KR102749092B1 - Antireflective coating polymeric film for photoelectric device and photoelectric device comprising the same - Google Patents

Abstract

The present disclosure relates to a polymer antireflection film for a photovoltaic device and a method for manufacturing the same. More specifically, the polymer antireflection film includes a transparent polymer; and micro fluorescent particles and nano oxide particles; and may include a textured surface having a three-dimensional structure on at least one surface.

Description

{ANTIREFLECTIVE COATING POLYMERIC FILM FOR PHOTOELECTRIC DEVICE AND PHOTOELECTRIC DEVICE COMPRISING THE SAME}

According to embodiments of the present disclosure, the present invention relates to a polymer antireflection film for a photovoltaic device and a photovoltaic device including the same.

1 및 n_perovskite

2.5)로 인해 공기-페로브스카이트 셀 경계면의 반사로 인해 입사광의 약 18.4%가 손실된다. Multi-junction solar cells can achieve power conversion efficiencies (PCEs) that surpass those of single-junction solar cells. Among various multi-junction solar cells, perovskite/silicon (Si) tandem solar cells have commercial potential due to their economic advantages. In perovskite/Si tandem solar cells, the effective optical path design of the tandem cell is a critical factor. The optical design is to minimize the reflection loss of light in the visible range and reduce parasitic absorption of light especially in the UV range. Typically, when light is incident on the top perovskite cell of a tandem structure, the difference in refractive index (e.g., n _air)

1 and n _perovskite

2.5) About 18.4% of the incident light is lost due to reflection at the air-perovskite cell interface.

1.39) 필름을 종종 TCO(top transparent conductive oxide) 상단에 배치한다. 텍스처화된 PDMS 필름의 문제는 다중 내부 산란만 이용하고 PDMS의 굴절률이 공기와 TCO 사이에 있지 않다는 것이다. 또한, 표면 반사율 손실 외에도 300 nm ~ 1200 nm 파장 범위의 기생 흡수는 탠덤 셀에서 발생한다. 특히, TCO와 버퍼층에 의한 단파장 광(λ< 500 nm)의 기생 흡수는 페로브스카이트 층의 UV 광 흡수를 크게 제한하여 직렬 소자의 PCE를 낮출 수 있다.To reduce surface reflection, a polymeric antireflection coating, i.e., textured poly(dimethylsiloxane) (PDMS) (n _PDMS)

1.39) The film is often placed on top of a top transparent conductive oxide (TCO). The problem with textured PDMS films is that they only utilize multiple internal scattering and the refractive index of PDMS is not between that of air and TCO. In addition, in addition to the surface reflectivity loss, parasitic absorption in the wavelength range of 300 nm to 1200 nm occurs in tandem cells. In particular, parasitic absorption of short-wavelength light (λ<500 nm) by the TCO and buffer layers can significantly limit the UV light absorption of the perovskite layer, which can lower the PCE of the tandem device.

Alternative transparent electrodes such as graphene and reduced graphene oxide have been proposed to increase the transmittance in the UV region, but they do not completely solve the problem. In addition, when UV light is transmitted into the perovskite layer, high-energy UV photons can accelerate the dissociation of the perovskite layer into PbI ₂ and by-products, resulting in rapid degradation in the PCE.

To solve the above-mentioned problems, the present disclosure may relate to optical design for improving PCE in photovoltaic devices and enhancing device stability under UV illumination.

According to one embodiment, the present disclosure provides a polymer anti-reflection film that can improve UV light stability in a photovoltaic device and further maximize the anti-reflection effect to minimize light loss through an optical design utilizing a photo-operational design and a mis-scattering mechanism using a fluorescent substance and nano-oxide particles.

According to one embodiment, the present disclosure provides a photovoltaic device having improved optical performance and efficiency (e.g., power conversion efficiency) by applying a polymer antireflection film according to embodiments of the present disclosure.

However, the problems to be solved by the present invention are not limited to those mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

A polymer antireflection film according to embodiments of the present disclosure may include a transparent polymer; and micro fluorescent particles and nano oxide particles; and may include a textured surface having a three-dimensional structure on at least one surface.

According to one embodiment, the transparent polymer may include at least one or more of polydimethylsiloxane (PDMS), polydiphenylsiloxane (PDPhS), polymethylphenylsiloxane (PMPS), ethylene-vinyl acetate copolymer (EVA), poly olefin elastomer (POE), polymethyl metacrylate (PMMA), triacetate cellulose (TAC), polyethylene terephthalate (PET), poly(ether ketone) (PEK), polymer glass, polycarbonate (PC), and polyolefin, or a combination thereof.

According to one embodiment, the three-dimensional structure may be arranged regularly or irregularly, and the three-dimensional structure may include at least one or more of a sphere, an ellipse, a cone, a polypyramid, a polyprism, a polygon, and a polyhedron, or a combination thereof.

According to one embodiment, at least one surface of the polymer anti-reflection film may include a protrusion, a recess, or both having a three-dimensional structure.

According to one embodiment, the height of the protrusion and the depth of the recess may each be from about 1 um (micrometer) to about 10 um (micrometer).

According to one embodiment, the micro fluorescent particles and the nano oxide particles may be present in an amount of about 0 wt % (exceeding) to 6 wt % of the polymer anti-reflection film.

According to one embodiment, the mass ratio of the micro fluorescent particles to the nano oxide particles may be from about 1: about 10 to about 1: about 1.

According to one embodiment, the size of the micro fluorescent particles may be from about 1 um (micrometer) to about 5 um (micrometer).

According to one embodiment, the micro fluorescent particles may include at least one of a red fluorescent substance, a green fluorescent substance and a blue fluorescent substance; or a combination thereof.

According to one embodiment, the micro phosphor particles may include at least one or more of a silicon-based phosphor, a nitride-based phosphor, and an oxide-based phosphor, or a combination thereof.

According to one embodiment, the phosphor may include at least one of a red phosphor, a green phosphor, and a blue phosphor; or a combination thereof.

According to one embodiment, the size of the nano oxide particles may be from about 30 nm (nanometers) to about 400 nm (nanometers).

According to one embodiment, the nano-oxide particles include oxide particles having a light-scattering function, and the nano-oxide particles may include light-scattering particles including at least one or more of silica, titanium oxide, magnesium oxide, barium oxide, aluminum oxide, bismuth oxide, zirconium oxide, tin oxide, tungsten oxide, strontium oxide, niobium oxide, zirconium oxide, and zinc oxide, or a combination thereof.

According to one embodiment, the light transmittance of the polymer anti-reflection film may be 90% or greater.

According to one embodiment, the thickness of the polymer anti-reflection film may be from about 50 um (micrometers) to about 300 um (micrometers).

The photovoltaic device according to embodiments of the present disclosure may include a polymer anti-reflection film according to embodiments of the present disclosure. The polymer anti-reflection film is as described above.

In one embodiment, the photovoltaic device may include a perovskite solar cell, a silicon solar cell, or both.

According to one embodiment, the photovoltaic device may include a monolithic perovskite solar cell layer; and a silicon tandem solar cell layer; and may include a polymer antireflection film on the monolithic perovskite solar cell layer.

According to one embodiment, the present disclosure provides a polymer anti-reflection film that can improve UV light stability in a photovoltaic device and further maximize anti-reflection effect to minimize light loss.

According to one embodiment, the present disclosure provides a photovoltaic device having improved optical performance and efficiency (e.g., power conversion efficiency) by applying an anti-reflection film according to embodiments of the present disclosure.

In one embodiment, FIG. 1a is a schematic diagram of a polymeric anti-reflective film (ARC film) (e.g., a PDMS layer) including a phosphor (e.g., a SGA phosphor) and oxide nanoparticles (e.g., SiO ₂ nanoparticles). FIG. 1b is an image of the polymeric anti-reflective film (e.g., a PDMS layer) including a phosphor (e.g., a SGA phosphor) and oxide nanoparticles (e.g., SiO ₂ nanoparticles) under ambient light and UV light (λ = 365 nm). FIG. 1c is a schematic diagram of a perovskite/Si tandem solar cell with a PDMS layer including a SGA phosphor and SiO ₂ nanoparticles. FIG. 1d is a cross-sectional SEM image of the perovskite-Si solar cell.
According to one embodiment, FIG. 2a is the excitation (λ _ex : 380 nm) and emission (λ _em : 530 nm) of the SGA phosphor (inset: SEM image of the SGA phosphor), FIG. 2b is the total transmittance, FIG. 2c is the diffuse transmittance, and FIG. 2d is the reflectance of the ARC film on glass as a function of the volume % of the SGA phosphor. FIG. 2e is the JV of a tandem solar cell using the same film, and FIG. 2e is the IPCE curve.
In one embodiment, FIG. 3a is a SEM image of SiO ₂ nanoparticles, FIG. 3b is total transmittance, and FIG. 3c is diffuse transmittance. FIG. 3d is reflectance of textured ARC_S (0.8) on glass and textured ARC film on glass and glass. FIG. 3e is J-V curve of tandem solar cell without the same film and FIG. 3f is IPCE curve.
In one embodiment, FIG. 4a is a schematic diagram of the FDTD simulation setup for a single particle (SiO ₂ @Air) scattering model and a multiple scattering model. For the single scattering model, 100 nm sized SiO ₂ particles with a 10 nm air gap (SiO ₂ @Air) are added as scatterers in the PDMS matrix (0.8 vol.%). For the multiple scattering model, 729 SiO ₂ @Air particles are randomly distributed in the PDMS with the same vol.%. The refractive indices of PDMS and SiO ₂ are 1.39 and 1.46 at 623 nm, respectively. FIG. 4b is the normalized scattering cross-sections for PDMS only, single scattering of SiO ₂ @Air, and multiple scattering of the SiO2@Air system. Figure 4c is the estimated specular transmittance for a 150 μm thick film based on the scattering cross-section results (but the air/PDMS and PDMS/substrate interface conditions are not considered).
In one embodiment, FIG. 5a is the total transmittance and FIG. 5b is the diffuse transmittance of ARC_S(0.8) with different volume % (0.4, 0.8, 1.2, 1.6 %) of SGA phosphors (ARC_S(0.8), ARC_S(0.8)SGA(0.4), ARC_S(0.8)SGA(0.8), ARC_S(0.8)SGA(1.2), and ARC_S(0.8)SGA(1.6)). FIG. 5c is the J-V curve of the tandem solar cell without or with an antireflection coating of SGA and SiO ₂ nanoparticles, and FIG. 5d is the IPCE. FIG. 5e is the expanded IPCE spectrum below 450 nm of the tandem solar cell with ARC_S(0.8)SGA(0.8), and FIG. 5f is the hysteresis.
According to one embodiment, FIG. 6a shows the absorption rate and integrated current density of PC61BM/ZnO/IZO within the wavelength range of 300 nm to 450 nm.
As an example, _FIG . 6b shows the normalized PCE of perovskite (Au/Sprio-OMeTAD/Perovskite/TiO2/FTO) with and without ARC and phosphor-embedded ARC under continuous UV (365 nm) exposure (15 W/ ^cm2 ) in N2.

Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings. In describing the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the gist of the present invention, the detailed description will be omitted. In addition, the terms used in this specification are terms used to appropriately express the preferred embodiments of the present invention, and this may vary depending on the intention of the user or operator, or the customs of the field to which the present invention belongs. Therefore, the definitions of these terms should be made based on the contents throughout this specification. The same reference numerals presented in each drawing represent the same members.

Throughout the specification, when it is said that an element is "on" another element, this includes not only cases where the element is in contact with the other element, but also cases where there is another element between the two elements.

Throughout the specification, when it is said that a part "includes" a component, this does not mean that it excludes other components, but rather that it may include other components.

Hereinafter, the polymer antireflection film of the present disclosure and the photoelectric device including the same will be specifically described with reference to examples and drawings. However, the present invention is not limited to these examples and drawings.

In one embodiment, the polymeric anti-reflective coating may include a transparent polymer; and a fluorescent substance and nano-oxide particles. In one embodiment, the polymeric anti-reflective coating may include a textured surface over at least a portion or substantially the entirety of at least one surface.

1.9)로 인해 고분자 반사방지막의 반사율을 증가시킬 수 있다. 또한, 이러한 형광체에 의한 후방 산란 문제(backward scattering problem)는 나노 산화물(예: SiO₂) 입자(예: 구형)를 추가함으로써 보완될 수 있다. 즉, 고분자 반사방지막의 나노 산화물(예: SiO₂) 입자가 확산 투과율을 증가시켜 반사율을 감소시킬 수 있다. 이러한 광학 설계에 따른 고분자 반사방지막은 광전소자(예: 페로브스카이트/실리콘 탠덤 태양 전지)의 광 흡수를 성공적으로 촉진하고, 탠덤 전지의 광학 성능 및 효율(예: 전력 변환 효율)을 향상시킬 수 있다. In one embodiment, the polymeric anti-reflective coating relates to an optical design that combines the optical properties of the textured polymeric anti-reflective coating with the down-conversion effect of the phosphor particles and the multiple scattering effect of the nano-oxide (e.g., SiO ₂ ) particles. That is, the phosphor can be introduced to convert the UV light into visible light to address the parasitic absorption of the UV light. Furthermore, the micro-size (e.g., > about 5 μm) and high refractive index (e.g., n ) of the phosphor embedded in the polymeric anti-reflective coating

1.9) can increase the reflectance of the polymer anti-reflection coating. In addition, the backward scattering problem by such a phosphor can be supplemented by adding nano-oxide (e.g., SiO ₂ ) particles (e.g., spherical). That is, the nano-oxide (e.g., SiO ₂ ) particles of the polymer anti-reflection coating can increase the diffuse transmittance, thereby reducing the reflectance. The polymer anti-reflection coating according to such an optical design can successfully promote light absorption of photovoltaic devices (e.g., perovskite/silicon tandem solar cells) and improve the optical performance and efficiency (e.g., power conversion efficiency) of the tandem cell.

According to one embodiment, the transparent polymer forms a base matrix of a polymer anti-reflection film, and any polymer applicable to a film for a polymer anti-reflection film for a photovoltaic device can be applied without limitation. In some examples, the transparent polymer can be a thermosetting or photocurable polymer. In some examples, PDMS (polydimethylsiloxane), PDPhS (polydiphenylsiloxane), PMPS (polymethylphenylsiloxane), EVA (ethylene-vinyl acetate copolymer), POE (poly olefin elastomer), PMMA (polymethyl metacrylate), TAC (triacetate cellulose), PET (polyethylene terephthalate), PEK (poly(ether ketone), polymer glass, polycarbonate (PC), polyolefin (e.g., polyethylene (PE), polypropylene (PP), etc.), cyclic olefin copolymer (COC), ethylene vinyl acetate, polyvinyl chloride (PVC), polyamide (PA), polyurethane, polymethylmethacrylate (PMMA), polyarylate, It may include at least one or more of polyvinyl acetate, polyethylene phthalate, polyimide (PI), polyethylene terephthalate (PET), polyethersulfone (PES), and polybutylene terephthalate, or a combination thereof. In some examples, it may be selected from polydimethylsiloxane (PDMS), polydiphenylsiloxane (PDPhS), polymethylphenylsiloxane (PMPS), ethylene-vinyl acetate copolymer (EVA), poly olefin elastomer (POE), polymethyl metacrylate (PMMA), and triacetate cellulose (TAC), and polyethylene terephthalate (PET).

In one embodiment, the textured surface of the polymer anti-reflection film may be a geometrically three-dimensionally textured surface by a three-dimensional structure. In one embodiment, the three-dimensional structure may be arranged regularly or irregularly. In some examples, the three-dimensional structure may include at least one or more of a sphere, an ellipse, a cone, a polypyramid (e.g., a triangular pyramid, a square pyramid, a pentagonal pyramid, a hexagonal pyramid, etc.), a polyprism (e.g., a triangular prism, a square prism, a pentagonal prism, a hexagonal prism, a hexagonal prism), a cylinder, an elliptical structure, a polygon (e.g., an n-gon, where n is an integer greater than or equal to 3), and a polypyramid (e.g., a pentagonal star, a hexagonal star, a heptagonal wall, an octagonal star, etc.), or a combination thereof. In one embodiment, the three-dimensionally textured surface may include a protrusion, a recess, or both. In some examples, the protrusion may be related to the three-dimensional structure mentioned above. In some examples, the recess can be a groove having the three-dimensional structure shape (or, cross-section) mentioned above. The bottom surface of the recess can be a round or pointed tip (e.g., v-shaped). In some examples, the height of the protrusion (e.g., the height of the three-dimensional structure) and the depth of the recess can be about 1 um (micrometer) to about 10 um (micrometer); about 2 um (micrometer) to about 10 um (micrometer); about 3 um (micrometer) to about 10 um (micrometer); about 5 um (micrometer) to about 10 um (micrometer); about 2 um (micrometer) to about 8 um (micrometer); about 2 um (micrometer) to about 6 um (micrometer); or preferably about 2 um (micrometer) to about 5 um (micrometer), respectively. In some examples, the diameter (or length) of the protrusion and the diameter (or length) of the recess can be from about 1 um (micrometer) to about 10 um (micrometer); from about 2 um (micrometer) to about 10 um (micrometer); from about 3 um (micrometer) to about 10 um (micrometer); from about 5 um (micrometer) to about 10 um (micrometer); from about 2 um (micrometer) to about 8 um (micrometer); from about 2 um (micrometer) to about 6 um (micrometer); or preferably from about 2 um (micrometer) to about 5 um (micrometer). Being within the ranges mentioned in some examples can reduce surface reflection.

In one embodiment, the phosphor and nano-oxide particles can be present in the polymer anti-reflective coating in an amount of from about 0 wt % (exceeding) to about 6 wt %; from about 0 wt % (exceeding) to about 5 wt %; from about 0 wt % (exceeding) to about 4 wt %; from about 0 wt % (exceeding) to about 3 wt %; from about 0 wt % (exceeding) to about 2 wt %; from about 0 wt % (exceeding) to about 1.5 wt %; from about 0 wt % (exceeding) to about 1 wt %; from about 0.5 wt % to about 4 wt %; or from about 0.5 wt % to about 3.6 wt %. In some examples, the phosphor can be present in the polymer anti-reflective coating in an amount of from about 0 wt % (exceeding) to about 2 wt %; from about 0 wt % (exceeding) to about 1.8 wt %; from about 0 wt % (exceeding) to about 1.5 wt %; About 0.1 wt % (exceeding) to about 2 wt %; about 0.3 wt % (exceeding) to about 2 wt %; or preferably about 0.4 wt % (exceeding) to about 1.6 wt %; In some examples, the nano-oxide particles may be present in the polymeric anti-reflection coating in an amount of about 0 wt % (exceeding) to about 4 wt %; about 0 wt % (exceeding) to about 3 wt %; about 0 wt % (exceeding) to about 2 wt %; about 0.1 wt % to about 3 wt %; about 0.1 wt % to about 2 wt %; about 0.3 wt % to about 2 wt %; about 0.4 wt % to about 2 wt %. When included within the ranges mentioned in some examples, the surface reflection can be lowered and the stability due to UV light can be improved through the combination of the down-conversion effect of the phosphor particles (e.g., micro-sized particles) and the multiple scattering effect of the oxide nanoparticles.

According to one embodiment, the mass ratio of the phosphor to the nano oxide particles can be from about 1: about 10 to about 1: about 1; preferably from about 1: about 5 to about 1: about 1. When included within the range mentioned in any example, the surface reflection can be lowered and the stability by UV light can be improved through the combination of the down-conversion effect of the phosphor particles and the multiple scattering effect of the oxide nanoparticles.

In one embodiment, the polymeric anti-reflection coating can be textured to reduce surface reflection and establish an optical design to convert potentially quality-degrading UV light into useful visible light by applying a phosphor.

According to one embodiment, the polymer anti-reflection film can apply micro-sized phosphors (e.g., phosphor particles) that absorb UV range and fluoresce in visible light range to overcome UV photostability, thereby improving photostability through light path improvement. That is, by adding phosphors to resolve parasitic absorption of ultraviolet (UV) light, UV light can be converted into visible light.

According to one embodiment, the polymer anti-reflection film can implement RGB by controlling the fluorescence area of the phosphor used in the anti-reflection film without additional technology for separate aesthetics. In some examples, the polymer anti-reflection film can be used in various fields such as not only photovoltaic devices but also solar power generation facilities (e.g., BIPV (Building Integrated Photovoltaic System) and VIPV (Vehicle Integrated Photovoltaic)) by utilizing such aesthetics.

According to one embodiment, the size of the phosphor may be about 1 um (micrometer) to about 5 um (micrometer). Here, the size of the phosphor may mean a particle diameter measured by a dynamic light scattering method (DLS method) calculated by the Stokes-Einstein equation.

According to one embodiment, the phosphor may include at least one or more of a green phosphor, a red phosphor, a blue phosphor, a yellow-red phosphor, and a green-yellow phosphor, or a combination thereof. According to one embodiment, the phosphor may include a garnet-type phosphor, a silicate-type phosphor, Sialon-based fluorescent substance, Sulfide fluorescent substance, Silicon oxynitride phosphors, oxynitride phosphors, It may include at least one or any combination of two or more of oxide-based phosphors, nitride-based phosphors (e.g., silicon nitride-based phosphors), and aluminate-based phosphors.

According to one embodiment, the phosphor may be a powdered phosphor that emits fluorescence (fluorescence of a longer wavelength than the excitation light) upon irradiation with an excitation light (e.g., a UV light region). In some examples, the phosphor may be a phosphor that converts a UV light region into a visible light region.

In some examples, light in a wavelength range of about 350 nm to about 480 nm is used as an excitation source, and the light may be selected from a green phosphor having an emission peak or center wavelength in a wavelength range of about 510 nm to about 560 nm; or about 520 nm to about 560 nm; a red phosphor having an emission peak or center wavelength in a wavelength range of about 600 nm to about 660 nm; or about 590 nm to about 650 nm; and a blue phosphor having an emission peak or center wavelength in a wavelength range of about 450 nm to about 480 nm; and about 460 nm to about 470 nm.

In some examples, the sulfide phosphor may be selected from, but is not limited to, CaS:Eu (red), SrS:Eu (red), (Sr, Ca)S:Eu (red), SrGa ₂ S ₄ :Eu (green), SrGa ₂ S ₄ :Eu, BaGa ₂ S ₄ :Eu, SrAl ₂ S ₄ :Eu(Ca, Sr, Ba)(Al, Ga, In) ₂ S ₄ :Eu (or, Ce), (Ca,Sr)S:Eu ^{2+ (} red), (Sr,Ca)Ga ₂ S ₄ :Eu 2+ (green), SrSi ₂ O ₂ N ₂ :Eu ²⁺ (green).

In some examples, the silicate-based phosphors are Ba ₂ SiO ₄ :Eu, Ca ₂ SiO ₄ :Eu, Sr ₂ SiO ₄ :Eu, Ba ₂ SrSiO ₄ :Eu, (Ba, Ca, Eu, Sr) ₂ SiO _4, (BaSr) ₃ SiO ₅ :Eu, (BaSr) ₂ SiO ₄ :Eu, Ca ₈ Mg(SiO ₄ ) ₄ Cl ₂ :Eu, Ca ₂ Sr ₂ MgSi ₂ O ₇ :Eu, Ca ₃ Sc ₂ Si ₃ O ₁₂ :Ce, (Sr,Ba,Ca,Mg,Zn) ₂ Si(OD) ₄ :Eu ²⁺ (D=F,Cl,S,N or Br)(green-yellow), Ba ₂ MgSi ₂ O ₇ :Eu ²⁺ , Ba ₂ SiO ₄ :Eu ²⁺ (green), Ca ₃ (Sc, Mg) ₂ Si ₃ O ₁₂ :Ce ³⁺ (green), etc., but are not limited thereto.

In some examples, the nitride-based (or silicon nitride-based) phosphors may be selected from, but are not limited to, BaSi ₂ O ₂ N ₂ :Eu, SrSi ₂ O ₂ N ₂ :Eu, CaSi ₂ O ₂ N ₂ :Eu, Ba ₃ Si ₆ O ₁₂ N ₂ :Eu, CaAlSiN ₃ :Eu ²⁺ (red), (Sr,Ca)AlSiN ₃ :Eu ²⁺ (yellow-red), Sr ₂ Si5N8:Eu ²⁺ (red).

In some examples, the sialon-based phosphor may be selected from, but is not limited to, β-SiAlON:Re and β-SiAlON:Eu.

In some examples, the oxide phosphors may be selected from, but are not limited to, Sr ₄ Al ₁₄ O ₂₅ :Eu, CaSc ₂ O ₄ :Ce, SrAl ₂ O ₄ :Eu, SiAlON:Ce ³⁺ (cyan), β-SiAlON:Eu ²⁺ (green-yellow), Ca-α-SiAlON:Eu ²⁺ (orange), Ba ₃ Si ₆ O ₁₂ N ₂ :Eu ²⁺ (green). In some examples, the aluminate phosphor may be selected from, but is not limited to, (Y, Gd) ₃ (Al, Ga) ₅ O ₁₂ :Ce (blue), (Sr, Ba)Al ₂ O ₄ :Eu ²⁺ (blue), (Mg, Sr)Al ₂ O ₄ :Eu ²⁺ (blue), BaMg ₂ Al ₁₆ O ₂₇ :Eu ²⁺ (blue).

1.9)로 인해 ARC 필름의 반사율을 증가시킬 수 있고, 이러한 형광체의 후방 산란 문제(backward scattering problem)는 나노 산화물 분말 (예: 구형의 SiO₂ 나노입자)을 추가하여 보완할 수 있다. 어떤 예에서 텍스처화된 고분자 반사방지코팅(ARC) 필름의 광학적 특성은 큰 형광체 입자의 하향 변환 효과와 나노 산화물 분말(예: SiO₂ 나노입자)의 다중 산란 효과를 결합하여 개선시킬 수 있다. According to one embodiment, the polymer anti-reflection film can be set by simulating an optical operation design using the Mie scattering effect to overcome light loss due to backscattering by a micro-sized fluorescent substance, and can be introduced into the polymer anti-reflection film together with the fluorescent substance. This can contribute to improving the optical performance and efficiency of the photovoltaic device. In some examples, the nano-oxide powder (e.g., SiO ₂ nanoparticles) of the polymer anti-reflection film can increase the diffusion transmittance and reduce the reflectance. In some examples, the embedded fluorescent substance has a large particle size (e.g., > about 5 μm) and a high refractive index (e.g., n

1.9) can increase the reflectivity of the ARC film, and the backward scattering problem of these phosphors can be compensated by adding nano-oxide powders (e.g., spherical SiO ₂ nanoparticles). In some examples, the optical properties of textured polymeric anti-reflective coating (ARC) films can be improved by combining the down-conversion effect of large phosphor particles and the multiple scattering effect of nano-oxide powders (e.g., SiO ₂ nanoparticles).

According to one embodiment, the nano-oxide particles may have a size of about 30 nm (nanometers) to about 400 nm (nanometers); about 30 nm (nanometers) to about 340 nm (nanometers); about 30 nm (nanometers) to about 300 nm (nanometers); about 30 nm (nanometers) to about 250 nm (nanometers); about 30 nm (nanometers) to about 200 nm (nanometers); about 40 nm (nanometers) to about 150 nm (nanometers); about 50 nm (nanometers) to about 100 nm (nanometers); or preferably about 30 nm (nanometers) to about 100 nm (nanometers). In some examples, the size may be a length, a diameter, a thickness, or the like depending on the shape of the particle. In some examples, the nano-oxide particles may be spherical, polyhedral, beaded, oval, or the like. It is possible to prevent the required optical properties and stability from being deteriorated due to backscattering of a fluorescent substance within an antireflection film, including a range of sizes mentioned in some examples. In addition, it is possible to prevent the reflectivity from increasing or the light transmittance from decreasing due to an increase in the size of the nano oxide particles.

According to one embodiment, the nano-oxide particles may include oxide particles having a light-scattering function, and the nano-oxide particles may include light-scattering particles including at least one or more of silica, antimony oxide, boron oxide, calcium oxide, titanium oxide, magnesium oxide, barium oxide, aluminum oxide, bismuth oxide, zirconium oxide, tin oxide, tungsten oxide, strontium oxide, niobium oxide, zirconium oxide, and zinc oxide, or a combination thereof. In some examples, the nano-oxide particles may be applied by being mixed with organic beads such as styrene and acrylic.

In one embodiment, the polymer anti-reflective film may have a thickness of from about 50 um (micrometers) to about 300 um (micrometers); or preferably from about 100 um (micrometers) to about 200 um (micrometers). In one embodiment, the polymer anti-reflective film may have a light transmittance of from about 90 % or greater; from about 95 % or greater; or from about 90 % to about 97 %.

According to one embodiment, a method for manufacturing a polymer anti-reflection film according to embodiments of the present disclosure may include: preparing a base resin composition including a polymer resin and a curing agent; adding and mixing a fluorescent dispersion into the base resin composition; removing a solvent of the dispersion from the mixed composition of the fluorescent dispersion and the base resin; adding and mixing oxide particles; and curing after coating on a substrate.

In one embodiment, the polymer resin, the fluorescent substance, and the oxide are as mentioned in the polymer anti-reflection film. In one embodiment, the curing agent can be appropriately selected depending on the type of the polymer or the curing method, and can be applied without limitation as long as it is applicable to the curing process for forming the film. For example, it may be Sylgard 170, Sylgard 184, or Sylgard 186, but is not limited thereto. For example, the curing agent may be included in an amount of about 0.01 wt % to about 2 wt %; about 0.01 wt % to about 1.5 wt %; about 0.01 wt % to about 1 wt %; or about 0.1 wt % to about 1 wt % with respect to the polymer resin.

According to one embodiment, the phosphor dispersion comprises about 0.1 wt % to about 2 wt % of the phosphor and a solvent, more preferably about 0.4 wt % to about 1.6 wt %, wherein the solvent can be applied without limitation as long as it is capable of dispersing the phosphor, and may be, for example, methanol, ethanol, etc.

In one embodiment, the step of removing the solvent may remove the solvent applied to the phosphor dispersion under vacuum. In some examples, the solvent may be a solvent having a boiling point of about 100° C. or less; about 90° C. or less; about 80° C. or less; about 70° C. or less; or about 50° C. or less, and may preferably be ethanol. In some examples, the solvent may be removed at a temperature of room temperature to about 100° C.; room temperature to about 90° C.; room temperature to about 80° C.; or about 30° C. to about 50° C.

According to one embodiment, the coating may be applied by any known coating method without limitation, for example, but not limited to, spin coating, spray coating, bar coating, print coating, etc.

In one embodiment, a photovoltaic device comprising a polymer anti-reflective film according to embodiments of the present disclosure can be provided. In one embodiment, the photovoltaic device can include a perovskite solar cell, a silicon solar cell, or both. In some examples, the photovoltaic device can include a monolithic perovskite solar cell layer; and a silicon tandem solar cell layer. In some examples, in the photovoltaic device, the polymer anti-reflective film can be positioned on the monolithic perovskite solar cell layer.

In one embodiment, the perovskite solar cell may include a configuration known in the art related to the present disclosure, which is not specifically mentioned in this document. For example, it may include a first electrode and a second electrode, and a perovskite light-absorbing layer between the first electrode and the second electrode. In one embodiment, it may further include functional layers, such as a hole transport layer, a perovskite passivation layer, an electron transport layer, a buffer layer, and the like.

In one embodiment, the perovskite may be an inorganic metal halide perovskite, an organic-inorganic hybrid perovskite, or the like. For example, the perovskite may have a structure represented by a chemical formula such as ABX ₃ , A ₂ BX ₄ , ABX ₄ , APbX _{3 ,} A _n-1 Pb _n I _3n+1 (wherein n is an integer from 2 to 6). In some examples, the perovskite may be a mixture of one kind, two kinds, or three or more kinds. In some examples, in the chemical formula, A is an alkali metal, an organic cation (e.g., organoammonium), and/or an inorganic cation, B is a metal material, and X may be selected from a halogen anion, a chalcogenide anion, and SCN-(thiocyanate). For example, A may be an alkali metal such as Na, K, Rb, Cs, or Fr; (CH ₃ NH ₃ ) _n , ((C _x H _2x+1 ) _n NH ₃ ) ₂ (CH ₃ NH ₃ ) _n , (RNH ₃ ) ₂ , (C _n H _2n+1 NH ₃ ) ₂ , (CF ₃ NH ₃ ), (CF ₃ NH ₃ ) _n , ((C _x F _2x+1 ) _n NH ₃ ) ₂ (CF ₃ NH ₃ ) _n , ((C _x F _2x+1 ) _n NH ₃ ) ₂ or (C _n F _2n+1 NH ₃ ) ₂ (n is an integer greater than or equal to 1, x is an integer greater than or equal to 1), and B is a divalent transition metal, rare earth metal, alkaline earth metal, Pb, Sn, Ge, Ga, In, Al, Sb, Bi, Po, etc. (e.g. (e.g. Be, Mg, Ca, Sr, Ba, Fe, (selected from Cd, Co, Ni, Cu, Ag, Au, Hg, Sn, Ge, Ga, Pb, In, Tl, Sb, Bi, Ti, Zn, Cd, Hg, Mn, Ge, Eu and Zr), and X is P, Cl, Br, I, etc. In some examples, the perovskite may be CH ₃ NH ₃ PbI ₃ , CH ₃ NH ₃ PbBr ₃ , CH ₃ NH ₃ PbI ₂ Cl, CH ₃ NH ₃ PbI ₂ Br, etc. In some examples, when two or more of the perovskite compounds are included, the ratio of the first perovskite compound to the second perovskite compound may be 5:5 to 9:1. In some examples, further, a compound represented by chemical formulas such as NaX', ZnX', KX', and CsX'(X' is selected from Cl, Br, and I) may be included, and may be included in an amount of about 10% or less; or about 5% or less, of the total perovskite compound.

According to one embodiment, the silicon solar cell may include a configuration known in the art of the present disclosure, for example, a structure including a glass substrate, a silicon wafer, a transparent electrode layer, a p-type amorphous silicon layer, an i-type amorphous silicon layer, an n-type amorphous silicon layer, a hole transport layer, an organic photoactive layer, and a metal electrode layer, which are sequentially stacked. The known configuration may further be included as needed.

According to one embodiment, the hole transport layer or the electron transport layer is selected from the group consisting of titanium (Ti) oxide, zirconium (Zr) oxide, strontium (Sr) oxide, zinc (Zn) oxide, indium (In) oxide, lanthanum (La) oxide, vanadium (V) oxide, molybdenum (Mo) oxide, tungsten (W) oxide, tin (Sn) oxide, niobium (Nb) oxide, magnesium (Mg) oxide, aluminum (Al) oxide, yttrium (Y) oxide, scandium (Sc) oxide, samarium (Sm) oxide, gallium (Ga) oxide, strontium-titanium (Sr-Ti) oxide, lithium fluoride (LiF), poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate), PEDOT:PSS), polyaniline, polypyrrole P3HT (poly[3-hexylthiophene]), Spiro-OMeTAD (2,2',7,7'-tetrakis(N,N-di-p-methoxyphenylamine) 9,9'-spirobifluorene), PTB7 (Poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4- b]thiophenediyl]]), MDMO-PPV(poly[2-methoxy-5-(3',7'-dimethyloctylacyl)]-1,4-phenylenevinylene), It may include at least one or more of MEH-PPV(poly[2-methoxy-5-(2''-ethylhexyloxy)-p-phenylene vinylene]), P3OT(poly(3-octyl thiophene)), POT( poly(octyl thiophene)), P3DT(poly(3-decyl thiophene)), P3DDT(poly(3-dodecyl thiophene), PPV(poly(p-phenylene vinylene)), TFB(poly(9,9'-dioctylfluorene-co-N-(4-butylphenyl)diphenyl amine), polyaniline, F8BT(poly(9,9′-dioctylfluorene-cobenzothiadiazole), PEDOT (poly(3,4-ethylenedioxythiophene)), PTAA(poly(triarylamine)), poly-TPD(poly(4-butylphenyldiphenyl-amine)), and copolymers thereof, or combinations thereof, but is not limited thereto.

According to one embodiment, the first electrode includes at least one of ITO, IZO, FTO and AZO, and the second electrode may include at least one metal selected from the group consisting of Ag, Au and Al or may be a gold electrode, but is not limited thereto.

Hereinafter, the present invention will be described in more detail by examples and comparative examples.

However, the following examples are only intended to illustrate the present invention, and the content of the present invention is not limited to the following examples.

Example

Fabrication of Textured Si Mold :

The Si substrate was first cut (e.g., square pieces, 30 mm Х 30 mm), then ultrasonically cleaned with acetone, deionized water, and ethanol for 10 min each. The Si substrate was immersed in buffered oxide etchant (BOE) to remove the native oxide film on the Si substrate surface before wet etching. After that, the Si sample was rinsed with DI water and dried using N ₂ gas flow. To fabricate the micro-pyramidal Si mold, the Si substrate was immersed in potassium hydroxide solution at 95 °C for 10 min, then chemically wet etched in a mixed solution of KOH, IPA, and DI water (8:5:100 v/v) at 70 °C for 40 min. The sample was rinsed with DI water and dried with N ₂ gas.

30 nm SiO ₂ NPs were purchased from Research Nanomaterials, Inc., USA. 100 nm, 340 nm, and 1300 nm SiO ₂ NPs were was synthesized by the method. _NH4OH (3 mL for 100 nm and 4.5 mL for 340 nm) and ethanol (50 mL) were mixed with magnetic stirring (approximately 500 rpm) overnight at room temperature to prepare a homogeneous solution. Tetraethyl orthosilicate (TEOS, 1.5 mL) was added dropwise to the solution while stirring.

The solution was stirred continuously for 12 h to form a transparent silica sol. The silica particles were collected by centrifugation at 8000 rpm for 20 min and then redispersed in ethanol three times. For 1300 nm, the seed solution (500 nm SiO ₂ ) was prepared by slowly adding TEOS (3.9 mL) to a solution of NH ₄ OH (10.75 mL) and ethanol (50 mL). The seed solution was then mixed with NH ₄ OH (11.8 mL), ethanol (50 mL), and TEOS (4.2 mL) to form 1300 nm SiO ₂ NPs. The solution was maintained at room temperature with magnetic stirring (500 rpm) for 24 h.

Manufacturing of Antireflective Coating Film:

Silicate-based green phosphors (SGA 550 100 isiphor) were purchased from "Merck KgaA, Darmstadt, Germany." To prevent agglomeration of the phosphor, the powder was first dispersed in ethanol (ethanol:powder ratio = 15:1 to 30:1) using ultrasonic treatment and added to the PDMS solution at volume percentages of 0.0%, 0.4%, 0.8%, 1.2%, and 1.6%. The PDMS solution was prepared using a mixture of base resin and curing agent (10:1 wt%) (Sylgard 184, Dow Corning Co.). After ethanol was completely removed by vacuum for 2 h, SiO ₂ particles were added to the solution and mixed carefully. The PDMS solution containing the phosphor and SiO ₂ particles was poured into a textured Si mold and cured at 65 °C overnight. The film is transferred to the top surface of a perovskite/Si tandem solar cell.

Si Solar Cell Fabrication:

Monocrystalline Si wafers (1-5 Ω cm, p-type, CZ, 525 μm) were cleaned using the RCA cleaning procedure. 2 μm thick aluminum was deposited on the back side of the Si wafers using an e-beam evaporator. Spin-on dopant (Filmtronics SOD P507) was spin-coated on the front side of the Si wafers. The doping level was controlled and optimized using a rapid thermal annealing (RTA) system. An emitter with a sheet resistance of 100 ohms sq ^-q was formed on the front side, and a P+Al BSF (Al-back-surface-field) was formed on the back side. The residual phosphorous silicate glass was oxidized using the RTA system and removed with hydrofluoric acid. Alternatively, a 1 μm Ag metal electrode was deposited on the back side using an e-beam evaporator. Finally, a 20 nm thick ITO was deposited using an RF magnetron sputtering process to form a recombination layer.

Fabrication of Perovskite Solar Cell and Tandem Solar Cell:

A PTAA solution (2 mg mL ^-L in chlorobenzene) was spin-coated on the substrate at 6000 rpm for 30 s and annealed at 100 °C for 10 min. A 0.5 mg mL ^-1 PFN-Br solution in methanol was spin-coated on the PTAA HEL at 5000 rpm for 30 s. To prepare the Cs _0.05 (FA _0.83 MA _0.17 ) _0.95 Pb(I _0.75 Br 0.25) ₃ mixed perovskite solution, 1.35 M FAPbI ₃ with 10% excess PbI ₂ and 1.35 M MAPbBr ₃ were dissolved in N,N-dimethylformamide (DMF)/dimethyl sulfoxide (DMSO) (4:1 v/v) solvent; and 1.5 M CsI stock solution in DMSO were prepared separately. Next, FAPbI ₃ , MAPbBr ₃ , and CsI solutions were mixed in a volume ratio of 750:250:53.7. The mixed perovskite solution was cast by an antisolvent dropping method. The spin coating consisted of spinning at 5000 rpm for 1.7 s during the ramping time and spinning at 5000 rpm for 30 s during the holding step. After 10 s, the spinning substrate was washed with 300 μL ethyl acetate as an antisolvent.

Next, the perovskite films were annealed at 100 °C for 1 h. The PCBM (OSM) solution (20 mg mL ^-L in chlorobenzene) was spin-coated at 4000 rpm for 30 s, and the ZnO solution (Avantama) was also coated under the same conditions, followed by annealing at 100 °C for 1 min. After that, a 100 nm thick Ag electrode was deposited using an e-beam evaporator. The monolithic perovskite/Si tandem solar cell was fabricated by applying the semitransparent perovskite solar cell process on the tandem-oriented bottom Si solar cell.

Characteristic Analysis Method

The device area defined by the shadow mask is 0.25 cm ² . The J-V characteristics of perovskite/Si tandem solar cells were measured under AM 1.5G (100 mWcm ^-2 ) conditions with an aperture mask (0.25 cm ² ). The IPCE spectra were measured using a QE measurement system (Newport) under ambient conditions and monochromatic illumination from a Xenon lamp. The total transmittance and diffuse transmittance were measured using a UV-vis-NIR spectrophotometer with a 100 nm diameter integrating sphere (LAMBDA 750, Perkin Elmer). Photoluminescence (PL) measurements were performed using a spectrofluorometer (QuantaMaster, PTI). The excitation and emission spectra were recorded in the range of 280–480 nm and 400–680 nm, respectively, with a resolution of 1 nm.

FIG. 1a is a schematic diagram of a PDMS-based anti-reflection film including SGA phosphor and SiO ₂ nanoparticles. FIG. 1b is an image of the PDMS-based anti-reflection film including SGA phosphor and SiO ₂ nanoparticles under ambient light and UV light (λ = 365 nm). FIG. 1c is a schematic diagram of a perovskite/Si tandem solar cell with a PDMS-based anti-reflection layer including SGA phosphor and SiO ₂ nanoparticles. FIG. 1d is a cross-sectional SEM image of the perovskite-Si solar cell.

The device comprised of monolithic perovskite/Si tandem solar cells embedded with SGA phosphors and SiO ₂ nanoparticles in a textured PDMS film used as an anti-reflection coating (ARC) film to control the reflectance of visible light and parasitic absorption of UV light.

A commercially available SGA phosphor is selected as a luminophore to provide UV down-conversion capability to the ARC film, and a schematic diagram of the ARC film embedded with SGA phosphor and SiO ₂ nanoparticles and the tandem solar cell with the ARC film are shown in Fig. 1a and Fig. 1c. The textured PDMS film is designed to have a micro pyramid texture shape with a width and height of 3-5 μm. Large SGA phosphor and small SiO ₂ nanoparticles are mixed into the PDMS film, which is attached to the IZO film. Fig. 1b is a photograph of the ARC film under ambient light and UV light (λ = 365 nm), and the strong yellow-green light under UV light confirms the uniform distribution of the phosphor.

Figure 1d is a cross-sectional SEM image of the perovskite/Si tandem cell, with the stacked structure (poly[bis(4-phenyl)(2,4,6-trimeth-ylphenyl)amine] (PTAA)/mixed perovskite/[6,6]-Phenyl-C61-bu-tyric acid methyl ester (PC61BM)/ZnO/indium zinc oxide (IZO)) of the upper perovskite solar cell. In the upper cell, the PC61BM/ZnO layer serves as an electron-selective layer, and the 100 nm thick IZO layer serves as a transparent conductive electrode for top illumination. The mixed halide perovskite layer (Cs0.05FA0.75MA0.20)Pb(I0.75Br0.25)3 absorbs most of the visible light. The bottom cell is a p-type Si solar cell with an aluminum back-surface field (BSF) layer to convert near-infrared light into electricity. The thickness of the perovskite layer is controlled to 340 nm for optimal current matching between the top and bottom cells. Referring to Fig. 6a, the PC61BM/ZnO/IZO layer (i.e., ETL) provides transparency to the top illumination, but has a current density (mA cm ^-2 ) loss of 1.08 due to parasitic absorption in the UV region. The device structure of the present disclosure is designed to minimize UV light loss due to parasitic absorption of the PC61BM/ZnO/IZO and maximize diffuse transmittance. That is, the device structure of the present disclosure can provide an increase in the efficiency of the photovoltaic device by introducing an antireflection film with micro-phosphors (or, mixed with SiO ₂ nanoparticles).

Fig. 2a is the excitation (λ _ex : 380 nm) and emission (λ _em : 530 nm) of the SGA phosphor (inset: SEM image of the SGA phosphor), Fig. 2b is the total transmittance, Fig. 2c is the diffuse transmittance, and Fig. 2d is the reflectance of the ARC film on glass as a function of the volume % of the SGA phosphor. Fig. 2e is the JV and f)IPCE curves of the tandem solar cell using the same film.

Figure 2a shows the PL excitation (black curve) and PL emission (red curve) spectra of the SGA phosphor. The SEM image of the SGA phosphor in Figure 2a shows that the particle size is 3–8 μm. The SGA phosphor absorbs light in the range of 280 nm to 470 nm, and the peak absorption appears at 380 nm, which overlaps with the parasitic absorption spectrum of perovskite/silicon tandem solar cells. The emission of SGA occurs in the range of 450 nm to 660 nm, which can be utilized by the perovskite layer. Therefore, this commercial phosphor serves as a downconversion material for perovskite/Si tandem solar cells.

To systematically investigate the effect of phosphor on the optical properties of ARC films, a series of composite films with only SGA phosphor were fabricated at five different volume concentrations (0%, 0.4%, 0.8%, 1.2%, and 1.6%). The films are denoted as ARC, ARC_SGA(0.4), ARC_SGA(0.8), ARC_SGA(1.2), and ARC_SGA(1.6), respectively. Figures 2b-2d show the total transmittance, diffuse transmittance, and reflectance of the ARC_SGA films on glass. Figures 2e-2f show the PCE and photon to current conversion efficiency (IPCE) of perovskite/silicon tandem solar cell devices with ARC films as a function of volume concentration.

Devices with and without ARC film exhibited Jsc of 14.70 and 16.02 mA cm ^-2 , Voc of 1.75 and 1.75 V, and FF of 80.23% and 80.18%.

As a result, the PCE is improved from 20.64% to 22.48%. The textured surface of the pure PDMS film (ARC) contributes to reducing the reflectance and trapping the incident light. When ARC_SGA (0.4) is applied to the device, Jsc and PCE increase to 16.21 mA cm ^-2 and 22.75%, respectively. The IPCE curve in Fig. 2f clearly shows that the addition of SGA increases the IPCE in the UV region by utilizing UV light with parasitic absorption problem.

1.7-1.9)과 더 큰 크기(직경

5 μm)가 전체 투과율을 감소시키기 때문이다(도 2b). SGA 입자의 크기가 입사광의 파장보다 크기 때문에 SGA는 또한 SGA-PDMS 계면에서 후방 산란을 증가시키고 확산 투과율을 감소시키는 데 기여한다(도 2c). A small amount of SGA increases the IPCE in the visible range. The total transmittance of ARC_SGA(0.4) is slightly lower than that of ARC, but ARC_SGA(0.4) slightly increases the diffuse transmittance in the visible range and improves the IPCE. However, the PCE of the device decreases as the volume concentration of SGA increases. This is due to the high refractive index (n) of SGA.

1.7-1.9) and larger sizes (diameter

5 μm) reduces the overall transmittance (Fig. 2b). Since the size of the SGA particles is larger than the wavelength of the incident light, the SGA also contributes to increasing the backscattering at the SGA-PDMS interface and reducing the diffuse transmittance (Fig. 2c).

The results in Fig. 2a to 2f suggest that SGA can convert UV light into electricity without parasitic absorption problems. However, it increases the reflectivity and reduces the overall current of the solar cell. For high-performance solar cells, the backscattering of visible and near-infrared (NIR) light should be suppressed.

Figures 3a to 3f show the results of analyzing the increase in efficiency of a photovoltaic device due to the introduction of SiO ₂ nanopowder.

Fig. 3a is a SEM image of SiO ₂ nanoparticles, Fig. 3b is total transmittance, and Fig. 3c is diffuse transmittance. Fig. 3d is reflectance of textured ARC_S (0.8) on glass and textured ARC film on glass and glass. Fig. 3e is J-V curve and IPCE curve of the tandem solar cell without the same film and with the same film.

1.46)와 PDMS(n

1.39) 사이의 굴절률 차이가 작고, 구형이며 크기가 작기 때문에 SiO2 나노입자를 첨가하면 광학적 손실 없이 입사광의 순방향 산란이 강화될 것으로 예상된다. To address this issue, SiO ₂ spherical nanoparticles with a diameter of 100 nm, as shown in Fig. 3a, were added to the ARC film and the forward scattering power was investigated. SiO ₂ (n

1.46) and PDMS(n

1.39) is small, and the addition of SiO2 nanoparticles is expected to enhance the forward scattering of incident light without optical loss because the difference in refractive index between the two is small, and the particles are spherical and small in size.

Here, we show the total transmittance of SiO ₂ particles in glass as a function of size at the same volume concentration (0.8 vol.%). The total transmittance of SiO ₂ particles of 30 nm in glass is lower than that of glass. As the nanoparticle size increases to 100 nm, the total reflectance also increases. This is because the increase in nanoparticle size increases the ratio of forward scattering power/backward scattering power in the Mie scattering mode. However, as the particle size approaches the wavelength of the incident light, the incident light starts to be reflected. This is the case for SiO ₂ particles of 340 nm and 1300 nm in diameter. That is, the transmittance decreases again due to reflectance. Therefore, SiO ₂ nanoparticles of 100 nm in diameter are selected to increase the forward scattering of the ARC film. The textured PDMS film containing 100 nm SiO ₂ nanoparticles at 0.8 vol.% is denoted as ARC_S(0.8). Figures 3b-3d show the total transmittance, diffuse transmittance, and reflectance of ARC and ARC_S(0.8). Unlike SGA, SiO ₂ nanoparticles (0.8 vol.%) slightly increase the transmittance of ARC. The total reflectance of ARC_S(0.8) is lower than that of ARC, which is more prominent in the NIR region.

This is because the SiO ₂ nanoparticles increase the diffuse transmittance through multiple scattering. As can be seen in Fig. 3c, the difference in diffuse transmittance between ARC and ARC_S(0.8) becomes more pronounced as the wavelength increases. Therefore, the reflectance of ARC_S(0.8) is lower than that of ARC (Fig. 3d). The average reflectances in the UV, vis, and NIR regimes are 5.6% for ARC and 4.4% for ARC_S(0.8). The current obtained by integrating the reflectance (i.e., reflection loss) decreases from 2.48 (ARC) to 1.92 mA cm ^-2 (ARC_S(0.8)).

Figure 3e shows the effect of ARC and ARC_S(0.8) on the performance of perovskite/silicon tandem solar cells. Compared with the PCE (20.64%) of the control sample without ARC, the PCE of the devices with ARC and ARC_S(0.8) are 22.48% and 23.26%, respectively. This is attributed to the increase of Jsc by 0.56 mA cm ^-2 . Figure 3f indicates that the addition of 100 nm SiO ₂ nanoparticles increases the IPCE throughout the entire range, and the improvement is more prominent in the NIR region where the diffuse transmittance accounts for > 90% of the total transmittance. This is because the decrease in reflectance and the increase in the effective thickness of the light absorbers (perovskite layer and Si layer) facilitate the conversion of incident photons into electricity.

Figure 4a is a schematic diagram of the FDTD simulation setup for the single particle (SiO2@Air) scattering model and the multiple scattering model. For the single scattering model, 100 nm sized SiO ₂ particles with a 10 nm air gap (SiO2@Air) are added as scatterers in the PDMS matrix (0.8 vol.%). For the multiple scattering model, 729 SiO ₂ @Air particles are randomly distributed in the PDMS with the same vol.%. The refractive indices of PDMS and SiO ₂ are 1.39 and 1.46 at 623 nm, respectively. Figure 4b is the normalized scattering cross sections for PDMS only, single scattering of SiO ₂ @Air, and multiple scattering of SiO ₂ @Air system. Figure 4c is the estimated specular transmittance for a 150 μm thick film based on the scattering cross sections results. The air/PDMS and PDMS/substrate interface conditions are not considered.

To better understand the diffuse scattering observed in Fig. 3c, 3D finite-difference time domain (FDTD) simulations for the scattering effect were performed and the diffuse transmittance was separated from the specular transmittance. Two models are used to estimate the multiple scattering effect on the diffuse transmittance of red and near-infrared light. A schematic of these two models is shown in Fig. 4a. For the single-scattering model, 100 nm-sized spherical SiO ₂ particles are added as scatterers into the PDMS matrix.

The refractive indices of PDMS and SiO ₂ are 1.39 and 1.46 at 623 nm, respectively, and the extinction coefficients are negligible in the simulated wavelength region. Since the observed scattering effect is significantly larger than that calculated using the refractive index difference between PDMS and SiO ₂ , the SiO ₂ interface is assumed to be imperfect. Therefore, a thin air gap of 10 nm thickness is added between the PDMS and SiO ₂ assuming that the PDMS-SiO ₂ interface is not perfectly matched.

For the multiple scattering model, the system is stretched nine times along the x, y, and z directions, and 729 SiO ₂ @Air particles are randomly distributed in the PDMS with the same ratio of 0.8 vol.%. Figure 4b shows the calculated scattering cross-section by normalizing the scattered power to the source intensity. The normalized cross-section of multiple scattering is obtained by dividing the calculated value by the number of particles (729) included in the simulation. This allows comparing the actual multiple scattering effect with the single scattering effect.

As can be seen in Fig. 4b, the calculated single-scatterer effect agrees well with the prediction of the Mie scattering theory. As the number of scatterers increases, the scattering cross-section increases rapidly, which becomes more pronounced in the long wavelength range. The relative integral increases by 113% at λ = 400 nm, 213% at λ = 750 nm, and 319% at λ = 1100 nm. As a result, the specular transmittance of the multiple-scattering system becomes much smaller than that of the single-scattering system in the red and NIR region. Figure 4c shows that the specular transmittance decreases from about 100% (only PDMS) to about 70% (PDMS + SiO ₂ NPs) for red and NIR light when multiple scattering is considered in the simulation process. A 30% reduction in specular transmittance due to the inserted SiO ₂ NPs can be confirmed from the experimentally observed diffuse transmittance in Fig. 3c.

To combine the downconversion effect and increased forward scattering, SGA particles and 100 nm SiO2 nanoparticles are co-added into the ARC films. Figures 5a and 5b show the total and diffuse transmittance of the ARC films containing both SGA phosphors and _SiO2 nanoparticles. Four volume concentrations of SGA (0.4, 0.8, 1.2, and 1.6 vol %) are selected and are named as ARC_S(0.8)SGA(0.4), ARC_S(0.8)SGA(0.8), ARC_S(0.8)SGA(1.2), and ARC_S(0.8) SGA(1.6). Comparing Figures 2 and 5 , the addition of _SiO2 NPs to ARC_SGA increases both the total and diffuse transmittance.

This is consistent with the simulation results in Fig. 4a and 4b, demonstrating the enhanced diffuse transmittance by SiO ₂ NPs. The multiple scattering of incident light by SiO ₂ nanoparticles suppresses the reflectance and increases the diffuse transmittance. Compared with ARC, ARC_S(0.8) SGA(0.8) shows much larger diffuse transmittance in the NIR region and similar reflectance in the visible region in Fig. 5b and Fig. S4 (Supporting Information).

This suggests that SiO ₂ NPs can compensate for the backscattering of large SGA particles. Figure 5c and 5d show the J-V curves and IPCE of tandem solar cells with different antireflection films. The perovskite/Si tandem solar cell with ARC_S(0.8)SGA(0.8) film exhibits a Jsc of 16.74 mA cm ^-2 , a Voc of 1.75 V, and a FF of 80.21% without hysteresis in Figure 5f.

The PCE of the tandem solar cell with ARC_S(0.8)SGA(0.8) is 23.50%, while that of the tandem solar cell with ARC_S(0.8) is 23.26%. This change in PCE is because the down-conversion of UV light (280 nm < λ < 430 nm) by SGA increases the Jsc (Fig. 5e). In addition, the UV stability can be enhanced by the ARC film including the phosphor.

Figure 6b shows the normalized PCE of perovskite solar cells with the structure of Au/Spiro-OMeTAD/Perovskite/TiO2/FTO with and without phosphor-embedded ARC under UV (365 nm) irradiation at a dose of 15 W cm ^-2 , which is a comparative analysis of UV stability before and after application of an antireflection film to a photovoltaic device vulnerable to UV photostability.

To clearly see the effect of UV stability on the solar cell performance in Fig. 6b, a perovskite solar cell with the structure of Au/Spiro-OMeTAD/Perovskite/TiO ₂ /FTO was used. The UV stability of the device is improved under UV (365 nm) irradiation at an irradiance of 15 W cm ^-2 due to the UV downconversion effect of the phosphor. The PCE of the device with ARC film can be maintained for 120 h while maintaining 91% of the initial value.

The effect of SGA phosphors on the improvement of IPCE in the UV region is clearly observed in Fig. 5d. However, for SGA concentrations >0.8 vol.%, the loss of Jsc due to increased reflectance offsets the gain of Jsc due to downconversion effect.

In one embodiment, the present disclosure can convert UV light and increase diffuse transmittance of incident light by embedding (Ba, Ca, Eu, Sr) ₂ SiO ₄ (silicate-based green phosphors; denoted as SGA) phosphors with a diameter of microsized (e.g., 3 μm to 10 μm) and SiO ₂ nanoparticles with a diameter of 100 nm into textured PDMS. The mixture of SGA phosphors and SiO ₂ nanoparticles can significantly reduce reflectance while suppressing parasitic absorption of UV light. This is because down conversion by the SGA particles reduces UV absorption and multiple scattering of the embedded nanoparticles (SiO ₂ nanoparticles) maximizes forward scattering power. Therefore, the PDMS-nanoparticle composite with textured shape can successfully improve the performance of perovskite/Si tandem solar cells. Compared with the pure PDMS texture film, the _textured PDMS-phosphor-SiO ₂ nanoparticle composite can increase the PCE of the perovskite/Si tandem cell from 22.48% to 23.50%.

In one embodiment, the present disclosure demonstrates that the combination of SiO ₂ nanoparticles and large micron-sized phosphor particles can convert UV to visible light and increase the total transmittance of an anti-reflection coating (ARC) film. Large phosphor particles embedded in PDMS-ARC can induce downconversion of UV light and increase diffuse reflectance, whereas addition of a small amount of SiO ₂ nanoparticles can compensate for the backscattering of large phosphor particles through multiple scattering, and enhance the diffuse transmittance especially in the long wavelength (e.g., red and NIR region). This optical engineering of PDMS-ARC by embedded particles can increase the PCE of perovskite/Si tandem solar cells. This improvement in PCE is mainly attributed to the increase in JSC due to suppression of reflectance and downconversion of UV light.

Although the embodiments have been described above by way of limited examples and drawings, those skilled in the art can make various modifications and variations from the above description. For example, appropriate results can be achieved even if the described techniques are performed in a different order from the described method, and/or the described components are combined or combined in a different form from the described method, or are replaced or substituted by other components or equivalents. Therefore, other implementations, other embodiments, and equivalents to the claims also fall within the scope of the following claims.

Claims (16)

transparent polymer; and
Micro fluorescent particles and nano oxide particles;
A polymer anti-reflection film comprising a mixture comprising:
At least one surface of the above polymer anti-reflection film comprises a textured surface having a three-dimensional structure,
The texture surface of the three-dimensional structure is continuous with the polymer anti-reflection film, and the texture surface includes a protrusion, a concave portion, or both due to the three-dimensional structure.
Polymer antireflection film.
In the first paragraph,
The above transparent polymer is,
A polymer anti-reflection film comprising at least one or more of PDMS (polydimethylsiloxane), PDPhS (polydiphenylsiloxane), PMPS (polymethylphenylsiloxane), EVA (ethylene-vinyl acetate copolymer), POE (poly olefin elastomer), PMMA (polymethyl metacrylate), TAC (triacetate cellulose), PET (polyethylene terephthalate), PEK (poly(ether ketone), polymer glass, polycarbonate (PC), and polyolefin, or a combination thereof.
In the first paragraph,
The above three-dimensional structures are arranged regularly or irregularly,
A polymer anti-reflection film, wherein the three-dimensional structure comprises at least one or more of a sphere, an ellipse, a cone, a polypyramid, a polygonal prism, a polygon, and a polyhedron, or a combination thereof.
In the first paragraph,
A polymer anti-reflection film, wherein the height of the protrusion and the depth of the concave portion are each 1 um (micrometer) to 10 um (micrometer).
In the first paragraph,
A polymer anti-reflection film, wherein the micro fluorescent particles and nano oxide particles are present in an amount of 0 wt% (exceeding) to 6 wt% of the polymer anti-reflection film.
In the first paragraph,
A polymer anti-reflection film, wherein the mass ratio of the micro fluorescent particles to the nano oxide particles is 1:10 to 1:1.
In the first paragraph,
A polymer anti-reflection film, wherein the size of the above micro fluorescent particles is 1 um (micrometer) to 5 um (micrometer).
In the first paragraph,
The above micro fluorescent particles include at least one of a red fluorescent substance, a green fluorescent substance and a blue fluorescent substance; or a combination thereof.
Polymer antireflection film.
In the first paragraph,
A polymer anti-reflection film, wherein the micro fluorescent particles include at least one or more of a silicon-based fluorescent substance, a nitride-based fluorescent substance, and an oxide-based fluorescent substance, or a combination thereof.
In the first paragraph,
A polymer anti-reflection film, wherein the size of the nano oxide particles is 30 nm (nanometers) to 400 nm (nanometers).
In the first paragraph,
The above nano oxide particles include oxide particles having a light scattering function,
A polymer anti-reflection film, wherein the nano oxide particles include light-scattering particles or a combination thereof, including at least one of silica, titanium oxide, magnesium oxide, barium oxide, aluminum oxide, bismuth oxide, zirconium oxide, tin oxide, tungsten oxide, strontium oxide, niobium oxide, zirconium oxide, and zinc oxide.
In the first paragraph,
A polymer anti-reflection film having a light transmittance of 90% or more.
In the first paragraph,
A polymer anti-reflection film having a thickness of 50 um (micrometers) to 300 um (micrometers).
A photoelectric device comprising a polymer antireflection film according to claim 1,
The above photoelectric element
Monolithic perovskite solar cell layer; and
Silicon tandem solar cell layer;
Including,
A photovoltaic device comprising the polymer antireflection film on the monolithic perovskite solar cell layer. delete delete