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Definitions

• a photovoltaic cell is a component in which light is converted directly into electrical energy. In addition to two electrodes, it contains at least one light-absorbing layer and one charge transport layer. If it is sunlight, one speaks of a solar cell.
• the Semiconductors are mainly used to transport electrons. No special purity and perfection of the material is necessary for this. It can e.g. B. can be simply painted from a powder suspension onto conductive glass.
• EP-A 0 333 641 describes a photoelectrochemical cell which is characterized in that it contains a nanoporous metal oxide semiconductor, ie an extremely roughened and thus enlarged surface.
• the charge transport between the semiconductor / chromophore layer and counterelectrode takes place in this cell using an electrolyte solution.
• the property profile of such a device can still be clearly improved.
• the electron has to be returned to the dye by the diffusion of ions. This means that only redox systems that are small enough to penetrate into the pores of the nanocrystalline semiconductor layer come into question.
• the invention therefore relates to a photovoltaic cell, characterized by a charge transport layer which contains a hole conductor material.
• the landing transport is no longer limited by the diffusion of the ions.
• the relevant energy levels of the layer can be adjusted so that the efficiency for sunlight can be improved to ⁇ 18%.
• FIG. 1 shows a preferred embodiment of the cell 1 according to the invention (not to scale).
• the cell according to the invention preferably contains a chromophore on the surface of the semiconductor, shown here as chromophore layer 13.
• the term light-absorbing layer encompasses both a semiconductor layer and a combination of semiconductor / chromophore, even if the actual absorption in this case takes place almost exclusively by the chromophore.
• the charge transport layer 14 which according to the invention contains a hole conductor material.
• the counterelectrode 15 can consist, for example, of a conductive glass, plastic with a conductive coating, metal or another conductive, preferably translucent material.
• the cell 1 is preferably closed at the top and bottom by an insulating layer 16 and 17, respectively. It can contain a side closure, not shown in the figure, for example a frame made of an electrically insulating material, such as plastic or glass. However, by using a hole conductor material instead of the liquid electrolyte, such a side frame is not fundamentally necessary. At least one side of the cell must be transparent to the light to be converted into electrical energy, so that it can reach the chromophore or the semiconductor.
• the cell according to the invention also contains devices, not shown in the figure, for taking off the electrical current generated by the cell.
• a hole conductor material in the sense of the invention is a material which can conduct a positive charge which is caused by the absence of an electron, mass transport and charge transport being decoupled.
• electron-rich, preferably organic compounds are suitable which are preferably reversible and can be oxidized. It is generally believed that charge transport in an organic hole conductor material occurs through the formation of radical cations.
• the oxidation potential is variable over a wide range and can be adapted to the specific energy levels of the semiconductor or sensitizer. It is preferably between the energy level of the ground state and 700, preferably 400, particularly preferably 300, mV above the ground state.
• Solid, in particular amorphous, hole conductor materials are also preferred.
• the hole conductor layer according to the invention can be prepared amorphously, i.e. is applied in the amorphous state in the photovoltaic cell according to the invention.
• Amorphous is used to describe the state of solids, the molecular building blocks of which are not arranged in crystal lattices but randomly. Unlike in a crystal, in which there is a short-range order (ie constant distances to the nearest neighboring atoms) and a long-range order (regular repetition of a base lattice) between the atoms, only a short-range order exists in the amorphous state.
• the amorphous substance has no physically excellent direction; it isotropic. Strive for all amorphous substances the crystalline state is more favorable in terms of energy. When X-rays, electron beams and neutrons are diffracted, the amorphous solid does not show any sharp interference rings like a crystal, but only diffuse interference rings at small diffraction angles (halos).
• the amorphous state is thus clearly distinguished from the crystalline, liquid or liquid-crystalline state.
• Hole conductor materials which are soluble in organic solvents and hole conductor materials which are meltable are particularly preferred.
• organic solvents but to which the invention is not restricted, are chloroform, benzene, chlorobenzene, cyclohexanone, toluene, tetrahydrofuran, anisole, cresol, xylene, methyl lactate, methylene chloride, hexane, or other aliphatic, aromatic or alcoholic solvents. It is sufficient for the production of a hole conductor layer according to the invention if the hole conductor material is soluble or meltable in an organic solvent.
• soluble means a solubility of at least 1.0 g / l at 25 ° C. in an organic or inorganic solvent, preferably in one of the solvents listed above.
• Hole conductor materials that can diffuse into the pores of a rough semiconductor layer based on their size are furthermore particularly preferred.
• the molecules of the hole transport layer have a comparable molecular dimension to the molecules of the sensitizer, if used, so that the hole conductor molecules can come into close contact with the sensitizer molecules located in the pores of the semiconductor surface.
• the hole conductor molecules are particularly preferably larger than the factor 20, very particularly preferably 10, larger than corresponding sensitizer molecules.
• the hole conductor layer generally has a thickness of 0.1 to 20 ⁇ m, preferably 1 to 15 ⁇ m.
• the charge carrier mobility of the hole conductor material is preferably at least 10 '5 cm 2 / Vs, in particular 10 "3 to 10 cm 2 / Vs.
• Spiro and hetero spiro compounds of the formula (I) are very particularly preferred as hole conductor materials
• K 1 and K 2 mean independently conjugated systems.
• Spiro compounds are compounds in which two ring systems are linked by a single, four-bonded atom. This atom is called spiro atom nd ed as in Handbook of Chemistry and Physics 62nd (1981 -2), CRC Press, pp C-23 to C-25 is executed.
• spiro compound means monomeric and polymeric carbospiro and heterospiro compounds.
• Preferred compounds of the formula (I) are 9,9'-spirobifluorene derivatives of the formula (II),
• ⁇ has the meanings given above and where the benzo groups can be independently substituted and / or fused.
• ⁇ is C, Si, Ge or Sn, preferably C, Si, Ge, particularly preferably C, Si, in particular C,
• K, L, M, N are the same or different and mean a group of the formulas
• R identical or different, has the same meanings as K, L, M, N or is hydrogen, a linear or branched alkyl, alkoxy or carboalkoxy group with 1 to 22, preferably 1 to 15, particularly preferably 1 to 12 C.
• Ar is phenyl, biphenyl, 1-naphthyl, 2-naphthyl, 2-thienyl, 2-furanyl, where each of these groups can carry one or two radicals R; m, n, p are 0, 1, 2 or 3;
• R 1 and R 2 are hydrogen, a linear or branched alkyl group with 1 to 22 carbon atoms, -Ar or 3-methylphenyl.
• Preferred compounds of the formula (III) are those of the formula (IIIa) - (IIIg)
• R C r C 2 2 alkyl, C 2 H 4 SO 3 '
• N L and is a group of the formulas:
• N L and is a group of the formulas:
• Particularly preferred compounds of the formula (III) are those of the formulas (IIlaa) to (IIldb):
• Very particularly preferred spiro compounds are those of the formula (IV)
• ⁇ is C or Si, preferably C
• K, L, M and N are identical or different one of the groups G1 to G14:
• R 5 , R 6 may also mean the same or different hydrogen or a linear or branched alkyl, alkyloxy or ester group having 1 to 22 carbon atoms, -CN or -NO 2 .
• Particularly preferred spiro compounds of the formula (IV) are 2,2 ', 4,4', 7,7 '-Hexakis (biphenylyl) -9,9' -spirobifluorene, 2,2 ', 4,4 ' , 7,7 ' -Hexakis (terphenylyl) -9.9 '-spirobifluorene, 2.2 ' , 4.4 ' -Hexakis (biphenylyl) -9.9 ' -spirobi-9-silafluorene and 2.2', 4.4 ', 7 , 7 '-Hexakis (terphenylyl) -9.9' -spirobi-9-silafluorene.
• spiro and hetero-spiro compounds used according to the invention are prepared by methods known per se, as described in EP-A 0 676 461 and standard works on organic synthesis, e.g. Houben-Weyl, Methods of Organic Chemistry, Georg-Thieme-Verlag, Stuttgart and in the corresponding volumes of the series "The Chemistry of Heterocyclic Compounds" by A. Weissberger and E. C. Taylor (editors).
• the preparation takes place under reaction conditions which are known and suitable for the reactions mentioned. Use can also be made here of variants which are known per se and are not mentioned here in detail.
• Compounds of the formula (purple) can be prepared, for example, from tetrahalogenation in positions 2, 2 ', 7, 7' of 9,9'-spirobifluorene and subsequent substitution reaction (see, for example, US Pat. No. 5,026,894) or by tetraacetylation of the positions 2, 2 ', 7, 7' 9,9'-spirobifluorene with subsequent CC linkage after conversion of the acetyl groups into aldehyde groups or heterocycle formation after conversion of the acetyl groups into carboxylic acid groups.
• Compounds of the formulas (llle) - (lllg) can be prepared, for example, by choosing suitably substituted starting compounds when constructing spirobifluorene, e.g. 2,7-dibromo-spirobifluorene can be constructed from 2,7-dibromo-fluorenone and 2,7-dicarbethoxy-9,9'-spirobifluorene by using 2,7-dicarbethoxy-fluorenone. The free 2 ', 7' positions of the spirobifluorene can then be independently substituted further.
• 2,7-dibromo-spirobifluorene can be constructed from 2,7-dibromo-fluorenone and 2,7-dicarbethoxy-9,9'-spirobifluorene by using 2,7-dicarbethoxy-fluorenone.
• the free 2 ', 7' positions of the spirobifluorene can then be independently substituted further.
• disubstituted pyridines disubstituted pyrazines, disubstituted pyrimidines and disubstituted pyridazines
• disubstituted pyridines disubstituted pyrazines, disubstituted pyrimidines and disubstituted pyridazines
• disubstituted pyridines disubstituted pyrazines
• disubstituted pyrimidines disubstituted pyrimidines
• disubstituted pyridazines disubstitutedazines
• Heterospiro compounds of the formula (purple) can be produced, for example, starting from tetrahalogenation in positions 2, 2 ', 7, 7' of the 9,9'-spirobi-9-silafluorene and subsequent substitution reaction, which is known from analogous C-spiro compounds (see, for example, US Pat. No. 5,026,894) or via a tetraacetylation of positions 2, 2 ', 7, 7' of the 9.9'-spirobi-9-silafluorene with subsequent CC linkage after conversion of the acetyl groups into aldehyde groups or
• Carboxylic acid groups take place.
• Compounds of the formula (IIIc) can be prepared, for example, by dibromination in the 2,2'-position with subsequent diacetylation in the 7,7'-position of the 9,9'-spirobi-9-silafluorene and subsequent reaction analogously to that of the compounds (purple).
• the photovoltaic cell according to the invention contains as light-absorbing Layer preferably a semiconductor, which preferably has a very large band gap, particularly preferably at least 3.0 eV, very particularly preferably above 3.0 eV.
• Metal oxide semiconductors in particular the oxides of the transition metals, and of the elements of the third main group and the fourth, fifth and sixth subgroup (of the periodic system of the elements) of titanium, zirconium, hafnium, strontium, zinc, indium, yttrium, are therefore preferably suitable.
• any other metal oxide with semiconductor properties and a large energy gap (band gap) between the valence band and the conduction band can also be used. Titanium dioxide is particularly preferred as the semiconductor material.
• the semiconductor preferably has a roughness factor of greater than 1, particularly preferably greater than 20, very particularly greater than 150.
• the roughness factor is defined as the ratio of a real / effective one
• the roughness factor can e.g. determined by gravimetric adsorption methods, e.g. in F. Kohlrausch, Practical Physics, Volume 1, p. 397 (Stuttgart: B.G. Teubner, 1 985).
• the size of the pores is 5-200 nm, preferably 10-50 nm.
• a method for producing polycrystalline metal oxide semiconductor layers using the SOL-GEL method (described in detail, for example, in Stalder and Augustynski, J. Electrochem. Soc. 1979, 1 26, 2007), where in the method step the hydrolysis of the metal -Alcoholate the percentage relative Humidity of the ambient atmosphere can be in a range from 30% to 80% and is kept constant within ⁇ 5%, preferably ⁇ 1%, results in metal oxide semiconductor layers with which a particularly high electrical yield can be achieved in photovoltaic cells according to the invention.
• the rough surface with a polycrystalline structure offers an area which is larger by the roughness factor for a, preferably, monomolecular surface layer of the chromophore. This ensures that the light incident on an area of a certain size is converted into electrical energy with a significantly higher yield.
• the semiconductor can be considered to be transparent to the incident luminous flux. However, light is partially reflected on the surface and reaches e.g. T. on neighboring surfaces. The penetrating into the semiconductor and not absorbed or converted light hits z. T. directly and partly indirectly and partly indirectly, after total reflection on the surface on the exit side of chromophore molecules, which makes it possible to achieve a significantly higher luminous efficiency.
• the SOL-GEL process is described below as an example.
• the titanium substrate of pure titanium of approximately 99.5% purity is first cleaned in approximately 18% boiling HCl for approximately 30 minutes.
• the titanium ethoxide solution can e.g. B. can be obtained by dissolving 21 mmol of TiCl 4 in 10 ml of very pure ethanol (puriss.). This solution is then diluted with very pure methanol (puriss.) In order to obtain a titanium concentration in the range of approximately 25 to 50 mg / ml.
• a drop of the solution is added to the titanium substrate and the titanium alkoxide is hydrolyzed at room temperature for about 30 minutes at a humidity of 48 ⁇ 1%.
• the substrate with the hydrolyzed layer is then heated to about 450 ° C. for about 15 minutes. This process is repeated several times.
• the TiO 2 layer After 10 to 1 5 Repeated repetition, the TiO 2 layer has reached a thickness of approximately 20 ⁇ m.
• the substrate with the layer is then baked at about 500 ° C. for about 30 minutes in a pure argon atmosphere (for example 99.997%).
• the TiO 2 layer produced in this way has a roughness factor in the range of 200.
• Metal oxide semiconductor layers of this type can be produced on other substrates using analog processes.
• the upper layers of the semiconductor can optionally, such as. B. described in WO-A 91/1 6719, doped with a divalent or trivalent metal.
• the sensitivity that is to say the photoelectronic yield for visible light, that is to say also for sunlight, can be increased by so-called chromophores, also called sensitizers or dyes, being chemically attached or incorporated (chemisorbed) as charge carriers on the surface of the semiconductor.
• chromophores also called sensitizers or dyes
• the two functions of light absorption and charge carrier separation are separated in these photoelectronic systems.
• the light absorption is taken over by the chromophore in the surface area, and the charge carriers are separated at the semiconductor / chromophore interface.
• Different chromophores have different spectral sensitivities. The choice of the chromophore can thus be adapted to the spectral composition of the light from the light source in order to increase the yield as much as possible.
• the complexes of transition metals of the metal (L 3 ), metal (L 2 ) type of ruthenium and osmium are particularly suitable as chromophores, ie sensitizers.
• Ruthenium eis diaqua bipyridyl complexes such as ruthenium cis-diaqua bis (2,2 ' bipyridyl-4,4' dicarboxylate) as well as porphyrins (e.g. zinc tetra (4-carboxyphenyl) porphyrin) and cyanides (e.g. iron -Hexacyanide complexes) and phthalocyanines.
• the chromophores can be chemisorbed, adsorbed or otherwise firmly attached in the area of the surface of the metal oxide semiconductor.
• Favorable results have been achieved, for example, with chromophores, with carboxylic acid or Phosphonic acid ligands are bound to the surface of the metal oxide semiconductor.
• Suitable chromophores are also described, for example, in Chem. Rev. 1995, 49-68.
• Chromophores (VIII) and (IX) are particularly preferred,
• chromophore for example RuL 3 4 '
• the application of the chromophore takes place, for. B. by immersing the substrate with the oxide layer in an ethanolic solution of 2 x 10 "4 M RuL 3 4" , for about an hour.
• Other chromophores can be applied to titanium oxide or other metal oxide semiconductors using analog processes.
• Stable, metallically conductive substances for. B. Au, Ag, Pt, Cu, or other metals. But it can also, for some applications preferably translucent conductive substances such as doped metal oxides, for. B. indium tin oxide, Sb-doped tin oxide or Al-doped zinc oxide can be used.
• the work function of the electrode material used can preferably be adapted to the ionization potential of the hole transport material used.
• the electrode can, as described in EP-A 0 333 641, on a transparent substrate, e.g. B. glass can be applied and connected to the hole transport layer.
• a transparent substrate e.g. B. glass
• it can be in the cell described in this invention by physical deposition methods, e.g. B. vapor deposition or atomization (sputtering) can be applied directly to the hole transport layer without the need for a second glass plate. This method is preferred in applications where the weight of the cell is to be reduced.
• the electrode can also be coated with a further semiconductor, as described in WO-A 93/19479.
• Plastic or glass are suitable as electrically insulating materials 1 6 and 1 7 or optionally as a lateral frame for the cell according to the invention.
• the invention therefore also relates to a method for producing a photovoltaic cell, characterized in that it is based on a conductive solid carrier a) applies a semiconductor colloid, b) optionally applies a dye thereon, c) applies a transport layer containing a hole conductor material thereon, d) applies the counterelectrode thereon, and e) applies an insulating layer.
• the cell can e.g. B. sealed with an adhesive or a film.
• the photovoltaic cell according to the invention generally has a thickness of 5 to 20 mm (with substrate).
• it can be provided with a one, two or more layers of anti-reflective coating.
• the back of the cell can be constructed so that light is diffusely reflected back into the cell.
• a further increase in the luminous efficacy can be achieved, for example, by concentrating the incident sunlight, for example by means of mirrors or Fresnel lenses.
• the cell according to the invention can also be part of a tandem cell; in such devices, several sub-cells convert light from different spectral ranges into electrical energy.
• the cell according to the invention is used as a photocell, ie it is used to generate electrical energy from light. It is preferably a solar cell, i. H. a device for generating electrical energy from sunlight.
• a photocell ie it is used to generate electrical energy from light.
• It is preferably a solar cell, i. H. a device for generating electrical energy from sunlight.
• Compound 1 described in Example 3 was dissolved in tetrahydrofuran at a concentration of 50 g / l.
• a substrate was coated, which consisted of conductive, SnO 2 -coated glass, on one side of which a smooth layer of Nb-doped titanium dioxide had been applied (substrate I). Both sides of the substrate were coated by an immersion process.
• a thin layer of gold was then deposited on the side coated with titanium dioxide by thermal evaporation.
• the side coated with titanium dioxide and gold is hereinafter referred to as the active side, the other as the inactive side.
• the sample prepared in this way was mounted in an optical setup consisting of a high-pressure lamp, optical filters, lenses and holders.
• the intensity could be varied by using filters and moving the lenses.
• the light with a wavelength below 380 nm was essentially filtered out in order to prevent direct excitation of compound 1 by light.
• the sample was mounted with the inactive side facing the lamp so that the residual light in the region of the absorption spectrum of compound 1 was absorbed by the layer on the inactive side. Due to the doping with Nb, the titanium dioxide layer had a low absorption between 400 and 450 nm, so that this was excited by the lamp.
• the gold and SnO 2 layers were contacted and connected to an ammeter while the sample was exposed. No external voltage was applied. A current was observed during the exposure of the sample, which disappeared after the light source was dimmed. When compared to a thermal treatment of the sample, it was shown that the current observed was a real photocurrent which is generated by injecting positive charge carriers (holes) into the layer of compound 1 and transporting the holes through this layer. The intensity of the exposure was varied by a factor of ten; Over this range the photocurrent grew linearly with the intensity.
• Compound 1 was dissolved in tetrahydrofuran at a concentration of 50 g / l.
• a substrate was coated, which consisted of conductive, SnO 2 -coated glass, on which a nanoporous layer of titanium dioxide had been applied on one side, the proportion of the rutile phase still weakly absorbing above 400 nm being about 30% and the surface had a roughness factor of 700-1000 (substrate II). Both sides of the substrate were coated by an immersion process.
• a thin layer of gold was then applied to the side coated with titanium dioxide by thermal vapor deposition.
• the side coated with titanium dioxide and gold is hereinafter referred to as the active side, the other as the inactive side.
• the sample thus prepared was mounted in the optical setup described in Example 7.
• the sample was mounted with the inactive side facing the lamp so that the residual light in the range of the absorption spectrum of compound 1 was absorbed by the layer on the inactive side. Due to the proportion of the rutile phase, the titanium dioxide layer had a low absorption between 400 and 430 nm, so that this was excited by the lamp.
• the gold and SnO 2 layers were contacted and connected to an ammeter while the sample was exposed. No external voltage was applied. A current was observed during the exposure of the sample, which disappeared after the light source was dimmed. When the thermal treatment of the sample was compared, it was found that the current observed was a real photocurrent which is produced by injecting positive charge carriers (holes) into the layer from compound 1 and transporting the holes through this layer. The intensity of the exposure was varied by a factor of ten; Over this range the photocurrent grew linearly with the intensity. The photocurrent was many times over higher than the photocurrent of the sample described in Example 7, which indicates that compound 1 penetrates into the pores of the layer (see FIG. 2).
• Example 7 The sample described in Example 7 was mounted in an optical setup consisting of a pulsed, tunable laser, a white light source, a monochromator and imaging and detection optics.
• the laser delivered pulses at 30 Hz with a duration of approx. 2 ns at 420 nm, i.e. H. outside the absorption of compound 1, but still within the absorption of the Nb-doped titanium dioxide layer. While the sample was so irradiated, the transient absorption of the radical cation of Compound 1 was observed at 500 nm. The increase in absorption took place within the time resolution of the experiment. This indicates a very effective and rapid injection of the charge carriers into the layer from compound 1.
• a nanoporous layer of TiO 2 was applied to a SnO 2 -coated glass support by screen printing with a suspension produced by the sol-gel method and dried in a hot air stream at approx. 400 ° C. for approx. 20 minutes.
• the layer thickness is approx. 1.5 ⁇ m, the layer consists almost entirely of the anatase phase and therefore has no absorption above 400 nm.
• the coated support was immersed in a 10 "4 M ethanolic solution of ruthenium tris (2,2'-bipyridyl-4,4'-dicarboxylate) at a temperature of about 50 ° C. After about 2 hours, the support was removed removed from the solution, rinsed with ethanol and briefly dried in a warm air stream.
• the layer system had a maximum absorbance of approximately 0.2 at approximately 500 nm.
• the area of the sample was approximately 0.3 cm 2 .
• the sample thus prepared was assembled in the setup described in Example 7.
• the light with a wavelength below 430 nm was blocked by using appropriate optical filters.
• the structure was adjusted so that the intensity of the radiation corresponded approximately to the intensity of sunlight in Central Europe (approx. 750 W / m 2 ).
• the gold and SnO 2 layers were contacted and connected to a potentiostat while the sample was exposed. Without external voltage, the sample showed a current of approx. 200 nA when exposed, but without exposure, however, no current. If an edge filter was installed at 470 nm, the decrease in photocurrent corresponded approximately to the decrease in light absorption by the dye (see FIG. 3).
• the current-voltage characteristics of the sample were measured with and without exposure. Without exposure, no more measurable current flowed, even when external voltage was applied.
• the characteristics of a photovoltaic cell with an open-circuit voltage of approx. 500-600 mV and a short-circuit current of approx. 800 nA / cm 2 were measured under exposure (see FIG. 4).
• a nanoporous layer was made from a SnO 2 -coated glass substrate
• TiO 2 by screen printing using a sol-gel method Suspension applied and dried in a hot air stream at about 400 ° C for about 20 minutes.
• the layer thickness is approx. 1.5 ⁇ m, the layer consists almost entirely of the anatase phase and therefore has no absorption above 400 nm.
• the coated support was immersed in a 10 "4 M ethanolic solution of ruthenium tris (2,2'-bipyridyl-4,4'-dicarboxylate) at a temperature of about 50 ° C. After about 2 hours, the support was removed removed from the solution, rinsed with ethanol and briefly dried in a warm air stream.
• the layer system had a maximum absorbance of approximately 0.2 at approximately 500 nm.
• the area of the sample was approximately 0.3 cm 2 .
• the sample thus prepared was assembled in the setup described in Example 7.
• the light with a wavelength below 430 nm was blocked by using appropriate optical filters.
• the structure was adjusted so that the intensity of the radiation corresponded approximately to the intensity of sunlight in Central Europe (approx. 750 W / m 2 ).
• the gold and SnO 2 layers were contacted and connected to a potentiostat while the sample was exposed. Without an external voltage, the sample showed a current of approx. 7 ⁇ A when exposed, but no current without exposure.
• the current-voltage characteristics of the sample were measured with and without exposure. Without exposure, no more measurable current flowed, even when external voltage was applied.
• the characteristics of a photovoltaic cell with an open circuit voltage of approx. 500 mV and a short circuit current of approx. 14 ⁇ A / cm 2 were measured under exposure.

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• 1995
  • 1995-09-13 DE DE19533850A patent/DE19533850A1/de not_active Withdrawn
• 1996
  • 1996-09-09 JP JP51164197A patent/JP4121148B2/ja not_active Expired - Fee Related
  • 1996-09-09 EP EP96931054A patent/EP0850492B1/de not_active Expired - Lifetime
  • 1996-09-09 DE DE59610223T patent/DE59610223D1/de not_active Expired - Lifetime
  • 1996-09-09 CN CN96196958A patent/CN1126184C/zh not_active Expired - Lifetime
  • 1996-09-09 WO PCT/EP1996/003944 patent/WO1997010617A1/de not_active Ceased
  • 1996-09-09 AU AU69885/96A patent/AU708210B2/en not_active Expired
  • 1996-09-11 US US08/712,426 patent/US5885368A/en not_active Expired - Lifetime

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