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KR-20260067984-A - PEROVSKITE THIN FILM CONTAINING POLYMER THICKENER, MANUFACTURING METHOD THEREOF, AND OPTICAL DEVICE CONTAINING THE SAME

KR20260067984AKR 20260067984 AKR20260067984 AKR 20260067984AKR-20260067984-A

Abstract

The present invention relates to a perovskite thin film containing a polymer thickener, a method for manufacturing the same, and an optical device including the same. The perovskite thin film according to the present invention has a precise pattern on its surface at the nanometer scale, which enables the realization of an optical device having a photonic crystal or a metasurface, and ensures uniform quality by reducing the possibility of process errors due to the wide time window for stamping. Furthermore, the method for manufacturing the perovskite thin film according to the present invention enables nanometer-scale patterning under room temperature and atmospheric pressure conditions, thereby reducing process costs and extending the stamping timing. A wide time window is provided in the nanopatterning process, which significantly improves the stability, ease of use, and reproducibility of the patterning process. Moreover, the optical device according to the present invention includes the perovskite thin film of the present invention to realize metasurfaces and lasing effects based on nanopatterns and can be used as a high-resolution display.

Inventors

  • 이태우
  • 김혜리
  • 장경연

Assignees

  • 서울대학교산학협력단

Dates

Publication Date
20260513
Application Date
20251016
Priority Date
20241106

Claims (16)

  1. As a polycrystalline thin film formed from a perovskite precursor, The above thin film comprises a polymeric thickener with a weight-average molecular weight of 300,000 to 3,000,000 g/mol, and The above polymer thickener delays the crystallization rate of the perovskite, thereby extending the patterning process timing while inducing uniform crystal growth, and A perovskite polycrystalline thin film characterized by having periodic nano-patterns of 10 nm to 100 μm formed on the surface of the thin film.
  2. In claim 1, A perovskite polycrystalline thin film characterized by the inclusion of the above-mentioned polymer thickener in a perovskite precursor solution to delay crystallization and extend the patterning process timing.
  3. In claim 1, A perovskite polycrystalline thin film characterized by securing small process error and uniform quality by widening the stamping-enabled time window.
  4. In claim 1, A perovskite polycrystalline thin film characterized by the weight-average molecular weight of the polymer thickener being 300,000 to 3,000,000 g/mol.
  5. In claim 1, A perovskite polycrystalline thin film characterized by containing the above-mentioned polymer thickener in an amount of 10 to 50 weight percent based on the total weight of the mixture.
  6. In claim 1, A perovskite polycrystalline thin film characterized in that the surface pattern includes a repetitive nano pattern with a size of 10 nm to 100 μm.
  7. In claim 1, A perovskite polycrystalline thin film characterized in that the above perovskite polycrystalline structure includes an ABX3 structure. The above A is a monovalent organic cation, a monovalent inorganic cation, or a combination thereof, and The above B is a divalent metal ion, and The above X is F- , Cl- , Br- , I- , SCN- , OCN- , SeCN- , HCO2- , CH3COO- , or a combination thereof.
  8. In claim 1, A perovskite polycrystalline thin film characterized in that the above-mentioned polymer thickener is one or more selected from the group consisting of polyvinylpyrrolidone (PVP), polyacrylamide (PAAm), polyethylene oxide (PEO), or polyvinyl alcohol (PVA).
  9. A mixture comprising a perovskite precursor and a polymeric thickener having a weight-average molecular weight of 300,000 to 3,000,000 g/mol is prepared, and After forming a perovskite wet film by spin-coating the above mixture, A stamping process is performed within a time range of 85 to 115 seconds before the above wet film is completely crystallized to form a nanometer-scale fine pattern, and A method for manufacturing a perovskite polycrystalline thin film characterized by forming a perovskite polycrystalline thin film by subsequently performing heat treatment.
  10. In claim 9, A method for manufacturing a perovskite polycrystalline thin film characterized by the above-mentioned polymer thickener delaying the crystallization rate to extend the patterning process timing and securing a stamping-capable time window, thereby ensuring uniform quality.
  11. In claim 9, A method for manufacturing a perovskite polycrystalline thin film characterized in that the above-mentioned polymer thickener has a weight-average molecular weight of 300,000 to 3,000,000 g/mol.
  12. In claim 9, A method for manufacturing a perovskite polycrystalline thin film characterized by including the above-mentioned polymer thickener in an amount of 10 to 50 weight% based on the total weight of the mixture.
  13. In claim 9, A method for manufacturing a perovskite polycrystalline thin film characterized by the above manufacturing method being performed under room temperature and atmospheric pressure conditions without high temperature and high pressure conditions.
  14. In claim 9, A method for manufacturing a perovskite polycrystalline thin film characterized in that the stamping process is performed by nanoimprint lithography and polydimethylsiloxane (PDMS) is used as the mold.
  15. In claim 9, A method for manufacturing a perovskite polycrystalline thin film, characterized in that the stamping process is performed by hot plate heat treatment without removing the mold.
  16. An optical device comprising a perovskite polycrystalline thin film according to claim 1 or a perovskite polycrystalline thin film manufactured by the manufacturing method according to claim 9, The optical element is characterized by forming a nano-pattern-based metasurface or photonic crystal structure and being applied to a high-resolution display, meta-optical, or laser element.

Description

Perovskite thin film containing a polymer thickener, manufacturing method thereof, and optical device containing the same The present invention relates to a perovskite thin film containing a polymer thickener, a method for manufacturing the same, and an optical device including the same. More specifically, the invention relates to a perovskite thin film having a nanometer-scale precise pattern on its surface and guaranteed uniform quality, an optical device including the same, and a method for manufacturing a perovskite thin film that reduces processing costs and provides a wide time window in the nanopatterning process. Perovskites are regarded as ideal materials for next-generation displays and optoelectronic devices due to their excellent optical properties, particularly their high luminous efficiency and outstanding color purity. Recently, perovskite-based LED technology has advanced rapidly, with external quantum efficiency approaching theoretical limits; however, driven by advancements in AR/VR displays and metasurface optical devices, a new need for high-resolution perovskite nano-optical devices is emerging. Precise nanopatterning technology at the hundreds of nanometer scale is required for high-resolution optical device applications, and this is essential for realizing complex optical effects. However, nanometer-scale patterning typically requires expensive precision processes such as E-beam lithography or DUV photolithography, resulting in a significant cost burden. In contrast, nanoimprint lithography can significantly reduce process costs by allowing the reuse of polymer replica molds as stamps after the initial patterning process. Generally, forming patterns by directly nanoimprinting perovskite thin films required a process of pressing the film under strong pressure under high temperature and high pressure conditions. However, in this case, the perovskite thin film itself can be deformed, potentially leading to a loss of the desired excellent optical properties. In contrast, a method that can be carried out at room temperature and atmospheric pressure is to perform heat treatment by placing a mold with a pattern engraved on it just before crystallization of the perovskite occurs. Through this method, a precise nanopatterning process is possible at room temperature and atmospheric pressure. However, the traditional stamping process under room temperature and atmospheric pressure conditions had to be carried out with a certain amount of solvent remaining before the perovskite film was completely dried and crystallization was complete; consequently, if the solvent evaporation rate was fast, stamping had to be completed within approximately 20 seconds. This process made precise timing control difficult and prone to process errors, which limited the ability to ensure uniform quality. Meanwhile, in the study ACS Photonics 2022, 9, 3124-3133, a solution containing polyvinylpyrrolidone (PVP) polymer was spin-coated onto a MAPbBr3 perovskite precursor. According to the study, perovskite crystallization is completed in 40 seconds, and since a transition to an intermediate state, which is a pre-crystallization stage, occurs in the preceding 25 seconds, the optimal condition is to perform the stamping at 20 seconds. Although the molecular weight of the PVP polymer used was not specified in the study, it is presumed that low molecular weight PVP was used. On the other hand, when using high molecular weight PVP (e.g., about 1,300,000 g/mol), perovskite crystallization does not occur well even after spin coating for a long time of more than 200 seconds. In addition, the optimal conditions for stamping were significantly delayed to about 100 seconds or more, and as the process time window was also widened, the ease and reproducibility of the process were improved. These effects can be comprehensively applied not only to high molecular weight PVP but also to polymeric thickeners capable of significantly increasing viscosity. Figure 1 is a schematic diagram of the process for manufacturing a perovskite nanoscale pattern using a mixture containing a perovskite precursor and a polymer thickener. Figure 2 is a process diagram for manufacturing a pattern of a perovskite layer. Figure 3 illustrates an example of a material that can be used as a polymer thickener. Figure 4 is a figure showing that when a high-viscosity polymer thickener is used, the stamping timing is delayed compared to the conventional method, and the stamping time window is also expanded compared to the conventional method. Figure 5 is a scanning electron microscope image showing that if stamping is done too quickly outside the stamping time window, cracks occur throughout the film, if stamping is done too slowly, the depth of the pattern is not properly transferred, and if stamping is done within the appropriate time window, a uniform and precise pattern can be formed. Figure 6 is a photograph showing the shape of each pattern transferred to the