KR20140007416A - Photovoltaic element - Google Patents

Abstract

A photovoltaic device 110, in particular a dye solar cell 112, for converting electromagnetic radiation into electrical energy is proposed. The photovoltaic device 110 includes at least one first electrode 116, at least one n-semiconductive metal oxide 120, at least one electromagnetic radiation-absorbing dye 122, at least one solid organic p-semiconductor. 126 and at least one second electrode 132. P-semiconductor 126 includes silver in oxidized form.

Description

Photovoltaic device {PHOTOVOLTAIC ELEMENT}

The present invention relates to a photovoltaic device, a process for producing a solid organic p-semiconductor for use in organic components, and a process for manufacturing a photovoltaic device. These photovoltaic devices and processes are used to convert electromagnetic radiation, in particular sunlight, into electrical energy. More specifically, the present invention can be applied to dye solar cells.

In solar cells the direct conversion of solar energy into electrical energy is called the "internal photo effect" of the semiconductor material, i.e. negative and positive charges at pn junctions or Schottky contacts. It is generally based on the generation of electron-hole pairs by separation of carriers and absorption of photons. In this way, a photovoltaic voltage is generated in the external circuit which can cause a photocurrent, through which the solar cell releases its power. Semiconductors can generally absorb only photons that have more energy than their bandgap. The size of the semiconductor bandgap thus determines the proportion of sunlight that can generally be converted to electrical energy.

Solar cells based on crystalline silicon were manufactured early in the 1950s. The technology at that time was supported by its use on space satellites. Although silicon-based solar cells dominate the global market today, the technology remains expensive. Thus, attempts are being made to develop new, less expensive approaches. Some of these approaches that form the basis of the present invention are outlined below.

M. et al., J.　Photochem. Photobio. C, 2003, 4, 145; Chiba et al., 일본 저널 Appl. Phys., 2006, 45, L638-L640 참조).An important approach to the development of new solar cells is organic solar cells, ie solar cells comprising at least one organic semiconductor material, or other materials, in particular organic dyes or even liquid electrolytes instead of solid inorganic semiconductors. And development of solar cells including semiconductors. A special case of innovative solar cells is the case of dye solar cells. Dye Solar Cells (DSC) are one of the most efficient alternative solar cell technologies to date. In the liquid modification of this technique, efficiencies of up to 11% are currently achieved (eg,

M. et al., J. Photochem. Photobio. C, 2003, 4, 145; Chiba et al., Japanese Journal Appl. Phys., 2006, 45, L638-L640).

Dye solar cells now in which some variations are present generally have two electrodes, at least one of which is transparent. According to their function, the two electrodes are referred to as "working electrode" (also "anode", generation of electrons) and "counter electrode" (also "cathode"). On or near the working electrode, an n-conductive metal oxide is generally applied, in particular a porous layer, for example a nanoporous layer, for example nanoporous titanium dioxide having a thickness of approximately 10-20 μm. (TiO ₂ ) layer was provided. It is also possible to provide at least one blocking layer, for example an impermeable layer of metal oxide (eg TiO ₂ ), between the layer of n-conductive metal oxide and the working electrode. n-conductive metal oxides generally have a light-sensitive dye added. For example, on the surface of an n-conductive metal oxide, a single layer of photosensitive dye (eg ruthenium complex) may be adsorbed, which can be converted into an excited state by absorption of light. On the counter electrode or on the counter electrode, a catalyst layer (for example platinum) of several micrometers in thickness is often present. The area between two electrodes in a conventional dye solar cell is generally filled with a solution of redox electrolyte, for example iodine (I ₂ ) and / or potassium iodide (KI).

The function of the dye solar cell is based on the absorption of light by the dye. From the excited light, electrons are transported to the n-semiconducting metal oxide semiconductor and to the anode thereon, while the electrolyte ensures charge balance through the cathode. n-semiconductive metal oxides, dyes and electrolytes are thus essential components of dye solar cells.

However, dye solar cells made from liquid electrolytes have in many cases non-optimal seals, which can cause stability problems. Liquid redox electrolytes can in particular be replaced by solid p-semiconductors. Such solid dye solar cells are also referred to as sDSCs (solid DSCs). The efficiency of solid modifications of dye solar cells is currently approximately 4.6-4.7% (Snaith, H., Angew. Chem. Int. Ed., 2005, 44, 6413-6417).

Various inorganic p-semiconductors such as CuI, CuBr · 3 (S (C ₄ H ₉ ) ₂ ) or CuSCN have been used in place of redox electrolytes in dye solar cells to date. For example, it is also possible to apply the results from photosynthesis. Even in nature, it is the Cu (I) enzyme plastocyanin which, in photosystem I, reduces the oxidized chlorophyll dimer again. Such p-semiconductors can be processed by at least three different methods (ie: from solution, by electrodeposition, or by laser deposition).

Organic polymers are also already used as solid p-semiconductors. Examples include polypyrrole, poly (3,4-ethylenedioxythiophene), carbazole-based polymers, polyaniline, poly (4-undecyl-2,2'-bithiophene), poly (3-octylthiophene), Poly (triphenyl-diamine) and poly (N-vinylcarbazole). In the case of poly (N-vinylcarbazole), the efficiencies are increased by 2%. In situ polymerized PEDOT (poly (3,4-ethylenedioxythiophene)) also showed an efficiency of 0.53%. The polymers described herein are usually not used in pure form but with additives.

Inorganic-organic mixing systems are also already used in place of redox electrolytes in dye solar cells. For example, CuI was used in combination with PEDOT: PSS as the hole conductor in sDSC (Zhang J. Photochem: Photobio., 2007, 189, 329).

et al., Appl. Phys. Lett., 2001, 79, 2085 참조). TiO₂ 층의 더 양호한 피복을 달성하고 그리고 스피로-MeOTAD 에 대한 양호한 젖음성을 가지는 염료들은 4% 초과의 효율들을 나타낸다. 루테늄 복합체가 옥시에틸렌 측사슬들을 구비한 경우 휠씬 더 양호한 효율들 (대략 4.6%) 이 보고되었다.It is also possible to use low molecular weight organic p-semiconductors, ie unpolymerized organic p-semiconductors, for example monomeric or else oligomeric, organic p-semiconductors. The first use of low molecular weight p-semiconductors in solid dye solar cells replaced the liquid electrolyte with a vapor-deposition layer of triphenylamine (TPD). Use of organic compound 2,2 ', 7,7'-tetrakis (N, N-di-p-methoxyphenylamine) -9,9'-spirobifluorene (spiro-MeOTAD) in dye solar cells Was reported in 1998. It can be introduced from solution and has a relatively high glass transition temperature which prevents poor contact with the dye and unwanted crystallization. Methoxy groups regulate the oxidation potential of Spiro-MeOTAD so that the Ru complex can be efficiently regenerated. For Spiro-MeOTAD alone as a p-semiconductor, a maximum IPCE (incident photon to current conversion efficiency, external photon conversion efficiency) of 5% was found. When N (PhBr) ₃ SbCl ₆ , and Li [CF ₃ SO ₂ ) ₂ N as dopant were also used, the IPCE rose to 33% and the efficiency was 0.74%. The use of tert-butylpyridine as a solid p-semiconductor increases the efficiency to 2.56%, resulting in an open circuit voltage (V _oc ) of approximately 910 mV and an short circuit current of approximately 5 mA (I _SC ) in an active region of approximately 1.07 cm ² . Have ()

et al., Appl. Phys. Lett., 2001, 79, 2085). Dyes that achieve better coverage of the TiO ₂ layer and have good wettability to Spiro-MeOTAD show efficiencies above 4%. Even better efficiencies (approximately 4.6%) have been reported when the ruthenium complex is equipped with oxyethylene side chains.

L. Schmidt-Mende et al ., Adv. Mater. 17, p. 813-815 (2005) proposes indolin dyes for dye solar cells with spirobifluorenes as amorphous organic p-conductors. This organic dye, having an absorption coefficient four times higher than the ruthenium composite, exhibits high efficiency (4.1% in one aspect) in solid dye solar cells. In addition, a concept has been proposed in which polymerizable p-semiconductors are directly bonded to Ru dyes (Peter, K., Appl. Phys. A. 2004, 79, 65). Durrant et al . Adv. Munc. Mater. In 2006, 16, 1832-1838 it is described that in many cases the photocurrent directly depends on the yield in the hole transition from the oxidized dye to the solid p-conductor. This depends on two factors: firstly the penetration of the p-semiconductor into the oxide pores and secondly the thermodynamic driving force for charge transfer (ie in particular the difference in free enthalpy ΔG between the dye and the p-conductor). Depends on

One problem with dye solar cells is that the proportion of light that can be used by the dye is generally limited by the energy distance between the Fermi energies of the n- and p-conductors used. Photovoltage is also generally limited by this distance. In addition, the utilization of incident light is generally not optimal since dye solar cells generally have to be relatively thin due to the required charge transport (eg 1-2.5 micrometers).

The prior art discloses that the addition of silver nitrate (AgNO ₃ ) to dye solutions can lead to an increase in solar cell efficiency (J. Krueger, Thesis, EPFL Lausanne, 2003 (Thesis No. 2793), p. 76 -100). The general use of silver in oxidized form as dopant for p-semiconductors is not described.

The electrical and photoelectric properties of dye solar cells with different low molecular weight p-semiconductors have been reviewed in various further studies. An example can be found in U. Bach, thesis, EPFL Lausanne, 2000 (Thesis No. 2187), and especially there on pages 139-149. One feature discussed here is the very low conductivity of Spiro-MeOTAD. For example, in films with a layer thickness of approximately 2 micrometers, resistivities [MΩ / cm ² ] were measured. Conductivity (κ) is

Lt; / RTI >

In this equation, e = 1.6022 x 10 ^-19 C and is the basic charge of electrons or holes. μ represents the charge carrier mobility and N _h is the charge density of the holes in this case. Assuming that mobility does not change, in the case of p-materials, ie in the case of p-doping, the conductivity rises as a result of the addition of additional holes. The result of this is that the fill factors of sDSCs are not very high, especially at low light intensities. Fill rates in photovoltaics generally refer to the product of the open circuit voltage and the short circuit current and the quotient of the solar cell's maximum power at the point of maximum power. In the current-voltage diagram, the filling factor can often be described as the area ratio of the largest rectangle below the current-voltage curve to the smallest rectangle surrounding the current-voltage curve. Fill rate is dimensionless. Low fill rates generally indicate that some of the power generated is being lost due to the internal resistance of the cell. In the above-described case of Spiro-MeOTAD, relatively low filling rates are thus described, for example, by F. Fabregat-Santiago et. al ., J. Am. Chem. As also described in Soc., 2009, 131 (2), 558-562, this is explained by the high resistivity of Spiro-MeOTAD, especially in illumination of one sun.

The prior art also discloses doping of low molecular weight organic p-semiconductors. See, eg, U.'Bach, thesis, EPFL Lansanne, 2000 (Thesis No. # 2187), p. At 37-50, antimony salts are used as dopants for Spiro-MeOTAD. Doping operations can be described chemically as follows:

Spiro compounds had a ratio of 0.17-0.18 mM and a concentration of 0.26-0.33 mM Sb was used. Even if the conductivity increased, hole mobility decreased as a result of the addition of negative ions, which worsened the charge transport. In addition, the stability of these antimony salts in the cells has been questioned.

In N. Rossier-Iten, thesis, EPFL Lausanne, 2006 (Thesis No. 3457), in particular p. 56-75 and p. In 91-113, various doped hole conductor materials have also been reviewed. The dopants used there for amorphous hole conductors in sDSCs are I ₂ , 2,3-dichloro-5,6-dicyano-1,4-benzoquinone, NOBF ₄ , and also doped spirodiral cations (Spiro-MeOTAD ⁺⁺ [PF _6- ] ₂ ) (0.1-0.7%). However, no definite improvement in sDSC cells was achieved.

Snaith et al ., Appl. Phys. Lett. In 2006, 89, 262114-262116, it was found that the mobility of holes in sDSCs was greatly improved by the addition of lithium bis (trifluoromethylsulfonyl) amine (Li-TFSI). Thus, no oxidation of Spiro-MeOTAD is observed here, ie there is no actual doping effect, but it was possible to increase the mobility from 1.6 × 10 ⁻⁴ cm ² / Vs to 1.6 × 10 ⁻³ cm ² / Vs. Since the anions act as what is called coulomb traps (charge carrier traps), the conductivity of spiro-MeOTAD is less affected by antimony salt, and the best sDSC cells are found to be achieved even without these salts. It became.

Usually, an amount greater than 1 μmol% of the dopant is required to improve the charge mobility of the amorphous p-conductor.

Organic p-dopants, such as F4-TCNQ (tetrafluorotetracyanoquinomimethane), have also already been used in p type organic polymers (eg R. Friend et al ., Adv. Mater ., 2008, 20, 3319-3324, Zhang et al ., Adv. Funct. Mater., 2009, 19, 1901-1905). Also called protic doping of polythiophenes with alkylsilanes has been reported (Podzorov et. al ., Advanced Functional Materials 2009, 19, 1906-1911). However, components with organic dopants have a relatively low life in many cases.

In addition, SnCl ₅ and FeCl ₃ are also known to be usable as p-dopants. In addition, polymers, such as PEDOT, doped with LiCF ₃ SO ₃ , LiBF ₄ , LiTFSI and LiClO ₄ , have also been used as hole conductors in sDSCs, for example. However, even for these components, relatively low external power efficiencies of up to 2.85% have been reported (Yanagida et. al ., JACS, 2008, 130, 1258-1263).

In addition, the use of metal oxides as dopants is also known from the prior art, for example from DE 10 2007 024 153 A1 or DE 10 2007 023 876 A1. Metal oxides are deposited on the organic layers, where they serve as dopants. Examples mentioned are examples of phenanthroline derivatives as, for example, complex-forming matrix materials doped with rhenium oxide.

In addition, studies on the doping of organic p-transport materials for organic light emitting diodes with vapor deposited inorganic compounds are also described, for example, by Kim et. al ., Appl. Phys. Lett. 2007, 91, 011113 (1-3). Here, for example, NPB was doped with ReO ₃ (8-25%), which resulted in lower use voltages (turn-on voltages) and higher power efficiencies. The stability of OLEDs is likewise improved. Kim et al ., Org. Elec. In 2008, 805-808, the hole injection layers were doped with CuI. Such doping also resulted in higher current efficiencies and energy efficiencies. Kim et al ., Appl. Phys. Lett. In 2009, 94, 123306 (1-3), CuI, MoO ₃ and ReO ₃ are compared as dopants for organic light emitting diodes (OLEDs). Here, a trend is found that the energy difference between the Fermi level of the dopants and the highest occupied molecular orbital (HOMO) of the organic p-semiconductor plays an important role. Overall, it has been found that dopants increase charge carrier densities and thus increase conductivity in transport layers, making them equivalent to p-doping.

Kahn et al ., Chem. Mater. 2010, 22, 524-531 also discloses that molybdenum dithiene (Mo (tfd) ₃ ) at concentrations from 0 to 3.8 mol% can dope various hole conductors. UPS experiments (UV photoelectron spectroscopy) showed that the Fermi level of the hole conductor is shifted in the direction of HOMO, an indication of p-doping.

Kowalsky et al ., Org. Elec. In 2009, 10, 932-938 it is reported that Mo ₃ O ₉ clusters of vapor deposited MoO ₃ may possibly occur and play any role in doping. In addition, the Fermi level (6.86 eV) and electron affinity (6.7 eV) were measured at the much lower levels assumed previously. It was also speculated that MoO ₃ layers could be easily n-doped by oxygen defective sites, resulting in improved alignment of the bands with respect to each other (Kanai et. al ., Organic Electronics 2010, 11, 188-194).

In order to improve hole injection into the electrode or hole extraction from the electrode, the use of pure layers of metal oxides (eg MoO ₃ and V ₂ O ₅ ) is also described for OLEDs and for organic solar cells. It is. For example, Y. Yang et al ., Appl. Phys. Lett. 2006, 88, in the 073 508, as an intermediate layer between the ITO (Indium Tin Oxide) and p- type polymer V ₂ O _5, MoO _3, and PEDOT: PSS can be used in the review. Even in what are called inverted polymer cells, where the holes must migrate from the p-type polymer to the cathode (generally Ag in this case), the VOx layer is also vapor deposited between the polymer and silver, resulting in cell characteristics. Cause an improvement in

In addition, the production of metal oxide buffer layers from aqueous solutions is also known. See, for example, Liu SESMC, 2010, 842-845, vol. In 94, MoO ₃ layers are described as successfully used as buffer layers on the anodes in polymer solar cells. These layers were also used as part of the charge recombination layer in what are called organic tandem solar cells (eg, Kowalsky et. al ., Adv. Func. Mater. 2010, 20, 1762-1766).

In the past few years, dye solar cells have actually been preserved under air (ambient conditions) in many cases, since no p-dopant that is efficient, soluble and stable for hole transport materials is generally known yet. In the process, oxygen penetrating into the sDSCs dops the sDSC. However, the preservation of the cells in the ambient atmosphere or in a controlled O ₂ atmosphere is not well regenerated and is relatively problematic with regard to the commercial production of solar modules. In addition, it is impossible to encapsulate oxygen-doped cells in a hermetic manner since the high conductivity overall conductors required for operation are only guaranteed by constant contact with oxygen.

It is therefore an object of the present invention to provide a photovoltaic device and a process for manufacturing a photovoltaic device which at least considerably avoid the problems of known photovoltaic devices and their fabrication processes. More specifically, stable p-dopants and doping ps, which are specific for photovoltaic devices with p-semiconductors with high conductivity and also exclude oxygen, result in stable p-doping of organic materials for dye solar cells. Specify the process of the semiconductors. At the same time, dye solar cells, which have high quantum efficiency and high filling rate and are stable even in the encapsulated state, will be desirable.

This object is achieved by the invention with the features of the independent claims. Advantageous developments which can be implemented individually or in any combination are described in the dependent claims.

In a first aspect of the invention, a photovoltaic device, in particular a dye solar cell, for converting electromagnetic radiation into electrical energy is proposed. The photovoltaic device comprises at least one first electrode, at least one n-semiconductive metal oxide, at least one dye absorbing electromagnetic radiation, at least one solid organic p-semiconductor and at least one second electrode, preferably Include (but not necessarily) in the order described or in reverse order, and the p-semiconductor comprises silver in oxidized form.

The p-semiconductor may be or may be prepared in particular by providing at least one p-semiconductive organic material 128 and an oxidized form of silver to the at least one carrier element, wherein the oxidized form of silver at least one of the carrier elements is (I) salt _{^{[Ag +] m [a m}} -] preferably provided in the form of and, a ^{m -} is an organic or an anion of an inorganic acid and m is an integer in the range of 1 to 3 And preferably m is 1.

[A ^{m −} ] may in particular be an anion of an organic acid, and preferably the organic acid has at least one fluorine group (—F) or cyano group. In this case, [A ^{m -]} has the following structure and more preferably formula (II).

R ^a is a fluorine group (-F), or an alkyl radical, a cycloalkyl radical, an aryl radical or a heteroaryl radical, each substituted by a fluorine group or a cyano group,

X is -O ^- or -N ^-- R ^b ,

R ^b contains a fluorine group (-F) or a cyano group,

R ^b further includes a group of the formula —S (O) ₂ —.

R ^a may in particular be selected from the group consisting of —F, —CF ₃ , —CF ₂ —CF _3, and —CH ₂ —CN.

X may in particular be -N ^-- R ^b , and R ^b is in particular -S (O) ₂ -F, -S (O) ₂ -CF ₃ , -S (O) ₂ -CF ₂ -CF ₃ and- It may be selected from the group consisting of S (O) ₂ -CH ₂ -CN.

[A ^{m −} ] is in particular bis (trifluoromethylsulfonyl) imide (TFSI ⁻ ), bis (trifluoroethylsulfonyl) imide, bis (fluorosulfonyl) imide and trifluoromethylsulfo It may be selected from the group consisting of nates.

Preferably, [A ^{m −} ] is bis (trifluoromethylsulfonyl) imide (TFSI ⁻ ).

In an alternative preferred embodiment, [A ^{m −} ] is a trifluoroacetate group.

In addition, [A ^{m −} ] may in particular also be a NO ₃ ⁻ group.

The application can be carried out by any desired process. It is desirable in the context of the present invention to provide at least one p-conductive organic material 128 and silver by deposition from the liquid phase.

The p-semiconductor provides at least one carrier element with at least one p-conductive organic material 128 and at least silver, preferably at least one silver (I) salt [Ag ⁺ ] _m [A ^{m −} ] Produced or produced by means of which the provision is carried out by film formation from a liquid phase comprising at least one p-conductive organic material and at least one silver (I) salt [Ag ⁺ ] _m [A ^{m −} ].

Deposition can also be carried out in principle by any desired deposition process, for example by spin-coating, knife-coating, printing or combinations of the deposition processes and / or other deposition processes.

The p-semiconductor may in particular comprise at least one organic matrix material, in which case the anionic compounds [A ^{m −} ] and Ag ⁺ are mixed into the matrix material or present in the matrix material, in particular in dissolved form exist.

At least Ag ⁺ and preferably also anionic compounds [A ^{m −} ] may be present in an essentially homogeneous distribution in the matrix material.

The matrix material may in particular comprise at least one low molecular weight organic p-semiconductor.

The low molecular weight organic p-semiconductor may in particular comprise at least one spiro compound.

Low molecular weight organic p-semiconductors include, in particular, spiro compounds, in particular spiro-MeOTAD; It may be selected from compounds having the following structural formula.

here

A ¹ , A ² and A ³ are each independently, optionally substituted aryl groups or heteroaryl groups,

R ¹ , R ² and R ³ are each independently selected from the group consisting of substituents -R, -OR, -NR ₂ , -A ⁴ -OR and -A ⁴ -NR ₂ ,

R is selected from the group consisting of alkyl, aryl and heteroaryl,

A ⁴ is an aryl group or heteroaryl group,

In each case in formula (I) n is independently a value of 0, 1, 2 or 3,

Provided that the sum of the individual n values is at least 2 and at least two of the R ¹ , R ² and R ³ radicals are —OR and / or —NR ₂ .

Preferably, A ² and A ³ are the same; Therefore, the compound of formula (I) preferably has the following structure (Ia).

The photovoltaic device may further comprise at least one encapsulation, which is designed to shield the photovoltaic device, in particular the electrodes and / or p-semiconductor, from the ambient atmosphere.

In a preferred embodiment, the p-semiconductor is provided by providing at least one p-conductive organic material 128 and at least one silver (I) salt [Ag ⁺ ] _m [A ^{m −} ] to the at least one carrier element. Preparable or prepared, the provision may be effected by deposition from a liquid phase comprising at least one p-conductive organic material and at least one silver (I) salt [Ag ⁺ ] _m [A ^{m −} ], The liquid phase comprises at least one silver (I) salt [Ag ⁺ ] _m [A ^{m −} ] at a concentration of 0.5 mM / ml to 50 mM / ml, more preferably 1 mM / ml to 20 mM / ml Include in concentration.

In another aspect of the invention, a process for producing a solid organic p-semiconductor for use in an organic component, in particular in a photovoltaic device according to one or more of the above-described or described embodiments of the photovoltaic device according to the invention. Is proposed. In this process, in the form of at least one of the p- conductive organic matrix material and at least the oxidation is preferably at least one of silver (I) salt _{^{[Ag +] m [A m}} -] is at least one liquid phase from at least one of is provided on the carrier element, [a] ^- is an anion of an organic or inorganic acid, compound _{^{[Ag +] m [a m}} -] is preferably AgNO _3, or is (methylsulfonyl-trifluoromethyl) bis imide.

The liquid phase comprises at least one solvent, in particular an organic solvent, in particular cyclohexanone; Chlorobenzene; Benzofuran; And it may further comprise a solvent selected from the group consisting of cyclopentanone.

This process can be carried out at least partly, especially in a low oxygen atmosphere, for example less than 500 ppm ppm, in particular less than 100 ppm ppm, more preferably less than 50 ppm ppm, or even more preferably less than 10 ppm ppm It may be performed at least partially in an atmosphere containing oxygen of.

In another aspect of the present invention, a process for manufacturing a photovoltaic device, in particular a photovoltaic device according to one or more of the configurations of the photovoltaic device according to the invention described above or hereafter, is proposed. In this process, at least one first electrode, at least one n-semiconductive metal oxide, at least one dye absorbing electromagnetic radiation, at least one solid organic p-semiconductor and at least one second electrode, in particular ( But not necessarily), in the order described or in reverse order, the p-semiconductor is prepared according to one or more of the configurations of the process according to the invention for the preparation of the solid organic p-semiconductor described above or hereafter described. Manufactured by the process.

In the context of the present invention, it has surprisingly been found that oxidized forms of silver can achieve efficient p-doping, especially in dye solar cells. Especially effective is p- doped especially formula _{^{[Ag +] m [A m}} -] of silver (I) can be accomplished using a salt thereof, [A ^{m -]} is an anion of an organic or inorganic acid and m is from 1 to 3 An integer in the range. These silver (I) salts may in particular be provided in the liquid phase by one or more organic solvents, preferably with the p-semiconductive matrix material and optionally with one or more organic salts. In this way, it is possible to achieve photovoltaic devices with high fill rates and high long term stability.

In the above-mentioned first aspect of the present invention, a photovoltaic element for converting electromagnetic radiation into electrical energy is thus proposed. The photovoltaic device may in particular comprise one or more photovoltaic cells. The photovoltaic device may in particular comprise at least one layer structure, which may for example be provided on a substrate. The photovoltaic device may in particular comprise at least one dye solar cell and / or may be configured as a dye solar cell.

The photovoltaic device comprises at least one first electrode, at least one n-semiconductive metal oxide, at least one electromagnetic radiation-absorbing dye, at least one solid organic p-semiconductor and at least one second electrode. It is proposed that the p-semiconductor comprises silver in oxidized form.

The described elements may be provided in particular in the order described. For example, a photovoltaic device may comprise at least one first electrode, at least one n-semiconductive metal oxide, at least one electromagnetic radiation-absorbing dye, at least one solid organic p-semiconductor and at least one second electrode. May be included in the order described. However, as is common in dye solar cells, the dye and n-semiconductive metal oxide may also be combined completely or partially. For example, the n-semiconductive metal oxide may be impregnated completely or partially with at least one dye, or may be mixed with this dye in some other way. In this way and / or in some other way, the n-semiconducting metal oxide can in particular be sensitized with a dye, for example the dye molecules can be provided as a single layer for particles of the n-semiconducting metal oxide. have. For example, there may be a direct contact between the dye molecules and the n-semiconductive metal oxide, allowing for the transport of charge carriers. The photovoltaic device may comprise at least one layer of n-semiconducting metal oxide, at least one layer of solid organic p-semiconductor, in particular, optionally with a dye. This layer structure may be embedded between the electrodes. The photovoltaic device may also include one or more additional layers. For example, one or more additional layers, for example one or more buffer layers, for example layers of metal oxide, may be introduced between the first electrode and the n-semiconductive metal oxide. The buffer layer is preferably impermeable, but the n-semiconductive metal oxide may in particular be porous and / or particulate. In particular, as described in detail below, the n-semiconductive metal oxide may be configured as a nanoparticle layer. In addition, it is also possible for one or more additional layers to be provided between the n-semiconducting metal oxide and the solid organic p-semiconductor and also optionally for one or more additional layers to be provided between the p-semiconductor and the second electrode. Do.

p- semiconductor, in particular, in an oxidized form, and preferably formula _{^{[Ag +] m [A m}} -] is at least one p- may be doped with salts (I) of the. This, by the oxidized form is preferably formula [Ag ^+] _m ^- wherein at least one of the p- conductivity characteristics of the p- semiconductor by (I) salt is obtained, or that the improvement in [A ^m] it means. More specifically, in the oxidized form, in particular formula _{^{[Ag +] m [A m}} -] of at least one of silver (I) salts, p- doped semiconductor or to the matrix material present in the p- semiconductor It may be set. For example, p- semiconductor is at least one and may comprise the organic matrix material, in the oxidized form in this case is preferably a formula _{^{[Ag +] m [A m}} -] at least one of silver (I of ) Salts are mixed into the matrix material. This is of the oxidized form, and preferably formula _{^{[Ag +] m [A m}} -] at least one of is preferably achieved by providing both the (I) salt, and the organic matrix material on at least one carrier material .

Accordingly, the present invention preferably relates to the photovoltaic device described above, wherein the p-semiconductor is preparable by providing at least one p-conductive organic material 128 and oxidized form of silver to at least one carrier element or was prepared, at least on silver, at least one carrier element of the oxidized form of a silver (I) salt [Ag ^+] _m of an organic or inorganic acid ^- [a ^{m -]} is preferred, and a ^m is provided in the form of It is an anion and m is an integer in the range of 1-3, Preferably m is 1.

The matrix material and silver can be provided together or in separate steps in the carrier material. Preferably, the matrix material and silver are provided together in the carrier material. "Provide together" or "provide together" in this context means that the mixture G, preferably comprising both of the matrix materials, is provided to the carrier material in at least one step, preferably in one step.

Preferably, the mixture G is in liquid phase. The term "liquid phase" in this context means that the mixture G is at least partly present as a liquid. Preferably, the mixture G or preferably the liquid phase comprises silver and at least one solvent in which at least one organic matrix material is dissolved and / or dispersed, as described below. As mentioned above, the provision is preferably carried out by deposition from the liquid phase, and the deposition is also carried out in principle by any preferred deposition process, for example spin-coating, knife-coating, printing or the above deposition processes. And / or combinations of other deposition processes.

Low molecular weight  Organic p-semiconductor:

In particular, the matrix material may have at least one low molecular weight organic p-semiconductor. Low molecular weight materials are generally understood to mean materials which are present in monomeric, non-polymerized or non-oligomeric form. The term "low molecular weight" as used in this context means that the semiconductor preferably has a molecular weight within the range of 100 to 25000 g / mol. Preferably, low molecular weight materials have molecular weights of 500 to 2000 g / mol. These low molecular weight organic p-semiconductors may form the matrix material described above in particular, and may uniquely have p-semiconductor properties. In general, in the context of the present invention, p-semiconductor properties are understood to mean the properties of materials, in particular organic molecules, which form holes, transport these holes and transfer them to adjacent molecules. In particular, stable oxidation of these molecules should be possible. In addition, the low molecular weight organic p-semiconductors mentioned may in particular have extensive π-electron systems. In particular, at least one low molecular weight p-semiconductor may be processable from solution. The low molecular weight p-semiconductor may in particular comprise at least one triphenylamine. It is particularly preferred that the low molecular weight organic p-semiconductor comprises at least one spiro compound. Spiro compounds are understood to mean polycyclic organic compounds in which the rings are connected to only one atom, also called the spiro atom. In particular, the spiro atoms may be sp ³ -hybrid so that the components of the spiro compound connected to each other via the spiro atoms are arranged in different planes, for example with respect to each other.

More preferably, the spiro compound has a structure of the following formula.

Wherein the aryl ¹ , aryl ² , aryl ³ , aryl ⁴ , aryl ⁵ , aryl ⁶ , aryl ⁷ and aryl ⁸ radicals are each independently selected from substituted aryl radicals and heteroaryl radicals, especially substituted phenyl radicals, Wherein the aryl radicals and heteroaryl radicals, preferably phenyl radicals, are each independently substituted, preferably in each case a group consisting of -O-alkyl, -OH, -F, -Cl, -Br and -I Substituted by one or more substituents selected from, wherein alkyl is preferably methyl, ethyl, propyl or isopropyl. More preferably, the phenyl radicals are each independently substituted in each case by one or more substituents selected from the group consisting of -O-Me, -OH, -F, -Cl, -Br and -I.

More preferably, the spiro compound is a compound of the following formula.

Wherein R ^r , R ^s , R ^t , R ^u , R ^v , R ^w , R ^x and R ^y are each independently a group consisting of -O-alkyl, -OH, -F, -Cl, -Br and -I And alkyl is preferably methyl, ethyl, propyl or isopropyl. More preferably, R ^r , R ^s , R ^t , R ^u , R ^v , R ^w , R ^x and R ^y are each independently -O-Me, -OH, -F, -Cl, -Br and -I It is selected from the group consisting of.

In particular, the p-semiconductor or matrix material may comprise spiro-MeOTAD or consist of spiro-MeOTAD, ie a compound of formula (III) sold for example from Merck KGaA, Darmstadt, Germany, Taiwan.

Alternatively or in addition, it is also possible to use other p-semiconducting compounds, in particular low molecular weight and / or oligomeric and / or polymerizable p-semiconducting compounds.

In an alternative embodiment, the low molecular weight organic p-semiconductor or matrix material comprises one or more compounds of formula I described above, eg, PCT Application No. PCT / EP2010 published after the priority date of the present application. / 051826 may be referenced.

The p-semiconductor may comprise at least one compound of the general formula I described above in addition or alternatively to the spiro compounds described above.

The term "alkyl" or "alkyl group" or "alkyl radical" as used in the context of the present invention is generally understood to mean substituted or unsubstituted C ₁ -C ₂₀ -alkyl radicals. C ₁ -to C ₁₀ -alkyl radicals are preferred, and C ₁ -to C ₈ -alkyl radicals are particularly preferred. Alkyl radicals may be straight or branched. In addition, the alkyl radicals are substituted by one or more substituents selected from the group consisting of C ₁ -C ₂₀ -alkoxy, halogen, preferably F, and C ₆ -C ₃₀ -aryl, which may in turn be substituted or unsubstituted. It may be substituted. Examples of suitable alkyl groups are methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl and octyl, and also isopropyl, isobutyl, isopentyl, sec-butyl, tert-butyl, neopentyl, 3,3-dimethylbutyl, 2-ethylhexyl, and also derivatives of the mentioned alkyl groups substituted by C ₆ -C ₃₀ -aryl, C ₁ -C ₂₀ -alkoxy and / or halogen (in particular F), for example CF ₃ .

The term "aryl" or "aryl group" or "aryl radical" as used in the context of the present invention refers to an optionally substituted C ₆ -C ₃₀ -derivative derived from monocyclic, bicyclic, tricyclic or other polycyclic aromatic rings. It is understood to mean aryl radicals, wherein the aromatic rings do not comprise any ring heteroatoms. The aryl radical preferably comprises 5- and / or 6-membered aromatic rings. When the aryls are not monocyclic systems, in the case of the term "aryl" for the second ring, if certain forms are known and stable, they may be in saturated form (perhydro form) or partially saturated form (eg, dihydro). Form or tetrahydro form) is also possible. Thus in the context of the present invention the term "aryl" also includes, for example, bicyclic or tricyclic radicals in which both radicals or all three radicals are aromatic, and in which only one ring is aromatic Formula radicals are also included, and also tricyclic radicals in which the two rings are aromatic. Examples of aryl are phenyl, naphthyl, indanyl, 1,2-dihydronaphthenyl, 1,4-dihydronaphthenyl, fluorenyl, indenyl, anthracenyl, phenanthrenyl or 1,2,3 , 4-tetrahydronaphthyl. Particular preference is given to C ₆ -C ₁₀ -aryl radicals, for example phenyl or naphthyl, very particular preference to C ₆ -aryl radicals, for example phenyl. In addition, the term "aryl" also includes ring systems comprising at least two monocyclic, bicyclic or polycyclic aromatic rings connected to one another via single or double bonds. One example is a ring system of biphenyl groups.

The term "heteroaryl" or "heteroaryl group" or "heteroaryl radical" as used in the context of the present invention refers to optionally substituted 5- or 6-membered aromatic rings and polycyclic rings, for example at least one. It is understood to mean bicyclic and tricyclic compounds having at least one heteroatom in the ring of. Heteroaryls in the context of the present invention preferably comprise 5 to 30 ring atoms. They may be monocyclic, bicyclic or tricyclic, and some can be derived from the above-mentioned aryl by replacing at least one carbon atom in its aryl base skeleton with a heteroatom. Preferred heteroatoms are N, O and S. Heteroaryl radicals more preferably have 5 to 13 ring atoms. The basic skeleton of heteroaryl radicals is particularly preferably selected from systems such as pyridine and 5-membered heteroaromatics such as thiophene, pyrrole, imidazole or furan. These base skeletons may optionally be fused to one or two 6-atomic aromatic radicals. In addition, the term “heteroaryl” also includes ring systems comprising at least two monocyclic, bicyclic or polycyclic aromatic rings connected to one another via single or double bonds, wherein at least one ring comprises a heteroatom . When heteroaryls are not monocyclic systems, in the case of the term “heteroaryl” for at least one ring, if certain forms are known and stable, they may be saturated (perhydro) or partially saturated (eg For example, in dihydro form or tetrahydro form). Thus in the context of the present invention the term “heteroaryl” includes, for example, bicyclic or tricyclic radicals in which both radicals or all three radicals are aromatic, and also in which only one ring is aromatic or Also included are tricyclic radicals, and also tricyclic radicals in which two rings are aromatic, wherein at least one of the rings, ie one aromatic or one nonaromatic ring, has a heteroatom. Suitable fused heteroaromatics are, for example, carbazolyl, benzimidazolyl, benzofuryl, dibenzofuryl or dibenzothiophenyl. The base skeleton may be substituted at one, two or more or all substitutable positions, with suitable substituents being the same as already specified in the definition of C ₆ -C ₃₀ -aryl. However, heteroaryl radicals are preferably unsubstituted. Suitable heteroaryl radicals are, for example, pyridin-2-yl, pyridin-3-yl, pyridin-4-yl, thiophen-2-yl, thiophen-3-yl, pyrrole-2-yl, pyrrole- 3-yl, furan-2-yl, furan-3-yl and imidazol-2-yl and the corresponding benzofused radicals, in particular carbazolyl, benzimidazolyl, benzofuryl, dibenzofuryl or dibenzo Thiophenyl.

The term "optionally substituted" in the context of the present invention refers to radicals in which at least one hydrogen radical of an alkyl group, aryl group or heteroaryl group is replaced by a substituent. As for the type of this substituent, alkyl radicals such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl and octyl, and also isopropyl, isobutyl, isopentyl, sec-butyl, tert-butyl, Neopentyl, 3,3-dimethylbutyl and 2-ethylhexyl, aryl radicals such as C ₆ -C ₁₀ -aryl radicals are preferred, in particular phenyl or naphthyl, most preferably C ₆ -aryl radicals For example phenyl, and heteroaryl radicals such as pyridin-2-yl, pyridin-3-yl, pyridin-4-yl, thiophen-2-yl, thiophen-3-yl, pyrrole-2 -Yl, pyrrole-3-yl, furan-2-yl, furan-3-yl and imidazol-2-yl, and also the corresponding benzofused radicals, in particular carbazolyl, benzimidazolyl, benzofuryl , Dibenzofuryl or dibenzothiophenyl. Further examples include the following substituents: alkenyl, alkynyl, halogen, hydroxyl.

The degree of substitution here may vary from a single substitution to the maximum number of possible substituents.

Preferred compounds of formula I for use according to the invention are those wherein at least two of the R ¹ , R ² and R ³ radicals are para-OR and / or -NR ₂ Note that they are substituents. Wherein at least two radicals may be only -OR radicals, may be only -NR ₂ radicals, or may be at least one -OR and at least one -NR ₂ radical.

Particularly preferred compounds of formula I for use according to the invention are those wherein at least 4 of the R ¹ , R ² and R ³ radicals are para-OR and / or -NR ₂ Note that they are substituents. Wherein at least four radicals may be only -OR radicals, may be only -NR ₂ radicals, or may be a mixture of -OR and -NR ₂ radicals.

Very particularly preferred compounds of formula I for use according to the invention are those in which all of the R ¹ , R ² and R ³ radicals are para-OR and / or -NR ₂ Note that they are substituents. They may be -OR radicals only, -NR ₂ radicals, or a mixture of -OR and -NR ₂ radicals.

In all cases, two R in —NR ₂ radicals may be different from each other, but they are preferably the same.

Preferably, A ¹ , A ² and A ³ are each independently,

Is selected from the group consisting of

here

m is an integer from 1 to 18,

R ⁴ is alkyl, aryl or heteroaryl, where R ⁴ is preferably an aryl radical, more preferably a phenyl radical,

R ⁵ , R ⁶ are each independently H, alkyl, aryl or heteroaryl,

Aromatic and heteroaromatic rings of the structures shown herein may optionally have additional substitutions. The degree of substitution of the aromatic and heteroaromatic rings herein may vary from a single substitution up to the maximum number of possible substituents.

Preferred substituents in case of further substitution of aromatic and heteroaromatic rings include the substituents mentioned above for one, two or three optionally substituted aromatic or heteroaromatic groups.

Preferably, the aromatic and heteroaromatic rings of the structures shown have no further substitution.

More preferably, A ¹ , A ² and A ³ are each independently,

ego,

More preferably

to be.

More preferably, at least one compound of formula (I) has one of the following structures:

In an alternative embodiment, the matrix material is ID322, ie a compound of formula (IV) below.

Compounds for use according to the invention can be prepared by the general methods of organic synthesis known to those skilled in the art. References to related (patent) literature can be found further in the synthetic examples presented below.

At least one of the electrodes may be transparent. For example, the first electrode may be a working electrode and the second electrode may be a counter electrode, or vice versa. One or both of these electrodes may be transparent. The photovoltaic device may in particular comprise at least one layer structure provided on a substrate, in which case the layer structure comprises a first electrode, an n-semiconductive metal oxide, a dye, a solid organic p-semiconductor with a metal oxide, and At least one second electrode may be included in the mentioned order or in the reverse order.

The n-semiconductive metal oxide may be particularly porous, in which case at least one buffer layer of the metal oxide may be introduced, in particular, between the n- semiconductive metal oxide and the first electrode. This buffer layer may be, for example, an impermeable layer, that is, a non-particle layer. For example, this buffer layer may be provided by a PVD process, such as a vapor deposition process and / or a sputtering process. Alternatively or in addition, it is also possible to use other processes, for example CVD processes and / or spray pyrolysis processes. On the other hand, the n-semiconductive metal oxide is preferably provided by a paste process, for example by providing printing, spin-coating or knife-coating of a paste of n-semiconductive metal oxide. This paste can then be sintered by at least one heat treatment step, for example by heating above 200 ° C., in particular by above 400 ° C., for example by 450 ° C. This sintering can, for example, remove the volatile components of the paste, preferably leaving only n-semiconductive metal oxide particles.

As mentioned above, dyes may be provided especially for n-semiconductive metal oxides. This provision provides that the dye is n-semiconductive metal oxide layer, for example by means of one or more dye layers, for example monolayers, formed on these particles in order to sensitize the particles of n-semiconductive metal oxide. For example, it is preferably carried out to completely or partially penetrate the particle layer. The provision of the dye may thus be effected, for example, by at least one impregnation process, for example by immersing the sample comprising the n- semiconductive metal oxide layer into the dye solution. Other impregnation processes are also available.

As a particular advantage of the invention, the photovoltaic device may in particular comprise at least one encapsulation. In contrast to conventional photovoltaic devices in which solid p-semiconductors are doped with oxygen (eg by preservation under air), silver in oxidized form, for example at least one silver (I) salt [Ag ⁺ ] _m [A ^{m −} ], particularly preferably p-semiconductors doped with silver bis (trifluoromethylsulfonyl) imide, may also be present without such an oxygen atmosphere over a long period of time. Thus, it is possible to provide encapsulation that hides photovoltaic elements, in particular electrodes and / or p-semiconductors, from the ambient atmosphere. In this way, in the oxidized form, for example at least one of silver (I) salt _{^{[Ag +] m [A m}} -], and particularly preferably is (methylsulfonyl-trifluoromethyl) doped already by de-bis In addition to an improvement in the properties of the p-semiconductor by oxygen, oxygen can be excluded, for example to protect one or more of the electrodes from the adverse effects resulting from oxygen and / or other ambient gases. For example, electrode degradation can be prevented in this way. Encapsulates may include, for example, encapsulated by solid capsule elements, for example capsules with at least one depression or planar encapsulation, provided in the layer structure in such a way as to completely or partially surround the layer structure. It may be. For example, the edges of the encapsulation may completely or partially surround the layer structure and may be bonded to the substrate, for example by adhesive bonds and / or other bonds, preferably cohesive bonds. Alternatively or in addition, the encapsulation may also include one or more layers of material that prevent harmful environmental influences, such as penetration of moisture and / or oxygen. For example, organic and / or inorganic coatings may be provided in the layer structure. Covering from the ambient atmosphere may generally be understood to mean slowing the penetration of moisture and / or gases from the ambient atmosphere into the layered structure. Slowing may be effected in such a way that the concentration differences in and out of the encapsulate extend in a few hours, preferably in a few days, in particular extending from weeks, months to years.

The dye solar cell may additionally have at least one passivation material in particular between the n-semiconductive metal oxide and the p-semiconductor. This passivation material may in particular be set to at least partially prevent electron transfer between the n-semiconductive metal oxide and the p-semiconductor. The passivation material is in particular Al ₂ O ₃ ; Silanes, in particular CH ₃ SiCl ₃ ; Organometallic complexes, especially Al ^{3 +} complex, 4-tert- butyl-pyridine; It may also be selected from hexadecylmalonic acid.

As mentioned above, in a further aspect of the present invention, a process for producing a solid organic p-semiconductor for use in organic components is proposed. This organic component may in particular be a photovoltaic device, for example a photovoltaic device, in particular a dye solar cell, in one or more of the configurations described above. However, other configurations of organic components are also possible in principle, including organic light emitting diodes, organic transistors, and other types of photovoltaic devices, for example end use in organic solar cells.

In the proposed process, at least one p-conductive organic matrix material, for example a matrix material of the type described above, and at least an oxidized form of silver, preferably at least one of the formula [Ag ⁺ ] _m [A ^m- ] The silver (I) salt is provided to at least one carrier element from at least one liquid phase. As described above, p-conductive organic matrix material is understood to mean an organic material that can transport positive charges and preferably be provided from solution. These positive charges are already present in the matrix material and may only be increased by p-doping, or may also be obtained as a result of p-doping with silver in actual oxidized form. In particular, the matrix material may be stably reversibly oxidizable and may be set to shift positive charges (“holes”) towards other molecules, eg, adjacent molecules of the same type.

In general, it is shown in this respect that the effect of the silver salt is only based on the observable effects of the increase in p-conductivity. Thus, it is possible to increase the mobility and / or charge carrier density of the positive charges in the p-semiconductor, for example, by the addition of silver in oxidized form. The present invention is not limited to the manner in which p-doping is carried out at the micro level.

As at least one organic matrix material, and a p- dopant, of an oxidized form, especially formula _{^{[Ag +] m [A m}} -] of at least one of silver (I) salt is preferably, as described above, at least Together from at least one liquid phase to at least one carrier element. Carrier elements may be understood to mean pure substrates, for example glass and / or plastic and / or laminate substrates. Alternatively or additionally, however, the carrier element may also comprise further elements, for example one or more electrodes and / or one or more layers, which may already be provided in the substrate. For example, the p-semiconductor may be provided from the liquid phase in a layer structure already partially or completely completed, in which case, for example, one or more layers may already be provided in the substrate, and then the p-semiconductor At least one layer of is provided. For example, as described above in connection with a photovoltaic device, before the p-semiconductor is provided from at least one liquid phase, at least one first electrode, at least one n-semiconducting metal oxide and preferably a dye It may already be provided on the substrate.

Provision from the liquid phase generally involves, for example, a wet chemical processing operation, for example spin-coating, knife-coating, casting, printing or similar wet chemical processes or combinations of the processes mentioned and / or other processes. It may also include. For example, it is possible to use printing processes such as inkjet printing, screen printing, offset printing and the like. Drying of the p-semiconductor may be carried out in particular following provision from the liquid phase, for example to remove volatile components such as solvents in the liquid phase. This drying can be carried out, for example, under thermal action, for example at temperatures of 30 ° C to 150 ° C. However, other configurations are also possible in principle.

As described above, the matrix material may in particular comprise, for example, at least one low molecular weight organic p-semiconductor as matrix material. In particular, it is possible to use one or more of the aforementioned organic p-semiconductors. In particular, the low molecular weight organic p-semiconductor may comprise at least one triphenylamine. The low molecular weight organic p-semiconductor may in particular comprise at least one spiro compound, for example one or more of the spiro compounds described above.

The liquid phase, in addition to at least one matrix material and oxidized form of silver, in particular at least one silver (I) salt of the formula [Ag ⁺ ] _m [A ^m- ], may also have one or more additional end uses which may have constant end uses. It may further comprise components. For example, it is known to use spiro compounds, for example Spiro-MeOTAD, as a solution with at least one lithium salt, for the purpose of improving electrical properties and / or for stabilization purposes. In general, the liquid phase may thus further comprise at least one metal salt, for example. In particular, this may be an organometallic salt. Combinations of different salts are also possible. In particular, it is possible to use lithium salts, for example organometallic lithium salts, preferably LiN (SO ₂ CF ₃ ) ₂ .

As mentioned above, the at least one liquid phase may in particular comprise at least one solvent. In the context of the present invention, the term “solvent” means whether all, some or the individual components present in the liquid phase are actually in dissolved form or they are in other forms, for example suspensions, dispersions, emulsions or It is used here whether or not it exists as some other form. In particular, in an oxidized form, for example at least one of silver (I) salt _{^{[Ag +] m [A m}} -], and particularly preferably is (methylsulfonyl-trifluoromethyl) bis present in dissolved form imide It may be. For example, at least one matrix material may be present in dissolved or otherwise dispersed form. Of the oxidized form, for example at least one of silver (I) salt _{^{[Ag +] m [A m}} -], most preferably bis (trifluoromethyl sulfonyl) may be in particular a soluble type polyimide In principle, however, they may also exist in other forms, for example in dispersed and / or suspended form.

Particular preference is given to using at least one organic solvent. In particular, the following solvents: cyclohexanone; Chlorobenzene; Benzofuran; And cyclopentanone.

The proposed process for producing solid organic p-semiconductors can be used to produce the above-mentioned photovoltaic devices, in particular in one or more of the described configurations. However, other organic components can also be manufactured by this process. Combinations with other known processes are also conceivable in principle, so that, for example, when a plurality of organic p-semiconductors are provided, one or more of these p-semiconductors are proposed in accordance with the present invention. And one or more of the conventional p-semiconductors can be manufactured by other processes.

A particular advantage of the proposed process for producing solid organic p-semiconductors is that, in contrast to many processes known from the prior art, preservation under air is not necessary. For example, the process may in particular be carried out at least partially in a low-oxygen atmosphere. In the context of the present invention, an organic component is generally understood to mean a component having one or more organic elements, for example one or more organic layers. It is possible to use organic components, for example components in which the layer structure-optionally except electrodes-comprise only organic layers. However, it is also possible to fabricate components comprising hybrid components, for example one or more organic layers, as well as one or more inorganic layers. If the proposed process is used to produce solid organic p-semiconductors in a multi-step manufacturing process, it is possible to carry out one, two or more or all of the process steps for the preparation of organic components in a low-oxygen atmosphere. In particular, in contrast to the known processes described above, the process steps of the preparation of the solid organic p-semiconductor can be carried out in a low-oxygen atmosphere. In particular, the provision of the liquid phase to the carrier element can thus be carried out in a low-oxygen atmosphere. Low-oxygen atmosphere is generally understood to mean an atmosphere having a reduced oxygen content compared to the surrounding air. For example, the low-oxygen atmosphere may have an oxygen content of less than 1000 ppm, preferably an oxygen content of less than 500 ppm, more preferably an oxygen content of less than 100 ppm, for example 50 ppm or less. Under this low-oxygen atmosphere, it is also possible to carry out further processing of organic components, for example dye solar cells. For example, at least after the provision of the solid p-semiconductor by the proposed process, the low-oxygen atmosphere cannot be stopped again until after encapsulation. Full processing of the entire component in a low-oxygen atmosphere is also possible without adversely affecting the electrical properties of the component. Particular preference is given to providing a low-oxygen atmosphere in the form of an inert gas, for example a nitrogen atmosphere and / or an argon atmosphere. Mixed gases are also available.

As mentioned above, in a third aspect of the present invention, a process for manufacturing a photovoltaic device is proposed. This may in particular be a photovoltaic device, for example a dye solar cell, according to one or more of the above mentioned configurations. The proposed process for manufacturing a photovoltaic device may be carried out using the process described above, in particular for producing a solid organic p-semiconductor, in which case the process for manufacturing a solid organic p-semiconductor It can be used more than once in the context of the proposed process for manufacturing. However, the use of other processes is also possible in principle.

The proposed process preferably has the process steps described below, which are preferably but not necessarily performed in the order described. Individual or several process steps may also be performed in time overlapping and / or in parallel. It is also possible to carry out additional process steps not described. In the proposed process, at least one first electrode, at least one n-semiconductive metal oxide, at least one dye absorbing electromagnetic radiation, at least one solid organic p-semiconductor and at least one second electrode are provided. . This provision may be effected, for example, in the order mentioned. In particular, such provision can be effected, for example, by making a layer structure according to the above description. This layer structure can for example be built up continuously on one or more substrates. In this case, it is also possible to combine one or more of the elements mentioned to provide a combined layer, for example n-semiconductive metal oxide and dye.

In the proposed process, p- semiconductor is of the oxidized form, for example at least one of silver (I) salt _{^{[Ag +] m [A m}} -], and particularly preferably is (methylsulfonyl-trifluoromethyl) bis It is configured to include an imide. p- semiconductor, in particular the oxidized form of, for example, at least one of silver (I) salt _{^{[Ag +] m [A m}} -], and particularly preferably is (methylsulfonyl-trifluoromethyl) bis imide It may also include at least one organic matrix material that is doped by. Of the organic matrix material and / or oxidized form, for example at least one of silver (I) salt _{^{[Ag +] m [A m}} -] of the imide, and particularly preferably is (methylsulfonyl-trifluoromethyl) bis For possible configurations, reference may be made to the description above and below.

The p-semiconductor can be produced in particular by the process in which wet chemical processing operations are used, for example according to the above description of the process for producing solid organic p-semiconductors. In the wet-chemical processing operations, as at least one of the p- conductive organic matrix material and a p- dopant, of an oxidized form, for example at least one of silver (I) salt _{^{[Ag +] m [A m}} -], Particularly preferably silver bis (trifluoromethylsulfonyl) imide can be provided together from at least one liquid phase to at least one carrier element.

Thereafter, other selectively implementable configurations of photovoltaic elements and their processes which are particularly preferred in the context of the present invention are described. However, other configurations are also possible in principle.

The photovoltaic device may in particular comprise a layer structure, which may for example be provided on a substrate. In this case, for example, the first electrode or the second electrode may face the substrate. At least one of the electrodes must be transparent. A “transparent” electrode in this context means that there is at least 50% transmission, preferably at least 80% transmission, especially within the visible spectral range and / or the range of the solar spectrum (approximately 300 nm to 2000 μs nm). It should be understood to. If the substrate is a transparent substrate, in particular the electrode facing the substrate should be transparent.

The substrate may be, for example, a glass substrate and / or a plastic substrate or may comprise a glass substrate and / or a plastic substrate. However, other materials including combinations of different materials, for example laminates, are also available in principle. The components of the photovoltaic device may be provided as layers directly or indirectly to the substrate. In the context of the present invention, the terms "carrier element", "carrier" and "substrate" are used at least substantially synonymously. However, in the case where a carrier element is being discussed, this rather highlights the possibility that a layer is being provided indirectly to the substrate, such that there may be at least one additional element, in particular at least one additional layer, between the layer to be provided and the actual substrate. have. However, direct provision is also possible.

The photovoltaic device may in particular be a dye solar cell. Thus, photovoltaic devices are also referred to hereinafter as "cells" in general terms, without imposing any restrictions on the particular layer structure. The cell may in particular comprise at least one first electrode, n-conductive metal oxide, dye, p-semiconductor and second electrode. n-conductive metal oxides, dyes and p-semiconductors may also be referred to as functional layers that may be embedded between the electrodes. In addition, the cell may comprise one or more additional layers which may likewise be assigned to functional layers, for example. One or more cells may be provided directly or indirectly to the substrate. The photovoltaic device may in particular comprise one cell or a plurality of cells in addition. In particular, a single-cell structure may be selected, or a multi-cell structure, for example a tandem cell structure, in which a plurality of cells are arranged in parallel and / or on a substrate, may be selected.

In particular, the photovoltaic device according to the invention may be constructed in one or more of the following ways. The configurations of the elements of the photovoltaic device can also be combined in virtually any way.

First electrode and n− Semiconductivity  Metal oxide

The n-semiconductive metal oxide used in dye solar cells may be a single metal oxide or mixtures of different oxides. It is also possible to use mixed oxides. The n-semiconductive metal oxide may be particularly porous and / or used in the form of nanoparticle oxides, where nanoparticles are understood to mean particles having an average particle size of less than 0.1 micrometers. Nanoparticle oxides are typically provided to a conductive substrate (ie, a carrier having a conductive layer as the first electrode) by a sintering process as a porous thin film having a large surface area.

The substrate may be rigid or otherwise flexible. Suitable substrates (hereinafter also referred to as carriers) are not only metal foils, but also especially plastic sheets or films and in particular glass sheets or glass films. Particularly suitable electrode materials for the first electrode according to the above-described preferred structure are conductive materials, for example transparent conductive oxides (TCOs), for example fluorine- and / or indium-doped tin oxide (FTO or ITO) and / or aluminum-doped zinc oxide (AZO), carbon nanotubes or metal films. Alternatively or in addition, it would also be possible to use metal thin films that still have sufficient transparency. The substrate may be covered or coated with these conductive materials. Since only a single substrate is generally required in the proposed structure, formation of flexible batteries is also possible. This enables a number of end uses that are difficult to achieve and, if possible, only achievable by rigid substrates used, for example, in bank cards, garments and the like.

The first electrode, in particular the TCO layer, may additionally be covered or coated with a solid metal oxide buffer layer (eg 10 to 200 nm thick) to prevent the p-semiconductor from directly contacting the TCO layer (Peng et. al ., Coord. Chem. Rev. 248, 1479 (2004). However, in comparison to liquid or gel-type electrolytes, the use of the solid p-semiconducting electrolytes of the present invention is in many cases when the contact of the first electrode with the solid p-semiconducting electrolyte of the invention is greatly reduced. By making this buffer layer unnecessary, it is possible to omit this buffer layer, which also has a current-limiting effect and can also worsen the contact between the first electrode and the n-semiconducting metal oxide. This improves the efficiency of the components. On the other hand, such a buffer layer can in turn be used in a controlled manner to match the current component of the dye solar cell to the current component of the organic solar cell. In addition, in the case of cells in which the buffer layer has been omitted, in particular in solid cells, problems with unwanted recombination of charge carriers often arise. In this regard, buffer layers are in many cases particularly advantageous in solid cells.

As is well known, thin layers or thin films of metal oxides are generally inexpensive solid semiconductor materials (n-semiconductors), but due to the large bandgaps, their absorption is usually not in the visible region of the electromagnetic spectrum, rather usually It is in the ultraviolet spectral region. As in the case of dye solar cells, for use in solar cells, the metal oxides are thus generally absorbed in the wavelength range of sunlight, ie 300-2000 GHz nm, and in an electronically excited state, Must be combined with a dye as a photosensitizer, which injects them into the conduction zone of the semiconductor. The electrons can be recycled to the sensitizer with the aid of a solid p-semiconductor additionally used in this cell as an electrolyte, which is eventually reduced at the counter electrode (or in the transition to the second subcell in the case of tandem solar cells), It is played.

Of particular interest among semiconductors for use in solar cells are zinc oxide, tin dioxide, titanium dioxide or mixtures of these metal oxides. Metal oxides can be used in the form of nanocrystalline porous layers. These layers have a large surface area coated with a dye as a sensitizer, so that high absorption of sunlight is achieved. For example with nanorods, structured metal oxide layers offer advantages such as higher electron mobility or improved pore filling by dyes.

Metal oxide semiconductors may be used alone or in the form of mixtures. It is also possible to coat the metal oxide with one or more other metal oxides. In addition, metal oxides may also be provided as a coating for other semiconductors, for example GaP, ZnP or ZnS.

Particularly preferred semiconductors are zinc oxide and titanium dioxide in the anatase polymorph, which is preferably used in nanocrystalline form.

In addition, sensitizers can be advantageously combined with all n-semiconductors that are commonly found in use in these solar cells. Preferred examples include metal oxides used in ceramics, such as titanium dioxide, zinc oxide, tin (IV) oxide, tungsten (VI) oxide, tantalum (V) oxide, niobium (V) oxide, cesium oxide, strontium titanate Complex oxides of the zinc stannate, perovskite type, for example barium titanate, and binary and ternary iron oxides, which may also be present in nanocrystalline or amorphous form.

Due to the strong absorption of common organic dyes and phthalocyanines and porphyrins, even thin layers or thin films of n-semiconductive metal oxide are sufficient to absorb the required amount of dye. Metal oxide thin films in turn have the advantage that the likelihood of unwanted recombination processes is reduced and the internal resistance of the dye subcell is reduced. For n-semiconducting metal oxides, it is possible to preferably use a range of layer thicknesses from 100 nm to 20 nm micrometers, more preferably between 500 nm and about 3 micrometers.

dyes

In the context of the present invention, usually for DSCs, the terms "dye", "sensitizer dye" and "sensitizer" are used synonymously without any limitation of the possible configurations. Many dyes usable in the context of the present invention are known from the prior art, and for possible material examples, reference may also be made to the above description of the prior art with regard to dye solar cells. All dyes listed and claimed may in principle also be present as pigments. Dye-sensitized solar cells based on titanium dioxide as a semiconductor material are described, for example, in US Pat. No. 4,927,721, Nature 353, p. 737-740 (1991) and US-A-5 350 644, and also Nature 395, p. 583-585 (1998) and EP-A-1 # 176 # 646. The dyes described in these documents can in principle also be advantageously used in the context of the present invention. These dye solar cells preferably comprise monolayers of transition metal complexes, in particular ruthenium complexes, which are bonded to the titanium dioxide layer via acid groups as sensitizers.

Particularly for reasons of cost, the sensitizers proposed several times include metal-free organic dyes, which are likewise usable in the context of the present invention. Especially in solid dye solar cells, high efficiencies above 4% can be achieved, for example, by indolin dyes (eg Schmidt-Mende et. al ., Adv. Mater. 2005, 17, 813). US-A-6 359 211 discloses the use of cyanine, oxazine, thiazine and acridine dyes having carboxyl groups bound via an alkylene radical for fixing to a titanium dioxide semiconductor, which is also feasible in the context of the present invention. This is described.

Organic dyes currently achieve an efficiency of nearly 12.1% in liquid cells (eg, P. Wang et. al ., ACS. Nano 2010). Pyridinium-containing dyes have also been reported and can be used in the context of the present invention and exhibit promising efficiency.

Particularly preferred sensitizer dyes in the proposed dye solar cells are the perylene derivatives, terylene derivatives and quaternylene derivatives described in DE 10 2005 053 995 A1 or WO 2007/054470 A1. The use of these dyes results in photovoltaic devices having high efficiency and at the same time high stability.

Reylenes exhibit strong absorption in the wavelength range of sunlight and, depending on the length of the conjugated system, from about 400 nm (perylene derivatives I from DE 10 2005 053 995 A1) to about 900 nm (DE 10 2005 053 995 A1 May cover the range of quaterylene derivatives I). Terylene-based reylene derivatives I, depending on their composition, absorb in the solid state adsorbed on titanium dioxide within the range of about 400 to 800 nm. In order to achieve a large utilization of incident sunlight from the visible region to the near infrared region, it is advantageous to use mixtures of different rylene derivatives I. In some cases, it may also be advisable to use different rylene homologs.

The rylene derivatives I can be fixed in a permanent manner and easily to the n-semiconductive metal oxide film. The linkage is effected via anhydride function (x1) or in situ formed carboxyl groups -COOH or -COO- or via acid groups A present in the imide or condensation radicals ((x2) or (x3)). The rylene derivatives I described in DE # 10 2005 053 995 A1 have good suitability for use in dye-sensitized solar cells in the context of the present invention.

Dyestuffs are particularly preferred when at one end of the molecule they have anchor groups that allow fixation to the n-semiconductor membrane. At the other end of the molecule, the dyes preferably comprise electron donors Y which facilitate the regeneration of the dye after the electrons are released to the n-semiconductor and also prevent recombination with electrons already released into the semiconductor.

For further details regarding the possible selection of suitable dyes, it is also possible to refer, for example, to DE 10 2005 053 995 A1. For the tandem cells described in this document, it is possible in particular to use ruthenium complexes, porphyrins, other organic sensitizers, and preferably rylenes.

The dyes may be fixed onto or into the n-semiconductive metal oxide films in a simple manner. For example, n-semiconductor metal oxide films may be contacted with a suspension or solution of dye in a suitable organic solvent for a sufficient period of time (eg, about 0.5 to 24 kPa) in a freshly sintered (continuously warmed) state. Can be. This can be accomplished, for example, by immersing the metal oxide-coated substrate in a solution of the dye.

When different combinations of dyes are used, they may be provided continuously, for example, from one or more solutions or suspensions comprising one or more of the dyes. It is also possible to use two dyes separated by, for example, a layer of CuSCN (for this topic, see, eg, Tennakone, K.J., Phys. Chem. B. 2003, 107, 13758). The most convenient method can be determined relatively easily in the individual case.

In the selection of the size of the oxide particles of the n-semiconductive metal oxide and the selection of the dye, the solar cell should be configured to absorb the maximum amount of light. The oxide layers must be structured so that the solid p-semiconductor can efficiently fill the pores. For example, smaller particles have larger surface areas, so that more dyes can be adsorbed. On the other hand, larger particles generally have larger pores which allow for better penetration through the p-conductor.

As mentioned above, the proposed concept involves the use of one or more solid p-semiconductors. To prevent electrons in the n-semiconductor metal oxide from recombining with the solid p-conductor, it is possible to use at least one passivation layer with a passivation material between the n-semiconductor metal oxide and the p-semiconductor. Do. This layer should be very thin and cover only as far as possible uncovered portions of the n-semiconductive metal oxide. This passivation material may in some cases also be provided to the metal oxide prior to dyeing. Preferred passivation materials are in particular the following materials: Al ₂ O ₃ ; Silanes, for example CH ₃ SiCl ₃ ; Al ^{+ 3;} 4-tert-butylpyridine (TBP); MgO; GBA (4-guanidinobutyric acid) and similar derivatives; Alkyl acids; At least one of hexadecylmalonic acid (HDMA).

p-semiconductor

As mentioned above, in the context of the photovoltaic device proposed herein, one or more solid organic p-semiconductors are used alone or in combination with one or more additional p-semiconductors of organic or inorganic nature. As mentioned above, at least one solid organic p-semiconductor comprises at least an oxidized form of silver. In the context of the present invention, p-semiconductor is generally understood to mean a material, in particular an organic material, capable of conducting holes. In particular, it may be an organic material having a vast π-electron system that can be oxidized stably at least once, for example to form what are called free-radical cations. For example, the p-semiconductor may comprise at least one organic matrix material having the mentioned properties. In particular, the p-semiconductor may be p-doped with silver (I). This means that any p-semiconductor properties present in the p-semiconductor or in some cases in the matrix material are improved or even actually produced by doping with silver (I). In particular, doping can increase the charge carrier density, in particular the hole density. Alternatively or in addition, the mobility of the charge carriers, in particular the mobility of the holes, can also be influenced by doping, in particular increased.

In particular, as described above, the doped p-semiconductor may be or may be prepared by providing at least one p-conductive organic material and an oxidized form of silver to the at least one carrier element, wherein the oxidized form of silver Preferably provided in at least one carrier element in the form of at least one silver (I) salt [Ag ⁺ ] _m [A ^{m −} ] wherein A ^{m −} is an anion of an organic or inorganic acid and m is in the range of 1 to 3 Is an integer of preferably m is 1.

With respect to the integer m, it is preferable that m is 1 or 2, and it is very preferable that it is 1. Thus, for the production of p- semiconductor, formula Ag ⁺ A ^- it is highly desirable to use a salt of a.

With regard to A ^{m −} , it is preferred that this is an anion of an organic or inorganic acid.

In a preferred embodiment, A ^{m −} is an anion of an organic acid, the organic acid preferably comprising at least one fluorine group or cyano group (—CN), and more preferably at least one fluorine group. Preferably, [A ^{m −} ] is an anion of an organic carboxylic acid, sulfonic acid, phosphonic acid or sulfonimide, each preferably including at least one fluorine group or cyano group.

Preferably, as described above, the present invention relates to a photovoltaic device, wherein [A ^m- ] has a structure of the following formula (II).

R ^a is a fluorine group (-F), or an alkyl radical, a cycloalkyl radical, an aryl radical or a heteroaryl radical, each substituted by at least one fluorine group or cyano group,

X is -O ^- or -N ^-- R ^b ,

R ^b contains a fluorine group (-F) or a cyano group,

R ^b further includes a group of the formula —S (O) ₂ —.

The term "cycloalkyl radical" or "cycloalkyl group" as used in the context of the present invention refers to cyclic, optionally substituted alkyl groups, preferably 5- or 6-membered rings, or more preferably 5 to 20 carbon atoms. To polycyclic rings having

R ^a Radical :

In a preferred embodiment of the invention, R ^a is -F, or an alkyl radical substituted by at least one fluorine group or one cyano group, preferably by at least one fluorine group, very preferably at least one It is a fluorine group or a cyano group, Preferably the methyl group, ethyl group, or propyl group substituted by the fluorine group. In addition to the fluorine group or cyano group, the alkyl radical may comprise at least one additional substituent. Preferably, R ^a comprises at least three fluorine substituents or one cyano group, more preferably at least three fluorine substituents.

R ^a is in particular selected from the group consisting of -F, -CF ₃ , -CF ₂ -CF ₃ and -CH ₂ -CN, more preferably a group consisting of -F, -CF ₃ and -CF ₂ -CF ₃ Is selected from.

Therefore, as described above, the present invention also relates to a photovoltaic device, wherein [A ^m− ] has a structure selected from the following formulas.

Where X is -O ^- or -N ^-- R ^b . More preferably, R ^a is -CF ₃ .

R ^b Radical :

As mentioned above, R ^b is a group comprising a fluorine group (—F) or a cyano group, and R ^b further comprises a group of the formula —S (O) ₂ —. Preferably, R ^b comprises at least one alkyl, cycloalkyl, aryl or heteroaryl radical, wherein the alkyl, cycloalkyl, aryl or heteroaryl radical is in each case at least one fluorine group (—F) or cyan Substituted by a furnace group, preferably by at least one fluorine group, wherein R ^b further comprises a group of the formula -S (O) _2- .

Preferably, R ^b has a structure of the following formula.

R ^bb is -F, or an alkyl group substituted by at least one fluorine group or cyano group, preferably at least one fluorine group, very preferably a methyl group, ethyl group or propyl group substituted by at least one fluorine group. In addition to the fluorine group and / or cyano group, the alkyl radical may comprise at least one additional substituent. Preferably, R ^bb comprises at least three fluorine substituents.

R ^bb is especially selected from the group consisting of -F, -CF ₃ , -CF ₂ -CF ₃ and -S (O) ₂ -CH ₂ -CN, in particular -F, -CF ₃ and -CF ₂ -CF ₃ It is selected from the group consisting of.

Thus, as described above, the present invention also relates to a photovoltaic device, wherein X is -N ^-- R ^b , and R ^b is -S (O) ₂ -F, -S (O) ₂ -CF ₃ , -S (O) ₂ -CF ₂ -CF ₃ and -S (O) ₂ -CH ₂ -CN, in particular -S (O) ₂ -F, -S (O) ₂ -CF ₃ And -S (O) ₂ -CF ₂ -CF ₃ .

[A ^{m −} ] is therefore most preferably having one of the following structures.

R ^{a in} particular is selected from the group consisting of -F, -CF ₃ and -CF ₂ -CF ₃ . Preferably, X is -N ^-- R ^b and R ^b is

In the case of structures, R ^a and R ^bb are the same; [A ^{m −} ] is therefore more preferably symmetric sulfonyl imide. In a preferred embodiment, [A ^{m −} ] is thus bis (trifluoromethylsulfonyl) imide (TFSI ⁻ ), bis (trifluoroethylsulfonyl) imide, and bis (fluorosulfonyl) imide Is selected from the list.

In an alternative embodiment, the invention relates to a photovoltaic device as described above, wherein [A ^{m −} ] is a trifluoroacetate group.

In another preferred embodiment, [A ^{m −} ] is an anion of an inorganic acid. In this case, [A ^{m -]} is preferably -NO ₃ ^- is (nitrate). Therefore, the present invention also at least one of silver (I) salt [Ag ^+] _m in at least one organic matrix material 128, as described above [A ^{m -]} by introducing, in particular mixing and / or dissolving by, relates to a photovoltaic element is made available, or prepared, [a ^{m -]} is -NO ₃ ^- is a group and m = 1.

Accordingly, the invention also relates to a photovoltaic element as described above, [A ^m-] is bis (trifluoromethyl sulfonyl) imide (TFSI ^-), bis (trifluoro-ethyl-sulfonyl) imide , Bis (fluorosulfonyl) imide, trifluoromethylsulfonate, and preferably [A ^{m −} ] is bis (trifluoromethylsulfonyl) imide (TFSI ⁻ ).

Particularly when dyes absorb strongly and thus require only n-semiconductor thin layers, at least in the oxidized form of silver, for example at least one silver (I) salt [Ag ⁺ ] _m [even without any large increase in cell resistance. A ^{m −} ], particularly preferably solid p-semiconductors doped with silver bis (trifluoromethylsulfonyl) imide can be used in the photovoltaic devices of the invention. In particular, the p-semiconductor can be used to reduce unwanted recombination reactions that can result in contact between the second electrode and / or additional elements of the photovoltaic device and the n-semiconductive metal oxide (especially in nanoporous form). In essence it should have a continuous opaque layer.

Of the oxidized form, for example at least one of silver (I) salt _{^{[Ag +] m [A m}} -], and particularly preferably is (methylsulfonyl-trifluoromethyl) bis from the liquid phase with the particular matrix material imide It may be provided to the carrier element. For example, in the oxidized form, for example at least one of silver (I) salt _{^{[Ag +] m [A m}} -], and particularly preferably is (methylsulfonyl-trifluoromethyl) imide, bis p- In combination with the semiconductive matrix material, it can be processed as a solution, dispersion or suspension. Optionally, at least one organic salt may be added (although it is also possible for some liquid phases to be presented), for example for the purpose of improving electrical properties and / or for stabilization purposes.

An important parameter that affects the selection of p-semiconductors is hole mobility, because it determines hole diffusion length in part (see Kumara, G., Langmuir, 2002, 18, 10493-10495). Comparison of charge carrier mobilities for different spiro compounds is described, for example, in T. Saragi, Adv. Funct. Mater. 2006, 16, 966-974.

Preferably, in the context of the present invention, organic semiconductors (ie low molecular weight, oligomeric or polymeric semiconductors or mixtures of such semiconductors) are used. Particular preference is given to p-semiconductors which can be processed from the liquid phase. Examples here include polymers such as polythiophene and polyarylamines, or the spirobifluorenes mentioned at the beginning (see eg US 2006/0049397, as p-semiconductors there also usable in the context of the present invention). P-semiconductors based on amorphous, reversibly oxidizable, nonpolymerizable organic compounds, such as the disclosed spiro compounds). It is desirable to use low molecular weight organic semiconductors. Solid p- semiconductors as a dopant, in the oxidized form, for example at least one of silver (I) salt _{^{[Ag +] m [A m}} -], and particularly preferably is (methylsulfonyl-trifluoromethyl) bis already Can be used in the doped form.

In addition, references may also be made to p-semiconductive materials and dopants from the prior art description. For other possible elements and possible structures of the dye solar cell, reference may also be made generally to the above description.

The second electrode

The second electrode may be a lower electrode facing the substrate or else an upper electrode away from the substrate. The second electrodes that can be used are in particular metal electrodes, which may have one or more metals, such as aluminum or silver, in pure form or as a mixture / alloy. The use of inorganic / organic mixed electrodes or multilayer electrodes is also possible, for example the use of LiF / Al electrodes.

In addition, it is also possible to use electrode designs in which the quantum efficiency of the components is increased by photons that are forced to pass through the absorbing layers at least twice by appropriate reflections.

Such layer structures are also called "condensers" and are likewise described in WO # 02/101838 (especially p. # 23-24).

Other details and features of the invention are apparent from the following description of the preferred embodiments in connection with the dependent claims. In this context, certain features may be implemented alone or in some combination. The invention is not limited to the embodiments. Embodiments are schematically illustrated in the drawings. Like reference numerals in the individual drawings refer to like elements or elements having the same function, or elements corresponding to each other with respect to their functions.
1 is a side cross-sectional view showing a schematic layer structure of the organic photovoltaic device of the present invention.
FIG. 2 shows a schematic arrangement of energy levels in the layer structure according to FIG. 1.
3 shows the current-voltage characteristics of a comparative sample without silver in oxidized form, measured after two days of preparation.
4 shows current-voltage characteristics with Ag-TFSI doping.

Examples

FIG. 1 shows in a very schematic cross-sectional view a photovoltaic element 110, which is a dye solar cell 112 in this embodiment. The photovoltaic device 110 according to the schematic layer structure of FIG. 1 may be constructed in accordance with the present invention. Comparative samples according to the prior art may in principle also correspond to the structure shown in FIG. 1, for example, may differ only with respect to solid organic p-semiconductors. However, it is noted that the invention is also applicable to other layer structures and / or in other configurations.

The photovoltaic element 110 comprises a substrate 114, for example a glass substrate. As mentioned above, other substrates are also available. This substrate 114 is provided with a transparent first electrode 116, also referred to as a working electrode and preferably as described above. This first electrode 116 is in turn provided with a blocking layer 118 of selective metal oxide, which is preferably nonporous and / or non-particle. This in turn is provided with n-semiconductive metal oxide 120 sensitized with dye 122.

The substrate 114 and the layers 116-120 provided thereon form a carrier element 124 for at least one layer provided thereon of the solid organic p-semiconductor 126, and the solid organic p-semiconductor (126) in turn represents at least one p-semiconducting organic matrix material 128 and at least one oxidized form of silver 130, for example at least one silver (I) salt [Ag ⁺ ] _m [A ^{m -} ], Particularly preferably silver bis (trifluoromethylsulfonyl) imide. This p-semiconductor 126 is provided with a second electrode 132, also referred to as a counter electrode. The layers shown in FIG. 1 together form a layer structure 134, which layer encapsulates 136, for example, to completely or partially protect the layer structure 134 from oxygen and / or moisture. ) Is shielded from the ambient atmosphere. In order to be able to provide one or more contact connection regions outside of the encapsulation 136, one or both of the electrodes 116, 132 may be encapsulated, as shown in FIG. 1 with reference to the first electrode 116. 136 may be guided out.

2 shows, by way of example, an energy level diagram of the photovoltaic element 110 according to FIG. 1 in a very schematic manner. Fermi levels 138 of the first electrode 116 and the second electrode 132 are shown, with the p-semiconductor 126 (HTL, also referred to as the hole transport layer) and with a dye (HOMO level 5.7 eV) Shown are examples of high occupied molecular orbitals (HOMOs) 140 and lower unoccupied molecular orbitals (LUMOs) of layers 118/120 (which may include the same material, for example TiO ₂ ). Materials specified as examples for the first electrode 116 and the second electrode 132 are FTO (fluorine-doped tin oxide) and silver.

Photovoltaic devices may also optionally include additional elements. By means of photovoltaic elements 110 with or without encapsulation 136, the embodiments described hereinafter are embodied, on the basis of which the effect of the invention and in particular the p- The effect of p-doping of the semiconductor 126 can be demonstrated.

Comparison sample

As comparative samples of photovoltaic devices, dye solar cells with solid p-semiconductors not dope with silver in oxidized form, as are known in principle from the prior art, have been prepared.

As the base material and substrate, using glass plates coated with fluorine-doped tin oxide (FTO) as the first electrode (working electrode) and having dimensions of 25 mm x 25 mm x 3 mm (Hartford Glass) in an ultrasonic bath. Treatment with glass cleaner (RBS 35), demineralized water and acetone at 5 minutes in succession was followed by boiling in isopropanol for 10 minutes and drying in a nitrogen stream.

To produce an optional solid TiO ₂ buffer layer, a spray pyrolysis process was used. On the other hand, as an n- semiconductive metal oxide, a TiO ₂ paste (Dyesol) containing TiO ₂ particles having a diameter of 25 nm in a terpineol / ethylcellulose dispersion was spun on at a spin-coater at 4500 rpm, and 30 It dried for 90 minutes at 90 degreeC. After the step of heating to 450 ° C. for 45 minutes and sintering at 450 ° C. for 30 minutes, a TiO ₂ layer of approximately 1.8 μm in thickness was obtained.

After controlling from a drying cabinet, the sample is cooled to 80 ° C., immersed in a 5 μmM solution of additive ID662 (eg obtainable according to example H) for 12 hours and subsequently dye in dichloromethane It was immersed in 0.5 mM solution of for 1 hour. The dye used was dye ID504 (for example obtainable according to example G). After removal from solution, the sample was subsequently rinsed with the same solvent and dried in a stream of nitrogen. Samples obtained in this way were subsequently dried at 40 ° C. under reduced pressure.

Next, the p-semiconductor solution was spun on. For this purpose, a solution of 0.12 M Spiro-MeOTAD (Merck) and 20 mM LiN (SO ₂ CF ₃ ) ₂ (Aldrich) in chlorobenzene was prepared. 125 μl of this solution was provided to the sample and allowed to work for 60 seconds. The supernatant solution was then spun off at 2000 rpm for 30 seconds and the sample was kept under air for dark overnight. As mentioned above, such preservation results in oxygen doping of the p-semiconductor, and as a result it is believed that the conductivity of the p-semiconductor is improved.

Finally, the metal back electrode was provided as the second electrode by thermal metal evaporation under reduced pressure. The metal used was Ag, which was evaporated at a rate of 3 kV / s at a pressure of approximately 2 * 10 ^-6 mbar to give a layer thickness of about 200 nm.

After manufacture, the cells were stored for 2 days under dry air (8% relative atmospheric humidity).

To determine the efficiency (η), specific current / voltage characteristics were measured with a source meter model 2400 (Keithley Instruments Inc.) under irradiation with a xenon solar simulator (LOT-Oriel 300 W AM 1.5) two days after manufacture. Initial measurements were taken on unencapsulated cells. The current-voltage characteristic of the comparative sample measured after 2 days is shown in FIG. 3. The comparative sample had the properties shown in Table 1.

Table 1: Properties of undoped comparative sample

The short-circuit current Isc (i.e. current density at zero load resistance) was 9.29 mA / cm ² , the open circuit voltage V _oc (i.e. load at zero current density) was 860 mV and fill factor FF was 55 % And efficiency ETA was 4%.

Example 1: 5 mM AG - TFSI  Doping

As a first embodiment of the photovoltaic device 110 of the present invention, p-semiconductor 126 or its matrix material 128 is replaced with bis (trifluoromethylsulfonyl) imide (Ag-) for the comparative sample described above. Modified by doping with TFSI). For this purpose, 5 mM silver bis (trifluoromethylsulfonyl) imide (source: Aldrich) in cyclohexanone, 0.12M spiro-MeOTAD (source: Merck) and 20 mM LiN (in chlorobenzene) To a p-semiconductor solution of BO ₂ CF ₃ ) ₂ (Source: Aldrich). This solution was then spun on to the sample as described for the comparative sample.

The metal back electrode as the second electrode 132 was then immediately provided by thermal metal evaporation under reduced pressure. The metal used was Ag, which was evaporated at a rate of 3 kV / s at a pressure of approximately 2 * 10 ^-6 mbar to give a layer thickness of about 200 nm.

To determine the efficiency (η), specific current / voltage characteristics were measured with a source meter model 2400 (Keithley Instruments Inc.) immediately after manufacture and 2 days later under irradiation by a xenon solar simulator (LOT-Oriel 300 mW AM 1.5). . Initial measurements were taken on unencapsulated cells.

5 μmM shows the current-voltage characteristics for bis (trifluoromethylsulfonyl) imide in FIG. 4. The properties of the comparative sample and the sample according to example 1 are shown in Table 2.

Table 2: Comparison of properties of undoped comparative sample and sample according to example 1 at different measurement times

Example 2: Dopant  Change of concentration

In order to study the effect of the amount of dopant on the properties of the photovoltaic device 110, the modifications of Example 1 were also made using bis (trifluoromethylsulfonyl) imide of 1-20 mM. Otherwise, these samples were prepared as the samples according to Example 1 described above. The properties of these samples measured after 2 days are shown in Table 3. The illuminance in these measurements was again 100 Sun in each case, as in the above measurements.

Table 3: Comparison of the properties of the samples according to Example 2 with different Ag-TFSI content

These measurements indicate that, in terms of efficiency, a maximum efficiency of approximately 5.1% occurs at approximately 10 μm Ag-TFSI. Overall, an efficiency between 3 μmM and 20 μmM may follow a relatively flat profile, which may be advantageous in terms of manufacturing techniques.

Example 3: change of matrix material

Also as Example 3, the influence of the matrix material 128 on the characteristics of the photovoltaic elements 110 was studied. For this purpose, Spiro-MeOTAD as matrix material 128 is replaced by different matrix materials 128 with different concentrations, in particular by matrix materials of the above-described ID522, ID322 and ID367 types. Except for the above, samples were prepared according to Example 1 described above. To introduce the silver 130 in oxidized form, the dopant used was again 10 μmM bis (trifluoromethylsulfonyl) imide in all samples in each case. The properties of the samples obtained in this way are shown in Table 4. The specified concentrations of 160 μg mg / ml and 200 μg mg / ml are based on the concentration of the matrix material 128 in the liquid phase. Properties were recorded again after 2 days and measured at 100 μs Sun [mW / cm 2].

Table 4: Comparison of the properties of the samples according to example 4 with different matrix materials

Example 4: Dopant  change

In addition, tests were conducted to introduce the oxidized form of silver 130 into the matrix material 128 by other dopants. In addition, in order to ascertain whether the doping effect on the properties of the photovoltaic devices 110 and its positive effect is possibly caused by TFSI instead of silver 130 in the oxidized form, in Ag-TFSI Was replaced by other groups.

For this purpose, in Example 4, except for the dopant, various samples corresponding to Example 1 were prepared again. However, instead of Ag-TFSI, other salts as dopants were added in amounts of 20 μmM each. The results are shown in Table 5. Silver nitrate was added to the p-conductor solution in solid form.

Table 5: Comparison of the properties of the samples according to example 5 with different dopants

The results generally indicate that TFSI causes high efficiency only when it is an anion in silver salt. However, in addition to Ag-TFSI, other silver salts also show relatively high efficiencies, especially silver nitrate and silver triflate. In general, therefore the compound containing the oxidized form as the dopant, in particular salts, particularly formula _{^{[Ag +] m [A m}} -] of the Ag-TFSI is that (I) salts, and more preferably, silver nitrate, and It is possible to use triflate.

Finally, examples of synthesis of low molecular weight organic p-semiconductors, which can be used individually or in combination in the context of the present invention and for example can satisfy the formula I given above, are also listed below.

Synthesis Examples

(A) Expression Of I  General Synthetic Modes for the Preparation of Compounds

(a) Synthetic route I:

(a1) Synthesis Step I-R1:

Synthesis in Synthesis Step I-R1 was based on the references cited below:

a) Liu, Yunqi; Ma, Hong; Jen, Alex K-Y .; CHCOFS; Chem. Commun .; 24; 1998; 2747-2748,

b) Goodson, Felix E .; Hauck, Sheila; Hartwig, John F .; J. Am. Chem. Soc .; 121; 33; 1999; 7527-7539,

c) Shen, Jiun Yi; Lee, Chung Ying; Huang, Tai-Hsiang; Lin, Jiann T .; Tao, Yu-Tai; Chien, Chin-Hsiung; Tsai, Chiitang; J. Mater. Chem .; 15; 25; 2005; 2455-2463,

d) Huang, Ping-Hsin; Shen, Jiun-Yi; Pu, Shin-Chien; Wen, Yuh-Sheng; Lin, Jiann T .; Chou, Pi-Tai; Yeh, Ming-Chang P .; J. Mater. Chem .; 16; 9; 2006; 850-857,

e) Hirata, Narukuni; Kroeze, Jessica E .; Park, Taiho; Jones, David; Haque, Saif A .; Holmes, Andrew B .; Durrant, James R .; Chem. Commun .; 5; 2006; 535-537.

(a2) Synthesis Step I-R2:

Synthesis in Synthesis Step I-R2 was based on the references cited below:

a) Huang, Qinglan; Evmenenko, Guennadi; Dutta, Pulak; Marks, Tobin J .; J. Am. Chem. Soc .; 125; 48; 2003; 14704-14705,

b) Bacher, Erwin; Bayerl, Michael; Rudati, Paula; Reckefuss, Nina; Mueller, C. David; Meerholz, Klaus; Nuyken, Oskar; Macromolecules; EN; 38; 5; 2005; 1640-1647,

c) Li, Zhong Hui; Wong, Man Shing; Tao, Ye; D'Iorio, Marie; J. Org. Chem .; EN; 69; 3; 2004; 921-927.

(a3) Synthesis Step I-R3:

Synthesis in Synthesis Steps I-R3 was based on the references cited below:

J. Grazulevicius; J. of Photochem. and Photobio., A: Chemistry 2004 162 (2-3), 249-252.

Compounds of formula I can be prepared via the sequence of synthetic steps indicated above in synthetic route I. In steps (I-R1) to (I-R3), the reactants can be coupled, for example, by a Ullmann reaction with copper as a catalyst or under palladium catalysis.

(b) synthetic route II:

(b1) Synthesis Step II-R1:

Synthesis in Synthesis Stage II-R1 was based on the references cited in Synthesis Stage I-R2.

(b2) Synthesis Stage II-R2:

Synthesis in Synthesis Step II-R2 was based on the references cited below:

, C. David; Meerholz, Klaus; Nuyken, Oskar; Macromolecules; 38; 5; 2005; 1640 - 1647,a) Bacher, Erwin; Bayerl, Michael; Rudati, Paula; Reckefuss, Nina;

, C. David; Meerholz, Klaus; Nuyken, Oskar; Macromolecules; 38; 5; 2005; 1640-1647,

b) Goodson, Felix E .; Hauck, Sheila; Hartwig, John F .; J. Am. Chem. Soc .; 121; 33; 1999; 7527-7539; Hauck, Sheila I .; Lakshmi, K. V .; Hartwig, John F .; Org. Lett .; One; 13; 1999; 2057-2060.

(b3) Synthesis Step II-R3:

Compounds of formula I can be prepared via the sequence of synthetic steps indicated above in synthetic route II. In steps (II-R1) to (II-R3), the reactants can also be coupled by Ullmann reaction with copper as catalyst or for example under palladium catalysis, as in synthesis route I.

(c) Preparation of starting amines:

If the diarylamines in the synthesis steps I-R2 and II-R1 of the synthetic routes I and II are not commercially available, they are for example Ullmann with copper as a catalyst or under palladium catalysis, according to the following reactions. Can be produced by reaction.

Synthesis was based on the review papers listed below:

Pallanium-catalyzed C-N coupling reactions:

a) Yang, Buchwald; J. Organomet. Chem. 1999, 576 (1-2), 125-146,

b) Wolfe, Marcoux, Buchwald; Acc. Chem. Res. 1998, 31, 805-818,

c) Hartwig; Angew. Chem. Int. Ed. Engl. 1998, 37, 2046-2067.

Copper-catalyzed C-N coupling reactions:

a) Goodbrand, Hu; Org. Chem. 1999, 64, 670-674,

b) Lindley; Tetrahedron 1984, 40, 1433-1456.

(B) Synthesis Example 1: Compound Of ID367  Synthesis (Synthetic Path I)

(B1): Synthesis step according to general synthesis scheme I-R1:

4,4'-dibromobiphenyl (93.6 g; 300 mmol) in toluene, 4-methoxyaniline (133 g; 1.08 mol), Pd (dppf) Cl ₂ (Pd (1,1'-bis (diphenyl) A mixture of phosphino) ferrocene) Cl ₂ ; 21.93 g; 30 mmol) and t-BuONa (sodium tert-butoxide; 109.06 g; 1.136 mol) was stirred at 110 ° C. for 24 hours under a nitrogen atmosphere. After cooling, the mixture was diluted with diethyl ether and filtered through a Celite® pad (manufactured by Carl Roth). The filter bed was washed with 1500 ml each of ethyl acetate, methanol and methylene chloride. The product was obtained as a light brown solid (36 g; yield: 30%).

(B2): Synthesis step according to general synthesis scheme I-R2:

Dppf (1,1'-bis (diphenyl-phosphino) ferrocene; 0.19 g; 0.34 mmol) and Pd ₂ (dba) ₃ (tris (dibenzylideneacetone) -dipalladium (0) in toluene (220 ml) 0.15 g; 0.17 mmol) through a nitrogen solution for 10 minutes. Subsequently t-BuONa (2.8 g; 29 mmol) was added and the reaction mixture was stirred for an additional 15 minutes. Then 4,4'-dibromobiphenyl (25 g; 80 mmol) and 4,4'-dimethoxydiphenylamine (5.52 g; 20 mmol) were added sequentially. The reaction mixture was heated at a temperature of 100 ° C. for 7 hours under a nitrogen atmosphere. After cooling to room temperature, the reaction mixture was quenched with ice water and the precipitated solid was filtered off and dissolved in ethyl acetate. The organic layer was washed with water, dried over sodium sulfate and purified by column chromatography (eluent: 5% ethyl acetate / hexanes). A pale yellow solid was obtained (7.58 g, yield: 82%).

(B3): synthesis step according to the general synthesis mode I-R3:

N ⁴ , N ⁴ '-bis (4-methoxyphenyl) biphenyl-4,4'-diamine (product from synthesis step I-R1; 0.4 g; 1.0 mmol) and product from synthesis step I-R2 ( 1.0 g; 2.2 mmol) was added to a solution of t-BuONa (0.32 g; 3.3 mmol) in o-xylene (25 ml) under nitrogen atmosphere. Subsequently, a 10% by weight solution of P (t-Bu) ₃ (tris-t-butylphosphine) in palladium acetate (0.03 g; 0.14 mmol) and hexane (0.3 ml; 0.1 mmol) was added to the reaction mixture And stirred at 125 ° C. for 7 hours. The reaction mixture was then diluted with 150 ml of toluene and filtered through Celite® and the organic layer was dried over Na ₂ S0 ₄ . The solvent was removed and the crude product was reprecipitated three times from a mixture of tetrahydrofuran (THF) / methanol. The solid was purified by column chromatography (eluent: 20% ethyl acetate / hexane), followed by purification with THF / methanol and activated carbon purification. After removal of the solvent, the product was obtained as a pale yellow solid (1.0 g, yield: 86%).

(C) Synthesis Example 2: Compound Of ID447  Synthetic (Synthetic Path II )

(C1): Synthesis step according to general synthesis scheme II-R2:

p-anisidine (5.7 g, 46.1 mmol), t-BuONa (5.5 g, 57.7 mol) and P (t-Bu) ₃ (0.62 ml, 0.31 mmol) in synthesis step I-R2 in toluene (150 ml) To a solution of the product from (17.7 g, 38.4 mmol). After nitrogen was passed through the reaction mixture for 20 minutes, Pd ₂ (dba) ₃ (0.35 g, 0.38 mmol) was added. The resulting reaction mixture was left to stir at room temperature under nitrogen atmosphere for 16 hours. Subsequently, it was diluted with ethyl acetate and filtered through Celite®. The filtrate was washed twice with 150 ml each of water and saturated sodium chloride solution. After drying the organic phase over Na ₂ S0 ₄ and removing the solvent, a black solid was obtained. This solid was purified by column chromatography (eluent: 0-25% ethyl acetate / hexanes). This gave an orange solid (14 g, yield: 75%).

(C2): synthesis step according to general synthesis mode II-R3:

t-BuONa (686 mg; 7.14 mmol) was heated at 100 ° C. under reduced pressure, after which the reaction flask was purged with nitrogen and cooled to room temperature. Then 2,7-dibromo-9,9-dimethylfluorene (420 mg; 1.19 mmol), toluene (40 ml) and Pd [P ( ^t Bu) ₃ ] ₂ (20 mg; 0.0714 mmol) were added The reaction mixture was stirred at room temperature for 15 minutes. Subsequently, N, N, N′-p-trimethoxytriphenylbenzidine (1.5 g; 1.27 mmol) was added to the reaction mixture and stirred at 120 ° C. for 5 hours. The mixture was filtered through a Celite® / MgSO ₄ mixture and washed with toluene. The crude product was purified twice by column chromatography (eluent: 30% ethyl acetate / hexanes) and after two reprecipitations from THF / methanol a pale yellow solid was obtained (200 mg, yield: 13%).

(D) Synthesis Example 3: Compound Of ID453  Synthesis (Synthetic Path I)

(D1): Preparation of Initial Amine:

Step 1:

To a mixture of 2-bromo-9H-fluorene (120 g; 1 eq) and BnEt ₃ NCl (benzyltriethylammonium chloride; 5.9 g; 0.06 eq) in 580 ml of DMSO (dimethyl sulfoxide) NaOH (78 g; 4 eq) was added. The mixture was cooled with ice water and methyl iodide (MeI) (160 g; 2.3 eq) was slowly added dropwise. The reaction mixture was stirred overnight, then poured into water and subsequently extracted three times with ethyl acetate. The combined organic phases were washed with saturated sodium chloride solution, dried over Na ₂ SO ₄ , and the solvent was removed. The crude product was purified by column chromatography using silica gel (eluent: petroleum ether). After washing with methanol, the product (2-bromo-9,9'-dimethyl-9H-fluorene) was obtained as a white solid (102 g).

Step 2:

p-anisidine (1.23 g; 10.0 mmol) and 2-bromo-9,9'-dimethyl-9H-fluorene (3.0 g; 11.0 mmol) were added to t-BuONa (1.44 g) in 15 ml (15 ml) of toluene. 15.0 mmol) was added under a nitrogen atmosphere. A 10 wt% solution of P (t-Bu) ₃ in hexane (0.24 ml; 0.08 mmol) and Pd ₂ (dba) ₃ (92 mg; 0.1 mmol) were added and the reaction mixture was stirred at rt for 5 h. Subsequently, the mixture was quenched with ice water and the precipitated solid was filtered off and dissolved in ethyl acetate. The organic phase was washed with water and dried over Na ₂ S0 ₄ . After the crude product was purified by column chromatography (eluent: 10% ethyl acetate / hexanes) a pale yellow solid was obtained (1.5 g, yield: 48%).

(D2): Preparation of compound ID453 for use according to the present invention

(D2.1): Synthesis steps according to general synthesis scheme I-R2:

The product from a) (4.70 g; 10.0 mmol) and 4,4'-dibromobiphenyl (7.8 g; 25 mmol) were added to a solution of t-BuONa (1.15 g; 12 mmol) in 50 ml of toluene under nitrogen. Added. Pd ₂ (dba) ₃ (0.64 g; 0.7 mmol) and DPPF (0.78 g; 1.4 mmol) were added and the reaction mixture was stirred at 100 ° C. for 7 hours. After quenching the reaction mixture with ice water, the precipitated solid was filtered off and it was dissolved in ethyl acetate. The organic phase was washed with water and dried over Na ₂ S0 ₄ . After the crude product was purified by column chromatography (eluent: 1% ethyl acetate / hexane), a pale yellow solid was obtained (4.5 g, yield: 82%).

(D2.2): Synthesis steps according to general synthesis scheme I-R3:

N ⁴ , N ⁴ '-bis (4-methoxyphenyl) biphenyl-4,4'-diamine (0.60 g; 1.5 mmol) and the product from the preceding synthetic step I-R2 (1.89 g; 3.5 mmol), To a solution of t-BuONa (0.48 g; 5.0 mmol) in 30 ml of o-xylene was added under nitrogen. 10 wt% solution of P (t-Bu) ₃ in hexane (0.62 ml; 0.21 mmol) and palladium acetate (0.04 g; 0.18 mmol) were added and the reaction mixture was stirred at 125 ° C. for 6 h. Subsequently, the mixture was diluted with 100 ml of toluene and filtered through Celite®. The organic phase was dried over Na ₂ S0 ₄ and the solid obtained was purified by column chromatography (eluent: 10% ethyl acetate / hexanes). Reprecipitation from THF / methanol was then carried out to give a pale yellow solid (1.6 g, yield: 80%).

(E) Other compounds of formula I for use according to the invention:

The compounds listed below were obtained similarly to the above synthesis:

(E1) Synthesis Example 4: Compound ID320

(E2) Synthesis Example 5: Compound ID321

(E3) Synthesis Example 6: Compound ID366

(E4) Synthesis Example 7: Compound ID368

(E5) Synthesis Example 8: Compound ID369

(E6) Synthesis Example 9: Compound ID446

(E7) Synthesis Example 10: Compound ID450

(E8) Synthesis Example 11: Compound ID452

(E9) Synthesis Example 12: Compound ID480

(E10) Synthesis Example 13: Compound ID518

(E11) Synthesis Example 14 Compound ID519

(E12) Synthesis Example 15 Compound ID521

(E13) Synthesis Example 16: Compound ID522

(E14) Synthesis Example 17 Compound ID523

(E15) Synthesis Example 18 Compound ID565

(E16) Synthesis Example 19: Compound ID568

(E17) Synthesis Example 20: Compound ID569

(E18) Synthesis Example 21: Compound ID572

(E19) Synthesis Example 22: Compound ID573

(E20) Synthesis Example 23: Compound ID575

(E21) Synthesis Example 24: Compound ID629

(E22) Synthesis Example 25: Compound ID631

(F) formula IV  Synthesis of Compounds:

(a) Coupling of p-anisidine and 2-bromo-9,9-dimethyl-9H-fluorene

0.24 ml (0.08 mmol) of P (t-Bu) ₃ (d = 0.68 g / ml) and 0.1 g of Pd ₂ (dba) ₂ [= (tris (dibenzylideneacetone) dipalladium (0)] (0.1 mmol) was added 10 ml to 15 ml of toluene (anhydride, 99.8%) and the mixture was stirred for 10 minutes at room temperature 1.44 g (15 mmol) of sodium tert-butoxide (97.0%) were added, The mixture was stirred for an additional 15 minutes at room temperature, followed by 2.73 g (11 mmol) of 2-bromo-9,9-dimethyl-9H-fluorene and the reaction mixture was stirred for an additional 15 minutes. , 1.23 g (10 mmol) of p-anisidine was added and the mixture was stirred at 90 ° C. for 4 hours.

The reaction mixture was mixed with water and the product precipitated out of hexane. The aqueous phase was also extracted with ethyl acetate. The filtered precipitated solid and organic phase were combined and purified by column chromatography on SiO ₂ phase (10: 1 hexanes: ethyl acetate).

1.5 mg (yield: 47.6%) of a yellow solid was obtained.

(b) coupling of tris (4-bromophenyl) amine with the product from (a)

To 0.2 ml (0.07 mmol) of P (t-Bu) ₃ (D = 0.68 g / ml) and 0.02 g (0.1 mmol) of palladium acetate are added 25 ml of toluene (anhydride) and the mixture is stirred at room temperature for 10 minutes. Stirred. 0.4 g (1.2 mmol) of sodium tert-butoxide (97.0%) were added and the mixture was stirred for an additional 15 minutes at room temperature. Subsequently, 0.63 g (1.3 mmol) of tris (4-bromophenyl) amine were added and the reaction mixture was stirred for an additional 15 minutes. Finally, 1.3 g (1.4 mmol) of product from step (a) were added and the mixture was stirred at 90 ° C. for 5 hours.

The reaction mixture was mixed with cold ice water and extracted with ethyl acetate. The product was precipitated from a mixture of hexanes / ethyl acetate and purified by column chromatography on SiO ₂ (9: 1-> 5: 1 hexanes: ethyl acetate change).

0.7 mg (yield: 45%) of yellow product was obtained.

(G) compounds Of ID504  synthesis:

Preparation was carried out from (4-bromophenyl) bis (9,9-dimethyl-9H-fluoren-2-yl) (see Chemical Communications, 2004, 68-69), first 4,4,5,5, 4 ', 4', 5 ', 5'-octamethyl- [2,2'] ratio [[1,3,2] dioxaborolanyl] (step a). Then coupling with 9Br-DIPP-PDCI was performed (step b). Hydrolysis was then performed to give an anhydride (step c), followed by reaction with glycine to give the final compound (step d).

Step a:

30 g (54 mmol) of (4-bromophenyl) bis (9,9-dimethyl-9H-fluoren-2-yl), 41 g (162 mmol) of 4,4,5,5,4 ', 4 ', 5', 5'-octamethyl- [2,2 '] ratio [[1,3,2] dioxaborolanyl], 1 g (1.4 mmol) of Pd (dpf) ₂ Cl ₂ , 15.9 A mixture of g (162 mmol) of potassium acetate and 300 ml of dioxane was heated to 80 ° C. and stirred for 36 hours.

After cooling, the solvent was removed and the residue was dried at 50 ° C. in a vacuum drier.

Purification was carried out by filtration through silica gel using eluent 1: 1 n-hexane: dichloromethane. After removal of the reactants, the eluent was changed to dichloromethane. The product was isolated as a reddish and sticky residue. It was extracted by stirring with methanol for 0.5 h at room temperature. The pale colored precipitate was filtered off. After drying at 45 ° C. in a vacuum drier, 24 kg of a pale solid was obtained, corresponding to a yield of 74%.

Analytical data

Step b:

17.8 g (32 mmol) of 9Br-DIPP-PDCI and 19 ml (95 mmol) of 5 molar NaOH were introduced into 500 ml of dioxane. The mixture was degassed with argon for 30 minutes. 570 mg (1.1 mmol) of Pd [P (tBu) ₃ ] ₂ and 23 g (38 mmol) of step a were then added and the mixture was stirred at 85 ° C. for 17 h under argon.

Purification was performed by column chromatography using eluent 4: 1 dichloromethane: toluene.

22.4 g of a purple solid was obtained, corresponding to 74% yield.

Analytical Data:

Step c:

22.4 g (23 mmol) of step b and 73 g (1.3 mol) of KOH were introduced into 200 ml of 2-methyl-2-butanol and the mixture was stirred at reflux for 17 h.

After cooling, the reaction mixture was added to 1 L ice water + 50 mL ml of concentrated acetic acid. The orange brown solid was filtered through frit and washed with water.

The solid was dissolved in dichloromethane and extracted with demineralized water. 10 mL of concentrated acetic acid was added to the organic phase and stirred at room temperature. The solvent was removed from the solution. The residue was extracted by stirring with methanol for 30 minutes at room temperature, filtered by suction through a frit and dried at 55 ° C. in a vacuum drier.

This gave 17.5 g of a purple solid corresponding to 94% yield.

The crude product was used in the next step.

Step d:

17.5 g (22 mmol) of step c, 16.4 g (220 mmol) of glycine and 4 g (22 mmol) of zinc acetate were introduced into 350 ml of N-methylpyrrolidone and the mixture was stirred at 130 ° C. for 12 hours. Stirred.

After cooling, the reaction mixture was added to 1 liter of demineralized water. The precipitate was filtered through frit, washed with water and dried at 70 ° C. in a vacuum drier.

Purification was performed by column chromatography using eluent 3: 1 dichloro-methane: ethanol + 2% triethylamine. The separated product was extracted by stirring with 50% acetic acid at 60 ° C. The solid was filtered by suction through the frit, washed with water and dried at 80 ° C. in a vacuum drier.

7.9 g of a purple solid corresponding to a yield of 42% was obtained.

Analytical Data:

(H) compounds Of ID662  synthesis:

ID662 was produced by reacting the corresponding commercially available hydroxamic acid [2- (4-butoxyphenyl) -N-hydroxyacetamide] with sodium hydroxide.

110: photovoltaic device
112: Dye Solar Cell
114: substrate
116: first electrode
118: blocking layer
120: n-semiconductive material
122: dye
124: carrier element
126: p-semiconductor
128: Matrix Material
130: silver in oxidized form
132: second electrode
134: layer structure
136: capsule
138: Fermi Level
140: HOMO
142: LUMO
144: Properties for comparative samples without silver in oxidized form, t = 0
146: Properties for comparative samples without silver in oxidized form, t = 2 days
148: Characteristic for sample of Example 1, t = 0
150: characteristics for the sample of Example 1, t = 2 days

Claims (20)

As photovoltaic element 110, in particular dye solar cell 112, for converting electromagnetic radiation into electrical energy,
The photovoltaic device 110 comprises at least one first electrode 116, at least one n-semiconductive metal oxide 120, at least one electromagnetic radiation-absorbing dye 122, at least one solid organic p- A semiconductor 126 and at least one second electrode 132,
The p-semiconductor (126) comprises silver in oxidized form. The method of claim 1,
The p-semiconductor is manufacturable or has been prepared by applying at least one p-conductive organic material 128 and silver in oxidized form to at least one carrier element,
The silver was sputtered at least one of silver (I) salt _{^{[Ag +] m [A m}} -] preferably provided in the form of and, A ^{m -} is the anion of an organic or inorganic acid and m is an integer in the range of 1 to 3 , Preferably m is 1. 3. The method of claim 2,
The silver was sputtered at least one of silver (I) salt [Ag ^+] _m ^- is provided in the form ^{of, [A m] [A m} -] is an anion of an organic acid, preferably the organic acid is at least one fluorine group (- F) or a photovoltaic device having a cyano group. The method of claim 3, wherein
[A ^{m -]} has a structure of the formula (II),

R ^a is a fluorine group (-F), or an alkyl radical, a cycloalkyl radical, an aryl radical or a heteroaryl radical, each substituted by at least one fluorine group or cyano group,
X is -O ^- or -N ^-- R ^b ,
R ^b contains a fluorine group (-F) or a cyano group,
R ^b further comprises a group of the formula —S (O) ₂ —. 5. The method of claim 4,
R ^a is selected from the group consisting of —F, —CF ₃ , —CF ₂ —CF _3, and —CH ₂ —CN. The method according to claim 4 or 5,
X is -N ^-- R ^b ,
R ^b is selected from the group consisting of -S (O) ₂ -F, -S (O) ₂ -CF ₃ , -S (O) ₂ -CF ₂ -CF _3, and -S (O) ₂ -CH ₂ -CN. Selected, photovoltaic device. 6. The method according to any one of claims 3 to 5,
[A ^{m −} ] is bis (trifluoromethylsulfonyl) imide (TFSI ⁻ ), bis (trifluoroethylsulfonyl) imide, bis (fluorosulfonyl) imide and trifluoromethylsulfonate is selected from the group, preferably consisting of [a ^{m -]} is (methylsulfonyl trifluoromethanesulfonyl) imide (TFSI ^-) of bis, the photovoltaic element. The method of claim 3, wherein
[A ^{m -]} acetate is due trifluoromethyl, photovoltaic elements. The method of claim 3, wherein
[A ^{m −} ] is NO ₃ ⁻ , a photovoltaic device. 9. The method according to any one of claims 3 to 8,
The p-semiconductor is preparable or manufactured by providing at least one carrier element with at least one p-conductive organic material 128 and at least one silver (I) salt [Ag ⁺ ] _m [A ^{m −} ] was, the service (application) is as defined in at least one of the p- conductive organic material and the at least one silver (I) salt _{^{[Ag +] m [a m}} -] carried out by the film formation (deposition) from a liquid phase comprising the Photovoltaic device. 11. The method of claim 10,
The liquid phase comprises at least one solvent, in particular an organic solvent, in particular cyclohexanone; Chlorobenzene; Benzofuran; And a solvent selected from cyclopentanone. The method of claim 11,
Ag ⁺ and preferably also anionic compound [A ^{m −} ] are present in an essentially homogeneous distribution in the matrix material (128). 13. The method according to claim 11 or 12,
The matrix material (128) comprises at least one low molecular weight organic p-semiconductor (126). 12. The method according to any one of claims 2 to 11,
The p-conductive organic material 128 comprises a spiro compound, in particular spiro-MeOTAD, and / or a compound having the structure

A ¹ , A ² and A ³ are each independently, optionally substituted aryl groups or heteroaryl groups,
R ¹ , R ² and R ³ are each independently selected from the group consisting of substituents -R, -OR, -NR ₂ , -A ⁴ -OR and -A ⁴ -NR ₂ ,
R is selected from the group consisting of alkyl, aryl and heteroaryl,
A ⁴ is an aryl group or heteroaryl group,
In each case in formula (I) n is independently a value of 0, 1, 2 or 3,
Provided that the sum of the individual n values is at least 2 and at least two of the R ¹ , R ² and R ³ radicals are —OR and / or —NR ₂ . 15. The method according to any one of claims 1 to 14,
Further comprises at least one encapsulation,
The encapsulation is designed to shield the photovoltaic device (110), in particular the electrodes (116, 132) and / or the p-semiconductor (126) from the ambient atmosphere. The method of claim 10 or 11,
The liquid phase comprises the at least one silver (I) salt [Ag ⁺ ] _m [A ^{m −} ] at a concentration of 0.5 mM / ml to 50 mM / ml, more preferably 1 mM / ml to 20 mM / A photovoltaic device comprising at a concentration of ml. As a method of producing a solid organic p-semiconductor 126 for use in an organic component, in particular in the photovoltaic device 110 according to any one of claims 1 to 16,
At least one of the p- conductive organic matrix material 128 and at least the oxidized form is preferably at least one of silver (I) salt _{^{[Ag +] m [A m}} -] is at least one from the at least one liquid Provided to the carrier element,
[A] ^- is an anion of an organic or inorganic acid,
Compound _{^{[Ag +] m [A m}} -] is preferably AgNO _3, or is (methylsulfonyl-trifluoromethyl) bis imide of a method of manufacturing a solid organic semiconductor p-. The method of claim 17,
The liquid phase comprises at least one solvent, in particular an organic solvent, in particular cyclohexanone; Chlorobenzene; Benzofuran; And a solvent selected from cyclopentanone. The method according to claim 17 or 18,
Wherein said method of producing a solid organic p-semiconductor is carried out at least partially in a low oxygen atmosphere. As a method of manufacturing the photovoltaic device 110, in particular the photovoltaic device 110 according to any one of claims 1 to 16,
In the method of manufacturing the photovoltaic device, at least one first electrode 116, at least one n-semiconductive metal oxide 120, at least one electromagnetic radiation-absorbing dye 122, at least one solid organic p A semiconductor 126 and at least one second electrode 132 are provided,
The said p-semiconductor (126) is a manufacturing method of the photovoltaic element manufactured by the manufacturing method of the solid organic p-semiconductor in any one of Claims 17-19.

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