Organic electronic component comprising a conversion contact located between two photoactive layers

Abstract

The invention relates to an organic electronic component (50) comprising a layer system (20) between a first electrode (2) and a second electrode (9), and comprising, in the layer system (20), at least a first photoactive layer (4) and a second photoactive layer (7), and a conversion contact (30) located between the first photoactive layer (4) and the second photoactive layer (7).

Description

[0001] Organic electronic component with a conversion contact arranged between two photoactive layers

[0002] The invention relates to an organic electronic component with a layer system comprising a first photoactive layer and a second photoactive layer, and a conversion contact arranged between the first photoactive layer and the second photoactive layer.

[0003] Electronic components with photoactive layers, in particular LEDs or solar cells, are now widely used in everyday and industrial environments. Well-known solar cells preferably have active layers made of amorphous silicon (a-Si) or GIGS (Cu (In, Ga) (S, Se) 2 ). Solar cells with organic photoactive layers are also known. The organic photoactive layers can be made of polymers or small molecules. While polymers are not vaporizable and can therefore only be applied from solutions, small molecules are vaporizable. Solar cells convert electromagnetic radiation into electrical energy. In contrast to solar cells based on silicon, in organic solar cells free charge carriers are not directly generated by electromagnetic radiation. Instead excitons, i.e. electrically neutral excited states (bound electron-hole pairs), are formed first.Only in a second step are these excitons separated into free charge carriers, which then contribute to the flow of electrical current.

[0004] Organic electronic components, especially organic photovoltaic elements, typically consist of a series of thin layers between two electrodes, which are preferably vacuum-deposited or solution-processed. Electrical contact can be achieved by metal layers, transparent conductive oxides (TCOs), and / or transparent conductive polymers (PEDOT-PSS, PANI).

[0005] Many organic photovoltaic elements have two or more stacked subcells or photoactive layers connected in series. Between the subcells, connecting units, so-called pn junctions, are arranged to transport charge between photoactive layers. The connecting unit enables recombination of photogenerated electrons from one subcell with photogenerated holes from the adjacent subcell. The connecting units can be formed from multiple layers with different electronic properties.

[0006] The energy losses during this recombination should be as low as possible, i.e., the voltage drop across the layer sequence under a current flow Isc, which occurs during illumination, should be as small as possible compared to the open-circuit voltage Voc of the photovoltaic element under the same illumination. This low voltage drop ("low contact resistance") should be maintained even under long thermal stress. Furthermore, the layer system should be as robust as possible against the influence of moisture, oxygen, and possible evaporation from adhesives used in encapsulation of the photovoltaic element.

[0007] The efficiency of organic solar cells has been significantly increased in recent years by means of donor / acceptor interfaces, bulk heterojunctions, tandem structures, and new materials, particularly new absorbers. However, an improvement in the lifetime of organic solar cells is desirable. The efficiency (power conversion efficiency, PCE) of organic solar cells decreases over time as a result of degradation processes caused by the exposure of the organic electronic materials to light, heat, oxygen, and / or water, or evaporation from adjacent layers, such as films or adhesive layers.

[0008] The requirement for a connection unit between two adjacent subcells of photovoltaic elements that is stable even under continuous load proves to be a major challenge in practice, especially with photovoltaic elements encapsulated on polymer films. Films and adhesives are not completely free of moisture and solvents, and adhesives generally release fumes that damage the layer system. This applies to epoxy- or acrylic-resin-based one- or two-component bonds with thermal and / or light-induced curing, as well as to silicone-based pressure-sensitive adhesives (PSAs).Accordingly, for a photovoltaic element with multiple subcells, a faster increase in the contact resistance of the layer system is observed in accelerated aging tests when the photovoltaic element is deposited on films, protected with films, or encapsulated, compared to glass or metal encapsulation. The increase in contact resistance is evident from the current-voltage characteristics as a reduced slope of the current-voltage curve in the vicinity of Voc and, consequently, a reduced fill factor and correspondingly reduced efficiency. This often applies not only to aging in a humid atmosphere (damp heat test) under the influence of penetrating moisture, but also to aging in a dry atmosphere (dry heat test), where damaging influences originate primarily from the film composite and the adhesive bonds. Connection regions between two photoactive layers are known from the prior art:

[0009] US2006 / 0263629A1 discloses OLEDs with two electroluminescent units separated by a connecting element, with an electron injection layer, a metal-organic layer, and a hole injection layer.

[0010] W02007 / 071450A1 discloses an electronic component with a pn- junction, wherein the n-type layer has a dopant with a redox potential of < 1.5 eV and the p-type layer has a dopant with a redox potential of > 0 eV.

[0011] US 6717358B1 discloses OLEDs designed as tandem cells with two electroluminescent units and a connection region which is composed of a doped n-type layer, an intermediate layer and a doped p-type layer, wherein the intermediate layer has a band gap of less than 4.0 eV.

[0012] EP 1 351 558 B1 discloses organic electroluminescent devices with a charge-generating layer between two light-emitting layers, which have an increased lifetime with higher luminosity.

[0013] US7494722B2 discloses tandem OLEDs, wherein a connecting region consists of an n-doped organic layer and an electron-accepting layer with an organic material having a reduction potential greater than -0.5 eV (vs. SCE). An intermediate layer made of a metal or a metallic compound can be arranged between the n-doped organic layer and the electron-accepting layer to limit the diffusion of the materials between the two layers.

[0014] US 2008 / 0030131A1 discloses a light-emitting component having a first light-emitting unit and a second light-emitting unit and an organic compound unit arranged therebetween.

[0015] Forrest et al. (Appl. Phys. Lett., 2020, 80, 1667) disclose tandem solar cells with a layer system comprising a phthalocyanine, a perylenedicarboxylic acid derivative, and a layer of silver clusters. However, the silver clusters exhibit parasitic absorption, which reduces the efficiency of the solar cell.

[0016] As organic solar cells age, a decrease in efficiency can be observed, particularly at higher temperatures. This is largely due to a loss of fill factor. The connecting unit between two photoactive layers plays a key role and influences the lifetime of organic solar cells. At the interface between the p- and n-doped layers of the pn-junction, strong p-dopants and n-dopants collide, which often leads to undesirable chemical interactions. In particular, the dopants can come into contact with each other at the interface and react, thus canceling out their doping effect.Such interactions can be accelerated in an encapsulated organic solar cell under the influence of evaporation from the encapsulation film and / or the adhesive, especially with different classes of dopants that tend to react, and in the presence of solvent-like species released by adhesives that can promote the diffusion of dopants.

[0017] A disadvantage of the prior art, however, is that the aging of organic electronic components with a conventional connection unit (pn- junction) between photoactive layers leads to a decrease in efficiency, in particular in the fill factor. This is particularly true for organic electronic components encapsulated with films and adhesive layers, since adhesives used in encapsulation can diffuse and damage the layer system, which leads to lower efficiency of the electronic components over time and thus to a shortening of the component's lifetime. There is a need to increase the lifetime of organic electronic components, in particular of light-absorbing electronic components.

[0018] The invention is therefore based on the object of providing an organic electronic component with at least a first photoactive layer and a second photoactive layer and a conversion contact arranged therebetween, wherein the aforementioned disadvantages do not occur, and wherein in particular an improved service life of such an organic electronic component, in particular an organic photovoltaic element, is provided with such a layer system.

[0019] The problem is solved by the subject matter of the independent claims. Advantageous embodiments emerge from the subclaims.

[0020] The object is achieved in particular by providing an organic electronic component with a first electrode, a second electrode, and a layer system arranged between the first electrode and the second electrode, comprising a first photoactive layer and a second photoactive layer, wherein a conversion contact is arranged between the first photoactive layer and the second photoactive layer. The conversion contact comprises layers arranged in the following order: a) a doped or undoped p-type layer with an optical band gap of greater than 2.5 eV, wherein the p-type layer has an ionization energy of greater than 5.0 eV; b) an n-doped intermediate layer with a matrix material and at least one n-dopant, wherein the n-doped intermediate layer has an electron affinity of greater than 4.4 eV, and wherein the proportion of the at least one n-dopant is 1 to 30 vol.-%; and c) a doped n-type layer with an electron transport material (ETM) and at least one n-dopant, wherein the n-type layer has an electron affinity of less than 4.4 eV. According to the invention, a conversion contact is therefore provided in particular, wherein an additional n-doped intermediate layer is arranged between the p-type layer and the n-type layer of a pn junction. The energy levels of the individual layers of the conversion contact and the relationship of the energy levels of the individual layers of the conversion contact to one another are decisive for the stability of the two adjacent photoactive layers.

[0021] A conversion contact is understood in particular to be a layer sequence between two photoactive layers which connects the photoactive layers in series, the photoactive layers being in particular light-absorbing layers.

[0022] In a preferred embodiment, the matrix material of the n-doped intermediate layer is an electron transport material (ETM).

[0023] A photoactive layer can be constructed from one or more layers, in particular as a bulk heterojunction (BHJ) or as a planar heterojunction (PHJ).

[0024] In a preferred embodiment, the organic electronic component has a non-inverted layer system, a so-called pin structure. In an alternative preferred embodiment, the organic electronic component has an inverted layer system, a so-called nip structure. An inverted layer system is understood in particular to mean that the electrodes and the individual layers of the layer system, thus also the photoactive layers, are applied to a substrate in the reverse order compared to the non-inverted layer system.

[0025] In a preferred embodiment, a transport layer is arranged between the first electrode and the first photoactive layer and between the second electrode and the second or a further photoactive layer, wherein each of the transport layers is independently a hole transport layer or an electron transport layer, preferably an electron transport layer (ETL) is arranged between the first electrode and the first photoactive layer, and a hole transport layer (HTL) is arranged between the second or a further photoactive layer and the second electrode.

[0026] The term "photoactive" refers, in particular, to the conversion of light energy into electrical energy. Absorber materials in photoactive layers exhibit 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 polarization state upon exposure to light.

[0027] A photoactive layer is understood, in particular, to be a layer of an electronic component that contributes to the absorption of radiation (for the generation of electrical energy). In a preferred embodiment, the photoactive layer is a light-absorbing layer, in particular a light-absorbing layer of a photovoltaic element.

[0028] A p-type layer is understood to be, in particular, a layer made of a matrix material or a layer made of a matrix material (for transporting holes) and a p-dopant (for providing holes). The p-type layer is, in particular, a hole transport layer (HTL) and promotes the transport of positive charge carriers (holes) from a photoactive layer to an electrode and / or between two photoactive layers. The p-type layer, in particular, has a hole transport material (HTM) as the matrix material.

[0029] In a preferred embodiment, the p-type layer of the conversion contact comprises an organic hole transport material (HTM) as matrix material, alone or in combination with a p-dopant. Preferably, the matrix material of the p-type layer is a tetraaryldiamine derivative having at least two amino groups and at least two aryl units therebetween, in particular a compound of the formula II where Ari, Ar2, Ars and Ari are each independently a substituted or unsubstituted aryl group, Ar is independently a substituted or unsubstituted aryl group, and n is at least 2, preferably n = 2, 3, 4 or 5. Preferably, the substituent of Ar1, Ar2, Ar3 and Ar4 is selected from the group consisting of halogen, amino group, preferably an amino group substituted with two aryl groups, alkyl group, alkenyl group, alkoxy group, and aryl group.

[0030] In a preferred embodiment, the p-type layer is doped, preferably with a p-dopant in a proportion of 1 to 20 wt.%, preferably 2 to 20 wt.%.

[0031] In a preferred embodiment, the doped or undoped p-type layer has an optical band gap of greater than 2.8 eV, preferably greater than 3.0 eV, or preferably greater than 3.3 eV.

[0032] An n-type layer is understood, in particular, to be a layer composed of two materials: a matrix material (for transporting electrons) and a dopant (for providing electrons). The n-type layer is, in particular, an electron transport layer (ETL). The n-type layer, in particular, comprises an organic n-type material as the matrix material, preferably an electron transport material (ETM), and an n-dopant.

[0033] The HOMO and LUMO energy levels can be determined from the redox potentials of the molecules, for which measurement methods are sufficiently described in the literature. Alternatively, HOMO and LUMO

[0034] Energies or the corresponding ionization energies and

[0035] Electron affinities can be determined from photoelectron spectroscopy and inverse photoelectron spectroscopy.

[0036] The LUMO and HOMO energy levels were calculated alternatively based on the B3LYP method of the program Gaussian 98 (Gaussian, Inc., Pittsburgh, PA). The basis set of the B3LYP method was defined as MIDI! for all available atoms and 6-31G* for all remaining atoms. The relative HOMO values ​​calculated in this way were related to the material N,N ' -diphenyl-N,N-bis ( 3 -methylphenyl ) -1 , 1 ' -biphenyl -4 , 4 ' -diamine (TPD) , which was investigated in the literature and for which an ionization energy of 5.3 eV was determined (C. Adachi et al., Appl . Phys. Lett. 66, 2679-2681 (1995) ). This results in the energy levels mentioned in the embodiments. Fullerene C60 has an electron affinity of 4.0 eV (W. Zhao, A. Kahn, Charge transfer at n-doped organic- organic heterojunctions, J. Appl. Phys. , 105 (12) (2009) 123711) .

[0037] An optical band gap is understood in particular as the photon energy value at which the absorption spectrum of a material has a first inflection point.

[0038] In a preferred embodiment, the p-type layer has an ionization energy of greater than 4.8 eV, preferably greater than 4.9 eV, preferably greater than 5.0 eV, preferably greater than 5.2 eV, preferably greater than 5.4 eV, or preferably greater than 5.5 eV, and preferably the p-type layer has an ionization energy of less than 7.0 eV, preferably less than 6.8 eV, or preferably less than 6.6 eV.

[0039] According to a further development of the invention, it is provided that the p-type layer has an ionization energy of greater than 5.2 eV, preferably greater than 5.4 eV, preferably from 5.2 eV to 6.0 eV, or preferably from 5.2 to 5.6 eV.

[0040] Suitable matrix materials of the p-type layer are in particular selected from the group consisting of N4, N4, N4', N4' -tetra[(1,1'-biphenyl)-4-yl]-(l,l'-biphenyl)-4,4'-diamine (BPBPA), N4,N4,N4' ',N4' '-tetra([1,1'-biphenyl]-4-yl)-[!,!' :4' ,1' '- terphenyl ] -4 , 4 ' ' -diamine (TaTm or NHT049) , N, N' -bis (naphthalen- 1-yl ) -N, N ' -bis (phenyl ) -benzidine (a-NPD) , MeO-TAD, spiro-MeO-TAD, HTM081, TDATA derivatives, and N3 , N3 ' -di (biphenyl ( -4 -yl ) -N3 , N3 ' - dimesitylbiphenyl-3 , 3 ' -diamine (HT3) .

[0041] According to a further development of the invention, the p-type layer comprises a p-dopant with a LUMO more negative than -4.5 eV, preferably more negative than -4.7 eV, preferably more negative than -4.9 eV, preferably more negative than -5.0 eV, or preferably more negative than -5.1 eV. The p-dopant of the p-type layer is preferably an organic dopant. In a preferred embodiment, the p-dopant of the p-type layer is selected from the group consisting of NDP2, NDP9, C60-F36, and C60-F48. NDP2 and NDP9 are commercial p-dopants from Novaled GmbH.

[0042] According to a further development of the invention, it is provided that the n-doped intermediate layer has an electron affinity of greater than 4.5 eV, preferably greater than 4.6 eV, preferably greater than 4.7 eV, preferably greater than 4.8 eV, or preferably greater than 4.9 eV, wherein the n-doped intermediate layer preferably has a proportion of the matrix material of at most 98.5 vol.%, preferably of at most 98 vol.%, preferably of at most 97 vol.%, preferably of at most 96 vol.%, or preferably of at most 95 vol.%.

[0043] The materials selected for the n-doped intermediate layer must be those that exhibit no or minimal diffusion, so that no diffusion into neighboring layers occurs. The n-doped intermediate layer, in particular, prevents the materials of the n-type layer and the p-type layer from mixing.

[0044] In a preferred embodiment, the matrix material of the n-doped intermediate layer is a chemical compound of the general formula I wherein Ri to Re is H or a substituent selected from the group consisting of a halogen, nitrile (— CN), nitro (— NO2), sulfonyl (— SO2R), sulfoxide (— SOR), trifluoromethyl (— CF3), ester (— CO— OR), amide (— CO— NHR or — CO— NRR'), substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, and substituted or unsubstituted alkyl, wherein R and R' may be a substituted or unsubstituted alkyl or aryl; or wherein Ri and R2, R3, and R4, or R5 and Re each form a ring structure, wherein the ring structure may be an aromatic ring, a heteroaromatic ring, or an aliphatic ring, and each ring may be substituted or unsubstituted.

[0045] According to a further development of the invention, it is provided that the matrix material of the n-doped intermediate layer is selected from the group consisting of hexaazatriphenylene, preferably with six electron-withdrawing substituents, preferably dipyrazino [2,3-f:2',3'-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile (CN-HAT), tetracyanobenzoquinonedimethane (TCNQ), tetracyanonaphthoquinonedimethane (TCNNQ), radialene, and derivatives thereof. According to a further development of the invention, it is provided that the n-dopant of the n-doped intermediate layer has a HOMO more negative than -4.6 eV, preferably more negative than -4.8 eV, or preferably more negative than -5.0 eV.

[0046] According to a further development of the invention, it is provided that the proportion of the n-dopant in the n-doped intermediate layer is 1 to 30 vol.%, preferably 1 to 20 vol.%, preferably 1 to 10 vol.%, preferably 1 to 5 vol.%, preferably 2 to 30 vol.%, preferably 5 to 30 vol.%, preferably 2 to 20 vol.%, preferably 2 to 10 vol.%, preferably 2 to 5 vol.%, preferably 3 to 30 vol.%, preferably 3 to 20 vol.%, preferably 5 to 20 vol.%, preferably 3 to 10 vol.%, or preferably 3 to 5 vol.%.

[0047] According to a further development of the invention, it is provided that the n-dopant of the n-doped intermediate layer has an ionization energy of 4.8 to 5.4 eV, preferably of 5.0 to 5.4 eV, preferably of 4.8 to 5.2 eV, or preferably of 5.0 to 5.2 eV.

[0048] According to a further development of the invention, the n-dopant of the n-doped intermediate layer is selected from the group consisting of pentacene or derivatives thereof, TDATA or derivatives thereof, preferably m-MTDATA, TAD or derivatives thereof, preferably spiro-MeO-TAD, BPBPA or derivatives thereof, TNATA or derivatives thereof, preferably 2-TNATA, TPD or derivatives thereof, preferably MeO-TPD, and triarylamine derivatives having at least one alkyl or alkoxy substituent on at least two aryl substituents of the amine. The n-dopant of the n-doped intermediate layer is preferably an organic dopant.

[0049] In a preferred embodiment, the matrix material of the n-type layer is an electron transport material (ETM).

[0050] According to a further development of the invention, it is provided that the n-type layer in the conversion contact of an organic photovoltaic element (OPV) has an electron affinity of less than 4.2 eV, preferably less than 4.0 eV, wherein the electron transport material of the n-type layer is preferably selected from the group consisting of a fullerene and / or a fullerene derivative, preferably fullerene C60 or C70, NTCDA, TNATA, and NTCDI or a derivative thereof.

[0051] According to a further development of the invention, it is provided that the n-dopant of the n-type layer in the conversion contact of an organic photovoltaic element (OPV) has a HOMO more positive than -5.0 eV, preferably more positive than -4.8 eV, or preferably more positive than -4.7 eV.

[0052] The n-dopant of the n-type layer is preferably an organic dopant. In a preferred embodiment, the n-dopant of the n-type layer is selected from the group consisting of 2,2'-diisopropyl-1,1',3,3'-tetramethyl-2,2',3,3',4,4',5,5',6,6',7,7'-dodecahydro-2,2'-bibenzo[d]imidazole (NDR-1); 4,4',5,5'-tetracyclohexyl-1,1',2,2',3,3'-hexamethyl-2,2',3,3'-tetrahydro-2,2'-biimidazole (NDR-2); 2, 2 '-diisopropyl-4, 4 ', 5, 5 '-tetrakis (2-methoxyphenyl) -1, 1 ', 3, 3 '-tetramethyl-2, 2 ', 3, 3 '-tetrahydro-1H, 1 'H-2,2'-biimidazole (NDR-3); 2,2'-diisopropyl-1, 1', 3, 3'-tetramethyl-2, 2', 3, 3'-tetrahydro-lH, l'H-2,2'-bibenzo[d]imidazole (NDR-4); 2,2'-diisopropyl-4, 4',5,5'-tetrakis (3-methoxyphenyl)-l,l',3,3'-tetramethyl-2, 2', 3, 3'-tetrahydro-lH, 1' H-2, 2'-biimidazole (NDR-5); 2-Isopropyl-1,3-dimethyl-2,3,6,7-tetrahydro-5,8-dioxa-l,3-diaza-cyclopenta[b]naphthene;Bis-[1,3-dimethyl-2-isopropyl-l,2-dihydro-benzoimidazolyl-(2)]; 2,2'-Diisopropyl-4, 5-bis(2-methoxyphenyl)-4',5'-bis(4-methoxyphenyl)-1,1',3,3'-tetramethyl-2,2',3,3'-tetrahydro-2,2'-biimidazole, and NDN45.;

[0053] In a particularly preferred embodiment, the matrix material of the n-type layer is a fullerene or fullerene derivative. In a preferred embodiment, the at least one fullerene and / or fullerene derivative n-type layer in the conversion contact is selected from the group consisting of C60, C70, C76, C80, C82, C84, C86, C90 and C94, or a derivative thereof, wherein the derivative is preferably a halogenated fullerene, a hydroxylated fullerene, a carboxylated fullerene, or an aminated fullerene, particularly preferably the fullerene is C60 or C70 or a derivative thereof, particularly preferably C60.

[0054] According to a further development of the invention, it is provided that the difference between the electron affinity of the n-doped intermediate layer and the electron affinity of the n-type layer is at least 0.5 eV, preferably at least 0.6 eV, or preferably at least 0.7 eV.

[0055] According to a further development of the invention, it is provided that the difference between the ionization energy of the p-type layer and the electron affinity of the n-doped intermediate layer is greater than 0.3 eV and less than 1.0 eV, preferably greater than 0.5 eV and less than 0.8 eV.

[0056] According to a further development of the invention, it is provided that the n-doped intermediate layer has a layer thickness of 2 nm to 100 nm, preferably from 2 nm to 50 nm, preferably from 5 nm to 50 nm, preferably from 5 nm to 30 nm, or preferably from 10 nm to 40 nm.

[0057] In a preferred embodiment, the conversion contact is arranged directly on a photoactive layer, in particular directly on the first and second photoactive layer or directly on the second and a third photoactive layer.

[0058] In an alternative preferred embodiment, an electron transport layer or a hole transport layer is arranged between the conversion contact and a photoactive layer, in particular directly on the first and second photoactive layer or directly on the second and third photoactive layer.

[0059] According to a further development of the invention, it is provided that the n-doped intermediate layer is arranged in direct contact with the p-type layer, and / or the n-doped intermediate layer is arranged in direct contact with the n-type layer. In a preferred embodiment, the n-doped intermediate layer is not arranged in direct contact with the p-type layer, and / or the n-doped intermediate layer is not arranged in direct contact with the n-type layer.

[0060] According to a further development of the invention, it is provided that an intrinsic layer is arranged between the p-type layer and the n-doped intermediate layer and / or between the n-type layer and the n-doped intermediate layer.

[0061] In a particularly preferred embodiment, the intrinsic layer is arranged directly on the n-doped intermediate layer and directly on the p-type layer and / or the intrinsic layer is arranged directly on the n-doped intermediate layer and directly on the n-type layer.

[0062] In a preferred embodiment, an intermediate layer is arranged between the p-type layer and the n-doped intermediate layer, wherein the intrinsic layer has an ionization energy of 5.0 eV to 5.7 eV, preferably of 5.2 eV to 5.5 eV.

[0063] In a preferred embodiment, an intrinsic layer is arranged between the n-type layer and the n-doped intermediate layer, wherein the intrinsic layer has an electron affinity of 4.0 eV to 5.0 eV, preferably of 4.0 eV to 4.5 eV.

[0064] In a preferred embodiment, the intrinsic layer is formed from a material and / or is a non-doped layer.

[0065] According to a further development of the invention, it is provided that the intrinsic layer has a layer thickness of 1 nm to 10 nm, preferably of 1 nm to 5 nm, or preferably of 1 nm to 2 nm.

[0066] In a preferred embodiment, the intrinsic layer between the n-type layer and the n-doped intermediate layer is formed from a fullerene and / or a fullerene derivative, preferably fullerene C60, and the intrinsic layer between the p-type layer and the n-doped intermediate layer is formed from a triarylamine derivative.

[0067] In a preferred embodiment, the material of the intrinsic layer arranged on the n-type layer is the matrix material of the n-type layer. In a preferred embodiment, the material of the intrinsic layer arranged on the p-type layer is the matrix material of the p-type layer.

[0068] In a preferred embodiment, the intrinsic layer is formed from one material or a mixture of several materials. In a particularly preferred embodiment, the material of the intrinsic layer is

[0069] In a preferred embodiment, the material of the intrinsic layer is selected from BPBPA, a fullerene or fullerene derivative, C60 and NHT049. In a preferred embodiment, the at least one fullerene and / or fullerene derivative of the intrinsic layer is selected from the group consisting of C60, C70, C76, C80, C82, C84, C86, C90 and C94, or a derivative thereof, wherein the derivative is preferably a halogenated fullerene, a hydroxylated fullerene, a carboxylated fullerene, or an aminated fullerene, particularly preferably the fullerene is C60, C70 and / or a derivative thereof, particularly preferably C60.

[0070] In a preferred embodiment, the intrinsic layer has a proportion of the fullerene and / or fullerene derivative of at least 50 vol.%, preferably at least 60 vol.%, preferably at least 70 vol.%, preferably at least 75 vol.%, preferably at least 80 vol.%, preferably at least 85 vol.%, preferably at least 90 vol.%, or preferably at least 95 vol.%, preferably at least 96 vol.%, preferably at least 97 vol.%, preferably at least 98 vol.%, particularly preferably the at least one intermediate layer consists of the fullerene and / or fullerene derivative.

[0071] According to a further development of the invention, it is provided that the first photoactive layer and / or the second photoactive layer have at least one donor and at least one acceptor which form a donor-acceptor system, wherein preferably the at least one donor is an ADA oligomer and / or a BODIPY, and preferably the at least one acceptor is an ADA oligomer and / or a fullerene and / or fullerene derivative.

[0072] A BODIPY compound is understood in particular to be a compound of the general formula C9H7BN2F2, i.e. a compound having a boron difluoride group with a dipyrromethene group, in particular a compound 4,4-dif luoro-4-bora-3a,4a-diaza-s-indacene. An ADA oligomer is understood in particular to be a conj ugated acceptor-donor-acceptor oligomer (ADA' oligomer) with an acceptor unit (A) and a further acceptor unit (A'), each of which is bonded to a donor unit (D).

[0073] In a preferred embodiment, the photoactive layer has a layer thickness of 2 to 100 nm, preferably from 5 nm to 100 nm, preferably from 10 nm to 100 nm, preferably from 2 nm to 50 nm, preferably from 5 nm to 50 nm, or preferably from 10 nm to 50 nm.

[0074] In a preferred embodiment, the first electrode and / or the second electrode are made of indium tin oxide (ITO), indium zinc oxide (IZO), tin oxide (SnO2), aluminum zinc oxide (AlZO), ZnO (ZnO), or of metals Ag, Al or alloys thereof.

[0075] According to a development of the invention, it is provided that the first electrode and / or the second electrode is in direct contact or in diffusion contact with an adhesive layer, preferably an adhesive layer, a protective layer or a barrier layer, preferably an adhesive layer based on acrylates, epoxy resins or silicones, or an oxide layer is arranged between the first electrode and / or the second electrode and the adhesive layer, wherein the oxide layer preferably has a layer thickness of at most 200 nm, particularly preferably of at most 100 nm, or preferably of 10 nm to 200 nm, or preferably of 10 nm to 100 nm.

[0076] In a preferred embodiment, the adhesive layer between the layer system or the electrodes and the protective layer, in particular the encapsulation, is formed from a material selected from the group consisting of siloxanes, silicones, epoxies, in particular epoxy resins, acrylates, in particular cyanoacrylates or polymethyl methacrylate (PMMA), styrenes, and polyurethanes.

[0077] According to a further development of the invention, it is provided that the organic electronic component is an organic photovoltaic element, preferably an organic photovoltaic element encapsulated by polymer films, with the adhesive layer arranged between the polymer film and the first electrode and / or the second electrode.

[0078] In a preferred embodiment, the p-dopant of the p-type layer is selected from the group consisting of 2,2'-

[0079] <h2 style=";text-align:left;direction:ltr">(perf luorocyclohexa-2, 5-diene-l, 4-diylidene) dimalononitril (TCNQ- 1 ), N' -Di cyan- 2, 3, 5, 6-tetrafluoro-l, 4 -Chinondiimin; N. , 4- napht ho Chinondiimin, 1,4,5, 8-Tetrahydro-l , 4,5,8-tetrathia-2,3,6,7- tetracyano-anthrachinon, 1 , 3 , 4 , 5 , 7 , 8 -Hexa fluoro naphtho -2 , 6- chinontetracyanomethane (TCNQ-7) , 2 , 2 '-(2,5-Dibrom-3,6-difluorcyclobexa-2,5-dien-l,4-diyliden)dimalononitril,4,4'-<h2 style=";text-align:left;direction:ltr"> <h2 style=";text-align:left;direction:ltr">

[0080] ( IE , 1 ' E ) - ( 2 -cyano -3 , 6 -di fluoro -5 -isocyano cyclohexa- 2 ,5-diene-l,4- diylidene ) bis- ( cyanomethan-l-yl-l-ylidene )bis (2,3,5,6- tetraf luorobenzonitril ) , 2, 2 ',2"- (Cyclopropan-1 , 2 , 3 - triyliden) tris (2- (2, 6 -di chlor- 3 , 5-dif luor-4- (trifluormethyl ) phenyl )acetonitril) , (2E, 2' E, 2" E)-2, 2 ' , 2 "- ( cyclopropane-1 , 2, 3-triylidene ) tris (2-

[0081] (perf luorophenyl )acetonitril) , 2 , 2 ' , 2 " - ( cyclopropane- 1 , 2,3- triylidene) tris (2- ( perfluorobiphenyl -4 -yl )acetonitril) , 2 , 2 ' , 2 " - ( cyclopropane- 1 , 2, 3-triylidene) tris (2- (2, 6-dichloro-3 , 5-dif luoro- 4- (trifluoromethyl) phenyl) -acetonitril ) , und Benzeneacetonitril, a, o' , o"-l , 2 , 3 -cyclopropane triylidene tris [4-cyano-2,3,5, 6- tetraf luoro- ( PR-1 ) .

[0082] In a preferred embodiment, the at least one photoactive layer and the second photoactive layer comprise, as absorber material, a donor-acceptor system which is designed as a bulk heterojunction (BHJ) or planar heterojunction (PHJ).

[0083] In a preferred embodiment, the at least one photoactive layer comprises small molecules as absorber material. Small molecules are understood to be, in particular, non-polymeric organic molecules with monodisperse molar masses between 100 and 2000 g / mol, which exist in the solid phase under normal pressure (atmospheric pressure of the surrounding atmosphere) and at room temperature.

[0084] The organic electronic component according to the invention with a conversion contact having an n-doped intermediate layer between two photoactive layers has advantages compared to the prior art. Advantageously, the lifetime of organic electronic components with at least two photoactive layers is increased, in particular a decrease in efficiency over time is reduced. Advantageously, the lifetime under thermal stress is increased. Advantageously, the decrease in the fill factor (FF) over time, in particular at elevated temperature, is reduced compared to corresponding organic electronic components with a conversion contact without the n-doped intermediate layer, in particular without a further intrinsic layer. Advantageously, in particular the lifetime of photovoltaic elements encapsulated by means of an adhesive layer and a protective layer is increased.

[0085] The object of the present invention is also achieved by providing a use of a conversion contact according to the invention between two photoactive layers of an organic electronic component, in particular according to one of the previously described embodiments. The use of the conversion contact in the organic electronic component results in particular in the advantages already explained in connection with the organic electronic component.

[0086] In a preferred embodiment, the layer system has at least two, preferably at least three, or preferably at least four photoactive layers, wherein the conversion contact is arranged between at least two adjacent photoactive layers. The organic electronic component is designed as a tandem cell, triple cell or multiple cell, wherein a conversion contact is arranged between at least two photoactive layers. In the case of three or more photoactive layers, the conversion contacts can each be designed differently between adjacent photoactive layers.

[0087] In a preferred embodiment, the organic electronic component is an organic photovoltaic element (OPV), a sensor, or an organic photodetector.

[0088] The object of the present invention is also achieved by providing an encapsulated organic electronic component, preferably an encapsulated organic photovoltaic element, with a conversion contact between two photoactive layers, in particular according to one of the previously described embodiments. The organic electronic component is encapsulated by means of at least one polymer film, with an adhesive layer being arranged between the at least one polymer film and an electrode and / or the layer system of the organic electronic component. This results in particular in the advantages for the encapsulated organic electronic component that have already been explained in connection with the organic electronic component. One of the electrodes and / or the layer system is in direct contact or in diffusion contact with the adhesive layer.

[0089] In a preferred embodiment, the first electrode and / or the second electrode and / or the layer system is in direct contact and / or in diffusion contact with the adhesive layer.

[0090] Direct contact of an adhesive layer with the electronic component is understood to mean, in particular, direct contact of the adhesive layer with an electrode and / or the layer system of the organic electronic component. Direct contact with the layer system can occur, for example, due to an incomplete arrangement of an electrode on the layer system, due to laser structuring of the layer system, or due to cracks in an electrode and / or a protective layer arranged on the electrode.

[0091] A diffusion contact of the adhesive layer with the electronic component is understood to mean, in particular, an indirect contact of at least one component of the adhesive layer via at least one intermediate material, in particular at least one intermediate layer arranged between the adhesive layer and the electronic component, with an electrode and / or the layer system of the electronic component, wherein a component of the adhesive layer can penetrate the at least one intermediate material, in particular the at least one intermediate layer.

[0092] The invention is explained in more detail with reference to the following exemplary embodiments and figures. In particular, it was demonstrated in the following exemplary embodiments that a conversion contact according to the invention with an n-doped intermediate layer between the n-type layer and the p-type layer of the conversion contact increases the lifetime of an organic optoelectronic component. These figures show:

[0093] Fig. 1 shows, in one embodiment, a schematic representation of a layer system of an organic electronic component with a layer system with two photoactive layers in cross section;

[0094] Fig. 2 shows, in one embodiment, a schematic representation of a layer system of an organic electronic component with a conversion contact with an n-doped intermediate layer between two photoactive layers in cross section;

[0095] Fig. 3 shows, in one embodiment, a schematic representation of a layer system of an organic electronic component with a conversion contact arranged between two photoactive layers with an n-doped intermediate layer and an intrinsic layer in cross section;

[0096] Fig. 4 shows, in one embodiment, a schematic representation of a layer system of an organic electronic component with a conversion contact arranged between two photoactive layers with an n-doped intermediate layer and an intrinsic layer in cross section;

[0097] Fig. 5 shows, in one embodiment, a schematic representation of a layer system of an organic electronic component with three photoactive layers and a conversion contact with an n-doped intermediate layer in cross section;

[0098] Fig. 6 shows, in one embodiment, a schematic representation of a layer system of an organic electronic component with three photoactive layers and a conversion contact with an n-doped intermediate layer and an intrinsic layer in cross section;

[0099] Fig. 7 shows, in one embodiment, a schematic representation of a layer system of an organic electronic component with three photoactive layers and each with a conversion contact with an n-doped intermediate layer between the photoactive layers in cross section; and

[0100] Fig. 8 shows, in one embodiment, a schematic representation of a layer system of an organic electronic component with three photoactive layers and each one

[0101] Conversion contact with an n-doped intermediate layer and an intrinsic layer between adjacent photoactive layers in cross section.

[0102] In particular, it is shown that an organic electronic component with a conversion contact according to the invention with an n-doped intermediate layer has an improved lifetime compared to a conversion contact without an intermediate layer. This shows an increased lifetime under thermal stress, with the efficiency being reduced to a lesser extent compared to connection units known from the prior art. The following chemical compounds from the class of small molecules were used as donors in the photoactive layers, in particular in the donor / acceptor system, in the exemplary embodiments:

[0103] Donor2

[0104] o nor 4

[0105] Donor1 and Donor3 are BODIPY compounds, and Donor2 and Donor4 are ADA oligomers. In all figures, identical and functionally equivalent elements are designated by the same reference numerals, so reference is made to the previous description.

[0106] Examples of implementation

[0107] Fig. 1 shows, in one exemplary embodiment, a schematic representation of an organic electronic component 50 with a layer system 20 with two photoactive layers 4, 7 from the prior art, in cross section. The layer thickness and the ratio of the layer thicknesses to one another do not correspond to the actual dimensions. The organic optoelectronic component 50 is a photovoltaic element in this exemplary embodiment.

[0108] An organic electronic component 50 known from the prior art has a first electrode 2, a layer system 20, and a second electrode 9 on a substrate 1, wherein the layer system 20 is arranged between the first electrode 2 and the second electrode 9. The layer system 20 has a first photoactive layer 4 and a second photoactive layer 7, an electron transport layer (ETL) 3 is arranged between the first electrode 2 and the first photoactive layer 4, and a hole transport layer (HTL) 8 is arranged between the second electrode 9 and the second photoactive layer 7.The first electrode 2 is made of transparent indium tin oxide (ITO), but alternatively, an electrode made of a metal, in particular Al, Ag, Au or a combination thereof, a conductive oxide, in particular ITO, ZnO:Al, or a conductive oxide, or a conductive polymer, such as PEDOT:PSS (poly(3,4-ethylenedioxythiophene) poly(synthetic sulfonate) or PANI (polyaniline)) is also possible. The electron transport layer (ETL) 3 is made of C60, for example, doped with NDN45. The first photoactive layer 4 and the second photoactive layer 7 have at least one donor and at least one acceptor, which together form a donor-acceptor system as a bulk heterojunction (BHJ) or as a planar heterojunction. A connecting unit, a so-called pn junction, is arranged between the two photoactive layers. composed of a p-type layer and an n-type layer.The hole transport layer (HTL) 8 is formed, for example, from fullerene C60 or doped fullerene C60. The second electrode 9 is made of a metal, for example, Al or Au.

[0109] Example A

[0110] Fig. 2 shows a schematic cross-sectional view of a layer system 20 of an organic electronic component 50 with a conversion contact 30 having an n-doped intermediate layer 10 between two photoactive layers 4, 7. In this exemplary embodiment, the organic electronic component 50 is an organic photovoltaic element.

[0111] The organic electronic component 50 has a first electrode 2, a second electrode 9, and a layer system 20 arranged between the first electrode 2 and the second electrode 9, comprising a first photoactive layer 4 and a second photoactive layer 7. A conversion contact 30 is arranged between the first photoactive layer 4 and the second photoactive layer 7. The conversion contact 30 comprises layers arranged in the following order: a) a doped or undoped p-type layer 5 with an optical band gap of greater than 2.5 eV, wherein the p-type layer 5 has an ionization energy of greater than 5.0 eV; b) an n-doped intermediate layer 10 with a matrix material and at least one n-dopant, wherein the n-doped intermediate layer 10 has an electron affinity of greater than 4.4 eV, and wherein the proportion of the at least one n-dopant is 1 to 30 vol.-%; and c) a doped n-type layer 6 with an electron transport material (ETM) and at least one n-dopant, wherein the n-type layer 6 has an electron affinity of less than 4.4 eV. This results in particular in an improved lifetime of the organic electronic component 50, in particular a lower loss of efficiency of the organic electronic component 50 over time. The structure of such an organic electronic component 50 is described in Table A1. The organic electronic component 50 has, on a substrate 1, e.g. glass or PET film, a first electrode 2, e.g. ITO, a first photoactive layer 4, a second photoactive layer 7, and a second electrode 9, e.g. Al, wherein the first photoactive layer 4 and the second photoactive layer 7 are arranged between the first electrode 2 and the second electrode 9.An electron transport layer (ETL) 3 is arranged between the first electrode 2 and the first photoactive layer 4, and a hole transport layer (HTL) 8 is arranged between the second electrode 9 and the second photoactive layer 7. The conversion contact 30 with the n-doped intermediate layer 10 is arranged between the first photoactive layer 4 and the second photoactive layer 7. The photoactive layers 4, 7 are designed as a bulk heterojunction (BHJ), but can alternatively also be designed as a planar heterojunction (PHJ). The first photoactive layer 4 and the second photoactive layer 7 are each formed from the absorber materials Donor4 and C60. The two comparative examples Ala and Alb show conversion contacts known from the prior art, a conversion contact without an intermediate layer and a conversion contact without an intermediate layer.a conversion contact with a non-doped intermediate layer of CN-HAT in direct contact with the n-type layer and the p-type layer of the pn-junction (see Table A1). A1e and A11 relate to conversion contacts 30 according to the invention. The conversion contacts 30 according to the invention have an n-doped intermediate layer 10 arranged between the n-type layer 6 and the p-type layer 5, formed from CN-HAT (electron affinity of 5.0 eV) as matrix material in a doping with TNATA of 20% by weight or 50% by weight.

[0112] In one embodiment of the invention, materials selected from the group consisting of hexaazatriphenylene, preferably with six electron-withdrawing substituents, tetracyanobenzoquinone dimethane, tetracyanonaphtho chinon dimethane, radialene, perylenetetracarboxylic dianhydride (PTCDA) and derivatives thereof can alternatively be used as the matrix material of the n-doped intermediate layer.

[0113] In one embodiment of the invention, as an alternative to TNATA as the n-dopant of the n-doped intermediate layer 10, materials selected from the group consisting of pentacene or derivatives thereof, TDATA or derivatives thereof, preferably m-MTDATA, TAD or derivatives thereof, preferably spiro-MeO-TAD, BPBPA or derivatives thereof, derivatives of TNATA, preferably 2-TNATA, TPD or derivatives thereof, preferably MeO-TPD, and triarylamine derivatives having at least one alkyl or alkoxy substituent on at least two aryl substituents of the amine can be used.

[0114] Table Al

[0115]

[0116] ITO : Indium Tin Oxide

[0117] NDP9: commercial p-dopant from Novaled GmbH

[0118] NHT49: commercial hole conductor from Novaled GmbH NDN45: commercial n-dopant from Novaled GmbH HTM081: is a commercial HTL matrix material from Merck AG (Merck SHT-218)

[0119] The p-type layer 5 has the matrix material NHT049 with an ionization energy of 5.4 eV. The p-type layer 5 has the p-dopant NDP9 with a LUMO of 5.4 eV. The n-doped intermediate layer 10 with CN-HAT as matrix material has an electron affinity of 5.0 eV. The n-dopant TNATA of the n-doped intermediate layer 10 has an ionization energy of 5.0 eV. The n-type layer 6 of the conversion contact 30 with C60 as matrix material has an electron affinity of 4.0 eV. The n-dopant NDN45 of the n-type layer 6 has a HOMO of -4.56 eV.

[0120] The current-voltage characteristics of the organic photovoltaic elements were measured. The parameters of the organic photovoltaic elements were measured under simulated AMI 0.5 illumination (AM = Air Mass; AM = 1.5). In this spectrum, the global radiant power is 1000 W / m 2(AM = 1.5 as standard value for measuring solar modules). The lamp irradiates the sample in such a way that the second electrode is facing away from the light. From this, the parameters open-circuit voltage (Voc), short-circuit current (Jsc), and fill factor (FF) were determined, and the relative efficiency (power conversion efficiency, PCE), which is a measure of the efficiency of the organic photovoltaic elements, was determined.

[0121] Both the known conversion contacts Ala and Alb, and the conversion contacts Ale and A11 according to the invention show a good initial efficiency (PCE). The initial efficiency of the comparative example Ala is the best, but the efficiency of the comparative examples decreases significantly more sharply after 1000 hours of aging compared to a conversion contact 30 according to the invention with an n-doped intermediate layer 10. Compared to the known conversion contacts, the efficiency of the photovoltaic elements with a conversion contact 30 according to the invention is significantly higher after aging, which is due in particular to a lower loss of the fill factor (FF). The two comparative examples with a known conversion contact without an n-doped intermediate layer show a reduced service life. The aging to determine the service life of a photovoltaic element was tested at dry heat 85 °C for 1000 hours, i.e.Current-voltage characteristics were measured under simulated AMI 5 illumination to determine the photoelectric parameters before and after aging.

[0122] The doping concentration of the n-type layer 6 of the conversion contact 30 can be reduced by using an n-doped intermediate layer 10. Compared to the Al embodiment, the doping of the matrix material C60 of the n-type layer 6 with NDN45 was reduced from 20 wt. % to 5 wt. % (see Table A2).

[0123] Table A2

[0124] The organic photovoltaic element with a lower doping of the n-type layer 6 (A2b) adjacent to the n-doped intermediate layer 10 shows a higher initial efficiency compared to the comparative example with a conversion contact without an n-doped intermediate layer (A2a). In addition, in the comparative example the efficiency decreases significantly more after 1000 hours of aging compared to that with the conversion contact 30 according to the invention, which is due in particular to the greater loss of the fill factor (FF). Even with a lower doping of the n-type layer 5, the efficiency is high due to the conversion contact 30. The n-doped intermediate layer 10 within the conversion contact 30 leads to a significantly more stable layer system 20 and increases the service life of the organic photovoltaic element.Furthermore, the n-doped intermediate layer 10 in the conversion contact 30 can reduce the concentration of the dopant in the adjacent n-type layer 6.

[0125] In this embodiment, the n-doped intermediate layer 10 is arranged in direct contact with the p-type layer 5 and in direct contact with the n-type layer 6.

[0126] To produce the organic electronic component 50 with the electrodes 2, 9 and the layer system 20, vacuum evaporation of the individual layers of the layer system 20 and the electrodes 2, 9 was used in the present exemplary embodiments. The materials can be applied to the substrate or previous layers by evaporating the corresponding material in a vacuum. In the process, the layers of the layer system are formed step by step. To form the doped layers, the matrix material was co-evaporated with the dopant. To deposit the photoactive layers 4, 7 formed as a bulk heterojunction, the donor and the acceptor of the heterojunction were co-evaporated. The materials of the individual layers can therefore be processed in a vacuum.Alternatively, production is possible by processing the materials in a solvent, for example spin-coating, by a printing process, or by deposition using slot-die coating.

[0127] The deposition rate was 0.2 Å / s for the photoactive layers 4, 7 and 1.0 Å / s for the layers of the conversion contact 30. However, deposition of the layers at a higher or lower deposition rate is also possible, preferably in the range of 0.1 to 10 Å / s.

[0128] Example B

[0129] In this exemplary embodiment, the layer system 20 has a structure according to Fig. 2. In comparison to exemplary embodiment A, the n-dopant m-MTDATA (ionization energy of 5.0 eV) was used in the n-doped intermediate layer 10 of the conversion contact 30 instead of TNATA. Furthermore, in this exemplary embodiment, the organic photovoltaic element is encapsulated with a polymer film, with an adhesive layer made of acrylate being arranged between the polymer film and the electrodes 2, 9 and / or the layer system 20. The electrodes 2, 9 and / or the layer system 20 are in direct contact or in diffusion contact with the adhesive layer.

[0130] The first photoactive layer 4 and the second photoactive layer 7 are each formed as a bulk heterojunction (BHJ).

[0131] Table B

[0132]

[0133] Both an organic photovoltaic element with a known conversion contact (Ba) and with a conversion contact according to the invention (Bb) exhibit good initial efficiency (PCE). However, after 1000 hours of aging, the efficiency of the organic photovoltaic element with a conversion contact without an n-doped intermediate layer as comparative example Ba decreases significantly, whereas the efficiency with an inventive conversion contact 30 with an n-doped intermediate layer 10 decreases only slightly over time, which is due in particular to a lower loss of the fill factor (FF). The n-doped intermediate layer 10 within the conversion contact 30 increases the service life of the organic photovoltaic element compared to the comparative example. Embodiment C

[0134] In this exemplary embodiment, the photovoltaic element has a tandem cell with a conversion contact 30 arranged between the photoactive layers 4, 7 and having an n-doped intermediate layer 10. In comparison to exemplary embodiment A, the n-doped intermediate layer 10 of the conversion contact 30 is formed from the matrix material CN-HAT and doped with 2 wt. % m-MTDATA. In one embodiment, the n-doped intermediate layer 10 of the conversion contact 30 is arranged directly on the n-type layer 6 and the p-type layer 5 (Ca). In a further embodiment, an intrinsic layer 11 is additionally arranged in the conversion contact 30 between the n-type layer 6 and the n-doped intermediate layer 10 (Cb), or an intrinsic layer 12 is arranged between the p-type layer 5 and the n-doped intermediate layer 10 (Cc). The intrinsic layer 11,12 is not doped.

[0135] In the p-type layer 5, the matrix material HT3 has an ionization energy of 5.52 eV and the matrix material NHT049 has an ionization energy of 5.4 eV. The p-type layer 5 has the p-dopant NDP9 with a LUMO of 5.4 eV. The n-doped intermediate layer 10 with CN-HAT as the matrix material has an electron affinity of 5.0 eV. The n-dopant m-MTDATA of the n-doped intermediate layer 10 has an ionization energy of 5.0 eV. The n-type layer 6 of the conversion contact 30 with C60 as the matrix material has an electron affinity of 4.0 eV. The n-dopant NDN45 of the n-type layer 6 has a HOMO of -4.56 eV. The intrinsic layer 11 made of C60 has an electron affinity of 4.0 eV. The intrinsic layer 12 made of NHT049 has an electron affinity of 5.4 eV.

[0136] Table C

[0137]

[0138] ITO : Indium Tin Oxide

[0139] NDP 9 : commercial p-dopant of Novaled GmbH

[0140] NHT49 : commercial hole conductor of Novaled GmbH

[0141] NDN45 : commercial n-dopant of Novaled GmbH

[0142] HT3: (N3, N3'-Di(biphenyl(-4-yl)-N3, N3'-dimesitylbiphenyl-3, 3'-diamine)

[0143] Fig. 3 and 4 show a schematic representation of such a layer system 20 of an organic electronic component 50 with a conversion contact 30 arranged between two photoactive layers 4, 7 with an n-doped intermediate layer 10 and an intrinsic layer 11 or 12 in cross section.

[0144] In Fig. 3, an additional intrinsic layer 11 is arranged in the conversion contact 30 with the n-doped intermediate layer 10 between the n-type layer 6 and the n-doped intermediate layer 10, as in (Cb). The n-type layer 6 is therefore not in direct contact with the n-doped intermediate layer 10.

[0145] In Fig. 4, the conversion contact 30 with the n-doped intermediate layer 10 is arranged between the p-type layer 5 and the n-doped intermediate layer 10, along with an additional intrinsic layer 12, as in (Cc). The p-type layer 5 is therefore not in direct contact with the n-doped intermediate layer 10.

[0146] All embodiments Ca to Cc have an n-doped intermediate layer 10 in the conversion contact 30 and show only a slight loss of efficiency after 1000 hours of aging. However, the additional intrinsic layer 11, 12 in the embodiments Cb and Cb leads to a further stabilization of the layer system, as can be seen from the higher efficiency compared to a conversion contact 30 with an n-doped intermediate layer 10 without an intrinsic layer. The efficiency with an additional intrinsic layer between the n-type layer 6 and the n-doped intermediate layer 10 (Cb) or the p-type layer 5 and the n-doped intermediate layer 10 (Cc) decreases less during aging compared to a conversion contact 30 with an n-doped intermediate layer 10 but without a further intrinsic layer.Similar experimental data were also obtained using other dopants, such as BPBPA, to dope the intermediate layer of the conversion contact.

[0147] In a further embodiment, an intrinsic layer 12 can be arranged between the p-type layer 5 and the n-doped intermediate layer 10 and an intrinsic layer 11 can be arranged between the n-type layer 6 and the n-doped intermediate layer 10 of the conversion contact 30.

[0148] In a further embodiment, the conversion contact 30 with the n-doped intermediate layer 10 or 16 can be arranged between adjacent photoactive layers 4, 7 and / or 7, 15 of a so-called triple cell. Fig. 5 shows a schematic representation of such a layer system 20 of an organic electronic component 50 with three photoactive layers 4, 7, 15 and a conversion contact 30 with an n-doped intermediate layer 10 between the photoactive layers 4, 7 in cross section.

[0149] In a further embodiment, an intrinsic layer 11 can additionally be arranged between the n-type layer 6 or 14 and the n-doped intermediate layer 10 or 16 and / or an intrinsic layer 12 between the p-type layer 5 or 13 and the n-doped intermediate layer 10 or 16 of the conversion contact 30. Fig. 6 shows a schematic representation of such a layer system 20 of an organic electronic component 50 with three photoactive layers 4, 7, 15 and a conversion contact 30 with an n-doped intermediate layer 10 and an intrinsic layer 11 between the adjacent photoactive layers 4, 7 in cross section.

[0150] Example D

[0151] This embodiment shows an organic photovoltaic element with three photoactive layers 4, 7, 15. In embodiment (Da), the photovoltaic element has a conversion contact 30 with an n-doped intermediate layer 10 between each photoactive layer 4, 7 and 7, 15. The three photoactive layers 4, 7, 15 each have different absorbers (Donor 1 / C60; Donor 2 / C60; Donor 3 / C60), each configured as a bulk heterojunction and forming a donor / acceptor system. The n-doped intermediate layer 10 of the conversion contact 30 is made of CN-HAT doped with m-MTDATA.

[0152] In a comparative example (Db), the organic photovoltaic element has conversion contacts 30 without an n-doped intermediate layer 10 (pn-unction) between the three photoactive layers 4,7,15.

[0153] Table Da

[0154] Fig. 7 shows a schematic representation of such a layer system 20 of an organic electronic component 50 with three photoactive layers 4, 7, 15 and one conversion contact 30 each with an n-doped intermediate layer 10, 16 between the photoactive layers 4, 7, 15 in cross section.

[0155] In the comparative example (Db), the conversion contact between the first photoactive layer 4 and the second photoactive layer 7 is formed from a simple pn-junction, and the conversion contact between the second photoactive layer 7 and the third photoactive layer 15 is formed from a pn-junction with a p-HTL layer additionally arranged between the p-type layer and the n-type layers, i.e. two adjacent p-type layers.

[0156] Table Db

[0157] ITO : Indium Tin Oxide

[0158] NDP 9 : commercial p-dopant of Novaled GmbH

[0159] NHT49 : commercial hole conductor of Novaled GmbH

[0160] NDN45 : commercial n-dopant of Novaled GmbH

[0161] HTM081 : is a commercial HTL matrix material from Merck AG (Merck SHT-218 )

[0162] The experimental data show slower aging of the photovoltaic element with a conversion contact 30 according to the invention with an n-doped intermediate layer 10 between the adjacent photoactive layers 4, 7 and 7, 15 (Da) compared to the comparative example. While the initial efficiency of both photovoltaic elements is similar, almost no loss of efficiency is observed after 1000 hours of aging in the photovoltaic element with the conversion contact 30 according to the invention. The conversion contact 30 with an n-doped intermediate layer 10 enables better efficiency and improved stability even in a triple cell compared to the comparative example.

[0163] In one embodiment, alternatively or additionally, an intrinsic layer 11 can be arranged between the n-type layer 6 and the n-doped intermediate layer 10 and / or an intrinsic layer 12 can be arranged between the p-type layer 5 and the n-doped intermediate layer 10.

[0164] Fig. 8 shows a schematic representation of such a layer system 20 of an organic electronic component 50 with three photoactive layers 4, 7, 15 and in each case a conversion contact 30 with an n-doped intermediate layer 10, 16 and an intrinsic layer 11, 17 between adjacent photoactive layers 4, 7, 15 in cross section.

[0165] Example E

[0166] In this exemplary embodiment E, both layer systems 20 have a conversion contact 30 according to the invention with an n-doped intermediate layer 10. In exemplary embodiment (Eb), the structure of the layer system 20 of the photovoltaic element largely corresponds to that of exemplary embodiment (Cc), and exemplary embodiment (Ea) largely corresponds to that of exemplary embodiment (Ca), with BPBPA (ionization energy of 5.35 eV) being used in the p-type layer 5 and in the intrinsic layer 12 of the conversion contact 30 instead of the matrix material NHT049. The exemplary embodiment (Ea) has no intrinsic layer 12 in the conversion contact 30. The exemplary embodiment (Eb) has an intrinsic layer 12 made of BPBPA in the conversion contact 30 between the n-doped intermediate layer 10 and the p-type layer 5. The first photoactive layer 4 and the second photoactive layer 7 are each formed as a planar heterojunction (PHJ).

[0167] Table E

[0168]

[0169] In both embodiments with a conversion contact 30 with an n-doped intermediate layer 10, the efficiency decreases only slightly during aging. The additional intrinsic layer 12 in embodiment (Eb) leads to an even smaller decrease in efficiency during aging compared to embodiment (Ea), thus further stabilizing the layer system 20.

[0170] Example F

[0171] In this exemplary embodiment, a photovoltaic element with a tandem cell and a conversion contact with a non-doped intermediate layer (Fb) arranged between the two photoactive layers 4, 7 was compared with such a photovoltaic element with conversion contacts 30 with an n-doped intermediate layer 10 (Fa, Fc, Fd), wherein m-MTDATA, BPBPA, and NHT49 were used as dopants of the n-doped intermediate layer 10. The structure of the layer system corresponds to that shown in Fig. 2.

[0172] Table F

[0173]

[0174] Photovoltaic elements with an n-doped intermediate layer 10 with m-MTDATA, BPBPA or NHT049 in the conversion contact 30 with CN-HAT as matrix material between two photoactive layers 4 , 7 ( Fa , Fc and Fd ) show a higher initial efficiency and an improved

[0175] Lifespan .

[0176] Example G

[0177] Shows a layer system 20 of a photovoltaic element with two photoactive layers 4, 7 and a conversion contact 30 arranged therebetween with an n-doped intermediate layer 10. The donor / acceptor system of the first photoactive layer 4 is formed from C60 and Donor2, and the donor / acceptor system of the second photoactive layer 7 is formed from C60 and Donor3.

[0178] The layer thickness of the n-doped intermediate layer 10 was varied from 5 nm to 35 nm, and the layer thickness of the p-type layer 5 was also varied, while the total layer thickness of the entire conversion contact 30 was kept constant at 100 nm.

[0179] Table G

[0180] The experimental data show only a small difference in the initial efficiency of the photovoltaic element at different layer thicknesses of the n-doped intermediate layer 10 of the conversion contact 30 and also in the efficiency after 1000h aging.

[0181] The exemplary embodiments show the longer service life of organic photovoltaic elements with a conversion contact 30 according to the invention with an n-doped intermediate layer 10 between two photoactive layers 4, 7 in comparison to corresponding organic photovoltaic elements with a conversion contact without an intermediate layer or with a non-doped intermediate layer.

Claims

Patent claims 1. Organic electronic component (50) with a first electrode (2), a second electrode (9), and a layer system (20) arranged between the first electrode (2) and the second electrode (9) with at least a first photoactive layer (4) and a second photoactive layer (7), wherein a conversion contact (30) is arranged between the first photoactive layer (4) and the second photoactive layer (7), characterized in that the conversion contact (30) comprises layers arranged in the following order: a) a doped or undoped p-type layer (5) with an optical band gap of greater than 2.5 eV, wherein the p-type layer (5) has an ionization energy of greater than 5.0 eV;b) an n-doped intermediate layer (10) with a matrix material and at least one n-dopant, wherein the n-doped intermediate layer (10) has an electron affinity of greater than 4.4 eV, and wherein the proportion of the at least one n-dopant is 1 to 30 vol.%; and c) a doped n-type (6) layer with an electron transport material (ETM) and at least one n-dopant, wherein the n-type layer (6) has an electron affinity of less than 4.4 eV.

2. Organic electronic component (50) according to claim 1, wherein the p-type layer (5) has an ionization energy of greater than 5.2 eV, preferably greater than 5.4 eV, preferably from 5.2 eV to 5.6 eV.

3. Organic electronic component (50) according to claim 1 or 2, wherein the p-type (5) layer comprises a p-dopant with a LUMO more negative than -4.5 eV, preferably more negative than -4.7 eV.

4. Organic electronic component (50) according to one of the preceding claims, wherein the n-doped intermediate layer (10) has an electron affinity of greater than 4.5 eV, preferably greater than 4.7 eV, wherein the n-doped intermediate layer (10) preferably has a proportion of the matrix material of at most 98.5 vol.%, or preferably of at most 98 vol.%, and / or the matrix material of the n-doped intermediate layer (10) is selected from the group consisting of hexaazatriphenylene, preferably with six electron-withdrawing substituents, tetracyanobenzoquinone dimethane, tetracyanonaphtho chinon dimethyl ether, radialene, perylenetetracarboxylic dianhydride (PTCDA) and derivatives thereof.

5. Organic electronic component (50) according to one of the preceding claims, wherein the n-dopant of the n-doped intermediate layer (10) has a HOMO more negative than -4.6 eV, preferably more negative than -4.8 eV, and / or the proportion of the n-dopant in the n-doped intermediate layer (10) is 1 to 20 vol.%, preferably 2 to 20 vol.%.

6. Organic electronic component (50) according to one of the preceding claims, wherein the n-dopant of the n-doped intermediate layer (10) has an ionization energy of 4.8 to 5.2 eV, preferably of 5.0 to 5.2 eV, preferably the n-dopant of the n-doped intermediate layer (10) is selected from the group consisting of pentacene or derivatives thereof, TDATA or derivatives thereof, preferably m-MTDATA, TAD or derivatives thereof, preferably spiro-MeO-TAD, BPBPA or derivatives thereof, TNATA or derivatives thereof, preferably 2-TNATA, TPD or derivatives thereof, preferably MeO-TPD, and triarylamine derivatives having at least one alkyl or alkoxy substituent on at least two aryl substituents of the amine.

7. Organic electronic component (50) according to one of the preceding claims, wherein the n-type layer (6) in the conversion contact (30) of an organic photovoltaic element (OPV) has an electron affinity of less than 4.2 eV, preferably less than 4.0 eV, wherein the electron transport material of the n-type layer (6) is preferably selected from the group consisting of a fullerene and / or a fullerene derivative, preferably fullerene C60 or C70, NTCDA, and NTCDI or a derivative thereof, and / or the n-dopant of the n-type layer (6) has a HOMO more positive than -5.0 eV, preferably more positive than -4.8 eV.

8. Organic electronic component (50) according to one of the preceding claims, wherein the difference between the electron affinity of the n-doped intermediate layer (10) and the electron affinity of the n-type layer (6) is at least 0.5 eV, preferably at least 0.6 eV, or preferably at least 0.7 eV.

9. Organic electronic component according to one of the preceding claims, wherein the difference between the ionization energy of the p-type layer (5) and the electron affinity of the n-doped intermediate layer (10) is greater than 0.3 eV and less than 1.0 eV, preferably greater than 0.5 eV and less than 0.8 eV.

10. Organic electronic component (50) according to one of the preceding claims, wherein the n-doped intermediate layer (10) has a layer thickness of 2 nm to 100 nm, preferably of 5 nm to 50 nm, preferably of 5 nm to 30 nm, or preferably of 10 nm to 40 nm.

11. Organic electronic component (50) according to one of claims 1 to 10, wherein the n-doped intermediate layer (10) is arranged in direct contact with the p-type layer (5), and / or the n-doped intermediate layer (10) is arranged in direct contact with the n-type layer (6).

12. Organic electronic component (50) according to one of claims 1 to 11, wherein an intrinsic layer (11, 12) is arranged between the p-type layer (5) and the n-doped intermediate layer (10) and / or between the n-type layer (6) and the n-doped intermediate layer (10).

13. Organic electronic component (50) according to claim 12, wherein the intrinsic layer (11, 12) has a layer thickness of 1 nm to 10 nm, and / or the intrinsic layer (11, 12) between the n-type layer (6) and the n-doped intermediate layer (10) is formed from a bullerene and / or a fullerene derivative, preferably fullerene C60.

14. Organic electronic component (50) according to one of the preceding claims, wherein the first photoactive layer (4) and / or the second photoactive layer (7) comprise at least one donor and at least one acceptor forming a donor-acceptor system, wherein preferably the at least one donor is an ADA oligomer and / or a BODIPY, and preferably the at least one acceptor is an ADA oligomer and / or a fullerene and / or fullerene derivative.

15. Organic electronic component (50) according to one of the preceding claims, wherein the first electrode (2) and / or the second electrode (9) is in direct contact or in diffusion contact with an adhesive layer, preferably an adhesive layer of a protective layer or a barrier layer, preferably an adhesive layer based on acrylates, epoxy resins or silicones, or an oxide layer is arranged between the first electrode (2) and / or the second electrode (9) and the adhesive layer, wherein the oxide layer preferably has a layer thickness of at most 200 nm.

16. Organic electronic component (50) according to claim 15, wherein the organic electronic component (50) is an organic photovoltaic element, preferably an organic photovoltaic element encapsulated by polymer films, with the adhesive layer arranged between the polymer film and the first electrode (2) and / or the second electrode (9).

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