Ink-jet printed full-color patterned perovskite QLEDs, preparation method and application
By using a single green perovskite quantum dot ink and inkjet printing in-situ halogen exchange technology, the problem of cumbersome processes in the fabrication of full-color QLEDs has been solved, enabling efficient and low-cost fabrication of full-color patterned QLEDs, suitable for flexible displays and wearable devices.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-18
- Publication Date
- 2026-04-07
AI Technical Summary
Existing inkjet printing technology suffers from long development cycles and low efficiency in the preparation of full-color perovskite QLEDs due to the independent formulation of the three primary color inks and the complicated process optimization. It is difficult to achieve large-area high-precision pixelation and is not suitable for mass production.
By using a single green perovskite quantum dot ink combined with inkjet printing in-situ halogen exchange technology, color emission is adjusted by inkjet printing thin halogen salts on perovskite quantum dots, thus achieving full-color patterning.
The process has been simplified, costs have been reduced, and efficient fabrication of patterned QLEDs covering the full range of red, green, and blue colors has been achieved, making them suitable for flexible displays and wearable devices.
Smart Images
Figure CN121815893A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of quantum dot materials technology, specifically relating to inkjet-printed full-color patterned perovskite QLEDs, their preparation method, and their applications. Background Technology
[0002] Precise deposition of red, green, and blue quantum dot luminescent films is crucial for achieving high-performance full-color displays. Inkjet printing technology, with its unique advantages such as patterning at room temperature, has become one of the most promising large-scale scalable manufacturing technologies. Although inkjet-printed QLEDs still face challenges such as low device efficiency, unstable performance, poor process controllability, and low printing precision, research on inkjet-printed QLEDs remains an important topic.
[0003] Quantum dot materials suitable for red, green, and blue displays can be broadly categorized into three types: cadmium-containing (CdSe) systems, cadmium-free indium phosphide (IPT) systems, and perovskite quantum dot systems. Compared to traditional quantum dots, perovskite quantum dots are considered ideal light-emitting materials for next-generation ultra-high-definition displays due to their low cost, high defect tolerance, simple synthesis methods, and 100% luminescent quantum efficiency. However, limited by spin-coating processes, large-area, high-precision pixelation of QLEDs is currently difficult to achieve, making them unsuitable for large-scale production. Furthermore, previous research on inkjet-printed full-color quantum dots largely relied on developing three primary color quantum dot inks separately, then optimizing and printing these inks to finally fabricate devices. This development process is cumbersome and time-consuming, hindering the fabrication and application of full-color perovskite QLEDs.
[0004] Therefore, how to solve the problems of long development cycle, low efficiency, and difficulty in achieving large-area high-precision pixelation caused by the independent formulation of the three primary color inks and complicated process optimization in the preparation of full-color perovskite QLEDs using existing inkjet printing technology, and how to provide a preparation method that can simultaneously achieve compatible printing of red, green and blue perovskite quantum dot inks, with a unified and efficient process suitable for large-scale production, is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention
[0005] The first objective of this invention is to provide inkjet-printed full-color patterned perovskite QLEDs, addressing the problems in the prior art.
[0006] Therefore, the above-mentioned objectives of the present invention are achieved through the following technical solutions: Full-color patterned perovskite QLEDs printed by inkjet printing include a substrate, a conductive substrate, a hole transport layer, a quantum dot light-emitting layer, an electron transport layer, and a metal electrode. The light-emitting active layer is made of perovskite quantum dot material. A thin layer of halide salt is inkjet printed on the perovskite quantum dots to adjust its color emission, thereby realizing a full-color perovskite quantum dot film.
[0007] While adopting the above technical solutions, the present invention may also adopt or combine the following technical solutions: As a preferred embodiment of the present invention: the chemical structural formula of the perovskite quantum dot is ABX3, and the A site is Cs. + MA + and FA + The B sites are Pb²⁺ and Sn²⁺; the X sites are Cl⁻, Br⁻, and I⁻.
[0008] As a preferred embodiment of the present invention, the surface ligands of the perovskite quantum dots include oleic acid, octane, octylamine, and n-octylamine.
[0009] As a preferred technical solution of the present invention: the chemical formula of the halogen salt is RNH2·HX, the substituent R is a functional group containing -NH2, which refers to an aliphatic group, aryl or aralkyl; the halogen X is Cl, Br, I, and the aliphatic group includes alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, cycloalkynyl, cyclic group, etc.; examples of aryl / aralkyl include benzyl, phenyl, tolyl, xylyl, naphthyl, anthracene, biphenyl, fluorene.
[0010] As a preferred embodiment of the present invention, the halogen salt is soluble in alcohol solvents, including isopropanol, methanol, and ethanol.
[0011] The second objective of this invention is to provide a method for preparing full-color patterned perovskite QLEDs by inkjet printing, addressing the problems in the prior art.
[0012] Therefore, the above-mentioned objectives of the present invention are achieved through the following technical solutions: A method for fabricating full-color patterned perovskite QLEDs by inkjet printing includes the following steps: S1, Printing a hole transport layer on a cleaned patterned substrate and heating it; S2, Print a quantum dot light-emitting layer on the hole transport layer, and use a halogen salt solution to achieve color control and patterning; S3, the light-emitting layer obtained in step S2 is moved into the vacuum chamber, and an electron transport layer and a metal electrode are deposited on it. After completion, QLEDs are obtained.
[0013] The third objective of this invention is to provide an application of inkjet-printed full-color patterned perovskite QLEDs, addressing the problems in the prior art.
[0014] Therefore, the above-mentioned objectives of the present invention are achieved through the following technical solutions: Applications of inkjet-printed full-color patterned perovskite QLEDs include light emission, smart lighting, high-resolution displays, and flexible wearable electronic devices.
[0015] Compared with existing technologies, the inkjet-printed full-color patterned perovskite QLEDs, their preparation method, and applications of this invention have the following beneficial effects: This invention utilizes a single green perovskite quantum dot ink combined with inkjet printing in-situ halogen exchange technology, solving the problems of cumbersome processes, high costs, and difficulty in achieving high-precision patterning caused by the need to separately develop and optimize three primary color inks in the preparation of traditional full-color QLEDs. It achieves efficient preparation of full-color, patterned QLEDs covering red, green, and blue using a single ink, and significantly simplifies the process and reduces costs, providing a feasible technical path for flexible display and wearable device applications.
[0016] The present invention relates to inkjet-printed full-color patterned perovskite QLEDs, their preparation method, and their applications. By designing and developing a high-quality green perovskite quantum ink, inkjet printing is used to perform in-situ anion exchange on the green quantum dot film, thereby controlling the light-emitting position of the quantum dot film. This saves time and raw materials in synthesizing and developing full-color quantum dot inks, thus enabling the preparation of low-cost and high-efficiency inkjet-printed QLEDs devices. Furthermore, by combining them with driving circuits, full-color inkjet-printed display panels can be finally prepared. Attached Figure Description
[0017] Figure 1 This is a flowchart illustrating the fabrication process of a full-color tunable patterned perovskite QLEDs device based on inkjet printing technology, as described in Embodiment 1 of the present invention. Figure 2 This is a schematic diagram illustrating the mechanism of adjusting the color emission of perovskite quantum dots by inkjet printing a thin layer of halide salt on them, as shown in Embodiment 1 of the present invention. Figure 3 Examples 1-3 of the present invention are patterned perovskite quantum dot photoluminescent green films based on inkjet printing; Figure 4 Example 1 of the present invention describes the red, green, and blue full-color films and their corresponding ultraviolet-visible light spectra and photoluminescence spectra obtained by inkjet printing halide salts on green perovskite quantum dot films; Figure 5 XRD patterns of red, green, and blue films were obtained by inkjet printing halide salts on green perovskite quantum dot films, as shown in Example 1 of the present invention. Figure 6 XPS spectra of red, green, and blue films were obtained by inkjet printing halide salts on green perovskite quantum dot films, as described in Example 1 of the present invention. Figure 7 The red, green, and blue light-emitting devices and their corresponding electron emission spectra prepared in Example 1 of the present invention; Figure 8 The image shows the CIE chromaticity diagrams of the red, green, and blue light-emitting devices prepared in Example 1 of this invention. Detailed Implementation
[0018] The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.
[0019] The purpose of this invention is to provide inkjet-printed full-color patterned perovskite QLEDs and their preparation method. Its key feature is that by designing and developing a high-quality green perovskite quantum ink, inkjet printing is used to perform in-situ anion exchange on the green quantum dot film, thereby controlling the light-emitting position of the quantum dot film. This will save time and raw materials in synthesizing and developing full-color quantum dot inks, thus enabling the preparation of low-cost and high-efficiency inkjet-printed QLED devices. Furthermore, by combining these devices with a driving circuit, a full-color inkjet-printed display panel can be ultimately prepared.
[0020] According to one embodiment of the present invention, the chemical structural formula of the luminescent perovskite quantum dot is ABX3, with Cs at the A site. + (cesium ion), MA + (Methylammonium ion) and FA + (Methylammonium ion); B site is Pb²⁺ (lead ion) and Sn²⁺ (tin ion); X site is Cl⁻ (chloride ion), Br⁻ (bromine ion), I⁻ (iodide ion).
[0021] According to one embodiment of the present invention, the substrate includes rigid quartz glass, and also includes flexible substrate materials such as polyvinyl naphthalene, polyimide, polyethylene terephthalate, and polydimethylsiloxane.
[0022] According to one embodiment of the present invention, the conductive electrode is a metal oxide such as indium tin oxide, zinc oxide or tin oxide, and a modification layer for changing the work function of the conductive substrate.
[0023] According to one embodiment of the present invention, the functional transport layer is prepared by solution deposition or vacuum evaporation. For example, the functional transport layer prepared by solution deposition may be poly(3,4-ethylenedioxythiophene / polystyrene sulfonate) (PEDOT:PSS), PEDOT:PSS modified with an ionic electroactive polymer, polyvinylcarbazole (PVK), zinc magnesium oxide, etc. The functional transport layer prepared by vacuum evaporation may be 4,4',4''-tris(carbazole-9-yl)triphenylamine (TCTA), molybdenum oxide or lithium fluoride, 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene (TPBi), or a co-evaporated compound thereof.
[0024] According to one embodiment of the present invention, the metal electrode is a composite electrode of lithium fluoride and aluminum, lithium 8-hydroxyquinoline and aluminum, or cesium carbonate and silver.
[0025] According to another aspect of the present invention, the present invention also provides a method for preparing the above-described full-color tunable patterned perovskite QLEDs based on inkjet printing technology, comprising the following steps: printing a hole transport layer on a cleaned patterned substrate and heating it; subsequently printing a quantum dot emitting layer on the hole transport layer, using a halogen salt solution to achieve color modulation and patterning; moving the quantum dot emitting layer into a vacuum cavity, and evaporating an electron transport layer and a metal electrode thereon, thereby obtaining QLEDs. The application of inkjet-printed full-color patterned perovskite QLEDs is characterized by its applicability to applications such as light emission, smart lighting, high-resolution displays, and flexible wearable electronic devices.
[0026] The present invention has the following beneficial effects: (1) The present invention uses halogen salt solution to in-situ regulate the quantum dot light-emitting layer, which can realize multi-color light emission such as red, green and blue, covering the visible light range and meeting the full color requirements without the need for complex multi-layer structure and material replacement.
[0027] (2) This invention utilizes inkjet printing technology combined with patterned substrates to directly realize the preparation of complex patterns with micron-level resolution, avoiding the cumbersome steps and material waste of traditional photolithography or mask processes, and is suitable for customized display design.
[0028] (3) It adopts printing and vapor deposition processes, is compatible with flexible substrates, and is suitable for flexible electronics and wearable device applications. Example
[0029] The fabrication method of full-color tunable perovskite QLEDs based on inkjet printing technology in this embodiment is as follows: Figure 1 As shown, the specific preparation steps are as follows: Clean the ITO substrate with acetone for 15 minutes, then clean it with isopropanol for 15 minutes by heating, dry it in an oven, and then perform plasma treatment for 15 minutes.
[0030] The cleaned substrate was then deposited with PEDOT:PSS and PVK hole transport layers using inkjet printing and dried at 150 degrees Celsius.
[0031] CsPbBr3 quantum dots were deposited using inkjet printing and then dried in a vacuum at 70 degrees Celsius.
[0032] Green CsPbBr3 films were modified into blue PEACl-CsPbBr3 films and red PEAI-CsPbBr3 films by inkjet printing deposition of PEACl and PEAI, respectively.
[0033] The aforementioned thin film was transferred to a vacuum deposition chamber, where the vacuum level reached 1.0 × 10⁻⁶. -4 Starting below Torr, 30nm TPBi is deposited as an electron transport layer.
[0034] 1 nm of LiF and 100 nm of aluminum were sequentially deposited on the TPBi electron transport layer as the top electrode. Example
[0035] The specific fabrication steps of the full-color tunable perovskite QLEDs device based on inkjet printing technology in this embodiment are as follows: Clean the ITO substrate with acetone for 15 minutes, then clean it with isopropanol for 15 minutes by heating, dry it in an oven, and then perform plasma treatment for 15 minutes.
[0036] The cleaned substrate was then deposited with PEDOT:PSS and PVK hole transport layers using inkjet printing and dried at 150 degrees Celsius.
[0037] CsPbBr3 quantum dots were deposited using inkjet printing and then dried in a vacuum at 70 degrees Celsius.
[0038] Green CsPbBr3 films were modified into blue F-PEACl-CsPbBr3 films and red F-PEAI-CsPbBr3 films by inkjet printing deposition of F-PEACl and F-PEAI, respectively.
[0039] The aforementioned thin film was transferred to a vacuum deposition chamber, where the vacuum level reached 1.0 × 10⁻⁶. -4 Starting below Torr, 30nm TPBi is deposited as an electron transport layer.
[0040] 1 nm of LiF and 100 nm of aluminum were sequentially deposited on the TPBi electron transport layer as the top electrode. Example
[0041] The specific fabrication steps of the flexible full-color tunable perovskite QLEDs device based on inkjet printing technology in this embodiment are as follows: Polyethylene terephthalate (PET / ITO) with a large area of indium tin oxide coating was used as the flexible substrate and electrode. On the aforementioned flexible substrate, PEDOT:PSS and PVK hole transport layers were deposited using inkjet printing and then dried at 150 degrees Celsius.
[0042] CsPbBr3 quantum dots were deposited using inkjet printing and then dried in a vacuum at 70 degrees Celsius.
[0043] Green CsPbBr3 films were modified into blue PEACl-CsPbBr3 films and red PEAI-CsPbBr3 films by inkjet printing deposition of PEACl and PEAI, respectively.
[0044] The above-mentioned thin film was moved to a vacuum evaporation chamber, and 30 nm of TPBi was deposited as an electron transport layer when the vacuum level reached below 1.0 × 10-4 Torr.
[0045] 1 nm of LiF and 100 nm of aluminum were sequentially deposited on the TPBi electron transport layer as the top electrode.
[0046] Results and Discussion Figure 1 This is a flowchart of the fabrication process of a full-color tunable patterned perovskite QLEDs device based on inkjet printing technology in Embodiment 1 of the present invention. From bottom to top, the components are a substrate, a hole transport layer, a light-emitting layer, an electron transport layer, and a top electrode.
[0047] Figure 2 The following is a schematic diagram of the mechanism for adjusting the color emission of perovskite quantum dots by inkjet printing a thin layer of halide salt on the perovskite quantum dots in Embodiment 1 of the present invention. When PEACl is printed on a green CsPbBr3 film, anion exchange Br→Cl occurs, thereby preparing a blue PEACl-CsPbBr3 film. When PEAI is printed on a green CsPbBr3 film, anion exchange Br→I occurs, thereby preparing a red PEAI-CsPbBr3 film.
[0048] Figure 3 Examples 1-3 of this invention are patterned perovskite quantum dot photoluminescent green films based on inkjet printing, such as... Figure 3 It is evident that inkjet printing can print patterned green quantum dot films.
[0049] Figure 4 Example 1 of the present invention describes the red, green, and blue full-color films and their corresponding ultraviolet-visible and photoluminescence spectra obtained by inkjet printing halide salts on green perovskite quantum dot films. Figure 4 It can be seen that printing PEACl can adjust the emission peak of CsPbBr3 film from 516 nm to 418 nm, and printing PEAI can adjust the emission peak of CsPbBr3 film from 516 nm to 625 nm.
[0050] Figure 5In Example 1 of the present invention, XRD patterns of red, green, and blue films of halide salts were obtained by inkjet printing on green perovskite quantum dot films. Compared with CsPbBr3 films, the XRD peaks of PEACl-CsPbBr3 quantum dot films shifted to higher angles, while the XRD peaks of PEAI-CsPbBr3 quantum dot films shifted to lower angles. This indicates that the cell volume has increased or decreased because the radius of I ions is larger than that of Br ions, while the radius of Cl ions is smaller than that of Br ions.
[0051] Figure 6 In Example 1 of the present invention, the XPS spectra of red, green and blue films of halogen salts were obtained by inkjet printing on green perovskite quantum dot films. After PEAX passivation of CsPbBr3 quantum dots, characteristic peaks of I 3d and Cl 2p elements could be observed, which confirmed that the halogen composition of the quantum dots had changed, and it was this change that led to the regulation of the emission color of the quantum dots.
[0052] Figure 7 The red, green, and blue light-emitting devices and their corresponding electron emission spectra prepared in Example 1 of this invention are derived from... Figure 7 As can be seen, the perovskite QLEDs of PEAX-CsPbBr3 quantum dots exhibit bright blue / green / red emission peaks at 485, 517 and 649 nm, respectively.
[0053] Figure 8 The CIE chromaticity diagrams of the red, green, and blue light-emitting devices prepared in Example 1 of the present invention are shown. The color gamut range of the red, green, and blue perovskite QLEDs based on PEAX-CsPbBr3 quantum dots is equivalent to 136% of the sRGB standard and 96% of the NTSC standard.
[0054] The above specific embodiments are used to explain and illustrate the present invention, and are only preferred embodiments of the present invention, not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made to the present invention within the spirit and scope of the claims shall fall within the protection scope of the present invention.
Claims
1. Inkjet-printed full-color patterned perovskite QLEDs, characterized in that, It includes a substrate, a conductive substrate, a hole transport layer, a quantum dot light-emitting layer, an electron transport layer, and a metal electrode. The light-emitting active layer is made of perovskite quantum dot material. A thin layer of halide salt is inkjet printed on the perovskite quantum dots to adjust their color emission, thereby realizing a full-color perovskite quantum dot thin film.
2. The inkjet-printed full-color patterned perovskite QLEDs as described in claim 1, characterized in that, The chemical structural formula of the perovskite quantum dots is ABX3, with Cs at the A site. + MA + and FA + The B sites are Pb²⁺ and Sn²⁺; the X sites are Cl⁻, Br⁻, and I⁻.
3. The inkjet-printed full-color patterned perovskite QLEDs as described in claim 2, characterized in that, Its perovskite quantum dot surface ligands include oleic acid, octane, octylamine, and n-octylamine.
4. The inkjet-printed full-color patterned perovskite QLEDs as described in claim 1, characterized in that, The chemical formula of the halogen salt is RNH2·HX, where the substituent R is a functional group containing -NH2, which refers to an aliphatic group, aryl or aralkyl group; the halogen X is Cl, Br, or I, and the aliphatic group includes alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, cycloalkynyl, and cyclic groups; examples of aryl / aralkyl groups include benzyl, phenyl, tolyl, xylyl, naphthyl, anthracene, biphenyl, and fluorenyl.
5. The inkjet-printed full-color patterned perovskite QLEDs as described in claim 1, characterized in that, Halogen salts are soluble in alcohol solvents, including isopropanol, methanol, and ethanol.
6. A method for preparing full-color patterned perovskite QLEDs by inkjet printing according to any one of claims 1-5, characterized in that, Includes the following steps: S1, Printing a hole transport layer on a cleaned patterned substrate and heating it; S2, a quantum dot light-emitting layer is printed on the hole transport layer, and color control and patterning are achieved using a halogen salt solution; S3, the light-emitting layer obtained in step S2 is moved into the vacuum chamber, and an electron transport layer and a metal electrode are deposited on it. After completion, QLEDs are obtained.
7. The application of the inkjet-printed full-color patterned perovskite QLEDs according to any one of claims 1-5, characterized in that: Applications include light emission, smart lighting, high-resolution displays, and flexible wearable electronic devices.