PS-05 is used as a sensitizer, increasing the shielding factor also results in increased efficiency. Comparing examples 17 and 20 or 18 and 21 or 19 and 22, it can be seen that FE-03 with the same composition gives much better EQE100 values ​​than FE-01.

[0229] Effect of Fluorescent Material Concentration Increasing the concentration of fluorescent emitter significantly improves the lifetime of the OLED (eg, experiment 8 vs. experiment 6).

[0230] When FE-01 is used as the emitter together with another phosphorescent sensitizer (PS-02) as in experiment 9, EQE100 = 13% and U100 = 3.33V are obtained.

[0231] The results in Table 2 reveal that with increasing shielding factor there is an unexpected physically and statistically significant increase in efficiency (EQE) (Table 1). Moreover, it can be said, surprisingly, that the efficiency (EQE) is still at a very high level even when the X and Y values ​​are increased and even become positive. Furthermore, with increasing X and Y values ​​the lifetime improves. This can also be shown by using the sensitizer / illuminator combinations PS-04 and FE-01 and FE-03 (runs 23-28).

[0232] Yellow-emitting OLED The OLED consists of the following layer sequence applied to the substrate: 20 nm HTM:pD (95%:5%), 30 nm HTM, 10 nm H-02, 15 nm H-01:PS-03:FE, 10 nm H-01, 40 nm ETM:LiQ (50%:50%), Aluminum (100 nm). The various combinations in the emissive layers are summarized in Table 3:

[0233] [Table 4]

[0234] Just as with blue-emitting OLEDs, the same effect is observed in yellow-emitting OLEDs that contain a different class of fluorescent emitter.

[0235] [Table 5-1]

[0236] [Table 5-2]

[0237] [Table 5-3]

[0238] [Table 5-4]

Claims

1. A fluorescent electronic device comprising a sensitizer and a fluorescent emitter, wherein the sensitizer is a phosphorescent compound, must satisfy at least one of the following two conditions (I) or (II): [0010] where the parameters used are as follows: X and Y are each −0.5 eV, S １ Ｋ (FE) is the energy of the first excited singlet state of the fluorescent emitter as determined from the edge of the first maximum on the short wavelength side of the normalized photoluminescence spectrum of the fluorescent emitter; S １ Ｋ (S) is the energy of the first excited state of the sensitizer as determined from the edge of the first maximum on the short wavelength side of the normalized photoluminescence spectrum of the sensitizer; S １ ｍａｘ (FE) is the energy of the first excited singlet state of the fluorescent emitter as determined from the position of the first maximum at short wavelength in the photoluminescence spectrum of the fluorescent emitter; S １ ｍａｘ (S) is the energy of the first excited state of the sensitizer as determined from the position of the first maximum at short wavelength of the photoluminescence spectrum of the sensitizer; The photoluminescence spectra of the sensitizer and the fluorescent emitter are determined at room temperature from a solution at a concentration of 1 mg in 100 ml of toluene; the fluorescent emitter is a sterically hindered compound having a shielding factor (SF) of 0.5 or more, and both the sensitizer and the fluorescent emitter are in the same layer; and The magnitude of the triplet metal-ligand charge transfer ( 3 MLCT) band in the photoluminescence spectrum of the sensitizer and the absorption maximum of the fluorescent emitter satisfy the following condition (III): [0025] (Wherein, V is 0.5 eV; [0030] is the triplet metal-ligand charge transfer ( 3 MLCT) band of the photoluminescence spectrum of the sensitizer, found from the edge in the photoluminescence spectrum of the sensitizer; [0045] is the peak absorption wavelength of the first maximum at long wavelength of the fluorescent emitter. and each of said values ​​is calculated in electron volts. A fluorescent electronic device comprising:

2. 10. The electronic device of claim 1, wherein the fluorescent emitter is a sterically hindered compound having a shielding factor (SF) of 0.6 or greater.

3. The device of claim 1 or 2, wherein X and Y are −0.4 eV.

4. A device according to any one of claims 1 to 3, characterized in that both conditions (I) and (II) are fulfilled.

5. The device according to any one of claims 1 to 4, characterized in that excitation energy is transferred from the sensitizer to the fluorescent emitter, and the fluorescent emitter emits the excitation energy absorbed by the sensitizer by emitting fluorescence.

6. The device according to any one of claims 1 to 5, characterized in that the photoluminescent emission spectrum of the sensitizer overlaps with the absorption spectrum of the fluorescent emitter.

7. The device according to any one of claims 1 to 6, characterized in that a metal-ligand charge transfer (MLCT) band of the photoluminescence spectrum of the sensitizer overlaps with the absorption spectrum of the fluorescent emitter.

8. The following condition (IV): [0050] (Wherein, W is 0.5 eV; [006] is the triplet metal-ligand charge transfer ( ３ MLCT) band, found at the edge in the photoluminescence spectrum of the sensitizer; [0070] is the peak absorption wavelength of the first maximum at long wavelength of the fluorescent emitter. is satisfied, and each of said values ​​is calculated in electron volts. A device according to any one of claims 1 to 7, characterized in that it is

9. The device according to any one of the preceding claims, characterized in that the sensitizer is a phosphorescent compound from the group of organometallic complexes.

10. 10. The device according to claim 1, wherein the sensitizer is a phosphorescent compound from the group of organometallic complexes containing Cu, Ir, Pt, Rh, Ru, Os or Pd.

11. A device according to any one of claims 1 to 10, characterized in that the fluorescent emitter is a purely organic compound lacking metals or metal ions.

12. 12. The device according to claim 1, wherein the fluorescent emitter is a purely organic compound, devoid of metals or metal ions, selected from the group of fused aromatic compounds having 6 to 60 aromatic ring atoms.

13. 13. The device according to claim 1, wherein the fluorescent emitter is a purely organic compound, devoid of metals or metal ions, selected from the group: pyrene, perylene, rubrene, anthracene, fluorene and indenofluorene.

14. 14. A device according to any one of claims 1 to 13, characterized in that the fluorescent emitter is a purely organic compound, devoid of metals or metal ions, having aromatic groups in substituted form.

15. A device according to any one of claims 1 to 14, characterized in that the sensitizer and the fluorescent emitter are in an emissive layer.

16. 16. The device of claim 15, characterized in that the layer in which the sensitizer and the fluorescent emitter are present contains a further material selected from the group of electron transport materials, hole conducting materials, quantum materials, bipolar hosts, wide band gap materials, phosphorescent emitters, fluorescent emitters, materials with delayed fluorescence.

17. 16. The device of claim 15, characterized in that the layer in which the sensitizer and the fluorescent emitter are present does not contain any further material selected from the group of electron transport materials, hole conducting materials, quantum materials, bipolar hosts, wide band gap materials, phosphorescent emitters, fluorescent emitters, materials with delayed fluorescence.

18. A device according to any one of the preceding claims, characterized in that the fluorescent emitter is a sterically hindered compound having a shielding factor (SF) of 0.65 or more.

19. A composition comprising at least one sensitizer and at least one fluorescent emitter, wherein the fluorescent emitter is a sterically hindered compound having a shielding factor (SF) of 0.5 or more, and the sensitizer is a phosphorescent compound, at least one of the following two conditions (I) and (II) must be satisfied: [0080] The symbols used have the meanings given in claim 1, The magnitude of the triplet metal-ligand charge transfer ( 3 MLCT) band in the photoluminescence spectrum of the sensitizer and the absorption maximum of the fluorescent emitter satisfy the following condition (III): [0097] (Wherein, V is 0.5 eV; [0089] is the triplet metal-ligand charge transfer ( 3 MLCT) band of the photoluminescence spectrum of the sensitizer, found from the edge in the photoluminescence spectrum of the sensitizer; ##EQU00011## is the peak absorption wavelength of the first maximum at long wavelength of the fluorescent emitter. and each of said values ​​is calculated in electron volts. A composition comprising:

20. 20. The composition according to claim 19, characterized in that the composition comprises at least one further material selected from the group of electron transport materials, electron injection materials, electron blocking materials, hole transport materials, hole injection materials, hole blocking materials, n-dopants, p-dopants, quantum materials, host or matrix materials, wide band gap materials, phosphorescent emitters, fluorescent emitters or emitters having delayed fluorescence.

21. 21. A formulation comprising the composition of claim 19 or 20 and at least one solvent.

22. 21. An electronic device comprising at least one composition according to claim 19 or 20.

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