DE102020131756A1 - Layer system for an organic electronic component - Google Patents

Abstract

The invention relates to a layer system for an organic electronic component, having a first electrode, a second electrode, and at least one photoactive layer and/or at least one fullerene layer, the at least one photoactive layer and/or the at least one fullerene layer between the first electrode and the second electrode is arranged, wherein the at least one photoactive layer and/or the at least one fullerene layer has at least one stabilizer additive, an electronic component with such a layer system with at least one stabilizer additive, and use of a such a layer system with at least one stabilizer additive in an organic electronic component.

Description

The invention relates to a layer system for an organic electronic component, having a first electrode, a second electrode, and at least one photoactive layer and/or at least one fullerene layer, the at least one photoactive layer and/or the at least one fullerene layer between the first electrode and the second electrode is arranged, wherein the at least one photoactive layer has at least one stabilizer additive, an organic electronic component with such a layer system, and use of such a layer system in an organic electronic component.

Electronic components with photoactive layers, in particular LEDs or solar cells, are widely used today. Known solar cells preferably have active layers made of amorphous silicon (a-Si) or CIGS (Cu(In,Ga)(S,Se) ₂ ). Also known are solar cells with organic photoactive layers. The organic photoactive layers can be made up of polymers or small molecules. While polymers are characterized by the fact that they cannot be evaporated and can therefore only be applied from solutions, small molecules can be evaporated.

Organic semiconductors based on small molecules or polymeric compounds are increasingly being used in many areas of the electronics industry. Organic semiconductors are used, for example, in electronic components such as organic field effect transistors (OFETs), organic light-emitting diodes (OLEDs), organic photovoltaic elements (OPVs) and photodetectors. If the organic electronic component is an organic optoelectronic component, such as a solar cell or a photodetector, then the component is suitable for converting light energy into electrical energy, the opposite conversion of electrical energy into light emission having an adverse effect on efficiency. In contrast, OLEDs convert electrical current or voltage signals or electrical energy into light emission.

Organic photovoltaic components, in particular organic solar cells, usually consist of a series of thin layers between two electrodes, which are preferably vapor-deposited in a vacuum or processed from a solution. The electrical contact can be made using metal layers, transparent conductive oxides (TCOs) and/or transparent conductive polymers (PEDOT-PSS, PANI). The vacuum evaporation of the organic layers is advantageous in the production of tandem, triple or multiple solar cells. In tandem or multi-junction solar cells, the individual cells are stacked, with each cell containing at least one absorber layer, sandwiched between two electrodes and usually connected in series, so that the cell producing the lowest current limits the whole system.

The photoactive compounds are typically employed in a mixed layer or two adjacent layers to form donor-acceptor heterojunctions (heterojunctions) within a cell in which at least one donor and/or one acceptor is the light absorbing component. In contrast to silicon-based solar cells, the light in organic solar cells does not directly generate free charge carriers; instead, excitons are initially formed, i.e. externally electrically neutral excited states, in particular bonded electron-hole pairs. These excitons are separated into charge carriers at the donor-acceptor boundary layer in transitions between two adjacent layers or within a photoactive mixed layer, which migrate and thus contribute to the electric current flow.

The efficiency (PCE) of organic solar cells decreases over time as a result of degradation processes caused by the effects of light, heat, oxygen and/or water on the organic electronic materials.

Radical scavengers and/or antioxidants, also known as antioxidants, are widely used additives in polymers and other organic systems to protect them from degradation.

It is known from the prior art to improve the service life of polymer films by adding small amounts of free-radical scavengers. The use of certain UV absorbers suppresses the formation of new radicals. It is known from the prior art to use stabilizers in a layer system for electronic components.

Xu et al. (Nano Energy 34, 2017, 392-398) discloses vitamin C (ascorbic acid) in perovskite cells, with vitamin C being used to stabilize Pb/Sn-based perovskite solar cells. to stabilize methylammonium (MA) or formamidinium (FA) uses ascorbic acid as an effective antioxidant additive to increase the efficiency and stability of Pb/Sn-based perovskite solar cells. Ascorbic acid delays the oxidation of Sn and modulates the crystallization of perovskite through the formation of intermediate complexes.

US20150228925A1 discloses the use of vitamin C as an oxygen scavenging compound in an OLED display using vitamin C in a transport layer.

However, the additives known from the prior art for improving the stability of photoactive layers, in particular photoactive layers processed in vacuo, are not satisfactory.

The invention is therefore based on the object of providing a layer system for an organic electronic component, an organic electronic component with such a layer system, and a use of such a layer system in an organic electronic component, the disadvantages mentioned above not occurring, and in particular one improved stability and/or an increased service life of such a layer system is provided. It is a particular object of the present invention to slow down the degradation of a layer system by slowing down the degradation of the layer system by adding one or more additives, referred to here as stabilizer additives, into the electrically active organic layer system.

The object is solved by the subject matter of the independent claims. Advantageous refinements result from the dependent claims.

mit mindestens einem R1, R2, und/oder R3, einem Polyphenol mit mindestens zwei OH-Gruppen, und/oder mindestens einem R1, R2, und/oder R3 einem sterisch gehinderten Phenol mit mindestens einer sterischen Alkylgruppe, wobei die sterische Alkylgruppe an der alpha-Position verzweigt ist, und mit R4 unabhängig voneinander ausgewählt aus der Gruppe bestehend aus H, OH, Alkyl, und Alkoxy;

mit mindestens einem R1, R2 und/oder R3 einem Polyphenol mit mindestens zwei OH-Gruppen, und/oder mindestens einem R1, R2 und/oder R3 einem sterisch gehinderten Phenol mit mindestens einer sterischen Alkylgruppe, wobei die sterische Alkylgruppe an der alpha-Position verzweigt ist, und mit R4 unabhängig voneinander ausgewählt aus der Gruppe bestehend aus H, OH, Alkyl, und Alkoxy;

mit mindestens einem R1, R2 und/oder R3 einem Polyphenol mit mindestens zwei OH-Gruppen, und/oder mindestens einem R1, R2 und/oder R3 einem sterisch gehinderten Phenol mit mindestens einer sterischen Alkylgruppe, wobei die sterische Alkylgruppe an der alpha-Position verzweigt ist;

mit mindestens einem R1, R2 und/oder R3 einem Polyphenol mit mindestens zwei OH-Gruppen;

mit R5 ausgewählt aus der Gruppe bestehend aus Alkyl, O-Alkyl, S-Alkyl, OH, und einem substituierten oder nicht-substituierten aromatischen homocyclischen oder heterocyclischen 5-Ring oder 6-Ring, wobei der 5-Ring oder 6-Ring bevorzugt weiter annelliert ist; und

wobei der Anteil des mindestens einen Stabilisator-Additivs in der mindestens einen photoaktiven Schicht und/oder der mindestens einen Fulleren-Schicht 0,001 Gew.-% bis 30 Gew.-% beträgt, bevorzugt 0,001 Gew.-% bis 10 Gew.-%, oder bevorzugt 0,1 Gew.-% bis 2 Gew.-%.The object is achieved in particular by providing a layer system for an organic electronic component, having a first electrode, a second electrode, and at least one photoactive layer and/or at least one fullerene layer, the at least one photoactive layer and/or the at least one fullerene layer is arranged between the first electrode and the second electrode, the at least one photoactive layer and/or the at least one fullerene layer having at least one stabilizer additive, the at least one stabilizer additive being selected from the group consisting of:

with at least one R1, R2, and/or R3, a polyphenol having at least two OH groups, and/or at least one R1, R2, and/or R3 a sterically hindered phenol having at least one steric alkyl group, the steric alkyl group on the alpha-position is branched, and with R4 independently selected from the group consisting of H, OH, alkyl, and alkoxy;

with at least one R1, R2 and/or R3 a polyphenol having at least two OH groups, and/or at least one R1, R2 and/or R3 a sterically hindered phenol having at least one steric alkyl group wherein the steric alkyl group is branched at the alpha position and with R4 independently selected from the group consisting of H, OH, alkyl, and alkoxy;

with at least one R1, R2 and/or R3 a polyphenol having at least two OH groups, and/or at least one R1, R2 and/or R3 a sterically hindered phenol having at least one steric alkyl group, the steric alkyl group being in the alpha position is branched;

with at least one R1, R2 and/or R3 a polyphenol having at least two OH groups;

with R5 selected from the group consisting of alkyl, O-alkyl, S-alkyl, OH, and a substituted or unsubstituted aromatic homocyclic or heterocyclic 5-ring or 6-ring, with the 5-ring or 6-ring being preferred further is annulated; and

wherein the proportion of the at least one stabilizer additive in the at least one photoactive layer and/or the at least one fullerene layer is 0.001% by weight to 30% by weight, preferably 0.001% by weight to 10% by weight, or preferably 0.1% to 2% by weight.

In a preferred embodiment of the invention, the proportion of the at least one stabilizer additive in the at least one photoactive layer and/or the at least one fullerene layer is 0.001% by weight to 20% by weight, preferably 0.001% by weight to 10 % by weight, preferably 0.001% by weight to 5% by weight, preferably 0.001% by weight to 2% by weight, preferably 0.01% by weight to 10% by weight, preferably 0.01 % by weight to 5% by weight, preferably 0.01% by weight to 2% by weight, preferably 0.1% by weight to 30% by weight, preferably 0.1% by weight to 20% by weight. %, preferably 0.1% by weight to 10% by weight, preferably 0.1% by weight to 5% by weight, preferably 0.1% by weight to 3% by weight, preferably 0.1% by weight % to 2% by weight, preferably 0.1% by weight to 1% by weight, preferably 1% by weight to 10% by weight, or preferably 1% by weight to 2% by weight %.

In a preferred embodiment of the invention, the at least one stabilizer additive is mixed into the at least one photoactive layer and/or the at least one fullerene layer. In a preferred embodiment of the invention, the at least one stabilizer additive is at least largely homogeneously distributed as a further component in the at least one photoactive layer and/or the at least one fullerene layer, in particular homogeneously in an absorber material or a mixed layer of a donor-acceptor System.

In a preferred embodiment of the invention, the at least one stabilizer additive is at least largely homogeneously distributed in the at least one photoactive layer.

The layer system according to the invention has advantages compared to the prior art. Admixture of specific additives, in particular stabilizer additives, advantageously leads to an increase in the stability of a layer system, and thus also to an increase in an organic electronic component having this layer system, in particular an organic photovoltaic element. Advantageously, the efficiency of the photovoltaic element is not significantly reduced in the process. Advantageously, the efficiency of the photovoltaic element with such a layer system with at least one stabilizer additive is reduced to a lesser extent over time compared to a layer system without at least one stabilizer additive. The addition of at least one stabilizer additive in particular increases the stability of the layer system with respect to moisture, oxygen and/or UV light. The at least one stabilizer additive advantageously stabilizes absorbers in a photoactive layer. The at least one stabilizer additive advantageously stabilizes a fullerene layer (C ₆₀ ). Advantageously, the stabilizer additives can be used at temperatures of up to 150° C., which corresponds to the use and process range of organic solar cells.

A steric alkyl group is understood to mean, in particular, an alkyl group with a branch in the alpha position of the alkyl group.

In a preferred embodiment of the invention, the steric alkyl group is an alkyl group with a branch in the alpha position, preferably an iso-propyl group, an iso-butyl group or a tert-butyl group.

In a particularly preferred embodiment of the invention, at least one photoactive layer, in particular an absorber layer, has at least one stabilizer additive. In an alternative particularly preferred embodiment, at least one absorber layer and at least one HTL layer (hole conduction layer) and/or at least one ETL layer (electron conduction layer) has the at least one stabilizer additive.

The term “photoactive” means in particular a conversion of light energy into electrical energy. In this case, absorber materials in photoactive layers have a large absorption coefficient, at least for a specific wavelength range. Photoactive is preferably understood to mean that absorber materials, in particular at least one donor and/or at least one acceptor, change their charge state and/or their polarization state when exposed to light.

A photoactive layer is understood to mean, in particular, a layer of an electronic component which makes a contribution to the absorption of radiation and/or to the emission of radiation, in particular the photoactive layer absorbs radiation.

The term “homogeneous” is understood to mean in particular an at least largely equal distribution of the at least one stabilizer additive over the entire extent of the at least one photoactive layer and/or the at least one fullerene layer.

In a preferred embodiment of the invention, the at least one photoactive layer has an absorber material. In a particularly preferred embodiment of the invention, the at least one photoactive layer has a donor-acceptor system as absorber material.

For the purposes of the present invention, a stabilizer additive is understood to mean, in particular, an antioxidant, a free-radical scavenger and/or a UV stabilizer.

In a preferred embodiment of the invention, the layer system has at least one photoactive layer with small molecules as the absorber material and the at least one stabilizer additive.

In a preferred embodiment of the invention, the layer system has at least one photoactive layer with small molecules as at least one donor, small molecules as at least one acceptor and the at least one stabilizer additive, the at least one donor and the at least one acceptor being a donor-acceptor -form system.

In the context of the present invention, small molecules are understood as meaning non-polymeric organic molecules with monodisperse molar masses between 100 and 2000 g/mol, which are present in the solid phase under standard pressure (air pressure of the atmosphere surrounding us) and at room temperature. Preferably the small molecules are photoactive.

In a preferred embodiment of the invention, the at least one stabilizer additive has a molar mass of between 100 and 1000 g/mol.

In a preferred embodiment of the invention, the at least one stabilizer additive is introduced at the same time as a further component in addition to an absorber material or a donor-acceptor system during vacuum processing by co-evaporation.

In a preferred embodiment of the invention, the at least one stabilizer additive can be vaporized in vacuo, preferably processed in vacuo, with the at least one stabilizer additive not decomposing or at least largely not decomposing.

In a preferred embodiment of the invention, the at least one stabilizer additive is not polymerized in the at least one photoactive layer, preferably molecules of the stabilizer additive are not polymerized with one another in the at least one photoactive layer and/or molecules of the stabilizer additive are in the at least one photoactive layer is not polymerized with an absorber material.

The layer system according to the invention with at least one stabilizer additive has advantages compared to the prior art. The stability and/or the service life of a layer system with at least one photoactive layer and/or at least one fullerene layer is advantageously increased with the at least one stabilizer additive. Improved stability and/or an increased service life of organic electronic components, in particular of organic solar cells, is advantageously obtained with such a layer system. The at least one stabilizer additive exhibits no or at least largely no absorption of light in the visible range of the electromagnetic spectrum, as a result of which no or at least largely no parasitic absorption takes place. Advantageously, the stabilizer additives can be handled in a vacuum and can be sublimed at least largely non-destructively.

The stabilizer additives advantageously improve the service life of organic solar cells. Advantageously, the at least one stabilizer additive can be added to a photoactive layer of a layer system without impairing its electrical and optical and/or optoelectrical function.

In a preferred embodiment of the invention, the at least one photoactive layer and/or the at least one fullerene layer has a mixture of at least two, preferably at least three, preferably at least four, or preferably a large number of stabilizer additives.

A further development of the invention provides that at least one polyphenol of the groups R1, R2, R3 and/or R5 has at least one steric alkyl group and/or at least one sterically hindered phenol of the groups R1, R2 and/or R3 has at least two steric alkyl groups has, and/or the stabilizer additive A15 to A18 R5 has an aromatic homocyclic or heterocyclic 5-membered ring or 6-membered ring with at least one OH group, preferably at least two OH groups, with one OH group in the beta position of the carbonyl group is arranged from A15 to A18 R5, the stabilizer additive A15 to A18 R5 preferably contains a phenol, particularly preferably a polyphenol.

A development of the invention provides that at least two R1, R2 and/or R3 of the stabilizer additive A1 to A14 are polyphenols and/or at least two R1, R2 and/or R3 of the stabilizer additive A1 to A14 are steric hindered phenols are, preferably at least three, and/or at least one OH group of a polyphenol of the groups R1, R2, R3 and/or R5 in the beta position or gamma position to a carbonyl group, and/or at least one polyphenol or a sterically hindered phenol of the groups R1, R2 and/or R3 of the stabilizer additive is bridged with another polyphenol or sterically hindered phenol by an alkyl group.

mit mindestens zwei R1, R2 und/oder R3 einem Polyphenol mit mindestens zwei OH-Gruppen, oder mindestens zwei sterisch gehinderten Phenolen mit jeweils mindestens einer sterischen Alkylgruppe, bevorzugt jeweils mit mindestens zwei sterischen Alkylgruppen, oder mindestens einem Polyphenol mit mindestens zwei OH-Gruppen und mindestens einem sterisch gehinderten Phenol mit mindestens einer, bevorzugt mindestens zwei sterischen Alkylgruppen, und mit R4 unabhängig voneinander ausgewählt aus H und einer Alkylgruppe;

mit mindestens zwei R1, R2 und/oder R3 einem Polyphenol mit mindestens zwei OH-Gruppen, oder mindestens zwei sterisch gehinderten Phenolen mit mindestens einer sterischen Alkylgruppe, bevorzugt jeweils mit mindestens zwei sterischen Alkylgruppen, oder mindestens einem Polyphenol mit mindestens zwei OH-Gruppen und mindestens einem sterisch gehinderten Phenol mit mindestens einer, bevorzugt mindestens zwei sterischen Alkylgruppen, und mit R4 unabhängig voneinander ausgewählt aus H und einer Alkylgruppe;

mit mindestens zwei R1, R2 und/oder R3 einem Polyphenol mit mindestens zwei OH-Gruppen, oder mindestens zwei sterisch gehinderten Phenolen mit mindestens einer sterischen Alkylgruppe, bevorzugt jeweils mit mindestens zwei sterischen Alkylgruppen, oder mit mindestens einem Polyphenol mit mindestens zwei OH-Gruppen und mindestens einem sterisch gehinderten Phenol mit mindestens einer, bevorzugt mindestens zwei sterischen Alkylgruppen;

mit mindestens einem R1, R2 und/oder R3 einem Polyphenol mit mindestens zwei OH-Gruppen und mindestens einem R1, R2 und/oder R3 einer substituierten oder nicht-substituierten Phenyl-Gruppe, bevorzugt mit mindestens einer Phenyl-Gruppe mit mindestens einer Alkylgruppe, bevorzugt mit mindestens zwei Alkylgruppen, wobei bevorzugt mindestens eine Alkylgruppe eine sterische Alkylgruppe ist, bevorzugt mit einem R1, R2 und/oder R3 einem Polyphenol mit mindestens zwei OH-Gruppen und zwei R1, R2 und/oder R3 einer substituierten oder nicht-substituierten Phenyl-Gruppe;

mit R5 ausgewählt aus der Gruppe bestehend aus Alkyl, O-Alkyl, und einem substituierten oder nicht-substituierten aromatischen homocyclischen oder heterocyclischen 5-Ring oder 6-Ring mit mindestens einer OH-Gruppe, bevorzugt mit einer OH-Gruppe in beta-Position zur Carbonyl-Gruppe; und

Vitamin C.According to a development of the invention, it is provided that the at least one stabilizer additive is selected from the group consisting of:

with at least two R1, R2 and/or R3 a polyphenol having at least two OH groups, or at least two sterically hindered phenols each having at least one steric alkyl group, preferably each having at least two steric alkyl groups, or at least one polyphenol having at least two OH groups and at least one sterically hindered phenol with at least one, preferably min at least two steric alkyl groups, and with R4 independently selected from H and an alkyl group;

with at least two R1, R2 and/or R3 a polyphenol with at least two OH groups, or at least two sterically hindered phenols with at least one steric alkyl group, preferably each with at least two steric alkyl groups, or at least one polyphenol with at least two OH groups and at least one sterically hindered phenol having at least one, preferably at least two, steric alkyl groups, and with R4 independently selected from H and an alkyl group;

with at least two R1, R2 and/or R3 a polyphenol with at least two OH groups, or at least two sterically hindered phenols with at least one steric alkyl group, preferably each with at least two steric alkyl groups, or with at least one polyphenol with at least two OH groups and at least one sterically hindered phenol having at least one, preferably at least two, steric alkyl groups;

with at least one R1, R2 and/or R3 a polyphenol with at least two OH groups and at least one R1, R2 and/or R3 with a substituted or unsubstituted phenyl group, preferably with at least one phenyl group with at least one alkyl group, preferably with at least two alkyl groups, preferably with at least one alkyl group being a steric alkyl group, preferably with one R1, R2 and/or R3 a polyphenol with at least two OH groups and two R1, R2 and/or R3 a substituted or unsubstituted phenyl -Group;

with R5 selected from the group consisting of alkyl, O-alkyl, and a substituted or unsubstituted aromatic homocyclic or heterocyclic 5-ring or 6-ring having at least one OH group, preferably having an OH group in the beta position to carbonyl group; and

Vitamin C.

In a preferred embodiment of the invention, at least one R1, R2 or R3 in A12, A13 and/or A14 is a polyphenol having at least two OH groups and at least one R1, R2 or R3 is a substituted or unsubstituted phenyl group, preferably one Phenyl group with at least one alkyl group, preferably with at least two alkyl groups. In a further preferred embodiment of the invention, at least one R1, R2 or R3 in A12, A13 and/or A14 is a polyphenol having at least two OH groups and two R1, R2 or R3 are a substituted or unsubstituted phenyl group.

2,6-Di-tert-butylphenol (DTB), und

2,6-Di-tert-butyl-4-methyl-phenol (CH2-DTB), wobei * die Verknüpfung zu einer der Strukturen A1 bis A14 darstellt.According to a development of the invention, it is provided that the sterically hindered phenol has at least two steric alkyl groups, the sterically hindered phenol preferably being selected from the group consisting of

2,6-di-tert-butylphenol (DTB), and

2,6-di-tert-butyl-4-methyl-phenol (CH2-DTB), where * represents the linkage to one of structures A1 to A14.

2-(2,4-Dihydroxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine (EA52),

1,3,5-Tris(3,5-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazinane-2,4,6-trione (EA50),

Vitamin C (EA55).According to a development of the invention, it is provided that the at least one stabilizer additive is selected from the group consisting of:

2-(2,4-dihydroxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine (EA52),

1,3,5-Tris(3,5-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazinane-2,4,6-trione (EA50),

Vitamin C (EA55).

According to a development of the invention, it is provided that the at least one photoactive layer is an absorber layer, with the at least one photoactive layer preferably being formed as a mixed layer or of two adjacent layers with at least one donor and at least one acceptor, and the at least one donor and the at least one acceptor form a donor-acceptor system.

According to a development of the invention, it is provided that the at least one donor is an ADA oligomer and/or a BODIPY, and the at least one acceptor is an ADA oligomer and/or a fullerene.

According to one development of the invention, it is provided that the at least one stabilizer additive has an energy level at which the amount of the LUMO is less than the amount of the LUMO of the acceptor, preferably at least 0.1 eV less than the amount of the LUMO of the acceptor, preferably at least 0.2 eV less, or preferably at least 0.3 eV less, and the magnitude of the HOMO is greater than the magnitude of the HOMO of the donor, preferably at least 0.1 eV greater than the magnitude of the HOMO of the donor, preferably at least 0.2 eV greater , or preferably at least 0.3 eV larger.

A BODIPY compound is understood to mean in particular a compound of the general formula C9H7BN2F2, i.e. a compound with a boron difluoride group with a dipyrromethene group, in particular a compound 4,4-difluoro-4-bora-3a,4a-diaza- s-Indacene.

In particular, an ADA oligomer means a conjugated acceptor-donor-acceptor oligomer (A-D-A' oligomer) having an acceptor moiety (A) and another acceptor moiety (A'), each attached to a donor moiety (D) bound are understood.

According to a development of the invention, it is provided that the at least one stabilizer additive is contained exclusively in the at least one photoactive layer.

According to an alternative development of the invention, it is provided that the layer system has at least one transport layer, preferably at least two transport layers, which is arranged between the first electrode and the second electrode, the at least one transport layer being a hole conduction layer and/or an electron conduction layer, and where the at least one photoactive layer and at least one transport layer have at least one stabilizer additive.

In a preferred embodiment of the invention, the donor-acceptor system and/or the at least one stabilizer additive of at least one photoactive layer is processed in vacuo, ie applied to a layer of the layer system in vacuo.

In a preferred embodiment of the invention, the HOMO of the additive is at least 0.1 eV lower than the minimum of the HOMO of the donor relative to vacuum energy.

In a preferred embodiment of the invention, the LUMO of the additive is at least 0.1 eV higher than the minimum of the LUMO of the acceptor relative to vacuum energy.

The object of the present invention is also achieved by providing an organic electronic component with a layer system with at least one stabilizer additive according to the invention, in particular according to one of the exemplary embodiments described above, the at least one stabilizer additive preferably being present homogeneously in the photoactive layer and/or or the fullerene layer of the layer system. In this case, the advantages that have already been explained in connection with the layer system result in particular for the organic electronic component.

According to a development of the invention, it is provided that the organic electronic component is an organic photovoltaic element, an OFET, or an organic photodetector.

In a preferred embodiment of the invention, the layer system has further layers, such as charge carrier transport layers, also called transport layers, between the electrodes, which make little or no contribution to absorption compared to a photoactive layer.

In a preferred embodiment of the invention, at least one charge transport layer is arranged between the first electrode and the at least one photoactive layer and/or the second electrode and the at least one photoactive layer. In a preferred embodiment of the invention, the at least one photoactive layer is adjacent to at least one charge transport layer.

In a preferred embodiment of the invention, the layer system has at least two, preferably at least three, or preferably at least four photoactive layers. This is particularly advantageous since the incident light passes through a number of photoactive layers within the layer system. In a preferred embodiment of the invention, the layer system is designed as a tandem cell, triple cell or multiple cell.

The object of the present invention is also achieved by providing a use of a layer system according to the invention with at least one stabilizer additive in an organic electronic component, preferably an organic photovoltaic element, an OFET, or an organic photodetector, in particular according to one of those described above exemplary embodiments. The use of the layer system with at least one stabilizer additive in an organic electronic component results in particular in the advantages that have already been explained in connection with the layer system and the organic electronic component.

The invention is explained in more detail using the following exemplary embodiments and figures. The exemplary embodiments are intended to describe the invention without restricting it.

• 1 in einem Ausführungsbeispiel eine schematische Darstellung eines Schichtsystems eines organischen elektronischen Bauelements;
• 2 in einem Ausführungsbeispiel die Kurzschlussstromdichte, den Füllfaktor, die Leerlaufspannung und die Effizienz organischer elektronischer Bauelemente mit einem Schichtsystem mit einem Donor-Akzeptor-System aus Absorber1:C₆₀ ohne Stabilisator-Additiv, und jeweils mit den Stabilisator-Additiven EA59, EA 61 und EA62 in einer photoaktiven Schicht des Schichtsystems;
• 3 in einem Ausführungsbeispiel die Kurzschlussstromdichte, den Füllfaktor, die Leerlaufspannung und die Effizienz organischer elektronischer Bauelemente mit einem Schichtsystem mit einem Donor-Akzeptor-System aus Absorber1:C₆₀ ohne Stabilisator-Additiv, und mit dem Stabilisator-Additiv EA50 in einer photoaktiven Schicht des Schichtsystems;
• 4 in einem Ausführungsbeispiel die Kurzschlussstromdichte, den Füllfaktor, die Leerlaufspannung und die Effizienz organischer elektronischer Bauelemente mit einem Schichtsystem mit einem Donor-Akzeptor-System aus Absorber1:C₆₀ ohne Stabilisator-Additiv, und jeweils mit den Stabilisator-Additiv EA50 und EA52 in einer photoaktiven Schicht des Schichtsystems;
• 5 in einem Ausführungsbeispiel die Kurzschlussstromdichte, den Füllfaktor, die Leerlaufspannung und die Effizienz organischer elektronischer Bauelemente mit einem Schichtsystem mit einem Donor-Akzeptor-System aus Absorber2:C₆₀ ohne Stabilisator-Additiv, und mit dem Stabilisator-Additiv EA55 in einer photoaktiven Schicht eines Schichtsystems;
• 6 in einem Ausführungsbeispiel die Kurzschlussstromdichte, den Füllfaktor, die Leerlaufspannung und die Effizienz organischer elektronischer Bauelemente mit einem Schichtsystem mit einem Donor-Akzeptor-System aus Absorber1:C₆₀ ohne Stabilisator-Additiv,
• mit dem Stabilisator-Additiv EA55 in einer photoaktiven Schicht,
• und mit dem Stabilisator-Additiv EA55 in einer photoaktiven Schicht und einer Transportschicht des Schichtsystems;
• 7 in einem Ausführungsbeispiel die Kurzschlussstromdichte, den Füllfaktor, die Leerlaufspannung und die Effizienz organischer elektronischer Bauelemente mit einem Donor-Akzeptor-System mit einem Schichtsystem aus Absorber4:C₆₀ ohne Stabilisator-Additiv, und mit dem Stabilisator-Additiv EA55 in einer photoaktiven Schicht eines Schichtsystems;
• 8 in einem Ausführungsbeispiel die Kurzschlussstromdichte, den Füllfaktor, die Leerlaufspannung und die Effizienz organischer elektronischer Bauelemente mit einem Schichtsystem mit einem Donor-Akzeptor-System aus Absorber3:C₆₀ ohne Stabilisator-Additiv, mit dem Stabilisator-Additiv EA55 in einer photoaktiven Schicht, und mit dem Stabilisator-Additiv EA55 in einer Fulleren-Schicht eines Schichtsystems;
• 9 in einem Ausführungsbeispiel die Leitfähigkeit einer Transportschicht mit unterschiedlichen Anteil eines Stabilisator-Additivs.

In the following exemplary embodiments, it was shown in particular that at least one stabilizer additive according to the invention, at least in one photoactive layer and/or at least one fullerene layer of a layer system of an organic electronic component, surprisingly leads to the stability and/or the service life of the layer system is increased. It shows:

• 1 in one embodiment, a schematic representation of a layer system of an organic electronic component;
• 2 in one embodiment, the short-circuit current density, the fill factor, the open-circuit voltage and the efficiency of organic electronic components with a layer system with a donor-acceptor system from Absorber1: C ₆₀ without stabilizer additive, and each with the stabilizer additives EA59, EA 61 and EA62 in a photoactive layer of the layer system;
• 3 in one embodiment, the short-circuit current density, the fill factor, the open-circuit voltage and the efficiency of organic electronic components with a layer system with a donor-acceptor system from Absorber1: C ₆₀ without stabilizer additive, and with the stabilizer additive EA50 in a photoactive layer of the layer system ;
• 4 in one embodiment, the short-circuit current density, the fill factor, the open-circuit voltage and the efficiency of organic electronic components with a layer system with a donor-acceptor system from Absorber1: C ₆₀ without stabilizer additive, and each with the stabilizer additive EA50 and EA52 in a photoactive layer of the layer system;
• 5 in one embodiment, the short-circuit current density, the fill factor, the open-circuit voltage and the efficiency of organic electronic components with a layer system with a donor-acceptor system from Absorber2: C ₆₀ without stabilizer additive, and with the stabilizer additive EA55 in a photoactive layer of a layer system ;
• 6 in one embodiment, the short-circuit current density, the fill factor, the open-circuit voltage and the efficiency of organic electronic components with a layer system with a donor-acceptor system of absorber1:C ₆₀ without stabilizer additive,
• with the stabilizer additive EA55 in a photoactive layer,
• and with the stabilizer additive EA55 in a photoactive layer and a transport layer of the layer system;
• 7 in one embodiment, the short-circuit current density, the fill factor, the open-circuit voltage and the efficiency of organic electronic components with a donor-acceptor system with a layer system from Absorber4: C ₆₀ without stabilizer additive, and with the stabilizer additive EA55 in a photoactive layer of a layer system ;
• 8th in one embodiment, the short-circuit current density, the fill factor, the open-circuit voltage and the efficiency of organic electronic components with a layer system with a donor-acceptor system from Absorber3: C ₆₀ without stabilizer additive, with the stabilizer additive EA55 in a photoactive layer, and with the stabilizer additive EA55 in a fullerene layer of a layer system;
• 9 in one embodiment, the conductivity of a transport layer with different proportions of a stabilizer additive.

exemplary embodiments

1 1 shows, in one exemplary embodiment, a schematic representation of a layer system 1 of an electronic component.

mit mindestens einem R1, R2, und/oder R3 einem Polyphenol mit mindestens zwei OH-Gruppen, und/oder mindestens einem R1, R2, und/oder R3 einem sterisch gehinderten Phenol mit mindestens einer sterischen Alkylgruppe, wobei die sterische Alkylgruppe an der alpha-Position verzweigt ist, und mit R4 unabhängig voneinander ausgewählt aus der Gruppe bestehend aus H, OH, Alkyl, und Alkoxy;

mit mindestens einem R1, R2 und/oder R3 einem Polyphenol mit mindestens zwei OH-Gruppen, und/oder mindestens einem R1, R2 und/oder R3 einem sterisch gehinderten Phenol mit mindestens einer sterischen Alkylgruppe, wobei die sterische Alkylgruppe an der alpha-Position verzweigt ist, und mit R4 unabhängig voneinander ausgewählt aus der Gruppe bestehend aus H, OH, Alkyl, und Alkoxy;

mit mindestens einem R1, R2 und/oder R3 einem Polyphenol mit mindestens zwei OH-Gruppen, und/oder mindestens einem R1, R2 und/oder R3 einem sterisch gehinderten Phenol mit mindestens einer sterischen Alkylgruppe, wobei die sterische Alkylgruppe an der alpha-Position verzweigt ist;

mit mindestens einem R1, R2 und/oder R3 einem Polyphenol mit mindestens zwei OH-Gruppen;

mit R5 ausgewählt aus der Gruppe bestehend aus Alkyl, O-Alkyl, S-Alkyl, OH, und einem substituierten oder nicht-substituierten aromatischen homocyclischen oder heterocyclischen 5-Ring oder 6-Ring, wobei der 5-Ring oder 6-Ring bevorzugt weiter annelliert ist; und

Vitamin C (EA55), wobei der Anteil des mindestens einen Stabilisator-Additivs in der mindestens einen photoaktiven Schicht und/oder der mindestens einen Fulleren-Schicht 0,001 Gew.-% bis 30 Gew.-% beträgt, bevorzugt 0,001 Gew.-% bis 10 Gew.-%, oder bevorzugt 0,1 Gew.-% bis 2 Gew.-%.The layer system for an organic electronic component has a first electrode, a second electrode, and at least one photoactive layer and/or at least one fullerene layer, with the at least one photoactive layer and/or the at least one fullerene layer between the first electrode and the second electrode is arranged. The at least one photoactive layer and/or the at least one fullerene layer has at least one stabilizer additive, wherein the at least one stabilizer additive is selected from the group consisting of:

with at least one R1, R2, and/or R3 a polyphenol having at least two OH groups, and/or at least one R1, R2, and/or R3 a sterically hindered phenol having at least one steric alkyl group, the steric alkyl group being attached to the alpha -position is branched, and with R4 independently selected from the group consisting of H, OH, alkyl, and alkoxy;

with at least one R1, R2 and/or R3 a polyphenol having at least two OH groups, and/or at least one R1, R2 and/or R3 a sterically hindered phenol having at least one steric alkyl group, the steric alkyl group being in the alpha position is branched, and with R4 independently selected from the group consisting of H, OH, alkyl, and alkoxy;

with at least one R1, R2 and/or R3 a polyphenol having at least two OH groups, and/or at least one R1, R2 and/or R3 a sterically hindered phenol having at least one steric alkyl group, the steric alkyl group being in the alpha position is branched;

with at least one R1, R2 and/or R3 a polyphenol having at least two OH groups;

with R5 selected from the group consisting of alkyl, O-alkyl, S-alkyl, OH, and a substituted or unsubstituted aromatic homocyclic or heterocyclic 5-ring or 6-ring, with the 5-ring or 6-ring being preferred further is annulated; and

Vitamin C (EA55), where the proportion of the at least one stabilizer additive in the at least one photoactive layer and/or the at least one fullerene layer is 0.001% by weight to 30% by weight, preferably 0.001% by weight to 10% by weight, or preferably 0.1% to 2% by weight.

This increases the stability and/or the service life of a layer system with at least one photoactive layer and/or at least one fullerene layer with the at least one stabilizer additive. Improved stability and/or an increased service life of organic electronic components, in particular of organic solar cells, is advantageously obtained with such a layer system.

In one embodiment of the invention, at least one polyphenol of the groups R1, R2, R3 and/or R5 has at least one steric alkyl group and/or at least one sterically hindered phenol of the groups R1, R2 and/or R3 has at least two steric alkyl groups.

In a further embodiment of the invention, the stabilizer additive A15 to A18 R5 has an aromatic homocyclic or heterocyclic 5-membered ring or 6-membered ring with at least one OH group, preferably at least two OH groups, one OH group being in beta- Position to the carbonyl group of A15 to A18 R5 is arranged, preferably the stabilizer additive A15 to A18 R5 is a phenol, particularly preferably a polyphenol.

The layer system 1 for an organic electronic component has a substrate 2, a first electrode 3, a second electrode 7, at least one photoactive layer 5, and alternatively a supplementary fullerene layer 6, the at least one photoactive layer 5 and the at least one fullerene layer 6 is arranged between the first electrode 3 and the second electrode 7 . The at least one photoactive layer 5 has at least one stabilizer additive. In one configuration, the at least one stabilizer additive is at least largely homogeneously distributed in the at least one photoactive layer 5 . In a further embodiment of the invention, the fullerene layer 6 alternatively or additionally has at least one stabilizer additive. In one embodiment, the at least one stabilizer additive is distributed at least largely homogeneously in the at least one fullerene layer 6 .

In a further embodiment of the invention, at least two R1, R2 and/or R3 of the stabilizer additive A1 to A14 are polyphenols and/or at least two R1, R2 and/or R3 of the stabilizer additive A1 to A14 are sterically hindered phenols , preferably at least three.

In a further embodiment of the invention, at least one OH group of a polyphenol of the groups R1, R2, R3 and/or R5 is in the beta position or gamma position to a carbonyl group.

In a further embodiment of the invention, at least one polyphenol or a sterically hindered phenol from the groups R1, R2 and/or R3 of the stabilizer additive is bridged to another polyphenol or sterically hindered phenol by an alkyl group.

mit mindestens zwei R1, R2 und/oder R3 einem Polyphenol mit mindestens zwei OH-Gruppen, oder mindestens zwei sterisch gehinderten Phenolen mit mindestens einer sterischen Alkylgruppe, bevorzugt jeweils mit jeweils mindestens zwei sterischen Alkylgruppen, oder mindestens einem Polyphenol mit mindestens zwei OH-Gruppen und mindestens einem sterisch gehinderten Phenol mit mindestens einer, bevorzugt mindestens zwei sterischen Alkylgruppen, und mit R4 unabhängig voneinander ausgewählt aus H und einer Alkylgruppe;

mit mindestens zwei R1, R2 und/oder R3 einem Polyphenol mit mindestens zwei OH-Gruppen, oder mindestens zwei sterisch gehinderten Phenolen mit mindestens einer sterischen Alkylgruppe, bevorzugt jeweils mit mindestens zwei sterischen Alkylgruppen, oder mindestens einem Polyphenol mit mindestens zwei OH-Gruppen und mindestens einem sterisch gehinderten Phenol mit mindestens einer, bevorzugt mindestens zwei sterischen Alkylgruppen, und mit R4 unabhängig voneinander ausgewählt aus H und einer Alkylgruppe;

mit mindestens zwei R1, R2 und/oder R3 einem Polyphenol mit mindestens zwei OH-Gruppen, oder mindestens zwei sterisch gehinderten Phenolen mit mindestens einer sterischen Alkylgruppe, bevorzugt jeweils mit mindestens zwei sterischen Alkylgruppen, oder mit mindestens einem Polyphenol mit mindestens zwei OH-Gruppen und mindestens einem sterisch gehinderten Phenol mit mindestens einer, bevorzugt mindestens zwei sterischen Alkylgruppen;

mit mindestens einem R1, R2 und/oder R3 einem Polyphenol mit mindestens zwei OH-Gruppen und mindestens einem R1, R2 und/oder R3 einer substituierten oder nicht-substituierten Phenyl-Gruppe, bevorzugt mit mindestens einer Phenyl-Gruppe mit mindestens einer Alkylgruppe, bevorzugt mit mindestens zwei Alkylgruppen, wobei bevorzugt mindestens eine Alkylgruppe eine sterische Alkylgruppe ist, bevorzugt mit einem R1, R2 und/oder R3 einem Polyphenol mit mindestens zwei OH-Gruppen und zwei R1, R2 und/oder R3 einer substituierten oder nicht-substituierten Phenyl-Gruppe;

mit R5 ausgewählt aus der Gruppe bestehend aus Alkyl, O-Alkyl, und einem substituierten oder nicht-substituierten aromatischen homocyclischen oder heterocyclischen 5-Ring oder 6-Ring mit mindestens einer OH-Gruppe, bevorzugt mit einer OH-Gruppe in beta-Position zur Carbonyl-Gruppe; und

Vitamin C.In a further embodiment of the invention, the at least one stabilizer additive is selected from the group consisting of:

with at least two R1, R2 and/or R3 a polyphenol with at least two OH groups, or at least two sterically hindered phenols with at least one steric alkyl group, preferably each with at least two steric alkyl groups, or at least one polyphenol with at least two OH groups and at least one sterically hindered phenol having at least one, preferably at least two, steric alkyl groups, and with R4 independently selected from H and an alkyl group;

with at least two R1, R2 and/or R3 a polyphenol with at least two OH groups, or at least two sterically hindered phenols with at least one steric alkyl group, preferably each with at least two steric alkyl groups, or at least one polyphenol with at least two OH groups and at least one sterically hindered phenol having at least one, preferably at least two, steric alkyl groups, and with R4 independently selected from H and an alkyl group;

with at least two R1, R2 and/or R3 a polyphenol with at least two OH groups, or at least two sterically hindered phenols with at least one steric alkyl group, preferably each with at least two steric alkyl groups, or with at least one polyphenol with at least two OH groups and at least one sterically hindered phenol having at least one, preferably at least two, steric alkyl groups;

with at least one R1, R2 and/or R3 a polyphenol with at least two OH groups and at least one R1, R2 and/or R3 with a substituted or unsubstituted phenyl group, preferably with at least one phenyl group with at least one alkyl group, preferably with at least two alkyl groups, preferably with at least one alkyl group being a steric alkyl group, preferably with one R1, R2 and/or R3 a polyphenol with at least two OH groups and two R1, R2 and/or R3 a substituted or unsubstituted phenyl -Group;

with R5 selected from the group consisting of alkyl, O-alkyl, and a substituted or unsubstituted aromatic homocyclic or heterocyclic 5-ring or 6-ring having at least one OH group, preferably having an OH group in the beta position to carbonyl group; and

Vitamin C.

2,6-Di-tert-butylphenol (DTB), und

2,6-Di-tert-butyl-4-methyl-phenol (CH2-DTB), wobei * die Verknüpfung zu einer der Strukturen A1 bis A14 darstellt.In a further embodiment of the invention, the sterically hindered phenol has at least two steric alkyl groups, the sterically hindered phenol preferably being selected from the group consisting of

2,6-di-tert-butylphenol (DTB), and

2,6-di-tert-butyl-4-methyl-phenol (CH2-DTB), where * represents the linkage to one of structures A1 to A14.

2-(2,4-Dihydroxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine (EA52),

1,3,5-Tris(3,5-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazinane-2,4,6-trione (EA50),

Vitamin C (EA55).In a further embodiment of the invention, the at least one stabilizer additive is selected from the group consisting of:

2-(2,4-dihydroxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine (EA52),

1,3,5-Tris(3,5-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazinane-2,4,6-trione (EA50),

Vitamin C (EA55).

In a further embodiment of the invention, the at least one photoactive layer is an absorber layer, with the at least one photoactive layer preferably being formed as a mixed layer or of two adjacent layers with at least one donor and at least one acceptor, and the at least one donor and the at least one acceptor form a donor-acceptor system.

In a further embodiment of the invention, the at least one donor is an ADA oligomer and/or a BODIPY, and the at least one acceptor is an ADA oligomer and/or a fullerene.

In a further embodiment of the invention, the at least one stabilizer additive has an energy level at which the magnitude of the LUMO is smaller than the magnitude of the LUMO of the acceptor, preferably at least 0.3 eV smaller than the magnitude of the LUMO of the acceptor, and the magnitude of the HOMO is greater than the magnitude of the HOMO of the donor, preferably at least 0.3 eV greater than the magnitude of the HOMO of the donor.

In a further embodiment of the invention, the at least one stabilizer additive is contained exclusively in the at least one photoactive layer.

In an alternative embodiment of the invention, the layer system has at least one transport layer, preferably at least two transport layers, which is arranged between the first electrode and the second electrode, the at least one transport layer being a hole conduction layer and/or an electron conduction layer.

In a further configuration of the invention, the layer system has at least one transport layer, preferably at least two transport layers, which is arranged between the first electrode and the second electrode, the at least one transport layer being a hole conduction layer and/or an electron conduction layer, and the at least one photoactive layer and at least one transport layer have at least one stabilizer additive.

The organic electronic component with a layer system according to the invention has at least one stabilizer additive, the at least one stabilizer additive preferably being distributed homogeneously in the photoactive layer and/or the fullerene layer of the layer system.

In a further configuration of the invention, the organic electronic component is preferably an organic photovoltaic element, an OFET, or an organic photodetector.

In a further embodiment of the invention, the layer system according to the invention is used with at least one stabilizer additive in an organic electronic component, preferably an organic photovoltaic element, an OFET, or an organic photodetector.

Experiments on the evaporation of these stabilizer additives have shown that these compounds can be evaporated in a vacuum, and are at least largely stable. The stabilizer additives according to the invention can therefore be used in vacuum-processed organic photovoltaic elements.

The layer system 1 with at least one stabilizer additive is in particular for use in an organic electronic component, preferably in an organic photovoltaic element, an OFET, or an organic photodetector.

The organic electronic component with the layer system 1 according to the invention with at least one stabilizer additive, with the at least one stabilizer additive preferably being distributed homogeneously in the photoactive layer and/or the fullerene layer of the layer system, is in particular an organic photovoltaic element, in particular one organic solar cell, an OFET, or an organic photodetector.

In one exemplary embodiment, the electronic component with the layer system 1 is an organic solar cell. The layer system 1 is arranged on a transparent substrate 2, which is preferably designed to be flexible, in particular as a film. A first electrode 3 is arranged on the substrate 2 and is made, for example, of metal, a conductive oxide, in particular ITO, ZnO:Al or another transparent, conductive oxide or polymer, such as PEDOT:PSS or PANI. A charge carrier transport layer 4 is arranged on the first electrode 3 and is in the form of an electron or hole transport layer, for example. The photoactive layer 5, which comprises at least one donor and one acceptor material, which together form a donor-acceptor system, is arranged on the charge carrier transport layer 4. The photoactive layer 5 can also consist of more than one layer, in particular of a donor and acceptor layer, so that a planar, photoactive donor-acceptor transition is formed. In addition, the photoactive layer includes a stabilizer additive in a proportion of 0.1% by weight to 10% by weight. A further charge carrier transport layer 6 is arranged on the photoactive layer 5 . This charge carrier transport layer 6 is also designed as an electron or hole transport layer. The second electrode 7 is arranged on the charge carrier transport layer 6 and is formed, for example, from a metal such as Al, but can also consist of an optically transparent electrical conductor layer.

Vacuum co-evaporation with OPV materials selected from three functional classes was used to produce the layer system: co-evaporation with 1) absorber materials, 2) hole conductors, and 3) electron conductors (C ₆₀ ). Numerous cells were manufactured and characterized in vacuum systems for MIP and Lesker cells. An improvement in service life could be shown for the use of the stabilizer additives according to the invention in a photoactive layer and/or a fullerene layer.

Exemplary embodiments of layer systems 1 with stabilizer additives in photoactive layers 5 are shown below using MIP cells. Numerous cells were manufactured in MIP systems and Lesker and their efficiency and service life were characterized.

2 shows in one embodiment the short-circuit current density, the fill factor, the open-circuit voltage and the efficiency of organic electronic components with a layer system 1 with a donor-acceptor system from Absorber1: C ₆₀ without stabilizer additive (reference), and each with the stabilizer additives EA59 , EA 61 and EA62 in a photoactive layer (A) 5 of the layer system 1.

In this exemplary embodiment, the organic electronic component is a photovoltaic element. The short-circuit current density, the fill factor, the no-load voltage and the efficiency were each determined over a period of 100 h. Layer system 1 differs only in the addition of the stabilizer additive.

BPAPF: 9, 9-bis{4-[di(p-biphenyl)aminophenyl] }fluoreneThe layer system of a MIP cell with bulk heterojunction with a photoactive layer with absorber1 and a stabilizer additive mixed with absorber1 has the following structure for samples without stabilizer additive: material thickness / nm mixing ratio Substrate heating / °C Glass 10^6 - - - - ITO 150 - - - - C60 15 - - - - Absorber1:C60 25 1:1 (volume) 70 BPAPF 5 - - - BPAPF:NDP9 50 9:1 (weight) - - NDP9 1 - - - - Ouch 50 - - - - and samples with stabilizer additive: material thickness / nm mixing ratio Substrate heating / °C Glass 10^9 - - - - ITO 150 - - - - C60 15 - - - - Absorber1:C60:Additive 25 1:1:0.05 (volume) 70 BPAPF 5 - - - BPAPF:NDP9 50 9:1 (weight) - - NDP9 1 - - - - Ouch 50 - - - -
ITO: Indium Tin Oxide
NDP9: commercial p-dopant from Novaled GmbH
Absorber1:

BPAPF: 9,9-bis{4-[di(p-biphenyl)aminophenyl]}fluorenes

The organics and the gold layer are deposited in a high vacuum on a substrate pre-coated with ITO. The photoactive area defined by the overlap of ITO and gold is 6.4 mm ² . For aging, the samples are exposed in ambient air, without encapsulation, to radiation from a sun for 120 hours, simulated by xenon daylight lamps (1000W/m ² ). The samples reach a temperature of 75°C. The parameters of the cell were measured under AM1.5 lighting (AM = Air Mass; AM = 1.5 in this spectrum, the global radiant power is 1000 W/m ² ; AM = 1.5 as the standard value for measuring solar modules). The illuminant irradiates the sample in such a way that the gold layer is turned away from the light. The optoelectronic characterization of the samples is also carried out in air.

The efficiency of the photovoltaic element after aging for 120 h is summarized in Table 1 for the layer systems without stabilizer additive (reference) and with the stabilizer additives EA59, EA61 and EA62, each with absorber 1 in the photoactive layer. Table 1 Relative solar cell parameters after 120h aging / % sample short-circuit current open circuit voltage fill factor efficiency reference 0.50 0.99 0.85 0.42 EA62 0.79 1.02 0.76 0.62 EA61 0.87 1.04 0.86 0.77 EA5 9 0.94 1.03 0.76 0.74

3 shows in one embodiment the short-circuit current density, the fill factor, the open-circuit voltage and the efficiency of organic electronic components with a layer system 1 with a donor-acceptor system from Absorber1:C ₆₀ without stabilizer additive (reference), and with the stabilizer additive EA50 in a photoactive layer (A) of layer system 1.

Aging was determined over a period of 1000 hours. Layer system 1 differs only in the addition of the stabilizer additive EA50.

The layer system 1 of a MIP cell with volume heterojunction (bulk heterojunction) with a photoactive layer with absorber1 and a stabilizer additive mixed with absorber1 has the following structure for samples without stabilizer additive: material thickness / nm mixing ratio Substrate heating / °C Glass 10^6 - - - - ITO 150 - - - - C60:NDN45 5 4:1 (weight) - - C60 10 - - - - [Absorber] : C60 30 54 : 46 (volume) 85 [NHT49] 5 - - - - [NHT49] :NDP9 30 9:1 (weight) - - A1 100 - - - - and samples with stabilizer additive: material thickness / nm mixing ratio Substrate heating / °C Glass 10^6 - - - - ITO 150 - - - - C60:NDN45 5 4:1 (weight) - - C60 10 - - - - [Absorber] :C60:EA50 30 42:53:05 (volume) 85 [NHT49] 5 - - - - [NHT49] :NDP9 30 9:1 (weight) - - A1 100 - - - -
ITO: Indium Tin Oxide
NDP9: commercial p-dopant from Novaled GmbH
NHT49: commercial hole conductor from Novaled GmbH
Absorber1:

The organic and the aluminum layer are deposited in a high vacuum on a substrate pre-coated with ITO. The photoactive area defined by the overlap of ITO and aluminum is 6.4 mm ² . For aging, the samples are exposed, without encapsulation, to radiation from a sun for 1000 hours, simulated by xenon daylight lamps (1000W/m ² ). The samples reach a temperature of 75°C. The illuminant irradiates the sample in such a way that the gold layer is turned away from the light. The optoelectronic characterization of the samples is also carried out in air.

The efficiency of the photovoltaic element after aging for 1000 h is summarized in Table 2 for the layer systems without stabilizer additive (reference) and with the stabilizer additives EA50, each with absorber 1 in the photoactive layer. Table 2 Solar cell parameters after 1000h aging sample Short-circuit current density [mA/cm ² ] Open circuit voltage [V] fill factor [%] Efficiency [%] reference 8.9 0.83 52.7 3.9 EA50 in A 11.1 0.84 51.3 4.8

4 shows in one embodiment the short-circuit current density, the fill factor, the open-circuit voltage and the efficiency of organic electronic components with a layer system 1 with a donor-acceptor system of absorber 1:C ₆₀ without stabilizer additive (reference), and with the same donor-acceptor System Absorber1:C ₆₀ and added stabilizer additive EA050 in the photoactive layer (A), and with the same donor-acceptor system Absorber1:C ₆₀ and added stabilizer additive EA052 in the photoactive layer (A) of layer system 1.

These are standard mip cells with Au electrodes from a rapid test, which were first aged in air for 24 hours, followed by aging for 24 hours under 1000W halogen light with a spectrum and temperature that was not defined in more detail. The cells were measured before and after each aging step.

The layer system 1 of a MIP solar cell with volume heterojunction (bulk heterojunction) with a photoactive layer with absorber1 and a stabilizer additive mixed with absorber1 has the following structure for samples without stabilizer additive: material thickness / nm mixing ratio Substrate heating / °C Glass 10^6 - - - - ITO 150 - - - - C60 15 - - - - Absorber1:C60 25 1:1 (volume) 70 BPAPF 5 - - - - BPAPF:NDP9 50 9:1 (weight) - - NDP9 1 - - - - Ouch 50 - - - - and samples with stabilizer additive EA050 or EA052: material thickness / nm mixing ratio Substrate heating / °C Glass 10^6 - - - - ITO 150 - - - - C60 15 - - - - Absorber1:C60:Additive 25 1:1:0.05 (volume) 70 BPAPF 5 - - - - BPAPF:NDP9 50 9:1 (weight) - - NDP9 1 - - - - Ouch 50 - - - -

The organics and the gold layer are deposited in a high vacuum on a substrate pre-coated with ITO. The photoactive area defined by the overlap of ITO and gold is 6.4 mm ² . For aging, the samples are initially stored in ambient air, without encapsulation, for 24 h and then exposed to radiation from the sun for a further 24 hours, simulated by halogen lamps (1000 W/m ² ). The parameters of the cell were measured under AM1.5 lighting (AM = Air Mass; AM = 1.5 in this spectrum, the global radiant power is 1000 W/m ² ; AM = 1.5 as the standard value for measuring solar modules). The illuminant irradiates the sample in such a way that the gold layer is turned away from the light. The optoelectronic characterization of the samples is also carried out in air.

5 shows in one embodiment the short-circuit current density, the fill factor, the open-circuit voltage and the efficiency of organic electronic components with a layer system 1 with a donor-acceptor system of Absorber2:C ₆₀ without stabilizer additive (reference), and with the stabilizer additive EA55 in a photoactive layer (A) 5 of a layer system 1.

In this exemplary embodiment, the organic electronic component is a photovoltaic element. The short-circuit current density, the fill factor, the no-load voltage and the efficiency were each determined over a period of 1000 h. Layer system 1 differs only in the addition of the stabilizer additive.

The layer system of a solar cell with volume heterojunction (bulk heterojunction) with a photoactive layer with absorber2 and a stabilizer additive added to absorber2 has the following structure for samples without stabilizer additive: material thickness / nm mixing ratio Substrate heating / °C Glass 10^6 - - - - ITO 150 - - - - C60:NDN45 5 4 : 1 (weight) - - C60 10 - - - - [Absorber2] :C60 30 7 : 3 (volume) 45 [NHT49] 5 - - - - [NHT49] :NDP9 30 9:1 (weight) - - MoO3 15 A1 100 - - - -
and samples with stabilizer additive: material thickness / nm mixing ratio Substrate heating / °C Glass 10^6 - - - - ITO 150 - - - - C60:NDN45 5 4 : 1 (weight) - - C60 10 - - - - [Absorber2] :C60:EA55 30 67:28:5 (volume) 45 [NHT49] 5 - - - - [NHT49] :NDP9 30 9:1 (weight) - - MoO3 15 A1 100 - - - -
NDP9: commercial p-dopant from Novaled GmbH
NDN45: commercial n-dopant from Novaled GmbH
NHT49: commercial hole conductor from Novaled GmbH
Absorber2:

The organic and the aluminum layer are deposited in a high vacuum on a substrate pre-coated with ITO. The photoactive area defined by the overlap of ITO and aluminum is 6.4 mm ² . For aging, the samples are exposed, without encapsulation, to radiation from a sun for 1120 hours, simulated by xenon daylight lamps (1000W/m ² ). The samples reach a temperature of 75°C. The illuminant irradiates the sample in such a way that the gold layer is turned away from the light. The optoelectronic characterization of the samples is also carried out in air.

The efficiency of the photovoltaic element after aging for 1120 h is summarized in Table 3 for the layer systems without stabilizer additive (reference) and with the stabilizer additive EA55, each with absorber 2 in the photoactive layer. Table 3 Relative solar cell parameters after 1120h aging / % sample Short-circuit current density [mA/cm ² ] Open circuit voltage [V] fill factor [%] Efficiency [%] reference 10.1 0.87 56.0 4.9 EA55 11.3 0.87 57.5 5.6

It turns out that the absorber2 degrades very quickly in air. With the stabilizer additive EA055 as an admixture in the absorber layer for Absorber2, the degradation was minimized compared to such a MIP cell without stabilizer additive.

Surprisingly, EA55 (ascorbic acid, vitamin C) is particularly suitable as a stabilizer additive for increasing the service life of an organic photovoltaic element. Surprisingly, ascorbic acid also leads to improved initial efficiency. Although a loss of initial efficiency was observed in a few cases, this is overcompensated over time by a reduced loss of efficiency over the course of the period of use of the photovoltaic element.

6 shows in one embodiment the short-circuit current density, the fill factor, the open circuit voltage and the efficiency of organic electronic components with a layer system 1 with a donor-acceptor system from Absorber1: C ₆₀ without stabilizer additive (reference), with the stabilizer additive EA55 in one photoactive layer (A) 5, and with the stabilizer additive EA55 in a photoactive layer (A) and a transport layer (T) 4 of the layer system 1.

In this exemplary embodiment, the organic electronic component is a photovoltaic element. The short-circuit current density, the fill factor, the no-load voltage and the efficiency were each determined over a period of 1000 h. Layer system 1 differs only in the addition of the stabilizer additive. Absorber1 was used as the absorber. EA55 (L-Ascorbic Acid, Vitamin C) was used as a stabilizer additive in various layers of layer system 1.

The layer system 1 of a solar cell with volume heterojunction (bulk heterojunction) with a photoactive layer 5 with the absorber 1 and a stabilizer additive mixed into the absorber 1 or a stabilizer additive mixed into a fullerene layer (C ₆₀ ) 6 has the following structure for samples without stabilizer additive: material thickness / nm mixing ratio Substrate heating / °C Glass 10^6 - - - - ITO 150 - - - - C60:NDN45 5 4 : 1 (weight) - - C60 10 - - - - [Absorber] : C60 30 54 : 46 (volume) 85 [NHT49] 5 - - - - [NHT49] :NDP9 30 9:1 (weight) - - MoO3 15 A1 100 - - - - with stabilizer additive in the photoactive layer: material thickness / nm mixing ratio Substrate heating / °C Glass 10^6 - - - - ITO 150 - - - - C60:NDN45 5 4 : 1 (weight) - - C60 10 - - - - [Absorber] : C60: EA55 30 42:53:5 (volume) 85 [NHT49] 5 - - - - [NHT49] :NDP9 30 9:1 (weight) - - MoO3 15 A1 100 - - - - with stabilizer additive in the photoactive layer and the fullerene layer: material thickness / nm mixing ratio Substrate heating / °C Glass 10^6 - - - - ITO 150 - - - - C60:NDN45:EA55 5 75:20:5 (weight) - - C60:EA55 10 95:5 (weight) - - [Absorber] : C60: EA55 30 42:53:5 (volume) 85 [NHT49] 5 - - - - [NHT49] :NDP9 30 9:1 (weight) - - MoO3 15 A1 100 - - - -
NDP9: commercial p-dopant from Novaled GmbH
NDN45: commercial n-dopant from Novaled GmbH
NHT49: commercial hole conductor from Novaled GmbH
Absorber1:

The efficiency of the photovoltaic element after aging for 1160 h is summarized in Table 4 for the layer systems without stabilizer additive (reference) and with the stabilizer additive EA55, each with absorber 1 in the photoactive layer. The stabilizer additive EA55 is either only in the photoactive layer (A) or both in the photoactive layer (A) and in the electron transport layer (T). Table 4 Relative solar cell parameters after 1160h aging / % sample Short-circuit current density [mA/cm ² ] Open circuit voltage [V] fill factor [%] Efficiency [%] reference 8.5 0.86 50 3.6 EA55:A 9.6 0.85 51.7 4.2 EA55: A, T 10.4 0.86 59.0 5.3

The admixture of the stabilizer additive EA055 in the absorber layer or in the electron conduction layer (ETL layer) C ₆₀ leads to a significant improvement in the efficiency of the photovoltaic element after aging.

7 shows in one embodiment the short-circuit current density, the fill factor, the open-circuit voltage and the efficiency of organic electronic components with a donor-acceptor system with a layer system 1 of Absorber4:C ₆₀ without stabilizer additive (reference), and with the stabilizer additive EA55 in a photoactive layer (A) 5 of a layer system 1 (A).

In this exemplary embodiment, the organic electronic component is a photovoltaic element. The short-circuit current density, the fill factor, the no-load voltage and the efficiency were each determined over a period of 1000 h. Layer system 1 differs only in the addition of the stabilizer additive.

The structure of the layer system 1 corresponds to the structure according to FIG 6 , whereby absorber 4 was used instead of absorber 1.

Absorber4:

The addition of the stabilizer additive EA055 to the absorber layer (A) leads to a significant improvement in the efficiency of the photovoltaic element after aging.

8th shows in one embodiment the short-circuit current density, the fill factor, the open-circuit voltage and the efficiency of organic electronic components with a layer system 1 with a donor-acceptor system from Absorber3: C ₆₀ without stabilizer additive (reference), with the stabilizer additive EA55 in one photoactive layer (A), and with the stabilizer additive EA55 in a fullerene layer (T) of a layer system 1.

In this exemplary embodiment, the organic electronic component is a photovoltaic element. The short-circuit current density, the fill factor, the no-load voltage and the efficiency were each determined over a period of 200 h. Layer system 1 differs only in the addition of the stabilizer additive.

The structure of the layer system 1 corresponds to the structure according to FIG 6 , whereby absorber 3 was used instead of absorber 1.

Absorber3:

The admixture of the stabilizer additive EA055 in the absorber layer (A) or in the fullerene layer C ₆₀ (ETL layer) (T) leads to a significant improvement in the efficiency of the photovoltaic element after aging.

9 shows in one embodiment the conductivity of a transport layer with different proportions of a stabilizer additive.

The conductivity of C ₆₀ layers with 5%, 10% or 20% of the commercial n-dopant NDN45 from Novaled GmbH was increased with and without the stabilizer additive EA55 (L-Ascorbic Acid, Vitamin C) in a proportion of 5 wt% measured. An n-doping with 5% by weight, 10% by weight and 20% by weight with NDN45 and with an additional stabilizer additive EA055 of less than 5% by weight showed no significant difference to corresponding layers without the stabilizer -Additive EA055.

The conductivity increases linearly depending on the proportion of n-doping with the dopant NDN45. This shows that adding the stabilizer additive to stabilize an n-layer does not negatively affect the conductivity of this layer.

Doping tests have shown that the co-evaporation of a stabilizer additive (L-ascorbic acid, EA055) as an admixture to an electron transport layer n-ETL (here: C ₆₀ :NDN45) does not negatively affect the doping effect of an ETL layer (electron conducting layer). .

QUOTES INCLUDED IN DESCRIPTION

This list of the documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• US20150228925A1 [0010]

Claims (10)

Layer system for an organic electronic component, with a first electrode, a second electrode, and at least one photoactive layer and/or at least one fullerene layer, the at least one photoactive layer and/or the at least one fullerene layer between the first electrode and of the second electrode, characterized in that the at least one photoactive layer and/or the at least one fullerene layer has at least one stabilizer additive, the at least one stabilizer additive being selected from the group consisting of:

with at least one R1, R2, and/or R3 a polyphenol having at least two OH groups, and/or at least one R1, R2, and/or R3 a sterically hindered phenol having at least one steric alkyl group, the steric alkyl group being attached to the alpha -position is branched, and with R4 independently selected from the group consisting of H, OH, alkyl, and alkoxy;

with at least one R1, R2 and/or R3 a polyphenol having at least two OH groups, and/or at least one R1, R2 and/or R3 a sterically hindered phenol having at least one steric alkyl group, the steric alkyl group being in the alpha position is branched, and with R4 independently selected from the group consisting of H, OH, alkyl, and alkoxy;

with at least one R1, R2 and/or R3 a polyphenol having at least two OH groups, and/or at least one R1, R2 and/or R3 a sterically hindered phenol having at least one steric alkyl group, the steric alkyl group being in the alpha position is branched;

with at least one R1, R2 and/or R3 a polyphenol having at least two OH groups;

with R5 selected from the group consisting of alkyl, O-alkyl, S-alkyl, OH, and a substituted or unsubstituted aromatic homocyclic or heterocyclic 5-ring or 6-ring, with the 5-ring or 6-ring being preferred further is annulated; and

Vitamin C (EA55), where the proportion of the at least one stabilizer additive in the at least one photoactive layer and/or the at least one fullerene layer is 0.001% by weight to 30% by weight, preferably 0.001% by weight to 10% by weight, or preferably 0.1% to 2% by weight. shift system claim 1 , characterized in that at least one polyphenol of the groups R1, R2, R3 and/or R5 has at least one steric alkyl group, and/or at least one sterically hindered phenol of the groups R1, R2 and/or R3 has at least two steric alkyl groups, and/ or the stabilizer additive A15 to A18 R5 has an aromatic homocyclic or heterocyclic 5-ring or 6-ring with at least one OH group, preferably at least two OH groups, one OH group being in the beta position to the carbonyl group of A15 to A18 R5 is arranged, preferably the stabilizer additive A15 to A18 R5 has a phenol, particularly preferably a polyphenol. shift system claim 1 or 2 , characterized in that at least two R1, R2, and/or R3 of the stabilizer additive A1 to A14 are polyphenols, and/or at least two R1, R2, and/or R3 of the stabilizer additive A1 to A14 are sterically hindered phenols, preferably at least three and/or at least one OH group of a polyphenol of the groups R1, R2, R3 and/or R5 is in the beta position or gamma position to a carbonyl group, and/or at least one polyphenol or a sterically hindered one Phenol of the groups R1, R2 and/or R3 of the stabilizer additive is bridged with another polyphenol or sterically hindered phenol by an alkyl group. Layer system according to one of the preceding claims, characterized in that the at least one stabilizer additive is selected from the group consisting of:

with at least two R1, R2 and/or R3 a polyphenol with at least two OH groups, or at least two sterically hindered phenols each with at least one steric alkyl group, preferably each with at least two steric alkyl groups, or at least one polyphenol with at least two OH groups and at least one sterically hindered phenol having at least one, preferably at least two, steric alkyl groups, and with R4 independently selected from H and an alkyl group;

with at least two R1, R2 and/or R3 a polyphenol with at least two OH groups, or at least two sterically hindered phenols with at least one steric alkyl group, preferably each with at least two steric alkyl groups, or at least one polyphenol with at least two OH groups and at least one sterically hindered phenol having at least one, preferably at least two, steric alkyl groups, and with R4 independently selected from H and an alkyl group;

with at least two R1, R2 and/or R3 a polyphenol with at least two OH groups, or at least two sterically hindered phenols with at least one steric alkyl group, preferably each with at least two steric alkyl groups, or with at least one polyphenol with at least two OH groups and at least one sterically hindered phenol having at least one, preferably at least two, steric alkyl groups;

with at least one R1, R2 and/or R3 a polyphenol with at least two OH groups and at least one R1, R2 and/or R3 with a substituted or unsubstituted phenyl group, preferably with at least one phenyl group with at least one alkyl group, preferably with at least two alkyl groups, preferably with at least one alkyl group being a steric alkyl group, preferably with one R1, R2 and/or R3 a polyphenol with at least two OH groups and two R1, R2 and/or R3 a substituted or unsubstituted phenyl -Group;

with R5 selected from the group consisting of alkyl, O-alkyl, and a substituted or unsubstituted aromatic homocyclic or heterocyclic 5-ring or 6-ring having at least one OH group, preferably having an OH group in the beta position to carbonyl group; and

Vitamin C. Layer system according to one of the preceding claims, characterized in that the sterically hindered phenol has at least two steric alkyl groups, the sterically hindered phenol preferably being selected from the group consisting of

2,6-di-tert-butylphenol (DTB), and

2,6-di-tert-butyl-4-methyl-phenol (CH2-DTB), where * represents the linkage to one of structures A1 to A14. Layer system according to one of the preceding claims, characterized in that the at least one stabilizer additive is selected from the group consisting of:

2-(2,4-dihydroxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine (EA52),

1,3,5-Tris(3,5-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazinane-2,4,6-trione (EA50),

Vitamin C (EA55). Layer system according to one of the preceding claims, characterized in that the at least one photoactive layer is an absorber layer, wherein the at least one photoactive layer is preferably formed as a mixed layer or from two adjacent layers with at least one donor and at least one acceptor, and the at least one donor and the at least one acceptor form a donor-acceptor system, wherein preferably the at least one donor is an ADA oligomer and/or a BODIPY, and wherein the at least one acceptor is an ADA oligomer and/or a fullerene, and/or the at least one stabilizer additive has an energy level at which the absolute value of the LUMO is less than the absolute value of the LUMO of the acceptor, preferably at least 0.3 eV less than the absolute value of the LUMO of the acceptor, and the absolute value of the HOMO is greater than the absolute value of the HOMO The donor is preferably at least 0.3 eV greater than the magnitude of the HOMO of the donor. Layer system according to one of the preceding claims, characterized in that the at least one stabilizer additive is contained exclusively in the at least one photoactive layer, or the layer system has at least one transport layer, preferably at least two transport layers, which are arranged between the first electrode and the second electrode is, wherein the at least one transport layer is a hole conducting layer and/or an electron conducting layer, and wherein the at least one photoactive layer and at least one transport layer have at least one stabilizer additive. Organic electronic component with a layer system with at least one stabilizer additive according to one of Claims 1 until 8th , wherein the at least one stabilizer additive is preferably distributed homogeneously in the photoactive layer and/or the fullerene layer of the layer system, and wherein the organic electronic component is preferably an organic photovoltaic element, an OFET, or an organic photodetector. Use of a layer system with at least one stabilizer additive according to one of Claims 1 until 8th in an organic electronic component, preferably an organic photovoltaic element, an OFET, or an organic photodetector.

Images