Method of manufacturing ultra-thin film anti-reflective stickers

Abstract

The present invention relates to a method of manufacturing a single-layered ultra-thin film anti-reflection sticker by a soft etching process, and an ultra-thin film anti-reflection sticker. To this end, the present invention provides a method of manufacturing an ultra-thin film anti-reflection sticker, characterized by comprising: a step of manufacturing a master mold, the master mold being a mold structure in which a plurality of hemispherical shapes are formed on an upper surface; a sticker material coating step of coating a sticker forming material on the upper surface of the master mold; a cured film covering step of covering a cured film on an upper surface of the sticker forming material; a curing step of curing the sticker forming material; a cured film removing step of removing the cured film from the sticker forming material; and a sticker peeling step of peeling the cured sticker forming material from the master mold, and the peeled sticker forming material is formed as a single-layered ultra-thin film anti-reflection sticker in which a plurality of anti-reflection structures are formed on an upper surface.

Description

Technical Field

[0001] This invention relates to a method for manufacturing an ultra-thin film anti-reflective sticker and an ultra-thin film anti-reflective sticker, and further relates to a method for manufacturing an ultra-thin film anti-reflective sticker by a soft-lithography process for manufacturing a single layer of ultra-thin film anti-reflective sticker and an ultra-thin film anti-reflective sticker. Background Technology

[0002] Sticker-type antireflective films are used to improve the efficiency of perovskite solar cells (PSCs) by increasing light transmittance efficiency (LTE).

[0003] Among them, perovskite solar cells (PSCs) have attracted worldwide attention as a promising future energy source due to their excellent characteristics such as high power conversion efficiency (PCE) and ease of manufacturing.

[0004] If a sticker-type anti-reflective film is attached to this perovskite solar cell, excellent light transmission efficiency can be achieved without damaging the perovskite solar cell. Light transmission efficiency is defined as the amount of external light transmitted to the device.

[0005] By effectively transmitting external sunlight to perovskite solar cells, the external quantum efficiency (EQE) of perovskite solar cells increases across the entire wavelength range, which translates to an increase in short-circuit current density (Jsc). Therefore, applying a superior sticker-type anti-reflective film to perovskite solar cells is the most effective and simplest way to improve the power conversion efficiency of solar devices.

[0006] Therefore, sticker-type antireflective films have high light transmission efficiency and are easy to apply to transparent substrates, and are thus being continuously developed along with the commercialization of perovskite solar cells.

[0007] In order to manufacture effective sticker-type anti-reflective films, it is advantageous to choose materials with low refractive index. Therefore, by manufacturing sticker-type anti-reflective films with materials with low refractive index, the anti-reflective effect can be maximized.

[0008] Typically, antireflective coatings are made of polydimethylsiloxane (PDMS) with a refractive index of 1.43, and are used in perovskite solar cells by utilizing the structural optical effects of surface patterning.

[0009] However, the antireflective film made from existing polydimethylsiloxane consists of two layers, thus limiting the minimum thickness that can be manufactured to 200 μm, which makes it difficult to apply to high-efficiency flexible devices.

[0010] [Existing Technical Documents]

[0011] [Patent Document] (Patent Document 1) Korean Patent Publication No. 10-2293742 (Invention Title: Protective Film for Solar Cells and Method for Manufacturing the Same, Publication Date: August 26, 2021) Summary of the Invention

[0012] Technical problems to be solved

[0013] To address the aforementioned problems, the present invention aims to provide a method for manufacturing a single-layer ultra-thin film anti-reflective sticker using a soft etching process, as well as the ultra-thin film anti-reflective sticker itself.

[0014] The technical problems of the present invention are not limited to those described above, and those skilled in the art can clearly understand other technical problems not mentioned from the following description.

[0015] Technical solution

[0016] To address the aforementioned problems, the present invention provides a method for manufacturing an ultra-thin film anti-reflective sticker, characterized by comprising: a step of manufacturing a master mold, wherein a master mold having a plurality of hemispherical mold structures formed on its upper surface is manufactured; a sticker material coating step, wherein a sticker forming material is coated on the upper surface of the master mold; a curing film covering step, wherein a curing film is covered on the upper surface of the sticker forming material; a curing step, wherein the sticker forming material is cured; a curing film removal step, wherein the curing film is removed from the sticker forming material; and a sticker peeling step, wherein the cured sticker forming material is peeled off from the master mold, and the peeled sticker forming material is formed into a single-layer ultra-thin film anti-reflective sticker having a plurality of anti-reflective structures formed on its upper surface.

[0017] In the sticker material coating step, the sticker forming material can be perfluorinated polyether (PFPE).

[0018] Furthermore, in the curing film covering step, the curing film may be made of polyethylene terephthalate (PET).

[0019] In addition, the curing film covering step may include: a covering step, covering the entire area of ​​the upper surface of the sticker forming material with the curing film; and a thickness adjustment step, in which the curing film presses against the sticker forming material to adjust the thickness of the sticker forming material.

[0020] Furthermore, during the sticker peeling step, the anti-reflective structure formed on the upper surface of the ultra-thin anti-reflective sticker can be formed into a hemispherical groove shape.

[0021] Furthermore, the present invention provides an ultra-thin film anti-reflective sticker, characterized in that the ultra-thin film anti-reflective sticker comprises: a base portion formed in a flat plate shape; and a plurality of anti-reflective structures protruding from the upper surface of the base portion and forming hemispherical grooves, wherein the base portion and the anti-reflective structures are integrally formed and are made of the same material.

[0022] Beneficial effects

[0023] The method for manufacturing ultra-thin film anti-reflective stickers and the ultra-thin film anti-reflective stickers according to the present invention have the following effects.

[0024] First, since it is possible to manufacture a single-layer ultra-thin film anti-reflective sticker with multiple anti-reflective structures formed on its upper surface, it has the advantage of being applicable to high-efficiency flexible devices.

[0025] Secondly, since it is formed as a single layer and an ultrathin anti-reflective sticker with a thickness of about 20 μm can be manufactured, the stress applied to the perovskite layer is reduced, thus having the advantage of improving the mechanical stability of flexible perovskite solar cells.

[0026] Third, since the multiple anti-reflective structures formed on the upper surface of the ultra-thin anti-reflective sticker are formed into a moth-eye-shaped conical structure, it has the advantage of improving the anti-reflective effect by utilizing the structural gradient of incident light from air to the substrate.

[0027] Fourth, the ultra-thin anti-reflective sticker of the present invention has the advantage of being able to be attached to the outer surface of various devices such as solar cells without coating a separate adhesive layer or adhesive due to the inherent properties of the perfluoropolyether (PFPE) material and the thin thickness of a single layer. Attached Figure Description

[0028] Figure 1 This is a diagram illustrating the steps of a method for manufacturing an ultra-thin anti-reflective sticker according to the present invention.

[0029] Figure 2 This is a diagram illustrating each step of the method for manufacturing an ultra-thin anti-reflective sticker according to the present invention.

[0030] Figure 3 This is a schematic diagram showing an ultra-thin film anti-reflective sticker according to the invention, manufactured by the method of manufacturing ultra-thin film anti-reflective sticker according to the invention.

[0031] Figure 4 SEM and AFM images of the ultra-thin film anti-reflective sticker according to the invention, manufactured by the method of manufacturing ultra-thin film anti-reflective sticker according to the invention, are shown.

[0032] Figure 5 This is a diagram illustrating the light transmittance and reflectance of the anti-reflective structure of the ultra-thin film anti-reflective sticker according to the invention, manufactured by the method of manufacturing ultra-thin film anti-reflective sticker according to the invention.

[0033] Figures 6 to 9 This is a diagram illustrating the functional characteristics of the ultra-thin film anti-reflective sticker according to the invention, manufactured by the method of manufacturing ultra-thin film anti-reflective sticker according to the invention.

[0034] Figures 10 to 16 This is a diagram illustrating the performance of a perovskite solar cell using an ultrathin antireflective sticker manufactured according to the method of manufacturing ultrathin antireflective stickers according to the present invention.

[0035] Figures 17 to 20 This is a diagram illustrating the stability of the ultra-thin film anti-reflective sticker according to the invention, manufactured by the method of manufacturing ultra-thin film anti-reflective sticker according to the invention.

[0036] Figure 21 This is a diagram illustrating the long-term stability of the ultra-thin film anti-reflective sticker according to the invention, manufactured by the method of manufacturing ultra-thin film anti-reflective stickers according to the invention.

[0037] Explanation of reference numerals in the attached figures

[0038] 100: Base part

[0039] 200: Anti-reflective structure

[0040] 300: Anti-reflective groove

[0041] 1000: Master mold

[0042] 1100: Mold base section

[0043] 1200: Mold structure

[0044] 2000: Sticker Forming Materials

[0045] 2100: Fully cured layer

[0046] 2200: Incompletely cured layer

[0047] 3000: Cured film Detailed Implementation

[0048] The advantages and features of the present invention, as well as the methods of implementing them, will become clear from reference to the accompanying drawings and the detailed description of the embodiments. However, the invention is not limited to the embodiments disclosed below, but can be implemented in various different forms. These embodiments are provided only to fully disclose the invention and to fully illustrate the scope of the invention to those skilled in the art, which is defined only by the scope of the claims. Throughout this specification, the same reference numerals refer to the same constituent elements.

[0049] The terminology used in this specification is for describing particular embodiments and is not intended to limit the invention. As used herein, the singular form may include the plural form unless explicitly stated in the context. Furthermore, throughout this specification, when a part is described as "comprising" or "including" a constituent element, it means that other constituent elements may be further included unless specifically stated to the contrary.

[0050] When describing a component as "connected" or "linked" to another component, it should be understood that a component can be directly connected or linked to another component, but other components may exist in between. On the other hand, when describing a component as "directly connected" or "directly linked" to another component, it should be understood that no other components exist in between. Other expressions used to describe the relationships between components should be interpreted similarly.

[0051] Unless otherwise defined, all terms used in this specification, including technical or scientific terms, shall have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Terms as defined in commonly used dictionaries shall be interpreted as having the meaning consistent with their meaning in the context of the relevant art, and shall not be construed as having an ideal or overly formal meaning unless expressly defined in this specification.

[0052] Figure 1 This is a diagram illustrating the steps of a method for manufacturing an ultra-thin anti-reflective sticker according to the present invention. Figure 2 These are diagrams illustrating each step of a method for manufacturing an ultra-thin anti-reflective sticker according to the present invention. Figure 1 and Figure 2 The method for manufacturing ultra-thin anti-reflective stickers according to the present invention includes the steps of manufacturing a master mold (S100), applying sticker material (S200), covering with a curing film (S300), curing (S400), removing the curing film (S500), peeling off the sticker (S600), and removing the incompletely cured layer (S700).

[0053] In step S100 of manufacturing the master mold, a master mold 1000 is manufactured with a plurality of hemispherical mold structures 1200 formed on its upper surface.

[0054] At this time, the mold structure 1200 is formed into a hemispherical shape protruding from the upper surface of the flat mold base portion 1100. The diameter of the mold structure 1200 can be formed to be 280-320nm, and the height can be formed to be 180-220nm. Specifically, the diameter of the mold structure 1200 is preferably formed to be 300nm, and the height is preferably formed to be 200nm.

[0055] Furthermore, the material of the master mold 1000 is preferably silicon.

[0056] In the sticker material coating step S200, a sticker forming material 2000 is coated on the entire upper surface of the master mold 1000, wherein the sticker forming material 2000 is composed of perfluoropolyether (PFPE).

[0057] In the curing film covering step S300, a curing film 3000 is covered on the upper surface of the sticker forming material 2000 coated on the upper surface of the master mold 1000. Specifically, the curing film covering step S300 includes a covering step and a thickness adjustment step.

[0058] In the covering step, the curing film 3000 covers the entire area of ​​the upper surface of the sticker forming material 2000. The curing film is made of PET, which is a transparent material. Therefore, when the curing step S400 is performed, ultraviolet light (UV) can pass through the curing film and penetrate into the sticker forming material 2000, thereby curing the sticker forming material 2000.

[0059] In the thickness adjustment step, the cured film 3000 presses the sticker forming material 2000 to adjust the thickness of the sticker forming material 2000.

[0060] At this time, in the thickness adjustment step, the cured film 3000 presses the sticker forming material 2000 until the total thickness of the sticker forming material 2000 becomes 20μm, thereby adjusting the thickness of the sticker forming material 2000.

[0061] In the curing step S400, the sticker forming material 2000 is UV cured, wherein, as the curing step S400 proceeds, the sticker forming material 2000 is partially cured, thereby forming a fully cured layer 2100 and an incompletely cured layer 2200.

[0062] In the case of perfluoropolyether as the material of the sticker forming material 2000, if it comes into contact with oxygen during UV curing, the surface that came into contact with oxygen will also be incompletely cured after the UV curing process.

[0063] During the covering step, the entire upper surface of the sticker forming material 2000 is covered by the curing film 3000, but the side areas of the sticker forming material 2000 are exposed to the air, thus the side areas of the sticker forming material 2000 are formed as an incompletely cured layer 2200.

[0064] Specifically, by coating the entire upper surface of the sticker forming material 2000 with the curing film 3000, the sticker forming material 2000 is prevented from contacting the air, and the area covered by the curing film 3000 forms a fully cured layer 2100 in which the sticker forming material 2000 is completely cured.

[0065] Meanwhile, the side areas of the sticker forming material 2000 not covered by the curing film 3000 are exposed to air. In the curing step S400, even if the sticker forming material 2000 is UV cured, it is in contact with oxygen, thus forming an incompletely cured layer 2200 in an incompletely cured state.

[0066] In the cured film removal step S500, the cured film 3000 is removed from the sticker forming material 2000.

[0067] At this time, in the cured film removal step S500, the cured film 3000 is removed from the sticker forming material 2000 based on the adhesive energy between the master mold 1000, the sticker forming material 2000 and the cured film 3000.

[0068] Specifically, the maximum adhesive strength (PFPE-silicon) between the master mold 1000 and the sticker forming material 2000 is 5.526 μJ. This adhesive strength is due to the shape of the area where the master mold 1000 and the sticker forming material 2000 are bonded, i.e., the shape of the mold structure 1200. Furthermore, the maximum adhesive strength (PET-PFPE) between the sticker forming material 2000 and the cured film 3000 is 3.683 μJ. Therefore, the sticker forming material 2000 and the cured film 3000 are preferentially separated.

[0069] Furthermore, in the cured film removal step S500, since the side of the sticker forming material 2000 is formed as an incompletely cured layer 2200, it is easy to preferentially peel off the master mold 1000 and the sticker forming material 2000. When separating from the side of the sticker forming material 2000 and the master mold 1000, it is also easy to peel off the master mold 1000 and the sticker forming material 2000 in the fully cured layer 2100.

[0070] In the sticker peeling step S600, the cured sticker forming material 2000 is peeled off from the master mold 1000. Specifically, the sticker peeling step S600 includes a solvent spraying step and a single-layer sticker forming step.

[0071] In the solvent spraying step, solvent is sprayed onto the side of the sticker forming material 2000. The sprayed solvent penetrates into the space between the master mold 1000 and the side area of ​​the sticker forming material 2000 through capillary action, thereby removing the adhesive force between the master mold 1000 and the side area of ​​the sticker forming material 2000.

[0072] Therefore, the solvent spraying step can prevent forced separation that could occur without removing the adhesive force between the master mold 1000 and the side areas of the sticker forming material 2000, which could lead to tearing and damage of the sticker forming material 2000. The solvent can be acetone.

[0073] In the single-layer sticker forming step, starting from the side area of ​​the master mold 1000 and the sticker forming material 2000 where the adhesive force has been removed, the cured sticker forming material 2000 is peeled off from the master mold 1000. The peeled sticker forming material 2000 is formed into a single-layer ultra-thin film anti-reflective sticker with a plurality of anti-reflective structures 200 formed on its upper surface, and the ultra-thin film anti-reflective sticker will be described in detail later.

[0074] In the incompletely cured layer removal step S700, the incompletely cured layer 2200 and the side areas of the sticker forming material 2000 damaged by solvent in the solvent spraying step, i.e., the side areas of the ultra-thin film anti-reflective sticker, are cut and removed so that the entire area of ​​the ultra-thin film anti-reflective sticker has a uniform anti-reflective effect.

[0075] Figure 3 This is a schematic diagram illustrating an ultra-thin film anti-reflective sticker according to the present invention, manufactured by the method for manufacturing ultra-thin film anti-reflective stickers according to the present invention described above. Figure 4 The images show SEM and AFM images of an ultra-thin film anti-reflective sticker manufactured according to the invention by a method for manufacturing ultra-thin film anti-reflective stickers according to the invention. The ultra-thin film anti-reflective sticker according to the invention includes a substrate 100 and an anti-reflective structure 200.

[0076] The substrate 100 is formed as a flat plate, and the bottom surface of the substrate 100 is attached to products that require anti-reflection, such as perovskite solar cells.

[0077] The anti-reflective structure 200 forms a hemispherical anti-reflective groove 300 protruding from the upper surface of the base portion 100. The anti-reflective groove 300 is composed of multiple grooves and is arranged at predetermined intervals.

[0078] The anti-reflective groove 300 has a diameter (W) of 280-320 nm and a height (D) of 180-220 nm. The anti-reflective groove 300 is formed by the mold structure 1200 described above. The total thickness H of the base portion 100 and the anti-reflective structure 200 is 20 μm.

[0079] At this time, the substrate 100 and the anti-reflective structure 200 are integrally formed as a single layer and are made of the same material, and the material of the substrate 100 and the anti-reflective structure 200 can be cured perfluoropolyether.

[0080] As described above, the upper surface of the ultra-thin anti-reflective sticker according to the present invention forms a plurality of anti-reflective structures 200 and is formed as a single layer, thus it can be applied to high-efficiency flexible devices, and is formed as a thin single layer with a thickness of about 20 μm, thereby improving the mechanical stability of flexible perovskite solar cells due to the reduction of stress applied to the attached perovskite layer.

[0081] Furthermore, the anti-reflective structure 200 forms a moth-eye-shaped conical structure, namely an anti-reflective groove 300, thereby improving the anti-reflective effect by utilizing the structural gradient of incident light from air to the substrate.

[0082] Figure 5 This is a diagram illustrating the light transmittance and reflectance of the anti-reflective structure 200 of the ultra-thin film anti-reflective sticker according to the invention, manufactured by the method of manufacturing ultra-thin film anti-reflective sticker according to the invention.

[0083] Figure 5 (a) shows the light transmittance of a conventional perfluoropolyether film on an FTO glass without the anti-reflective structure 200 formed and the ultra-thin film anti-reflective sticker according to the present invention. It can be confirmed that the ultra-thin film anti-reflective sticker according to the present invention has a higher light transmittance than the conventional perfluoropolyether film.

[0084] also, Figure 5 (b) is a graph showing the thickness and reflectivity of a conventional antireflective film and an ultra-thin antireflective sticker according to the present invention. It can be confirmed that the ultra-thin antireflective sticker according to the present invention is extremely thin and has low reflectivity compared to conventional antireflective films.

[0085] Figures 6 to 9This is a diagram illustrating the functional characteristics of the ultra-thin film anti-reflective sticker according to the invention, manufactured by the method of manufacturing ultra-thin film anti-reflective sticker according to the invention.

[0086] Figure 6 This is a graph showing the light transmittance of the ultra-thin film anti-reflective sticker (UAS) and the comparison film according to the present invention. The comparison film is a common perfluoropolyether film, polydimethylsiloxane (PDMS) with an anti-reflective structure (moth eye) formed, polyurethane acrylate (PUA), or Norland optical adhesive (NOA) film.

[0087] according to Figure 6 The surface refractive index of a conventional perfluoropolyether film changes abruptly at the interface between air and the conventional perfluoropolyether film (n=1 to 1.337), while the ultra-thin film anti-reflective sticker (UAS) according to the present invention gradually increases at the upper end of the nanostructure (height up to 200 nm).

[0088] In particular, the ultra-thin film anti-reflective sticker (UAS) according to the invention uses perfluoropolyether, which has the lowest refractive index among various polymers, thereby effectively showing a gradual change in refractive index. The ultra-thin film anti-reflective sticker (UAS) according to the invention with the smallest rate of change in refractive index has an LTE of 99.97% and shows the best calculated value, thus confirming that it is most effective for improving LTE.

[0089] Figure 7 The diagram illustrates the transmittance and reflectance of an ultra-thin film anti-reflective sticker (UAS) and a comparison film according to the present invention. The comparison film is glass (bare glass), a polydimethylsiloxane (PDMS) film with an anti-reflective structure (moth's eye), and a commercial anti-reflective film.

[0090] according to Figure 7 The average transmittance of commercial antireflective films is 94.85% and the reflectance is 4.20%, while the transmittance of polydimethylsiloxane (PDMS) films is 96.89% and the reflectance is 2.88%. In contrast, the ultra-thin film antireflective sticker (UAS) according to the present invention has a transmittance of 98.43% and a reflectance of 1.43%, exhibiting excellent optical properties. Moreover, compared with the comparative films, it can be confirmed that the curve of optical properties is stable and does not change throughout the wavelength.

[0091] Figure 8 The graph shows the transmittance and reflectance when the ultra-thin anti-reflective sticker (UAS) according to the present invention is applied to indium-tin oxide (ITO) film and FTO glass substrate used as substrates for optical devices.

[0092] according to Figure 8It can be confirmed that the ultra-thin film anti-reflective sticker (UAS) according to the present invention increases the light transmittance by 4.59% and reduces the reflectance by 7.54% in ITO film, and increases the light transmittance by 6.93% and reduces the reflectance by 2.59% in FTO glass.

[0093] Therefore, when the ultra-thin anti-reflective sticker (UAS) according to the present invention is attached to a transparent electrode substrate, the LTE is increased according to the amount of light transmitted to the perovskite solar cell, thereby expecting to increase the effect of increasing the short-circuit current density.

[0094] Figure 9 This diagram illustrates the bending stiffness based on the thickness of perfluoropolyether and polydimethylsiloxane materials. Due to process limitations, the minimum manufacturable thickness of polydimethylsiloxane material is limited to 200 μm, while the thickness of perfluoropolyether material can be manufactured down to 10 μm. However, for stable yield and ease of manufacturing, the thickness of the ultra-thin film anti-reflective sticker (UAS) according to the present invention is manufactured to 20 μm. The bending stiffness of the ultra-thin film anti-reflective sticker (UAS) according to the present invention is 10 nN․ m. Since it can be used as a sticker based on the adhesive force utilizing van der Waals forces, the ultra-thin film anti-reflective sticker (UAS) according to the present invention can be attached to perovskite solar cells without a separate adhesive.

[0095] Figures 10 to 16 This is a diagram illustrating the performance of a perovskite solar cell using an ultrathin antireflective sticker manufactured according to the method of manufacturing ultrathin antireflective stickers according to the present invention.

[0096] Figure 10 and Figure 11 This is a graph showing the current density-voltage (JV) curve and external quantum efficiency (EQE) of a rigid perovskite solar cell.

[0097] like Figure 10 and Figure 11 As shown, the ultra-thin anti-reflective sticker according to the invention, manufactured by the method of manufacturing ultra-thin anti-reflective sticker according to the invention, increases the amount of light reaching the device, thereby improving the performance of the perovskite solar cell.

[0098] In the comparative solar cell device (rigid substrate) described later, a three-dimensional perovskite layer processed by a two-dimensional perovskite method is used as the light-absorbing layer, and the thickness of the light-absorbing layer is confirmed to be 550 nm in the SEM image.

[0099] according to Figure 10 and Figure 11It can be confirmed that in the control solar cell device (rigid substrate), due to the ultra-thin anti-reflective sticker according to the invention manufactured by the method of manufacturing ultra-thin anti-reflective sticker according to the invention, the short-circuit current density increases to 25.51 mA / cm². 2 (Forward scan: 25.53, Reverse scan: 25.48), the average efficiency increased by 1.28% to 24.31 (forward scan: 24.43, reverse scan: 24.18).

[0100] Furthermore, it can be confirmed that the short-circuit current density calculated in the external quantum efficiency is 24.47 mA / cm² in the case of the control solar cell device (rigid substrate). 2 When using an apparatus for an ultra-thin anti-reflective sticker according to the invention, manufactured by the method for manufacturing ultra-thin anti-reflective stickers according to the invention, the voltage is increased to 25.52 mA / cm. 2 The values ​​are similar to those obtained directly from the JV curve.

[0101] That is, the short-circuit current density increases uniformly in the range of 400-800nm, reaching 98.4% at 460nm.

[0102] As a result, it can be confirmed that the increase in short-circuit current density is not due to the basic elements of the device such as the transmissibility of light-absorbing materials, but rather because the ultra-thin anti-reflective sticker according to the present invention, manufactured by the method of manufacturing ultra-thin anti-reflective sticker according to the present invention, suppresses the reflection of light entering from the outside, thereby allowing more photons to reach the perovskite layer.

[0103] Figure 12 This is a graph showing the rate of increase of short-circuit current density (Jsc) of perovskite solar cells under three conditions.

[0104] according to Figure 12 In the case of devices using commercially available antireflective films in the same device group, an average improvement of 0.80 mA / cm was observed. 2 Devices using the ultra-thin anti-reflective sticker manufactured according to the method of manufacturing ultra-thin anti-reflective stickers according to the present invention exhibit an average of 1.12 mA / cm². 2 The improvement in short-circuit current density confirms a higher anti-reflection effect.

[0105] Figure 13 and Figure 14 This is a graph showing the current density-voltage (JV) curve and external quantum efficiency (EQE) of a flexible perovskite solar cell.

[0106] like Figure 13 and Figure 14 As shown, it can be confirmed that the short-circuit current density of the device using the ultra-thin film anti-reflective sticker manufactured according to the method of manufacturing ultra-thin film anti-reflective sticker according to the present invention is 23.04 mA / cm². 2 (Forward scan: 23.04, Reverse scan: 23.06), increase of 1.13 mA / cm 2 Due to the ultra-thin anti-reflective sticker according to the present invention, the average efficiency is also increased from 18.80% (forward scan: 18.80, reverse scan: 18.88) to 20.00% (forward scan: 20.00, reverse scan: 20.01), an increase of 1.2%.

[0107] Furthermore, it can be confirmed that the external quantum efficiency of the device using the ultra-thin anti-reflective sticker according to the present invention increases uniformly in the wavelength range of 350-850 nm.

[0108] Therefore, even if the composition of the three-dimensional perovskite is different, the ultra-thin anti-reflective sticker according to the present invention can allow more light to reach the perovskite layer.

[0109] Figure 15 and Figure 16 This is a graph showing the statistical distribution of the photoelectric performance of rigid and flexible perovskite solar cells using the ultra-thin film anti-reflective sticker according to the present invention, as shown in the figure. Figure 15 and Figure 16 As shown, it can be confirmed that both rigid and flexible perovskite solar cell devices have improved short-circuit current density, thus improving performance.

[0110] Figures 17 to 20 This is a diagram illustrating the stability of the ultra-thin film anti-reflective sticker according to the invention, manufactured by the method of manufacturing ultra-thin film anti-reflective sticker according to the invention.

[0111] Figure 17 This is a graph showing the stability results of the flexible perovskite layer as a result of changes in the neutral plane of the film thickness.

[0112] Typically, a sticker-type anti-reflective film can be applied to increase photon collection. In this case, the distance between the neutral plane and the perovskite layer should be increased, so minimizing the thickness of the anti-reflective film (ultra-thin anti-reflective sticker) is very important.

[0113] At this point, the PFPE film with a thickness of 120 μm has a similar bending stiffness to PDMS with a limited thickness of 200 μm, and due to process limitations, unlike existing antireflective films with a thickness of more than 120 μm, the ultra-thin antireflective sticker according to the present invention can be manufactured with a thin thickness of 20 μm.

[0114] like Figure 17 As shown, it can be confirmed that the ultra-thin film anti-reflective sticker according to the present invention is made of perfluoropolyether (PFPE), but when the ultra-thin film anti-reflective sticker according to the present invention with a thickness of 20 μm is used instead of the 120 μm equivalent that causes less stress in the perovskite layer, the distance between the perovskite layer and the mechanical neutral plane is reduced by 480 nm.

[0115] Figure 18 This is a graph showing the bending test results based on the thickness of the anti-reflective film (ultra-thin anti-reflective sticker) at bending radii of 2mm and 4mm.

[0116] according to Figure 18 It can be confirmed that when the bending test is performed, the ITO electrode is replaced with a conductive polymer (PH1000) with high mechanical durability to better visualize the effect of stress on the perovskite. In the case of a flexible perovskite solar cell with an ultra-thin anti-reflective sticker according to the present invention, the initial efficiency is maintained even after 10,000 bending tests at a bending radius of 2 mm.

[0117] On the other hand, it can be confirmed that with an ultra-thin anti-reflective sticker having a thickness of 120 μm, the efficiency is reduced to 52% of the initial efficiency under the same conditions.

[0118] In fact, after 10,000 bending tests within a 2mm radius of curvature, the shape of the perovskite film of the device using the 20μm ultrathin antireflective sticker according to the present invention remained almost unchanged. However, when using an ultrathin antireflective sticker with a thickness of 120μm, cracks were confirmed to occur (see reference). Figure 17 ).

[0119] Therefore, the ultrathin anti-reflective sticker of the present invention, which is formed as thin as 20 μm, not only improves the efficiency of flexible perovskite solar cells, but also minimizes the negative impact on mechanical durability that inevitably occurs when using existing anti-reflective stickers.

[0120] Figure 19 This is a graph showing the stability test results of the ultra-thin film anti-reflective sticker in extreme external environments. Figure 20 This is a graph showing the optical stability results of the film applied to perovskite solar cells after 1000 hours of damp heat testing at 85°C / 85%.

[0121] according to Figure 19 and Figure 20 The ultra-thin film anti-reflective sticker according to the present invention was placed in various environments for 168 hours under atmospheric, water, strong light (2250 lm), high temperature (85°C), and 85°C / 85% relative humidity (85 / 85 damp heat test) conditions to conduct a stability test. After the above tests, the optical durability of the ultra-thin film anti-reflective sticker according to the present invention maintained its transmittance and reflectance, and this could be confirmed by comparison with the ultra-thin film anti-reflective sticker according to the present invention measured immediately after manufacturing.

[0122] In addition, for application in solar cells, such as Figure 20 As shown, when the ultra-thin film anti-reflective sticker according to the invention is used after being exposed to 85°C / 85% damp heat for 1000 hours under these test conditions, it can be confirmed that it exhibits performance almost similar to that of the ultra-thin film anti-reflective sticker according to the invention measured immediately after manufacturing.

[0123] Therefore, the ultra-thin anti-reflective sticker according to the present invention can maintain the high efficiency of perovskite solar cells for a long time even in harsh external environments.

[0124] Figure 21 This is a diagram illustrating the long-term stability of the ultra-thin film anti-reflective sticker according to the invention, manufactured by the method of manufacturing ultra-thin film anti-reflective sticker according to the invention. It can be confirmed that the transmittance and reflectance remain at similar levels in the cases of the ultra-thin film anti-reflective sticker according to the invention that was just manufactured and the ultra-thin film anti-reflective sticker according to the invention after 6 months of manufacture.

[0125] As described above, preferred embodiments of the present invention have been illustrated and explained with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. Various modifications can be made by those skilled in the art without departing from the spirit of the invention as claimed in the claims, and such modifications should not be understood solely from the technical concept or perspective of the present invention.

Claims

1. A method for manufacturing an ultra-thin anti-reflective sticker, characterized in that, include: The steps of manufacturing the master mold are to manufacture a master mold with multiple hemispherical mold structures formed on its upper surface; The sticker material coating step involves coating the upper surface of the master mold with a sticker forming material; The curing film covering step involves covering the upper surface of the sticker forming material with a curing film. The curing step involves curing the sticker forming material. The cured film removal step removes the cured film from the sticker forming material; as well as In the sticker peeling step, the cured sticker forming material is peeled off from the master mold, and the peeled sticker forming material forms a single-layer ultra-thin anti-reflective sticker with multiple anti-reflective structures formed on its upper surface. In the curing step, the sticker forming material generates a fully cured layer that is completely cured by being covered by the curing film, and an incompletely cured layer that is not fully cured by the side areas not covered by the curing film when exposed to air. The sticker peeling step includes a solvent spraying step, in which solvent is sprayed onto the side areas of the sticker forming material where the incompletely cured layer has formed. The solvent, penetrating into the space between the master mold and the side areas of the sticker forming material, removes the adhesive force between the master mold and the side areas of the sticker forming material. Following the sticker peeling step, a further step is included: an incompletely cured layer removal step, which cuts and removes the incompletely cured layer present in the side areas of the sticker forming material and the areas damaged by the solvent.

2. The method for manufacturing ultra-thin anti-reflective stickers according to claim 1, characterized in that, In the sticker material coating step, the sticker forming material is perfluoropolyether (PFPE).

3. The method for manufacturing ultra-thin anti-reflective stickers according to claim 1, characterized in that, In the curing film covering step, the curing film is made of polyethylene terephthalate (PET).

4. The method for manufacturing ultra-thin anti-reflective stickers according to claim 1, characterized in that, The curing film covering step includes: The covering step involves covering the entire surface of the upper surface of the sticker forming material with the cured film; and In the thickness adjustment step, the cured film is pressed against the sticker forming material to adjust the thickness of the sticker forming material.

5. The method for manufacturing ultra-thin anti-reflective stickers according to claim 1, characterized in that, During the sticker peeling step, the anti-reflective structure formed on the upper surface of the ultra-thin anti-reflective sticker forms a hemispherical groove shape.

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