Classifications

• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
  • H10K85/00—Organic materials used in the body or electrodes of devices covered by this subclass
  • H10K85/50—Organic perovskites; Hybrid organic-inorganic perovskites [HOIP], e.g. CH3NH3PbI3
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
  • H10K30/00—Organic devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation
  • H10K30/40—Organic devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation comprising a p-i-n structure, e.g. having a perovskite absorber between p-type and n-type charge transport layers
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
  • H10K30/00—Organic devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation
  • H10K30/10—Organic devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation comprising heterojunctions between organic semiconductors and inorganic semiconductors
  • H10K30/15—Sensitised wide-bandgap semiconductor devices, e.g. dye-sensitised TiO2
  • H10K30/151—Sensitised wide-bandgap semiconductor devices, e.g. dye-sensitised TiO2 the wide bandgap semiconductor comprising titanium oxide, e.g. TiO2
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
  • H10K30/00—Organic devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation
  • H10K30/10—Organic devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation comprising heterojunctions between organic semiconductors and inorganic semiconductors
  • H10K30/15—Sensitised wide-bandgap semiconductor devices, e.g. dye-sensitised TiO2
  • H10K30/152—Sensitised wide-bandgap semiconductor devices, e.g. dye-sensitised TiO2 the wide bandgap semiconductor comprising zinc oxide, e.g. ZnO
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
  • H10K30/00—Organic devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation
  • H10K30/50—Photovoltaic [PV] devices
  • H10K30/57—Photovoltaic [PV] devices comprising multiple junctions, e.g. tandem PV cells
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E10/00—Energy generation through renewable energy sources
  • Y02E10/50—Photovoltaic [PV] energy
  • Y02E10/548—Amorphous silicon PV cells
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E10/00—Energy generation through renewable energy sources
  • Y02E10/50—Photovoltaic [PV] energy
  • Y02E10/549—Organic PV cells

Definitions

• the present invention relates to the field of photovoltaic devices, in particular photovoltaic cells of the perovskite type. It aims more particularly to propose the formulation of a new conductive layer of type N in the multilayer stacks useful for forming these photovoltaic devices, making it possible to achieve improved performance in terms of photovoltaic conversion efficiency.
• Photovoltaic devices and in particular photovoltaic cells, comprise a multilayer stack comprising a photoactive layer, called an “active” layer.
• This active layer is in contact on both sides with an N-type conductive layer and a P-type conductive layer.
• This type of multilayer assembly comprising the superposition of the active layer and the two P-type layers and of type N described above is conventionally called “NIP” or “PIN” according to the order of stacking of the different layers on the substrate.
• the active layer consists of a halogenated perovskite-type material, which may be hybrid organic-inorganic or purely inorganic.
• a perovskite-type photovoltaic cell of NIP structure comprises a multilayer structure typically comprising, in this stacking order, a transparent substrate, a first transparent electrode also called a lower electrode, an N-type conductive layer, an active layer of perovskite type, a P-type conductive layer and a second electrode, also called an upper electrode made of metal, for example silver or gold.
• the N-type conductive layer usually consists of an N-type semiconductor oxide, for example ZnO, AZO (zinc oxide doped with aluminum), SnCh or TiO x (x ⁇ 2).
• This layer can be in the so-called mesoporous or planar form.
• the P-type conductive layer for its part consists, in the majority of cases, of an organic semiconductor material which can be a p-conjugated polymer, such as, for example, poly (3-hexylthiophene) or P3HT.
• the best photovoltaic performances are obtained with devices for which a dense conductive layer based on N-type metal oxide (s) is obtained after a heat treatment at high temperature. , typically at temperatures strictly above 200 ° C.
• Such high temperature heat treatments are for example implemented for the preparation of photovoltaic cells where the N layer is formed from a titanium oxide in mesoporous form. This is also the case for the production of N-type layers by the sol-gel route, in particular based on tin oxide (SnC) generated from an SnCT precursor.
• SnC tin oxide
• an alternative to prepare a conductive layer of type N at low temperature for a photovoltaic cell in NIP structure, without impacting on the photovoltaic efficiency of the cell consists in adding a layer of fullerene, for example in PCBM, between the N-type metal oxide and the overlying active layer of perovskite, to facilitate charge extraction.
• a layer of fullerene for example in PCBM
• the thickness of the deposited fullerene layer must be extremely small, typically of the order of a few nanometers.
• the present invention aims specifically to provide a new method of preparing, at low temperature, a conductive layer based on conductive oxide (s) of type N in a multilayer stack useful for photovoltaic devices of the perovskite type, making it possible to achieve excellent performance, in particular in terms of photovoltaic performance.
• photovoltaic devices in particular photovoltaic cells of the perovskite type, exhibiting excellent performance, from a multilayer stack incorporating an oxide-based layer (s ) N-type metal (s), prepared at low temperature, subject to controlling the atomic concentration of carbon in said N layer.
• the present invention relates, according to a first of its aspects, to a multilayer stack useful for forming a photovoltaic device, said stack comprising at least:
• N-type conductive layer also called an "electron transport layer"
• a P-type conductive layer also called a “hole transport layer”
• photo-active layer an active layer from the photovoltaic point of view, called “photo-active layer” or “active layer”, of perovskite type, interposed between said conductive layers of type N and of type P, in which said conductive layer of type N is at based on individualized nanoparticles of N-type metal oxide (s), and has a carbon content of less than or equal to 20 atomic%.
• a multilayer stack according to the invention may have a PIN or PIN structure, preferably a PIN structure.
• Such a multilayer stack of NIP structure according to the invention can more particularly comprise, in this order of superposition, at least:
• a substrate in particular transparent, flexible or rigid, such as a substrate made of glass or of plastic, for example of PET;
• a first electrode, called the lower electrode in particular formed of a transparent conductive layer, in particular of transparent conductive oxide (s);
• N-type conductive layer as defined above, in the case of a NIP structure, or a P-type conductive layer in the case of a PIN structure;
• the upper electrode a second electrode, called the upper electrode.
• the invention also relates to a process for preparing such a multilayer stack, comprising at least one step of forming said N-type conductive layer, from a dispersion of nanoparticles of metal oxide (s) of type N in a solvent medium, at a temperature less than or equal to 150 ° C, and under operating conditions adjusted to obtain the desired carbon content in said N layer.
• a process for preparing such a multilayer stack comprising at least one step of forming said N-type conductive layer, from a dispersion of nanoparticles of metal oxide (s) of type N in a solvent medium, at a temperature less than or equal to 150 ° C, and under operating conditions adjusted to obtain the desired carbon content in said N layer.
• the control of the carbon content in the N-type layer, formed under conditions of low temperature makes it possible to access devices exhibiting excellent photovoltaic performance, in particular in terms of efficiency of photo voltaic conversion.
• the carbon content in the N-type layer formed according to the invention can be adjusted by implementing a dispersion of nanoparticles of metal oxide (s). ) exhibiting a reduced content of carbon precursor compounds, such as to make it possible to produce the desired carbon content, less than or equal to 20 atomic%, in the N layer formed.
• a dispersion of nanoparticles of metal oxide (s). ) exhibiting a reduced content of carbon precursor compounds, such as to make it possible to produce the desired carbon content, less than or equal to 20 atomic%, in the N layer formed.
• Such dispersions of nanoparticles of metal oxide (s) are, for example, dispersions stabilized via the surface potential of the nanoparticles and having a reduced content of compatibilizing agents.
• the carbon content in the N-type layer formed according to the invention can be adjusted by subjecting, after deposition of said dispersion of nanoparticles of metal oxide (s) and prior to the deposition of the overlying layer, the N-type layer, to a treatment for removing carbon, in particular by treatment by UV irradiation, by UV-ozone, with ozone and / or by plasma, in particular oxidizing.
• a treatment for removing carbon in particular by treatment by UV irradiation, by UV-ozone, with ozone and / or by plasma, in particular oxidizing.
• the low temperature conditions preferably less than or equal to 120 ° C, advantageously less than or equal to 100 ° C, in particular less than or equal to 80 ° C and more particularly less than or equal to 50 ° C, allow the formation of the N layer in stacks of various kinds, in particular at the surface of structures sensitive to high temperatures, for example structures incorporating plastic substrates such as PET.
• the process for preparing an N layer according to the invention at low temperature makes it possible to envisage its formation on the surface of an active layer of perovskite type in the case of a stack in the PIN structure.
• a multilayer stack according to the invention can be intended for perovskite photovoltaic devices, in particular single-junction photovoltaic cells, in a structure known as of the “PIN” or “NIP” type, or else photovoltaic cells of. multi-junction type, in particular tandem type.
• the invention thus relates, according to another of its aspects, to a photovoltaic device, in particular a photovoltaic cell of the perovskite type, comprising a multilayer stack as defined above or obtained by a method as defined above.
• FIG 1 shows, schematically, in a vertical sectional plane, multilayer stacks according to the invention, of NIP structure (21) or PIN structure (22).
• FIG 2 shows the change in the carbon atomic concentration in an N layer based on AZO nanoparticles as a function of the duration of the UV-ozone treatment, under the conditions of Example 2.
• the invention relates, according to a first of its aspects, to a multilayer stack, useful for forming a photovoltaic device, said stack comprising at least:
• active layer a photovoltaic active layer, called “active layer”, of perovskite type, interposed between said conductive layers of N type and of P type, in which said N type conductive layer is based on individualized nanoparticles of metal oxide (s) (s) of type N, and has a carbon content of less than or equal to 20 atomic%.
• N layer An N-type conductive layer according to the invention is more simply referred to in the remainder of the text as "N layer”.
• N-type material designates a material which allows the transport of electrons (e).
• the N layer according to the invention can be more particularly formed of individualized nanoparticles of N-type metal oxide (s).
• the N-type metal oxide nanoparticles can in particular be chosen from nanoparticles of zinc oxide ZnO, titanium oxides TiO x with x between 1 and 2, tin oxide (SnC), doped zinc oxides, e.g. aluminum doped zinc oxide (AZO), indium doped zinc oxide (IZO), gallium doped zinc oxide (GZO), oxides titanium doped, for example titanium oxide doped with nitrogen, phosphorus, iron, tungsten or manganese, and mixtures thereof.
• ZnO zinc oxide
• SnC tin oxide
• doped zinc oxides e.g. aluminum doped zinc oxide (AZO), indium doped zinc oxide (IZO), gallium doped zinc oxide (GZO)
• oxides titanium doped for example titanium oxide doped with nitrogen, phosphorus, iron, tungsten or manganese, and mixtures thereof.
• the N-type conductive layer according to the invention can be formed from nanoparticles of metal oxide (s) chosen from nanoparticles of tin oxide. (S11O2), nanoparticles of doped zinc oxide, in particular zinc oxide doped with aluminum (AZO), and mixtures thereof.
• s metal oxide
• S11O2 nanoparticles of tin oxide.
• AZO zinc oxide doped with aluminum
• the individualized particles of N-type metal oxide (s) of the N-type conductive layer in a multilayer stack according to the invention may have an average particle size of between 2 to 100 nm, in particular between 5 to 50 nm, in particular between 5 and 20 nm and more particularly between 8 and 15 nm.
• Particle size can be assessed by transmission electron microscopy.
• the average particle size refers to the diameter of the particle. If the particles are irregularly shaped, the particle size refers to the equivalent diameter of the particle. By equivalent diameter is meant the diameter of a spherical particle that exhibits the same physical property when determining the particle size as the irregularly shaped particle measured.
• the nanoparticles of N-type metal oxide (s) can in particular be of spherical shape.
• spherical particle is meant particles having the shape or substantially the shape of a sphere.
• spherical particles have a coefficient of sphericity greater than or equal to 0.75, in particular greater than or equal to 0.8, in particular greater than or equal to 0.9 and more particularly greater than or equal to 0.95.
• the coefficient of sphericity of a particle is the ratio of the smallest diameter of the particle to the largest diameter of the particle. For a perfect sphere, this ratio is equal to 1.
• individualized nanoparticles is meant that the particles retain their state of individual particles within the N layer of the multilayer stack according to the invention, in particular that they are not fused.
• less than 10% of the nanoparticles of N-type metal oxide (s) in said N layer are fused, preferably less than 5%, or even less than 1%.
• N layer based on individualized N-type metal oxide (s) nanoparticles is distinguished in particular from sintered layers, in which the particles have fused to each other.
• An N layer according to the invention is thus an unsintered layer.
• the structuring of the N-type layer in a stack according to the invention testifies in particular to the fact that its preparation, as detailed in the remainder of the text, does not involve any step of heat treatment at high temperature, typically at a strictly higher temperature. at 150 ° C, especially above 200 ° C.
• N-type metal oxide (s) particles in other words non-fused, at the N-type layer according to the invention can also be manifested by a surface roughness of said layer of type. N, measured before formation of the overlying layer, greater than that obtained for example for a sintered layer.
• an N layer according to the invention may have an average RMS roughness value greater than or equal to 3 nm, in particular between 5 and 10 nm.
• Surface roughness can be measured by mechanical profilometry.
• An N-type conductive layer according to the invention is also characterized by a low carbon content (atomic carbon concentration), in particular less than or equal to 20 atomic%.
• an N layer according to the invention has a carbon content of less than or equal to 17 atomic%, preferably less than or equal to 15 atomic%, in particular between 0 and 15 atomic%.
• the carbon content of an N layer according to the invention can be determined by X-ray induced photoelectron spectrometry (XPS for "X-Ray photoelectron spectrometry").
• An N-type conductive layer according to the invention may have a thickness of between 10 and 80 nm, in particular between 30 and 50 nm.
• the thickness can be measured with a profilometer, for example of the trade name KLA Tencor or else with an AFM atomic force microscope, for example of the trade name VEECO / INNOVA.
• a profilometer for example of the trade name KLA Tencor or else with an AFM atomic force microscope, for example of the trade name VEECO / INNOVA.
• Other layers of the multilayer stack are possible.
• a multilayer stack according to the invention comprises at least one active photovoltaic layer of perovskite type.
• This active layer is formed from a perovskite material, and more particularly a material of general formula ABX3, with:
• B representing one or more metallic elements, such as lead (Pb), tin (Sn), bismuth (Bi) and antimony (Sb); and
• X representing one or more anions, in particular one or more halogens, and more particularly chosen from chlorine, bromine, iodine and mixtures thereof.
• perovskite materials are described in particular in document WO 2015/080990.
• perovskite materials mention may in particular be made of organic-inorganic hybrid perovskites.
• These hybrid perovskite materials can be more particularly of the abovementioned formula ABX3, in which A comprises one or more organic or non-organic cations.
• the organic cation can be chosen from organo-ammonium cations such as:
• the organic cation (s) of the hybrid perovskite material may optionally be combined with one or more metal cations, for example cesium and / or rubidium.
• organo-ammonium cation for example of methylammonium (MA) type, a formamidinium (FA) cation or a mixture of these two cations, optionally combined with cesium;
• MA methylammonium
• FA formamidinium
• the perovskite material can in particular be CH3NH3PM3, also called PK, with the lead being able to be replaced by tin or germanium and the iodine being able to be replaced by chlorine or bromine.
• the perovskite material may also be a compound of the formula Cs x FAI-x Pb (II Br y y) 3 with x ⁇ 0.17; 0 ⁇ y ⁇ 1 and FA symbolizing the formamidinium cation.
• a “type P” material designates a material allowing the transport of holes (h + ).
• the P-type material can be chosen, for example, from Nafion, WO3, M0O3, V2O5 and NiO, p-conjugated semiconductor polymers, optionally doped, and mixtures thereof.
• p-conjugated semiconductor polymers optionally doped, mention may in particular be made of poly (3,4-ethylenedioxythiophene) (PEDOT), preferably PEDOT: PSS; poly (3-hexylthiophene) or P3HT, poly [N-9'-heptadecanyl-2,7-carbazole-alt-5,5- (4,7-di-2-thienyl-2 ', l', 3 '-benzothiadiazole or PCDTBT, poly [2, l, 3-benzothiadiazole-4,7-diyl [4,4-bis (2-ethylhexyl) -4H-cyclopenta [2, lb: 3,4-b'] dithiophene -
• PEDOT poly (3,
• a preferred P-type material is a mixture of PEDOT and PSS, or alternatively PT AA, optionally doped with a lithium salt.
• the P-type material can also be chosen from P-type semiconductor molecules such as:
• triphenylamine nucleus TPA
• a multilayer stack according to the invention may be intended for a photovoltaic device, in particular a perovskite photovoltaic cell, in a PIN or NIP type structure, or else of the tandem type.
• the “PIN” or “PIN” structure reflects the order of superposition of the different layers in the multilayer stack.
• the multilayer stack according to the invention is in a so-called NIP structure.
• Such a stack comprises, in this order of superposition:
• a multilayer stack according to the invention comprises, in this order of superposition, the following layers:
• a stack according to the invention in particular intended for a photovoltaic cell, of the perovskite type, in the NIP or PIN structure, may more particularly include, as shown in FIG. 1, in this order of superposition at least:
• a substrate 11 in particular transparent, flexible or rigid, such as a substrate made of glass or of plastic, in particular of PET;
• a multilayer stack according to the invention is intended for a photovoltaic device, in particular a photovoltaic cell, of the perovskite type in NIP structure.
• a multilayer stack in NIP structure according to the invention 21 more particularly comprises, in this order of superposition, at least:
• a multilayer stack according to the invention may be intended for a photovoltaic cell of the multi-junction type, and in particular of the “tandem” or double-junction type, of which at least one of the active layers is in perovskite material.
• tandem-type cells have two multilayer assemblies stacked on top of each other, and the respective active layers of which generally exhibit different light absorption spectra.
• photons not absorbed by the first active layer may be absorbed by the second.
• the quantity of photons recovered by all the active layers of the cell is thus increased and the electrical efficiency of the latter is improved.
• a tandem type photovoltaic device may include a stack according to the invention, in a PIN or PIN structure, preferably in a PIN structure, as described above.
• It may be, for example, a perovskite silicon tandem cell.
• glass or plastic in particular polyester, preferably polyethylene terephthalate (PET), polyethylene naphthalate (PEN) or polycarbonates. It may in particular be a glass plate.
• the lower electrode 12, in contact with the support, may be formed of a transparent conductive layer, for example of transparent conductive oxide (s) (TCO) such as indium oxide doped with l 'tin (ITO), zinc oxide doped with aluminum (AZO), zinc oxide doped with gallium (GZO), zinc oxide doped with indium (IZO) and mixtures thereof, or still be formed of a multilayer assembly, for example AZO / Ag / AZO.
• TCO transparent conductive oxide
• ITO indium oxide doped with l 'tin
• AZO zinc oxide doped with aluminum
• GZO zinc oxide doped with gallium
• IZO zinc oxide doped with indium
• It can also be formed by an array of nanowires, in particular made of silver.
• the upper electrode 16 can, for example, be formed by a layer of gold, of silver, or of an array of nanowires, preferably of silver. It can also be in aluminum or in transparent conductive oxide.
• the process for preparing a stack according to the invention comprises at least one step of forming an N-type conductive layer according to the invention, at low temperature, in particular at a temperature less than or equal to 150 ° C, preferably less than or equal to 100 ° C and more preferably less than or equal to 80 ° C, from a dispersion of nanoparticles of N-type metal oxide (s) in a solvent medium and in operating conditions adjusted to obtain the desired reduced carbon content in the N layer formed.
• a temperature less than or equal to 150 ° C preferably less than or equal to 100 ° C and more preferably less than or equal to 80 ° C
• Said N-type conductive layer can advantageously be formed under temperature conditions less than or equal to 120 ° C, in particular less than or equal to 100 ° C, in particular less than or equal to 80 ° C, preferably less than or equal to 50 ° C, and more particularly at room temperature
• the N-type layer according to the invention is formed on the surface of the lower electrode or, alternatively, on the surface of an active layer of perovskite type, as described above.
• the method according to the invention can more particularly comprise at least the steps consisting in:
• step (c) successively forming, on the surface of said N-type conductive layer 13 formed at the end of step (b), in this order of superposition: an active layer 14 of perovskite type, a conductive layer 15 of the type P and a second electrode 16, called the upper electrode, in particular as defined above.
• the formation of said N-type layer by the solvent route according to the invention involves the deposition of said dispersion of nanoparticles of metal oxide (s), followed by the elimination of said solvent or solvents.
• the dispersion can be deposited by means of any technique known to those skilled in the art, for example chosen from spin coating or centrifugal coating (“spin coating”), deposition with a scraper, blade coating, ultrasonic spray deposition, G slot-die coating, inkjet printing, gravure printing, flexography and screen printing.
• spin coating spin coating
• the deposition is carried out by spin-coating.
• the solvent medium for said dispersion of nanoparticles of metal oxide (s) can comprise one or more solvents chosen from polar solvents, such as water and / or alcohols, or of ether type (for example alkyl ethers and glycol ethers) or esters (acetate, benzoate or lactones for example). It may for example consist of water and / or an alcohol, such as butanol.
• polar solvents such as water and / or alcohols
• ether type for example alkyl ethers and glycol ethers
• esters acetate, benzoate or lactones for example
• It may for example consist of water and / or an alcohol, such as butanol.
• the nature of the solvent (s) is chosen with regard to the nature of the underlying layer on the surface of which said N-type conductive layer is formed.
• the removal of said solvent (s) is carried out under temperature conditions less than or equal to 150 ° C, in particular less than or equal to 120 ° C, preferably less than or equal to 100 ° C and more preferably less than or equal to 80 ° C.
• the drying of the N layer can for example be carried out at room temperature.
• ambient temperature is meant a temperature of 20 ° C ⁇ 5 ° C.
• the level of carbon in the N-type conductive layer is adjusted by controlling the content of carbon precursor compounds in the dispersion of nanoparticles of metal oxide (s) used.
• the N-type layer according to the invention can be formed by depositing a dispersion of nanoparticles of metal oxide (s) having a content of carbon precursor compounds such that the resulting N layer exhibits the rate of desired residual carbon, less than 20 atomic%.
• the dispersions of nanoparticles of metal oxide (s) having a reduced content of carbon precursor compounds are in particular dispersions having a low content of compatibilizing agents.
• Such dispersions more particularly comprise less than 5% by mass, in particular less than 1% by mass, of compatibilizing agent (s), relative to the total mass of the dispersion.
• Such dispersions are in particular dispersions of nanoparticles stabilized via the surface potential (zeta potential) of the particles, more precisely by the use of counterions.
• colloidal dispersions of nanoparticles of metal oxide (s) may, for example, be commercially available.
• the carbon content in the N layer formed can be adjusted, after depositing the dispersion of nanoparticles of metal oxide (s) and prior to depositing the overlying layer in the multilayer stack, for example prior to the deposition of the active perovskite layer in the case of a stack multilayer in NIP structure, by subjecting the N-type layer to a carbon removal treatment.
• s metal oxide
• the carbon removal treatment is carried out under low temperature conditions, in particular at a temperature less than or equal to 150 ° C, in particular less than or equal to 120 ° C, in particular less than or equal to 100 ° C, preferably less than or equal to 80 ° C, and more particularly less than or equal to 50 ° C.
• the carbon removal treatment is carried out at room temperature.
• Such a carbon removal treatment can more particularly be a treatment by UV irradiation, by UV-ozone, with ozone and / or by plasma, in particular an oxidizing one.
• N-type conductive layer having the desired carbon content of less than 20 atomic%, from any dispersion of nanoparticles of metal oxide (s), regardless of the carbon content of said dispersion.
• Those skilled in the art are able to adjust the operating conditions for carrying out the carbon removal treatment, in particular the duration of exposure of the free surface of said N layer to UV, UV-ozone, to l. ozone or a plasma, in particular an oxidizer, to achieve the desired reduced carbon content according to the invention.
• the treatment under UV radiation can more particularly consist in irradiating the free surface of said N layer formed by UV light of two wavelengths, for example 185 and 256 nm.
• Any UV light source making it possible to irradiate the surface of said N layer can be used for such irradiation.
• One example is a mercury vapor lamp.
• the treatment of said layer by UV irradiation can be carried out for a period ranging from 5 to 60 minutes, in particular from 10 to 30 minutes.
• the UV irradiation is carried out at a temperature less than or equal to 150 ° C, in particular less than or equal to 100 ° C, preferably less than or equal to 80 ° C, and more particularly less than or equal to 50 ° C. More particularly, the UV irradiation is carried out at room temperature.
• the UV irradiation treatment can be carried out in a vacuum or in a gas.
• the UV irradiation treatment can in particular be carried out in an ambient atmosphere, the UV radiation then transforming the oxygen in the air into ozone; we speak in this case of UV-ozone treatment.
• the UV irradiation treatment can also be carried out under an inert gas such as nitrogen.
• the carbon removal treatment can be an ozone treatment (in the absence of UV irradiation).
• Such ozone treatment can be carried out, for example, by bringing the free surface of the N layer into contact with an atmosphere containing ozone generated by UV irradiation, the sample being placed behind a filter protecting it from said radiation.
• the elimination of carbon can be carried out by plasma treatment, in particular with an oxidizing plasma.
• Oxidizing plasma is, for example, a plasma comprising oxygen or a plasma of a mixture of oxygen and argon.
• the treatment is carried out with an oxygen plasma.
• a person skilled in the art is able to use the equipment necessary to generate such a plasma.
• the other layers of the multilayer stack according to the invention can be made by techniques known to those skilled in the art.
• they are carried out wet, by conventional deposition techniques, that is to say by techniques implementing the deposition of an ink in the liquid state.
• the deposition of a solution during the manufacturing process in particular to form a conductive layer of type P and an active layer of perovskite type, can be carried out by means of a technique as described above for the preparation.
• an N-type conductive layer in particular, all the layers formed during the process steps can be carried out using a single technique chosen from those described above.
• the photovoltaic device may also include electrical connection means, in particular contact points, which make it possible to connect the electrodes in order to supply an electrical circuit with current.
• NIP perovskite-type photovoltaic cell
• the support 11 is a 1.1 mm thick glass substrate covered with a layer of ITO conductive oxide forming the lower electrode 12.
• perovskite materials Two types are tested: of the CH3NH3PM3 type (also noted MAPbL) or of the “double cation” perovskite type Cs x FAi- x Pb (I y Bri- y ) 3, FA symbolizing the formamidinium cation.
• the N-type layer 13 is formed as described below.
• the P-type layer 15 is composed of PT AA doped with a lithium salt, 80 nm thick.
• the upper electrode 16 is a layer of gold, 100 nm thick.
• the active surface of the devices is 0.28 cm 2 and their performance was measured at 25 ° C. under standard lighting conditions (1000 W / m 2 , AM 1.5G).
• the photovoltaic performances of the cells are more particularly measured by recording the current-voltage characteristics of the devices on a Keithley ® SMU 2600 device under AM 1.5G illumination at a power of 1000 Wm 2 .
• the cell under test is illuminated through the Glass / ITO face using an Oriel simulator.
• a mono-crystalline silicon cell calibrated at the Fraunhofer ISE (Friborg, Germany) is used as a reference to ensure that the light power delivered by the simulator is indeed equal to 1000 Wm 2 .
• the characteristic parameters of the operation of the devices are determined from the current-voltage curves.
• Example 1 ink containing a controlled carbon content
• N tin oxide (SnCh) layers are tested in a stack as described above.
• the N layers are formed by spin-coating, operated at room temperature, from separate commercial solutions (called “inks”) of SnCL nanoparticles:
• the particle size of SnCh is in the range of 10-15 nm.
• Dispersions 1 and 2 contain a reduced content of compatibilizers, a source of carbon, compared to dispersion 3.
• Dispersions 1 and 2 lead, after application by spin-coating, to layers of SnCh nanoparticles containing approximately 15 atomic% of carbon, while dispersion 3 results in a layer of SnCL containing approximately 40 atomic% of carbon.
• the carbon content is determined by X-ray induced photoelectron spectrometry (XPS for “X-Ray photoelectron spectrometry”).
• the N layers are formed at room temperature, by spin-coating from separate commercial solutions of AZO or SnCh nanoparticles, if necessary followed by an elimination treatment.
• carbon by UV irradiation, by UV-ozone or by ozone, as detailed below.
• Dispersion 4 is a dispersion of particles of ZnO doped Al or AZO, of average size 12 nm, in 2-propanol.
• the UV irradiation treatment of the N layer, after depositing the dispersion by spin coating, is carried out for 30 minutes, at a wavelength of 185 nm and 256 nm, under an inert atmosphere and room temperature.
• the UV-ozone treatment is carried out by exposure to UV radiation generating ozone of the surface of the N layer, after deposition of the dispersion by spin-coating, under ambient atmosphere and temperature, for 30 minutes in equipment for the JetLight brand.
• the ozone treatment is carried out in the same JetLight equipment and under the same conditions, except that the sample is placed behind a filter avoiding exposure to UV radiation but suitable for exposure to ozone generated during 30 minutes.
• FIG. 2 represents the evolution of the carbon content in an N layer based on AZO nanoparticles as a function of the duration of the UV-ozone treatment.

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• 2019
  • 2019-11-05 FR FR1912397A patent/FR3102887B1/fr active Active
• 2020
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