Transferable electrodes for printed electronics

Abstract

A transferable electrode device comprising a flexible release substrate having a release surface and a transferable electrode comprising at least one conductive layer disposed over the release surface of the release substrate comprising a solution-processed conductive layer, the at least one conductive layer comprising an interface connecting conductive layer interfacing with a receiving surface, the interface connecting conductive layer comprising a carbonaceous conductive layer or an organic conductive layer, the transferable electrode being releasably attached to the release surface of the release substrate.

Description

[Technical field]

[0001] Priority Cross Reference This application claims priority from Australian Provisional Patent Application No. 2022900582, filed March 10, 2022, the contents of which are understood to be incorporated herein by reference.

[0002] The present invention relates to a transferable electrode device that can be used in printed electronics, more particularly in flexible electronics. The present invention is particularly applicable for forming electrodes that can be applied / transferred to flexible electronics substrates, such as printed optoelectronic devices, to form electrodes thereon, and it will be convenient to disclose the present invention below in the context of an exemplary application. However, it should be appreciated that the present invention is not limited to that application and may be used in a number of printed electronics applications, including electronic sensors or light emitting devices, etc. [Background technology]

[0003] The following discussion of the background art is intended to facilitate an understanding of the present invention. It should be recognized, however, that this discussion is not an admission or endorsement that any of the material referred to was published, publicly known, or part of the common general knowledge as of the priority date of the application.

[0004] Printed electronics, such as thin film photovoltaic devices, are traditionally made by successively printing each layer on top of the previous layer to form the final multilayer product. While this allows each layer to have a specialized configuration and composition, the compositions and especially the solvents used in subsequent layers must be carefully selected to minimize, and more preferably prevent, damage to the underlying layers. Nonetheless, some layers, such as the top electrode layer, may still have components and processing regimes that can be detrimental to the underlying layers.

[0005] Top electrodes of thin film photovoltaic devices are traditionally applied using expensive / low throughput vacuum deposition of metals such as silver or gold to an application layer of an electronic carrier substrate with selected underlying electronic layers configured to receive a transferable electrode. Because the process is carried out in a high vacuum chamber, it can be very expensive and difficult to scale up for mass production.

[0006] Alternatively, the electrodes are solution printed / coated directly onto the electronic carrier substrate and then undergo a heat treatment (annealing) process to dry the electrode layer. The heat treatment process may cause partial damage to other layers of the device due to degradation of some of the underlying layers of the device. This solution printing / coating method may also allow undesirable solvents of the wet film to seep into one or more underlying layers of the electronic carrier substrate, potentially damaging one or more of these layers or the interfaces between the layers. Thus, the choice of conductive pastes is limited and the performance of the electrodes is compromised due to chemical compatibility. Summary of the Invention [Problem to be solved by the invention]

[0007] It would therefore be desirable to provide new or improved methods of forming electrodes for flexible electronic devices, such as thin film photovoltaic devices. [Means for solving the problem]

[0008] The present invention relates to transferable electrodes, devices associated with transferable electrodes, flexible electronic devices such as optoelectronic devices incorporating transferable electrodes, methods of forming transferable electrodes, and methods of forming flexible electronic devices incorporating transferable electrodes.

[0009] The first aspect of the present invention is a flexible release substrate including a release surface; a transferable electrode comprising at least one conductive layer disposed overlying a release surface of a release substrate comprising a solution-processed conductive layer; A transferable electrode device comprising: at least one conductive layer comprises an interface-connecting conductive layer that interfaces with the receiving surface, the interface-connecting conductive layer comprising a carbonaceous conductive layer or an organic conductive layer; a transferable electrode releasably attached to a release surface of a release substrate; A transferable electrode device is provided.

[0010] Thus, a first aspect of the present invention relates to a device comprising a transferable electrode, preferably a thin film electrode, disposed on a release substrate having a release surface, e.g., a non-stick surface, or other releasably attached configured surface (discussed below). The release surface provides a surface to which the transferable electrode is releasably attached, affixed, or otherwise adhered. The release substrate can be separated from the transferable electrode once the transferable electrode interfaces with, and is fixed, attached, or otherwise adhered to, a receiving surface.

[0011] The electrode includes at least one conductive layer that is transferable to a location of use, for example, to an electronic carrier substrate having a selected underlying electronic layer configured to receive the transferable electrode at a receiving surface thereon. The conductive layer layup includes at least one interface-connecting conductive layer that is configured to interface with a receiving surface, for example, a receiving surface of an electronic carrier substrate as described later herein. One example illustrated herein is the formation of a flexible optoelectronic device using a transferable electrode as an outer electrode layer of an optoelectronic device layup.

[0012] It should be appreciated that the interface connecting conductive layer is preferably comprised of a composition and configuration that allows the peelable substrate to interface with a suitable receiving surface. By interface connecting, it is meant abutting, engaging, and / or substantially adhering to a receiving surface, such as a receiving surface of an electronic carrier substrate. Thus, the interface connecting layer is typically the outermost layer of the conductive layer layup and the layer furthest away from the release substrate.

[0013] The use of an electrode layer that is formed separately from other layers of the electronic device allows the transferable electrode to be fabricated and heat treated separately from the layup of the intended electronic carrier substrate, thereby isolating the electronic carrier substrate from heat treatment (annealing) and solvent leaching issues associated with the composition and formation of the transferable electrode layer that may otherwise cause some degradation of some of the underlying layers of the optoelectronic device if formed in situ on the electronic carrier substrate. The transferable electrode can include a flexible electrode, for example, a flexible cathode or a flexible anode, depending on the layup of the electronic carrier substrate.

[0014] It should be understood that a solution-processed conductive layer can include any conductive layer formed from a fabrication method in which the materials forming the layer are deposited while such materials are in solution (otherwise known as "wet" processing methods). This is in contrast to "dry" processing methods in which such materials are deposited while in a gas or vapor phase. A solution-processed layer typically includes a material, in this case a conductive material, and a binder, typically an organic binder, which is deposited on the layer. The wetting solution used to form the solution-processed conductive layer typically includes a conductive material, a binder, mixed together in a solvent. Any suitable binder can be used. Examples of suitable binders include organic binders such as one or more of ethyl cellulose, butyl cellulose, nitrocellulose, hydroxyl cellulose, cellulose acetate butyrate, alkyd resins, epoxy resins, phenolic resins, acrylic resins, butyl carbitol, butadiene-styrene rubber, polyvinylpyrrolidone, polyacrylamide, cellulose derivatives, triethyl hexyl phosphate, and sodium lauryl sulfate.

[0015] As used herein, the term "conductive layer" should be understood to mean a thin film having sufficient electrical conductivity to transport a charge or charges, e.g., photogenerated charges, through the layer. The conductive layer may be an electrical conductor or a semiconductor. The "conductive layer" may have multiple functions, including charge selectivity.

[0016] The conductive layer can have any composition suitable for use in solution-printed flexible electronic devices, such as flexible optoelectronic devices. In an embodiment, the at least one conductive layer comprises at least one additional conductive layer selected from a metal-based conductive layer; a carbonaceous conductive layer; an organic conductive layer; or a combination thereof. In an embodiment, the at least one additional conductive layer comprises a metal-based conductive layer.

[0017] The transferable electrode can be formed from a single conductive layer composition, or from two or more conductive layer compositions. In embodiments, the transferable electrode comprises at least one metal-based conductive layer disposed overlying the release surface of a release substrate. In some embodiments, the transferable electrode comprises at least one carbonaceous conductive layer disposed overlying the release surface of a release substrate. In some embodiments, the transferable electrode comprises at least one organic conductive layer disposed overlying the release surface of a release substrate. In other embodiments, the transferable electrode comprises at least one metal-based conductive layer disposed overlying a release surface of a release substrate; an interface connection conductive layer disposed on the metallic conductive layer; The conductive layer includes at least two conductive layers.

[0018] In embodiments, the transferable electrode comprises a single layer electrode having only one conductive layer (carbonaceous or organic conductive layer), hi other embodiments, the transferable electrode comprises a bilayer electrode, preferably including both a metallic conductive layer and an interface connecting conductive layer.

[0019] In this electrode composition layup, the transferable electrode can include one or more metal-based conductive layers. Similarly, the transferable electrode can include one or more interface-connecting conductive layers, including a carbonaceous conductive layer or an organic conductive layer. In an embodiment, the layup of the transferable electrode can have a first layer or layered portion of a metal-based conductive material, followed by a second layer or layered portion of an interface-connecting conductive layer. However, it should be recognized that, if desired, the layers can be applied sequentially to form a layered structure of a metal-based conductive layer, followed by an interface-connecting conductive layer (carbonaceous conductive layer or organic conductive layer). The interface-connecting conductive layer is the final outer layer of the transferable electrode, and provides the surface in the layup that is located furthest from the release substrate and is positioned to interface with the receiving surface.

[0020] Barrier encapsulation is useful for protecting flexible electronic devices from degradation due to interaction of the functional layers of the device with the ambient atmosphere (i.e., moisture and oxygen in the ambient atmosphere). In some embodiments, the transferable electrode further comprises at least one barrier film layer disposed between the release substrate and the at least one conductive layer. The barrier film layer is thus disposed between the conductive layer and the release substrate such that when the release substrate is removed (see embodiments of the invention described below), the barrier film forms a protective layer over the conductive layer and the transferable electrode. The barrier film can comprise any suitable material. In embodiments, the barrier film can comprise a single thin film barrier layer, or a multi-layer thin film barrier structure. This can be any suitable material that provides barrier properties, including, for example, polymeric barrier materials such as ethylene-vinyl acetate (EVA), polydimethylsiloxane (PDMS) or poly(1,3,5-trimethyl-1,3,5-trivinylcyclotrisiloxane) (pV3D3), or organic-inorganic nanocomposites such as silica-based materials, including as perhydropolysilazanes (PHPS), or metal oxide barrier layers such as aluminum oxide, silicon oxide, silicon nitride, titanium dioxide, or tin oxide. Multilayer barrier structures can include stacks of alternating organic or inorganic layers, or successive layers of organic or inorganic barrier materials such as those mentioned. It should be recognized that the barrier film is preferably a very thin film, too thin to handle. The barrier film has mechanical and physical properties that make it very thin and therefore not possible to make it into a standalone film.

[0021] The conductive layer can have any suitable conductive composition.

[0022] Suitable metal-based conductive layers, layers include conductive compositions based on Au, Ag, Al, Mg, Cu, or suitable alloys thereof, etc. In an embodiment, at least one metal-based conductive layer comprises an Ag-, Al-, Cu-, or Au-based layer, preferably an Ag-, Al-, or Cu-based layer.

[0023] At least one organic conductive layer preferably comprises a charge transport layer, preferably a PEDOT-based conductive layer. Suitable PEDOT-based conductive layers include PEDOT or PEDOT-containing compositions, such as poly(3,4-ethylenedioxythiophene):poly(styrenesulfonic acid) (PEDOT:PSS).

[0024] It should be understood that a carbonaceous conductive layer includes a layer that contains or includes a composition that is composed of and / or rich in carbon or carbonaceous materials. Suitable carbonaceous conductive layers include compositions that include carbon, graphite / carbon black, carbon nanotubes (CNTs), vapor-grown carbon fibers, or graphene, etc. At least one carbonaceous conductive layer is preferably formed using a carbonaceous / carbonaceous paste that typically includes a conductive carbonaceous filler, a binder material, and an organic solvent. In an embodiment, the conductive carbonaceous filler is selected from graphite, carbon black, carbon nanotubes, vapor-grown carbon fibers, graphene, or a combination thereof. In an embodiment, the binder material is selected from ethyl cellulose, butyl cellulose, nitrocellulose, hydroxyl cellulose, cellulose acetate butyrate, alkyd resin, epoxy resin, butadiene-styrene rubber, phenolic resin, acrylic resin, butyl carbitol, butadiene-styrene rubber, polyvinylpyrrolidone, polyacrylamide, cellulose derivatives, triethyl hexyl phosphate, and sodium lauryl sulfate, cellulosic polymers, or combinations thereof. In an embodiment, the organic solvent is selected from terpineol, dibutyl phthalate, butyl carbitol, dibutyl carbitol, turpentine, butyl glycol ether, butyl carbitol acetate, ethylene glycol ether acetate, tributyl citrate, and tributyl phosphate, propylene glycol methyl ether acetate toluene, diethylene glycol butyl ether, propanol, benzyl alcohol, isopropyl alcohol, ethanol, methanol, dimethylformamide, dimethyl sulfoxide, chloroform, diethylene glycol derivatives, toluene, xylene isopropanol, ethyl acetate, water, chlorobenzene, or combinations thereof. Examples of commercially available carbon-based / carbonaceous pastes having this type of composition include Dycotec DM-CAP-4701-S and Dycotec DM-CAP-4311-S from Dycotec Materials Ltd., UK; and Jelcon CH-8 from Jujo Chemical Co., Japan.In an embodiment, the carbonaceous conductive layer comprises a porous, preferably macroporous, carbonaceous conductive membrane.

[0025] In some embodiments, the transferable electrode includes a metallic conductive layer overlying the release surface of the release substrate, and a carbonaceous conductive layer overlying the metallic conductive layer.

[0026] In some embodiments, the transferable electrode comprises a metal-based conductive layer overlying the release surface of the release substrate and an organic conductive layer, preferably a PEDOT-based carbonaceous conductive layer overlying the metal-based conductive layer. The organic conductive layer is preferably a charge transport layer.

[0027] The transferable electrode of the present invention is preferably a thin film electrode. Thin film electrodes are typically too thin to be self-supporting (i.e., physically unstable) and therefore require a release substrate to be transported and manipulated. In an embodiment, at least one conductive layer has a dry layer thickness of 1 μm to 100 μm, preferably 10 to 80 μm, more preferably 20 to 60 μm, and even more preferably about 40 μm. In an embodiment, the interface connection conductive layer (and in particular the carbonaceous conductive-based interface connection conductive layer) has a dry layer thickness of between 10 and 50 μm, preferably 15 to 40 μm, and more preferably 30 to 40 μm.

[0028] The release substrate can include any suitable material. In an embodiment, the release substrate includes a flexible polymer or flexible film. Examples include polymeric films such as polyethylene terephthalate (PET) film, polyethylene naphthalate (PEN), polypropylene (PP), ethylene tetrafluoroethylene (ETFE), or may include paper-based or metal-based substrates such as paper or aluminum foil.

[0029] The transferable electrode is releasably attached to the release surface of the release substrate. In this sense, the release surface provides a surface onto which the transferable electrode is releasably stuck, attached, or otherwise attached. Releasably attached should be understood to mean that the transferable electrode is stuck, attached, or otherwise attached to the release substrate in such a way that it also allows the transferable electrode to be subsequently separated from the transferable electrode using a selected action, such as delamination / force, heat, radiation, or chemical reaction. Once the transferable electrode interfaces with and is fixed (or otherwise adhered) to the receiving surface, the release substrate is typically separated from the transferable electrode. The release surface on the release substrate can take several forms that allow the release substrate to be detached or otherwise removed from the transferable electrode.

[0030] In some embodiments, the release surface comprises an anti-stick surface, preferably an anti-stick coating, or a low adhesion coating. The release substrate is preferably coated with an anti-stick coating. It should be appreciated that the anti-stick surface and / or coating is a surface engineered to reduce the ability of other materials to stick to it. In this sense, the coating has a composition that provides a low adhesion surface. The anti-stick surface may be provided by a low surface energy polymer. The anti-stick coating may comprise a low surface energy polymer, for example, selected from the group consisting of fluorinated polymers and silicone polymers. The release surface is preferably selected from the group consisting of fluorinated polymers and silicone polymers. Examples include polytetrafluoroethylene (PTFE) or silicone derivatives such as siloxane. In this embodiment, the release substrate is separable from the transferable electrode by delaminating / removing the transferable electrode from the anti-stick surface.

[0031] In another embodiment, the release surface comprises an activatable adhesive that can be activated to separate the transferable electrode from the release substrate. Examples of suitable activatable adhesives include heat-activatable adhesive polymers, preferably comprising a thermoplastic polymer selected from the group consisting of ethylene-vinyl acetate (EVA) copolymer, polyethylene, polyethylene oxide (PEO), and polystyrene (PS). In this embodiment, the release substrate is separable from the transferable electrode when the activatable adhesive is activated, for example, using heat for a heat-activatable adhesive. Here, the activatable adhesive is heat-activatable at a temperature sufficient to peel / separate the release substrate from the transferable electrode.

[0032] As used herein, it should be appreciated that an "activatable" layer, adhesive, or adhesive polymer is adapted to be functionally activated, as needed, to bond or debond by an external stimulus, such as heat, radiation (such as actinic light), or chemical treatment.

[0033] In another embodiment, the release surface includes a low cohesion sacrificial layer sandwiched between a flexible release substrate and a transferable electrode, the low cohesion sacrificial layer having an inherently low cohesion or having a low cohesion when activated such that the flexible release substrate can be separated from the transferable electrode by breaking the low cohesion sacrificial layer. The low cohesion sacrificial layer can include at least one of a low cohesion organic non-polymeric solid; or an activatable adhesive that is activated by heat or radiation to break the low cohesion sacrificial layer and thereby separate the transferable electrode from the release substrate. In this embodiment, the activatable adhesive can be, for example, a thermoplastic polymer selected from the group consisting of ethylene-vinyl acetate (EVA) copolymer, polyethylene, polyethylene oxide (PEO), and polystyrene (PS), or a photodepolymerizable polymeric composition, preferably selected from the group consisting of poly(phthalaldehyde) (PPHA) combined with a photoacid generator (PAG), poly(acetal) combined with a PAG, and polylactide (PLA) combined with TiO2. In some embodiments, the low cohesion sacrificial layer can be conductive, so that any residue does not interfere with the conductive function of the transferable electrode. The low cohesion sacrificial layer can have any suitable thickness. In some embodiments, the low cohesion sacrificial layer has a thickness of less than 100 nm, preferably less than 20 nm. In this embodiment, the release substrate can be separated from the transferable electrode by (i) activating the activatable adhesive by heat or radiation, and (ii) breaking the low cohesion sacrificial layer.

[0034] A second aspect of the present invention provides an optoelectronic device incorporating a transferable electrode apparatus according to the first aspect of the present invention. a flexible substrate coated with a transparent conductive oxide coating; a first charge transport layer disposed over the flexible substrate; at least one photoactive layer overlying the first charge transport layer; a transferable electrode device according to a first aspect of the invention, disposed over a photoactive layer, and an interface connecting conductive layer disposed over, and preferably interfaced with (attached / bonded and engaged with) the photoactive layer; The present invention provides an optoelectronic device comprising:

[0035] In this second aspect, the optoelectronic device is a multi-layer optoelectronic device formed on a flexible substrate and overlaid with a transferable electrode arrangement of the first aspect of the invention, the interface connecting conductive layer of the transferable electrode interfacing with at least one photoactive layer in the optoelectronic device.

[0036] In some embodiments, the transferable electrode arrangement is placed in direct engagement with a photoactive layer of an optoelectronic device. In these embodiments, the transferable electrode preferably comprises a metal-based conductive layer overlying the release surface of the release substrate, and the interface connecting conductive layer comprises an organic conductive layer, preferably a charge transport layer, more preferably a PEDOT-based conductive layer overlying the metal-based conductive layer.

[0037] In other embodiments, the transferable electrode device is engaged with a further layer disposed over the photoactive layer. In this regard, the multi-layer composition of the optoelectronic device may include the layers defined above, along with one or more additional layers. For example, in some embodiments, the optoelectronic device further includes a second charge transport layer disposed over the flexible substrate, disposed between at least one photoactive layer and the transferable electrode. It should be recognized that other suitable layers may also be included in the layup, depending on the desired optoelectronic device configuration. When the transferable electrode device is engaged with (disposed over) a second charge transport layer, the transferable electrode preferably includes a metal-based conductive layer disposed over the release surface of the release substrate, and the interface connecting conductive layer includes a carbonaceous conductive layer disposed over the metal-based conductive layer. In this embodiment, the interface connecting conductive layer of the transferable electrode interfaces with (is in direct engagement with and attached / adhered to) the second charge transport layer in the optoelectronic device. In an embodiment, the carbonaceous conductive layer includes a porous, preferably macroporous, carbonaceous conductive film.

[0038] The first and second charge transport layers can have any suitable composition. In embodiments, at least one of the first or second charge transport layers comprises at least one hole transport layer, at least one electron transport layer, or at least one photovoltaic cell active layer. These layers can have a variety of compositions depending on the desired optoelectronic device configuration. Suitable hole transport layers include 2,2',7,7'-tetrakis-(N,N-di-4-methoxyphenylamino)-9,9'-spirobifluorene (Spiro-OMeTAD), poly[(2,5-bis(2-hexyldecyloxy)phenylene)-alt-(5,6-difluoro-4,7-di(thiophen-2-yl)benzo[c][1,2,5]-thiadiazole)] (PPDT2FBT), poly(3,4-ethylenedioxythiophene) (PEDOT), poly(3,4-ethylenedioxythiophene and polystyrenesulfonate blends (PEDOT:PSS), poly(4,4-dioctylcyclopentadithiophene); P3HT, doped P3HT (poly(3-hexylthiophene) transparent conductive polymers such as at least one of poly[N-9″-heptadecanyl-2,7-carbazole-alt-5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole)] (PCDTBT), poly[2,6-(4,4-bis-(2-ethylhexyl)-4H-cyclopenta[2,1-b;3,4-b′]dithiophene)-alt-4,7(2,1,3-benzothiadiazole)] (PCPDTBT), poly(N-alkyldiketopyrrolopyrroledithienylthieno[3,2-b]thiophene) (DPP-DTT), indene-C60 bisadduct (ICBA), or MoO3; Suitable electron transport layers include transparent conductive oxides such as at least one of tin oxide, nickel oxide, zinc oxide, titanium dioxide, or tungsten trioxide, or transparent conductive polymers such as, for example, [6,6]-phenyl-C61-butyric acid methyl ester (PC60BM), [6,6]-phenyl-C70-butyric acid methyl ester (PC70BM), or ethoxylated polyethyleneimine (PEIE), or transparent conductive polymers such as, for example, C 60 Or C 70 and mixtures of pure fullerenes such as Suitable photovoltaic cell active layers include organic photovoltaic active layers, such as any fullerene and non-fullerene polymeric electron acceptor material, such as phenyl-C61-butyric acid methyl ester (PCBM), and any polymeric electron donor material, such as poly(3-hexylthiophene) (P3HT); or perovskite photoactive layers.

[0039] In some embodiments, the transferable electrode device includes a metal-based conductive layer disposed overlying the release surface of a release substrate and an organic conductive layer disposed in direct engagement with (interfaced with and attached / adhered to) a photoactive layer of an optoelectronic device, the photoactive layer preferably being comprised of a mixture of a polymeric electron donor (i.e., P3HT) and a polymeric electron acceptor (i.e., PCBM) or a perovskite photoactive layer.

[0040] In some embodiments, at least one hole transport layer comprises an organic or inorganic conductor or semiconductor.In some embodiments, at least one electron transport layer comprises an organic or inorganic conductor or semiconductor.

[0041] In an exemplary embodiment, at least one of the first charge transport layer or the second charge transport layer is selected from at least one of Spiro-OMeTAD, PPDT2FBT, or phenyl-C61-butyric acid methyl ester (PCBM) / ethoxylated polyethyleneimine (PEIE).

[0042] It should be noted that the composition of the first charge transport layer or the second charge transport layer may include one or more additives.

[0043] The photoactive layer may include a suitable photoactive composition. One exemplary photoactive layer includes at least one perovskite layer. It should be appreciated that the photoactive perovskite layer includes a light-absorbing perovskite semiconductor that is essentially composed of perovskite crystallites. As discussed later in this specification, the term "perovskite" as used herein refers to (a) a material having a three-dimensional crystal structure related to that of CaTiO3, or (b) a material including a layer of material, the layer having a structure related to that of CaTiO3. Perovskite materials can be represented by the formula [A][M][X]3, where [A] is at least one cation, [M] is at least one cation, and [X] is at least one anion.

[0044] In an embodiment, the transparent conductive oxide (TCO) coating is selected from at least one of tin-doped indium oxide (ITO), fluoride-doped tin oxide (FTO), doped zinc oxide such as aluminum-doped zinc oxide (AZO), or indium-doped cadmium oxide.

[0045] The flexible substrate preferably comprises a polymer, preferably a polymer film, more preferably a polyethylene terephthalate (PET), polyethylene naphthalate (PEN), or ethylene tetrafluoroethylene (ETFE) film, more preferably a polyethylene terephthalate film.

[0046] For practical purposes, the release substrate of the transferable electrode device is sacrificial and is therefore preferably removed. Thus, the optoelectronic device of the second embodiment may have a release substrate that is at least partially separated from covering the transferable electrode. In an embodiment, the release substrate is at least partially separated from covering at least one metal-based conductive layer. If the transferable electrode includes a barrier layer, the release substrate is partially separated from covering the barrier film layer. More preferably, the optoelectronic device according to the second aspect has a release substrate that is substantially separated from covering the transferable electrode. In an embodiment, the release substrate is substantially separated from covering at least one metal-based conductive layer. If the transferable electrode includes a barrier layer, the release substrate is substantially separated from covering the barrier film layer.

[0047] A third aspect of the present invention is providing a flexible release substrate including a release surface; applying at least one layer of a conductive medium to a release surface of a release substrate, the conductive medium comprising a flowable mixture of a conductive composition and a solvent, the at least one layer of the conductive medium comprising an interface connecting conductive composition configured to form an interface connecting conductive layer to an interface with a receiving surface, the interface connecting conductive composition comprising a flowable mixture of one of a carbonaceous conductive composition or an organic conductive composition and a solvent; heat treating at least one layer of conductive medium to remove said solvent from each layer of conductive medium; thereby forming a transferable electrode on the release substrate; 1. A method of forming a transferable electrode for a flexible electronic device, comprising: The method provides a method in which the transferable electrode is releasably attached to a release surface of a release substrate.

[0048] The method of this third aspect of the invention provides a novel method of electrode fabrication where the electrodes are separately formed on a release substrate which is then transferred and applied to an electronic carrier substrate having a selected underlying electronic layer configured on its overlying receiving surface to receive the transferable electrode. This allows the electrodes to be fabricated separately from the electronic carrier substrate, thus avoiding the deleterious effects of heat treatment (annealing) and solvent leaching issues that can degrade layers of the electronic carrier substrate if the electrodes are formed / printed in situ.

[0049] Each layer of conductive medium is applied using a solution processing method. Solution processing methods should be understood to include layer preparation methods in which the materials forming the layer are deposited while in solution (otherwise known as "wet" processing methods). This is in contrast to "dry" processing methods in which such materials are deposited while in a gas or vapor phase. Conductive compositions applied using solution processing methods typically include a conductive composition, typically a conductive material and a binder, mixed together in a solvent. Any suitable binder can be used. Examples of suitable binders are discussed above in connection with the first aspect of the invention.

[0050] The conductive medium, conductive material (and conductive composition) can have any composition suitable for use in solution printed flexible electronic devices, such as flexible optoelectronic devices. In an embodiment, at least one layer of the conductive medium further comprises at least one further layer comprising a flowable mixture of at least one of a metal-based composition, a carbonaceous conductive composition, or an organic conductive composition and a solvent. It should be appreciated that the metal-based composition, the carbonaceous conductive composition, and the organic conductive composition typically comprise a metal-based material and binder, a carbonaceous conductive material and binder, and an organic conductive material and binder, respectively. Again, any suitable binder can be used. Examples of suitable binders are discussed above in connection with the first aspect of the invention.

[0051] The transferable electrode can be formed from a single conductive layer composition, or from two or more conductive layer compositions. In embodiments, the transferable electrode includes at least two layers of conductive medium, and the applying step includes: applying at least one layer of a metal-based conductive medium comprising a flowable mixture of a metal-based composition and a solvent to a release substrate to form a first conductive layer; applying at least one layer of the interface connecting conductive composition to the first conductive layer to form an interface connecting conductive layer.

[0052] A heat treating step (also known as an annealing step) is used to remove solvent from the applied conductive media and dry the layers. The heat treating step is preferably performed after the layers are applied, and includes heat treating the transferable electrode after each conductive media layer is applied to itself. However, it should be recognized that in other embodiments, two or more layers may be applied before the combined layers are heat treated.

[0053] The transferable electrode preferably comprises at least two layers of conductive medium, including at least one layer of metal-based conductive composition; and at least one layer of interface-connecting conductive composition, the outer layer comprising the interface-connecting conductive composition. When two or more layers of different conductive materials are applied, it is preferred that at least one layer of the metal-based conductive medium is heat-treated prior to application of the interface-connecting conductive composition thereto. In this sense, the interface-connecting conductive composition is heat-treated after application to the first conductive layer.

[0054] The flowable mixture of the metal-based conductive media comprises a mixture of the metal-based composition and a solvent. Suitable solvents include terpineol, dibutyl phthalate, butyl carbitol, dibutyl carbitol, turpentine, butyl glycol ether, butyl carbitol acetate, ethylene glycol ether acetate, tributyl citrate, and tributyl phosphate, propylene glycol methyl ether acetate toluene, diethylene glycol butyl ether, propanol, benzyl alcohol, isopropyl alcohol, ethanol, methanol, dimethylformamide, dimethylsulfoxide, chloroform, diethylene glycol derivatives, toluene, xylene isopropanol, ethyl acetate, water, chlorobenzene, or combinations thereof.

[0055] The flowable mixture of carbonaceous conductive material includes a mixture of a metal-based composition and a solvent, suitable solvents include terpineol, dibutyl phthalate, butyl carbitol, dibutyl carbitol, turpentine, butyl glycol ether, butyl carbitol acetate, ethylene glycol ether acetate, tributyl citrate, and tributyl phosphate, propylene glycol methyl ether acetate toluene, diethylene glycol butyl ether, propanol, benzyl alcohol, isopropyl alcohol, ethanol, methanol, dimethylformamide, dimethylsulfoxide, chloroform, diethylene glycol derivatives, toluene, xylene isopropanol, ethyl acetate, water, chlorobenzene, or combinations thereof.

[0056] The flowable mixture of organic conductive material includes a mixture of an organic conductive composition and a solvent. Suitable solvents include terpineol, dibutyl phthalate, butyl carbitol, dibutyl carbitol, turpentine, butyl glycol ether, butyl carbitol acetate, ethylene glycol ether acetate, tributyl citrate, and tributyl phosphate, propylene glycol methyl ether acetate toluene, diethylene glycol butyl ether, propanol, benzyl alcohol, isopropyl alcohol, ethanol, methanol, dimethylformamide, dimethylsulfoxide, chloroform, diethylene glycol derivatives, toluene, xylene isopropanol, ethyl acetate, water, chlorobenzene, or combinations thereof.

[0057] A variety of heat treatment regimes can be used. In some embodiments, the heat treatment comprises heating at least one layer of the conductive medium at at least 80° C. for at least 5 minutes, preferably at least 100° C., more preferably at least 120° C., more preferably at 135° C. In embodiments, the heat treatment regime is carried out for 0-10 minutes, preferably 5 minutes. In some embodiments, the heat treatment comprises heating at least one layer of the conductive medium at 135° C. for 0-10 minutes, preferably 5 minutes.

[0058] Barrier encapsulants are useful for protecting photovoltaic devices from degradation due to interaction of the functional layers of the device with the ambient atmosphere (i.e., moisture and oxygen). Using the methods of the present invention, a barrier encapsulant layer can be effectively applied to the device either neat or as a multi-layer system containing a barrier layer encapsulant and a conductive layer or layers of an electrode. Thus, in some embodiments, the transferable electrode further comprises at least one barrier film layer disposed between the release substrate and the at least one conductive layer. In such embodiments, the method includes: The method further includes applying at least one barrier film material composition between the release substrate and the at least one layer of conductive medium to form at least one barrier film layer, wherein the at least one layer of conductive medium is printed onto the at least one barrier film layer.

[0059] The barrier film material composition can have any suitable composition. In an embodiment, the barrier film material composition can include a single thin film barrier layer or a multi-layer thin film barrier structure. This can be any suitable material that provides barrier properties, including, for example, polymeric barrier materials such as ethylene-vinyl acetate (EVA), polydimethylsiloxane (PDMS), or poly(1,3,5-trimethyl-1,3,5-trivinylcyclotrisiloxane) (pV3D3), or organic-inorganic nanocomposites such as silica-based materials including perhydropolysilazane (PHPS), or metal oxide barrier layers such as aluminum oxide, silicon oxide, silicon nitride, or titanium dioxide. A multi-layer barrier structure can include a stack of alternating organic or inorganic layers, or successive layers of organic or inorganic barrier materials such as those mentioned. It should be recognized that the barrier film is preferably a very thin film, too thin to handle. The barrier film has mechanical and physical properties that make it too thin to be a standalone film.

[0060] The conductive layer can have any suitable conductive composition.

[0061] Suitable metal-based conductive layers include conductive compositions based on Au, Ag, Al, Mg, Cu, or suitable alloys thereof, etc. In embodiments, at least one metal-based conductive layer includes an Ag, Cu, Al, or Au-based layer. These layers can be formed using a metal-based conductive medium, such as a metal-based paste, preferably an Ag, Cu, or Al-containing paste.

[0062] At least one organic conductive layer preferably comprises a charge transport layer, preferably a PEDOT-based conductive layer. Suitable PEDOT-based conductive layers include PEDOT or PEDOT-containing compositions, such as poly(3,4-ethylenedioxythiophene):poly(styrenesulfonic acid) (PEDOT:PSS).

[0063] The carbonaceous conductive layer can be formed using any suitable conductive carbonaceous composition. Suitable carbonaceous conductive layers include conductive carbonaceous compositions including carbon, graphite / carbon black, carbon nanotubes (CNTs), vapor grown carbon fibers, or graphene, etc. In an embodiment, the carbonaceous conductive layer comprises a porous, preferably macroporous, carbonaceous conductive film.

[0064] At least one carbonaceous conductive layer is preferably formed using a carbonaceous / carbonaceous paste that typically includes a conductive carbonaceous filler, a binder material, and an organic solvent. In an embodiment, the conductive carbonaceous filler is selected from graphite, carbon black, carbon nanotubes, vapor-grown carbon fibers, graphene, or a combination thereof. In an embodiment, the binder material is selected from ethyl cellulose, butyl cellulose, nitrocellulose, hydroxyl cellulose, cellulose acetate butyrate, alkyd resin, epoxy resin, butadiene-styrene rubber, phenolic resin, acrylic resin, butyl carbitol, butadiene-styrene rubber, polyvinylpyrrolidone, polyacrylamide, cellulose derivatives, triethyl hexyl phosphate, and sodium lauryl sulfate, cellulose-based polymers, or a combination thereof. In embodiments, the organic solvent is selected from terpineol, dibutyl phthalate, butyl carbitol, dibutyl carbitol, turpentine, butyl glycol ether, butyl carbitol acetate, ethylene glycol ether acetate, tributyl citrate, and tributyl phosphate, propylene glycol methyl ether acetate toluene, diethylene glycol butyl ether, propanol, benzyl alcohol, isopropyl alcohol, ethanol, methanol, dimethylformamide, dimethylsulfoxide, chloroform, diethylene glycol derivatives, toluene, xylene isopropanol, ethyl acetate, water, chlorobenzene, or combinations thereof.

[0065] As mentioned in the first aspect, the transferable electrode of the present invention is preferably a thin film electrode. In an embodiment, at least one conductive layer has a dry layer of 1 μm to 100 μm, preferably 10 to 80 μm, more preferably 20 to 60 μm, and even more preferably about 30 μm.

[0066] The release substrate can include any suitable material. In embodiments, the release substrate includes a flexible polymer. In some embodiments, the release substrate can include a flexible film, preferably a polymer film such as polyethylene terephthalate (PET) film, polyethylene naphthalate (PEN), polypropylene (PP), ethylene tetrafluoroethylene (ETFE), or a paper-based or metal-based substrate, such as paper or aluminum foil.

[0067] As discussed above, the release surface provides a surface to which the transferable electrodes are releasably affixed, affixed, or otherwise attached. The release substrate can be separated from the transferable electrodes once the transferable electrodes are interfaced with and secured (or otherwise adhered) to the receiving surface. The release surface on the release substrate can take several forms that allow the release substrate to be detached or otherwise removed from the transferable electrodes.

[0068] In some embodiments, the release surface comprises an anti-stick surface, preferably an anti-stick coating, or a low adhesion coating. Again, it should be appreciated that the anti-stick surface and / or coating is a surface engineered to reduce the ability of other materials to stick to it. In this sense, the coating has a composition that results in a low adhesion surface. As will be appreciated by those skilled in the art, the anti-stick surface is inherently less susceptible to adhesion due to the low surface energy composition on the surface, and therefore does not require heat activation to acquire anti-stick properties. The anti-stick surface may be provided by a polymer selected from the group consisting of low surface energy polymers, for example fluorinated polymers such as polytetrafluoroethylene (PTFE), and silicone polymers such as polydimethylsiloxane (PDMS). The anti-stick surface may be the surface of an anti-stick coating on a flexible release substrate. Suitable anti-stick coatings are generally coatings of low surface energy polymers as described above. Alternatively, the flexible release substrate may comprise a free-standing film of a suitable low surface energy polymer, and the anti-stick surface is the surface of that film.

[0069] The release surface is preferably selected from the group consisting of fluorinated polymers and silicone polymers. Examples include polytetrafluoroethylene (PTFE) or silicone derivatives such as siloxane. In this embodiment, the release substrate is separable from the transferable electrode by delaminating / removing the transferable electrode from the anti-stick surface.

[0070] In another embodiment, the release surface comprises an activatable adhesive that can be activated to separate the transferable electrode from the release substrate. Examples of suitable activatable adhesives include heat-activatable adhesive polymers, preferably comprising a thermoplastic polymer selected from the group consisting of ethylene-vinyl acetate (EVA) copolymer, polyethylene, polyethylene oxide (PEO), and polystyrene (PS). In this embodiment, the release substrate is separable from the transferable electrode when the activatable adhesive is activated, for example, using heat for a heat-activatable adhesive. Here, the activatable adhesive is heat-activatable at a temperature sufficient to peel the release substrate from the transferable electrode.

[0071] In another embodiment, the release surface includes a low cohesion sacrificial layer sandwiched between a flexible release substrate and a transferable electrode, the low cohesion sacrificial layer having an inherently low cohesion or having a low cohesion when activated such that the flexible release substrate can be separated from the transferable electrode by breaking the low cohesion sacrificial layer. The low cohesion sacrificial layer can include at least one of a low cohesion organic non-polymeric solid; or an activatable adhesive that is activated by heat or radiation to break the low cohesion sacrificial layer and thereby separate the transferable electrode from the release substrate. In this embodiment, the activatable adhesive can be, for example, a thermoplastic polymer selected from the group consisting of ethylene-vinyl acetate (EVA) copolymer, polyethylene, polyethylene oxide (PEO), and polystyrene (PS), or a photodepolymerizable polymeric composition, preferably selected from the group consisting of poly(phthalaldehyde) (PPHA) combined with a photoacid generator (PAG), poly(acetal) combined with a PAG, and polylactide (PLA) combined with TiO2. In this embodiment, the release substrate is separable from the transferable electrode by (i) activating the activatable adhesive with heat or radiation, and (ii) destroying the low cohesive strength sacrificial layer.

[0072] Each layer of conductive medium can be applied to the release substrate and / or subsequent layers to form the transferable electrodes using any suitable method, such as at least one of casting, doctor blading, blade coating, bar coating, screen printing, inkjet printing, pad printing, knife coating, meniscus coating, slot die coating, gravure printing, reverse gravure printing, kiss coating, microroll coating, curtain coating, slide coating, spray coating, flexographic printing, offset printing, rotary screen printing, or dip coating. In an exemplary embodiment, each layer of conductive medium can be applied to the release substrate and / or subsequent layers using at least one of doctor blading; screen printing, slot die, gravure, or reverse gravure methods.

[0073] The flexible electrodes of the present invention allow for a series of pre-treatments on the electrode prior to the pressing step that are not possible using conventional direct deposition methods. In an embodiment, the method comprises: pre-pressing the electrode to improve the inter-particle connectivity of the electrode and the inter-layer connectivity of the conductive layer; A process of heat treatment at high temperature for a long time, or At least one solvent exchange process The method may further include at least one pretreatment step to the transferable electrode prior to applying the transferable electrode to the surface of the electronic carrier substrate, selected from at least one of:

[0074] Another advantage of the third aspect of the invention includes the relative reduction in thickness of the formed electrodes compared to electrodes printed on an electronic carrier substrate, which can improve the flexibility and density of the device.

[0075] The present invention also allows electrodes to be fabricated in ambient air and transferred onto an electronic carrier substrate, as compared to conventional electrode deposition / fabrication methods involving expensive / low throughput vacuum deposition of the top electrode.

[0076] As mentioned above, the transferable electrode typically comprises a thin-film electrode that is too thin to be free-standing, and is therefore transported and manipulated with the aid of a release substrate. Thus, the fourth aspect of the present invention involves transferring the transferable electrode to an electronic carrier substrate via a release substrate (which typically functions as a sacrificial layer). In this sense, the transferable thin-film electrode is not configurable as a free-standing electrode that can be pressed directly onto the electronic carrier substrate without a support substrate.

[0077] A fourth aspect of the present invention is a method of forming a flexible electronic device comprising the steps of: A. Providing a transferable electrode device according to the first aspect of the invention, or a transferable electrode such as formed according to the method of the third aspect of the invention; B. providing an electronic carrier substrate having a selected underlying electronic layer configured to receive a transferable electrode on an overlying receiving surface thereof; C. applying a transferable electrode to a receiving surface of an electronic carrier substrate; D. Removing the release substrate from the transferable electrode; Including, Thereby, a method is provided for producing electronic devices having transferable electrodes applied thereto.

[0078] A further aspect of the present invention is a method of forming a flexible electronic device comprising the steps of: A. forming a transferable electrode according to a third aspect of the present invention; B. providing an electronic carrier substrate having a selected underlying electronic layer configured to receive a transferable electrode on an overlying receiving surface thereof; C. applying a transferable electrode to a receiving surface of an electronic carrier substrate; D. Removing the release substrate from the transferable electrode; Including, Thereby, a method is provided for producing electronic devices having transferable electrodes applied thereto.

[0079] In this fourth aspect, an electronic device, such as an optoelectronic device, is provided as an unfinished electronic carrier substrate having a selected underlying electronic layer configured to receive a transferable electrode at its overlying receiving surface. The electronic carrier substrate is typically a multi-layer flexible electronic device. The electronic carrier substrate is overlaid with a transferable electrode arrangement of the first aspect of the invention or as formed using the method of the third aspect of the invention.

[0080] For practical purposes, the release substrate of the transferable electrode device is sacrificial and is therefore preferably removed. The transferable electrode device (electrodes on the release surface of the release substrate) allows the electrode layer, typically a thin film layer, to be safely transferred to an electronic carrier substrate, and then the sacrificial release substrate can then be separated from the electrode stack or otherwise removed to expose the electrodes and complete the fabrication of the electronic device. In this way, fully printed, high performance electronic devices can be produced using this method, which can be scaled up using, for example, a high throughput roll-to-roll process.

[0081] The transferable electrode can be applied to the receiving surface of the electronic carrier substrate by any suitable method. One preferred application method is to press and / or press the transferable electrode onto the receiving surface of the electronic carrier substrate. The electrode film is transferred to the device by pressing, since the outer layer of the transferable electrode tends to bond to the top layer of the device. This bonding is particularly evident when the outermost layer of the transferable electrode is a carbonaceous layer and the top layer of the electronic carrier substrate is a charge transport layer. Any suitable pressing / pressing process can be used. For example, the pressing / pressing process can include a roll press such as a calendar press / laminator; a uniaxial press; or an isostatic press. In an embodiment, the transferable electrode is applied to the electronic carrier substrate by pressing, preferably by a pressing device, more preferably by a calendar press.

[0082] In various embodiments, the electronic device comprises an optoelectronic device. In these embodiments, the electronic carrier substrate preferably comprises: a flexible substrate coated with a transparent conductive oxide coating; a first charge transport layer disposed over the flexible substrate; at least one photoactive layer overlying the first charge transport layer; Including, The receiving surface includes a photoactive layer.

[0083] In these embodiments, the transferable electrode preferably comprises a metal-based conductive layer overlying the release surface of the release substrate, and an organic conductive layer, preferably a charge transport layer, more preferably a PEDOT-based conductive layer overlying the metal-based conductive layer.

[0084] The multi-layer composition of the optoelectronic device can include the defined layers, and in some embodiments may include one or more additional layers. For example, in some embodiments, the optoelectronic device further includes a second charge transport layer disposed over the flexible substrate, disposed between the at least one photoactive layer and the transferable electrode. In these embodiments, the electronic carrier substrate is a flexible substrate coated with a transparent conductive oxide coating; a first charge transport layer disposed over the flexible substrate; at least one photoactive layer overlying the first charge transport layer; a second charge transport layer disposed over the at least one photoactive layer; and Including, The receiving surface includes a second charge transport layer.

[0085] In these embodiments, the transferable electrode preferably comprises a metallic conductive layer overlying the release surface of the release substrate, and a carbonaceous (porous) conductive layer overlying the metallic conductive layer.

[0086] It should be appreciated that other suitable layers may also be included in the lay-up, depending on the desired optoelectronic device configuration.

[0087] As previously discussed, the first charge transport layer and the second charge transport layer can have any suitable composition. In an embodiment, at least one of the first charge transport layer or the second charge transport layer includes at least one hole transport layer, at least one electron transport layer. These layers can have various compositions depending on the desired optoelectronic device configuration as outlined in detail with respect to the second aspect of the invention. In an exemplary embodiment, at least one of the first charge transport layer or the second charge transport layer can be selected from various materials as discussed above. In an embodiment, the first charge transport layer or the second charge transport layer is selected from at least one of tin oxide, Spiro-OMeTAD, PPDT2FBT, or phenyl-C61-butyric acid methyl ester (PCBM) / ethoxylated polyethyleneimine (PEIE).

[0088] It should be noted that the composition of the first charge transport layer or the second charge transport layer may include one or more additives.

[0089] The photoactive layer may include a suitable photoactive composition. One exemplary photoactive layer includes at least one perovskite layer. It should be appreciated that the photoactive perovskite layer includes a light-absorbing perovskite semiconductor that is essentially composed of perovskite crystallites. As discussed later in this specification, the term "perovskite" as used herein refers to (a) a material having a three-dimensional crystal structure related to that of CaTiO3, or (b) a material comprising a layer of material, the layer having a structure related to that of CaTiO3. Perovskite materials can be represented by the formula [A][M][X]3, where [A] is at least one cation, [M] is at least one cation, and [X] is at least one anion.

[0090] In an embodiment, the transparent conductive oxide (TCO) coating is selected from at least one of tin-doped indium oxide (ITO), fluoride-doped tin oxide (FTO), doped zinc oxide such as aluminum-doped zinc oxide (AZO), or indium-doped cadmium oxide.

[0091] The flexible substrate preferably comprises a polymer, preferably a polymer film, preferably a polyethylene terephthalate (PET), polyethylene naphthalate (PEN), or ethylene tetrafluoroethylene (ETFE) film, more preferably a polyethylene terephthalate (PET) film.

[0092] The electronic carrier typically comprises a multi-layer flexible electronic device formed by the successive application of functional layers to a flexible substrate. In an embodiment, the electronic carrier substrate comprises: Providing a flexible substrate coated with a transparent conductive oxide coating; applying a first charge transport layer overlying the flexible substrate; applying at least one photoactive layer overlying the first charge transport layer; Optionally applying a second charge transport layer overlying the at least one photoactive layer; It is prepared by

[0093] Like the layers of electrodes, each layer of electron carriers has Casting, doctor blading, blade coating, bar coating, screen printing, inkjet printing, pad printing, knife coating, meniscus coating, slot die coating, gravure printing, reverse gravure printing, kiss coating, micro roll coating, curtain coating, slide coating, spray coating, flexography, offset printing, rotary screen printing, or dip coating. is applied to the subsequent layers using at least one of

[0094] The process of the present invention can be easily scaled up using a roll-to-roll process. The method of the present invention therefore preferably comprises a roll-to-roll printing electrode transfer method. The inventors have found that electrodes produced using this method perform well compared to electrodes produced using conventional vapor deposition electrode methods and are very competitive in terms of performance.

[0095] A fifth aspect of the invention provides an optoelectronic device formed using a method according to the fourth aspect of the invention. Optoelectronic devices can include a wide range of photoactive devices, such as photoelectric and photovoltaic devices, including but not limited to photoactive sensors, including photovoltaic cells, photodetectors, and the like. Thus, an optoelectronic device according to the invention can include a photoactive device, such as a photovoltaic cell, a photoactive sensor, or a light emitting device. In some embodiments, the optoelectronic device can be selected from a photodiode, a phototransistor, a photomultiplier, a photoresistor, a photodetector, a light sensitive detector, a solid state triode, a battery electrode, a light emitting device, a light emitting diode, a transistor, a solar cell, a laser, and a diode injection laser. The optoelectronic device preferably includes at least one of a photovoltaic cell or a photoactive sensor.

[0096] Optoelectronic devices or photoactive devices including a photoactive layer formed by the process of the present invention can be formed as an inverted structure or a conventional structure. For perovskite optoelectronic devices, a conventional structure is formed using a substrate having the following layers layered successively on its surface: a transparent conductive oxide (TCO) layer, followed by an electron transport layer, followed by a photoactive layer, followed by a hole transport layer, followed by a conductor layer (typically a metal). An inverted structure is formed using a substrate having the following layers layered successively on its surface: a transparent conductive oxide (TCO) layer, followed by a hole transport layer, followed by a photoactive layer, followed by an electron transport layer, followed by a conductor layer (typically a metal). The hole transport (p-type) layer can be any hole-conducting material with an appropriate valence band edge. For organic optoelectronic devices, a conventional structure is formed using a substrate having the following layers layered successively on its surface: a transparent conductive oxide (TCO) layer, followed by a hole transport layer, followed by an organic (BHJ) photoactive layer, followed by an electron transport layer, followed by a conductor layer (typically metal). An inverse structure is formed using a substrate having the following layers layered successively on its surface: a transparent conductive oxide (TCO) layer, followed by an electron transport layer, followed by an organic (BHJ) photoactive layer, followed by a hole transport layer, followed by a conductor layer (typically metal).

[0097] The transferable electrodes of the present invention can be applied to a variety of printed electronics, including flexible photovoltaic devices. Suitable photovoltaic devices include organic photovoltaic devices and perovskite photovoltaic devices.

[0098] The method / process and electrode of the present invention comprise: Printed electrodes for flexible photovoltaic elements, including thin film photovoltaic devices. Printed electronic sensors. Printed flexible electronics, including flexible optoelectronic devices such as OLEDs and diodes. The present invention can be applied to the manufacture of printed electronic devices.

[0099] The process for producing the electronic device of the present invention preferably comprises the following steps: Eliminates expensive / low throughput vacuum deposition of the top electrode. · It is suitable for roll-to-roll production and therefore can be easily scaled up. Producing high performance fully printed photovoltaic elements. provides the advantages of:

[0100] The present invention will now be described with reference to the accompanying drawing figures which illustrate particularly preferred embodiments of the invention. [Brief description of the drawings]

[0101] [Figure 1] 1A-1D are perspective views of a process for forming a flexible electronic device using transferable electrodes according to one embodiment of the present invention. [Diagram 2] 1 is a schematic diagram of layers of a flexible electronic device including a transferable electrode according to one embodiment of the present invention. [Diagram 3] 3 provides a side view of the flexible electronic device shown in FIG. 2 illustrating the constituent layers of the device. [Figure 4A] 1 is a photograph of an optoelectronic device according to an embodiment of the present invention with the exfoliation substrate already removed. [Figure 4B] 5 is a photograph of the optoelectronic device shown in FIG. 4 with the release substrate thereon removed from the transferable electrodes. [Diagram 5] FIG. 1 provides a schematic diagram of a first methodology for forming an optoelectronic device according to a first embodiment of the present invention, showing steps of (A) printing a layer of a carrier substrate (partially fabricated device), (B) a fully printed carrier substrate, (C) printing a layer of transferable electrodes, (D) a fully printed transferable electrode, (E) applying the transferable electrodes to the carrier substrate, (F) a formed optoelectronic device with a sacrificial release substrate attached, (G) removal of the sacrificial release substrate from the transferable electrodes, and (H) a final optoelectronic device. [Figure 6]FIG. 1 provides a schematic diagram of a second methodology for forming an optoelectronic device according to a first embodiment of the present invention, showing steps of (A) printing a layer of a carrier substrate (partially fabricated device), (B) a fully printed carrier substrate, (C) printing a layer of transferable electrodes, (D) a fully printed transferable electrode, (E) applying the transferable electrodes to the carrier substrate, (F) a formed optoelectronic device with a sacrificial release substrate attached, (G) removal of the sacrificial release substrate from the transferable electrodes, and (H) a final optoelectronic device. [Figure 7] FIG. 1 provides a schematic diagram of a third methodology for forming an optoelectronic device according to a first embodiment of the present invention, showing steps of (A) printing a layer of a carrier substrate (partially fabricated device), (B) a fully printed carrier substrate, (C) printing a layer of transferable electrodes, (D) a fully printed transferable electrode, (E) applying the transferable electrodes to the carrier substrate, (F) a formed optoelectronic device with a sacrificial release substrate attached, (G) removal of the sacrificial release substrate from the transferable electrodes, and (H) a final optoelectronic device. [Figure 8] 1 provides scanning electron microscope (SEM) images of a) Ag film and b) carbon film of the transferable electrodes taken prior to lamination transfer onto the PSC precursor stack. [Figure 9] 1 provides a graph showing sheet resistance measurements for various carbon film thicknesses taken prior to lamination transfer to a PSC precursor stack. [Figure 10] Illustrates a) JV curve graph, b) MPP tracking graph, and c) EQE and cumulative Jsc for Champion flexible PSC with printed DPD Ag / carbon electrode showing reverse and forward scans under 1 sun illumination, d) JV curve graphs for Champion PSC with printed DPD electrode and Champion PSC with evaporated Au electrode, and e) box plots of PCE results for PSCs with printed DPD or Au electrodes (insets (i) and (ii): device photographs). [Figure 11]Provides a) an illustrative diagram of a flexible encapsulation design used in operational stability testing of flexible PSCs with printed DPD electrodes; b) a graph of MPP tracking of a flexible PSC with printed DPD electrodes encapsulated with a flexible polymeric barrier material under continuous illumination in an ambient laboratory environment (inset (i): photo of encapsulated PSC); c) an illustrative diagram showing the device in convex (left) and concave (right) bending regimes showing the stress applied to the printed top electrode; and d) a graph of cyclic bending results comparing normalized PCE devices with printed DPD electrodes or evaporated Au electrodes. [Figure 12] Photographic images (a) of the in-house built bending fixture, and b) of the in-house built bending machine shown in (a) provide the 10 mm bending radius used for mechanical stability testing over 3000 bending cycles. [Figure 13] 13 is a graph illustrating normalized resistance results for printed DPD Ag / carbon layers under various bending regimes, measured using a four-point probe. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0102] The present invention provides methods for forming transferable thin-film electrode devices, transferable thin-film electrodes, and flexible electronic devices, such as optoelectronic devices, incorporating the transferable thin-film electrodes.

[0103] The transferable electrode device includes a flexible release substrate and one or more conductive layers on the flexible release substrate configured to interface with an electronic carrier substrate, In use, the flexible release substrate is separable from the transferable electrode after the electronic carrier substrate is adhered to the interface layer of the transferable electrode.

[0104] One embodiment of the transferable electrode 100 of the present invention is shown in Figures 1 to 4. The transferable electrode 100 is fabricated as a thin electrode film having a thickness that does not stand on its own unless it is supported on a release substrate 110. In this sense, the transferable electrode 100 is physically unstable, i.e., the thin electrode film cannot stand on its own.

[0105] The transferable electrode 100 is prepared by applying at least one layer of a conductive medium over a release surface of a release substrate 110 comprising a flexible polymer film, e.g., an anti-stick coating (as illustrated), to form a conductive layer thereon. The conductive layer is formed using a solution processing method in which the conductive composition is deposited as a layer using a wet method. The conductive medium (and solution process conductive composition) can have any composition suitable for use in solution printed flexible electronic devices, e.g., flexible optoelectronic devices. In an exemplary embodiment of the invention, the conductive medium comprises a flowable mixture of a metal-based composition, a carbonaceous conductive composition, and / or an organic conductive composition and a solvent, as previously discussed. The transferable electrode can be formed from a single conductive layer composition, or two or more conductive layer compositions. In the embodiment illustrated in Figures 1-4, the transferable electrode is a bilayer electrode including both carbonaceous and metallic conductive layers, where a layer of metallic conductive medium is applied to a release / carrier substrate 110 to form a first conductive layer 112, and a layer of carbonaceous, or organic, conductive material is applied to the first conductive layer to form a second conductive layer 114.

[0106] In this embodiment, the release substrate is described as comprising a flexible polymer, preferably a flexible polymer film, although it should be appreciated that it could equally comprise other flexible materials, such as paper or aluminum foil.

[0107] Each layer of applied conductive media (metallic conductive media and carbonaceous conductive material) is heat treated to remove the solvent from the layer. Once the conductive materials forming the electrode have been suitably heat treated and all solvent removed, the electrode 100 and peeled substrate film 110 arrangement is applied to an electronic carrier substrate 120, a partially prepared flexible electronic device. This involves applying pressure to press the electrode to a receiving layer of the electronic carrier substrate. In Figures 1 and 4, pressure is applied using a calendar press 130 including two opposing rollers 132 to press the electrode to the electronic carrier substrate 120.

[0108] The electronic carrier substrate 120 illustrated in Figures 1-4 includes a partially prepared flexible photovoltaic device. As best shown in Figures 2 and 3, the electronic carrier substrate 120 includes a flexible substrate (typically a flexible polymer film) coated with a transparent conductive oxide coating 140, a first charge transport layer 150 disposed over the flexible substrate 140, a subsequent photoactive layer 160 disposed over the first charge transport layer 150, and then an optional second charge transport layer 170 disposed over the photoactive layer 160. It should be appreciated that the multi-layer composition of the optoelectronic device can include defined layers, and in some embodiments may include one or more additional layers depending on the desired configuration of the flexible photovoltaic device 105.

[0109] Each layer of the transferable electrode 100 and the electronic carrier substrate 120 can be formed by one of many coating techniques known in the art, including casting, doctor blading, blade coating, bar coating, screen printing, inkjet printing, pad printing, knife coating, meniscus coating, slot die coating, gravure printing, reverse gravure printing, kiss coating, microroll coating, curtain coating, slide coating, spray coating, flexographic printing, offset printing, rotary screen printing, dip coating, direct or physical application, and the like. It should be recognized that a person skilled in the art can adopt a suitable technique to apply each layer based on techniques known in the art. In this sense, each layer of the transferable electrode 100, and preferably also each layer of the carrier substrate 120, is applied using a solution processing method.

[0110] The transferable electrode 100 is transferred to an electronic carrier substrate 120 using pressure. If the lower layer is a carbonaceous conductive composition 114, that layer 114 will tend to bond to the top layer of the device, the top charge transport layer 170 of the electronic carrier substrate 120 in the illustrated embodiment. Once through the calendar press 130, the anti-stick release substrate 110 can then be peeled off from the electrode stack, exposing the transferable electrode 100 and completing the fabrication of the flexible photovoltaic device 105. In this manner, fully printed, high performance flexible photovoltaic (PV) devices 105 can be produced using this method that is scalable using high throughput roll-to-roll processes.

[0111] In this novel method, the transferable electrode 100 is printed separately and heat treated (annealed) before being pressed onto the electronic carrier substrate 120 to avoid any unwanted interaction with the solvents in the lay-up of the electronic carrier substrate 120. Additionally, the transferable electrode 100 does not require further heat treatment after being pressed into the device, thereby avoiding degradation of some underlying layers of the electronic carrier substrate 120 that could occur if heat treatment were required.

[0112] This method also allows the thickness of the printed electrodes to be significantly reduced, improving the flexibility and density of the device.

[0113] As previously outlined and described, the conductive layer can have any suitable conductive composition.Similarly, as previously outlined and described, the layers of the electronic carrier substrate 120 can have any suitable composition.

[0114] In various embodiments of the illustrated flexible photovoltaic device 105, the photoactive layer 160 is a perovskite material. Those skilled in the art will recognize that perovskite materials can be represented by the formula [A][M][X]3, where [A] is at least one cation, [M] is at least one cation, and [X] is at least one anion. When a perovskite contains more than one A cation, the different A cations may be distributed regularly or irregularly across the A sites. When a perovskite contains more than one M cation, the different M cations may be distributed regularly or irregularly across the M sites. When a perovskite contains more than one X anion, the different X anions may be distributed regularly or irregularly across the X sites. The symmetry of perovskites containing more than one A cation, more than one M cation, or more than one X cation is lower than that of CaTiO3. Perovskites are crystalline compounds. Thus, a layer of a perovskite semiconductor without open pores typically consists essentially of perovskite crystallites. In a perovskite-based photoactive device, such as a photovoltaic cell, the photoactive layer may comprise an organic-inorganic perovskite structure semiconductor. However, it should be appreciated that in some embodiments, the photoactive layer may be all inorganic, for example CsPbI3.

[0115] As mentioned in the preceding paragraph, the term "perovskite" as used herein refers to (a) a material having a three-dimensional crystal structure related to that of CaTiO3, or (b) a material comprising a layer of material having a structure related to that of CaTiO3. Both of these classes of perovskites may be used in the device according to the invention, but in some circumstances it is preferred to use the first class of perovskites, (a), i.e., perovskites having a three-dimensional (3D) crystal structure. Such perovskites typically comprise a 3D network of perovskite unit cells without any separation between layers. On the other hand, the second class of perovskites, (b), comprises perovskites having a two-dimensional (2D) layered structure. Perovskites with a 2D layered structure may include layers of perovskite unit cells separated by (intercalated) molecules; an example of such a 2D layered perovskite is [2-(1-cyclohexenyl)ethylammonium]2PbBr4. 2D layered perovskites tend to have high exciton binding energy, which favors the generation of bound electron-hole pairs (excitons) under photoexcitation rather than free charge carriers. Bound electron-hole pairs may not be mobile enough to reach the p-type or n-type contacts where they can then migrate (ionize) and generate free charges. As a result, to generate free charges, the exciton binding energy needs to be overcome, which represents an energetic cost to the charge generation process, resulting in lower voltages and lower efficiencies in photovoltaic cells. In contrast, perovskites with a 3D crystal structure tend to have much lower exciton binding energy (on the order of thermal energy) and therefore can generate free carriers immediately following photoexcitation. Thus, the perovskite semiconductors used in the devices and processes of the present invention are preferably perovskites of the first class, (a), i.e. perovskites with a three-dimensional crystal structure, which is particularly preferred when the optoelectronic device is a photovoltaic device.

[0116] The term "thickness" used herein refers to the average thickness of a component of an electronic device. As mentioned above, the transferable electrode of the present invention is preferably a thin film electrode, which is so thin that it is not self-supporting. In an embodiment, at least one conductive layer has a dry layer thickness of 1 μm to 100 μm, preferably 10 to 80 μm, more preferably 20 to 60 μm, and even more preferably about 40 μm.

[0117] The release substrate 110 provides a surface (a release surface) to which the transferable electrode 100 is releasably affixed, affixed, or otherwise attached. In the embodiments described above, the release substrate 110 can be separated from the transferable electrode 100 after the carbonaceous conductive composition 114 of the transferable electrode 100 bonds to the topmost charge transport layer 170 of the electronic carrier substrate 120.

[0118] In various embodiments of the illustrated flexible photovoltaic device 105, the release / carrier substrate 110 includes an anti-stick surface such that the flexible release substrate can be easily separated from the transferable electrode by delamination therefrom. The anti-stick surface can be a surface of an anti-stick coating on the flexible release substrate. Suitable anti-stick coatings are generally polymers selected from the group consisting of low surface energy polymers, e.g., fluorinated polymers such as polytetrafluoroethylene (PTFE), and silicone polymers such as polydimethylsiloxane (PDMS). Alternatively, the flexible release substrate can include a free-standing film of a suitable low surface energy polymer, and the anti-stick surface is a surface of the film.

[0119] It should be appreciated that the release substrate 110 may equally include a low cohesion sacrificial layer sandwiched between the release substrate 110 and the conductive layer of the transferable electrode. As used herein, a low cohesion sacrificial layer is a layer that has intentionally weaker cohesion within it than the adhesion between and within other layers in the transferable electrode 100 and the electronic carrier substrate 120 in a multi-layer structure. The low cohesion sacrificial layer may be an inherently low cohesion layer, i.e., at room temperature, or may have a suitably low cohesion when activated. In either case, the flexible release substrate is preferentially detachable from the transferable electrode by breaking the low cohesion sacrificial layer. However, it will nevertheless be appreciated that the low cohesion sacrificial layer requires sufficient cohesive integrity and adhesive properties so that the flexible release substrate can adhere to and support the transferable electrode during fabrication and during transfer of the transferable electrode 100 to the electronic carrier substrate 120.

[0120] The transparent low cohesion sacrificial layer is preferably a very thin layer, for example having a thickness of less than 100 nm, or less than 50 nm, or less than 20 nm. In some embodiments, the low cohesion sacrificial layer is conductive due to the incorporation of conductive components such as metals, metal oxides, and conductive polymers or polymer composites (such as poly(3,4-ethylenedioxythiophene) polystyrenesulfonate, i.e., PEDOT:PSS). The inclusion of conductive components can advantageously mitigate any decrease in electrical conductivity through the surface of the first transparent conductive layer if residues of the low cohesion sacrificial layer remain on the layer following separation and removal of the flexible release substrate.

[0121] In some embodiments, the low cohesion sacrificial layer comprises a low cohesion organic non-polymeric solid, such as a wax. In some embodiments, the low cohesion sacrificial layer comprises an activatable adhesive. The activatable adhesive can be activated by any suitable external stimulus, such as heat or radiation, applied when necessary, to sufficiently reduce the cohesion of the sacrificial layer. Thus, the release substrate can be separated from the transferable electrode by activating the activatable adhesive by heat or radiation and breaking the low cohesion sacrificial layer.

[0122] In some embodiments, the activatable adhesive in the sacrificial layer is a heat-activatable adhesive, such as a thermoplastic polymer selected from the group consisting of ethylene-vinyl acetate (EVA) copolymer, polyethylene, polyethylene oxide (PEO), and polystyrene (PS). The thermoplastic polymer responds to the application of heat by melting or softening, thus reducing the cohesive strength of the sacrificial layer as required. Preferably, activation occurs at a temperature that can be achieved without damaging other layers in the device when interfacing / adhering (e.g., pressing) the transferable electrode 100 to the electronic carrier substrate 120. In some embodiments, the sacrificial layer is heat-activatable at a temperature in the range of 50° C. to 170° C., such as in the range of 90° C. to 140° C., to sufficiently reduce its cohesive strength.

[0123] In another embodiment, the activatable adhesive in the sacrificial layer is a photodepolymerizable polymeric composition, optionally including a suitable photoinitiator or photocatalyst. Examples include polymeric compositions selected from the group consisting of poly(phthalaldehyde) (PPHA) combined with a photoacid generator (PAG), poly(acetal) combined with a PAG, and polylactide (PLA) combined with TiO2. The photodepolymerizable polymeric composition responds to irradiation with a suitable wavelength of light by depolymerizing or decrosslinking, thus reducing the cohesive strength of the sacrificial layer as required.

[0124] Figures 5-7 illustrate three different methodological steps for forming flexible perovskite devices comprising transferable electrodes of the present invention. Flexible perovskite devices can be fabricated using a variety of processes, including readily scalable roll-to-roll (R2R) compatible printing and coating processes.

[0125] Methodology 1 (Figure 5): FIG. 5 illustrates a first embodiment of an electronic device, in this case a perovskite photovoltaic cell 205 (FIG. 5H), that can be fabricated using embodiments of the transferable electrodes of the present invention.

[0126] In a first step, an electronic carrier substrate, a partially fabricated flexible perovskite solar device 220 (without an outer electrode layer) is fabricated. As shown in FIG. 5A, a flexible substrate 240, such as PET, is prepared and coated with a transparent conductive oxide (TCO) coating 242, such as indium-tin-oxide (ITO). A first charge transport layer (CTL) 250 is then deposited on the substrate by reverse gravure or slot-die coating techniques. A photoactive perovskite layer 260 is deposited on top of this CTL 250 by slot-die coating. Following a short heat treatment (annealing) step at a temperature of at least 60° C., a second CTL 270 is slot-die coated on top of the perovskite film 260. This results in a partially fabricated flexible perovskite solar device 220, fully deposited up to the top CTL 270 (FIG. 5B).

[0127] Instead of directly depositing the top electrode on the CTL layer 270, a printed top electrode 200 is separately prepared on a release substrate 210. As shown in FIG. 5C, a release substrate 210 (such as a flexible polymer 210A such as PET with an anti-stick coating 211 such as polytetrafluoroethylene (PTFE) or silicone derivatives such as siloxane) is first fixed on a flat platform (not shown) and then uniformly coated on the surface with a metal-based paste (e.g., a highly conductive Ag-based paste) 212A. This can be done using a series of printing and coating methods such as doctor blading, blade coating, bar coating, screen printing, slot-die coating, inkjet printing, etc. Once coated, the release substrate 210 is transferred to a hot plate (not shown) to heat-treat / anneal the coated conductive film at a temperature of at least 100° C. to form a thin metal-based conductive film 212 (FIG. 5D). Following this annealing step, the metal layer coating film is transferred back to a flat platform (not shown) and a uniform layer of carbon-based / carbonaceous paste 214A is coated on top of the thin conductive film 212. Once coated, the release substrate 210 is transferred to a hotplate (not shown) to heat treat / anneal the coated conductive film at a temperature of at least 100° C. to form the carbon-based conductive film 214 (FIG. 5D). The annealing step of both the conductive and carbon-based pastes evaporates any solvent present that could otherwise enter the active layers of the flexible perovskite solar cell and cause degradation of the device. This results in a transfer device 202 that includes a bilayer flexible electrode 200 coated on the release substrate 210.

[0128] As illustrated in Figure 5E, the transfer apparatus 202 (release substrate 210 and bilayer flexible electrode 200) is then pressed onto the top CTL 270 of the partially fabricated flexible perovskite solar device 220. This can be accomplished by roll lamination techniques, for example using a calendar press, a uniaxial press, or an isostatic press, to form a release coated device 204 (Figure 5F).

[0129] In this embodiment, the carbon based conductive film 214 provides an interface conductive layer that directly engages and is attached (by pressing) to the receiving surface (top CTL 270) of the partially fabricated flexible perovskite solar device 220. The carbon based conductive film 214 provides a suitable layer that is configured to interface between the bilayer flexible electrode 200 and the partially fabricated flexible perovskite solar device 220.

[0130] Following pressing, the release substrate 210 (flexible polymer 210A with anti-stick coating 211) is removed, e.g., peeled off, from on top of the printed electrodes (Figure 5G), exposing the conductive film for electrical connection, resulting in the final flexible perovskite solar device 205.

[0131] Methodology 2 (Figure 6): FIG. 6 illustrates a second embodiment of an electronic device, in this case a perovskite photovoltaic cell 305 (FIG. 6H), that can be fabricated using an embodiment of the transferable electrode of the present invention.

[0132] In a first step, an electronic carrier substrate, a partially fabricated flexible perovskite solar device 320 (without the outer electrode layer and the CTL layer underneath) is fabricated. As shown in FIG. 6A, a flexible substrate 340 such as PET is prepared and coated with a transparent conductive oxide (TCO) coating 342 such as indium-tin-oxide (ITO). A first charge transport layer (CTL) 350 is then deposited on the substrate by reverse gravure or slot-die coating techniques. A photoactive perovskite layer 360 is deposited on top of this CTL 360 by slot-die coating. This results in a partially fabricated flexible perovskite solar device 320 that is fully deposited up to the top perovskite layer 360 (FIG. 6B).

[0133] Instead of depositing the top CTL layer and top electrode directly on the perovskite layer 360, a printed top CTL layer (organic conductor layer / film 314) and top electrode (metal-based conductive film 312) are separately prepared on a release substrate 310. As shown in FIG. 6C, the release substrate 310 (such as a flexible polymer 310A such as PET with an anti-stick coating 311 such as polytetrafluoroethylene (PTFE) or silicone derivatives such as siloxane) is first fixed on a flat platform (not shown) and then uniformly coated on the surface with a metal-based paste (e.g., a highly conductive Ag-based paste) 312A. This can be done using a series of printing and coating methods such as doctor blading, blade coating, bar coating, screen printing, slot-die coating, inkjet printing, etc. Once coated, the release substrate 310 is transferred to a hot plate (not shown) to heat-treat / anneal the coated conductive film at a temperature of at least 100° C. to form a thin metal-based conductive film 312 (FIG. 6D). Following this annealing step, the metal layer coating film is transferred back onto a flat platform (not shown) and a uniform layer of an organic conductor (e.g., PEDOT, or PEDOT:PSS solution) 314A is coated on top of the thin conductive film 312. Once coated, the release substrate 310 is transferred to a hotplate (not shown) to heat treat / anneal the coated conductive film at a temperature of at least 80° C. to form the organic conductive film 314 (FIG. 6D). During the annealing step, both conductive pastes evaporate any solvent present. This results in a transfer device 302 that includes a bilayer flexible electrode 300 coated onto the release substrate 310.

[0134] As illustrated in Figure 6E, the transfer apparatus 302 (release substrate 310 and bilayer flexible electrode 300) is then pressed onto the top perovskite layer 360 of a partially fabricated flexible perovskite solar device 320. This can be accomplished by roll lamination techniques (e.g., calendar pressing, uniaxial pressing, or isostatic pressing) to form a release coated device 304 (Figure 6F).

[0135] In this embodiment, the organic conductive film 314 provides an interface conductive layer that directly engages and is attached (by pressing) to the receiving surface (top perovskite layer 360) of the partially fabricated flexible perovskite solar device 320. The organic conductive film 314 provides a suitable layer that is configured to interface between the bilayer flexible electrode 300 and the partially fabricated flexible perovskite solar device 320.

[0136] Following pressing, the release substrate 310 (flexible polymer 310A with anti-stick coating 311) is removed, e.g., peeled off, from on top of the printed electrodes (Figure 6G), exposing the conductive film for electrical connection, resulting in the final flexible perovskite solar device 305.

[0137] Methodology 3 (Figure 7): Barrier encapsulation is useful for protecting photovoltaic devices from degradation due to interaction of the device functional layers with moisture and oxygen in the ambient atmosphere. Direct deposition of barrier materials onto printed PV devices is one of the methods of applying a barrier layer to the device. However, if the barrier formulation contains any solvent that reacts with the functional layer, direct deposition is not possible. Using the method of the present invention, a barrier encapsulant layer can be effectively applied to the device either as is or even as a multilayer system containing the encapsulant, Ag electrode, and carbon electrode.

[0138] FIG. 7 illustrates a third embodiment of an electronic device, in this case a perovskite photovoltaic cell 405 (FIG. 7H), that can be fabricated using transferable electrode embodiments of the present invention.

[0139] In a first step, an electronic carrier substrate, a partially fabricated flexible perovskite solar device 420 (without an outer electrode layer) is fabricated. As shown in FIG. 7A, a flexible substrate 440, such as PET, is prepared and coated with a transparent conductive oxide (TCO) coating 442, such as indium-tin-oxide (ITO). A first charge transport layer (CTL) 450 is then deposited on the substrate by reverse gravure or slot-die coating techniques. A photoactive perovskite layer 460 is deposited on top of this CTL 450 by slot-die coating. Following a short thermal treatment (annealing) step at a temperature of at least 100° C., a second CTL 470 is slot-die coated on top of the perovskite film 460. This results in a partially fabricated flexible perovskite solar device 420, fully deposited up to the top CTL 470 (FIG. 7B).

[0140] Instead of depositing the top electrode directly on the CTL layer 470, a printed top electrode 400 is separately prepared on a release substrate 410. As shown in FIG. 5C, a release substrate 410 (such as a flexible polymer 410A such as PET with an anti-stick coating 411 such as polytetrafluoroethylene (PTFE) or silicone derivatives such as siloxane) is first fixed on a flat platform (not shown) and then uniformly coated on the surface with a barrier material formulation 415A, e.g., ethylene-vinyl acetate (EVA). This can be done using a series of printing and coating methods, e.g., doctor blading, blade coating, gravure coating, reverse gravure coating, bar coating, screen printing, slot-die coating, inkjet printing, etc. Once coated, the release substrate is transferred to a hot plate (not shown) to heat-treat / anneal the coated barrier film at a temperature of at least 60° C. to form a barrier film 415 thereon (FIG. 7D). Following this annealing step, the film is transferred back to a platform (not shown) and a uniform layer of metal-based paste (e.g., highly conductive Ag-based paste) 412A is applied on top of the barrier film 415. This can be done using a series of printing and coating methods, such as doctor blading, blade coating, bar coating, screen printing, slot die coating, inkjet printing, etc. Once coated, the release substrate 410 is transferred to a hotplate (not shown) to heat treat / anneal the coated conductive film at a temperature of at least 60° C. to form a thin metal-based conductive film 412 thereon (FIG. 7D). Following this annealing step, the metal layer coating film is transferred back to a flat platform (not shown) and a uniform layer of carbon-based / carbonaceous paste 414A is coated on top of the thin conductive film 412. Once coated, the release substrate 410 is transferred to a hotplate (not shown) to heat treat / anneal the coated conductive film at a temperature of at least 60° C. to form a carbon-based conductive film 414 (FIG. 7D).The annealing step of both the conductive and carbon-based pastes evaporates any solvents present that could otherwise enter the active layers of the flexible perovskite solar cell and result in degradation of the device. This results in a transfer device 402 that includes a bilayer flexible electrode 400 coated on a barrier film 415 and a release substrate 410.

[0141] As illustrated in Figure 7E, the transfer apparatus 402 (exfoliation substrate 410, barrier film 415, and bilayer flexible electrode 400) is then pressed onto the top CTL 470 of the partially fabricated flexible perovskite solar device 420. This can be accomplished by roll lamination techniques (e.g., calendar pressing), uniaxial pressing, or isostatic pressing to form a release coated device 404 (Figure 7F).

[0142] In this embodiment, the carbon based conductive film 414 provides an interface conductive layer that directly engages and is attached (by pressing) to the receiving surface (top CTL 470) of the partially fabricated flexible perovskite solar device 420. The carbon based conductive film 414 provides a suitable layer that is configured to interface between the bilayer flexible electrode 200 and the partially fabricated flexible perovskite solar device 420.

[0143] Following pressing, the release substrate 410 (flexible polymer 410A with anti-stick coating 411) is removed, e.g., peeled off, from on top of the barrier film 415 (Figure 7G), exposing the conductive film for electrical connection, resulting in the final flexible perovskite solar device 405.

[0144] As discussed above with respect to the first embodiment illustrated in Figures 1-4, it should be appreciated that each of the release substrates 210, 310, and 410 described and illustrated may equally include an activatable adhesive that can be activated, for example by heat or radiation, to separate the transferable electrodes from the release substrate; or, as described above, a low cohesion sacrificial layer sandwiched between the flexible release substrate and the transferable electrodes, which has an inherently low cohesion or has a low cohesion when activated such that the flexible release substrate is separable from the transferable electrodes by breaking the low cohesion sacrificial layer. It should be appreciated that the use of these types of release layers equally results in a transferable electrode 100 that can be transferred and interfaced / adhered to the electronic carrier substrate 220, 320, and 420 using applied pressure and removed using an appropriate removal technique applicable to that release substrate configuration. EXAMPLES

[0145] Example 1 Thin-film perovskite photovoltaic electrodes material The conductive Ag paste for the printed electrodes was purchased from DuPont (PV416 conductor paste). The paste typically consists of Ag particles, binder material, and solvent. Propylene glycol methyl ether acetate (PGMEA) was used as the paste thinner material. The thermoplastic carbon paste was a commercial carbon paste (DM-CAP-4701S) purchased from Dycotec Materials, UK.

[0146] The electron transport layer (ETL), aqueous SnO2 nanoparticle dispersion, was synthesized by a microwave-assisted synthesis route using a precursor of tin(IV) chloride pentahydrate (SnCl4·5H2O, 98%, Alfa Aesar Co.) in a mixture of EtOH / H2O (50% v / v). The nanoparticles were synthesized using a Biotage Initiator Classic microwave reactor (400 W) and the reaction was carried out at 100 °C for 30 min. The solid content of the SnO2 dispersion is about 4 wt%. A 72.66 mg solution of 2,2',7,7'-tetrakis-(N,N-di-4-methoxyphenylamino)-9,9'-spirobifluorene (Spiro-OMeTAD, Luminescence Technologies Corp.) in 1 mL of chlorobenzene (Sigma-Aldrich) was mixed with 18 μL of lithium bis(trifluoromethanesulfonyl)imide (LiTFSi, Sigma-Aldrich) stock solution (520 mg of LiTFSI in 1 mL of acetonitrile), 30 μL of 4-tert-butylpyridine (TBP, Sigma-Aldrich), and 29 μL of tris(2-(1H-pyrazol-1-yl)-4-tert-butylpyridine)-cobalt(III) tris(bis(trifluoromethylsulfonyl)imide)) (FK209, Luminescence Technologies Corp.) to prepare a 100% 100% 100% 15 ... A hole transport layer (HTL) solution was prepared by adding lead iodide (PbI2, Tokyo Chemical Industry Co.), formamidinium iodide (CH(NH2)2I, FAI, Greatcell Solar), methylammonium bromide (MABr, Greatcell Solar), and lead bromide (PbBr, Alfa Aesar) in 31 mL of anhydrous DMF and DMSO (4:1 v / v) to achieve a final solution concentration of 1.4 M. 34 μL of cesium iodide (CsI, Sigma-Aldrich) in DMSO (1.5 M) was added to the precursor solution and left stirring at 65° C. for 60 min in a nitrogen-filled glove box.

[0147] methodology The printed flexible electrodes illustrated and described in connection with Figures 1, 4(A) and 4(B) were fabricated directly on a flexible release substrate comprising a PET polymer sheet 110. The film release mechanism is due to an anti-stick thin silicone coating on one side of the polymer sheet 110, which results in very low adhesion properties. First, the release substrate was fixed onto a flat platform and then the surface was uniformly coated with Ag paste (PV416 conductor paste, Dupont) using doctor blading.

[0148] Once coated, the exfoliated substrate was transferred to a hotplate and the Ag film was annealed for 2 minutes at 135° C. Following this annealing step, the film was transferred back to the platform and a uniform layer of carbon paste (Dycotec (DM-CAP-4701S)) was deposited on top of the thin Ag film by the same doctor blading method.

[0149] A second hotplate anneal step at 135° C. for 5 minutes was applied. The anneal steps of both the Ag and carbon pastes are important to evaporate any solvents present that could otherwise enter the active layers of the solar device and result in rapid degradation of the device.

[0150] Thermal treatment of the Ag- and carbon-based coatings prior to contact with the R2R fabricated PSC precursor stack was important to avoid possible solvent diffusion into other device functional layers, which could lead to rapid degradation of the device.

[0151] The resulting multilayer flexible electrode was then pressed into a partially formed perovskite photovoltaic device (flexible PSC precursor stack, described below) having the configuration illustrated in Figure 5B by feeding both films between the rollers 132 of a calendar press 130. In this process, the carbon film bonds to the top CTL layer 270 of the photovoltaic device 220. The anti-stick release substrate 110 is then removed to expose the top Ag thin film electrode.

[0152] A flexible PSC precursor stack was prepared separately from the Ag / carbon electrode by sequential deposition of each functional layer using an easily scalable R2R coating technique, namely slot-die coating and reverse gravure coating. The perovskite layer and 2,2',7,7'-tetrakis-(N,N-di-4-methoxyphenylamino)-9,9'-spirobifluorene (Spiro-OMeTAD) HTL were deposited by slot-die coating, whereas the SnO2ETL was deposited using reverse gravure coating since better solution wetting and more uniform films can be achieved.

[0153] PSC device fabrication was performed entirely in ambient laboratory conditions (17–21 °C, 30–60% RH). R2R coating of SnO2 ETL, perovskite layer, and Spiro-OMeTAD HTL was performed on a Minilab™ or Minilab Deluxe™ R2R coater (Yasui Seiki Co., Ltd.). First, SnO2 was coated on the TCE side of a PET / TCE substrate (OC50, Meko Print Co., Ltd.) using a reverse gravure coating method (roller speed of 13 rpm, web speed of 0.2 m min-1, coating width of 11.5 mm), followed by passing over an in-line hotplate at 135 °C for approximately 10 s. The PET / TCO / SnO2 film was then subjected to R2R infrared treatment for 8 min using an Orthotec R2R machine. The perovskite solution was then coated onto the SnO2 film in a slot die (flow rate of 12 μL min-1, 0.3 m min -1The film was then quickly passed over a hot plate at 135 °C for approximately 5 s. The PET / TCE / SnO2 / perovskite film was then unwound and slot-die coated (15 μL min -1 The Spiro-OMeTAD solution was deposited by a flow rate of 0.1 m / min, line speed of 0.3 m / min, and coating width of 6 mm. For flexible PSCs with printed electrodes, the PET / TCE / SnO2 / perovskite / Spiro-OMeTAD film (PSC precursor stack) was cut into 10 cm long sections and passed through a calendar press (Minder-Hightech MD-Jr100; feed rate of 0.4 m / min) together with the printed Ag / carbon stack to complete the PSC device. The roller gap was measured by two electronic distance sensors (Yueqing instrument co.) and a thickness gauge stick (100B-17, Jinghua). For flexible PSCs with evaporated electrodes, a shadow mask was used to measure the thickness of the 0.2 cm 2 The active device area was defined and an 80 nm thick Au layer was deposited by thermal evaporation.

[0154] PSCs were fabricated using a conventional nip design; PET / TCE / SnO2 / Cs0.05FA0.81MA0.14Pb(I0.83Br0.17)3 / Spiro-OMeTAD / carbon / Ag.

[0155] Device characterization Characterization of all devices was performed in ambient laboratory atmosphere (17-21 °C, 40-60% RH). Current density-voltage (JV) measurements were performed using a class ABA solar simulator (Newport Oriel Sol2A, xenon lamp source). The solar simulator was run at 1-sun (1000 W m) using a certified reference cell (Enlitech, certified by Enlitech according to IEC60904-1:2006 with KG-2 filter) and a source meter (Keithley 2400). -2 ) was calibrated for AM1.5G illumination. A shadow mask was used to define the cell active area of ​​0.08 cm2. 20 mV s -1 JV measurements were performed in forward (increasing forward bias) and reverse (decreasing forward bias) scan directions over a voltage range of -0.2V to 1.2V at scan rates. Light Beam Induced Current (LBIC) images were recorded using a commercial LBIC system from InfinityPV. External Quantum Efficiency (EQE) measurements were performed using an IPCE measuring instrument (PEC-S20) from Peccell Technologies Inc. Operational stability was characterized by maximum power point (MPP) tracking using a sourcemeter (Keithley2400) under continuous illumination using an LED solar simulator light source (Candlelight systems) calibrated to 1 sun intensity illumination using the previously mentioned reference cell. Mechanical stability of the devices was characterized by using an in-house bending machine. Four-point probe measurements were taken in ambient laboratory atmosphere using a Jandel 4-point probe instrument and a Jandel RM3000 testing unit.

[0156] Consideration A good interfacial contact between the carbon film of the printed electrode and the HTL must be established for optimal PSC efficiency. In this work, good contact was achieved by passing the PSC precursor stack together with the printed Ag / carbon stack through a calendar press, as illustrated in Figure 1. The applied pressure was adjusted by varying the distance between the two rollers of the calendar press, which was monitored using two electronic sensors with an accuracy of 10 μm and a thickness gauge bar. The applied pressure, P, was determined by measuring the total thickness of the PSC precursor stack and the printed electrode stack before lamination, h1, as well as the distance between the two rollers of the calendar press, h2, according to equation (1). comp was calculated as a percentage. P comp =((h1-h2) / h1)×100%(1)

[0157] P between 12% and 60% comp The performance of the PSC devices was monitored as a function of applied pressure. It was found that 12% applied pressure was the lowest value required to achieve adequate adhesion between the printed carbon layer and the HTL of the PSC precursor stack, with the 17% and 20% variants giving the best performing devices.

[0158] The thickness of the bilayer electrode was also optimized to facilitate efficient charge transport and allow a high degree of flexibility. As shown in Figure 8(a), the Ag film is composed of densely packed Ag particles, which aids in charge collection and lateral charge transport to the electrical contacts. The optimized Ag film thickness of about 20 μm provides high electrical conductivity (approximately 50 mΩ). -1 ), and has been found to exhibit good mechanical flexibility to withstand repeated bending stresses.

[0159] Furthermore, the macroporous carbon film (Figure 8b) was found to be important in establishing strong interfacial contact with the receiving PSC precursor stack. Without this carbon interlayer, the printed Ag electrode was found to easily delaminate from the PSC precursor stack. The carbon film thickness affects both its flexibility and its electrical conductivity.

[0160] The sheet resistance for various carbon film thicknesses, as illustrated in FIG. 9, demonstrated an inverse relationship between film thickness and conductivity. Carbon thicknesses below 15 μm were also found to result in an exponential increase in sheet resistance. Conversely, it was found that if the carbon film was too thick (approximately 70 μm), the film would often tear or break upon bending and thus be unsuitable for this application. Therefore, the carbon film thickness was optimized to balance two crucial performance factors: conductivity and flexibility. The carbon dry film thickness (before transferring to the PSC precursor stack) was varied from 5 to 70 μm, and it was found that if the carbon layer was too thin (≦5 μm), poor interfacial contact was observed, resulting in reduced charge carrier collection and therefore poorer PSC device performance. For carbon film thicknesses between 10 and 50 μm, there was only a slight difference in the PSC device performance and all electrodes showed excellent electrode adhesion to the PSC precursor stack. While some devices still showed high performance for carbon films about 70 μm thick, the thick bilayer electrodes were significantly more brittle and prone to tearing and delamination during transfer to the PSC precursor stack. Balancing the factors of flexibility and conductivity, an optimized carbon film thickness of 30-40 μm was adopted.

[0161] Optimized PSC performance In Fig. 10a, the JV curves in the forward and reverse scan directions are presented along with the P-V parameters for the fully printed R2R fabricated Champion flexible PSC. 2 The champion device exhibited a PCE of 16.7% in the reverse scan direction (V = 1.17 V, J = 20.9 mA cm). 2 , FF=68.1%). We believe this result represents the highest efficiency recorded to date for a R2R-fabricated flexible PSC produced by non-vacuum deposition of all functional layers, except for TCE. The forward JV scan exhibits minimal hysteresis, with a PCE of 16.0% (Voc=1.17 V, Jsc=21.5 mA cm). 2, FF=63.7%). Maximum power point (MPP) tracking of the champion PSC with printed DPD Ag / carbon electrodes (Fig. 10b) shows a stable PCE of 16.0% for more than 80 s under continuous 1 sun illumination. Furthermore, the external quantum efficiency (EQE) and cumulative Jsc (Fig. 10c) show a wide range of optical absorption in the visible wavelength range, reaching approximately 20 mA cm -2 Confirm the Jsc.

[0162] As a control, a flexible device with evaporated Au electrodes was also fabricated from the same batch of PSC precursor stack. A comparison of the JV curves and PV parameters of the champion PSC with evaporated Au electrodes and that with printed DPD electrodes is shown in Figure 10d. The best Au electrode device showed a PCE of 17.4% in the reverse scan (Voc = 1.15 V, Jsc = 21.6 mA cm). -2 , and FF=69.8%), only slightly higher than the champion PSC with printed DPD electrodes, marking a record PCE for the R2R coated flexible PSC with evaporated Au electrodes. The reproducibility of the DPD fabrication method developed in this work is demonstrated in the box plots of Fig. 10e in comparison to the Au electrode devices. The PSC with printed DPD electrodes shows remarkable reproducibility, surpassed in performance only by some evaporated Au electrode PSCs. This slightly lower performance is at least in part attributable to the lack of reflection of the remaining transmitted incident light from the printed Ag / carbon electrode back to the perovskite layer compared to the highly reflective Au electrodes.

[0163] Operation and Mechanical Stability The operational stability of the flexible R2R fabricated PSCs produced in this work was investigated under MPP conditions with 1 sun irradiation in ambient laboratory environment. The PSCs were encapsulated in a flexible polymeric barrier material to protect them from degradation due to ambient moisture and oxygen. Prior to encapsulation, the PSCs and barrier materials were all appropriately preconditioned to mitigate the risk of moisture and oxygen outgassing. The encapsulation design is illustrated in Figure 11a. A 200 nm thick Ag pattern was evaporated onto the back barrier film to enable electrical contact with the device. An electrically conductive adhesive tape (conductive adhesive) was used to improve the electrical connection between the printed Ag / carbon electrodes and the evaporated Ag pattern. A photograph of the fully encapsulated PSC device is shown in the inset of Figure 11b. As shown in Figure 11b, under continuous irradiation with 1 sun intensity in ambient laboratory atmosphere (21 °C, 40-60% RH), the PSCs showed negligible decrease in PCE after 24 h of MPP tracking. The slight variations seen in the PCE are due to sporadic flickering of the irradiating lamp throughout the test period. Cyclic bending fatigue tests were performed to evaluate the mechanical robustness of the R2R fabricated PSC devices and compare the printed DPD electrodes to a control PSC with evaporated Au electrodes. Bending tests were performed on unencapsulated devices in an ambient laboratory environment using an in-house built bending fixture (Figure 12). The devices were subjected to convex and concave bending with a bending radius of 10 mm. These bending regimes applied tensile (convex) or compressive (concave) stress to the electrodes, and one cycle represents the sequence: flat → bend → flat.

[0164] A reference device was used to evaluate the stability of the device when stored in an ambient environment for the duration of the bending test, as represented by the gray line in FIG. 11d. After 3000 bending cycles, there were no visible signs of damage or delamination of the printed electrodes, indicating good adhesion between the carbon and Spiro-OMeTAD layers. As can be seen in FIG. 11d, the PSC device with the printed DPD electrodes exhibited remarkable mechanical robustness, maintaining more than 90% of its initial PCE after 3000 convex bending in an ambient laboratory environment. This is directly comparable to the Au electrode PSC, which maintained about 93% of its initial PCE after the same number of convex bendings.

[0165] A slightly greater degradation was observed when the devices were subjected to concave bending. PSCs with printed DPD or evaporated Au electrodes showed nearly identical performance after 3000 concave bending cycles, maintaining just under 80% of their initial PCE. To further explore the cause of this degradation, a four-point probe was used to measure the resistance of the printed DPD electrodes (Figure 13). Concave bending was found to cause more damage to the electrodes, resulting in an increase in sheet resistance, especially under extreme bending (5 mm radius). While for convex bending there was only a slight increase in sheet resistance between 10 mm and 5 mm radii, a greater than 350% increase is observed when the electrodes were subjected to only 500 concave bending cycles at 5 mm radius. It is hypothesized that this increase in resistance with concave bending contributes to the observed decrease in PCE seen in mechanical fatigue tests. Despite this, not only do the PSCs with printed DPD electrodes exhibit mechanical robustness comparable to that of the PSCs with evaporated Au electrodes, but there are no signs of delamination or film damage for the printed devices, even under a 5 mm radius bending regime.

[0166] Example 2 Testing different materials / inks The method described in Example 1 was carried out using different carbon paste compositions as listed in Table 1. All carbon pastes tested showed good lamination adhesion.

[0167] [Table 1]

[0168] Example 3 Trial of different charge transport materials The method described in Example 1 was carried out using different charge transport material compositions as listed in Table 2.

[0169] Table 2 shows that with all the tested materials, a series of organic charge transport materials can also be used and work satisfactorily from the lamination and adhesion standpoint. Poor lamination and some delamination was only observed when no charge transport material was used in the device layup and instead, the metallic Ag-based and carbon film bilayer electrodes taught in Example 1 were simply pressed onto the perovskite layer.

[0170] The different materials were produced as follows: Spiro-OMeTAD with additive: The following solution was prepared and coated onto the perovskite photoactive layer: 18 μL of lithium bis(trifluoromethanesulfonyl)imide (LiTFSi, Sigma-Aldrich) stock solution (520 mg of LiTFSI in 1 mL of acetonitrile), 30 μL of 4-tert-butylpyridine (TBP, Sigma-Aldrich), and 29 μL of tris(2-(1H-pyrazol-1-yl)-4-tert-butylpyridine)-cobalt(III) tris(bis(trifluoromethylsulfonyl)imide)) (FK209, Luminescence Technologies 72.66 mg of 2,2',7,7'-tetrakis-(N,N-di-4-methoxyphenylamino)-9,9'-spirobifluorene (Spiro-OMeTAD, Luminescence Technologies Corp.) in 1 mL of chlorobenzene (Sigma-Aldrich) before adding a stock solution (300 mg of FK209 in 1 mL of acetonitrile). Spiro-OMeTAD without additives: The following solution was prepared and coated onto the perovskite photoactive layer: 72.66 mg of 2,2',7,7'-tetrakis-(N,N-di-4-methoxyphenylamino)-9,9'-spirobifluorene (Spiro-OMeTAD, Luminescence Technologies Corp.) in 1 mL of chlorobenzene (Sigma-Aldrich). PPDT2FBT with additive: The following solution was prepared and coated onto the perovskite photoactive layer: 10 mg of poly[(2,5-bis(2-hexyldecyloxy)phenylene)-alt-(5,6-difluoro-4,7-di(thiophen-2-yl)benzo[c][1,2,5]-thiadiazole)] (PPDT2FBT, 1-Material Cobalt(III) tris(bis(trifluoromethylsulfonyl)imide)) (FK209, Luminescence Technologies Corp.) stock solution (300 mg of FK209 in 1 mL of acetonitrile) was added. · PPDT2FBT without additives: The following solution was prepared and coated onto the perovskite photoactive layer: 10 mg of poly[(2,5-bis(2-hexyldecyloxy)phenylene)-alt-(5,6-difluoro-4,7-di(thiophen-2-yl)benzo[c][1,2,5]-thiadiazole)] (PPDT2FBT, 1-Material Incorporated) was dissolved in 1 mL of chlorobenzene. PC 61 Organic photovoltaic (OPV) active layer composed of a bulk heterojunction blend of BM (Ossila) and P3HT (Merck). ·PCBM / PEIE: The following solutions were prepared and coated onto the perovskite photoactive layer: 12 mg / mL phenyl-C61-butyric acid methyl ester (PC61BM, Ossila) was dissolved in chlorobenzene (Sigma-Aldrich) and filtered through a 0.22 μL polytetrafluoroethylene (PTFE) filter. 3 μL mL-1 ethoxylated polyethyleneimine (PEIE, Sigma-Aldrich) was diluted in anhydrous isopropanol (IPA, Sigma-Aldrich) and stirred for 1 h at room temperature.

[0171] [Table 2]

[0172] Example 4 Transfer of carbon film electrodes The method described in Example 1 was followed, but only with a uniform layer of carbon paste (commercially available carbon paste Dycotec 4701s, Dycotec Materials Ltd, UK) deposited on top of the anti-stick thin coating of the release substrate using a doctor blade technique. The carbon paste is then annealed as described in Example 1.

[0173] Through trial, a transferable electrode having a carbon-based electrode layer was found to have good adhesion and lamination when pressed onto a partially formed perovskite photovoltaic device as described in Example 1. However, the performance of the final photovoltaic device was significantly lower than the device with the conductive Ag paste produced in Example 1. This difference was believed to be a result of the Ag paste providing a key role in providing high conductivity for the lateral flow of charge to the electrical contacts.

[0174] Example 5 Transfer of Ag film electrode The method described in Example 1 was followed, but with only a uniform layer of Ag paste (commercially available Ag paste (PV416, Dupont) deposited on top of the anti-stick thin coating of the release substrate using a doctor blade technique. The Ag paste is then annealed as described in Example 1. No carbon paste was coated on top of the Ag conductive layer.

[0175] By removing the carbonaceous film, the electrode design is simplified to only have a single layer metal-based electrode. Through trial, it has been found that a transferable electrode with an Ag-based electrode layer has good adhesion and lamination when pressed onto a partially formed perovskite photovoltaic device as described in Example 1. However, while some devices were functional, some of the formed devices exhibited short circuits. This was attributed to the hard Ag particles penetrating the soft layers of the device during lamination, shorting the device. Therefore, the inclusion of a carbonaceous / organic conductor layer can act as a buffer between the Ag electrode layer and the upper layers of the partially formed perovskite photovoltaic device, preventing the penetration of these particles. Thus, this macroporous carbon layer plays an important role in forming an intermediate layer between the PSC precursor stack and the conductive printed Ag layer.

[0176] Example 6 Transferable electrode with sacrificial layer A coating composition for preparing the sacrificial layer was prepared by mixing 10 ml of a commercially available 1.3-1.7% PEDOT:PSS aqueous solution (Clevios AI 4083, Heraeus), 200 mg of polyethylene oxide (PEO), a water-soluble low melting polymer (molecular weight 100 000 Daltons, melting point 65 °C), and 10 ml of 2-propanol. The sacrificial layer was produced by applying this mixture to a roll of uncoated polyethylene terephthalate (PET) film by roll-to-roll slot die coating. At room temperature, 1 μl / cm 2The mixture was deposited in a continuous strip 25 mm wide with a solution loading of 1000 g (hence a wet film thickness of approximately 10 microns) and then dried for 30 seconds at 130°C. The dried film, which was non-tacky at room temperature, became soft and tacky when heated above 80°C. In a Scotch tape test, the tape adhered firmly at room temperature but not at 80°C. o C. After removal, the sacrificial layer remained on the PET film based on visual inspection.

[0177] A transparent conductive layer was then produced by applying a commercially available 1% PEDOT:PSS aqueous solution (S315, Agfa) by roll-to-roll slot die coating onto the sacrificial layer at a speed of 0.3 m / min and 3.8 μl / cm 2 The PEDOT:PSS solution was deposited in a continuous strip 13 mm wide with a loading of 0.1 μm (hence a wet film thickness of about 38 microns) and dried for 30 seconds at 130° C. The sheet resistance of the transparent conductive layer was about 80 ohms / sq. This produced a transferable electrode.

[0178] The resulting multi-layer flexible electrode could then be configured to be pressed into a partially formed perovskite photovoltaic device, having the configuration illustrated in FIG. 6B, by feeding both films between the rollers 132 of a calendar press 130.

[0179] The separability of the transferable electrodes and the resulting multilayer photovoltaic devices from the release substrate was investigated by a Scotch tape test at 80 °C. The devices were easily released from the PET substrate by heat-activated fracture of the sacrificial layer. After removal of the PET film, the sheet resistance of the exposed transparent conductive layer was about 90-100 ohms / sq.

[0180] PEDOT:PSS was included in the sacrificial layer for several reasons. First, it overcame the dewetting problem encountered when roll-to-roll slot-die coating a solution of PEO alone. Second, the inclusion of conductive PEDOT:PSS is believed to mitigate the impact of sacrificial layer residues on the conductivity of the transparent conductive layer.

[0181] Those skilled in the art will appreciate that the invention described herein is susceptible to variations and modifications in addition to those specifically described, and it is understood that the invention includes all such variations and modifications that fall within the spirit and scope of the invention.

[0182] The terms "comprise", "comprises", "comprised" or "comprising", when used in this specification (including the claims), should be interpreted as specifying the presence of stated features, integers, steps, or components, but not excluding the presence of one or more other features, integers, steps, components, or groups thereof. [Explanation of symbols]

[0183] 100 electrodes / transferable electrodes 105 Flexible Photovoltaic Devices 110 PET polymer sheet / anti-stick release substrate / carrier substrate / release substrate film 112 First conductive layer 114 Second conductive layer / carbonaceous conductive composition 120 Electronic Carrier Board 130 Calendar Press 132 Roller 140 Flexible substrate / transparent conductive oxide coating 150 First charge transport layer 160 Photoactive layer 170 Second charge transport layer 205 Final flexible perovskite solar device 210 Peeling substrate 210A Flexible Polymer 211 Anti-stick coating 212 Thin metallic conductive films 212A Metallic paste 214A Carbon-based / carbonaceous paste 220 Flexible Perovskite Solar Devices 240 Flexible PCB 242 Transparent Conductive Oxide (TCO) Coating 250 First charge transport layer (CTL) 260 Photoactive Perovskite Layer 270 Second CTL 300 Double-layer flexible electrode 302 Transcription device 304 Release coated devices 310 Peeling substrate 310A Flexible Polymer 311 Anti-stick coating 312 Metallic conductive film 312A Metallic paste 314 Organic conductive film 314A Organic Conductor 320 Flexible Perovskite Solar Devices 340 Flexible PCB 342 Transparent Conductive Oxide (TCO) Coating 350 First charge transport layer (CTL) 360 Upper perovskite layer 400 Printed top electrode / double layer flexible electrode 402 Transcription device 404 Release coated devices 410 Peeling substrate 410A Flexible Polymer 411 Anti-stick coating 412 Metallic conductive film 412A Metallic paste 414 Carbon-based conductive film 414A Carbon-based / carbonaceous paste 415 Barrier membrane 420 Flexible Perovskite Solar Devices 440 Flexible PCB 442 Transparent Conductive Oxide (TCO) Coating 450 First Charge Transport Layer (CTL) 460 Photoactive Perovskite Layer 470 Upper CTL

Claims

1. A flexible release substrate including a release surface, A transferable electrode comprising at least one conductive layer placed on top of the release surface of a release substrate, wherein the at least one conductive layer comprises a solution-treated conductive layer, and A transferable electrode device including, The material includes at least one conductive layer, which comprises an interfacial conductive layer configured to interfacially connect with the receiving surface, and a carbonaceous conductive layer, The transferable electrode is detachably attached to the release surface of the release substrate. Transferable electrode device.

2. The transferable electrode apparatus according to claim 1, wherein at least one conductive layer comprises at least one further conductive layer selected from a metallic conductive layer; a carbonaceous conductive layer; an organic conductive layer; or a combination thereof.

3. The transferable electrode device according to claim 1 or 2, wherein at least one organic conductive layer comprises a charge transport layer, preferably a PEDOT-based conductive layer, and / or the carbonaceous conductive layer is formed from a carbon-based paste comprising a conductive carbonaceous filler, a binder material, and an organic solvent.

4. A transferable electrode apparatus according to any one of claims 1 to 3, wherein the transferable electrode further comprises at least one barrier film layer disposed between a release substrate and at least one conductive layer, and / or the at least one metallic conductive layer comprises an Ag, Al, Cu, or Au-based layer, and / or the release substrate comprises a flexible polymer, preferably a polymer film, more preferably polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polypropylene (PP), or ethylene tetrafluoroethylene (ETFE) film, paper film, or aluminum foil.

5. The release surface includes an anti-adhesion surface selected from the group consisting of a fluorinated polymer and a silicone polymer, preferably polytetrafluoroethylene (PTFE), or a silicone derivative such as siloxane, or The release surface may be activated to separate the transferable electrode from the release substrate, preferably containing a thermoactive adhesive polymer, which preferably includes a thermoplastic polymer selected from the group consisting of ethylene-vinyl acetate (EVA) copolymer, polyethylene, polyethylene oxide (PEO), and polystyrene (PS), or it may contain an activated adhesive, A low-bonding sacrificial layer is sandwiched between a flexible release substrate and a transferable electrode, and when the low-bonding sacrificial layer is activated in such a way that the flexible release substrate can be separated from the transferable electrode by breaking the low-bonding sacrificial layer, it inherently has low bonding strength or low bonding strength, and the low-bonding sacrificial layer Low-binding-strength organic nonpolymeric solid; or An activated adhesive that, when activated by heat or radiation, breaks down a low-bonding sacrificial layer, thereby separating the transferable electrode from the flexible release substrate. A transferable electrode device according to any one of claims 1 to 4, preferably comprising at least one of the above.

6. The transferable electrode apparatus according to any one of claims 1 to 5, wherein at least one conductive layer has a dry layer thickness of 1 μm to 100 μm, preferably 10 to 80 μm, more preferably 20 to 60 μm, and even more preferably about 40 μm.

7. A flexible substrate coated with a transparent conductive oxide coating, A first charge transport layer, such as a hole transport layer or an electron transport layer, is arranged on top of a flexible substrate. At least one photoactive layer is placed on top of the first charge transport layer, A transferable electrode device according to any one of claims 1 to 6, wherein a photoactive layer is placed on top of the photoactive layer, and an interfacial connecting conductive layer is placed on top of the photoactive layer. Optoelectronic devices including optoelectronic devices.

8. The optoelectronic device according to any one of claims 1 to 7, further comprising a second charge transport layer, such as a hole transport layer or an electron transport layer, which is arranged on a flexible substrate and positioned between at least one photoactive layer and a transferable electrode.

9. The optoelectronic device according to claim 7 or 8, wherein at least one of the first charge transport layer or the second charge transport layer is preferably selected from at least one of tin oxide, PEDOT, PEDOT:PSS, Spiro-OMeTAD, PPDT2FBT, or phenyl-C61-methyl butyrate (PCBM) / ethoxylated polyethyleneimine (PEIE).

10. The photoactive layer comprises at least one perovskite layer or at least one organic photovoltaic cell active layer, and / or the transparent conductive oxide (TCO) coating is selected from at least one of tin-doped indium oxide (ITO), fluoride-doped tin oxide (FTO), aluminum-doped zinc oxide (AZO), or indium-doped cadmium oxide, and / or The flexible substrate comprises a polymer, preferably a polymer film, preferably polyethylene terephthalate (PET), polyethylene naphthalate (PEN), or ethylene tetrafluoroethylene (ETFE) film, more preferably a polyethylene terephthalate (PET) film, and / or The optoelectronic device according to any one of claims 7 to 9, wherein the peel-off substrate is at least partially separated from covering the transferable electrode.

11. A process of preparing a flexible release substrate including a release surface, A step of applying at least one layer of a conductive medium to the peel surface of a peel substrate, wherein the conductive medium comprises a fluid mixture of a conductive composition and a solvent, and at least one layer of the conductive medium comprises an interfacial connection conductive composition configured to form an interfacial connection conductive layer and interfacially connect with the receiving surface, and the interfacial connection conductive composition comprises a fluid mixture of a carbonaceous conductive composition and a solvent, A step of heat-treating at least one layer of the conductive medium to remove the solvent from each layer of the conductive medium, This involves the process of forming a transferable electrode on the peel-off substrate. A method for forming a transferable electrode for a flexible electronic device, including, The transferable electrode is detachably attached to the release surface of the release substrate. method.

12. The method according to claim 11, wherein at least one layer of the conductive medium further comprises at least one further layer comprising a fluid mixture of at least one of a metallic composition, a carbonaceous conductive composition, or an organic conductive composition and a solvent.

13. The transferable electrode comprises at least two layers of a conductive medium, and the application process is as follows: A step of forming a first conductive layer by applying at least one layer of a metallic conductive medium containing a fluid mixture of a metallic composition and a solvent to a release substrate, A step of forming an interfacial conductive layer by applying at least one layer of an interfacial conductive composition to a first conductive layer, and The method according to claim 12, including the method described in claim 12.

14. The method according to any one of claims 11 to 13, wherein the heat treatment step includes heat treatment of the transferable electrode after each conductive medium layer has been applied to it.

15. The method according to claim 13, wherein at least one layer of a metallic conductive medium is heat-treated prior to the application of the interfacial conductive composition thereto, and / or the interfacial conductive composition is heat-treated after its application to the first conductive layer.

16. A step of forming at least one barrier film layer by applying at least one barrier film material composition between a release substrate and at least one layer of a conductive medium, wherein at least one layer of the conductive medium is printed on the at least one barrier film layer. The method according to any one of claims 11 to 15, further comprising:

17. At least one layer of the metallic conductive medium comprises a metallic paste, preferably an Ag, Cu, Al, or Au-containing paste, and / or At least one layer of the carbonaceous conductive composition is formed from a carbon-based paste comprising a conductive carbonaceous filler, a binder material, and an organic solvent, and / or The method according to any one of claims 12 to 16, wherein the release substrate comprises a flexible polymer, preferably a polymer film, more preferably polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polypropylene (PP), or ethylene tetrafluoroethylene (ETFE) film, paper film, or aluminum foil.

18. The method according to any one of claims 11 to 17, wherein the transferable electrode has a dry layer thickness of 1 μm to 100 μm, preferably 10 to 80 μm, more preferably 20 to 60 μm, and even more preferably about 40 μm.

19. The release surface may be activated to separate the transferable electrode from the release substrate, and may contain an activated adhesive such as a thermoplastic polymer selected from the group consisting of ethylene-vinyl acetate (EVA) copolymer, polyethylene, polyethylene oxide (PEO), and polystyrene (PS), or The release surface is a low-bonding sacrificial layer sandwiched between a flexible release substrate and a transferable electrode, and includes a low-bonding sacrificial layer that inherently has low bonding strength or low bonding strength when activated, such that the flexible release substrate can be separated from the transferable electrode by breaking the low-bonding sacrificial layer. The method according to any one of claims 11 to 18.

20. Each layer of the conductive medium The method according to any one of claims 11 to 19, applied to a release substrate using at least one of casting, doctor bladeding, blade coating, bar coating, screen printing, inkjet printing, pad printing, knife coating, meniscus coating, slot die coating, gravure printing, reverse gravure printing, kiss coating, microroll coating, curtain coating, slide coating, spray coating, flexographic printing, offset printing, rotary screen printing, or dip coating.

21. A process of pre-pressing the electrodes to improve the interparticle connectivity of the electrodes and the interlayer connectivity of the conductive medium. A process involving heat treatment at high temperatures for a long period of time, or At least one solvent exchange process The method according to any one of claims 11 to 20, further comprising a pretreatment step for the transferable electrode, selected from at least one of the following, prior to applying the transferable electrode to the surface of the electron carrier substrate.

22. A method for forming a flexible electronic device, A. A step of preparing a transferable electrode device according to any one of claims 1 to 6, or a transferable electrode formed according to the method described in any one of claims 11 to 21, B. A step of preparing an electron carrier substrate having a selected lower electron layer configured to accept transferable electrodes on its upper receiving surface, C. A step of applying a transferable electrode to the receiving surface of an electronic carrier substrate, D. A step of removing the release substrate from the transferable electrode. Includes, This allows the transferable electrode to produce an electronic device to which it is applied. method.

23. The transferable electrode is pressed and / or pressurized on the receiving surface of the electron carrier substrate and / or The electronic carrier substrate, A flexible substrate coated with a transparent conductive oxide coating, A first charge transport layer is placed on top of a flexible substrate, At least one photoactive layer is placed on top of the first charge transport layer and Includes, The receiving surface includes a photoactive layer, or The electronic carrier substrate, A flexible substrate coated with a transparent conductive oxide coating, A first charge transport layer is placed on top of a flexible substrate, A second charge transport layer is placed on top of at least one photoactive layer and Includes, The receiving surface includes a second charge transport layer. The method according to claim 22.

24. The method according to any one of claims 22 to 23, wherein at least one of the first charge transport layer or the second charge transport layer comprises at least one hole transport layer and at least one electron transport layer, or where at least one of the first charge transport layer or the second charge transport layer is preferably selected from at least one of tin oxide, PEDOT, PEDOT:PSS, Spiro-OMeTAD, PPDT2FBT, or phenyl-C61-methyl butyrate (PCBM) / ethoxylated polyethyleneimine (PEIE).

25. The photoactive layer comprises at least one perovskite layer or at least one organic photovoltaic cell active layer, and / or the transparent conductive oxide (TCO) coating is selected from at least one of tin-doped indium oxide (ITO), fluoride-doped tin oxide (FTO), aluminum-doped zinc oxide (AZO), or indium-doped cadmium oxide, and / or The method according to any one of claims 22 to 24, wherein the flexible substrate comprises a polymer, preferably a polymer film, preferably polyethylene terephthalate (PET), polyethylene naphthalate (PEN), or ethylene tetrafluoroethylene (ETFE) film, more preferably a polyethylene terephthalate (PET) film.

26. The electronic carrier substrate, Prepare a flexible substrate coated with a transparent conductive oxide coating, Applying a first charge transport layer that is placed on top of a flexible substrate, Applying at least one photoactive layer superimposed on the first charge transport layer, The method involves optionally applying a second charge transport layer that is superimposed on at least one photoactive layer. The method according to any one of claims 22 to 25, prepared by...

27. Each layer, The method according to claim 26, wherein at least one of casting, doctor bladeding, blade coating, bar coating, screen printing, inkjet printing, pad printing, knife coating, meniscus coating, slot die coating, gravure printing, reverse gravure printing, kiss coating, microroll coating, curtain coating, slide coating, spray coating, flexographic printing, offset printing, rotary screen printing, or dip coating is applied to a subsequent layer.

28. The method according to any one of claims 23 to 27, comprising a roll-to-roll printed electrode transfer method.

29. A photoelectronic device, such as at least one of a photovoltaic cell or a photoactive sensor, formed using the method according to any one of claims 22 to 28.

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