A thin film optoelectronic device

Abstract

This application provides a thin-film optoelectronic device, relating to the field of semiconductor technology. The thin-film optoelectronic device includes: a substrate, an electrode layer, a carrier layer, and a photoelectric conversion layer. The carrier layer is used for the transport of electrons and holes; the photoelectric conversion layer is used for the conversion of light energy into electrical energy based on the transport of electrons and holes. The electrode layer, carrier layer, and photoelectric conversion layer are deposited on the substrate to form a multilayered thin-film stack structure. By utilizing only electrophoretic deposition to prepare multiple functional coatings such as the electrode layer, carrier layer, and photoelectric conversion layer, the full-structure layer fabrication of thin-film optoelectronic devices such as LEDs, thin-film lasers, photovoltaic cells, and photodetectors can be achieved. The process is simple, reduces fabrication costs, shortens the fabrication cycle, and provides stable product quality. The method is flexible and can be used for large-area fabrication.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, and more specifically, to a thin-film optoelectronic device. Background Technology

[0002] Thin-film optoelectronic devices, including photovoltaic cells, photodetectors, and other photoelectric conversion devices, as well as light-emitting diodes (LEDs) and lasers, are typically closed structures composed of multiple layers of thin films vertically stacked between a bottom electrode and a top electrode. Research and fabrication of thin-film optoelectronic devices are still in the developmental stage, with different fabrication techniques used for different functional coatings such as the negative electrode layer, electron injection layer, electron transport layer, hole blocking layer, light-emitting / active layer, electron blocking layer, hole transport layer, hole injection layer, and positive electrode layer.

[0003] Currently, commonly used fabrication techniques include atomic force deposition (ALD), spin coating, thermal evaporation, magnetron sputtering, and electrophoretic deposition (EPD). Typically, the fabrication of a complete device requires two or more of these techniques. Switching between different fabrication techniques, sample transfer, and environmental changes during the fabrication process can all increase fabrication costs, lengthen the fabrication cycle, and reduce product quality. Summary of the Invention

[0004] In view of this, the purpose of this application is to provide a thin-film optoelectronic device, which includes a substrate, an electrode layer, a carrier layer, and a photoelectric conversion layer. The photoelectric conversion layer can convert light energy into electrical energy according to the interaction of holes and electrons. The electrode layer, the carrier layer, and the photoelectric conversion layer are deposited on the substrate by electrophoretic deposition to form a multilayer thin film stacked structure. The entire preparation process only requires electrophoretic deposition technology, thereby solving the above-mentioned technical problems of "increased preparation cost, longer preparation cycle and decreased product quality".

[0005] In a first aspect, embodiments of this application provide a thin-film optoelectronic device, the thin-film optoelectronic device comprising: a substrate, an electrode layer, a carrier layer, and a photoelectric conversion layer; the carrier layer is used for the transport of electrons and holes; the photoelectric conversion layer is used for the conversion of light energy and electrical energy according to the transport of electrons and holes; wherein the electrode layer, the carrier layer, and the photoelectric conversion layer are formed into a multilayer thin film stack structure on the substrate by electrophoretic deposition.

[0006] In the above process, by using only electrophoretic deposition to prepare multiple functional coatings such as electrode layer, charge carrier layer and photoelectric conversion layer, it is possible to prepare thin film optoelectronic devices with full structure, reduce preparation cost, shorten preparation cycle and ensure stable product quality.

[0007] Optionally, the photoelectric conversion layer is used to convert electrical energy into light energy based on the transport of electrons and holes; the photoelectric conversion layer includes a light-emitting layer; the thin-film optoelectronic device includes an LED and a thin-film laser.

[0008] In the above process, by using only electrophoretic deposition to prepare multiple functional coatings such as electrode layer, charge carrier layer and light-emitting layer, it is possible to prepare thin-film optoelectronic devices with full structure such as LED and thin-film laser, thereby reducing preparation cost, shortening preparation cycle and ensuring stable product quality.

[0009] Optionally, the charge carrier layer includes an electron transport layer and a hole transport layer; the electron transport layer and the hole transport layer are prepared by electrophoretic deposition of a suspension, the suspension including a solute and a solvent; the solute of the suspension of the electron transport layer includes metal nano-oxides; the solute of the suspension of the hole transport layer includes organic polymers and metal nano-oxides; the solvent includes organic solvents and inorganic solvents.

[0010] In the above process, by preparing a carrier layer by using a suspension with specific solutes and solvents and electrophoretically depositing the suspension, it is possible to prepare electron transport layers and hole transport layers in full-structure thin-film optoelectronic devices such as LEDs and thin-film lasers. This reduces preparation costs, shortens the preparation cycle, and ensures stable product quality.

[0011] Optionally, the metal nano-oxide includes: zinc oxide nanoparticles, zinc oxide nanoparticles, and zinc oxide aluminum nanoparticles.

[0012] In the above-mentioned process, by equipping a suspension of metal nano-oxides such as zinc oxide nanoparticles, zinc oxide nanoparticles, and zinc oxide aluminum nanoparticles as specific solutes, and using the electrophoretic deposition of the suspension to prepare the carrier layer, the electron transport layer in the full-structure thin-film optoelectronic devices such as LEDs and thin-film lasers can be effectively prepared, improving the efficiency of electron transfer and transmission, and is beneficial for preparing high-performance optoelectronic devices.

[0013] Optionally, the organic polymer includes: polyvinylcarbazole, hydroxyquinoline neodymium, triphenyldiamine, and triphenylamine.

[0014] In the above-mentioned process, by using organic polymers such as polyvinylcarbazole, hydroxyquinoline neodymium, triphenyldiamine, and triphenylamine as specific solutes in the suspension, the carrier layer can be prepared by electrophoretic deposition of the suspension. This method can effectively prepare the hole transport layer in full-structure thin-film optoelectronic devices such as LEDs and thin-film lasers, improve the efficiency of electron-hole interaction, and facilitate the preparation of high-performance optoelectronic devices.

[0015] Optionally, the organic solvent includes toluene, ethanol, isopropanol, and n-hexane; the inorganic solvent includes deionized water.

[0016] In the above-mentioned process, organic solvents include, but are not limited to, toluene, ethanol, isopropanol, and n-hexane; inorganic solvents include, but are not limited to, deionized water. By preparing a suspension of organic / inorganic solvents such as toluene, ethanol, isopropanol, n-hexane, and deionized water as specific solvents, and using the electrophoretic deposition method to prepare the carrier layer, the complete fabrication of full-structure thin-film optoelectronic devices such as LEDs and thin-film lasers can be further realized. Using the same solvent can save raw materials and improve the efficiency of electrophoretic deposition.

[0017] Optionally, the electrode layer is prepared by electrophoretic deposition of a suspension, wherein the solute of the suspension includes metal nanoparticles and metal nanowires.

[0018] In the above-mentioned process, by equipping a suspension with metal nanoparticles and metal nanowires as specific solutes, and using an electrophoretic deposition method to prepare the electrode layer, the electrode layer in full-structure thin-film optoelectronic devices such as LEDs and thin-film lasers can be effectively prepared, reducing the preparation cost and shortening the preparation cycle, which is beneficial for preparing optoelectronic devices with excellent performance.

[0019] Optionally, the light-emitting layer is prepared by electrophoretic deposition of a suspension, wherein the solute of the suspension includes perovskite materials, semiconductor nanocrystals, and micron-sized materials.

[0020] In the above-mentioned process, by using a suspension of nanomaterials or micromaterials such as perovskite materials, semiconductor nanocrystals, and micron materials as specific solutes, and using electrophoretic deposition of the suspension to prepare the light-emitting layer, the complete fabrication of full-structure thin-film optoelectronic devices such as LEDs and thin-film lasers can be further realized. The process is simple, reduces the preparation cost, shortens the preparation cycle, and is conducive to the preparation of optoelectronic devices with excellent light-emitting performance.

[0021] Optionally, the concentration of the suspension is 0.1 mg / ml to 300 mg / ml.

[0022] In the above process, by using a suspension with a concentration of 0.1 mg / ml to 300 mg / ml, and by preparing the carrier layer, light-emitting layer and electrode layer by electrophoretic deposition of the suspension, the complete fabrication of thin-film optoelectronic devices with full structure such as LEDs and thin-film lasers can be further realized. The process is simple, has good stability and high success rate.

[0023] Optionally, the voltage for preparing the suspension by electrophoretic deposition is 1V to 2000V, the current is 1mA to 10A, and the deposition time is 1s to 3600s.

[0024] In the above process, by setting electrophoretic parameters such as voltage of 1V to 2000V, current of 1mA to 10A, and deposition time of 1s to 3600s, the carrier layer, light-emitting layer, and electrode layer can be deposited using an electrophoretic deposition device. This allows for the complete fabrication of full-structure thin-film optoelectronic devices such as LEDs and thin-film lasers. The process is simple, highly versatile, and has a high success rate.

[0025] Optionally, the process of preparing the suspension by electrophoretic deposition includes: attaching two substrates to the positive and negative electrodes of an electrophoretic deposition apparatus; setting the deposition parameters of the electrophoretic deposition apparatus and starting the electrophoretic deposition apparatus; immersing the substrates in the prepared suspension for deposition; and attaching multiple target layers to the corresponding positive or negative electrode substrates according to the different properties of the solute in the suspension; wherein the deposition parameters include: sinking rate, pulling rate, deposition time, voltage, and current; and the target layers include: an electrode layer, a carrier layer, and a light-emitting layer.

[0026] In the above process, by equipping carrier layers (electron transport layer and hole transport layer), light-emitting layer and electrode layer with suspensions of different solutes, the suspension is deposited using an electrophoretic deposition device, and then multiple functional coatings are deposited at the electrodes, thereby realizing the complete structure fabrication of full-structure thin-film optoelectronic devices such as LEDs and thin-film lasers. The process is simple, reduces the preparation cost, shortens the preparation cycle, and is flexible and can be used for large-area fabrication.

[0027] Optionally, the process of preparing the suspension by electrophoretic deposition further includes: baking the target layer attached to the corresponding positive or negative electrode substrate; wherein the baking temperature of the baking treatment includes 20°C to 400°C; and the baking time of the baking treatment includes 1 min to 300 min.

[0028] In the above process, baking can solidify the deposited new film layer, making the film layer less likely to fall off and improving the success rate of preparation.

[0029] Optionally, the solvents of the suspensions used in adjacent layers of the plurality of target layers are orthogonal.

[0030] In the above process, solvent orthogonality can avoid the risk of the previous solute being corroded or dissolved off, thereby increasing the stability of the connection between layers of the thin film optoelectronic device prepared by electrophoretic deposition, and forming some special architectures to achieve specific functional features of the thin film optoelectronic device.

[0031] Optionally, the photoelectric conversion layer is used to convert light energy into electrical energy based on the transmission of electrons and holes; the photoelectric conversion layer includes an active layer, and the thin-film optoelectronic device includes a photovoltaic cell and a photodetector.

[0032] In the above process, multiple functional coatings such as electrode layers, charge carrier layers, and active layers are prepared by electrophoretic deposition, thereby enabling the fabrication of thin-film optoelectronic devices with complete structures such as photovoltaic cells and photodetectors. This reduces the fabrication cost, shortens the fabrication cycle, and ensures stable product quality.

[0033] Optionally, the carrier layer includes an electron transport layer and a hole transport layer; the electron transport layer and the hole transport layer are prepared by electrophoretic deposition of a suspension, the suspension including a solute and a solvent; the solute of the electron transport layer suspension includes metal nano-oxides; the solute of the hole transport layer suspension includes organic polymers and metal nano-oxides; the solvent includes organic solvents and inorganic solvents.

[0034] In the above process, by preparing a carrier layer by using a suspension with specific solutes and solvents and electrophoretically depositing the suspension, it is possible to prepare electron transport layers and hole transport layers in all-structure thin-film optoelectronic devices such as photovoltaic cells and photodetectors. This reduces preparation costs, shortens the preparation cycle, and ensures stable product quality.

[0035] Optionally, the electrode layer is prepared by electrophoretic deposition of a suspension, wherein the solute of the suspension includes metal nanoparticles and metal nanowires.

[0036] In the above-mentioned process, by using a suspension of metal nanoparticles and metal nanowires as specific solutes, and by using electrophoretic deposition of the suspension to prepare the electrode layer, the electrode layer in the full-structure thin-film optoelectronic device such as photovoltaic cell and photodetector can be effectively prepared, reducing the preparation cost and shortening the preparation cycle, which is beneficial for preparing optoelectronic devices with excellent performance.

[0037] Optionally, the active layer is prepared by electrophoretic deposition of a suspension, wherein the solute of the suspension includes perovskite materials, semiconductor nanocrystals, and micron-sized materials.

[0038] In the above-mentioned process, by using a suspension of nanomaterials or micromaterials such as perovskite materials, semiconductor nanocrystals, and micron materials as specific solutes, and using electrophoretic deposition of the suspension to prepare the active layer, the complete fabrication of full-structure thin-film optoelectronic devices such as photovoltaic cells and photodetectors can be further realized. The process is simple, reduces the preparation cost, shortens the preparation cycle, and is conducive to the preparation of optoelectronic devices with excellent electrical performance.

[0039] Optionally, the process of preparing the suspension by electrophoretic deposition includes: attaching two substrates to the positive and negative electrodes of an electrophoretic deposition apparatus; setting the deposition parameters of the electrophoretic deposition apparatus and starting the apparatus; immersing the substrates in the prepared suspension for deposition; and attaching multiple target layers to the corresponding positive or negative electrode substrates according to the different properties of the solute in the suspension; wherein the deposition parameters include: sinking rate, pulling rate, deposition time, voltage, and current; and the target layers include: electrode layer, carrier layer, and active layer.

[0040] In the above-mentioned process, by equipping carrier layers (electron transport layer and hole transport layer), active layer and electrode layer with suspensions of different solutes, the suspension is deposited using an electrophoretic deposition device, and then multiple functional coatings are deposited at the electrodes, thereby realizing the complete structure fabrication of thin-film optoelectronic devices such as photovoltaic cells and photodetectors. The process is simple, reduces the preparation cost, shortens the preparation cycle, and is flexible and can be used for large-area fabrication.

[0041] Optionally, the substrate has a preset pattern, and the carrier layer, photoelectric conversion layer, and electrode layer are deposited by electrophoretic deposition on the preset pattern; wherein the preset pattern is generated by thin film preparation technology and mask preparation.

[0042] In the above process, various patterns can be generated in the deposition area of ​​the substrate by using common thin film preparation techniques combined with photomasks. The diameter can range from 10 nanometers to 5 cm, thereby achieving precise control over the deposition area and patterns, and providing scalability.

[0043] Optionally, the charge carrier layer includes: an electron transport layer and a hole transport layer; wherein the multilayer thin film stacked structure is formed by electrophoretically depositing a hole transport layer on a substrate, electrophoretically depositing a photoelectric conversion layer on the hole transport layer, electrophoretically depositing the electron transport layer on the photoelectric conversion layer, and electrophoretically depositing an electrode layer on the electron transport layer; and / or, the multilayer thin film stacked structure is formed by electrophoretically depositing an electron transport layer on a substrate, electrophoretically depositing a photoelectric conversion layer on the electron transport layer, electrophoretically depositing the hole transport layer on the photoelectric conversion layer, and electrophoretically depositing an electrode layer on the hole transport layer.

[0044] In the above process, by adjusting the order of preparing the carrier layer, electrode layer and photoelectric conversion layer, and by electrophoretically depositing multiple functional coatings in an upright or inverted manner, optoelectronic devices composed of various thin film stacked structures can be realized, providing a broad prospect for the widespread application of the devices in the future.

[0045] Optionally, the carrier layer further includes: a hole injection layer, an electron blocking layer, an electron injection layer, and a hole blocking layer; wherein the hole injection layer and the electron injection layer are prepared by electrophoretic deposition of a suspension in which metal oxide nanoparticles or polymer materials are immersed as solutes; and the electron blocking layer and the hole blocking layer are prepared by dip coating of a suspension in which metal oxide nanoparticles or polymer materials are immersed as solutes.

[0046] In the above implementation process, for the special carrier layers such as the hole injection layer, electron blocking layer, electron injection layer and hole blocking layer, specific solutes and solvents are used as electrophoretic solutions for deposition preparation. Among them, the dip-coating film can be obtained by adjusting other deposition parameters without applying voltage and current during the electrophoretic deposition process. This can realize a variety of thin film stacked structure optoelectronic devices containing special functional layers, making carrier injection more balanced and improving the photoelectric efficiency of the device.

[0047] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, specific embodiments are described below in conjunction with the accompanying drawings. Attached Figure Description

[0048] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0049] Figure 1 This is a schematic diagram of the structure of a thin-film optoelectronic device provided in an embodiment of this application;

[0050] Figure 2 A flowchart illustrating an electrophoretic deposition method provided in an embodiment of this application;

[0051] Figure 3 This is a schematic diagram of an electrophoretic deposition apparatus provided in an embodiment of this application;

[0052] Figure 4 A schematic diagram of an inverted thin-film optoelectronic device structure provided in an embodiment of this application;

[0053] Figure 5A schematic diagram of a preset pattern provided for an embodiment of this application;

[0054] Figure 6 This is a schematic diagram of an inverted thin-film optoelectronic device provided in an embodiment of this application.

[0055] Icons: 10-Thin film optoelectronic device; 11-Substrate; 12-Carrier layer; 13-Photoelectric conversion layer; 14-Electrode layer. Detailed Implementation

[0056] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0057] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0058] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. The terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. The terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0059] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0060] In the description of the embodiments of this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship. In the description of the embodiments of this application, the term "multiple" refers to two or more (including two). Similarly, "multiple groups" refers to two or more groups (including two groups), and "multiple pieces" refers to two or more pieces (including two pieces). In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0061] With the continuous exploration of semiconductor materials, thin-film functional optoelectronic devices have emerged. After years of research, thin-film functional optoelectronic devices have developed rapidly. Typical thin-film functional optoelectronic devices include quantum dot LEDs and thin-film solar cells. The classic structure of these devices includes the following parts: negative electrode, electron transport layer, photoelectric conversion layer, hole transport layer, and positive electrode. Currently, the research and manufacturing of thin-film functional optoelectronic devices are still in the developmental stage. Different functional coatings use different fabrication techniques. For the fabrication of thin-film functional optoelectronic devices, a complete device typically requires two or more techniques, which is not conducive to the fabrication of optoelectronic devices.

[0062] Currently, the commonly used fabrication techniques for various coatings of this thin-film functional optoelectronic device include: atomic force deposition (ALD), spin coating, thermal evaporation, and magnetron sputtering.

[0063] Electrophoretic deposition (EPD) is a method for creating a coating or thin film on a conductive object. Small particles suspended in a liquid typically carry either a positive or negative charge. If a direct current is applied to the suspension using an electrode, the particles will move towards the electrode with the opposite charge. Electrophoresis is commonly used in biochemical analysis and has become an important component of many industrial processes. Electrophoretic deposition, also known as electrophoretic coating or electron coating, uses the object to be coated as an electrode, depositing particles with opposite charges onto it to form a layer. Depending on whether a positive or negative electrode is used, the process can be called anodic electrodeposition or cathodic electrodeposition, respectively. If the particles are generally electrically neutral, compounds may bond to them, thus generating a charge in the suspension state. The electrorepulsive forces generated between the particles also prevent them from agglomerating.

[0064] The inventors of this application have noted that the fabrication of a complete optoelectronic device requires two or more of the following techniques: atomic force deposition, spin coating, thermal evaporation, magnetron sputtering, and electrophoretic deposition. Currently, researchers have proposed vacuum evaporation for constructing perovskite thin films using the co-evaporation of two precursors (PbCl2 and CH3NH3I). While the resulting films exhibit satisfactory perovskite film coverage and uniformity, this technique requires high vacuum and is therefore very energy-intensive in scale-up methods. Spin coating can be used to prepare coatings other than electrodes, but the solution must be orthogonal, resulting in unstable coating quality and low solvent selectivity, thus limiting the choice of spin coating materials and significantly restricting applications. Forming metal compound layers on a substrate, such as by electrodepositing a PbO layer which then reacts with a suitable precursor material to form a perovskite coating, can create thin layers. However, the deposition kinetics for producing suitable thick layers of metal compounds on the substrate are slow (typically greater than 1 hour), thus limiting the commercial scalability of these types of processes.

[0065] Electrophoretic deposition is an effective method for depositing thin films on conductive substrates, offering excellent control over film thickness, uniformity, and deposition rate. Its most attractive feature is its low cost due to its relatively low requirements for raw materials and equipment, making it ideal for large-scale production. Furthermore, electrophoretic deposition allows for easy low-temperature film formation, making it a promising method for fabricating optoelectronic devices. However, the preparation of carrier layers using electrophoretic deposition has not yet been achieved.

[0066] In view of this, the inventors of this application propose a method for preparing a functional coating based on long-term research on optoelectronic device fabrication. This method involves placing the substrate to be prepared and a reference substrate connected to an electrophoretic deposition apparatus into a suspension corresponding to the carrier layer. By setting appropriate deposition parameters, a specific current and voltage are applied to the substrate and reference substrate through the electrophoretic deposition apparatus. This causes the solutes in the suspensions corresponding to the carrier layer, electrode layer, and photoelectric conversion layer to move towards the substrate to be prepared, thereby forming the carrier layer, electrode layer, and photoelectric conversion layer on the substrate. This achieves the fabrication of the carrier layer, electrode layer, and photoelectric conversion layer through electrophoretic deposition. Therefore, this application provides a thin-film optoelectronic device 10, in which multiple layers are prepared by electrophoretic deposition. The entire fabrication process uses only one electrophoretic deposition apparatus, is simple to operate, has a short processing time, and uses simple parameters, making it versatile.

[0067] Please see Figure 1 , Figure 1 A thin-film optoelectronic device 10 is provided in this application embodiment. The thin-film optoelectronic device 10 includes: a substrate 11, an electrode layer 14, a carrier layer 12, and a photoelectric conversion layer 13. The carrier layer 12 is used for the transport of electrons and holes. The photoelectric conversion layer 13 is used for the conversion of light energy and electrical energy according to the transport of electrons and holes. The electrode layer 14, the carrier layer 12, and the photoelectric conversion layer 13 are formed on the substrate 11 by electrophoretic deposition to form a multilayer thin film stack structure.

[0068] For example, the substrate 11 can be a conductive substrate material such as ITO glass or FTO glass, or a metal oxide such as silicon semiconductor, ZnO, MgO, or Al2O3, a metal element such as Au, Ag, Cu, or Al, or other types of conductive or semiconductor thin film substrate 11. The electrode layer 14 can include a bottom electrode and a top electrode, or a positive (anode) electrode and a negative (cathode) electrode, and the electrode material is usually gold, silver, aluminum, copper, or other metallic conductive materials.

[0069] Carrier layer 12 can contain two types of charge carriers: negatively charged free electrons and positively charged free holes. Under thermal equilibrium, the generation rate of electrons and holes equals the recombination rate, maintaining a balance between their concentrations. Under external conditions (such as illumination), additional non-equilibrium charge carriers, i.e., electron-hole pairs, are generated. After the external conditions are removed, because the recombination rate is greater than the generation rate, the non-equilibrium charge carriers gradually recombine and disappear, eventually returning to thermal equilibrium. The recombination process can be broadly divided into two types: direct recombination occurs when electrons directly jump between the conduction band and valence band, causing the disappearance of an electron-hole pair; indirect recombination occurs when electron-hole pairs recombine through energy levels (recombination centers) in the band gap.

[0070] The photoelectric conversion layer 13 can be used to convert light energy into electrical energy due to the interaction of electrons and holes during transport in semiconductors. The conversion of light energy into electrical energy can be as follows: sunlight shines on a semiconductor PN junction, forming new electron-hole pairs. Under the influence of the PN junction's electric field, holes flow from the N-region to the P-region, and electrons flow from the P-region to the N-region, forming a current when the circuit is connected. The conversion of electrical energy into light energy can be as follows: in the PN junction of certain semiconductor materials, when injected minority carriers recombine with majority carriers, excess energy is released in the form of light, thus directly converting electrical energy into light energy. When a reverse voltage is applied to the PN junction, minority carriers are difficult to inject, so no light is emitted. When it is in a forward operating state (i.e., a forward voltage is applied across its terminals), as current flows from the anode to the cathode, the semiconductor crystal emits light of different colors from ultraviolet to infrared, with the intensity of the light depending on the current.

[0071] Electrophoretic deposition (EPD), also known as electrophoretic coating or electronic coating, can be a method of creating a coating or thin film on a conductive object, or in some cases, a method of creating individual components and materials using a process called electrophoresis. Specifically, the object to be coated is used as an electrode, onto which particles with opposite charges are deposited to form a coating. During deposition, the migration of charged particles in the liquid towards the electrode is achieved through the influence of an electric current. Small particles suspended in a liquid typically carry either a positive or negative charge due to molecular interactions with molecules in the medium. If a direct current is applied to the suspension using an electrode, the particles will move towards the electrode with the opposite charge.

[0072] The thin-film optoelectronic device 10 can be a closed structure composed of multiple layers of thin films vertically stacked on a substrate 11, formed by sequentially fabricating the electrode layer 14, carrier layer 12, and photoelectric conversion layer 13 on the substrate 11 using the electrophoretic deposition method described above. Optionally, an ITO layer is first grown on the glass substrate 11, and then other layers are grown layer by layer. The growth method of each layer can be analogous to immersing the ITO in different solutions in sequence for multiple depositions. The solution contains solvent and nanoparticles corresponding to the layer. Direct current is applied to both sides for deposition. After deposition, the layer is pulled out, baked, and then placed in a subsequent solution, and so on, thereby depositing a structure of multiple stacked thin films. For example, the device structure can be from bottom to top as follows: ITO substrate 11, ETL layer (Electrotransmission layer), EML layer (Emission layer), HTL layer (Holetransmission layer), and Electrode layer (electrode layer 14), wherein the carrier layer 12 includes an electron transport layer and a hole transport layer.

[0073] By using only electrophoretic deposition to prepare multiple functional coatings such as electrode layer 14, carrier layer 12, and photoelectric conversion layer 13, the fabrication of a full-structure thin-film optoelectronic device 10 can be achieved, reducing fabrication costs, shortening the fabrication cycle, and ensuring stable product quality.

[0074] In one embodiment, the photoelectric conversion layer 13 is used to convert electrical energy into light energy based on the transport of electrons and holes; the photoelectric conversion layer 13 includes a light-emitting layer; the thin-film optoelectronic device 10 includes an LED and a thin-film laser.

[0075] For example, an LED, or light-emitting diode, can be a microLED or a MiniLED. Such devices convert electrical energy into light energy. Electrons are generated in the electron transport layer and holes are generated in the hole transport layer. Electrons and holes combine in the light-emitting layer, releasing energy of several electron volts (eV). When the energy meets the emission spectrum, different colors of light are produced.

[0076] Thin-film lasers can be commonly used laser diodes. The phenomenon of spontaneous recombination of electrons and holes on both sides of the PN junction of the emitting layer to emit light is called spontaneous emission. When photons generated by spontaneous emission pass through a semiconductor, they can be excited to recombine with previously emitted electron-hole pairs, generating new photons. This phenomenon of photons inducing the recombination of excited charge carriers to emit new photons is called stimulated emission. If the injected current is large enough, a charge carrier distribution opposite to the thermal equilibrium state will be formed in the charge carrier layer 12, i.e., population inversion. When the charge carriers in the charge carrier layer 12 are in a large number of inversions, a small number of photons generated by spontaneous emission will generate induced radiation due to the reciprocating reflection of the two end faces of the resonant cavity, resulting in frequency-selective resonance positive feedback, or gain at a certain frequency. When the gain is greater than the absorption loss, coherent light with good spectral lines—laser—can be emitted from the PN junction of the emitting layer.

[0077] By using only electrophoretic deposition to prepare multiple functional coatings such as electrode layer 14, carrier layer 12, and light-emitting layer, it is possible to prepare thin-film optoelectronic devices 10 with full structure such as LEDs and thin-film lasers, thereby reducing preparation costs, shortening the preparation cycle, and ensuring stable product quality.

[0078] In one embodiment, the carrier layer 12 includes an electron transport layer and a hole transport layer; the electron transport layer and the hole transport layer are formed by electrophoretic deposition of a suspension, the suspension including a solute and a solvent; wherein, the solute of the suspension of the electron transport layer includes metal nano-oxide; the solute of the suspension of the hole transport layer includes organic polymers and metal nano-oxides; and the solvent includes organic solvents and inorganic solvents.

[0079] For example, the carrier layer 12 may specifically include an electron transport layer and a hole transport layer. A suspension can be a mixture in which substances distributed in a liquid material are not dissolved but merely dispersed; once the mixture stops oscillating, they precipitate, thus forming a non-uniform, heterogeneous mixture. The solid particles acting as solutes in the suspension generally have a particle size greater than 1 nm-10 μm, larger than colloids. The liquid material acting as a solvent can be a common organic or inorganic solvent, such as toluene, ethanol, isopropanol, or deionized water.

[0080] The solute used in the suspension for preparing the electron transport layer differs from that used in the suspension for preparing the hole transport layer. The former can be metal nano-oxides because these materials have high electron mobility; for example, ZnO has an electron mobility of 1*10⁻³ cm² / VS. The latter can be transparent conductive polymers, organic polymers, and metal nano-oxides. Examples of organic polymers include: poly(3,4-ethylenedioxythiophene) (PEDOT), a mixture of poly(3,4-ethylenedioxythiophene) and polystyrene sulfonate (PEDOT:PSS), poly(4,4-dioctylcyclopentazothiophene); P3HT, doped P3HT (poly(3-hexylthiophene-2,5-diyl)), and poly[N-9”-heptadecyl-2,7-carbazole-alternating-5,5-(4',7'-di-2-thienyl-2',1',3'-benzothiadiazole)] (PCDTBT). The following are examples of metal nanoparticles: poly[2,6-(4,4-bis(2-ethylhexyl)-4H-cyclopentano[2,1-b;3,4-b']dithiophene)-alternating-4,7(2,1,3-benzothiadiazole)] (PCPDTBT), poly(N-alkyl dione pyrrolopyrrolodithiophene[3,2-b]thiophene) (DPP-DTT), methyl [6,6]-phenyl-C61-butyrate (PC60BM), indene-C60 bisadduct (ICBA), spiro-OMeTAD, MoO3, etc.; the metal nano-oxides can be: nickel oxide, nickel magnesium oxide, nickel silver oxide, and other metal-doped nickel oxide nanoparticles, or tungsten oxide, vanadium oxide, and other metal oxide nanoparticles. The prepared suspension can be sealed and stored at a temperature of -5 to +3℃, depending on the properties of the solvent, and shaking should be avoided.

[0081] By using a suspension with specific solutes and solvents to prepare the carrier layer 12 by electrophoretic deposition of the suspension, the electron transport layer and hole transport layer in the full-structure thin-film optoelectronic device 10 such as LED and thin-film laser can be prepared, reducing the preparation cost, shortening the preparation cycle, and ensuring stable product quality.

[0082] In one embodiment, the metal nanooxide comprises: zinc oxide nanoparticles, zinc oxide nanoparticles, and zinc oxide aluminum nanoparticles.

[0083] For example, the solute in the suspension used to prepare the electron transport layer can be zinc oxide nanoparticles (ZnO), zinc oxide nanoparticles (ZMO), zinc aluminum oxide nanoparticles (AZO), or other metal nano-oxides. Using metal oxide nanoparticles as the electron transport layer allows for the effective utilization of their high carrier mobility and deep valence band positions, such as ZnO. Metal oxide nanomaterials can be doped with certain ions to form metal-doped nano-oxides; for example, ZnO nanomaterials can be doped with one of the ions selected from Ga, In, Al, and Mg to form corresponding doped materials, such as ZMO and AZO, thereby further enhancing carrier mobility.

[0084] By using a suspension of metal nano-oxides such as zinc oxide nanoparticles, zinc oxide nanoparticles, and zinc oxide aluminum nanoparticles as specific solutes, and preparing the carrier layer 12 by electrophoretic deposition of the suspension, the electron transport layer in the full-structure thin-film optoelectronic device 10, such as LED and thin-film laser, can be effectively prepared. This improves the efficiency of electron transfer and transmission, and is beneficial for preparing high-performance optoelectronic devices.

[0085] In one embodiment, the organic polymer comprises: polyvinylcarbazole, hydroxyquinoline neodymium, triphenyldiamine, and triphenylamine.

[0086] For example, the solute in the suspension used to prepare the hole transport layer can be polyvinylcarbazole (PVK), neodymium hydroxyquinoline (Ndq), triphenyldiamine (TPD), and triphenylamine (TCTA) or other organic polymers. Other examples include N'-bis-(1-naphthyl)-N,N'-biphenyl-1,1'-biphenyl-4,4'-diamine (NPB), poly[(9,9-dioctylfluorene-2,7-diyl)-co-(4,4-(N-(4-sec-butylphenyl)diphenylamine)] (TFB), TPB, etc. These materials possess characteristics such as good conductivity, high visible light transmittance, low sheet resistance, strong bonding, and a flat surface.

[0087] By using organic polymers such as polyvinylcarbazole, hydroxyquinoline neodymium, triphenyldiamine, and triphenylamine as specific solutes in a suspension, a method for preparing carrier layer 12 by electrophoretic deposition of the suspension can be used to effectively prepare hole transport layers in full-structure thin-film optoelectronic devices 10 such as LEDs and thin-film lasers. This improves the efficiency of electron-hole interaction and is beneficial for preparing high-performance optoelectronic devices.

[0088] In one embodiment, the organic solvent includes toluene, ethanol, isopropanol, and n-hexane; the inorganic solvent includes deionized water.

[0089] For example, the suspension solvent for preparing the electron transport layer can be toluene, ethanol, isopropanol, n-hexane, deionized water, or other solvents; the suspension solvent for preparing the hole transport layer can be toluene, ethanol, or various conductive solvents such as chlorobenzene, n-hexane, deionized water, n-octane, 1,4-dioxane, p-Xylene, and o-Xylene. Depending on the different properties of the solvents, suspensions suitable for different sealed storage temperatures can be prepared.

[0090] By using a suspension containing specific solvents such as toluene, ethanol, isopropanol, n-hexane, and deionized water to prepare the carrier layer 12 via electrophoretic deposition, the complete fabrication of thin-film optoelectronic devices 10 with full structure, such as LEDs and thin-film lasers, can be further realized. Using the same solvent throughout can save raw materials and improve the efficiency of electrophoretic deposition.

[0091] In one embodiment, the electrode layer 14 is prepared by electrophoretic deposition of a suspension, the solute of which includes metal nanoparticles and metal nanowires.

[0092] For example, the solute in the suspension used to prepare the electrode layer 14 can be gold, silver, aluminum, copper, or other metals, and can be in the form of nanoparticles or nanowires. The solvent in the suspension used to prepare the electrode layer 14 can be ethanol, deionized water, isopropanol, ethanolamine, or other conductive solvents, as well as some organic solvents such as toluene and chloroform. Among them, nanoparticles or nanowires are metastable intermediate substances between solids and molecules, and can be "third-state crystalline materials" other than crystalline and amorphous states, possessing unique small-size effects, quantum effects (including macroscopic quantum tunneling effects), surface effects, and interface effects.

[0093] By using a suspension containing metal nanoparticles and metal nanowires as specific solutes, and employing electrophoretic deposition of the suspension to prepare the electrode layer 14, the electrode layer 14 in the full-structure thin-film optoelectronic device 10, such as LEDs and thin-film lasers, can be effectively prepared. This reduces preparation costs, shortens the preparation cycle, and is beneficial for preparing high-performance optoelectronic devices.

[0094] In one embodiment, the light-emitting layer is prepared by electrophoretic deposition of a suspension, the solute of which includes perovskite materials, semiconductor nanocrystals, and micron-sized materials.

[0095] For example, the solute in the suspension used to prepare the luminescent layer can be a perovskite material, such as a perovskite compound or a mixed halide perovskite; wherein the mixed halide perovskite can be: CH3NH3MX3 or HC(NH2)2MX3, where X contains two or more of F, Cl, Br or I, CH3NH3MX3 can contain CH3NH3MClxI3-x, CH3NH3MI3-xClx or similar substances, CH3NH3MClxI3-x, CH3NH3MI3-xClx or similar substances can contain non-stoichiometric materials, wherein M is selected from at least one of Pb, Sn, Ge, Si, Ti, Bi or In, and M is preferably Pb.

[0096] Optionally, the perovskite material may comprise a perovskite precursor comprising a solution, the solution of which may comprise one or more perovskite precursor compounds dissolved in a solvent. The perovskite semiconductor forming the light-emitting layer may be a metal layer subsequently treated with an organic halide compound, i.e., applying at least one coating of metal M to a substrate to form a substrate, the metal M being selected from at least one of Pb, Sn, Ge, Si, Ti, Bi, or In; and converting the metal coating of the substrate into a perovskite layer by applying at least one perovskite precursor, wherein the perovskite precursor comprises at least one compound having the formula AX, or at least one reactive component for forming at least one compound having the formula AX, wherein A comprises an ammonium group or other nitrogen-containing organic cation and X is selected from at least one of F, Cl, Br, or I.

[0097] The perovskite precursor may comprise molecules crystallized in a perovskite structure. The perovskite precursor preferably comprises at least one compound having the formula AX, or at least one reactive component for forming at least one compound having the formula AX, wherein A comprises an ammonium group or other nitrogen-containing organic cation and X is selected from at least one of F, Cl, Br, or I. The term "perovskite" may refer to a material having a three-dimensional crystal structure associated with CaTiO3 or a material comprising a layer having a structure associated with CaTiO3. The structure of CaTiO3 may be represented by the formula AMX3, wherein A and M are cations of different sizes, and X is an anion. In many embodiments, M comprises a metal cation, and more preferably a divalent metal cation such as Ca²⁺, Sr²⁺, Cd²⁺, Cu²⁺, Ni²⁺, Mn²⁺, Fe²⁺, Co²⁺, Pd²⁺, Ge²⁺, Sn²⁺, Pb²⁺, Sn²⁺, Yb²⁺, and Eu²⁺. In some embodiments, the second cation may be selected from Sn²⁺, Pb²⁺, and Cu²⁺.

[0098] In the unit cell, the A cation is located at (0, 0, 0), the M cation at (1 / 2, 1 / 2, 1 / 2), and the X anion at (1 / 2, 1 / 2, 0). The A cation is typically larger than the M cation. When A, M, and X vary, different ion sizes can cause the structure of the perovskite material to deform from the structure adopted by CaTiO3 to a deformed structure with lower symmetry. If the material contains layers with a structure associated with CaTiO3, the symmetry will be even lower.

[0099] Furthermore, the suspension solute used to prepare the light-emitting layer of thin-film optoelectronic devices such as LEDs and thin-film lasers can be: a perovskite semiconductor capable of absorbing light and thereby generating free charge carriers; and / or a perovskite semiconductor that emits light by accepting and subsequently recombinizing charges (both electrons and holes) that emit light. Therefore, the perovskite material used is typically a light-absorbing and / or light-emitting perovskite. The perovskite semiconductor used in this application can be a perovskite that acts as an n-type electron transport semiconductor when light-doped, or it can be a perovskite that acts as a p-type hole transport semiconductor when light-doped. Therefore, the perovskite can be n-type or p-type, or it can be an intrinsic semiconductor. Preferably, the perovskite used can be a perovskite that acts as an n-type electron transport semiconductor when light-doped.

[0100] The solute in the suspension used to prepare the luminescent layer can be semiconductor nanocrystals, quantum dots, quantum rods, nanowires, nanosheets, and other nanomaterials or micromaterials. For example, semiconductor nanocrystals can be CdSe, CdS, or core-shell structured CdSe-ZnS, CdSe-CdS quantum dots (one-dimensional nanomaterials) or quantum rods (two-dimensional nanomaterials).

[0101] The solvent for preparing the luminescent layer can be an organic solvent such as toluene, n-hexane, n-octane, chloroform, tri-n-octylphosphonic acid, or octadecene, or an inorganic solvent, or a mixture of several solvents. The prepared suspension should be sealed and stored in an airtight container.

[0102] Specifically, because the surface of the aforementioned nanocrystals is covered with a large number of organic ligands, such as tetradecyl phosphate and octadecyl phosphate, they must be dissolved in organic solvents such as toluene or n-hexane before preparing the suspension. Then, ethanol or isopropanol (organic solvent: alcohol = 1:2 to 1:5) is added and mixed thoroughly. The mixture is then centrifuged and washed 2-10 times to perform ligand exchange before electrophoretic deposition. The principle and method of ligand exchange is to use organic ligand solutions with shorter carbon chains, such as tri-n-octylphosphine (an acid with 8 carbons) and octanoic acid (8 carbons), to dissolve the luminescent layer material. The solution is shaken until homogeneous and free of agglomeration or flocculent material, and then sonicated for 10-60 minutes. Then, organic solvent and alcohol are added sequentially, following the same method, and the mixture is washed 2-10 times before finally preparing a suspension for use.

[0103] By using a suspension of nanomaterials or micromaterials such as perovskite, semiconductor nanocrystals, and micron-sized materials as specific solutes, and preparing the light-emitting layer by electrophoretic deposition of the suspension, the complete fabrication of full-structure thin-film optoelectronic devices 10 such as LEDs and thin-film lasers can be further realized. The process is simple, reduces the preparation cost, shortens the preparation cycle, and is conducive to the preparation of optoelectronic devices with excellent light-emitting performance.

[0104] In one embodiment, the concentration of the suspension is 0.1 mg / ml to 300 mg / ml.

[0105] For example, the concentration of the suspension used to prepare the carrier layer 12, the light-emitting layer, and the electrode layer 14 can be various concentrations, such as 0.1 mg / ml, 0.2 mg / ml, 0.3 mg / ml, 0.4 mg / ml…0.8 mg / ml…30 mg / ml…100 mg / ml, 200 mg / ml, and 300 mg / ml. The optimal concentration for the light-emitting layer is 0.8 mg / ml, for the electron transport layer and the hole transport layer it is 30 mg / ml, and for the electrode layer it is 20–30 mg / ml. Suspensions at these concentrations exhibit good stability and, under the influence of a DC electric field, allow charged particles in the suspension to move towards the electrode with the opposite polarity, ultimately depositing a dense thin film at the electrode.

[0106] By using a suspension with a concentration of 0.1 mg / ml to 300 mg / ml, and preparing the carrier layer 12, light-emitting layer, and electrode layer 14 by electrophoretic deposition of the suspension, the complete fabrication of thin-film optoelectronic devices 10 with full structure such as LEDs and thin-film lasers can be further realized. The process is simple, has good stability, and has a high success rate.

[0107] In one embodiment, the voltage for preparing the suspension by electrophoretic deposition is 1V to 2000V, the current is 1mA to 10A, and the deposition time is 1s to 3600s.

[0108] For example, the voltage of the electrophoretic deposition apparatus for preparing the carrier layer 12, light-emitting layer, and electrode layer 14 by electrophoretic deposition of the suspension can be set to any value such as 1V, 2V, 3V…100V…120V…300V…1000V…2000V. The commonly used voltage in the laboratory is 300V to 1000V, and the optimal voltage is 1000V. Similarly, the current can be set to any value in the range of 1mA to 10A, and the deposition time can be set to any value in the range of 1s to 3600s. Setting appropriate electrophoretic parameters such as current, voltage, and deposition time is beneficial for providing a suitable electric field force so that the charged particles in the suspension are deposited into a dense film at the electrode.

[0109] By setting electrophoretic parameters such as voltage from 1V to 2000V, current from 1mA to 10A, and deposition time from 1s to 3600s, the carrier layer 12, light-emitting layer, and electrode layer 14 can be deposited using an electrophoretic deposition device. This allows for the complete fabrication of thin-film optoelectronic devices 10 with full structure, such as LEDs and thin-film lasers. The process is simple, versatile, and has a high success rate.

[0110] Please see Figure 2 , Figure 2 This application provides a basic flowchart of an electrophoretic deposition method. In this embodiment, the process of preparing a suspension by electrophoretic deposition may specifically include:

[0111] Step 100: Attach the two substrates 11 to the positive and negative electrodes of the electrophoretic deposition apparatus;

[0112] Step 110: Set the deposition parameters of the electrophoretic deposition apparatus and start the electrophoretic deposition apparatus;

[0113] Step 120: Immerse the substrate 11 in the prepared suspension for deposition;

[0114] Step 130: Based on the different properties of the solute in the suspension, attach multiple target layers to the corresponding positive electrode substrate 11 or negative electrode substrate 11.

[0115] The deposition parameters include: sinking rate, pulling rate, deposition time, voltage, and current; the target layers include: electrode layer 14, carrier layer 12, and luminescent layer.

[0116] For example, electrophoretic deposition can be a process in which charged particles in a stable suspension are driven by a direct current electric field to move towards an electrode with the opposite polarity, thus depositing a thin film on the electrode surface. Figure 3 As shown, the basic components of the electrophoretic deposition apparatus may include: an electrophoresis tank, a power supply, and a pair of electrode substrates 11, namely, an anode (positive) electrode and a cathode (negative) electrode. The electrophoresis tank can be a quartz glass beaker of a certain volume; the power supply can be a common adjustable DC power supply with a maximum range of 2000V and 10A; the anode and cathode can be Au or Cu sheets, and the distance between the positive and negative electrodes can be freely adjusted; the solvent for the electrophoretic solution can be a 99.8% ethanol solution, or a suspension solvent corresponding to the aforementioned carrier layer 12, light-emitting layer, and electrode layer 14, and the solute can be the suspension solute corresponding to the aforementioned carrier layer 12, light-emitting layer, and electrode layer 14.

[0117] Optionally, the electrophoretic deposition of the carrier layer 12 (electron transport layer and hole transport layer), the light-emitting layer, and the electrode layer 14 is achieved through the following basic processes, thereby realizing the complete fabrication of the full-structure thin-film optoelectronic device 10, such as an LED or thin-film laser. For example: Figure 4As shown, (1) the electron transport layer is prepared by depositing ETL on the ITO substrate 11, i.e., the ITO / ETL sample preparation can be as follows:

[0118] Two conductive substrates 11 (ITO glass) are attached to the positive and negative electrodes of the electrophoretic deposition apparatus, respectively. The voltage is adjusted from 1V to 2000V, the sinking and pulling rates are set from 10 to 1000mm / min, the deposition time is set from 1 to 3600s, and the current is set from 1mA to 10A. Then, the start button is clicked. The substrate 11 will automatically rotate and immerse itself in the electron transport layer suspension. Under the control of the set voltage, current, and time, the deposition is completed. Then, the substrate will automatically lift off the suspension and return to its original position. The sample is removed from the negative / positive electrode and can be baked at 120℃ for 10 minutes. This completes the preparation of the ITO / ETL sample.

[0119] The final electron transport layer can achieve a controllable thickness ranging from 10nm to 3mm. In principle, ETL material will be deposited on both the positive and negative electrodes. However, due to differences in materials, voltage, current, deposition time, and solution concentration, the deposition quality on the positive and negative electrodes will be inconsistent. The specific deposition sample can be selected according to the actual setting parameters. For quantum dot LEDs, the suspension concentration C = 20mg / ml, the suspension solute can be ZMO, the voltage can be 300V, the current can be 1.2mA, and the deposition time can be 120s. Finally, a dense and uniform ETL coating film will be deposited on the ITO substrate 11 at the positive electrode.

[0120] (2) Preparation of the emissive layer (EML): Further deposition is performed on the ITO / ETL sample prepared above. That is, the ITO / ETL / EML can be prepared as follows:

[0121] For the nanorod suspension, the ITO / ETL sample prepared in the previous step should first be attached to the negative electrode of the electrophoretic deposition device. For quantum dots or other perovskite materials, the placement on the positive or negative electrode should be determined according to the material properties. Then, a conductive ITO, FTO, or other conductive material substrate 11 is placed on the positive electrode. Next, the deposition parameters are set, specifically the same as in (1), and the electrophoretic deposition device is started. The subsequent process is the same as in (1). In particular, before deposition, the luminescent layer suspension should be ultrasonically treated for 10-60 minutes. The final luminescent layer is attached to the negative electrode ITO / ETL sample, achieving a controllable thickness of 10 nm-1 mm. Optionally, after deposition, the sample is baked at 80-120°C for 15-60 minutes in an oxygen-isolated atmosphere.

[0122] (3) Preparation of the hole transport layer: Further deposition is performed on the prepared ITO / ETL / EML sample, i.e., the preparation of ITO / ETL / EML / HTL can be as follows:

[0123] Since the suspension solute uses NiO nanoparticles, the HTL layer will adhere to the positive electrode. The ITO / ETL / EML sample prepared in the previous step is attached to the positive electrode of the electrophoretic deposition equipment, and a conductive ITO, FTO, or other conductive material substrate 11 is placed on the negative electrode. Set the deposition parameters, the specific parameters are the same as in (1), start the electrophoretic deposition equipment, and the subsequent process is the same as in (1). In particular, only for inorganic HTL, such as NiO and WO, the HTL suspension needs to be ultrasonically treated for 10-60 minutes before deposition. The final HTL layer is attached to the ITO / ETL / EML sample on the positive electrode. For other materials, the solute should be attached to the positive or negative electrode according to its properties. The thickness can be controlled within the range of 10nm-3mm. Optionally, after deposition, the sample is baked at 80-120℃ for 15-60 minutes.

[0124] (4) Preparation of electrode layer 14: Further deposition is performed on the ITO / ETL / EML / HTL sample prepared above. That is, the preparation of ITO / ETL / EML / HTL / Electrode can be as follows:

[0125] Since the solute used in the suspension is gold nanoparticles, the Electrode layer will adhere to the positive electrode. The ITO / ETL / EML / HTL sample prepared in the previous step is attached to the positive electrode of the electrophoretic deposition equipment, and a conductive ITO, FTO, or other conductive material substrate 11 is placed on the negative electrode. The deposition parameters are set as in (1), and the electrophoretic deposition device is started. The subsequent process is the same as in (1). In particular, before deposition, the Electrode suspension is ultrasonically treated for 10-60 minutes. The final Electrode layer is attached to the ITO / ETL / EML / HTL sample on the positive electrode. For other materials, the attachment to the positive or negative electrode depends on the properties. The thickness can be controlled within the range of 10nm-3mm. Optionally, after deposition, the sample is baked at 80-150℃ for 15-60 minutes.

[0126] Furthermore, complete optoelectronic devices can be fabricated using only an electrophoretic deposition apparatus, and post-processing can be completed in situ within the electrophoresis tank chamber of the apparatus. Specifically, a heating element is installed in the EPD chamber, which is filled with inert gas for protection. Subsequent layer-by-layer deposition only requires switching between different suspensions to obtain complete devices. No equipment changes or sample transfers are needed, and the entire process takes only 30-60 minutes, which is faster and more reliable than conventional device fabrication methods that typically take at least 4 hours or even several days when different equipment is available.

[0127] By equipping carrier layer 12 (electron transport layer and hole transport layer), light-emitting layer and electrode layer 14 with suspensions of different solutes, the suspension is deposited using an electrophoretic deposition device, and then multiple functional coatings are deposited at the electrodes, thereby realizing the complete structure fabrication of the full-structure thin-film optoelectronic device 10 such as LED and thin-film laser. The process is simple, reduces the preparation cost, shortens the preparation cycle, and is flexible and can be used for large-area fabrication.

[0128] In one embodiment, the process of preparing the suspension by electrophoretic deposition further includes: baking the target layer attached to the corresponding positive electrode substrate 11 or negative electrode substrate 11; wherein the baking temperature of the baking treatment includes 20°C to 400°C; and the baking time of the baking treatment includes 1 min to 300 min.

[0129] For example, in the process of preparing the carrier layer 12 (electron transport layer and hole transport layer), light-emitting layer, and electrode layer 14 using the electrophoretic deposition apparatus described above, the successfully deposited sample can be baked in an oxygen-free atmosphere. The baking temperature can be one of various temperatures such as 20℃, 21℃, 22℃…80℃…120℃…150℃…400℃, with the optimal temperature being 80~120℃; the baking time can be one of various times such as 1min, 2min, 3min…15min…60min…300min, with the optimal time being 15~60min. Baking can solidify the deposited new thin film layer, making it less prone to peeling off and improving the preparation success rate.

[0130] In one embodiment, the solvents of the suspensions used in adjacent layers of a plurality of target layers are orthogonal.

[0131] For example, solvent orthogonality refers to the incompatibility of two solvents, such as an oil-based solvent and an aqueous solvent, one being a polar solvent and the other a non-polar solvent. When selecting a solvent, if a polar solvent is used in the previous layer, a non-polar solvent must be used in the next layer, thus satisfying solvent orthogonality. In the process of preparing multiple functional coatings such as carrier layer 12 (electron transport layer and hole transport layer), light-emitting layer, and electrode layer 14 using the electrophoretic deposition apparatus, if the previous coating is an organic material, the solvent used to deposit the current layer must be orthogonal to the solvent used in the previous layer. Solvent orthogonality can avoid the risk of the previous solute being corroded or dissolved off.

[0132] In one embodiment, the photoelectric conversion layer 13 is used to convert light energy into electrical energy based on the transmission of electrons and holes; the photoelectric conversion layer 13 includes an active layer, and the thin-film optoelectronic device 10 includes a photovoltaic cell and a photodetector.

[0133] For example, a photovoltaic cell, also known as a solar photovoltaic cell, solar chip, or photovoltaic cell, can directly convert light energy into electrical energy through the photoelectric effect or photochemical effect. It can be a photoelectric semiconductor thin film that directly generates electricity using sunlight. When sunlight shines on the active layer (AL layer) semiconductor pn junction, new hole-electron pairs are formed. Under the action of the pn junction electric field, holes flow from the n region to the p region, and electrons flow from the p region to the n region. When the circuit is connected, a current is formed.

[0134] Photodetectors can be activated by radiation, which alters the conductivity of the active layer material. Based on the photoelectric effect, thermal detectors, on the other hand, absorb light radiation energy, causing their active layer to heat up and thus changing their electrical properties. Their most significant difference from photon detectors is their lack of wavelength selectivity in light radiation.

[0135] By using electrophoretic deposition to prepare multiple functional coatings such as electrode layer 14, carrier layer 12, and active layer, it is possible to prepare thin-film optoelectronic devices 10 with full structure such as photovoltaic cells and photodetectors, thereby reducing preparation costs, shortening the preparation cycle, and ensuring stable product quality.

[0136] In one embodiment, the carrier layer 12 includes an electron transport layer and a hole transport layer; the electron transport layer and the hole transport layer are prepared by electrophoretic deposition of a suspension, the suspension including a solute and a solvent; the solute of the electron transport layer suspension includes metal nano-oxides; the solute of the hole transport layer suspension includes organic polymers and metal nano-oxides; the solvent includes organic solvents and inorganic solvents.

[0137] For example, the carrier layer 12 of a thin-film optoelectronic device 10, such as a photovoltaic cell or photodetector, may specifically include an electron transport layer and a hole transport layer. The solute and solvent used in the suspension are similar to those used in the preparation of the carrier layer 12 of LEDs and thin-film lasers described above.

[0138] The carrier layer 12 of thin-film optoelectronic devices 10, such as photovoltaic cells and photodetectors, can specifically include an electron transport layer and a hole transport layer. A suspension can be a mixture in which substances distributed in a liquid material are not dissolved but merely dispersed; once the mixture stops oscillating, they precipitate, forming a non-uniform, heterogeneous mixture. The solid particles acting as solutes in a suspension generally have a particle size greater than 1 nm-10 μm, larger than colloids. The liquid material acting as a solvent can be a common organic or inorganic solvent, such as toluene, ethanol, isopropanol, or deionized water.

[0139] The solute used in the suspension of electron transport layers for preparing thin-film optoelectronic devices 10, such as photovoltaic cells and photodetectors, differs from that used in the suspension of hole transport layers. The former can be metal nano-oxides because these materials have high electron mobility; for example, ZnO has an electron mobility of 1*10-3 cm² / VS. The latter can be transparent conductive polymers, organic polymers, and metal nano-oxides. Examples of organic polymers include: poly(3,4-ethylenedioxythiophene) (PEDOT), a mixture of poly(3,4-ethylenedioxythiophene) and polystyrene sulfonate (PEDOT:PSS), poly(4,4-dioctylcyclopentazothiophene); P3HT, doped P3HT (poly(3-hexylthiophene-2,5-diyl)), and poly[N-9”-heptadecyl-2,7-carbazole-alternating-5,5-(4',7'-di-2-thienyl-2',1',3'-benzothiadiazole)] (PCDTBT). Poly[2,6-(4,4-bis(2-ethylhexyl)-4H-cyclopentano[2,1-b;3,4-b']dithiophene)-alternating-4,7(2,1,3-benzothiadiazole)] (PCPDTBT), Poly(N-alkyl dione pyrrolopyrrolodithiophene[3,2-b]thiophene) (DPP-DTT), Methyl [6,6]-phenyl-C61-butyrate (PC60BM), Indene-C60 diadduct (indene-C 60bisadduct (ICBA), spiro-OMeTAD, MoO3, etc.; the metal nano-oxides can be: nickel oxide, nickel magnesium oxide, nickel silver oxide, and other metal-doped nickel oxide nanoparticles, or tungsten oxide, vanadium oxide, and other metal oxide nanoparticles. The suspension of the equipped photovoltaic cells, photodetectors, and other thin-film optoelectronic devices 10 can be stored at a sealed temperature of -5 to +3℃, depending on the properties of the solvent, and shaking should be avoided.

[0140] By using a suspension with specific solutes and solvents to prepare the carrier layer 12 by electrophoretic deposition of the suspension, the electron transport layer and hole transport layer in the full-structure thin-film optoelectronic device 10, such as photovoltaic cells and photodetectors, can be prepared. This reduces the preparation cost, shortens the preparation cycle, and ensures stable product quality.

[0141] Optionally, the solute in the suspension for the electron transport layer of thin-film optoelectronic devices 10, such as photovoltaic cells and photodetectors, can be zinc oxide nanoparticles (ZnO), zinc oxide nanoparticles (ZMO), zinc aluminum oxide nanoparticles (AZO), or other metal nano-oxides. Using metal oxide nanoparticles as the electron transport layer allows for the effective utilization of their high carrier mobility and deep valence band positions. For example, ZnO nanoparticles can be doped with certain ions to form metal-doped nano-oxides. For instance, ZnO nanoparticles can be doped with one of the ions selected from Ga, In, Al, and Mg to form corresponding doped materials, such as ZMO and AZO, thereby further enhancing carrier mobility. By using suspensions of metal nano-oxides such as zinc oxide, zinc oxide nanoparticles, and zinc aluminum oxide nanoparticles as specific solutes, and employing electrophoretic deposition of the suspension to prepare the carrier layer 12, the efficient preparation of the electron transport layer in the full-structure thin-film optoelectronic devices 10, such as photovoltaic cells and photodetectors, can be achieved. This improves the efficiency of electron transfer and transport, which is beneficial for preparing high-performance optoelectronic devices.

[0142] Optionally, the solute in the suspension of the hole transport layer of the thin-film optoelectronic device 10, such as a photovoltaic cell or photodetector, can be polyvinylcarbazole (PVK), neodymium hydroxyquinoline (Ndq), triphenyldiamine (TPD), triphenylamine (TCTA), or other organic polymers. For example, other materials could be N'-bis-(1-naphthyl)-N,N'-biphenyl-1,1'-biphenyl-4,4'-diamine (NPB), poly[(9,9-dioctylfluorene-2,7-diyl)-co-(4,4-(N-(4-sec-butylphenyl)diphenylamine)] (TFB), TPB, etc. These materials have good conductivity, high visible light transmittance, low sheet resistance, strong bonding, and flat surface. By using organic polymers such as polyvinylcarbazole, hydroxyquinoline neodymium, triphenyldiamine, and triphenylamine as specific solutes in a suspension, and preparing the carrier layer 12 by electrophoretic deposition of the suspension, the hole transport layer in the full-structure thin-film optoelectronic device 10, such as photovoltaic cells and photodetectors, can be effectively prepared. This improves the efficiency of electron-hole interaction and is beneficial for preparing high-performance optoelectronic devices.

[0143] Optionally, the suspension solvent for preparing the electron transport layer of thin-film optoelectronic devices 10, such as photovoltaic cells and photodetectors, can be toluene, ethanol, isopropanol, n-hexane, deionized water, or other solvents; the suspension solvent for preparing the hole transport layer can be toluene, ethanol, or various conductive solvents such as chlorobenzene, n-hexane, deionized water, n-octane, 1,4-dioxane, p-Xylene, and o-Xylene. Depending on the different properties of the solvents, suspensions suitable for different sealed storage temperatures can be prepared. By using suspensions with specific solvents such as toluene, ethanol, isopropanol, n-hexane, and deionized water as solvents, and employing electrophoretic deposition of the suspension to prepare the carrier layer 12, the complete fabrication of thin-film optoelectronic devices 10 with full structure, such as photovoltaic cells and photodetectors, can be further realized. Using the same solvent throughout saves raw materials and improves the efficiency of electrophoretic deposition.

[0144] In one embodiment, the electrode layer 14 is prepared by electrophoretic deposition of a suspension, the solute of which includes metal nanoparticles and metal nanowires.

[0145] For example, the solute in the suspension of the electrode layer 14 of the thin-film optoelectronic device 10, such as a photovoltaic cell or photodetector, can be gold, silver, aluminum, copper, or other metals, and can be in the form of nanoparticles or nanowires. The solvent in the suspension of the electrode layer 14 of the thin-film optoelectronic device 10, such as a photovoltaic cell or photodetector, can be ethanol, deionized water, isopropanol, ethanolamine or other conductive solvents, as well as some organic solvents such as toluene and chloroform. Among them, nanoparticles or nanowires are metastable intermediate substances between solids and molecules, and can be "third-state crystalline materials" other than crystalline and amorphous states, possessing unique small-size effects, quantum effects (including macroscopic quantum tunneling effects), surface effects, and interface effects.

[0146] By using a suspension containing metal nanoparticles and metal nanowires as specific solutes, and employing electrophoretic deposition of the suspension to prepare the electrode layer 14, the electrode layer 14 in the full-structure thin-film optoelectronic device 10, such as a photovoltaic cell or photodetector, can be effectively prepared. This reduces preparation costs, shortens the preparation cycle, and is beneficial for preparing high-performance optoelectronic devices.

[0147] In one embodiment, the active layer is prepared by electrophoretic deposition of a suspension, the solute of which includes perovskite materials, semiconductor nanocrystals, and micron-sized materials.

[0148] For example, the solute in the suspension used to prepare the active layer (AL) of thin-film optoelectronic devices such as photovoltaic cells and photodetectors can be a perovskite material; wherein the mixed halide perovskite can be: CH3NH3MX3 or HC(NH2)2MX3, where X contains two or more of F, Cl, Br or I, and CH3NH3MX3 can contain CH3NH3MClxI3-x, CH3NH3MI3-xClx or similar substances. CH3NH3MClxI3-x, CH3NH3MI3-xClx or similar substances can contain non-stoichiometric materials, wherein M is selected from at least one of Pb, Sn, Ge, Si, Ti, Bi or In, and M is preferably Pb.

[0149] Optionally, the perovskite material may comprise a perovskite precursor comprising a solution, the solution of which may comprise one or more perovskite precursor compounds dissolved in a solvent. The perovskite semiconductor forming the active layer may be a metal layer subsequently treated with an organic halide compound, i.e., applying at least one coating of metal M to a substrate to form a substrate, the metal M being selected from at least one of Pb, Sn, Ge, Si, Ti, Bi, or In; and converting the metal coating of the substrate into a perovskite layer by applying at least one perovskite precursor, wherein the perovskite precursor comprises at least one compound having the formula AX, or at least one reactive component for forming at least one compound having the formula AX, wherein A comprises an ammonium group or other nitrogen-containing organic cation and X is selected from at least one of F, Cl, Br, or I.

[0150] The perovskite precursor may comprise molecules crystallized in a perovskite structure. The perovskite precursor preferably comprises at least one compound having the formula AX, or at least one reactive component for forming at least one compound having the formula AX, wherein A comprises an ammonium group or other nitrogen-containing organic cation and X is selected from at least one of F, Cl, Br, or I. The term "perovskite" may refer to a material having a three-dimensional crystal structure associated with CaTiO3 or a material comprising a layer having a structure associated with CaTiO3. The structure of CaTiO3 may be represented by the formula AMX3, wherein A and M are cations of different sizes, and X is an anion. In many embodiments, M comprises a metal cation, and more preferably a divalent metal cation such as Ca²⁺, Sr²⁺, Cd²⁺, Cu²⁺, Ni²⁺, Mn²⁺, Fe²⁺, Co²⁺, Pd²⁺, Ge²⁺, Sn²⁺, Pb²⁺, Sn²⁺, Yb²⁺, and Eu²⁺. In some embodiments, the second cation may be selected from Sn²⁺, Pb²⁺, and Cu²⁺.

[0151] In the unit cell, the A cation is located at (0, 0, 0), the M cation at (1 / 2, 1 / 2, 1 / 2), and the X anion at (1 / 2, 1 / 2, 0). The A cation is typically larger than the M cation. When A, M, and X vary, different ion sizes can cause the structure of the perovskite material to deform from the structure adopted by CaTiO3 to a deformed structure with lower symmetry. If the material contains layers with a structure associated with CaTiO3, the symmetry will be even lower.

[0152] Furthermore, the suspension solute used to prepare the active layer of thin-film optoelectronic devices such as photovoltaic cells and photodetectors can be: a perovskite semiconductor capable of absorbing light and thereby generating free charge carriers; and / or a perovskite semiconductor that emits light by accepting and subsequently recombining charges (both electrons and holes) that emit light. Therefore, the perovskite material used is typically a light-absorbing and / or light-emitting perovskite. The perovskite semiconductor used in this application can be a perovskite that acts as an n-type electron transport semiconductor when light-doped, or it can be a perovskite that acts as a p-type hole transport semiconductor when light-doped. Therefore, the perovskite can be n-type or p-type, or it can be an intrinsic semiconductor. Preferably, the perovskite used can be a perovskite that acts as an n-type electron transport semiconductor when light-doped.

[0153] The solute in the suspension of the active layer for preparing thin-film optoelectronic devices such as photovoltaic cells and photodetectors can also be semiconductor nanocrystals, quantum dots, quantum rods, nanowires, nanosheets, and other nanomaterials or micromaterials. For example, semiconductor nanocrystals can be CdSe, CdS, or core-shell structured CdSe-ZnS, CdSe-CdS quantum dots (one-dimensional nanomaterials) or quantum rods (two-dimensional nanomaterials).

[0154] The solvent for the suspension of the active layer 10 in thin-film optoelectronic devices such as photovoltaic cells and photodetectors can be an organic solvent such as toluene, n-hexane, n-octane, chloroform, tri-n-octylphosphonic acid, or octadecene, or an inorganic solvent, or a mixture of several solvents. The prepared suspension of the active layer 10 in thin-film optoelectronic devices such as photovoltaic cells and photodetectors is sealed and stored in an airtight container.

[0155] Specifically, because the surface of the aforementioned nanocrystals is covered with a large number of organic ligands, such as tetradecyl phosphate and octadecyl phosphate, they must be dissolved in organic solvents such as toluene or n-hexane before preparing the suspension. Then, ethanol or isopropanol (organic solvent: alcohol = 1:2 to 1:5) is added and mixed thoroughly. The mixture is then centrifuged and washed 2-10 times to perform ligand exchange before electrophoretic deposition. The principle and method of ligand exchange is to use organic ligand solutions with shorter carbon chains, such as tri-n-octylphosphine (an acid with 8 carbons) and octanoic acid (8 carbons), to dissolve the active layer material. The solution is shaken until homogeneous and free of agglomerates and flocculent material, and then sonicated for 10-60 minutes. Then, organic solvent and alcohol are added sequentially, following the same method, and the mixture is washed 2-10 times before finally preparing a suspension for use.

[0156] By using a suspension of nanomaterials or micromaterials such as perovskite, semiconductor nanocrystals, and micromaterials as specific solutes, and employing electrophoretic deposition of the suspension to prepare the active layer, the complete fabrication of full-structure thin-film optoelectronic devices 10, such as photovoltaic cells and photodetectors, can be further realized. The process is simple, reduces the preparation cost, shortens the preparation cycle, and is conducive to the preparation of optoelectronic devices with excellent electrical performance.

[0157] Optionally, the concentration of the suspension used to prepare the carrier layer 12, active layer, and electrode layer 14 of the aforementioned thin-film optoelectronic device 10, such as a photovoltaic cell or photodetector, can be 0.1 mg / ml to 300 mg / ml. Suspensions at this concentration exhibit good stability and, under the influence of a DC electric field, allow charged particles in the suspension to move towards the electrode with the opposite polarity, ultimately depositing a dense thin film at the electrode. By using a suspension with a concentration of 0.1 mg / ml to 300 mg / ml and employing electrophoretic deposition of the suspension to prepare the carrier layer 12, active layer, and electrode layer 14, the complete fabrication of the full-structure thin-film optoelectronic device 10, such as a photovoltaic cell or photodetector, can be further achieved. This method is simple, stable, and has a high success rate.

[0158] Optionally, the electrophoretic deposition apparatus for preparing the carrier layer 12, active layer, and electrode layer 14 of the aforementioned thin-film optoelectronic devices 10, such as photovoltaic cells and photodetectors, by electrophoretic deposition of suspension is set with a voltage ranging from 1V to 2000V, a current ranging from 1mA to 10A, and a deposition time ranging from 1s to 3600s. Setting appropriate electrophoretic parameters such as current, voltage, and deposition time helps to provide a suitable electric field force so that charged particles in the suspension are deposited into a dense thin film at the electrodes. By setting the electrophoretic parameters of 1V to 2000V, 1mA to 10A, and 1s to 3600s, the complete fabrication of the carrier layer 12, active layer, and electrode layer 14 using the electrophoretic deposition apparatus can be achieved. This process is simple, versatile, and has a high success rate.

[0159] In one embodiment, the process of preparing a suspension by electrophoretic deposition may specifically include: steps 140, 150, 160, and 170.

[0160] Step 140: Attach the two substrates 11 to the positive and negative electrodes of the electrophoretic deposition apparatus;

[0161] Step 150: Set the deposition parameters of the electrophoretic deposition apparatus and start the electrophoretic deposition apparatus;

[0162] Step 160: Immerse the substrate 11 in the prepared suspension for deposition;

[0163] Step 170: Based on the different properties of the solute in the suspension, attach multiple target layers to the corresponding positive electrode substrate 11 or negative electrode substrate 11.

[0164] The deposition parameters include: sinking rate, pulling rate, deposition time, voltage, and current; the target layers include: electrode layer 14, carrier layer 12, and active layer.

[0165] For example, electrophoretic deposition can be a process in which charged particles in a stable suspension are driven by a direct current electric field to move towards an electrode with the opposite polarity, thus depositing a thin film on the electrode surface. See also... Figure 3 The basic components of the electrophoretic deposition apparatus may include: an electrophoresis tank, a power supply, and a pair of electrode substrates 11, namely, an anode (positive) electrode and a cathode (negative) electrode. The electrophoresis tank can be a quartz glass beaker of a certain volume; the power supply can be a common adjustable DC power supply with a maximum range of 2000V and 10A; the anode and cathode can be Au or Cu sheets, and the distance between the positive and negative electrodes can be freely adjusted; the solvent for the electrophoretic solution can be a 99.8% ethanol solution, or the suspension solvent corresponding to the aforementioned carrier layer 12, active layer, and electrode layer 14, and the solute can be the suspension solute corresponding to the aforementioned carrier layer 12, active layer, and electrode layer 14.

[0166] Optionally, the electrophoretic deposition of the carrier layer 12 (electron transport layer and hole transport layer), active layer and electrode layer 14 is achieved through the following basic processes, thereby realizing the complete fabrication of the full-structure thin-film optoelectronic device 10, such as photovoltaic cell and photodetector.

[0167] For example: (1) Fabrication of the electron transport layer, ETL is deposited on the ITO substrate 11, i.e., the ITO / ETL sample preparation can be as follows:

[0168] Two conductive substrates 11 (ITO glass) are attached to the positive and negative electrodes of the electrophoretic deposition apparatus, respectively. The voltage is adjusted to 1-2000V, the sinking and pulling rates are set to 10-1000mm / min, the deposition time is set to 1-3600s, and the current is set to 1mA-10A. Then, the start button is clicked. The substrate 11 will automatically rotate and immerse itself in the electron transport layer suspension. Under the control of the set voltage, current, and time, the deposition is completed. Then, the substrate 11 will automatically lift off the suspension and return to its original position. The sample is removed from the negative / positive electrode and can be baked at 120℃ for 10min. This completes the preparation of the ITO / ETL sample.

[0169] The final electron transport layer can achieve a controllable thickness ranging from 10nm to 3mm. In principle, ETL material will be deposited on both the positive and negative electrodes. However, due to differences in materials, voltage, current, deposition time, and solution concentration, the deposition quality on the positive and negative electrodes will be inconsistent. The specific deposition sample can be selected according to the actual setting parameters. For quantum dot LEDs, the suspension concentration C = 20mg / ml, the suspension solute can be ZMO, the voltage can be 300V, the current can be 1.2mA, and the deposition time can be 120s. Finally, a dense and uniform ETL coating film will be deposited on the ITO substrate 11 at the positive electrode.

[0170] (2) Preparation of the active layer (AL): Further deposition is performed on the ITO / ETL sample prepared above. That is, the ITO / ETL / AL preparation can be carried out as follows:

[0171] For the nanorod suspension, the ITO / ETL sample prepared in the previous step should first be attached to the negative electrode of the electrophoretic deposition device. For quantum dots or other perovskite materials, the placement on the positive or negative electrode should be determined according to the material properties. Then, a conductive ITO, FTO, or other conductive material substrate 11 is placed on the positive electrode. Next, the deposition parameters are set, and the specific parameters are the same as in (1). The electrophoretic deposition device is started, and the subsequent process is the same as in (1). In particular, before deposition, the active layer suspension should be ultrasonically treated for 10-60 minutes. The final active layer is attached to the negative electrode ITO / ETL sample, and a thickness within a controllable range of 10 nm to 1 mm can be achieved. Optionally, after deposition, the sample is baked at 80-120°C for 15-60 minutes in an oxygen-isolated atmosphere.

[0172] (3) Preparation of the hole transport layer: Further deposition is performed on the prepared ITO / ETL / AL sample, i.e., the preparation of ITO / ETL / AL / HTL can be as follows:

[0173] Since the suspension solute uses NiO nanoparticles, the HTL layer will adhere to the positive electrode. The ITO / ETL / AL sample prepared in the previous step is attached to the positive electrode of the electrophoretic deposition equipment, and a conductive ITO, FTO, or other conductive material substrate 11 is placed on the negative electrode. Set the deposition parameters, the specific parameters are the same as in (1), start the electrophoretic deposition device, and the subsequent process is the same as in (1). In particular, only for inorganic HTL, such as NiO and WO, the HTL suspension needs to be ultrasonically treated for 10-60 minutes before deposition. The final HTL layer is attached to the ITO / ETL / AL sample on the positive electrode. For other materials, the solute should be attached to the positive or negative electrode according to its properties. The thickness can be controlled within the range of 10nm-3mm. Optionally, after deposition, the sample is baked at 80-120℃ for 15-60 minutes.

[0174] (4) Preparation of electrode layer 14: Further deposition is performed on the ITO / ETL / AL / HTL sample prepared above, i.e., the preparation of ITO / ETL / AL / HTL / Electrode can be as follows:

[0175] Since the solute used in the suspension is gold nanoparticles, the Electrode layer will adhere to the positive electrode. The ITO / ETL / AL / HTL sample prepared in the previous step is attached to the positive electrode of the electrophoretic deposition equipment, and a conductive ITO or FTO or other conductive material substrate 11 is placed on the negative electrode. Set the deposition parameters, the specific parameters are the same as in (1), start the electrophoretic deposition device, and the subsequent process is the same as in (1). In particular, before deposition, the Electrode suspension should be ultrasonically treated for 10-60 minutes. The final Electrode layer is attached to the ITO / ETL / AL / HTL sample on the positive electrode. For other materials, the attachment to the positive or negative electrode should be determined according to the properties. The thickness can be achieved within a controllable range of 10nm-3mm. Optionally, after deposition, the sample is baked at 80-150℃ for 15-60 minutes.

[0176] Furthermore, complete optoelectronic devices can be fabricated using only an electrophoretic deposition apparatus, and post-processing can be completed in situ within the electrophoresis tank chamber of the apparatus. Specifically, a heating element is installed in the EPD chamber, which is filled with inert gas for protection. Subsequent layer-by-layer deposition only requires switching between different suspensions to obtain complete devices. No equipment changes or sample transfers are needed, and the entire process takes only 30-60 minutes, which is faster and more reliable than conventional device fabrication methods that typically take at least 4 hours or even several days when different equipment is available.

[0177] It should be noted that: the fabrication process of the carrier layer 12 of the thin-film optoelectronic device 10, such as photovoltaic cells and photodetectors, is similar to the fabrication process of the carrier layer 12 of LEDs and thin-film lasers described above; the fabrication process of the electrode layer 14 of the thin-film optoelectronic device 10, such as photovoltaic cells and photodetectors, is similar to the fabrication process of the electrode layer 14 of LEDs and thin-film lasers described above; and the fabrication process of the active layer of the thin-film optoelectronic device 10, such as photovoltaic cells and photodetectors, is similar to the fabrication process of the light-emitting layer of LEDs and thin-film lasers described above.

[0178] By equipping carrier layer 12 (electron transport layer and hole transport layer), active layer, and electrode layer 14 with suspensions of different solutes, the suspension is deposited using an electrophoretic deposition device, and then multiple functional coatings are deposited at the electrodes. This achieves the complete structure fabrication of photovoltaic cells, photodetectors, and other full-structure thin-film optoelectronic devices 10. The process is simple, reduces the fabrication cost, shortens the fabrication cycle, and is flexible and can be used for large-area fabrication.

[0179] Optionally, during the preparation of the carrier layer 12 (electron transport layer and hole transport layer), active layer, and electrode layer 14 of thin-film optoelectronic devices 10 such as photovoltaic cells and photodetectors using the above-mentioned electrophoretic deposition apparatus, the successfully deposited samples can be baked at a temperature of 20℃-400℃ for 1 min-300 min in an oxygen-isolated atmosphere. Baking can solidify the deposited new thin film layer, making it less prone to detachment and improving the preparation success rate.

[0180] Optionally, solvent orthogonality refers to the incompatibility of two solvents, such as an oil-based solvent and an aqueous solvent, one being a polar solvent and the other a non-polar solvent. When selecting a solvent, if a polar solvent is used in the previous layer, a non-polar solvent must be used in the next layer, thus satisfying solvent orthogonality. In the process of preparing multiple functional coatings such as the carrier layer 12 (electron transport layer and hole transport layer), active layer, and electrode layer 14 of thin-film optoelectronic devices 10 such as photovoltaic cells and photodetectors using the electrophoretic deposition apparatus, if the previous coating is an organic material, the solvent used to deposit the current layer must be orthogonal to the solvent used in the previous layer. Solvent orthogonality can avoid the risk of the previous solute being corroded or dissolved off.

[0181] In one embodiment, the substrate 11 has a preset pattern, and the carrier layer 12, photoelectric conversion layer 13, and electrode layer 14 are deposited by electrophoretic deposition on the preset pattern; wherein, the preset pattern is generated by thin film preparation technology and mask preparation.

[0182] For example, there are many thin film fabrication technologies, such as thermal evaporation, chemical vapor deposition, physical vapor deposition, plasma-enhanced chemical vapor deposition, photolithography, and magnetron sputtering. A photomask, or optical photomask, is a structure that can create and precisely position various functional patterns on thin film, plastic, or glass substrates for selective exposure of photoresist coatings. In the above-mentioned traditional fabrication schemes, a multilayer thin film structure is typically fabricated first, followed by photolithography or etching using a photomask. However, unlike these traditional methods, the thin film optoelectronic device fabrication process provided in this application involves first pre-generating (e.g., etching using a photomask) a corresponding pattern on a substrate, such as an ITO glass substrate; then, multilayer thin films are deposited on this corresponding pattern. Using this method for fabricating thin film optoelectronic devices avoids the tedious operations of subsequent photolithography or etching, and allows the final device pattern to be determined from the initial fabrication stage, enabling precise and rapid fabrication of thin film optoelectronic devices, thus improving the efficiency of thin film optoelectronic device fabrication.

[0183] Optionally, such as Figure 5As shown in the figure, the black area is the ITO glass substrate 11, and the gray area is the generated preset pattern. A mask pattern structure (preset pattern) is formed on the transparent ITO substrate 11 using an opaque light-shielding film, and then the pattern information (preset pattern) is transferred to the product substrate through an exposure process. Various patterns can be generated in the deposition area of ​​the substrate 11 using common thin-film fabrication techniques combined with a mask. Figure 5 The preset pattern is just one example; patterns ranging from 10 nanometers to 5 cm in diameter can be achieved, thus enabling precise control over the deposition area and pattern, and providing scalability.

[0184] In one embodiment, the carrier layer 12 includes: an electron transport layer and a hole transport layer;

[0185] The multilayer thin film stacked structure is formed by electrophoretically depositing a hole transport layer on a substrate 11, electrophoretically depositing a photoelectric conversion layer 13 on the hole transport layer, electrophoretically depositing an electron transport layer on the photoelectric conversion layer 13, and electrophoretically depositing an electrode layer 14 on the electron transport layer.

[0186] And / or, the multilayer thin film stacked structure is formed by electrophoretically depositing an electron transport layer on a substrate 11, electrophoretically depositing a photoelectric conversion layer 13 on the electron transport layer, electrophoretically depositing a hole transport layer on the photoelectric conversion layer 13, and electrophoretically depositing an electrode layer 14 on the hole transport layer.

[0187] For example, following the above preparation sequence of ITO / ETL / EML / HTL / Electrode, the following is obtained: Figure 4 The conventional inverted device structure shown has multiple thin film layers from bottom to top: ITO substrate 11 (Electrode Substrate), ETL layer (electron transport layer), EML layer (light emission layer), HTL layer (hole transport layer), and Electrode layer (electrode layer 14), wherein the carrier layer 12 includes an electron transport layer and a hole transport layer.

[0188] Similarly, the fabrication method provided in this application can also be used to fabricate a positive device with the structure ITO / HTL / EML / ETL / Electrode, that is, the hole transport layer and electron transport layer of the carrier layer 12 are fabricated in reverse order. The multiple thin film layers of this positive device structure from bottom to top are: ITO substrate 11 (Electrode Substrate), HTL layer (hole transport layer), EML layer (light-emitting layer), ETL layer (electrode transport layer), and Electrode layer (electrode layer 14), wherein the carrier layer 12 includes an electron transport layer and a hole transport layer; hybrid structure devices and all-inorganic structure devices can also be further realized, such as: positive all-inorganic structure device, positive hybrid structure device, inverted all-inorganic structure device, and inverted hybrid structure device.

[0189] By adjusting the order of preparing the carrier layer 12, electrode layer 14, and photoelectric conversion layer 13, and by electrophoretically depositing multiple functional coatings in both upright and inverted positions, optoelectronic devices composed of various thin film stacked structures can be realized, providing a broad prospect for the widespread application of these devices in the future.

[0190] In one embodiment, the carrier layer 12 further includes: a hole injection layer, an electron blocking layer, an electron injection layer, and a hole blocking layer; wherein the hole injection layer and the electron injection layer are formed by electrophoretic deposition of a suspension in which metal oxide nanoparticles or polymer materials are immersed as solutes; and the electron blocking layer and the hole blocking layer are formed by dip coating of a suspension in which metal oxide nanoparticles or polymer materials are immersed as solutes.

[0191] For example, in practice, some device materials exhibit band structure mismatch, with significant differences in carrier mobility. This leads to an imbalance between electron and hole injection, potentially causing charging or quenching effects in the photoelectric conversion layer. Therefore, some optoelectronic devices appropriately incorporate injection and blocking layers to balance carrier injection and improve the device's photoelectric efficiency. Furthermore, a device may sometimes have two continuous transport layers (electrons or holes), one of which can be considered the injection layer. Therefore, whether a device requires injection and blocking layers depends on the specific device structure and materials used in its design.

[0192] The solute material in the electron injection layer suspension can be zinc oxide nanoparticles (ZnO), zinc oxide nanoparticles (ZMO), zinc aluminum oxide nanoparticles (AZO), or other metal nano-oxides. It can also be high-molecular-weight organic polymers such as polyvinylcarbazole (PVK) and neodymium hydroxyquinoline (Ndq). These materials possess extremely high electron mobility (e.g., ZnO has an electron mobility of 1*10-3 cm² / VS). Solvents can be deionized water, ethanol, isopropanol, and other organic or inorganic solvents. Weakly conductive solvents, such as toluene, can also be used. The suspension concentration can range from 0.1 mg / ml to 300 mg / ml.

[0193] The solute material in the suspension for hole transport / hole injection can be nickel oxide nanoparticles doped with other metals such as nickel oxide, nickel magnesium oxide, and nickel silver oxide, or tungsten oxide, vanadium oxide, or other metal oxide nanoparticles. It can also be high-molecular-weight organic polymers such as polyvinylcarbazole (PVK) and neodymium hydroxyquinoline (Ndq). Solvents can include ethanol, deionized water, isopropanol, ethanolamine, and other organic or inorganic solvents. Weakly conductive solvents, such as toluene, can also be used. The suspension concentration can range from 0.1 mg / ml to 300 mg / ml. The sealed storage temperature for the suspension is -5 to 3°C, depending on the properties of the solvent.

[0194] The solute material of the hole-blocking layer suspension can be alumina, polyvinylpyrrolidone (PVP) or other polymer materials; the solvent can be ethanol, deionized water, isopropanol, ethanolamine and organic or inorganic solvents such as chlorobenzene, toluene, n-hexane, n-octane, dimethyl sulfoxide or others (determined by the material of the blocking layer).

[0195] The solute material of the electron blocking layer suspension can be alumina, PEI or other insulating polymer materials; the solvent can be ethanol, deionized water, isopropanol, ethanolamine and organic or inorganic solvents such as chlorobenzene, toluene, n-hexane, n-octane, dimethyl sulfoxide or so on (determined by the blocking layer material).

[0196] In the preparation of electron blocking and hole blocking layers, no voltage or current is required. The sample is immersed in a suspension and then slowly extracted. In other words, a uniform and continuous coating with a thickness of 3-6 nm can be obtained directly by dip-coating.

[0197] Specifically, a complete thin-film optoelectronic device 10 can be fabricated with multiple electron transport layers, hole transport layers, and active layers. The device structure can be: electrode layer / carrier injection layer / carrier transport layer / blocking layer / photoelectric conversion layer / (blocking layer) / carrier transport layer / (carrier injection layer) / electrode layer. Among these, a device can consist of multiple layers of carrier transport layers, carrier injection layers, and carrier blocking layers. Whether injection layers and blocking layers are needed depends on the specific device structure and materials designed. Figure 4 A thin-film optoelectronic device 10 with a completely inorganic inverted structure of a transport layer (electrons or holes) is shown; this structure is an idealized omelet device structure. Specifically, as... Figure 6 As shown, this device is a thin-film optoelectronic device 10 that incorporates all possible functional coatings and includes two consecutive transport layers (electrons or holes). The fabrication sequence can be either inverted or upright, primarily determined by the electrode substrate. If the electrode substrate is negative, it is inverted; otherwise, it is upright. The fabrication method can be the electrophoretic deposition process described in steps 100-130 above or the electrophoretic deposition process described in steps 140-170 above.

[0198] For the special carrier layers 12 such as the hole injection layer, electron blocking layer, electron injection layer and hole blocking layer mentioned above, specific solutes and solvents are used as electrophoretic solutions for deposition preparation, which can realize a variety of thin film stacked structure optoelectronic devices containing special functional layers, making carrier injection more balanced and improving the photoelectric efficiency of the device.

[0199] In the embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. The apparatus embodiments described above are merely illustrative. For example, the division of modules is only a logical functional division, and in actual implementation, there may be other division methods. Furthermore, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Additionally, the displayed or discussed mutual couplings, direct couplings, or communication connections may be through some communication interfaces; indirect couplings or communication connections between devices or units may be electrical, mechanical, or other forms. The functional modules in the embodiments of this application can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0200] In this document, relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, without necessarily requiring or implying any such actual relationship or order between these entities or operations.

[0201] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A thin-film optoelectronic device, characterized in that, The thin-film optoelectronic device includes: a substrate, an electrode layer, a carrier layer, and a photoelectric conversion layer; The charge carrier layer is used for the transport of electrons and holes; The photoelectric conversion layer is used to convert light energy into electrical energy based on the transmission of electrons and holes; The electrode layer, carrier layer, and photoelectric conversion layer are formed into a multilayer thin film stacked structure on the substrate by electrophoretic deposition; The photoelectric conversion layer is used to convert electrical energy into light energy based on the transport of electrons and holes; the photoelectric conversion layer includes a light-emitting layer. The carrier layer comprises an electron transport layer and a hole transport layer; the electron transport layer and the hole transport layer are prepared by electrophoretic deposition of a suspension, the suspension comprising a solute and a solvent; the solute of the electron transport layer suspension comprises metal nano-oxide; the solute of the hole transport layer suspension comprises organic polymer and metal nano-oxide; the solvent comprises organic solvent and inorganic solvent. The process for preparing suspensions via electrophoretic deposition includes: Two substrates are attached to the positive and negative electrodes of the electrophoretic deposition apparatus; Set the deposition parameters of the electrophoretic deposition device and start the electrophoretic deposition device; The substrate is immersed in the prepared suspension for deposition; Based on the different properties of the solute in the suspension, multiple target layers are attached to the corresponding positive or negative electrode substrate. The deposition parameters include: sinking rate, pulling rate, deposition time, voltage, and current; the target layer includes: an electrode layer, a carrier layer, and a light-emitting layer. The solvents of the suspensions used in adjacent layers of the plurality of target layers are orthogonal.

2. The thin-film optoelectronic device according to claim 1, characterized in that, in, The metal nano-oxides include: zinc oxide nanoparticles, zinc oxide nanoparticles, and zinc oxide aluminum nanoparticles.

3. The thin-film optoelectronic device according to claim 1, characterized in that, in, The organic polymers include: polyvinylcarbazole, hydroxyquinoline neodymium, triphenyldiamine, and triphenylamine.

4. The thin-film optoelectronic device according to claim 1, characterized in that, in, The organic solvents include toluene, ethanol, isopropanol, and n-hexane; the inorganic solvents include deionized water.

5. The thin-film optoelectronic device according to claim 1, characterized in that, The electrode layer is prepared by electrophoretic deposition of a suspension, the solute of which includes metal nanoparticles and metal nanowires.

6. The thin-film optoelectronic device according to claim 1, characterized in that, The light-emitting layer is prepared by electrophoretic deposition of a suspension, the solute of which includes perovskite materials, semiconductor nanocrystals, and micron-sized materials.

7. The thin-film optoelectronic device according to claim 1, characterized in that, The concentration of the suspension is 0.1 mg / ml to 300 mg / ml.

8. The thin-film optoelectronic device according to claim 1, characterized in that, The voltage for preparing suspensions by electrophoretic deposition is 1V~2000V, the current is 1mA~10A, and the deposition time is 1s~3600s.

9. The thin-film optoelectronic device according to claim 1, characterized in that, The process of preparing the suspension by electrophoretic deposition also includes: baking the target layer attached to the corresponding positive or negative electrode substrate; wherein the baking temperature of the baking treatment is 20℃~400℃; and the baking time of the baking treatment is 1min~300min.

10. The thin-film optoelectronic device according to claim 1, characterized in that, The photoelectric conversion layer is used to convert light energy into electrical energy based on the transmission of electrons and holes; the photoelectric conversion layer includes an active layer, and the thin-film optoelectronic device includes a photovoltaic cell and a photodetector.

11. The thin-film optoelectronic device according to claim 10, characterized in that, in, The charge carrier layer includes an electron transport layer and a hole transport layer; the electron transport layer and the hole transport layer are prepared by electrophoretic deposition of a suspension, the suspension including a solute and a solvent; The suspension solute of the electron transport layer includes metal nano-oxides; The suspension solute of the hole transport layer includes organic polymers and metal nano-oxides; The solvents include organic solvents and inorganic solvents.

12. The thin-film optoelectronic device according to claim 10, characterized in that, in, The electrode layer is prepared by electrophoretic deposition of a suspension, the solute of which includes metal nanoparticles and metal nanowires.

13. The thin-film optoelectronic device according to claim 10, characterized in that, in, The active layer is prepared by electrophoretic deposition of a suspension, the solute of which includes perovskite materials, semiconductor nanocrystals, and micron-sized materials.

14. The thin-film optoelectronic device according to any one of claims 11-13, characterized in that, in, The process for preparing suspensions by electrophoretic deposition includes: Two substrates are attached to the positive and negative electrodes of the electrophoretic deposition apparatus; Set the deposition parameters of the electrophoretic deposition device and start the electrophoretic deposition device; The substrate is immersed in the prepared suspension for deposition; Based on the different properties of the solute in the suspension, multiple target layers are attached to the corresponding positive or negative electrode substrate. The deposition parameters include: sinking rate, pulling rate, deposition time, voltage, and current; the target layer includes: electrode layer, carrier layer, and active layer.

15. The thin-film optoelectronic device according to claim 1, characterized in that, The substrate has a preset pattern, and the carrier layer, photoelectric conversion layer, and electrode layer are deposited by electrophoretic deposition on the preset pattern; wherein, the preset pattern is generated by thin film preparation technology and mask preparation.

16. The thin-film optoelectronic device according to claim 1, characterized in that, The charge carrier layer includes: an electron transport layer and a hole transport layer; The multilayer thin film stacked structure is formed by electrophoretically depositing a hole transport layer on a substrate, electrophoretically depositing a photoelectric conversion layer on the hole transport layer, electrophoretically depositing an electron transport layer on the photoelectric conversion layer, and electrophoretically depositing an electrode layer on the electron transport layer. And / or, the multilayer thin film stacked structure is formed by electrophoretically depositing an electron transport layer on a substrate, electrophoretically depositing a photoelectric conversion layer on the electron transport layer, electrophoretically depositing a hole transport layer on the photoelectric conversion layer, and electrophoretically depositing an electrode layer on the hole transport layer.

17. The thin-film optoelectronic device according to claim 16, characterized in that, The carrier layer further includes: a hole injection layer, an electron blocking layer, an electron injection layer, and a hole blocking layer; The hole injection layer and the electron injection layer are prepared by electrophoretic deposition of a suspension in which metal oxide nanoparticles or polymer materials are immersed as solutes. The electron blocking layer and hole blocking layer are formed by dip coating, in which a suspension of metal oxide nanoparticles or polymer materials as solutes is immersed.

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