WO2014006566A1

WO2014006566A1 - Electrode arrangement for optoelectronic components

Info

Publication number: WO2014006566A1
Application number: PCT/IB2013/055426
Authority: WO
Inventors: Christian Uhrich; Toni MÜLLER; Rico Meerheim
Original assignee: Heliatek Gmbh
Priority date: 2012-07-02
Filing date: 2013-07-02
Publication date: 2014-01-09
Also published as: DE102012105812A1

Abstract

The invention relates to an optoelectronic component on a substrate (2), said component comprising a first (3) and a second (4) electrode, the first electrode being located on the substrate and the second electrode forming a counter-electrode. At least one photo-active layer system (5) is located between said electrodes, the layer system comprising at least one donor-acceptor system having organic materials.

Description

Electrode Arrangement for Optoelectronic Components The invention relates to a transparent electrode for optoelectronic components.

Optoelectronic components, such as solar cells or LEDs, TFTs, etc. are now widely used in everyday and industrial environments. Of particular interest in this case are those components which, due to their configuration, allow an arrangement on curved curved surfaces.

Thus, for example, thin-film solar cells are known, which have a flexible configuration and thus allow an arrangement on curved surfaces. Such

Solar cells preferably have active layers of amorphous silicon (-Si) or CIGS (Cu (In, Ga) (S, Se) ₂ ).

The disadvantage of these thin-film solar cells, which are mainly due to the materials high

Production costs.

Also known are organic light emitting diodes (OLEDs), which can be made very thin and therefore flexible due to the unnecessary backlight. Also known are solar cells with organic active layers, which are flexible

(Konarka - Power Plastic Series). The organic active layers can be composed of polymers (eg US7825326 B2) or small molecules (eg EP 2385556 A1). While polymers are characterized by the fact that they are not volatile and therefore only applied from solutions can, small molecules are vaporizable.

The advantage of such organic-based devices over conventional inorganic-based devices (semiconductors such as silicon, gallium arsenide) is the sometimes extremely high optical absorption coefficients

(Up to 2xl0 ⁵ cm ^-1 ), so that offers the opportunity to produce very thin solar cells with low material and energy consumption. Further technological aspects are the low cost, the possibility of producing flexible large-area components on plastic films, and the almost unlimited possibilities of variation and the unlimited availability of organic chemistry.

A solar cell converts light energy into electrical energy. The term photoactive also refers to the conversion of light energy into electrical energy. in the

In contrast to inorganic solar cells, solar cells do not directly generate free charge carriers by light, but excitons are first formed, ie electrically neutral excitation states (bound electron-hole pairs). Only in a second step, these excitons are separated into free charge carriers, which then contribute to the electric current flow.

One already suggested in the literature

Possible realization of an organic solar cell is a pin diode [Martin Pfeiffer, "Controlled doping of organic vacuum deposited dye layers: basics and applications", PhD thesis TU-Dresden, 1999.] with the following layer structure:

0. carrier, substrate, 1st ground contact, mostly transparent, 2nd p-layer (s),

3rd i-layer (s),

4th n-layer (s),

5. Deck contact. Here, n or p denotes an n- or p-type doping, which leads to an increase in the density of free electrons or holes in the thermal equilibrium state. However, it is also possible that the n-type layer (s) or p-type layer (s) are at least partially nominally undoped and only due to the material properties (e.g.

Mobilities), due to unknown impurities (e.g., residuals from the synthesis, disintegration or reaction products during film formation), or environmental influences (e.g., adjacent ones)

Layers, diffusion of metals or others

organic materials, gas doping from the

Ambient atmosphere) preferably n-conductive or preferably p-conductive properties. In this sense, such layers are primarily to be understood as transport layers. In contrast, the term i-layer designates a nominally undoped layer (intrinsic layer). One or more i-layers may in this case be layers of a material as well as a mixture of two materials (so-called interpenetrating networks or bulk heterojunction, M. Hiramoto et al., Mol., Cryst., Liq., Cryst., 2006, 444). pp. 33-40). The light incident through the transparent base contact generates excitons (bound electron-hole pairs) in the i-layer or in the n- / p-layer. These excitons can only be separated by very high electric fields or at suitable interfaces. Stand in Organic Solar Cells sufficiently high fields are not available, so that all promising concepts for organic solar cells based on the exciton separation at photoactive interfaces. The excitons pass through diffusion to such an active interface, where electrons and holes are separated. The material which the

Picking up electrons is doing as acceptor, and that

Material that receives the hole as a donor (or

Donor). The separating interface may be between the p (n) layer and the i-layer or between two i-layers. In the built-in electric field of

Solar cell, the electrons are now transported to the n-area and the holes to the p-area. Preferably, the transport layers are transparent or

largely transparent materials with a large band gap

(wide-gap) as described e.g. in WO 2004083958 are described. As wide-gap materials here are materials

denotes the absorption maximum in the wavelength range <450 nm, preferably at <400 nm. Since the excitons are always generated by the light and still no free charge carriers, the plays

Low-recombination diffusion of excitons to the active interface plays a critical role in organic solar cells. To make a contribution to the photocurrent, must therefore in a good organic solar cell the

Excess diffusion length significantly exceed the typical penetration depth of the light, so that the majority of the light can be used. Structurally and in terms of chemical purity, perfect organic crystals or

Thin films certainly fulfill this criterion. For large-area applications, however, the use of monocrystalline organic materials is not possible and the production of multiple layers with sufficient Structural perfection is still very difficult.

If the i-layer is a mixed layer, the task of absorbing light either takes on only one of the components or both. The advantage of mixed layers is that the generated excitons only travel a very short distance until they reach a domain boundary where they are separated. Of the

Removal of the electrons or holes is carried out separately in the respective materials. Because in the mixed layer the

Materials are in contact with each other everywhere, it is crucial in this concept that the separate charges have a long life on the respective material and from each location closed percolation paths for both types of charge to the respective contact

available.

From US 5,093,698 the doping is organic

Materials known. By admixture of an acceptor-like or donator-like dopant, the

Increased equilibrium charge carrier concentration in the layer and increased the conductivity. According to US 5,093,698, the doped layers are used as injection layers at the interface to the contact materials in

used electroluminescent devices. Similar doping approaches are analogous for solar cells

appropriate.

From the literature are different

Implementation options for the photoactive i-layer known. Thus, this may be a double layer (EP0000829) or a mixed layer (Hiramoto, Appl.

Phys.Lett. 58, 106e (1991)). Also known is a combination of double and mixed layers (Hiramoto, Appl. Lett., 58, 1062 (1991), US 6,559,375). Also known is that the mixing ratio in different areas of the mixed layer is different (US 20050110005) or the mixing ratio has a gradient.

Furthermore, tandem or multiple solar cells are known from the literature (Hiramoto, Chem. Lett., 1990, 327 (1990); DE 102004014046).

Organic literature has long been known from the literature

Tandemsolarzellen (Hiramoto, Chem. Lett., 1990, 327 (1990).) In the tandem cell of Hiramoto et al., There is a 2nm thick gold layer between the two single cells.The task of this gold layer is for a good electrical connection between the two single cells to ensure: the gold layer causes an efficient

Recombination of the holes from one subcell with the electrons from the other subcell and thus causes the two subcells are electrically connected in series. Furthermore, the gold layer absorbs like any thin layer

Metal layer (or metal cluster) part of the

incident light. This absorption is a loss mechanism in the tandem cell of Hiramoto

photoactive layers (H2Pc (metal-free phthalocyanine) / Me-PTC (N, N "-dimethylperylene-3, 4, 9, 10-bis (dicarboximide) in the two single cells of the tandem cell less light is available this tandem structure therefore purely on the electrical side.

Within this concept, the gold layer should be as thin as possible, or in the best case completely eliminated.

Organic pin tandem cells are also known from the literature (DE 102004014046): The structure of such a tandem cell consists of two single-pin cells, the layer sequence "pin" being the sequence of a p-doped one

Layer system, an undoped photoactive layer system and an n-doped layer system. The

doped layer systems are preferably made

transparent materials, so-called wide-gap

Materials / layers and they may also be partially or wholly undoped or location-dependent different doping concentrations or over a

have continuous gradients in the doping concentration. Specially also very low doped or

highly doped regions in the border region at the electrodes, in the border region to another doped or undoped

Transport layer, in the border region to the active layers or in tandem or multiple cells in the border region to the adjacent pin or nip-Teilzelle, i. in the recombination zone are possible. Also any

Combination of all these features is possible.

Of course, such a tandem cell may also be a so-called inverted structure (e.g., nip tandem cell)

Tandem cell implementation forms with the term pin tandem cells called. An advantage of such a pin tandem cell is that the use of doped transport layers makes a very simple and simple process

at the same time very efficient realization possibility for the recombination zone between the two sub-cells is possible. The tandem cell has e.g. a pin-pin structure on (or also possible, for example, nipnip). At the interface between the two pin sub-cells are each an n-doped layer and a p-doped layer, which form a pn system (or np system). In such a

doped pn system takes a very efficient

Recombination of electrons and holes. The stacking of two single pin cells results in a complete pin tandem cell without the need for additional layers. Especially advantageous here is that no thin Metal layers are more needed as in Hiramoto to ensure efficient recombination. As a result, the loss absorption of such thin metal layers can be completely avoided ... The top contacts previously described in the literature are not sufficient for the realization of optoelectronic devices with high transparency and have too high reflections. Furthermore, there is a high interest in the

Realization of transparent top contacts on opaque

Substrates.

For the realization of transparent top contacts

organic components are known from the literature thin thermally evaporated metal layers with intermediate layers and sputtered ITO layers. Bailey-Salzmann et al. show in their publication of 2006 (APPLIED PHYSICS LETTERS 88, 233502 _2006) the

Use of thin Ag layers (25nm) to realize semitransparent organic solar cells.

Meiss et al. show in their publication (APPLIED PHYSICS LETTERS 95, 213306 _2009) the use of

doped transport layers and thin Ag layers (14nm) for the realization of transparent organic solar cells. Moreover, in this publication, a thin Al intermediate layer under the Ag layer is used for smoothing the same. The use of organic layers on the thin Ag layer to increase the transparency of the top contact is also shown here.

In their 2011 release, Meiss et. al as an alternative to the previously described thin Al

Interlayer the use of a thin Ca layer. From the literature is also the realization of organic devices with transparent top contact on opaque

Basic contact known. Hoffmann et al. For example, in their publication of 2012 (APPLIED PHYSICS LETTERS 97, 253308, 2010), an organic light emitting diode (OLED) using doped transport layers, a thin Ag metal layer (13nm) and an organic layer on the Ag layer to increase transparency the top contact. The top contacts with thin metal layers previously described in the literature are all realized by means of thermal evaporation. Typical layer thicknesses of the thin metal layers are in the range of 13-15 nm. to

Realization of higher transparency of semitransparent organic components or increase of the efficiency of organic components on opaque substrate

transparent top contact, it is necessary to increase the transparency of the top contact by reducing the thickness of the thin metal contact. In the case of opaque substrates, the known solutions lead to increased parasitic absorption and reflection losses and thus to a reduction in efficiency compared to transparent substrates, such as with ITO ground contacts.

The object of the present invention is therefore to overcome the aforementioned disadvantages of the prior art and a transparent top contact for

specify optoelectronic components.

The object is achieved by a device according to the

Main claim solved. Advantageous embodiments are specified in the dependent claims.

According to the invention, an optoelectronic component a substrate which comprises a first and a second electrode, wherein the first electrode is arranged on the substrate and the second electrode a

At least one photoactive layer system is arranged between these electrodes, wherein between the counter electrode and the photoactive layer system at least one transport layer is arranged, characterized in that between the

Counter electrode and the at least one

Hole transport layer an electron transport layer is arranged.

In one embodiment of the invention, this includes

photoactive layer system a donor-acceptor system with organic materials.

In one embodiment of the invention, the

Electron transport layer at least one organic

Material.

In a further embodiment of the invention, the electron transport layer contains at least one fullerene.

In a further embodiment of the invention, the electron transport layer contains an inorganic material.

In a further embodiment of the invention, the electron transport layer has an n-type doping.

In a further embodiment of the invention, the counter electrode contains at least one layer which is arranged in the direction of the electron transport layer and comprises at least one metal.

In a further embodiment of the invention, the at least one layer of the counter electrode, which in

Direction of the electron transport layer is arranged Ag, Au, Pt, Cr, Ti, Al, Zr, Cu, Zn, Sn, Sr, La, In, Sc, Hf or alloys of at least one of the aforementioned elements.

Direction of the electron transport layer is disposed, a mixed layer, Ag, Au, Pt, Cr, Ti, Al, Zr, Cu, Zn, Sn, Sr, La, In, Sc, Hf or alloys and an alkali or alkaline earth metal, a metal oxide or an organic one

Material. In a further embodiment of the invention, the at least one layer of the counter electrode, which in

Direction of the electron transport layer is arranged, a mixed layer Ag and Ca.

In a further embodiment of the invention, an intermediate layer between the counter electrode and the

Electron transport layer arranged.

Electron transport layer arranged, wherein the

Interlayer an alkali or alkaline earth metal, a

Metal oxide or an organic material comprises.

Electron transport layer arranged, wherein the

Intermediate layer contains Ca.

Electron transport layer arranged, wherein the

Interlayer a layer thickness of 0.5nm to 5nm. Another embodiment of the invention is the Hole transport layer formed of an organic or inorganic material, wherein the

Hole transport layer is undoped or p-doped.

In a further embodiment of the invention, the optoelectronic component is an organic solar cell.

In one embodiment of the invention, the component has the following structure:

Electrode / donor-acceptor system / (p-doped) hole transport layer / (n-doped) electron transport layer / In one embodiment of the invention, the device has the following structure:

Electrode / (n-doped) electron transport layer / donor-acceptor system / (p-doped) hole transport layer / (n-doped) electron transport layer / counter electrode. Suitable materials for the electrode are selected from a group consisting of: ITO; Metal nanowire;

Metal layer; thin, transparent metal layer;

conductive polymer; conductive polymer with grid; DMD stack; Carbon nanotubes; Graph. Suitable donor materials are, for example:

Phthalocanine (ZnPc, CuPc, etc.); naphthalocyanine; Sub-naphthalocyanine; ADA oligothiophene; oligothiophene; DA-oligothiophene; Merocyanine.

Suitable acceptor materials include:

Fullerene derivative (C60; C70; PCBMC60; PCBMC70; ...), perylene derivative (PTCDA; MePTCDI; etc.); NTCDA (1,4,5,8-naphthalenetetracarboxylic dianhydride); PTCDA; NDCA; BPDCA The donor-acceptor system is a combination Donor and acceptor in the form of successive

Suitable materials of the electron transport layer are, for example: fullerene derivative (C ₆ o, C ₁₀ , PCBMC ₆ o, PCBMC70, etc.), perylene derivative (PTCDA, MePTCDI, etc.) and / or mixed layers. );

NTCDA (1,4,5,8-naphthalenetetracarboxylic dianhydride);

PTCDA; NDCA; BPDCA; ANQ.

Suitable materials of the hole transport layer are, for example:

NPB; DiNPB; BPAPF; Spiro-NPB; MeO-TPD; Mo0 ₂ . Suitable p-dopants are, for example: F4-TCNQ;

fluorinated fullerene (F36C60; F48C60).

Suitable n-dopants are, for example: AOB (acridine orange base); Ytterbium; Cr2 (hpp) 4; W2 (hpp) 4 (hpp =

1, 3, 4, 6, 7, 8-hexahydro-2H-pyrimido [1,2-a] pyrimidines).

In a further embodiment of the invention, the component consists of a combination of nip, ni, ip, pnip, pni, pip, nipn, nin, ipn, pnipn, pnin or pipn structures, in which a plurality of independent combinations comprising at least one i Layer are stacked on top of each other.

In a further embodiment of the invention that is

Substrate opaque executed.

In a further embodiment of the invention, the substrate is made transparent.

Opaque is not understood transparently within the meaning of the invention. In a further embodiment of the invention, the substrate is made flexible. Under a flexible substrate is in the sense of

present invention, a substrate understood, which is a deformability due to external force

guaranteed. As a result, such flexible substrates are suitable for mounting on curved surfaces. Flexible substrates are, for example, films or metal strips.

In a further embodiment of the invention, the electrode which is arranged on the substrate is made opaque.

In a further embodiment of the invention, the electrode is arranged on the substrate

transparent.

In a further embodiment of the invention, the electrode which is arranged on the substrate comprises a

Metal, metal alloy, metal oxide, metal grid, metal-metal oxide layer system, metal particles, metal nanowires, graphene or an organic semiconductor.

In a further embodiment of the invention, the active layer comprises at least one mixed layer having at least two main materials which form a photoactive donor-acceptor system. In a further embodiment of the invention

at least one main material is an organic material.

In a further embodiment of the invention is the organic material is small molecules. For the purposes of the invention, the term small molecules is understood to mean monomers which evaporate and thus on the

Substrate can be deposited. In a further embodiment of the invention, the organic material is at least partially polymers.

In a further embodiment of the invention, at least one of the active mixed layers comprises as acceptor a material from the group of fullerenes or

Fullerene derivatives.

In a further embodiment of the invention, at least one of the electrode and the counterelectrode is provided

doped, partially doped or undoped

Transport layer arranged.

In a further embodiment of the invention, a doped, partially doped or undoped one is present between the counterelectrode and the photoactive layer system

Transport layer is arranged. In a further embodiment of the invention, the component is at least somewhat

Light wavelength range semitransparent. Preferably, the device is colored in the human eye

appearing wavelength range semitransparent. Semitransparency is defined in the sense of the present

Invention understood a transparency <= 100% and> 1%.

In a further embodiment of the invention that is Optoelectronic component an organic light emitting diode.

In a further embodiment of the invention, the component is a pin single, pin tandem cell, pin multiple cell, nip single cell, nip tandem cell or nip multiple cell.

The invention also provides an electrode device comprising a layer system comprising at least one first

Layer of one metal or metal oxide, a second

Layer of a metal and a third layer of a cover layer, wherein the layer system has a transparency of 40 to 95%.

Furthermore, the invention also relates to the use of an electrode device in an optoelectronic component. In a further embodiment of the invention, the optoelectronic component has more than one photoactive layer between the electrode and the counterelectrode.

In an advantageous embodiment of the invention

The active layers of the component absorb as much light as possible. For this purpose, the spectral range in which the component absorbs light, designed as wide as possible.

In a further embodiment of the invention, the active layer system of the optoelectronic component consists of at least two mixed layers, which are direct

contiguous and at least one of the two Main materials of a mixed layer is an organic material other than the two main materials of another mixed layer. Each mixed layer consists of at least two main materials which form a photoactive donor-acceptor system. The donor-acceptor system is characterized in that, at least for the photoexcitation of the donor component, the excitons formed at the interface to the acceptor are preferably separated into a hole on the donor and an electron on the acceptor. When

Main material refers to a material ^¬ its volume or mass fraction in the layer is greater than 16%.

Other materials can be mixed for technical reasons or to adjust layer properties.

Already in the case of a double-mix layer, the component contains three or four different absorber materials, so that it can cover a spectral range of approximately 600 nm or approximately 800 nm.

In a further embodiment of the invention, the

Double mixed layer can also be used to achieve significantly higher photocurrents for a given spectral range by mixing materials that preferentially absorb in the same spectral range. This can then be used in the following to adjust the current in a tandem solar cell or multiple solar cell

to reach different subcells. Thus, in addition to the use of the cavity layer, a further possibility of adjusting the currents of the sub-cells is given.

In a further embodiment of the invention, to improve the charge carrier transport properties of the mixed layers, the mixing ratios in the

different mixed layers same or too

be different.

In a further embodiment of the invention, the Mixed layers preferably from two main materials.

In a further embodiment of the invention, a gradient of the

Mixing ratio be present. In a preferred embodiment of the invention, the optoelectronic component is designed as a tandem cell and it consists by the use of double or

Multiple mixed layers, the further advantage that the current equalization (current matching) between the sub-cells optimized by the choice of absorber materials in the mixed layers and thus the efficiency can be further increased.

In a further embodiment of the invention, the individual materials may be positioned in different maxima of the light distribution of the characteristic wavelengths which this material absorbs. For example, a material in a mixed layer in the second.

Maximum of its characteristic wavelength and the other material in the 3rd maximum. In a further embodiment of the invention, the optoelectronic component, in particular an organic solar cell, consists of an electrode and a counterelectrode and, between the electrodes, at least two organic active mixed layers, the mixed layers each being in the

consist essentially of two materials and the two main materials each form a mixed layer donor acceptor system and the two mixed layers directly adjacent to each other and at least one of the two main materials of a mixed layer another

Organic material is considered the two main materials of another mixed layer. In a development of the above-described embodiment, several or all of the main materials of the mixed layers are different from one another.

In a further embodiment of the invention, there are three or more mixed layers, which are arranged between the electrode and counter electrode.

In a further embodiment of the invention

in addition to the said mixed layers, further photoactive single or mixed layers are present. In a further embodiment of the invention is still between the mixed layer system and the one electrode

at least one more organic layer present.

In a further embodiment of the invention is still between the mixed layer system and the counter electrode

at least one more organic layer present.

In a further embodiment of the invention, one or more of the further organic layers are doped wide-gap layers, the maximum of the absorption being <450 nm. In a further embodiment of the invention, at least two main materials of the mixed layers

different optical absorption spectra.

In a further embodiment of the invention, the main materials of the mixed layers have different optical absorption spectra, which complement each other to cover the widest possible spectral range.

In a further embodiment of the invention, the absorption region extends at least one of

Main materials of the mixed layers in the infrared range. In a further embodiment of the invention, the absorption region extends at least one of

Main materials of the mixed layers in the infrared range in the wavelength range of> 700nm to 1500nm. In another embodiment of the invention, the HOMO and LUMO levels of the main materials are adjusted so that the system allows for maximum open circuit voltage, maximum short circuit current, and maximum fill factor. In a further embodiment of the invention, at least one of the photoactive mixed layers contains as acceptor a material from the group of fullerenes or

Fullerene derivatives (eo, C ₇ o, etc.).

In a further embodiment of the invention, all photoactive compound layers contain as an acceptor a material from the group of fullerenes or fullerene derivatives (C6o, C ₇ o, etc.).

In a further embodiment of the invention, at least one of the photoactive mixed layers contains as donor a material from the class of phthalocyanines,

Perylene derivatives, TPD derivatives, oligothiophenes or a

Material as described in WO2006092134.

In a further embodiment of the invention, at least one of the photoactive mixed layers contains as acceptor the material fullerene and as donor the material 4P-TPD.

In a further embodiment of the invention, the electrode consists of metal, a conductive oxide, in particular ITO, ZnO: Al or other TCOs or a conductive

Polymer, in particular PEDOT: PSS or PA I. Within the meaning of the invention, polymer solar cells which comprise two or more photoactive mixed layers are also included, the mixed layers being directly adjacent to one another. In the case of polymer solar cells, however, there is the problem that the materials are applied from solution and thus a further applied layer very easily causes the underlying layers to be dissolved, dissolved or changed in their morphology. In polymer solar cells, therefore, only a very limited multiple mixed layers can be produced and only by the fact that different material and solvent systems are used, which in the production of each other hardly or hardly

influence. Solar cells made of small molecules have a clear advantage in this case, since any systems and layers can be brought together in a vacuum by the vapor deposition process and thus the advantage of the

Multiple mixed layer structure can be used very widely and can be realized with any combination of materials.

In a further embodiment of the invention

Bauelementes is that between the first

electron-conducting layer (n-layer) and the electrode located on the substrate is still a p-doped layer, so that it is a pnip or pni structure, wherein preferably the doping is chosen so high that the direct pn Contact has no blocking effect, but it comes to low-loss recombination, preferably through a tunneling process.

In a further embodiment of the invention, a p-doped layer may be present in the device between the active layer and the electrode located on the substrate, so that it is a pip or pi structure, wherein the additional p-doped layer a Fermi level, which is at most 0.4 eV, but preferably less than 0.3 eV below the electron transport level of the i-layer, so that it is too low-loss

Electron extraction can come from the i-layer in this p-layer.

In a further embodiment of the invention, an n-layer system is still present between the p-doped layer and the counterelectrode, so that it is a nipn or ipn structure, wherein preferably the doping is chosen to be so high that the direct pn Contact none

blocking effect, but it has a lower loss

Recombination, preferably by a tunneling process.

In a further embodiment, an n-layer system between the intrinsic,

photoactive layer and the counterelectrode, so that it is a nin- or in-structure, wherein the additional n-doped layer has a Ferminiveaulage which is not more than 0.4 eV, but preferably less than 0.3 eV above the Lochertransportnivaus the i-layer is located, so that there may be lossy hole extraction from the i-layer in this n-layer.

Another embodiment of the invention

Component is that the device contains an n-layer system and / or a p-layer system, so that it is a pnipn, pnin, pipn or pin structure, which are characterized in all cases in that - regardless of Conduction type - the layer adjacent to the photoactive i-layer on the substrate side has a lower thermal work function than that of the substrate

remote from the i-layer adjacent layer, so that photogenerated electrons are preferably transported away to the substrate when no external voltage to the Component is created.

In a further embodiment of the invention, a plurality of conversion contacts are connected in series, so that e.g. is an npnipn, pnipnp, npnipnp, pnpnipnpn or pnpnpnipnpnpn structure.

In a preferred embodiment of the structures described above, these are designed as organic tandem solar cell or multiple solar cell. So it may be at the

Component to a tandem cell of a combination of nip, ni, ip, pnip, pni, pip, nipn, nin, ipn, pnipn, pnin or pipn structures act in which several independent combinations containing at least one i-layer, one above the other are stacked (cross combinations).

In another embodiment of the structures described above, this is a pnipnipn tandem cell

executed.

In a further embodiment, the acceptor material is at least partially in the mixed layer

crystalline form. In another embodiment, the donor material in the blend layer is at least partially in crystalline form.

In a further embodiment, both are

Acceptor material as well as the donor material in the

Mixed layer at least partially in crystalline form.

In a further embodiment, the acceptor material has an absorption maximum in the wavelength range> 450 nm. another embodiment has the donor Material over an absorption maximum in the wavelength range> 450nm.

In a further embodiment, the active contains

Layer system in addition to said mixed layer even more photoactive single or mixed layers.

In a further embodiment, the n-material system consists of one or more layers.

In another embodiment, the p-material system consists of one or more layers. In another embodiment, the n-

Material system one or more doped wide-gap

Layers. The term wide-gap layers defines layers with an absorption maximum in the

Wavelength range <450nm. In another embodiment, the p-

Material system one or more doped wide-gap

Layers .

In a further embodiment, the component between the first electron-conducting layer (n-layer) and the electrode located on the substrate contains a p-doped layer, so that it is a pnip or pni structure.

In a further embodiment, the device between the photoactive i-layer and the electrode located on the substrate contains a p-doped layer, so that it is a pip or pi structure, wherein the

additional p-doped layer has a Fermi level position which is at most 0.4 eV, but preferably less than 0.3 eV, below the electron transport level of the i-layer. In a further embodiment, the component contains an n-layer system between the p-doped layer and the counterelectrode, so that it is a nipn or ipn structure. In a further embodiment, the component contains an n-layer system between the photoactive i-layer and the counterelectrode, so that it is a n or in ^¬ structure, wherein the additional n-doped layer has a Ferminiveaulage which is at most 0, 4eV, but preferably less than 0.3eV is above the hole transport level of the i-layer.

In a further embodiment, the component contains an n-layer system and / or a p-layer system, so that it is a pnipn, pnin, pipn or p-i-n structure. In a further embodiment, the additional p-material system and / or the additional n-material system contains one or more doped wide-gap layers.

In a further embodiment, the component contains further n-layer systems and / or p-layer systems, such as e.g. is an npnipn, pnipnp, npnipnp, pnpnipnpn, or pnpnpnipnpnpn structure.

In another embodiment, one or more of the further p-material systems and / or the further n-material systems contains one or more doped wide-gap

Layers.

In a further embodiment, the device is a tandem cell of a combination of nip, ni, ip, pnip, pni, pip, nipn, nin, ipn, pnipn, pnin or pipn structures. In a further embodiment, the organic materials at least partially to polymers, but at least one photoactive i-layer is formed of small molecules.

In a further embodiment, the p-type material system contains a TPD derivative (triphenylamine dimer), a spiro compound such as spiropyrane, spiroxazine, MeO-TPD (Ν, Ν, Ν ', Ν'-tetrakis (4-methoxyphenyl) - benzidine), di-NPB

(Ν, Ν'-di (1-naphthyl) -N, N'-diphenyl- (1, 1'-biphenyl) 4, 4'-diamines), MTDATA (4, 4 ', 4 "-tris ( N-3-methylphenyl-N-phenyl-amino) -triphenylamine), TNATA

(4, 4 ', 4 "-tris [N- (1-naphthyl) -N-phenyl-amino] -triphenylamine), BPAPF (9,9-bis {4- [di- (p-biphenyl) -aminophenyl] } fluorenes), NPAPF (9,9-bis [4- (N, '-bisaphthalen-2-yl-amino) -phenyl] -9H-fluorenes), spiro-TAD

(2,2 ', 7,7'-tetrakis (diphenylamino) -9,9'-spirobifluorene), PV-TPD (N, N-di 4-2,2-diphenyl-ethen-1-yl-phenyl) N, -di 4-methylphenylphenylbenzidines), 4P-TPD (4,4'-bis- (N, N-diphenylamino) -tetraphenyl), or a p-type material described in DE102004014046. In another embodiment, the n-

Material system fullerenes, such as Οεο, C70; NTCDA (1,4,5,8-naphthalene-tetracarboxylic dianhydride), NTCDI (naphthalenetetracarboxylic diimide) or PTCDI (perylene-3,4,9,10-bis (dicarboximide) In another embodiment, the p-

Material system a p-dopant, said p-dopant F4-TCNQ, a p-dopant as in DE10338406, DE10347856,

DE10357044, DE102004010954, DE102006053320, DE102006054524 and DE102008051737 or a transition metal oxide (VO, WO, MoO, etc.).

In another embodiment, the n- Material system an n-dopant, said n-dopant is a TTF derivative (tetrathiafulvalene derivative) or DTT derivative (dithienothiophene), an n-dopant as described in DE10338406,

DE10347856, DE10357044, DE102004010954, DE102006053320, DE102006054524 and DE102008051737 or Cs, Li or Mg.

In another embodiment, an electrode

transparent with a transmission> 80% and the other electrode reflective with a reflection> 50%

executed.

In a further embodiment, the organic materials used have a low melting point, preferably <100 ° C, on.

In a further embodiment, the organic materials used have a low

Glass transition temperature, preferably <150 ° C, on.

In a further embodiment of the invention, by using light traps, the optical path of the incident light in the active system is increased. In a further embodiment of the invention, the component is designed as an organic pin solar cell or organic pin tandem solar cell. As a tandem solar cell while a solar cell is referred to, which consists of a vertical stack of two series-connected solar cells. In a further embodiment, the light trap is realized in that the component is constructed on a periodically microstructured substrate and the homogeneous function of the component, ie a short-circuit-free

Contacting and homogeneous distribution of the electrical

Field over the entire area, by using a doped wide-gap layer is ensured. Ultrathin components have an increased risk of forming local short circuits on structured substrates, such that ultimately the functionality of the entire component is jeopardized by such obvious inhomogeneity. This risk of short circuit is caused by the

Use of the doped transport layers reduced.

In a further embodiment of the invention, the light trap is realized in that the component is constructed on a periodically microstructured substrate and the homogeneous function of the component whose

Short-circuit-free contacting and a homogeneous distribution of the electric field over the entire surface is ensured by the use of a doped wide-gap layer. It is particularly advantageous that the light the

Passes absorber layer at least twice, which can lead to increased light absorption and thereby to improved efficiency of the solar cell. This can be achieved, for example, by the fact that the substrate

pyramid-like structures on the surface having heights and widths in the range of one to several hundred micrometers, respectively. Height and width can be chosen the same or different. Likewise, the pyramids can be constructed symmetrically or asymmetrically. In a further embodiment of the invention, the

Light trap realized by a doped wide-gap layer has a smooth interface with the i-layer and a rough interface to the reflective contact. The rough one

For example, interface can be defined by a periodic

Microstructuring can be achieved. Particularly advantageous is the rough interface when it reflects the light diffused, resulting in an extension of the light path within the photoactive layer.

In a further embodiment, the light trap is realized in that the component is built up on a periodically microstructured substrate and a

doped wide-gap layer a smooth interface with the i-layer and a rough interface to the reflective

Contact has.

In a further embodiment of the invention, the overall structure of the optoelectronic component is provided with transparent base and cover contact.

In a further embodiment, the

Optoelectronic components according to the invention in

Connection with energy buffer or energy storage medium such as batteries, capacitors, etc. used for connection to consumers or devices.

In a further embodiment, the

Optoelectronic components according to the invention in

Used in combination with thin film batteries.

In a further embodiment, the

Optoelectronic components according to the invention

curved surfaces, such as glass, concrete, tiles, clay, car glass, etc. used. It is advantageous that the organic

Solar cells versus conventional inorganic

Solar cells can be applied to flexible substrates such as films, textiles, etc.

For realizing the invention, the

above-described embodiments are combined with each other. The invention is based on some

Embodiments and figures will be explained in detail. The embodiments are intended to the invention

describe without limiting it. 1 shows a schematic representation of a first

inventive design of an electrode assembly, in

Fig. 2 is a schematic representation of a second

inventive design of an electrode assembly, in

3 shows the current-voltage curve of a component with a counter electrode according to the invention in comparison to an identical component with a non-inventive counter electrode and in

4 shows the current-voltage curve of a component with a further counter electrode according to the invention, wherein the

Dashed line indicates the dark curve and the solid line indicates the current-voltage curve under illumination.

In one embodiment of the invention, an optoelectronic component 1 according to the invention, such as a solar cell, is shown in FIG. The optoelectronic component 1 is arranged on a substrate 2 and comprises a first and a second electrode 3, 4, the first electrode 3, for example ITO, being arranged on the substrate 2 and the second electrode 4 being a counter electrode

for example, comprises Ag forms. Between these

Electrodes 3, 4, at least one photoactive layer system 5 is arranged. The photoactive layer system 5 comprises, for example, at least one donor-acceptor system with organic materials, such as ZnPc: C6o- Furthermore, between the counter electrode 4 and the photoactive

Layer system 5 at least one transport layer 6 is arranged. The transport layer 6, which, for example, as Hole transport layer is executed and it includes, for example, MeO-TPD: F4TCNQ. In addition, between the counter electrode 4 and the at least one

Transport layer 6, an electron transport layer. 7

arranged, which for example comprises C60: AOB.

In an alternative embodiment of the above-described embodiment is in Fig. 2 between the

Electrode 3, which is made for example of a nanowire wire mesh and the photoactive layer 5, which comprises about C60: ZnPc, a

Electron transport layer 8 is arranged. These

Electron-transport layer 8 comprises, for example, C60: AOB.

In a third embodiment, a sample is placed on glass once according to the invention with an ETL between the

Counter electrode and the HTL layer (3a), once for

Comparison without ETL between the counter electrode and the HTL layer (3b). The layer structure corresponds to a pnip single cell on a substrate with ITO electrode, im

Individuals like the following:

Substrate: Glass electrode: ITO - p-doped

Transport layer - n-doped transport layer - Absorber mixture layer: 1: 1 acceptor / donor - p-doped

Hole transport layer - 3a: n-doped

Electron transport layer - counter electrode: Ag.

FIG. 3 shows the current-voltage curve of the two samples 3a (solid line) and 3b (dashed line), which clearly show that device 3a according to the invention shows significantly higher performance and efficiency than

Comparative Example 3b. In a fourth exemplary embodiment, a component with the following layer structure is shown:

Substrate: Glass electrode: ITO - p-doped

Transport layer - absorber mixture layer: 1: 1 acceptor / donor - p-doped hole transport layer - n-doped

Electron transport layer: n-C60 - Interlayer: Ca - Counterelectrode: 1: 1 Ag / Ca - organic coupling layer.

In Fig. 4, the current-voltage curve can be seen. The most important characteristics are the filling factor of 69%, the open-circuit voltage of 0.83% and the short-circuit current of 5.6%, which indicate a well-functioning solar cell.

LIST OF REFERENCE NUMBERS

1 component

2 substrate

3 electrode arrangement

4 counter electrode

5 photoactive layer system

6-hole transport layer

7 electron transport layer

Claims

Electrode arrangement for optoelectronic components Claims

1. Optoelectronic component on a substrate

comprising a first and a second electrode, wherein the first electrode is arranged on the substrate and the second electrode forms a counterelectrode (4), wherein between these electrodes at least one

is arranged photoactive layer system, wherein

at least one hole transport layer (6) is arranged between the counter electrode (4) and the photoactive layer system, characterized in that an electron transport layer (7) is arranged between the counter electrode (4) and the at least one hole transport layer (6).

2. Optoelectronic component according to claim 1, characterized in that the photoactive layer system at least one donor acceptor system with organic

Materials includes.

3. Optoelectronic component according to one of claims 1 or 2, characterized in that the

Electron transport layer (7) contains at least one organic material.

4. Optoelectronic component according to one of claims 1 to 3, characterized in that the

Electron transport layer (7) contains at least one fullerene.

5. Optoelectronic component according to claim 1, characterized in that the electron transport layer (7) contains an inorganic material.

6. Optoelectronic component according to one of

preceding claims, characterized in that the electron transport layer (7) has an n-type doping.

7. Optoelectronic component according to one of

preceding claims, characterized in that the counter electrode (4) comprises at least one layer which is arranged in the direction of the electron transport layer (7) and contains at least one metal.

8. Optoelectronic component according to claim 7, characterized in that the layer Ag, Au, Pt, Cr, Ti, Al,

Zr, Cu, Zn, Sn, Sr, La, In, Sc, Hf or alloys comprises at least one of the aforementioned elements.

9. Optoelectronic component according to claim 7 or 8, characterized in that the layer is a

Is mixed layer containing Ag, Au, Pt, Cr, Ti, Al, Zr, Cu, Zn, Sn, Sr, La, In, Sc, Hf or alloys

at least one of the aforementioned elements and an alkali or alkaline earth metal, a metal oxide or an organic material.

10. Optoelectronic component according to claim 9, characterized in that the mixed layer contains Ag and Ca.

11. Optoelectronic component according to one of

preceding claims, characterized in that an intermediate layer between the counter electrode (4) and the electron transport layer (7) is arranged.

12. Optoelectronic component according to one of preceding claims, characterized in that an intermediate layer between the counter electrode (4) and the electron transport layer (7) is arranged, wherein the intermediate layer comprises an alkali or alkaline earth metal, a metal oxide or an organic material.

13. Optoelectronic component according to claim 12, characterized in that the intermediate layer contains Ca.

14. Optoelectronic component according to one of claims 11 to 13, characterized in that the

Intermediate layer has a layer thickness of 0.5 nm to 5 nm.

15. Optoelectronic component according to one of

preceding claims, characterized in that the hole transport layer (6) is formed of an organic or inorganic material, wherein the hole transport layer (6) is undoped or p-doped.

16. Optoelectronic component according to one of

previous claims, characterized in that the optoelektronsiche device an organic

Solar cell is.

17. Optoelectronic component according to one of

previous claims, characterized in that the device consists of a combination of nip, ni, ip, pnip, pni, pip, nipn, nin, ipn, pnipn, pnin or pipn structures, in which several independent

Combinations containing at least one i-layer stacked on top of each other.