KR20200022010A - Homogeneous mixture - Google Patents

Abstract

The present application relates to a method of preparing a homogeneous composition comprising at least two vaporizable organic compounds, the method comprising mixing the compounds under heating and rotation in a rotatable vessel. The invention further relates to the use of such a homogeneous composition for the manufacture of an electronic device and to an electronic device comprising the homogeneous composition in at least one functional organic layer.

Description

Homogeneous mixture

The present invention relates to a process for producing a homogeneous composition comprising at least two vaporizable organic compounds, to the use of such a homogeneous composition for the manufacture of an electronic device and to an electronic device comprising the homogeneous composition in at least one layer.

In the context of the present application an electronic device is understood to mean what is called an organic electronic device, containing an organic semiconductor material as a functional material. More specifically, these devices are understood to mean organic electroluminescent (EL) devices, in particular organic light emitting diodes (OLEDs).

General structures and modes of operation of organic electroluminescent devices are known to those skilled in the art and are described, for example, in US 4539507, US 5151629, EP 0676461 and WO 98/27136. In general, organic electroluminescent devices contain spaced apart electrodes separated by one or more layers comprising organic compounds, which form so-called organic light emitting structures and, in response to the application of a potential difference across the electrodes, typically Emits light.

Within this application, any layer of an organic electronic device comprising at least one organic compound as a functional material will also be referred to as an "organic layer" or "(poly) functional organic layer", which terms are used interchangeably. The term "multifunctional" denotes that the organic layer comprises one or more organic materials of different functionality.

Recently, preferred electronic devices have been constructed using thin film deposition techniques. For example, using an anode as a device support, organic light emitting structures have been deposited as a combination of a plurality of organic thin films, where each organic layer has a different functionality within the electronic device followed by deposition of a cathode.

In order to increase the performance, in particular the lifetime, the efficiency and the operating voltage of the electronic device, an organic layer composed of a plurality of organic compounds, for example an organic layer in which different host (or matrix) materials are mixed (eg host + co- It is standard knowledge to use an organic layer consisting of a host or hole transport material (HTM) + electron transport material (ETM)), or one or more host materials in which dopants are dispersed.

In principle, there are two possibilities to implement this multifunctional organic layer deposition concept. According to the first concept, different organic materials to be deposited are provided as independently controlled evaporation sources (also called "evaporation boats"). Each organic material is then evaporated from its respective evaporation source, for example "Simplified, yellow, organic light emitting diode by co-evaporation of premixed dye molecules" by Steinbacher et al., Organic Electronics (2011), 12 , 911-915 Thin film deposition, as described, is condensed on a substrate, such as an anode or a cathode, to form a multifunctional organic layer. However, this "co-evaporation" or "co-deposition" process has at least two disadvantages: i) It is difficult and time-consuming to precisely control the desired deposition rate of each organic material, and ii) co-evaporation in terms of material utilization It is relatively wasteful.

According to a second concept, different organic materials to be deposited are first mixed (so-called "premixed" or "premixing"). There is provided a single evaporation source comprising the resulting mixture. The single evaporation source is then heated for a time and temperature sufficient to evaporate and deposit the organic compound onto the substrate to form a multifunctional organic layer. This process, known as "preliminary mixing-evaporation", advantageously does not require precise control of multiple independent evaporation sources, is not a waste in terms of material use, and enables simple and fast evaporation deposition and device fabrication. It is also possible to apply or coat a thin organic layer on a substrate, for example an anode or a cathode, so that different organic materials are distributed substantially uniformly throughout the layer.

Combinations of two or more host materials useful in organic light emitting devices and suitable for premixed evaporation from a single evaporation source are described in WO 2011/136755 A1.

EP 1 274 136 A2, EP 1 337 132 A1 and EP 1 454 736 A2 provide a mixture before mixing or blending powders of organic host and dopant materials to agglomerate the mixture into solid compacted pellets, the pellets of the OLED It has been reported to be used in a thermal physical vapor deposition (PVD) source for making an organic layer on a structure forming part.

EP 1 156 536 A2 relates to a method for producing an organic electroluminescent device, which describes premixing a host material and a luminescent dopant material in a desired proportion and then melting the mixture. The predoped material is then used for evaporation deposition of the doped release layer.

WO 2004/070787 A2 reports a method for producing multifunctional thin films by evaporation from a single evaporation source. The method includes melting and premixing different organic materials, such as matrix materials and dopants using high temperature and high pressure processes, and depositing organic materials on the surface of the substrate. The premix is carried out by stirring the material mixture with a stir bar.

However, using a stir bar or stirrer to premix the melt has several disadvantages. Firstly, only local agitation of the mixture or melt can take place to prevent thorough mixing of the organic materials used. As a result, the mixing performance or the mixing quality can be lowered. Second, depending on the viscosity of the melt, a stir bar or stirrer may require high rotational force. Upon cooling, the viscosity of the mixture will increase and the stirrer will eventually shut off. Based on the zone melting principle, the remaining melt can be prevented from mixing (ie separated) when solidification is started without stirring. In addition, due to the insertion of the stir bar or stirrer into the mixture or melt, there is a high risk of contaminating the premixed material. In addition, the application of a stir bar or stirrer makes it more difficult to have an inert system for premixing and evaporation.

In order to manufacture electronic devices with adequate lifetimes and efficiencies, it is important for organic materials to be evaporated and deposited uniformly and consistently, and to maintain the proportion of the material of the initial mixture in the resulting deposited organic layers. To achieve this, a homogeneous and homogeneous mixed composition must be used for evaporation deposition.

For a method for producing a more homogeneously mixed homogeneous composition, in particular a composition that can be vacuum deposited, to produce a more homogeneously mixed homogeneous composition, especially by premixed evaporation for the production of electronic devices with suitable lifetimes and efficiencies. Industrial needs are still required and this method overcomes the shortcomings of the latest technology.

It is therefore an object of the present invention to provide a method for producing a homogeneous composition, in particular a composition which can be vacuum deposited, which overcomes the disadvantages of the state of the art. In particular, it is an object of the present invention to provide a composition which can be used for premix-evaporation in the manufacture of electronic devices with high purity and improved homogeneity and with improved lifetime and efficiency.

This object is solved by a method for preparing a homogeneous composition, in particular a composition which can be vacuum deposited, which comprises at least two vaporizable organic compounds, which method comprises:

a. Providing a rotatable container containing said at least two vaporizable organic compounds;

b. Heating the vessel to form a melt and simultaneously rotating the vessel in a continuous manner to homogenize the melt.

The inventors have surprisingly found that compositions with high purity and improved homogeneity can be obtained by the process according to the invention. It has also been found that the method according to the invention is particularly applicable to producing homogeneous compositions which can be vacuum deposited using a single evaporation source, in particular for manufacturing electronic devices. The inventors have further added that electronic devices in which one or more organic layers have been deposited by evaporation deposition using the premixed homogeneous composition of the present invention exhibit improved properties in terms of efficiency and lifetime compared to using mixtures of the prior art. Can be shown as

Advantageously, the process according to the invention prevents local agitation and mixing of the composition, thus enabling thorough mixing of the composition, so that a composition with high homogeneity can be obtained. In addition, since the melt does not require the insertion of an agitator or stir bar, premixing of the organic compounds is carried out in an inert system to prevent unwanted contamination of the composition during the premixing.

As used herein, a "composition" is a material system or mixture composed of two or more different (organic) materials that are mixed but not chemically bound, ie, represent a physical combination of two or more materials whose identities are retained. Accordingly, the terms "composition" and "mixture" below will be used interchangeably.

As used herein, a "homogeneous composition" is a type of composition or mixture in which two different (organic) materials are uniformly distributed at the molecular level and constitute one phase. Accordingly, the homogeneous composition or mixture has the same proportions of components over a given sample and all parts of the composition or mixture have the same properties.

Within the framework of the invention, the homogeneous composition is preferably a composition comprising at least two different vaporizable organic compounds, wherein the standard deviation σ of the proportion of the compound after premixing is compared to the initial proportion of these compounds (ie , Relative to the proportion of these compounds in the initial mixture). For example, the standard deviation σ is less than 0.9%, 0.8%, 0.7%, 0.6% or 0.5%, more preferably less than 0.4%, more preferably less than 0.3% and most preferably 0.2% Is less than

The process according to the invention is particularly suitable for the production of homogeneous compositions which can be vacuum deposited, in particular electronic devices, preferably organic electroluminescent (EL) devices, characterized in that one or more layers are coated by a sublimation process. . In this case, the homogeneous composition is applied onto the substrate by evaporation deposition from a single evaporation source.

Preferably, at least two different vaporizable organic compounds comprise a host or matrix material, an emission material, an electron injection material, an electron transport material, an electron blocking material, a broadband gap material, a hole injection material, a hole transport material, a hole blocking material, And are independently selected from the group consisting of an exciton blocking material, an n-dopant or a p-dopant, and any combination thereof. In this application, these materials are understood to mean functional organic compounds or materials.

Accordingly, the expression “at least two different vaporizable organic compounds” as used herein refers to organic compounds, for example host materials and broadband gaps, in which the vaporizable organic compounds or materials that must be part of a homogeneous composition each have different functionality. It is understood that it can be selected from materials, and / or organic compounds having the same functionality, for example only host materials, only matrix materials or electron injection materials.

As used herein, the term “vaporizable organic compound” can be evaporated in vacuo and consequently used in a vacuum deposition process to deposit thin films or layers, especially organic layers, in electronic devices, preferably in organic electroluminescent devices. It is understood to mean any functional organic compound or material that can be.

In a preferred embodiment of the present invention, at least two vaporizable organic compounds for preparing the homogeneous composition are host materials.

In this case, the premixed homogeneous composition is preferably used in the emitting layer of the electronic device in combination with one or more emitting compounds, preferably in the phosphorescent emitting layer of the phosphorescent organic electroluminescent device, which adds one or more phosphorescent emitting compounds. It characterized by including as. In this case, the homogeneous composition comprising at least two vaporizable host materials acts as a matrix material of the phosphorescent emitter and does not participate or substantially participate in the luminescence itself. In the literature, the term "matrix material" is used very often instead of "host material", especially when the host material is used in combination with a phosphorescent emitting compound.

The system comprising a plurality of host or matrix materials (“mixed matrix system”) preferably comprises two or three different host or matrix materials, more preferably two different host or matrix materials. Preferably, in this case, one of the two materials is a (host or matrix) material with hole transport properties, i.e. a material that contributes greatly to hole transport, and the other is a (host or matrix) material with electron transport properties, That is, it is a material which greatly contributes to electron transport. One source of more detailed information on mixed matrix systems is the application WO 2010/108579.

Host materials, which are preferably useful for fluorescent emitting compounds, which can be used in premixing to prepare the light emitting layer, include materials of various material classes. Preferred host materials are of the family of oligoarylenes (for example 2,2 ', 7,7'-tetraphenylspirobifluorene or dinaphthylanthracene according to EP 676461), in particular of oligoarylenes containing fused aromatic groups Family, oligoarylenevinylenes (for example DPVBi or Spiro-DPVBi according to EP 676461), polypodal metal complexes (for example according to WO 2004/081017), hole-conducting compounds (for example WO 2004/058911), electron-conducting compounds, in particular ketones, phosphine oxides, sulfoxides, and the like (eg according to WO 2005/084081 and WO 2005/084082), atropisomers (eg WO 2006 / 048268), boronic acid derivatives (for example according to WO 2006/117052) or benzanthracene (for example according to WO 2008/145239). Particularly preferred matrix materials are selected from the class of oligoarylenes including olphthalarylenes, naphthalenes, anthracenes, benzanthracenes and / or pyrenes or atropisomers of these compounds, oligoarylenevinylenes, ketones, phosphine oxides and sulfoxides. Very particularly preferred matrix materials are selected from the class of oligoarylenes comprising anthracene, benzanthracene, benzophenanthrene and / or pyrene or atropisomers of these compounds. In the context of the present invention oligoarylene will be understood to mean compounds in which at least three aryl or arylene groups are bonded to one another. Anthracene derivatives disclosed in WO 2006/097208, WO 2006/131192, WO 2007/065550, WO 2007/110129, WO 2007/065678, WO 2008/145239, WO 2009/100925, WO 2011/054442 and EP 1553154, and EP 1749809 Preference is further given to the pyrene compounds disclosed in EP 1905754 and US 2012/0187826.

Preferred fluorescent emitting compounds which can be premixed with the host material are selected from the arylamine class. Arylamines or aromatic amines are understood in the context of the present invention to mean compounds containing three substituted or unsubstituted aromatic or heteroaromatic ring systems bonded directly to nitrogen. Preferably, at least one of these aromatic or heteroaromatic ring systems is a fused ring system, more preferably having at least 14 aromatic ring atoms. Preferred examples thereof are aromatic anthraceneamine, aromatic anthracenediamine, aromatic pyrenamine, aromatic pyrendiamine, aromatic chryseneamine or aromatic chrysenediamine. Aromatic anthraceneamines are understood to mean compounds in which the diarylamino group is bonded directly to the anthracene group, preferably at the 9 position. Aromatic anthracenediamine is understood to mean a compound in which two diarylamino groups are bonded directly to an anthracene group, preferably at the 9,10 position. Aromatic pyrenamines, pyrendiamines, chryseneamines and chrysenediamines are similarly defined, wherein the diarylamino groups in the pyrene group are preferably bonded in the 1 or 1,6 position. Further preferred release compounds are indenofluoreneamine or -diamine (for example according to WO 2006/108497 or WO 2006/122630), benzoindenofluoreneamine or -diamine (for example according to WO 2008/006449 ), And indenofluorene derivatives having dibenzoindenofluoreneamine or -diamine (for example according to WO 2007/140847), and fused aryl groups disclosed in WO 2010/012328. Likewise preferred are the pyrenarylamines disclosed in WO 2012/048780 and WO 2013/185871. Likewise preferred are benzoindenofluoreneamines disclosed in WO 2014/037077, benzofluoreneamines disclosed in WO 2014/106522 and extended benzoindenofluorenes disclosed in WO 2014/111269.

The term "phosphorescent emitting compound" is typically influenced by the emission of light through a spin-inhibited transition, for example from a excited triplet state or a state with higher order spin quantum numbers, for example a five state. Compound.

Suitable phosphorescent emitting compounds (= triple emitters), when particularly suitably excited, emit light, preferably in the visible region, and also more than 20, preferably more than 38, and less than 84, more preferably 56 Compounds containing at least one atom of greater than to less than 80 atomic numbers. Preference is given to phosphorescent emitting compounds which include compounds containing copper, molybdenum, tungsten, rhenium, ruthenium, osmium, rhodium, iridium, palladium, platinum, silver, gold or europium, in particular iridium, platinum or copper To use. In the context of the present invention, all luminescent iridium, platinum or copper complexes are considered to be phosphorescent emitting compounds.

Examples of the above-mentioned emitting compounds, which can be premixed with the matrix material, are described in the applications WO 00/70655, WO 01/41512, WO 02/02714, WO 02/15645, EP 1191613, EP 1191612, EP 1191614, WO 05/033244. , WO 05/019373 and US 2005/0258742. In general, all phosphorescent complexes known to those skilled in the art of organic electroluminescent devices and used in phosphorescent OLEDs according to the prior art are suitable. One skilled in the art can also use additional phosphor complexes in combination with compounds of formula (I) in organic electroluminescent devices without practicing the techniques of the present invention. Further examples are listed in the following table.

Preferred host or matrix materials for phosphorescent emitting compounds, which can be premixed and used to prepare the emitting layers of phosphorescent organic electroluminescent devices, are for example aromatic ketones, aromatic phosphine oxides or aromatic sulfoxides or sulfones (eg For example according to WO 2004/013080, WO 2004/093207, WO 2006/005627 or WO 2010/006680), triarylamines, carbazole derivatives (for example CBP (N, N-biscarbazolylbiphenyl) or Carbazole derivatives described in WO 2005/039246, US 2005/0069729, JP 2004/288381, EP 1205527 or WO 2008/086851), indolocarbazole derivatives (for example according to WO 2007/063754 or WO 2008/056746) Indenocarbazole derivatives (for example according to WO 2010/136109, WO 2011/000455 or WO 2013/041176), azacarbazole derivatives (for example EP 1617710, EP 1617711, EP 1731584, JP 2005/347160). ), Bipolar matrix material (eg According to WO 2007/137725), silanes (for example according to WO 2005/111172), azaborole or boronic acid esters (for example according to WO 2006/117052), triazine derivatives (for example WO 2010 / 015306, according to WO 2007/063754 or WO 2008/056746), zinc complexes (for example according to EP 652273 or WO 2009/062578), diazasilol or tetraazaylol derivatives (for example according to WO 2010/054729) ), Diazaphosphol derivatives (eg according to WO 2010/054730), crosslinked carbazole derivatives (eg US 2009/0136779, WO 2010/050778, WO 2011/042107, WO 2011/088877 or WO 2012/143080) ), Triphenylene derivatives (for example according to WO 2012/048781), or lactams (for example according to WO 2011/116865 or WO 2011/137951).

In another preferred embodiment, at least two vaporizable organic compounds used to prepare the homogeneous composition are electron transport materials.

In this case, the homogeneous composition is preferably used for the electron transport layer, the hole blocking layer or the electron injection layer of the electronic device, preferably the organic electroluminescent device.

The electron transport layer according to the present application is a layer having an electron transport function between the anode and the emission layer.

The electron transport material that can be used in pre-mixing with the electron transport layer of the organic electroluminescent device as defined above can be any material used in the prior art as the electron transport material in the electron transport layer. Particularly suitable are aluminum complexes such as Alq ₃ , zirconium complexes such as Zrq ₄ , lithium complexes such as Liq, benzimidazole derivatives, triazine derivatives, pyrimidine derivatives, pyridine derivatives, pyrazine derivatives, quinoxaline Derivatives, quinoline derivatives, oxadiazole derivatives, aromatic ketones, lactams, boranes, diazaphosphol derivatives and phosphine oxide derivatives. Further suitable materials are derivatives of the abovementioned compounds as described in JP 2000/053957, WO 2003/060956, WO 2004/028217, WO 2004/080975 and WO 2010/072300.

In another preferred embodiment, the at least two vaporizable organic compounds used to prepare the homogeneous composition are hole transport materials.

In this case, the homogeneous composition is preferably used for the hole transport layer, the hole blocking layer or the hole injection layer of the electronic device, preferably the organic electroluminescent device.

The hole transport layer according to the present application is a layer having a hole transport function between the anode and the emissive layer.

The hole injection layer and the electron blocking layer are understood to be specific embodiments of the hole transport layer in the context of the present application. The hole injection layer is, in the case of a plurality of hole transport layers between the anode and the emissive layer, a hole transport layer directly adjacent to the anode or separated only therefrom by a single coating of the anode. The electron blocking layer is a hole transport layer directly adjacent to the emission layer on the anode side in the case of a plurality of hole transport layers between the anode and the emission layer.

Preferred examples of hole transport materials which can be used premixed with the hole transport layer, electron blocking layer or hole injection layer of the electroluminescent device as defined above are indenofluoreneamines and derivatives (for example WO 06/122630 or WO 06/100896), amine derivatives disclosed in EP 1661888, hexaazatriphenylene derivatives (for example according to WO 01/049806), amine derivatives with condensed aromatics (for example according to US Pat. No. 5,061,569), WO Amine derivatives disclosed in 95/09147, monobenzoindeno-fluoreneamines (for example according to WO 08/006449) or dibenzoindenofluoreneamines (for example according to WO 07/140847). Suitable hole transport and hole injection materials are also described in JP 2001/226331, EP 676461, EP 650955, WO 01/049806, US Patent 4,780,536, WO 98/30071, EP 891121, EP 1661888, JP 2006/253445, EP 650955, WO 06 / 073054 and U.S. Patent 5,061,569, derivatives of the compounds shown above.

In another preferred embodiment, one of the at least two vaporizable organic compounds is a host material, preferably a host material having electron transport properties or a host material having hole transport properties, most preferably a host material having electron transport properties And the other is a broadband gap material. It is also conceivable within the framework of the present invention to prepare a homogeneous mixture of at least one host material having electron transport properties and at least one host material having hole transport properties.

As used herein, wide band gap material will be understood to mean a material characterized by having a band gap of at least 3.5 eV as disclosed in US 7,294,849. The term "band gap" refers to the distance between the energy levels of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of a compound. Such a system exhibits particularly advantageous performance data for electroluminescent devices.

In another preferred embodiment, one of the at least two vaporizable organic compounds used to prepare the homogeneous composition is an electron transport material and the other is an n-dopant, or one of the at least two vaporizable organic compounds is a hole The transport material and the other is p-dopant.

The p-dopant used according to the invention is preferably an organic electron donor compound capable of reducing one or more other compounds in the mixture. Preferred examples of n-dopants are W (hpp) ₄ and further electron-floating metal complexes, P = N-compounds (eg WO 2012/175535 A1, WO 2012/175219 A1), naph according to WO 2005/086251 A2. Styrenecarbodiimide (eg WO 2012/168358 A1), fluorene (eg WO 2012/031735 A1), radicals and biradicals (eg EP 1837926 A1, WO 2007/107306 A1), pyridine (eg EP 2452946 A1, EP 2463927 A1), N-heterocyclic compounds (eg WO 2009/000237 A1) and acridine and phenazine (eg US 2007/145355 A1).

The p-dopant used according to the invention is preferably an organic electron acceptor compound capable of oxidizing one or more other compounds in the mixture. Preferred examples of p-dopants are F ₄ -TCNQ, F ₆ -TNAP, NDP-2 (Novaled), NDP-9 (Novaled), quinones (e.g. EP 1538684 A1, WO 2006/081780 A1, WO 2009). / 003455 A1, WO 2010/097433 A1), radioactive material (for example EP 1988587 A1, US 2010/102709 A1, EP 2180029 A1, WO 2011/131185 A1, WO 2011134458 A1, US 2012/223296 A1), S- Containing transition metal complexes (eg WO 2007/134873 A1, WO 2008/061517 A2, WO 2008/061518 A2, DE 102008051737 A1, WO 2009/089821 A1, US 2010/096600 A1), bisimidazoles (eg WO 2008/138580 A1), phthalocyanines (eg WO 2008/058525 A2), bora-tetraazaptantans (eg WO 2007/115540 A1) fullerenes (eg DE 102010046040 A1) and main group halides (eg WO 2008/128519 A2).

In principle, all different kinds of functional vaporizable organic compounds as described above can be premixed using the process according to the invention to form a homogeneous composition.

The proportion of the organic material to be premixed is not particularly limited. This may be in the range of 99.9: 0.1 to 0.1: 99.9 when the two kinds of organic materials are premixed using the method of the present invention.

The vaporizable organic compound to be premixed is preferably provided in a rotatable container in a solid form, such as, but not limited to, powder, pellets, particles, granules, spheres, chips, shards or needles and the like. This means that the desired amount of each solid material is first provided in a rotatable vessel, preferably in a single evaporation source, to form a solid initial mixture.

Then, in order to premix different vaporizable organic compounds according to the process of the invention, the initial mixture is applied by heating, and the vessel containing the melt is continuously rotated to uniformly distribute the used compounds to homogenize the melt. Let's do it. According to the process of the invention, it is preferred that the rotation is already carried out during heating if the compound to be premixed has not yet melted, ie if the melt has not yet formed.

In order to increase the homogeneity of the composition (ie the distribution of different materials in the melt), the heating and rotation of the vessel containing the melt comprising at least two vaporizable organic compounds is preferably carried out for at least 1 hour after the melt is formed. , Preferably for 1 to 5 hours, more preferably for 2 to 3 hours.

In another preferred embodiment of the process according to the invention, heating and rotation are carried out under reduced pressure, preferably in the range of 10 ⁻³ to 10 ⁻⁸ bar, more preferably in the range of 10 ⁻⁵ to 10 ⁻⁷ bar.

Applying vacuum during heating and melting of at least two vaporizable organic compounds results in a lower temperature gap between the melting points of the different organic compounds to be premixed, so that organic compounds having different physical properties, in particular with different melting points, are also homogeneous It has the advantage that it can be used to prepare the composition. Thus, the process according to the invention is not limited to mixing organic compounds with similar physical properties, especially with regard to their melting point. In addition, the application of a vacuum accelerates the melting, thereby accelerating the entire premixing process.

The temperature applied during heating and rotation depends on several factors: the melting point of the organic compound to be premixed, the vacuum level applied and the mixing ratio of the components. However, one skilled in the art knows which temperature level should be set during the heating step to melt the vaporizable organic compound to be premixed. Preferably, the temperature is set at 100-500 ° C. under a vacuum level of 10 ⁻⁵ −10 ⁻⁷ bar.

The rotational speed of the vessel during heating and mixing is not particularly limited. However, in order to ensure proper mixing and homogenization of the melt, the rotational speed of the vessel is preferably set to 2 to 10 rpm, more preferably 4 to 8 rpm. If the rotational speed of the vessel during heating and mixing is within this range, the best mixing performance and mixing quality for homogeneity is achieved within a reasonable timeframe.

In another preferred embodiment of the method according to the invention, the container containing the mixture of at least two vaporizable organic compounds rotates about an axis of rotation arranged substantially horizontally.

In the case of vertical rotation, gravity can interfere with the uniformity of the mixture as the material with the higher density decreases in the melt and the material with the lower density rises. This gravitational effect is much less pronounced for horizontal rotation and therefore does not have a significant effect on the uniformity of the mixture, resulting in more thorough mixing.

As used herein, "substantially horizontally arranged" means that the axis of rotation of the rotating container does not need to be strictly horizontally positioned, i.e. the deflection angle α (α = 0 °) of the axis of rotation away from the horizontal alignment is zero. It may not be. Preferably α = ≦ ± 45 °, more preferably ≦ ± 30 °, even more preferably ≦ ± 20 °. Especially preferably, α = ≦ 10 °, most preferably α = 0 °. The deviation at α = 0 ° does not interfere with the performance of the mixing device.

Upon cooling, the viscosity of the mixture will increase and the residual melt will demix when solidification begins without rotation or stirring based on the zone melting principle. As mentioned above, conventional stirrers will eventually be blocked due to an increase in viscosity. In contrast, by using a rotatable container according to the method of the present invention, rotation and mixing can be performed even upon cooling of the mixture. Thus, according to the method of the present invention, it is preferred that the rotation is still performed during the cooling period to prevent any demixing process.

Thus, in a preferred embodiment of the method according to the invention, the method further comprises the following steps

c. Cooling the homogenized melt under rotation.

Preferably, the premixed homogenized melt can be cooled to room temperature to collect the homogeneous composition from the mixing chamber. The cooling rate and the cooling time are not particularly limited. The cooling time may vary depending on the operating temperature.

In the following, an exemplary rotatable mixing device capable of producing a homogeneous composition according to the method of the invention is described with reference to FIG. 1, but is not to be considered as limiting the scope of the invention. Similar devices are reported in WO2015 / 022043, and details of the following description including the advantages of different embodiments can be reviewed from this source.

1 is a schematic diagram of a rotatable mixing device used to premix at least two vaporizable organic compounds in accordance with the method of the present invention.

The mixing device comprises a heating oven 1, a mixing unit 2, a rotary coupling 3 and a high vacuum pump 4.

The oven 1 can be heated by any state of the art heating mechanism. Preferably an indirect heating mechanism is used, for example hot gas or air. The temperature can be controlled by any suitable type, for example a thermocouple, and can be controlled by a controller (not shown). The hot air of the oven is evenly distributed to avoid any hot spots with respect to the material to be melted and premixed. For example, a stainless steel pan in front of the heater can be used to distribute heat evenly in the oven 1, which is guaranteed even under rotation. The oven may include a window for monitoring melt behavior and controlling heating temperature (not shown).

The connection between the units 2, 3 and 4 is generally sealed. The overall setting is preferably horizontal (α = 0 ° in FIG. 1), but the deviation from this angle does not interfere with the performance of the mixing device as described above. The mixing unit 2 is filled with a desired amount of at least two different vaporizable organic materials. After the melting process, the resulting premix can be separated from the mixing unit 2. The material of the mixing unit 2 is not particularly limited. However, glass articles are the most suitable material because transparent chambers are preferred for monitoring melt behavior and controlling heating temperatures.

The rotary coupling 3 is a high vacuum drive source which drives the rotation of the mixing unit 2 while maintaining a high vacuum seal between the rotary part of the mixing unit 2 and the static part of the high vacuum pump 4. The direction of rotation clockwise or counterclockwise does not affect the efficiency of the mixing process. The drive source may be of any suitable size, shape, configuration and / or type. For example, the drive source may be a commercially available rotary motor coupled with the magnetic fluid seal.

Any suitable type of vacuum pump 4 can be used to apply a vacuum to the mixing unit 2. A cold trap (not shown) can be located near the vacuum pump 4 in a high vacuum connection.

Other suitable rotatable mixing devices are also disclosed in WO2015 / 022043.

It is envisioned by the invention that the rotatable mixing device is or is part of a vacuum deposition device or an evaporation system. In this case, the mixing unit 2 represents an evaporation source or a boat and the homogenized melt is not cooled after premixing.

As mentioned above, the process according to the invention can produce a composition comprising at least two vaporizable organic compounds having high purity and homogeneity, wherein the homogeneity is premixed compared to the proportion of the compound in the initial mixture. It is then defined by the standard deviation of the proportion of compounds included in the composition.

Accordingly, the subject of the invention is also a homogeneous composition comprising at least two vaporizable organic compounds obtainable or obtained by the process according to the invention. In particular, the resulting homogeneous composition is characterized in that the standard deviation (σ) of the proportion of the compound after premixing is less than 1.0% compared to the initial proportion of the compound (ie, compared to the proportion of these compounds in the initial mixture). For example, the standard deviation (σ) is less than 0.9%, 0.8%, 0.7%, 0.6% or 0.5%, more preferably less than 0.4%, more preferably less than 0.3%, most preferably Less than 0.2%.

As mentioned above, the compositions for use in the vacuum deposition method are homogeneous to ensure uniform and consistent evaporation and deposition of the composition and to maintain the proportion of organic material in the initial mixture in the resulting organic layer deposition, especially where the composition is a single source of evaporation. It is preferable when vaporizing from to deposit a (poly) functional organic layer on an electronic device. As will be appreciated by the inventors (see experimental section below), using the homogeneous composition according to the invention in the manufacturing process of an electronic device, preferably an organic electroluminescent (EL) device, such as an organic light emitting diode (OLED), Device performance is improved in terms of lifetime and efficiency.

It is therefore an object of the present invention to evaporate the composition from a single evaporation source, thereby producing a homogeneous composition according to the invention or a homogeneous composition prepared according to the method for the production of an electronic device, preferably an organic electroluminescent (EL) device. It is further achieved by using.

In particular, depending on the vaporizable organic compounds chosen for the premixing, ie their functionality, the homogeneous compositions of the invention are produced by the evaporation deposition of the homogeneous composition using a single Can be used to prepare functional organic layers

In addition to the cathode, anode and emissive layer, the organic electroluminescent device may also comprise additional functional layers. This is, for example, in each case one or more hole injection layers (HIL), hole transport layers (HTL), hole blocking layers (HBL), electron transport layers (ETL), electron injection layers (EIL), electron blocking layers, exciton blocking Layer (EBL), interlayer, charge generating layer (IDMC 2003, Taiwan; Session 21 OLED (5), T. Matsumoto, T. Nakada, J. Endo, K. Mori, N. Kawamura, A. Yokoi, J. Kido , Multiphoton Organic EL Device Having Charge Generation Layer ) and / or organic or inorganic p / n junctions.

The invention therefore also relates to a layer obtainable by evaporating a homogeneous composition according to the invention or a homogeneous composition prepared according to the process of the invention from a single evaporation source. Preferably, the layer thus obtained is a functional organic layer in the organic light emitting structure of the organic electroluminescent device.

The order of the layers of the organic electroluminescent device in which one or more layers can be applied by evaporation deposition using the homogeneous composition of the invention is preferably as follows: anode / hole injection layer / hole transport layer / optional additional hole transport layer / Optional electron blocking layer / emitting layer / optional hole blocking layer / electron transporting layer / electron injection layer / cathode. Additional layers may be present in the organic electroluminescent device.

Accordingly, the present invention also provides an electronic device, preferably an organic electric field, comprising at least one layer obtainable by evaporation deposition of a homogeneous composition of the invention, or a homogeneous composition prepared according to the method of the invention, using a single evaporation source. A light emitting (EL) device, wherein the layer is preferably an electron transport layer (ETL), a hole blocking layer (HBL), a hole transport layer (HTL), an electron blocking layer (EBL), a hole injection layer (HIL) electron injection layer (EIL) and emissive layer (EML).

More preferably, at least one layer is selected from EML, EIL or ETL, most preferably EML.

Electronic devices comprising at least one layer obtainable by evaporation deposition of a homogeneous composition of the invention or a homogeneous composition prepared according to the method of the invention using a single evaporation source are preferably organic light emitting diodes (OLEDs), polymer light emitting Diodes (PLEDs), organic light emitting transistors (OLET), organic light emitting electrochemical cells (OLEC), organic field quench devices (OFQD), organic light emitting electrochemical transistors (OLEET), organic field effect transistors (OFETs), thin film transistors (TFTs) ), Organic solar cells (OSC), organic laser diodes (O-lasers), organic integrated circuits (OIC), radio frequency identification (RFID) tags, photodetectors, sensors, logic circuits, memory elements, capacitors, charge injection layers, Schottky diodes, planarization layers, antistatic films, conductive substrates or patterns, photoconductors, electrophotographic elements, organic solar concentrators, organic spintronic divas And organic plasmon-emitting device to scan (OPED), more preferably OLET, OLED, OLEC, OFQD and O- laser, most preferably selected from the OLED.

As mentioned above, the electronic device according to the invention is characterized in that one or more layers are coated by a vacuum deposition process using a sublimation and condensation process. In this case, the premixed material composition is fed by deposition in a vacuum sublimation system at an initial pressure of less than 10 ⁻⁵ mbar, preferably less than 10 ⁻⁶ mbar using a single evaporation source. In this case, however, it is also possible that the initial pressure is even less, for example less than 10 ⁻⁷ mbar.

Likewise preferred is an electronic device characterized in that one or more layers are coated by the OVPD (organic vapor deposition) method or with the aid of carrier gas sublimation. In this case, the premixed material composition is provided to a single source and a pressure of 10 ⁻⁵ mbar to 1 bar is applied.

The invention therefore also relates to a process for manufacturing an electronic device, preferably an OLET, OLED, OLEC, OFQD or O-laser, most preferably an OLED,

a. Providing a substrate,

b. Preparing a homogeneous composition according to the method of the present invention comprising at least two vaporizable organic compounds; And

c. Evaporating the homogeneous composition from a single evaporation source to form a layer on the substrate.

The substrate is preferably an anode or a cathode, the materials of which are known to those skilled in the art. If more than one layer is applied in this way, step b. And c. May optionally be repeated for each additional layer. Thus, in this case the substrate may also be an already deposited layer.

For evaporation of the homogeneous composition in step c, any vacuum deposition process known to the person skilled in the art and described in the literature can be used. The single evaporation source is heated to a sufficient temperature under vacuum and for a time sufficient to evaporate the organic compound onto the substrate surface to form a (poly) functional layer. Those skilled in the art will be able to determine and set conditions and parameters suitable for evaporation within the ordinary knowledge of the art.

The invention is described in more detail below with the aid of examples which are not to be considered as limiting the scope of the invention.

Work example

material

TMM-001 (WO 04/093207, WO 05/054403)

TMM-002 (WO 08/086851)

Both the TMM-293 and TMM-310 are available from Merck KGaA.

Preparation of Premixed OLED Material Compositions

Homogeneous mixtures according to the invention are prepared using the rotary mixing device described above with reference to FIG. 1.

In order to prepare the premixed composition, each material which should be part of the homogeneous composition according to the invention is weighted using a precision balance and fed directly into the mixing chamber. The total weight of each mixture is 100 g. The mixing chamber is mounted to the rotary mixing device. The mixing chamber is rotated at a rotational speed of 4 rpm and heated to 250 ° C. under vacuum level 10 ⁻⁵ bar. After melting, rotation and mixing are maintained for 2 hours under these conditions. When mixing is complete, the mixture is cooled to room temperature under rotation. The solidified homogeneous mixture obtained is collected by scratching out.

Example 1:

Preparation of the mixtures A1, A2 and A3

The mixtures A1, A2 and A3 were described above by initially mixing the vaporizable organic compounds TMM-001 (melting point 384 ° C.) and TMM-002 (melting point 305 ° C.) at a ratio of 1/3, 1/1 and 3/1 respectively. As prepared according to the procedure of the invention. The total weight of each mixture is 100 g.

Example 2

Preparation of the mixtures B1, B2 and B3

The mixtures B1, B2 and B3 were described above by initially mixing the vaporizable organic compounds TMM-293 (melting point 343 ° C.) and TMM-310 (melting point 292 ° C.) at a ratio of 1/3, 1/1 and 3/1 respectively. As prepared according to the procedure of the invention. The total weight of each mixture is 100 g.

Comparative Example 1

Preparation of Comparative Mixtures C1, C2 and C3

Comparative mixtures C1, C2 and C3 are prepared according to the procedure described in WO 2004/070787 by initially mixing the vaporizable organic compounds TMM-001 and TMM-002 in ratios 1/3, 1/1 and 3/1 respectively. The total weight of each mixture is 100 g.

Comparative Example 2

Preparation of Comparative Mixtures D1, D2 and D3

Comparative mixtures D1, D2 and D3 are prepared according to the procedure described in WO 2004/070787 by initially mixing the vaporizable organic compounds TMM-293 and TMM-310 in ratios 1/3, 1/1 and 3/1 respectively. The total weight of each mixture is 100 g.

Example 3

Characteristics of the mixture

After premixing 10 samples were collected from each of the mixtures Analyze by high performance liquid chromatography (HPLC). The weight of each sample analyzed is 10 mg. The ratio of compounds determined by HPLC for each sample is compared to the ratio of compounds in the initial mixture. The homogeneity of each mixture is determined by the standard deviation (SD) σ.

The standard deviation (SD) σ is calculated using the following formula.

At the ceremony

x = data value

n is the number of samples.

The analysis results and σ are as shown in Tables 1 to 6.

Table 1. Analytical Data for Mixture-A1 and Comparative Mixture-C1

Mixture-A1 prepared according to the procedure of the present invention using the rotary mixing device associated with the present invention is more homogeneous than comparative mixture-C1 (SD = 1.22).

Table 2. Analytical Data for Mixture-A2 and Comparative Mixture-C2

Mixture-A2 prepared according to the procedure of the present invention using the rotary mixing device associated with the present invention is more homogeneous than comparative mixture-C2 (SD = 0.02).

Table 3. Analytical Data for Mixture-A3 and Comparative Mixture-C2

Mixture-A3 prepared according to the procedure of the present invention using the rotary mixing device associated with the present invention is more homogeneous than Comparative Mixture-C3 (SD = 1.60) (SD = 0.10).

Table 4. Analytical Data for Mixture-B1 and Comparative Mixture-D1

Mixture-B1 prepared according to the procedure of the present invention using the rotary mixing device associated with the present invention is more homogeneous than the comparative mixture-D1 (SD = 1.21) (SD = 0.07).

Table 5. Analytical Data for Mixture-B2 and Comparative Mixture-D2

Mixture-B2 prepared according to the procedure of the present invention using the rotary mixing device associated with the present invention is more homogeneous than comparative mixture-D2 (SD = 2.21) (SD = 0.62).

Table 6. Analytical Data for Mixture-B3 and Comparative Mixture-D3

Mixture-B3 prepared according to the procedure of the present invention using the rotary mixing device associated with the present invention is more homogeneous than comparative mixture-D3 (SD = 1.47).

Thus, all mixtures prepared according to the procedure of the present invention using the above-mentioned rotatable mixing device, regardless of the mixing ratio and whether the premixed vaporizable organic compound has a different melting point, More homogeneous in comparison.

Example 4

Device example:

OLED devices are manufactured according to the following process:

The substrate used is a glass plate coated to a thickness of 50 nm with structured ITO (indium tin oxide). The OLED basically has the following layer structure: substrate / hole injection layer (HIL) / hole transport layer (HTL) / emission layer (EML) / electron transport layer (ETL) / electron injection layer (EIL) and finally the cathode. The cathode is formed by an aluminum layer having a thickness of 100 nm.

All materials are evaporated by thermal deposition in a vacuum chamber. The emissive layer always consists of a premixed host material and emissive dopant (emitter) according to the invention. Similarly, the other layer may also consist of a mixture of two or more materials.

OLEDs are characterized by standard methods.

Data for various OLEDs containing the inventive materials and comparative materials are summarized in Table 13.

Table 7. Device Data for OLED

OLEDs comprising homogeneous mixtures (A1, A2, A3, B1, B2, B3) obtained by the process according to the invention in the emitting layer are premixed mixtures (C1, C2, C3, D1, D2, D3) according to the prior art. ), Both higher efficiency [Cd / A] and improved lifetime [h] as compared to OLEDs.

Claims (19)

A process for preparing a homogeneous composition comprising at least two vaporizable organic compounds, in particular a composition which may be vacuum deposited,
a. Providing a rotatable container containing said at least two vaporizable organic compounds,
b. Heating the vessel to form a melt and simultaneously rotating the vessel in a continuous manner to homogenize the melt. The method of claim 1,
The at least two vaporizable organic compounds include host or matrix materials, emissive materials, electron injection materials, electron transport materials, electron blocking materials, broadband gap materials, hole injection materials, hole transport materials, hole blocking materials, excitone blocking materials, and n-dopant or p-dopant, and any combination thereof. The method according to claim 1 or 2,
And the at least two vaporizable organic compounds are host materials. The method according to claim 1 or 2,
And said at least two vaporizable organic compounds are electron transport materials. The method according to claim 1 or 2,
And said at least two vaporizable organic compounds are hole transport materials. The method according to claim 1 or 2,
One of the at least two vaporizable organic compounds is a host material, preferably a host material having electron transport properties or a host material having hole transport properties, most preferably a host material having electron transport properties, and other One is a broadband gap material. The method according to claim 1 or 2,
Wherein at least one of the at least two vaporizable organic compounds is an electron transport material and the other is an n-dopant. The method according to claim 1 or 2,
One of said at least two vaporizable organic compounds is a hole transport material and the other is a p-dopant. The method according to any one of claims 1 to 8,
The heating and rotating is carried out under reduced pressure of 10 ⁻³ to 10 ⁻⁸ bar. The method according to any one of claims 1 to 9,
The heating and rotation of the vessel after the melt is formed is maintained for at least 1 hour. The method according to any one of claims 1 to 10,
The rotational speed of the container is 2 to 10 rpm, the method of producing a composition. The method according to any one of claims 1 to 11,
Wherein the container rotates about an axis of rotation disposed substantially horizontally. The method according to any one of claims 1 to 12,
The method is
c. Further cooling the homogenized melt obtained in step b under rotation. A homogeneous composition comprising at least two vaporizable organic compounds obtainable or obtained by the process according to any one of claims 1 to 13. Use of a homogeneous composition according to claim 14 or a homogeneous composition prepared according to the method according to any one of claims 1 to 13 for producing an electronic device by evaporating the composition from a single evaporation source. A layer obtainable by evaporating a homogeneous composition according to claim 14 or a homogeneous composition prepared according to the method according to any one of claims 1 to 13 from a single evaporation source. An electronic device comprising at least one layer according to claim 16, comprising:
The layer is preferably an electron transport layer (ETL), a hole blocking layer (HBL), a hole transport layer (HTL), an electron blocking layer (EBL), a hole injection layer (HIL), an electron injection layer (EIL) and an emission layer (EML). The electronic device selected from the group consisting of The method of claim 17,
The device includes an organic light emitting diode (OLED), a polymer light emitting diode (PLED), an organic light emitting transistor (OLET), an organic light emitting electrochemical cell (OLEC), an organic field quench device (OFQD), an organic light emitting electrochemical transistor (OLEET), Organic field effect transistor (OFET), thin film transistor (TFT), organic solar cell (OSC), organic laser diode (O-laser), organic integrated circuit (OIC), radio frequency identification (RFID) tag, photodetector, sensor, Logic circuits, memory elements, capacitors, charge injection layers, Schottky diodes, smoothing layers, antistatic films, conductive substrates or patterns, photoconductors, electrophotographic elements, organic solar concentrators, organic spintronic devices, and organic plasmon emitting devices ( OPED). A method of manufacturing an electronic device according to claim 17 or 18,
a. Providing a substrate,
b. Preparing a homogeneous composition according to the method of any one of claims 1 to 13, comprising at least two vaporizable organic compounds, and
c. Evaporating the homogeneous composition from a single evaporation source to form a layer on the substrate.

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