A perovskite nanocrystal fluorescent solar collector

Abstract

The invention belongs to the technical field of optical elements, and specifically discloses a perovskite nanocrystal fluorescent solar collector, wherein the collector comprises a fluorescent layer, a band-stop filter located on the top of the fluorescent layer, a silver nanowire array located on the bottom surface of the fluorescent layer, a coupling layer located below the fluorescent layer, and a bottom glass substrate; the invention utilizes the band-stop filter above the fluorescent layer to reflect fluorescent photons, thereby reducing top fluorescent leakage and greatly reducing surface escape cone loss; utilizes the silver nanowire array on the bottom surface of the fluorescent layer to introduce scattering effect and surface plasma resonance effect into the fluorescent layer, and induces Fabry-Perot standing wave resonance with the band-stop filter, thereby improving the absorption of the perovskite nanocrystal fluorescent layer; utilizes the coupling layer below the silver nanowire array to extract fluorescent photons to the glass substrate, thereby reducing the probability of fluorescence being secondary absorbed by other nanocrystals, and effectively suppressing reabsorption loss.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical elements, and relates to a perovskite nanocrystal fluorescent solar concentrator, and in particular to a perovskite nanocrystal fluorescent solar concentrator containing a glass substrate and having a band-stop filter, a silver nanowire array, and a coupling layer. Background Art

[0002] In 1976, Weber and Lamer of Ford Laboratory in the United States proposed a solar photon concentrator that is more economical than traditional concentrators, namely fluorescent solar concentrators (LSCs). Fluorescent solar concentrators are mainly composed of luminescent materials and transparent substrates. The luminescent materials distributed in the transparent substrate absorb sunlight and emit photons of specific wavelengths, which are concentrated to the edge through total internal reflection in the substrate layer. Small photovoltaic cells installed on the edge of the transparent substrate collect these photons and convert them into electrical energy.

[0003] To achieve the ambitious goal of net zero energy consumption in buildings, building-integrated photovoltaics have the potential to revolutionize future urban architecture. LSCs can play an important role in this transformation by providing a way to realize semi-transparent photovoltaic windows that can transform the passive energy facades of urban buildings into distributed energy generation units.

[0004] At present, the mainstream luminescent materials include inorganic phosphors, organic dyes and nanocrystals. Although inorganic phosphors have a large Stokes shift, they are less efficient for LSCs, and organic dyes also have the disadvantage of limited spectral absorption range. In contrast, nanocrystals have obvious advantages. Their absorption threshold can be adjusted by reasonably selecting the particle diameter. Some nanocrystals also have a large Stokes shift, and their crystalline semiconductor composition makes them more stable than organic dyes. Lead halide perovskite nanocrystals have attracted widespread attention in the field of fluorescence applications due to their low processing cost and high photoluminescence quantum yield (PLQY). For example, Tong et al. reported in J.Name., 2013, 00, 1-3. prepared a low-cost, high-emissivity, and stable formamidinium lead bromide nanocrystal-polystyrene film collector. For example, Zhong et al. reported in Adv. Mater. 2016, 28, 9163–9168. used an in-situ growth strategy to embed perovskite nanocrystals into a polymer matrix to prepare a perovskite nanocrystal-polyvinylidene fluoride (PVDF) composite luminescent film, which not only has high quantum efficiency, but also greatly improves the water and oxygen stability of the luminescent film. For example, Xia et al. reported in Sol. RRL 2021, 2100491. Use methylamine lead iodine nanocrystal-PVDF luminescent film to prepare a light collector and proposed a connectable LSCs assembly scheme, which significantly reduced the manufacturing and installation costs and improved the feasibility of commercial applications.

[0005] As a photonic device for solar energy conversion and collection, LSCs need to enhance the light absorption of the fluorescent layer as much as possible. When the frequency of the incident light is consistent with the inherent oscillation frequency of the free electrons, a surface plasmon resonance (SPR) is formed, which will lead to a significant increase in the local electric field mode density around the particles. Using the surface plasmons (SPP) of metal nanostructures, a good light trapping effect can be achieved, so that more incident light is localized in the active layer, thereby improving the absorption of the active layer. In the field of solar cells, as reported in Chinese Optics. 2020, 13(6), 1362-1384., Wang et al. designed and introduced a silver (Ag) nanoparticle array on the surface of the silicon (Si) absorption layer, and used the SPR of metal nanoparticles to reduce the surface reflectivity of the Si layer. At the same time, the absorption loss of Ag material in the blue-green light band is extremely low, thereby enhancing the absorption of the blue light band of the Si layer; for example, Cao et al. reported in Journal of Luminescence. 2022, 43(3), 396-403. Improve the PLQY and absorption efficiency of all-inorganic perovskite nanocrystal fluorescent solar concentrators by doping with appropriate concentrations of gold nanoparticles. The above schemes for improving absorption intensity through SPR are generally achieved by introducing metal nanostructures on the surface or inside the absorption layer. When applied to LSCs, it is usually necessary to add a scattering plate on the back of the collector to scatter the incident light back to the fluorescent layer, increase the optical path, and improve light absorption. However, the scattering plate makes the collector no longer transparent and cannot be integrated into buildings as photovoltaic windows. Therefore, metal nanostructures that can introduce SPR to enhance light absorption and scattering to increase the optical path length of incident light while ensuring a certain transmittance in the visible light band are of great significance for efficient LSCs that can be used in photovoltaic windows.

[0006] In addition to absorbing as much sunlight as possible, for LSCs, the fluorescence generated by the luminophore also needs to be transmitted to the photovoltaic unit through the waveguide as much as possible. However, it has not yet been widely used commercially, mainly due to the following two types of fluorescence loss mechanisms: one is the surface escape cone loss: part of the light emitted at a certain angle is refracted from the fluorescent layer into the air, instead of being transmitted to the photovoltaic unit on the side through total internal reflection in the waveguide. The cone surface formed by the exit path that is less than the total reflection angle is called the "escape cone"; the second is the reabsorption loss: this is because the photons emitted by the luminophore in the waveguide mode are reabsorbed by the subsequent luminophore during the transmission process without emitting new photons due to the overlap of the emission spectrum and the absorption spectrum of the luminescent group (limited by the Stokes shift).

[0007] To reduce the above losses, researchers are looking for effective solutions both inside and outside LSCs.

[0008] In response to the surface escape cone loss, researchers seek a photonic structure that meets the following requirements: the reflectivity is close to 1 in the fluorescence band of the luminescent material and has high transmittance in its absorption band. Band-stop reflective filters with the required optical properties have been found in photonic crystals. Distributed Bragg reflector (DBR), as a common one-dimensional photonic crystal, is usually composed of two layers of thin films with different refractive indices in multiple periods. It can increase the reflectivity of specific bands of the visible spectrum and show relatively low reflectivity in other bands. This high reflection band is the stop band. The stop band position and bandwidth can be changed by adjusting the central wavelength and the refractive index of the material to cover the fluorescence emission band of the luminescent material as much as possible and reduce the top fluorescence escape.

[0009] But for LSCs, ordinary DBR brings dense side lobes with high reflection intensity. If it is located in the absorption band of fluorescent materials, it will weaken the absorption to a certain extent, which is unacceptable. Since the side lobes are mainly caused by the refractive index mismatch between the material constituting the DBR and the air or the fluorescent layer, it is necessary to introduce a film layer with a gradient refractive index distribution between the DBR and the air and the fluorescent layer to reduce the side lobe intensity. However, the light confinement formed by the reflection of the side lobes of a certain reflection intensity and the waveguide structure at the bottom of the fluorescent layer may also excite the Fabry-Perot standing wave resonance with a low quality factor, which is beneficial to enhance the absorption of the incident light by the fluorescent layer, so comprehensive considerations need to be taken when designing the structure.

[0010] In order to effectively reduce reabsorption, in addition to increasing the Stokes shift of the fluorescent material from the perspective of material design, an intuitive and feasible structural design direction is to reduce the re-contact between the emitted fluorescent photons and the luminophore. As reported by Opt. Express 2010, 18, A536., Tsoi et al. used an extended air waveguide to physically separate the fluorescent thin layer. When the fluorescent photons are transmitted by total internal reflection in the glass waveguide above, the probability of meeting other dye molecules again is greatly reduced. However, as expected, the reduction in total light absorption caused by the physical gap between the absorption regions reduces the output of the entire system.

[0011] In summary, if LSCs are to be widely used, the device structure design needs to be further optimized. Summary of the invention

[0012] The purpose of the present invention is to improve the performance of perovskite nanocrystal fluorescent solar concentrators and provide an effective composite micro-nano structure to enhance the absorption intensity of the fluorescent layer, reduce the surface escape cone loss and reabsorption loss of the fluorescence, and maintain a high transmittance of the overall structure, thereby improving the performance of the entire concentrator.

[0013] To achieve the above-mentioned purpose, the technical solution of the present invention is: a perovskite nanocrystal fluorescent solar concentrator, comprising a fluorescent layer, a band-stop filter located on the top of the fluorescent layer, a silver nanowire array, i.e., an AgNW array, located on the bottom surface of the fluorescent layer, a coupling layer located below the fluorescent layer, and a bottommost glass substrate;

[0014] The fluorescent layer is composed of a transparent matrix and perovskite nanocrystals randomly and evenly distributed inside, the nanocrystal material is methylamine lead halide perovskite with absorption and photoluminescence properties, and the transparent matrix is ​​a common transparent polymer;

[0015] The reflection characteristic of the band-stop filter matches the fluorescence emission band of the perovskite nanocrystal, that is, the band-stop bandwidth of the band-stop filter covers the fluorescence emission band of the selected perovskite nanocrystal. More specifically, the average reflectivity of the band-stop filter in the fluorescence emission band of the perovskite nanocrystal needs to reach more than 90%; and the reflectivity range of the perovskite nanocrystal absorption band is 5%-20%;

[0016] The AgNW array is arranged horizontally and in parallel on the bottom surface of the fluorescent layer, and the diameter of a single AgNW and the duty cycle of the AgNW array satisfy the average reflectivity range of 30%-40% in the main absorption band of the perovskite nanocrystal;

[0017] The coupling layer is located between the AgNW array and the glass substrate, and is made of a common isotropic optical glass material with high transmittance. Its refractive index and thickness are sufficient to effectively weaken the absorption of fluorescence by the silver nanowire array and effectively extract fluorescence to the glass substrate. Specifically, the refractive index of the coupling layer is in the range of 1.7-2.0, and the thickness is in the range of 50-210 nanometers.

[0018] Compared with the prior art, the band-stop filter of the present invention has lower reflection in the absorption band of perovskite nanocrystals, allowing most of the sunlight incident from the outside to enter the fluorescent layer and be absorbed by the nanocrystals; its stop band covers the fluorescent band, reflects the fluorescence emitted by the nanocrystals, effectively reduces the fluorescence leaked from the top, and greatly reduces the surface escape cone loss;

[0019] The light confinement between the AgNW array and the band-stop filter of the present invention will excite the Fabry-Perot standing wave resonance with a low quality factor, and the absorption of the incident light by the fluorescent layer is enhanced; the scattering effect and SPR effect introduced by the AgNW in the ultraviolet band are used to further enhance the absorption of the fluorescent layer.

[0020] In addition, the high transparency of the AgNW array in the visible light band enables the entire light collector to maintain a high transmittance, and the average transmittance of the remaining visible light bands outside the stop band of the band-stop filter is higher than 0.7, which has the application prospect of photovoltaic windows;

[0021] The coupling layer involved in the present invention acts as an anti-reflection layer, weakens the sub-resonance absorption peak formed by AgNW in the fluorescence band, reduces the absorption of fluorescence by AgNW, extracts more fluorescent photons to the underlying glass substrate, effectively reduces the probability of fluorescent photons continuing to propagate in the fluorescent layer and being absorbed by subsequent luminophores, and effectively suppresses the reabsorption of the perovskite nanocrystal fluorescent layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the structure of a perovskite nanocrystal fluorescent solar collector according to the present invention;

[0023] Figure 2 Schematic diagram of the refractive index distribution of each layer of the band-stop filter in Examples 1, 2 and 3;

[0024] Figure 3 Schematic diagram of the reflection characteristic of the band-stop filter and the emission characteristic curve of the perovskite nanocrystal in Examples 1, 2 and 3;

[0025] Figure 4 The following is a performance parameter comparison table of Examples 1, 2, 3 and a reference device containing only a fluorescent layer and a glass substrate.

[0026] Among them, 1: perovskite nanocrystal-based fluorescent layer; 10: perovskite nanocrystal; 11: polymer matrix; 2: glass substrate; 3: band-stop filter; 4: silver nanowire; 5: coupling layer. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is described in detail below with reference to the accompanying drawings and specific implementation methods.

[0028] As attached Figure 1 As shown, it is a preferred embodiment of the perovskite nanocrystal fluorescent solar collector of the present invention, the collector comprises: a perovskite nanocrystal fluorescent layer 1, a glass substrate 2, a band-stop filter 3 on the top of the fluorescent layer, a silver nanowire (AgNW) array 4 horizontally arranged on the bottom surface of the fluorescent layer, and a coupling layer 5 between the fluorescent layer and the glass substrate layer, wherein the fluorescent layer comprises perovskite nanocrystals 10 and a transparent matrix 11;

[0029] The material of the perovskite nanocrystal 10 in the perovskite nanocrystal fluorescent layer 1 is methylamine lead halide perovskite, which includes but is not limited to methylamine lead chloride, methylamine lead bromide, and methylamine lead iodine, and the diameter of the nanocrystal particles ranges from 3 to 20 nanometers; the transparent matrix material is a transparent polymer material with a refractive index range of 1.4 to 1.6, and the transparent polymer material includes but is not limited to polystyrene, polyvinylidene fluoride, and polymethyl methacrylate, and the thickness of the transparent matrix ranges from 0.5 to 2.0 microns; the nanocrystal particles are randomly and evenly distributed in the transparent matrix, with a density of 1000 to 10000 per cubic micron.

[0030] The band-stop filter 3 on the top of the fluorescent layer is formed by stacking multiple layers of thin films with different refractive indices. Figure 1 Only part of the thin film layers are shown. The refractive index of several layers of thin film materials close to the incident medium (air) and the output medium (fluorescent layer) is gradually distributed, and the middle layers are composed of two layers of thin films with high refractive index and low refractive index arranged continuously for multiple periods. The stop band position and bandwidth of the reflection characteristics of the band-stop filter 3 need to match the fluorescence emission band of the selected perovskite nanocrystal 10.

[0031] The AgNW array 4 is horizontally arranged on the bottom surface of the perovskite nanocrystal fluorescent layer 1, the diameter of a single AgNW is 40-60 nanometers, and the arrangement duty ratio is 0.2-0.3. In the following preferred embodiment, the AgNWs are arranged at equal intervals, and the period range is 200-300 nanometers.

[0032] The coupling layer 5 is located between the perovskite nanocrystal fluorescent layer 1 and the glass substrate 2, and is made of common isotropic optical glass materials with high light transmittance, including but not limited to yttrium oxide, gadolinium oxide, and scandium oxide, with a refractive index range of 1.7-2.0 and a thickness range of 50-210 nanometers.

[0033] In the following embodiments, the perovskite nanocrystal fluorescent layer 1 uses methylamine lead bromide as the particle material of the perovskite nanocrystal 10; polyvinylidene fluoride (PVDF) is selected as the material of the transparent matrix 11, and the refractive index of the transparent matrix 11 is 1.42. The diameter of the nanocrystal particles is 20 nanometers, and the density is 1000 per cubic micrometer.

[0034] In the following embodiments, the material of the perovskite nanocrystal 10, methylamine lead bromide, has a fluorescence emission band of 490-575 nanometers and a fluorescence emission peak of 525.828 nanometers.

[0035] In the following embodiment, the band-stop filter 3 on the top of the fluorescent layer is composed of 50 layers of multilayer thin films with different refractive indices. The refractive index of the material of each of the 15 layers of thin films close to the incident medium (air) and the exit medium (fluorescent layer) is gradually distributed, and the middle 20 layers are composed of two layers of thin films with a high refractive index material, namely tantalum pentoxide (Ta2O5) with a refractive index of 2.0 and a low refractive index material, namely silicon dioxide (SiO2) with a refractive index of 1.6, arranged continuously for 10 periods. The refractive index distribution of each layer of thin film material is shown in the attached figure. Figure 2 As shown in the figure, the central wavelength of the designed filter is 545 nanometers and the total thickness is 3913.4 nanometers. Figure 3 As shown, the stopband bandwidth range of the band-stop filter 3 is 500-600 nanometers, which basically completely covers the fluorescence emission band of the selected perovskite nanocrystal 10, and the average reflectivity of the stopband is above 95%, which will effectively block the fluorescence leakage from the top of the fluorescent layer and reduce the escape cone loss of the fluorescent surface; the reflectivity range in the absorption band of the selected perovskite nanocrystal 10 is 5%-20%, which meets the conditions for generating Fabry-Perot standing wave resonance with the AgNW array 4.

[0036] In the following embodiments, the glass substrate 2 is made of quartz glass with a refractive index of 1.5 and a thickness of 3 mm, which is the thickness of conventional building window glass.

[0037] Embodiment 1

[0038] In this embodiment, the thickness of the transparent matrix 11 of the perovskite nanocrystal fluorescent layer 1 is 0.5 micrometers.

[0039] In this embodiment, the AgNW array 4 is horizontally and parallelly arranged on the bottom surface of the perovskite nanocrystal fluorescent layer 1, the radius of a single AgNW is 25 nanometers, the horizontal distribution period is 250 nanometers, and the arrangement duty ratio is 0.2.

[0040] In this embodiment, the coupling layer 5 is made of yttrium oxide, has a refractive index of 1.85, and a thickness of 70 nanometers.

[0041] Embodiment 2

[0042] In this embodiment, the thickness of the transparent matrix 11 of the perovskite nanocrystal fluorescent layer 1 is 1.0 micrometer.

[0043] In this embodiment, the AgNW array 4 is horizontally and parallelly arranged on the bottom surface of the perovskite nanocrystal fluorescent layer 1, the radius of a single AgNW is 25 nanometers, the horizontal distribution period is 200 nanometers, and the arrangement duty ratio is 0.25.

[0044] In this embodiment, the coupling layer 5 is made of gadolinium oxide, has a refractive index of 1.8, and a thickness of 150 nanometers.

[0045] Embodiment 3

[0046] In this embodiment, the thickness of the transparent matrix 11 of the perovskite nanocrystal fluorescent layer 1 is 1.0 micrometer.

[0047] In this embodiment, the AgNW array 4 is horizontally and parallelly arranged on the bottom surface of the perovskite nanocrystal fluorescent layer 1, the radius of a single AgNW is 30 nanometers, the horizontal distribution period is 200 nanometers, and the arrangement duty ratio is 0.3.

[0048] In this embodiment, the coupling layer 5 is made of scandium oxide, has a refractive index of 1.9, and a thickness of 170 nanometers.

[0049] like Figure 4 The figure shows the performance parameter comparison of the first, second and third embodiments with the reference device containing only the fluorescent layer and the glass substrate. The FDTDSolutions (finite difference time domain method) software is used to build the structural model of the perovskite nanocrystal fluorescent solar collector to simulate the actual collector. By setting the simulation light source and electromagnetic field environment parameters, the software simulation is run to obtain the absorption intensity, reflectivity, transmittance, fluorescent light power and other performance parameters related to the collector.

[0050] Absorption intensity enhancement: Absorption intensity refers to the amplitude of change in the integral of the absorption curve of the perovskite nanocrystal fluorescent layer 1. Compared with the reference device containing only the fluorescent layer and the glass substrate, under the influence of the scattering effect and SPR effect introduced by the AgNW array and the Fabry-Perot standing wave resonance formed by the AgNW array and the band-stop filter, the absorption intensity enhancement amplitudes of the perovskite nanocrystal fluorescent layer 1 corresponding to Examples 1, 2, and 3 are all above 20%, and the absorption enhancement amplitude corresponding to Example 1 is the largest, which is 29.34%;

[0051] Reduction in top-emitted fluorescent light power: The top-emitted fluorescent light power refers to the reduction in the fluorescent light power emitted from the top of the entire light collector; the part of the fluorescent light emitted from the top of the device is regarded as the leaked fluorescent light, and its size reflects the degree of loss of the fluorescent light escaping from the surface. Compared with the reference device containing only a fluorescent layer and a glass substrate, under the stop-band effect of the band-stop filter, it is monitored that the top-emitted fluorescent light power of Examples 1, 2, and 3 has been reduced by more than 75%, which indicates that the surface escape cone loss has been effectively reduced;

[0052] Improvement of bottom-transmitted fluorescent light power: Bottom-transmitted fluorescent light power refers to the variation of the fluorescent light power transmitted to the glass substrate in the perovskite nanocrystal fluorescent solar concentrators made in Examples 1 to 3 at the fluorescence emission peak of 525.828nm of methylamine lead bromide perovskite nanocrystals. Compared with the reference device containing only a fluorescent layer and a glass substrate, the fluorescent light power monitored in the glass substrates of Examples 1, 2, and 3 has increased by more than 15%. Under the action of the coupling layer, the absorption of fluorescence by the AgNW array is reduced, and the fluorescent photons are extracted into the glass substrate for further transmission, which reduces the probability of the fluorescent photons continuing to propagate in the fluorescent layer and being absorbed by subsequent luminophores, and the reabsorption loss is effectively suppressed;

[0053] The average transmittance in the visible light band refers to the average transmittance of the overall structure described in the embodiment outside the stop band of the band-stop filter. Since the high-transmittance materials and structures with optimized parameters are selected to build the collector architecture, the transmittance of the entire collector in embodiments 1, 2, and 3 is above 0.7, ensuring its application prospects in photovoltaic windows in the construction field.

[0054] The above embodiments are only used to illustrate the present invention but not to limit the technical solutions described in the present invention. The understanding of this specification should be based on the technicians in the relevant technical field. Although this specification has described the present invention in detail with reference to the above embodiments, ordinary technicians in the field should understand that technicians in the relevant technical field can still modify or replace the present invention with equivalents, and all technical solutions and improvements that do not depart from the spirit and scope of the present invention should be covered within the scope of the claims of the present invention.

Claims

1. A perovskite nanocrystal fluorescent solar concentrator, characterized in that: The light collector includes a fluorescent layer, a band-stop filter located on the top of the fluorescent layer, a silver nanowire array located on the bottom surface of the fluorescent layer, a coupling layer located below the fluorescent layer and a bottommost glass substrate; The fluorescent layer is composed of a transparent matrix and perovskite nanocrystals randomly and evenly distributed inside, the nanocrystal material is methylamine lead halide perovskite, and the transparent matrix is ​​a transparent polymer material; The stopband bandwidth of the band-stop filter covers the fluorescence emission band of the selected perovskite nanocrystal, that is, the average reflectivity of the band-stop filter in the fluorescence emission band of the perovskite nanocrystal needs to reach more than 90% and the reflectivity range of the perovskite nanocrystal absorption band is 5%-20%; The silver nanowire array is arranged horizontally and in parallel on the bottom surface of the fluorescent layer, and the diameter of a single AgNW and the duty ratio of the silver nanowire array satisfy the average reflectivity range of 30%-40% in the main absorption band of the perovskite nanocrystal; The coupling layer is located between the silver nanowire array and the glass substrate. The material of the coupling layer is an isotropic optical glass material with high light transmittance. The refractive index of the coupling layer is in the range of 1.7-2.0, and the thickness is in the range of 50-210 nanometers.

2. A perovskite nanocrystal fluorescent solar concentrator as claimed in claim 1, characterized in that: The methylamine lead halide perovskite is any one of methylamine lead chloride, methylamine lead bromide or methylamine lead iodine.

3. The perovskite nanocrystal fluorescent solar concentrator according to claim 1, characterized in that: The transparent matrix material has a refractive index ranging from 1.4 to 1.

6.

4. The perovskite nanocrystal fluorescent solar concentrator according to claim 1, characterized in that: The transparent polymer material is any one of polystyrene, polyvinylidene fluoride and polymethyl methacrylate, and the thickness of the transparent matrix is ​​in the range of 0.5-2.0 microns.

5. The perovskite nanocrystal fluorescent solar concentrator according to claim 1, characterized in that: The diameter of the nanocrystalline particles ranges from 3 to 20 nanometers, and the nanocrystalline particles are randomly and evenly distributed in the transparent matrix with a density of 1000 to 10000 per cubic micrometer.

6. The perovskite nanocrystal fluorescent solar concentrator according to claim 1, characterized in that: The band-stop filter is formed by stacking multiple layers of thin films with different refractive indices. The refractive indices of several layers of thin film materials close to the incident medium and the output medium are gradually distributed, and the middle layers are composed of two layers of thin films with high and low refractive indices arranged continuously in multiple periods.

7. The perovskite nanocrystal fluorescent solar concentrator according to claim 1, characterized in that: The diameter of a single AgNW ranges from 40 to 60 nanometers, and the arrangement duty ratio is 0.2 to 0.

3.

8. A perovskite nanocrystal fluorescent solar concentrator as claimed in claim 7, characterized in that: The AgNWs are arranged at equal intervals with a period range of 200-300 nm.

9. The perovskite nanocrystal fluorescent solar concentrator according to claim 1, characterized in that: The coupling layer is made of any one of yttrium oxide, gadolinium oxide and scandium oxide.

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