Non-equilibrium thermal curing processes

Abstract

To provide a method of flash-curing a respective layer in an electronic device stack.SOLUTION: A method includes providing a stack of layers including a substrate and one or more electronically-active layers disposed on a surface of the substrate. The method further includes applying, over the stack of layers, a thermally-curable layer of material. The method further includes performing a non-equilibrium thermal process that includes raising a temperature of the thermally-curable layer of material above a first temperature for a length of time sufficient to cure the thermally-curable layer of material while maintaining the stack of layers below a second temperature that is less than the first temperature. The stack of layers is robust to temperatures below the second temperature.SELECTED DRAWING: Figure 1A

Description

[Technical field]

[0001] Some embodiments of the present disclosure relate generally to non-equilibrium thermal curing processes ("flash cure"), and more specifically to flash curing materials in organic thin film devices. Some embodiments of the present disclosure relate to solution-based deposition of cathodes in organic light emitting diodes (OLEDs). [Background technology]

[0002] Thin film electronic devices, such as light emitting diodes, photovoltaic devices, and thin film transistors, typically comprise a stack of layers fabricated on a substrate, including one or more electronically active layers. The stack of layers is fabricated sequentially, with one layer fabricated on top of the layer below it (e.g., by coating, printing, or lithographic processes).

[0003] It is beneficial to make each layer as quickly and cheaply as possible. Although various solution-based and / or roll-to-roll processing techniques are generally very fast and cheap, not all electronic device layers are compatible with solution-based and / or roll-to-roll processing. For example, some layers have traditionally been deposited using evaporation (which is slow and expensive) and / or thermal treatments (e.g., curing processes) in furnaces (which are also slow and expensive). Summary of the Invention [Problem to be solved by the invention]

[0004] Embodiments of the present disclosure reduce the need for slow and expensive techniques such as vapor deposition and / or thermal curing in an oven by providing methods for fabricating certain electronic device layers in a manner that is compatible with solution-based and / or roll-to-roll processing techniques. [Means for solving the problem]

[0005] (A1) To that end, a method is provided for flash curing each layer in a stack of electronic devices. The method includes providing a stack of layers including a substrate and one or more electronically active layers disposed on a surface of the substrate. The method further includes applying a thermosetting layer of material over the stack of layers. The method further includes irradiating a surface of the stack of layers to initiate a non-equilibrium thermal process including raising the temperature of the thermosetting layer of material above a first temperature while maintaining the stack of layers below a second temperature that is lower than the first temperature, for a length of time sufficient to cure the thermosetting layer of material. The stack of layers is robust to temperatures below the second temperature.

[0006] In some embodiments of (A2)(A1), the stack of layers is a part of an organic light emitting diode (OLED) stack.

[0007] In some embodiments of (A3)(A1), the stack of layers is a stack for part organic photovoltaics.

[0008] (A4) In some embodiments of (A1)-(A3), the thermosetting layer of the material comprises a crosslinkable material. Performing a non-equilibrium thermal process includes crosslinking the crosslinkable material.

[0009] (A5) In some embodiments of (A1)-(A3), the thermosetting layer of material comprises a polymerizable material. Performing a non-equilibrium thermal process comprises polymerizing the polymerizable material.

[0010] In some embodiments of (A6)(A1)-(A3), the thermosetting layer of material is a heat-activatable doped layer comprising a semiconducting polymer host material and a dopant, and performing a non-equilibrium thermal process comprises heat-activating the heat-activatable doped layer.

[0011] In some embodiments of (A7)(A1)-(A6), the second temperature is the glass transition temperature of each layer in the stack of layers.

[0012] In some embodiments of (A8)(A1)-(A7), maintaining the stack of layers at the first temperature for a length of time sufficient to cure the thermosetting layer of material renders the stack of layers inoperable.

[0013] (A9) In some embodiments of (A1)-(A8), the second temperature is a bulk damage threshold temperature.

[0014] (A10) In some embodiments of (A1)-(A9), the second temperature is a temperature that causes cracking or warping of each layer in the stack of layers.

[0015] (A11) In some embodiments of (A1)-(A10), the length of time sufficient to cure the thermosetting layer of material at the first temperature is less than 10 seconds, less than 20 seconds, or less than 1 minute, or less than 10 minutes.

[0016] (A12) In some embodiments of (A1)-(A11), the length of time sufficient to cure the thermosetting layer of material at the second temperature is greater than 10 minutes, greater than 1 hour, greater than 2 hours, greater than 8 hours, greater than 12 hours, or greater than 24 hours.

[0017] (A13) In some embodiments of (A1)-(A12), the second temperature is a temperature that causes a first amount of thermal deformation in a first layer in the stack of layers, and the first amount of thermal deformation causes cracking or warping in a second layer in the stack of layers, different from the first layer.

[0018] (A14) In some embodiments of (A13), the first layer is a substrate.

[0019] (A15) In some embodiments of (A13) to (A14), the thermal deformation is plastic deformation.

[0020] (A16) In some embodiments of (A1)-(A15), the thermosetting layer of material is the electronically active layer of material in the stack of layers.

[0021] (A17) In some embodiments of (A1)-(A16), a thermoset material layer is produced from a thermosetting layer of material by a non-equilibrium thermal process. The method further includes packaging an electronic device including the thermoset material layer and an electrode disposed between the substrate and the thermoset material layer. The thermoset material layer is a respective layer in a stack of electronically active layers including the electrode.

[0022] (B1) Further provided is an electronic device. The electronic device includes a crosslinked material layer formed from a crosslinkable material. The electronic device further includes a layer of a second material. The crosslinked material layer is disposed on the layer of the second material. A threshold temperature for crosslinking the crosslinkable material is higher than a damage threshold temperature of the layer of the second material. The electronic device may be made according to (A1)-(A12) or may have any of the features described with respect to (A1)-(A12).

[0023] (C1) Further provided is an electronic device. The electronic device comprises a layer of thermally activated doped material comprising a semiconducting polymer host material and a dopant. The electronic device further comprises a layer of a second material. The layer of thermally activated doped material is disposed on the layer of the second material. A threshold temperature for thermally activating the dopant is higher than a damage threshold temperature of the layer of the second material. The electronic device may be fabricated according to (A1)-(A12) or may have any of the features described with respect to (A1)-(A12).

[0024] (D1) Further provided is an electronic device. The electronic device includes a polymeric material layer formed from a polymerizable material. The electronic device further includes a layer of a second material. The polymeric material layer is disposed on the layer of the second material. A threshold temperature for polymerizing the polymerizable material is higher than a damage threshold temperature of the layer of the second material. The electronic device may be made according to (A1)-(A12) or may have any of the features described with respect to (A1)-(A12).

[0025] (E1) There is further provided a method of depositing a cathode on an OLED stack. The method includes providing a substrate having at least a partial OLED stack disposed on a surface of the substrate. The method further includes depositing a solution including a metal compound suspended in an aliphatic solvent on the partial OLED stack. The method further includes forming a conductive solid layer from the metal compound in the solution to form a cathode for the partial OLED stack.

[0026] (E2) In some embodiments of (E1), the partial OLED stack includes, in order of proximity to the substrate, an anode, a hole injection layer, a hole transport layer, an emissive layer, an electron transport layer, and an electron injection layer.

[0027] (E3) In some embodiments of (E1)-(E2), the anode is a transparent conductive layer.

[0028] (E4) In some embodiments of (E1)-(E3), the partial OLED stack is part of a bottom-emitting OLED stack.

[0029] (E5) In some embodiments of (E1)-(E4), the metal compound comprises a silver (Ag) compound or an aluminum (Al) compound.

[0030] (E6) In some embodiments of (E1)-(E5), the cathode is reflective.

[0031] (E7) In some embodiments of (E1)-(E6), the cathode has a conductivity of 0.001 to 1.0 Ω / □ / mil.

[0032] (E8) In some embodiments of (E1)-(E7), the partial OLED stack is at least 1 cm above the substrate. 2 Covers a continuous area of.

[0033] (E9) In some embodiments of (E1)-(E8), the partial OLED stack includes an anode comprising a material other than indium tin oxide (ITO).

[0034] (E10) In some embodiments of (E1)-(E9), the partial OLED stack is comprised of a plurality of layers. The method further includes fabricating the partial OLED stack using a solution-based process to form each layer of the partial OLED stack, and depositing a transparent conductive layer using a solution-based process to form an anode for the partial OLED stack.

[0035] (E11) In some embodiments of (E1)-(E10), the solution containing the metal compound is deposited using a roll-to-roll process.

[0036] (E12) In some embodiments of (E1)-(E11), the metal compound comprises conductive particles functionalized to be soluble in an aliphatic solvent.

[0037] (E13) In some embodiments of (E1)-(E12), the partial OLED stack comprises a plurality of layers, each of which is insoluble in an aliphatic solvent.

[0038] (E14) In some embodiments of (E1)-(E13), the metal compound comprises conductive particles. Forming a conductive solid layer from the solution to form a cathode for the partial OLED stack comprises thermally curing the solution.

[0039] (F1) Further provided is a method of depositing a cathode on an OLED stack. The method includes providing a substrate having at least a partial organic light emitting diode (OLED) stack disposed on a surface of the substrate, depositing a solution comprising a metal and a reducing agent over the partial OLED stack, and reducing the metal to precipitate the metal from the solution. In some embodiments, the solution includes a metal compound comprising a metal, where the metal is not in a metallic state within the metal (e.g., the metal element has an oxidation state other than the oxidation state in which it is metallic).

[0040] (F2) In some embodiments of (F1), the partial OLED stack includes, in order of proximity to the substrate, an anode, a hole injection layer, a hole transport layer, an emissive layer, an electron transport layer, and an electron injection layer.

[0041] (F3) In some embodiments of (F2), the anode is a transparent conductive layer.

[0042] (F4) In some embodiments of (F1)-(F3), the partial OLED stack is part of a bottom-emitting OLED stack.

[0043] (F5) In some embodiments of (F1)-(F4), the metal comprises silver (Ag) or aluminum (Al).

[0044] (F6) In some embodiments of (F1)-(F5), the cathode is reflective.

[0045] (F7) In some embodiments of (F1)-(F6), the cathode has a conductivity of 0.001 to 1.0 Ω / □ / mil.

[0046] (F8) In some embodiments of (F1)-(F7), the partial OLED stack is at least 1 cm above the substrate. 2 Covers a continuous area of.

[0047] (F9) In some embodiments of (F1)-(F8), the partial OLED stack includes an anode that includes a material other than indium tin oxide (ITO).

[0048] (F10) In some embodiments of (F1)-(F9), the partial OLED stack is comprised of multiple layers. The method further includes fabricating the partial OLED stack using a solution-based process to form each layer of the partial OLED stack, and depositing a transparent conductive layer using a solution-based process to form an anode for the partial OLED stack.

[0049] (F11) In some embodiments of (F1)-(F10), the solution containing the metal and the reducing agent is deposited using a roll-to-roll process.

[0050] (F12) In some embodiments of (F1)-(F11), the partial OLED stack , the solution comprises a plurality of layers, the solution comprising a solvent, and each layer of the plurality of layers of the partial OLED stack is insoluble in the solvent.

[0051] (G1) There is further provided an electronic device. The device includes a substrate and a portion of an OLED stack disposed on a surface of the substrate. The partial OLED stack includes, in order of proximity to the substrate, an anode and one or more active layers. The electronic device further includes a cathode comprising a solid layer of sintered conductive particles. The electronic device may be fabricated according to (E1)-(E14) or (F1)-(F12) or may have any of the features described with respect to (E1)-(E14) or (F1)-(F12). [Brief description of the drawings]

[0052] [Figure 1A] FIG. 1 illustrates a roll-to-roll process setup for at least partially fabricating an electronic device according to some embodiments. [Figure 1B] 1 illustrates a roll-to-roll process setup for at least partially fabricating an electronic device according to some embodiments. [Figure 2A] 1 illustrates a non-equilibrium thermal curing process according to some embodiments. [Figure 2B] 1 illustrates a non-equilibrium thermal curing process according to some embodiments. [Figure 2C] 1 illustrates a non-equilibrium thermal curing process according to some embodiments. [Figure 3A] 1 illustrates a solution-based process for depositing a cathode onto a stack of layers according to some embodiments. [Figure 3B]1 illustrates a solution-based process for depositing a cathode onto a stack of layers according to some embodiments. [Figure 4] 1 is a flowchart of a method for thermally curing a layer in a stack of layers, according to some embodiments. [Figure 5A] 3 shows a flowchart of a method for solution-based deposition of a cathode over a portion of an OLED stack according to some embodiments. [Figure 5B] 3 shows a flowchart of a method for solution-based deposition of a cathode over a portion of an OLED stack according to some embodiments.

[0053] Like reference numbers refer to corresponding parts throughout the drawings. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0054] Reference will now be made in detail to the embodiments, examples of which are illustrated in the accompanying drawings. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the various embodiments described. However, it will be apparent to those skilled in the art that the various embodiments described may be practiced without these specific details. In other instances, well-known methods, procedures, components, circuits, and networks have not been described in detail so as not to unnecessarily obscure aspects of the embodiments.

[0055] 1A-1B are diagrams illustrating a roll-to-roll process setup for at least partially manufacturing an electronic device, according to some embodiments.

[0056] 1A shows a flexographic printing setup 100 for printing electronically active layers (and other layers) according to some embodiments. Although flexographic printing is used as an example of a roll-to-roll process, those skilled in the art with the benefit of this disclosure will understand that other roll-to-roll processes can also be applied to coat and print device materials. Such processes may include slot die coating, gravure coating, microgravure coating, roll coating, comma coating, bar coating, rod coating, knife coating, blade coating, slide coating, curtain coating, spray coating, rotary screen coating, etc., depending on the application. Printing, inkjet printing, etc.

[0057] The flexographic printing mechanism 100 includes a fountain roller 102. The fountain roller 102 transfers ink located in an ink pan 104 to an anilox roller 106. In modern flexographic printing, the anilox roller 106 is sometimes called a metering roller.

[0058] The anilox roller 106 is responsible for transferring ink to a flexible printing plate 108 attached to the plate cylinder 110. In some embodiments, the anilox roller 106 transfers a uniform thickness of ink to the flexible printing plate 108 attached to the plate cylinder 110 (e.g., the anilox roller 106 has finely engraved cells with specific ink volumes). In some embodiments, an optional doctor blade 114 scrapes the anilox roller 106 to ensure that only the ink contained within the engraved cells is delivered to the flexible printing plate 108.

[0059] In some embodiments, the flexible printing plate 108 is made from a soft, flexible, rubber-like material. In some embodiments, the flexible printing plate 108 is held to the plate cylinder 110 using a mounting adhesive tape 112. In other embodiments, the flexible printing plate 108 is held to the plate cylinder 110 using magnets, tension straps, and / or ratchets.

[0060] The flexographic printing mechanism 100 further includes an impression cylinder 116 (also called a "printing anvil") that applies pressure to the plate cylinder 110, thereby transferring the ink image on the flexible printing plate 108 to a printing substrate 118. In some embodiments, the ink is the solution from which each layer in the stack of layers is formed (e.g., any of the layers described with respect to subsequent figures). In some embodiments, the printing substrate 118 is used as the substrate in methods 400 (FIG. 4) and 500 (FIGS. 5A-5B), described below.

[0061] In some circumstances, it may be necessary to cure the ink printed on the print substrate 118, as shown in FIG. 1A. To that end, FIG. 1B illustrates a photonic curing mechanism 115, according to some embodiments. The photonic curing mechanism 115 includes a pair of transport rollers (e.g., transport roller 120a and transport roller 120b) that transport the print substrate 118. The print substrate 118 is then exposed to radiation from a lamp 122 to cure the ink on the print substrate 118 (e.g., by initiating a UV curing or thermal curing process). In some embodiments, as described with reference to FIGS. 2A-2C and method 400 (FIG. 4), the lamp 122 is a flash curing lamp (e.g., a xenon flash curing lamp) that deposits energy (e.g., in the form of photons) on the top surface of the print substrate 118. Once cured, the print substrate 118 is then transported through a pair of pull rollers (e.g., pull roller 124a and pull roller 124b). In some embodiments, additional (eg, subsequent) device layers can be printed on top of the cured ink by repeating the process shown in Figures 1A-1B.

[0062] 2A-2C illustrate a non-equilibrium thermal curing process (e.g., a flash curing process), according to some embodiments. In FIG. 2A, a stack of layers 202 is provided that includes a substrate 204 and one or more electronically active layers disposed on a surface of the substrate. For example, one or more of layers 206a, 206b, and 206c are electronically active layers. A thermosettable layer 208 of material is applied over the stack of layers 202. Light 210 from a flash curing lamp (e.g., lamp 122 of FIG. 1) is incident on the thermosettable layer 208 of material.

[0063] It should be noted that in some embodiments, the thermal cure process described herein is considered a non-equilibrium thermal process when the two layers of the stack are at substantially different temperatures for the period of time required to complete the cure process. In some embodiments, a curable layer is elevated above a first temperature and another layer is maintained below a second temperature that is lower than the first temperature, and the device is robust to the second temperature. Because the first and second temperatures are different, the process is considered a non-equilibrium thermal process.

[0064] To that end, as shown in FIG. 2B, in flash curing, energy is rapidly (less than the thermalization time) deposited only at the top surface (e.g., thermosetting layer of material 208) where substantially all of the light 210 is absorbed. This allows the top surface (e.g., thermosetting layer of material 208) to be heated to a high temperature (e.g., >500° C.), but as that energy is thermalized into the stack of layers 202 below (including the substrate), the temperature (T) of the top surface decreases and the temperature of the substrate increases. However, because the thermal capacity of the substrate is much greater than the thermal capacity of the surface, the temperature of the stack of layers 202 increases only slightly (e.g., less than the damage threshold of the stack of layers 202), thereby preventing thermal damage to other layers during the high temperature curing of the thermosetting layer of material 208.

[0065] FIG. 2C shows the resulting structure. More specifically, FIG. 2C shows an electronic device 212 including a thermoset layer 208 of material formed from a thermoset material (e.g., a crosslinked material formed from a crosslinkable material, a polymerized material formed from a polymerizable material, and / or a thermally activated doped material including a semiconducting polymer host material and a dopant). The electronic device further includes a second material layer (e.g., any of layers 206a, 206b, and / or 206c). The thermoset material layer 208 is disposed on top of the second material layer. The threshold temperature for thermally curing the material 208 is higher than the damage threshold temperature of the second material layer. It should be noted that the electronic device can include subsequent layers, such as additional electronically active layers and barrier layers (not shown, but similar to barrier layer 314 of FIG. 3B) to protect the electronic device (i.e., the thermoset layer does not have to be the top layer of the electronic device).

[0066] 3A-3B illustrate a solution-based process for depositing a cathode over a stack of layers according to some embodiments. In particular, FIGS. 3A-3B illustrate an example of a solution-based process for depositing a cathode for a bottom-emitting OLED. In FIG. 3A, a substrate 304 is provided having at least a partial OLED stack 302 disposed on a surface of the substrate 304. For example, the partial OLED stack 302 includes one or more of an anode 306a, a hole injection layer 306b, a hole transport layer 306c, an emissive layer 306d, an electron transport layer 306e, and an electron injection layer 306f. In some embodiments, the partial OLED stack includes more than one of the aforementioned layers and does not include at least one of the aforementioned layers. For example, in some embodiments, the partial OLED stack does not include a hole transport layer and / or an electron transport layer. In some embodiments, each layer in the partial OLED stack is solution processed (e.g., processed using a roll-to-roll process). In some embodiments, four or more layers in the stack are solution processed. It should be noted that as more layers are solution processed, it becomes increasingly difficult to find orthogonal chemistries such that application of a layer does not damage previously deposited layers. Some embodiments described herein provide methods for depositing solution-processed silver or aluminum cathodes using chemistries (e.g., aliphatic solvents or Tollens reactions) that do not damage the three or more solution-processed layers already deposited in the stack. In some embodiments, one or more solution-processed (or solution-processable) layers are susceptible to dissolution in any of the classes of solvents including alcohols, esters, aldehydes, ethers, ketones, aromatics, and polar protic solvents.

[0067] For example, in some embodiments, an exemplary partial OLED stack is fabricated using the following corresponding solvents (placed in parentheses): anode (water), hole injection layer (alcohol-based solvent), emissive layer (aromatic solvent), electron accepting layer (ether solvent).

[0068] A solution containing a metal compound (e.g., a silver (Ag) compound or an aluminum (Al) compound) 308 is deposited on the partial OLED stack. In some embodiments, the solution further comprises a solvent, and none of the layers in the partial OLED stack are soluble in the solvent (e.g., either because the layers are crosslinked or because the layers are inherently insoluble in the particular solvent). The cathode 310 for the partial OLED stack is formed from a metal compound. For example, in some embodiments, the metal compound comprises metal particles (e.g., nanoparticles), and the cathode is formed by thermally curing the solution to sinter the metal particles together. Alternatively, the cathode is formed using a Tollens reaction to reduce the metal in the metal compound to the metallic state. As used herein, the term compound is intended to encompass any material that includes the above metals in any oxidation state (e.g., nanoparticles in which the metal is in the metallic state, dissolved metal salts in which the metal is not in the metallic state).

[0069] FIG. 3B shows the resulting structure. More specifically, FIG. 3B shows a bottom-emitting OLED 312. The bottom-emitting OLED 312 includes a substrate 304 and a partial OLED stack 302 disposed on the surface of the substrate 304. For example, the partial OLED stack includes, in order of proximity to the substrate, an anode 306a and one or more active layers. For example, the one or more active layers include one or more of a hole injection layer 306b, a hole transport layer 306c, an emissive layer 306d, an electron transport layer 306e, and an electron injection layer 306f. The bottom-emitting OLED 312 further includes a cathode 310. In some embodiments, the cathode 310 includes a solid layer of sintered conductive particles (e.g., a porous metal layer). In some embodiments, the cathode 310 includes a crystalline layer of a metal that exhibits a Tollens response and has a characteristic grain size.

[0070] In some embodiments, additional layers can be applied to the bottom-emitting OLED 312. For example, the bottom-emitting OLED 312 shown in Figure 3B includes a barrier layer 314 and a laminate 316 to protect the bottom-emitting OLED 312 from physical damage, such as water damage.

[0071] Note that in some embodiments, the stack shown in Figures 3A-3B is inverted so that the anode is on top (e.g., the OLED is a top-emitting OLED). In some embodiments, the anode is a deposited silver anode according to embodiments described herein.

[0072] 4 shows a flow chart of a method 400 for thermally curing a layer in a stack of layers, according to some embodiments. Various steps described with reference to method 400 may optionally be combined with other methods and processes described herein, such as method 500 described below with reference to FIGS. 5A-5C.

[0073] Various electronic devices, such as OLEDs, are manufactured by fabricating a stack of layers on a substrate (e.g., via lithography, coating, and / or printing processes, one after the other). During the fabrication of such electronic devices, it is often necessary to perform a thermal process on one of the layers, e.g., to polymerize, crosslink, or dope the layer. Thus, when a thermal process is performed by increasing the bulk temperature of the stack (e.g., by placing the stack in a furnace), the other layers in the stack must be robust to the thermal treatment (e.g., the other layers cannot be irreversibly damaged by the thermal treatment such that the electronic device does not function or has an unacceptable lifetime). For example, such damage can occur to a particular layer when the temperature of that layer is increased above its damage threshold (e.g., the temperature at which the layer decomposes). Such damage can also be due to thermal expansion differences between various layers that cause mechanical failure. For example, multiple thin films (e.g., about 50 nm thick) may be stacked on a thick (e.g., 50 micron thick) substrate. If the substrate is heated significantly, it expands and the stack is carried away by the substrate, destroying the electronically active layers and / or barriers. This causes cracks in the rear layer.

[0074] One solution is to use thermally robust layers in the stack, but such thermally robust layers are expensive. Another solution is to carry out the thermal process at lower temperatures, but doing so may slow the thermal process to a level where it is no longer viable at production scale.

[0075] In some embodiments of the present disclosure, a non-equilibrium thermal process (e.g., a flash curing process) is used to overcome the above-mentioned problems. In a flash curing process, a flash curing lamp (e.g., a xenon flash curing lamp) is used to irradiate a material layer (e.g., a crosslinkable material layer, a polymerizable material layer, or a doped material layer) at its surface. The energy from the flash curing lamp is rapidly (e.g., less than the thermalization time) and deposited only in the top layer of the surface (e.g., the energy is deposited in the layer where the light is substantially absorbed). This allows the top layer of the surface to be heated to a high temperature (e.g., >500° C.), but the temperature of the underlying layers increases only slightly as the energy is thermalized to the underlying layers. Thus, the non-equilibrium thermal process of the present disclosure allows the flash cured layer to reach the temperature required to perform the thermal process without damaging the underlying layers. Using these flash curing processes, devices with less thermally stable substructures can be manufactured without increasing processing time, reducing product costs by almost an order of magnitude.

[0076] For example, such embodiments can be used to crosslink, polymerize, or activate dopants in a layer in an OLED stack without damaging the underlying layers. However, those skilled in the art, armed with the aid of this disclosure, will understand that the embodiments described herein can be used to fabricate other thin film devices (e.g., organic thin film devices) in which the thermal processing of a layer is rate-limited by the thermal sensitivity of one or more underlying layers. Such devices include, but are not limited to, thin film solar cell devices (e.g., organic photovoltaics), thin film transistors deposited on plastic substrates, and other devices fabricated on low-cost flexible substrates, such as touch sensors, non-OLED types of transparent displays, etc.

[0077] To that end, method 400 includes providing 402 a layer stack including a substrate and one or more electronically active layers disposed on a surface of the substrate. In some embodiments, the substrate is an organic substrate (e.g., a plastic such as polyethylene terephthalate (PET)). In some embodiments, the substrate is flexible. In some embodiments, the substrate is suitable for roll-to-roll processing. In some embodiments, providing the substrate includes providing the substrate as a roll (e.g., as a reel) to a roll-to-roll processing apparatus.

[0078] In some embodiments, the stack of layers is a partial OLED stack 404. In some embodiments, the stack of layers is a partial stack for an organic photovoltaic 406. However, one skilled in the art will appreciate that the method 400 is applicable to a variety of devices (e.g., thin film devices) deposited on a plastic substrate, such as thin film transistors, touch sensors, and types of transparent displays other than OLEDs.

[0079] The method 400 further includes applying 408 a thermosetting layer of material over the stack of layers. In some embodiments, applying the thermosetting layer of material includes slot die coating, gravure coating, microgravure coating, roll coating, comma coating, bar coating, rod coating, knife coating, blade coating, slide coating, curtain coating, spray coating, rotary screen printing, inkjet printing, and the like.

[0080] In some embodiments, the thermosetting layer of material comprises an organic material. In some embodiments, the thermosetting layer of material comprises a crosslinkable material (410). In some embodiments, the thermosetting layer of material comprises a polymerizable material (412). In some embodiments, the thermosetting layer of material is a thermally activatable doped layer that comprises a semiconducting polymer host material and a dopant (414).

[0081] The method 400 further includes performing 416 a non-equilibrium thermal process including increasing the temperature of the thermosetting layer of material (e.g., at least a portion of the thermosetting layer of material) above the first temperature for a length of time sufficient to cure the thermosetting layer of material (e.g., at least a portion of the thermosetting layer of material sufficient to electronically function in the electronic device) while maintaining the stack of layers below a second temperature that is less than the first temperature (e.g., no portion of the stack of device layers is above the second temperature and / or no respective portion of the stack of layers is above a damage threshold temperature of the respective portion). The stack of layers is robust to temperatures below the second temperature. In some embodiments, the stack of layers is not robust to temperatures above the second temperature (at least for a length of time sufficient to cure the thermosetting layer of material). In some embodiments, a second layer in the stack of layers is not robust to temperatures above the second temperature (at least for a length of time sufficient to cure the thermosetting layer of material). In some embodiments, the thermosetting layer of material is in direct contact with the second layer. In some embodiments, there are one or more intervening layers between the thermosetting layer and the second layer. In some embodiments, the thermosetting layer is deposited after the second layer. In some embodiments, the second layer is substantially transparent to light (e.g., visible light).

[0082] In some embodiments, performing the non-equilibrium thermal process comprises illuminating a surface of the stack of device layers to initiate the non-equilibrium thermal process. In some embodiments, performing the non-equilibrium thermal process comprises illuminating a surface of a thermosetting layer of material to initiate the non-equilibrium thermal process. In some embodiments, the surface is illuminated with a lamp.

[0083] In some embodiments, a stack of layers is considered robust (for a respective amount of time) for a respective temperature if the deliverable (e.g., a packaged device) has a predetermined lifetime and a predetermined yield. For example, in some embodiments, the predetermined yield is 90% and the predetermined lifetime is one year (e.g., under expected operating conditions). In some embodiments, the predetermined yield is 90% and the predetermined lifetime is two weeks.

[0084] In some embodiments, performing the non-equilibrium thermal process includes irradiating a surface of the thermosetting layer of the material using a flash lamp (e.g., a xenon flash lamp to photocure or "flash cure" the thermosetting layer of the material). In some embodiments, performing the non-equilibrium thermal process includes crosslinking the crosslinkable material (e.g., the first temperature is a crosslinking threshold temperature at which a sufficient amount of crosslinking occurs (e.g., 90% of the possible crosslinks) (418). In some embodiments, the crosslinkable material is soluble before crosslinking and insoluble after crosslinking (e.g., whatever solvent is used in the manufacturing process). In some embodiments, the method includes applying an additional layer over the thermosetting material layer after performing the non-equilibrium thermal process, the additional layer including a solvent. The thermosetting layer of the material is soluble in the solvent before performing the non-equilibrium thermal treatment and insoluble after performing the non-equilibrium thermal process.

[0085] In some embodiments, the first temperature is greater than 190° C., 200° C., 300° C., 400° C., or 500° C. In some embodiments, the second temperature is less than 100° C., 150° C., or 200° C.

[0086] In some embodiments, performing the non-equilibrium thermal process includes polymerizing (420) the polymerizable material (e.g., the first temperature is a polymerization threshold temperature at which a sufficient amount of polymerization occurs (e.g., 90% of possible polymerization).

[0087] In some embodiments, performing the non-equilibrium thermal process includes thermally activating (422) the thermally activatable doped layer (e.g., the first temperature is a dopant activation threshold temperature, e.g., performing the non-equilibrium thermal process increases the charge carrier density of the material).

[0088] In some embodiments, the first temperature is 500° C. or higher. In some embodiments, the second temperature is a damage threshold temperature of the stack of layers that is lower than the first temperature. For example, in some embodiments, the damage threshold temperature is about 150° C. It should be noted that there are an infinite number of ways in which the stack of layers can be irreversibly damaged if the temperature is too high, and thus an infinite number of corresponding damage threshold temperatures. For example, in some embodiments, the second temperature is the glass transition temperature of each layer in the stack of layers (e.g., each layer will melt easily if exposed to a temperature higher than its glass transition temperature). In some embodiments, the second temperature is a bulk damage threshold temperature (e.g., if the stack of layers is maintained at the first temperature for a sufficient length of time to cure the thermosetting layer of the material, the stack of layers will become inoperable). Stated another way, the bulk damage threshold temperature is the temperature at which the stack of layers will be irreversibly damaged if placed in an oven at that temperature for a sufficient length of time to cure the thermosetting layer of the material.

[0089] In some embodiments, the second temperature is a temperature that causes cracking or warping of each layer in the stack of layers. For example, at the second temperature, thermal expansion (deformation) of the substrate can cause the substrate to crack or warp, which can cause one or more of the electronically active layers to crack or warp, rendering the device inoperable. Alternatively, melting and resolidifying one layer in the stack of layers can cause a different layer in the stack of layers to crack or warp.

[0090] In some embodiments, the second temperature is a temperature that causes a first amount of thermal deformation in a first layer in the stack of layers. The first amount of thermal deformation causes a second layer in the stack of layers that is different from the first layer to crack or warp. In some embodiments, the first layer is a substrate. In some embodiments, the thermal deformation is plastic deformation. For example, raising the substrate to the second temperature for a significant period of time may cause the substrate to plastically deform (e.g., stretch) and cause small cracks in one or more layers (e.g., barrier layers) disposed on top of the substrate. Small cracks may limit the lifetime of the device below an acceptable threshold, for example, by allowing moisture into the device.

[0091] In some embodiments, the thermosetting layer of material is an electronically active layer of material in a stack of layers. In some embodiments, a thermosetting material layer is generated from the thermosetting layer of material by a non-equilibrium thermal process, and the method further includes packaging an electronic device including the thermosetting layer of material and an electrode disposed between the substrate and the thermosetting layer of material, where the thermosetting layer of material is each layer in the stack of electronically active layers including the electrode. For example, in some embodiments, there is no thermal protection layer between the thermosetting layer of material and other layers in the stack of layers that would be damaged if raised to a first temperature. One reason that the stack of layers does not include a thermal protection layer is that it is often difficult or impossible to form a thermal protection layer in a stack of electronic devices (e.g., OLED) stacks that maintains the electrical properties necessary for the function of the electronic device.

[0092] It should be noted that in some embodiments, the stack of layers is robust to the first temperature, and the flash cure process described herein is used to speed up the cure process.

[0093] It should be noted that in some embodiments, the crosslinking (or polymerization or dopant activation) threshold temperature is well below the first temperature and may in fact be below the damage threshold temperature (e.g., the second temperature). If the crosslinking (or polymerization or dopant activation) threshold temperature is below the damage threshold temperature, the crosslinking (or polymerization or dopant activation) can be performed at a temperature below the damage threshold temperature, but the length of time sufficient to cure the thermosetting layer of the material at the second temperature is more than 10 minutes, more than 1 hour, more than 2 hours, more than 8 hours, more than 12 hours, or more than 24 hours (e.g., too long for a roll-to-roll process). In contrast, in some embodiments, the length of time sufficient to cure the thermosetting layer of the material at the first temperature is less than 10 seconds, less than 20 seconds, less than 1 minute, or less than 10 minutes.

[0094] 5A-5B show a flowchart of a method 500 for solution-based deposition of a cathode on an OLED stack, according to some embodiments. Various steps described with reference to method 500 can optionally be combined with other methods and processes described herein, such as method 400 described above with reference to FIG.

[0095] When making solution-processed devices, it is essential that the solvent in a given layer does not dissolve the layers below it. This is accomplished by using a solvent that is orthogonal to the solvent of the underlying layer, or by rendering one or more layers insoluble by crosslinking. Ideally, all of these materials would be crosslinkable so that the choice of solvent would not be an issue. However, because these are electronically active materials and the ability to crosslink requires chemistry with additional functionality, the majority of the layers are made from materials that cannot be made crosslinkable or otherwise insoluble.

[0096] The cathode is the most difficult to design because it is the final layer in a bottom-emitting OLED stack and must not dissolve any of the layers below it (usually consisting of 3-5 layers). For this reason, in traditional solution-processed bottom-emitting OLED stacks, the cathode is not solution-processed; that is, while most OLED cathodes are metal films, most solution-processable metals contain nanoparticles suspended in a solvent. To stabilize the metal particles (which have mobile electrons), a polar solvent must usually be used. This creates problems because there are layers in a typical OLED stack that are soluble in polar solvents.

[0097] Rather, in a typical OLED fabrication process, the cathode is deposited by a vacuum deposition process (e.g., physical vapor deposition). However, vacuum deposition processes are significantly slower and more expensive than solution-based processes that can be performed using roll-to-roll processes as described above.

[0098] Method 500 reduces or mitigates these problems by using solvents (e.g., aliphatic solvents) in which the material stack is unaffected. With appropriate surface functionalization of the nanoparticles (by attaching ligands to their surface that alter the electronic properties of the surface), the nanoparticles can be suspended in such non-polar aliphatic solvents (e.g., C14-C16 variants or shorter).

[0099] To that end, the method 500 includes providing 502 a substrate having at least a partial OLED stack disposed on a surface of the substrate. In some embodiments, the partial OLED stack is comprised of multiple layers. In some embodiments, the substrate is an organic substrate (e.g., a polyimide substrate). In some embodiments, the substrate is a plastic such as ethylene terephthalate (PET). In some embodiments, the substrate is flexible. In some embodiments, the substrate is suitable for roll-to-roll processing. In some embodiments, providing the substrate includes providing the substrate as a roll (e.g., as a reel) to a roll-to-roll processing apparatus.

[0100] In some embodiments, method 500 further includes fabricating a partial OLED stack using solution-based processing to form each layer of the partial OLED stack, and depositing a transparent conductive layer to form an anode for the partial OLED stack using solution-based processing. In some embodiments, method 500 includes fabricating a partial OLED stack using solution-based processing to form one or more (e.g., less than all) layers and / or to form a majority of the layers (e.g., using a roll-to-roll process described herein).

[0101] It should be noted that in some circumstances (e.g., similar to the description of method 400 above), the substrate may be considered part of the OLED stack. Thus, a "partial OLED stack" refers to a second portion of the OLED stack that is distinct from the substrate.

[0102] In some embodiments, the OLED stack includes an anode that includes a material other than indium tin oxide (ITO) (e.g., the anode does not include ITO) (504). In some embodiments, the anode includes a conductive material in an organic matrix. In some embodiments, the anode includes silver nanowires in an organic matrix (e.g., a plastic matrix). In some embodiments, the organic matrix is ​​a cured epoxy. In some embodiments, in addition to the anode, the OLED stack includes one or more electronically active layers.

[0103] In some embodiments, the partial OLED stack is part of a bottom-emitting OLED stack (506) (e.g., the OLED stack emits light through the substrate, so that the substrate functionally serves as a superstrate). In some embodiments, the partial OLED stack includes, in order of proximity to the substrate, one or more, or multiple, or three or more of an anode, a hole injection layer, a hole transport layer, an emissive layer, an electron transport layer, and / or an electron injection layer (508). In some embodiments, one or more of these layers are omitted and / or the functions of two or more of these layers are combined or integrated into one layer. For example, in some embodiments, the partial OLED stack includes only an anode and an emissive layer, onto which a cathode is fabricated. In some embodiments, the anode is a transparent conductive layer (e.g., a transparent conductive film) (510).

[0104] In some embodiments, the partial OLED stack is at least 1 cm above the substrate. 2 (or 4cm 2 or 10cm 2 ) (512). Stated another way, method 500 produces large area OLEDs. Large area OLEDs require high electrical conductivity in their electrodes or the device will experience a significant voltage drop from one side of the electrode (e.g., anode or cathode) to the other. As a result, in use, one side of the OLED will emit more light than the other. To avoid this problem, in some embodiments, method 500 is used to make a cathode with a conductivity of 0.001 to 1.0 Ω / □ / mil. In some embodiments, the conductivity is greater than 0.001 Ω / □ / mil.

[0105] The method 500 includes depositing (514) a solution including a metal compound over the partial OLED stack. In some embodiments, the metal compound includes a silver (Ag) compound or an aluminum (Al) compound. In some embodiments, the metal compound is in the form of conductive particles. In some embodiments, the conductive particles are conductive metal particles (e.g., Ag or Al particles in a metallic state of zero oxidation. In some embodiments, the conductive particles are conductive nanoparticles (e.g., particles having an average diameter of less than 1 micron).

[0106] In some embodiments, the solution including the metal compound is deposited using a roll-to-roll process, for example, the solution includes an ink for roll-to-roll processing techniques.

[0107] In some embodiments, the solution includes a non-polar solvent (516). In some embodiments, the solution includes an aliphatic solvent (e.g., the aliphatic solvent includes C14-C16 molecules) (518). In some embodiments, the metal compound includes conductive particles functionalized to be soluble in the non-polar solvent (520). For example, in the case of an aliphatic solvent, the conductive particles can be functionalized to include the same carbon chains that make up the solvent (e.g., C14-C16 chains).

[0108] In some embodiments, each layer of the multiple layers of the partial OLED stack is insoluble in non-polar solvents (e.g., the layer is either crosslinked or the layer is not soluble in non-polar solvents at all). In some embodiments, a flash cure is used to crosslink layers that would otherwise be soluble in non-polar solvents, as described with reference to method 400 (FIG. 4).

[0109] The method 500 includes forming a conductive solid layer from a metal compound in solution to form a cathode for the partial OLED stack (522). In some embodiments, forming the cathode completes the electronically functional OLED (although additional layers, such as barrier layers or laminates, may be added for protection).

[0110] In some embodiments, the metal compound includes conductive particles (524). Forming a conductive solid layer from the solution to form a cathode for the partial OLED stack includes thermally curing (e.g., sintering) the solution. Thus, in such embodiments, the resulting cathode includes a plurality of sintered conductive particles (e.g., the resulting cathode is a porous metal layer). Note that depending on the extent of sintering, the conductive particles may not be individually discernible after thermal curing.

[0111] In some embodiments, the cathode is deposited from solution using a Tollens reaction. To that end, the solution includes a reducing agent (e.g., a reducing sugar) (526). Forming a conductive solid layer from solution to form a cathode for a partial OLED stack includes reducing a metal (e.g., Al or Ag) in a metal compound to precipitate the metal from solution. In some embodiments, in solution, the metal is a non-neutral metal (e.g., a non-zero oxidation state) and thus is not in metallic form. Rather, in solution, the metal is part of a larger molecule, such as a salt (although it may be dissolved).

[0112] In some embodiments, the cathode is reflective (528).

[0113] As used herein, it should be noted that when a first layer is described as being "on" a second layer, this does not mean that the first layer is in direct contact with the second layer unless expressly stated. Rather, the first layer is said to be on the second layer when the first layer is distal to the substrate (e.g., in terms of deposition) from the second layer. Stated differently, the first layer is said to be on the second layer when the first layer is deposited after the second layer. One or more intervening layers may be disposed between the second layer and the first layer on top of the second layer.

[0114] Additionally, as used herein, the term "substrate" is used to refer to an underlying object or layer upon which additional device layers are fabricated, although it is understood that such a layer may function as a substrate for fabrication purposes, but as a superstrate in terms of device functionality.

[0115] The foregoing description has been described with reference to specific embodiments for purposes of explanation. However, the above illustrative description is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations are possible in light of the above teachings. The present embodiments have been chosen and described in order to best explain the principles of the invention and its practical application, thereby enabling others skilled in the art to best utilize the invention and various embodiments with various modifications suited to the particular applications contemplated.

[0116] In this specification, terms such as "first," "second," and the like may be used to describe various elements, but it will be understood that these elements should not be limited by these terms. These terms are used only to distinguish one element from another. For example, a first example of a material layer can be called a second example of a material layer, and similarly, a second first example of a material layer can be called a first example of a material layer, without changing the meaning of the description, so long as all occurrences of a "first example of a material layer" are consistently renamed and all occurrences of a "second example of a material layer" are consistently renamed. Although a first example of a material layer and a second fist example of a material layer are both examples of a material layer, they are not the same example of a material layer.

[0117] The terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the claims. When used in the description of the embodiments and the appended claims, the singular forms "a", "an" and "the" are intended to include the plural forms unless the context clearly indicates otherwise. It will also be understood that the term "and / or" as used herein refers to and includes any and all possible combinations of one or more of the associated listed items. It will be further understood that the terms "comprises" and / or "comprising", as used herein, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0118] As used herein, the term "if" may mean "when" or "upon" or "in response to" that the stated precondition is true, depending on the context. Similarly, the phrases "[if the preconditions of a stated condition are determined to be true]" or "[if the preconditions of a stated condition are true]" or "[if the preconditions of a stated condition are true]" may be interpreted to mean "when" or "in response to determining" or "in response to determining" or "when" or "in response to detecting" the stated precondition is true, depending on the context.

Claims

1. providing a stack of layers comprising a substrate and one or more electronically active layers disposed on a surface of the substrate; applying a thermosetting layer of material onto the stack of layers; and irradiating a surface of the stack of layers to initiate a non-equilibrium thermal process that includes raising a temperature of the thermosetting layer of material above a first temperature for a length of time sufficient to cure the thermosetting layer of material, while maintaining the stack of layers below a second temperature that is lower than the first temperature; Including, The method, wherein the stack of layers is robust to temperatures below the second temperature.

2. The method of claim 1 , wherein the stack of layers is a partial organic light emitting diode (OLED) stack.

3. The method of claim 1 , wherein the stack of layers is a partial stack for an organic photovoltaic.

4. the thermosetting layer of material comprises a crosslinkable material; The method of claim 1 , wherein performing the non-equilibrium thermal process comprises crosslinking the crosslinkable material.

5. the thermosetting layer of material comprises a polymerizable material; The method of claim 1 , wherein performing the non-equilibrium thermal process comprises polymerizing the polymerizable material.

6. the thermosetting layer of material is a heat activatable doped layer comprising a semiconducting polymer host material and a dopant; The method of claim 1 , wherein performing the non-equilibrium thermal process comprises thermally activating the thermally activatable doped layer.

7. The method of claim 1 , wherein the second temperature is the glass transition temperature of each layer in the stack of layers.

8. The method of claim 1 , wherein the stack of layers is rendered inoperable by maintaining the stack of layers at the first temperature for a length of time sufficient to cure the thermosetting layer of material.

9. The method of claim 1 , wherein the second temperature is a bulk damage threshold temperature.

10. The method of claim 1 , wherein the second temperature is a temperature that causes each layer in the stack of layers to crack or warp.

11. 10. The method of claim 1, wherein the length of time sufficient to cure the thermosetting layer of material at the first temperature is less than 10 seconds, less than 20 seconds, or less than 1 minute, or less than 10 minutes.

12. 12. The method of claim 11, wherein the length of time sufficient to cure the thermosetting layer of material at the second temperature is greater than 10 minutes, greater than 1 hour, greater than 2 hours, greater than 8 hours, greater than 12 hours, or greater than 24 hours.

13. the second temperature is a temperature that causes a first amount of thermal deformation in a first layer in the stack of layers; The method of claim 1 , wherein the first amount of thermal deformation causes a second layer in the stack of layers, different from the first layer, to crack or warp.

14. The method of claim 13 , wherein the first layer is the substrate.

15. The method of claim 13, wherein the thermal deformation is plastic deformation.

16. The method of claim 1 , wherein the thermoset layer of material is an electronically active layer of material in the stack of layers.

17. a layer of thermoset material is produced from the thermoset layer of material by the non-equilibrium thermal process; The method comprises: packaging an electronic device comprising the thermosetting material layer and an electrode disposed between the substrate and the thermosetting material layer; The method of claim 1 , wherein the thermoset material layer is a respective layer in a stack of electronically active layers that includes the electrodes.

18. a cross-linked material layer formed from a cross-linkable material; a second layer of material; and Including, the cross-linked material layer is disposed on the second material layer; The electronic device, wherein a threshold temperature for crosslinking the crosslinkable material is greater than a damage threshold temperature of the second material layer.

19. The electronic device of claim 18 , wherein the damage threshold temperature is a glass transition temperature.

20. 20. The electronic device of claim 18, wherein the damage threshold temperature is a temperature that renders the second material layer irreversibly inoperable within the electronic device.

21. 20. The electronic device of claim 18, wherein the damage threshold temperature is a temperature that causes the second material layer to crack or warp.

22. The electronic device of claim 18 , wherein the damage threshold temperature is a bulk damage threshold temperature.

23. the damage threshold temperature is a temperature that causes a first amount of thermal deformation in a first layer, distinct from the second layer of material, within the electronic device; 20. The electronic device of claim 18, wherein the first amount of thermal deformation causes the second material layer to crack or warp.

24. 24. The electronic device of claim 23, wherein the first layer is a substrate.

25. The electronic device of claim 23 , wherein the thermal deformation is plastic deformation.

26. 20. The electronic device of claim 18, wherein the cross-linked material layer is an electronically active material layer within the electronic device.

27. 20. The electrode of claim 18, further comprising an electrode disposed between a substrate and the bridging material layer, the bridging material layer being a respective layer in a stack of electronically active layers that includes the electrode. Child devices.

28. a thermally activated doped material layer comprising a semiconducting polymer host material and a dopant; a second layer of material; and Including, the thermally activated doped material layer is disposed over the second material layer; An electronic device, wherein a threshold temperature for thermally activating the dopant is greater than a damage threshold temperature of the second material layer.

29. 30. The electronic device of claim 28, wherein the damage threshold temperature is a temperature that renders the second material layer irreversibly inoperable within the electronic device.

30. the damage threshold temperature is a temperature that causes a first amount of thermal deformation in a first layer, distinct from the second layer of material, within the electronic device; 30. The electronic device of claim 28, wherein the first amount of thermal deformation causes the second layer of material to crack or warp.

31. The electronic device of claim 30 , wherein the first layer is a substrate.

32. The electronic device of claim 30 , wherein the thermal deformation is plastic deformation.

33. 30. The electronic device of claim 28, wherein the thermally activated doped material layer is an electronically active material layer within the electronic device.

34. 30. The electronic device of claim 28, further comprising an electrode disposed between a substrate and the thermally activated doped material layer, the thermally activated doped material layer being a respective layer in a stack of electronically active layers that includes the electrode.

35. a polymeric material layer formed from a polymerizable material; a second layer of material; and Including, the polymeric material layer is disposed over the second material layer; The electronic device, wherein a threshold temperature for polymerizing the polymerizable material is greater than a damage threshold temperature of the second material layer.

36. the damage threshold temperature being a temperature that causes a first amount of thermal deformation in a first layer within the electronic device; 36. The electronic device of claim 35, wherein the first amount of thermal deformation causes a crack or warp in a second layer within the electronic device that is different from the first layer.

37. 37. The electronic device of claim 36, wherein the first layer is a substrate.

38. 37. The electronic device of claim 36, wherein the thermal deformation is plastic deformation.

39. 36. The electronic device of claim 35, wherein the layer of polymeric material is an electronically active layer of material in the electronic device.

40. 36. The electronic device of claim 35, further comprising an electrode disposed between a substrate and the layer of polymeric material, the layer of polymeric material being a respective layer in a stack of electronically active layers that includes the electrode.

41. providing a substrate having an at least partial organic light emitting diode (OLED) stack disposed on a surface of the substrate; depositing a solution comprising a metal compound suspended in an aliphatic solvent onto the partial OLED stack; and forming a conductive solid layer from the metal compound in the solution to form a cathode for the partial OLED stack; The method includes:

42. The partial OLED stacks, in order of proximity to the substrate, are An anode; A hole injection layer; A hole transport layer; A light-emitting layer; an electron transport layer; An electron injection layer; 42. The method of claim 41 , comprising:

43. 43. The method of claim 42, wherein the anode is a transparent conductive layer.

44. 42. The method of claim 41, wherein the partial OLED stack is a bottom-emitting partial OLED stack.

45. 42. The method of claim 41, wherein the metal compound comprises a silver (Ag) compound or an aluminum (Al) compound.

46. 42. The method of claim 41 , wherein the cathode is reflective.

47. The method of claim 41, wherein the cathode has a conductivity of 0.001 to 1.0 ohms per square per mil.

48. The partial OLED stack is at least 1 cm above the substrate. ２ 42. The method of claim 41 , wherein the continuous area of

49. 42. The method of claim 41, wherein the partial OLED stack includes an anode comprising a material other than indium tin oxide (ITO).

50. the partial OLED stack is made up of a plurality of layers; The method further comprising:

42. The method of claim 41, further comprising fabricating the partial OLED stack using a solution based process to form each layer of the partial OLED stack, including depositing a transparent conductive layer using a solution based process to form an anode for the partial OLED stack.

51. 42. The method of claim 41 , wherein the solution containing the metal compound is deposited using a roll-to-roll process.

52. 42. The method of claim 41, wherein the metal compound comprises a conductive particle functionalized to be soluble in the aliphatic solvent.

53. The partial OLED stack is made up of a number of layers, 42. The method of claim 41, wherein each layer of the plurality of layers of the partial OLED stack is insoluble in the aliphatic solvent.

54. The metal compound includes conductive particles, 42. The method of claim 41, wherein forming the conductive solid layer from the solution to form the cathode for the partial OLED stack comprises thermally curing the solution.

55. providing a substrate having an at least partial organic light emitting diode (OLED) stack disposed on a surface of the substrate; depositing a solution comprising a metal and a reducing agent over the partial OLED stack; and reducing said metal to precipitate said metal from said solution; The method includes:

56. The partial OLED stacks, in order of proximity to the substrate, are An anode; A hole injection layer; A hole transport layer; A light-emitting layer; an electron transport layer; An electron injection layer; 56. The method of claim 55, comprising:

57. 57. The method of claim 56, wherein the anode is a transparent conductive layer.

58. 56. The method of claim 55, wherein the partial OLED stack is a bottom-emitting partial OLED stack.

59. 56. The method of claim 55, wherein the metal comprises silver (Ag) or aluminum (Al).

60. 56. The method of claim 55, wherein the cathode is reflective.

61. 56. The method of claim 55, wherein the cathode has a conductivity of 0.001 to 1.0 ohms per square per mil.

62. The partial OLED stack is at least 1 cm above the substrate. ２ 56. The method of claim 55, wherein the continuous area is covered.

63. 56. The method of claim 55, wherein the partial OLED stack includes an anode comprising a material other than indium tin oxide (ITO).

64. the partial OLED stack is made up of a plurality of layers; The method further comprising:

56. The method of claim 55, further comprising fabricating the partial OLED stack using a solution based process to form each layer of the partial OLED stack, including depositing a transparent conductive layer using a solution based process to form an anode for the partial OLED stack.

65. The solution containing the metal and the reducing agent is deposited using a roll-to-roll process.

56. The method of claim 55,

66. the partial OLED stack is made up of a plurality of layers; the solution comprises a solvent; 56. The method of claim 55, wherein each layer of the plurality of layers of the partial OLED stack is insoluble in the solvent.

67. A substrate; a partial OLED stack disposed on a surface of the substrate, the partial OLED stacks including, in order of proximity to the substrate: An anode; one or more active layers; a cathode comprising a solid layer of sintered conductive particles; The device that contains

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