Color semi-transparent photovoltaic system based on asymmetric bionic electrodes

Abstract

The present invention discloses a color semi-transparent photovoltaic system based on an asymmetric bionic electrode, which relates to the field of electrode structures of photovoltaic devices. The photovoltaic module comprises, from bottom to top, a spectral selection resonant cavity electrode (Ag / WO3 / Ag composite structure, with a 25-35 nm Ag layer and a 60-110 nm WO3 layer), a hole transport layer, an active layer, an electron transport layer, and a bionic electrode. The bionic electrode comprises a transparent electrode ITO with micro-nano structures added thereon, and the micro-nano structures are disposed on the top of the transparent electrode ITO. The color semi-transparent photovoltaic system based on an asymmetric bionic electrode mentioned in this application realizes a high transmittance peak of visible light and a high absorption rate of near-infrared through the synergistic effect of resonant cavity interference enhancement and bionic light wave structure light trapping effect, and solves the technical bottleneck that it is difficult to synergistically improve the light transmittance and efficiency in the BIPV field under the condition of maintaining high color purity.

Description

Technical Field

[0001] The present invention relates to the field of solar cells, particularly to a colored semi-transparent photovoltaic system based on an asymmetric biomimetic electrode. Background Art

[0002] Balancing color selectivity and photoelectric conversion efficiency is crucial for the integration of colored semi-transparent photovoltaic modules with building facades, rooftop photovoltaics, and mobile devices. The traditional method of adding pigments to achieve color adjustment greatly affects the efficiency of solar cells. Most common optical structures, such as one-dimensional photonic crystal bandpasses, are usually relatively wide, making it impossible to achieve high-color-purity devices, and it is difficult to implement the process due to the complex structure.

[0003] By simply changing the resonance mode of the resonator structure, it can be used to fabricate a spectral selection resonator electrode with high color purity. Considering the low efficiency of such devices, the present invention proposes a colored semi-transparent photovoltaic system based on an asymmetric biomimetic electrode. Summary of the Invention

[0004] To solve the above problems, the present application proposes a colored semi-transparent photovoltaic system based on an asymmetric biomimetic electrode, specifically involving the innovation of the electrode structure of building integrated photovoltaic (BIPV) devices. The periodic grid structure inspired by butterfly scales is integrated on the device surface, that is, by using the surface biomimetic micro-nano structure, while not affecting the color selectivity of the colored semi-transparent photovoltaic module, the transmission peak and light utilization rate of the device are improved, so as to realize a more efficient color-tunable colored semi-transparent photovoltaic module.

[0005] In addition, because the micro-nano grid structure significantly reduces the light reflectivity at wavelengths near the infrared band, the present invention can also significantly improve the light utilization rate in the main light absorption wavelength range of most materials. The transmission spectrum in the entire visible light range is hardly affected. Therefore, the colored semi-transparent photovoltaic system based on an asymmetric biomimetic electrode proposed by the present invention can also be used to improve the efficiency of the surface of broadband semi-transparent devices.

[0006] The colored semi-transparent photovoltaic system based on an asymmetric biomimetic electrode involved in the present invention specifically includes the following:

[0007] The colored semi-transparent photovoltaic system based on an asymmetric biomimetic electrode includes, from bottom to top, a spectral selection resonator electrode, a hole transport layer, an active layer, an electron transport layer, and a biomimetic electrode;

[0008] The biomimetic electrode includes a transparent electrode ITO with a micro-nano structure added, and the micro-nano structure is disposed on the top of the transparent electrode ITO.

[0009] Preferably, the micro-nano structure is composed of a substrate and a grid. The grid is a cubic structure with hollowed upper and lower surfaces, and the middle positions corresponding to the upper and lower surfaces are also hollowed, thereby forming a square channel in the cubic structure;

[0010] The grid is disposed on the upper surface of the substrate. The micro-nano structure is periodically repeated, and the substrate and the grid form a light trapping structure.

[0011] Preferably, the spectral selection resonant cavity electrode material is an Ag layer - WO3 layer - Ag layer from top to bottom.

[0012] Preferably, the spectral selection resonant cavity electrode is a traditional resonant cavity structure;

[0013] In the spectral selection resonant cavity electrode, the thickness of Ag is 15 - 35 nm, and the variation range of the cavity medium is 60 - 110 nm. Different thicknesses of the 60 - 110 nm cavity medium result in different colors. For example, a device with a WO3 cavity of 60 nm transmits blue light, and a 110 nm one transmits red light. Color selection is achieved by controlling the cavity medium.

[0014] Preferably, the thickness of the transparent electrode ITO is 190 nm.

[0015] Preferably, the active layer material is CsSnCl3, and the thickness of CsSnCl3 is 195 nm;

[0016] The hole transport layer material is MoO3, and the thickness of MoO3 is 40 nm;

[0017] The electron transport layer material is SnO x ,SnO x is 70 nm.

[0018] Preferably, the color semi-transparent photovoltaic system based on the asymmetric bionic electrode receives the AM1.5G incident spectrum;

[0019] The incident spectrum first passes through the light trapping structure and then through the spectral selection resonant cavity electrode, causing the light of the target wavelength to undergo constructive interference and the light of other wavelengths to undergo destructive interference, resulting in a high-transmission peak narrow half-width high spectrum that varies from blue to red for the transmitted spectrum.

[0020] The length range of the substrate is 525 - 680 nm;

[0021] The width range of the substrate is 525 - 680 nm;

[0022] The height range of the substrate is 8 - 13 nm;

[0023] The length range of the grid is 525 - 600 nm;

[0024] The width range of the grid is 525 - 600 nm;

[0025] The height range of the grid is 50 - 150 nm;

[0026] The thickness range of the grid is 50 - 80 nm.

[0027] In summary, the color semi - transparent photovoltaic system based on the asymmetric bionic electrode mentioned in the present invention has the following advantages compared with the traditional technology:

[0028] 1. Improve the efficiency of the photovoltaic system by reducing reflection;

[0029] 2. Do not affect the color adjustment and peak transmittance of the photovoltaic system in the visible light range.

[0030] The technical method of the present invention will be further described in detail below through the drawings and embodiments. Brief Description of the Drawings

[0031] Figure 1 It is a CIE chromaticity comparison diagram of the color semi - transparent photovoltaic system (including the grid structure) based on the asymmetric bionic electrode of the present invention and the traditional resonant cavity electrode (not including the grid structure);

[0032] Figure 2 It is a schematic diagram of the color semi - transparent photovoltaic system based on the asymmetric bionic electrode of the present invention;

[0033] Figure 3 It is a side view of the color semi - transparent photovoltaic system based on the asymmetric bionic electrode of the present invention;

[0034] Figure 4 It is a top view of the color semi - transparent photovoltaic system based on the asymmetric bionic electrode of the present invention;

[0035] Figure 5 It is a schematic diagram of the color semi - transparent photovoltaic system based on the asymmetric bionic electrode of the present invention irradiated by the AM1.5G incident spectrum.

[0036] Reference Signs

[0037] 1. Spectral selection resonant cavity electrode; 2. Hole transport layer; 3. Active layer; 4. Electron transport layer; 5. Bionic electrode; 501. Transparent electrode ITO; 502. Micro - nano structure; 5021. Substrate; 5022. Grid. Detailed Embodiments

[0038] The technical method of the present invention will be further described below through the drawings and embodiments. It should be noted that: unless otherwise specifically stated, the relative arrangement, numerical expressions and values of the components and steps described in these embodiments do not limit the scope of the present application.

[0039] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way a limitation on the present application, its application, or use.

[0040] Technologies, systems, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the technologies, systems, and devices should be regarded as part of the specification.

[0041] In all the examples shown and discussed herein, any specific values should be construed as merely exemplary and not as a limitation. Thus, other examples of the exemplary embodiments may have different values.

[0042] Unless otherwise defined, the technical terms or scientific terms used in the present invention shall have the ordinary meanings understood by those of ordinary skill in the field to which the present invention pertains.

[0043] The present invention provides a color semi-transparent photovoltaic system based on an asymmetric biomimetic electrode, as Figure 2 shown, the color semi-transparent photovoltaic system based on the asymmetric biomimetic electrode comprises, from bottom to top, a spectral selection resonant cavity electrode 1, a hole transport layer 2, an active layer 3, an electron transport layer 4, and a biomimetic electrode 5;

[0044] The biomimetic electrode 5 includes a transparent electrode ITO501 with micro-nano structures added, and the micro-nano structures are disposed on the top of the transparent electrode ITO501.

[0045] The micro-nano structure 502 is composed of a substrate 5021 and a grid 5022. The grid 5022 is a cubic structure, and the upper and lower surfaces of the cubic structure are hollowed out, and the middle positions corresponding to the upper and lower surfaces are also hollowed out, thereby forming a square channel in the cubic structure;

[0046] The grid 5022 is disposed on the upper surface of the substrate 5021. The micro-nano structure 502 is a periodically repeating structure, and the substrate 5021 and the grid 5022 form a light trapping structure. The unit period structure is at least 750 - 850 nm. The length and width of the unit period structure are the length and width of the substrate 5021 plus the distance to the adjacent substrate 5021. That is, in one unit period structure, there will be an optical structure composed of the substrate 5021 and the grid 5022.

[0047] Further, the material of the spectral selection resonant cavity electrode 1 is an Ag layer - WO3 layer - Ag layer from top to bottom.

[0048] Further, the spectral selection resonant cavity electrode 1 is a traditional resonant cavity structure;

[0049] In the spectral selection resonant cavity electrode 1, the thickness of Ag is 15 - 35 nm, and the variation range of the cavity medium is 60 - 110 nm. The two layers of Ag have the same thickness. Here, only Ag and WO3 are used as examples, and the use of other metals and dielectric layers also falls within the protection scope of the present invention. The cavity media with different thicknesses have different colors. For example, a device with a WO3 cavity of 60 nm transmits blue light, and a 110 nm one transmits red light. Color selection is achieved by different thicknesses of the cavity medium.

[0050] Further, the thickness of the transparent electrode ITO501 is 190 nm.

[0051] In the subsequent embodiments, the simulation data are calculated based on ITO without considering the micro-nano grid 5022 (100 nm). It is 100 nm from the bottom of the ITO to the bottom of the micro-nano grid ITO, and 190 nm to the top of the micro-nano grid ITO.

[0052] The 100 nm of the transparent electrode ITO501 refers to 100 nm from the bottom of the transparent electrode ITO501 to the bottom of the grid 5022. Although the grid 5022 itself is also part of the ITO, generally, the thickness of the ITO does not consider the convex / concave surface optical structure, such as the convex grid 5022 used in the present invention.

[0053] Further, the material of the active layer 3 is CsSnCl3, and the thickness of CsSnCl3 is 195 nm;

[0054] The material of the hole transport layer 2 is MoO3, and the thickness of MoO3 is 40 nm;

[0055] The material of the electron transport layer 4 is SnO x ,SnO x is 70 nm.

[0056] Further, the color semi-transparent photovoltaic system based on the asymmetric bionic electrode receives the AM1.5G incident spectrum;

[0057] As Figure 5 shown, the incident spectrum first passes through the light trapping structure, and then through the spectral selection resonant cavity electrode 1, which makes the light of the target wavelength undergo constructive interference and the light of other wavelengths undergo destructive interference, so that the transmitted spectrum is a narrow half-width high spectrum with different high transmission peaks from blue to red. The target wavelength is the wavelength at which the device transmits visible light, and its relationship with the thickness of the cavity medium is shown in the following equation:

[0058] ;

[0059] In the equation is the phase difference generated by the interface reflection between the metal of the resonant cavity electrode (Ag is taken as an example in this article) and the cavity medium (WO3 is taken as an example in this article), is the phase difference caused by the optical path difference.

[0060] Further, the base 5021 has a length, width and height of 600 nm × 600 nm × 10 nm;

[0061] The grid 5022 has a length, width and height of 600 nm × 600 nm × 90 nm, and the wall thickness of the grid 5022 is 80 nm.

[0062] As Figure 1 shown, by adjusting the thickness of each layer, when the transparent electrode ITO501 is 100 nm, SnOx is 70 nm, CsSnCl3 is 195 nm, MoO3 is 40 nm, and both layers of silver constituting the microcavity are 35 nm, the spectral selective resonant cavity electrode 1 can achieve color tunability in the full visible light range by changing through the cavity medium in the range of 60 - 110 nm, without affecting the color selectivity brought by the traditional resonant cavity electrode. The CIE chromaticity system is a color space standard developed by the International Commission on Illumination in 1931. Figure 1 The CIE 1931 system shown can be used to calculate and express colors. In this application, the transmitted light chromaticity coordinates under CIE1931 are calculated by the following formula:

[0063] ;

[0064] ;

[0065] ;

[0066] ;

[0067] In the formula, XYZ are the tristimulus values representing the amounts of the three primary colors, K is the adjustment factor, is the transmitted spectral power distribution, is the color matching function.

[0068] From Figure 1 it can be seen that the color of the traditional electrode is adjustable, corresponding to Figure 1 showing that the points on the CIE are distributed in a circle along the edge. In this application, a grid is added on the traditional electrode, corresponding to Figure 1 showing that the points on the CIE are still distributed in a circle along the edge. At the same time, Figure 1 there are points in the shape of a star (selective electrode, traditional) and a circle (asymmetric biomimetic motor, this application). It can be seen that the two points almost coincide, which means that the asymmetric biomimetic motor does not affect color selection compared with the traditional selective electrode.

[0069] The color semi - transparent photovoltaic system based on the asymmetric biomimetic electrode receives the AM1.5G incident spectrum;

[0070] The incident spectrum first passes through the light-trapping structure and then through the spectral selection resonant cavity electrode 1 with a cavity medium of 60 - 110 nm, which causes constructive interference for light of specific wavelengths and destructive interference for light of other wavelengths, resulting in a transmission spectrum with different high-transmission peak narrow half-width high spectra ranging from blue to red.

[0071] On this basis, by adjusting the basic parameters of the bionic electrode structure, a transmission spectrum in the visible light range is obtained without being affected, while the structural parameters for increasing the absorption of invisible light are: a substrate 5021 with a length, width, and height of 600 nm × 600 nm × 10 nm and a grid 5022 with a length, width, and height of 600 nm × 600 nm × 90 nm and a thickness of 80 nm are added at the center of the periodic repetition unit structure of 800 nm × 800 nm, and the optimal comprehensive ratio is obtained when the unit period structure is 800 nm.

[0072] As Figure 3 and Figure 4 shown, the AM1.5G solar spectrum passes through the light-trapping structure formed by the grid 5022 and the substrate 5021, reducing the reflectivity near the wavelength of 800 nm and increasing the carrier generation rate in the underlying active layer 3. After passing through the battery, the transmission spectrum is changed by using the selective resonance mode.

[0073] In this embodiment, the simulation software uses Comsol multi-physics simulation, and the optical and electrical three-dimensional models are established for optoelectronic coupling solution.

[0074] The optical module calculates the carrier generation rate of a unit periodic structure at different wavelengths. Perfectly matched layers are set at the top and bottom of the model, and periodic boundary conditions are used for the longitudinal boundaries. The carrier generation rate after integrating over the wavelength is substituted into the electrical model to solve for the battery efficiency.

[0075] The present invention provides an asymmetric bionic electrode based on a grid structure, which customizes the resonance mode through the top spectral selection resonant cavity electrode 1, and at the same time realizes the purpose of improving the device efficiency and peak transmittance through the grid 5022 structure of the bottom transparent electrode.

[0076] As shown in Table 1 and Figure 1 shown, the asymmetric bionic electrode based on the grid structure of the present invention improves the efficiency of the photovoltaic system by reducing reflection, and does not affect the color adjustment and peak transmittance of the optical device in the visible light range. The grid structure of this application is used for any semi-transparent battery and basically does not affect the optical characteristics.

[0077] Table 1 Comparison of asymmetric bionic electrodes based on grid structure

[0078]

[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical method of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that they can still modify the technical method of the present invention or make equivalent substitutions, and these modifications or equivalent substitutions cannot make the modified technical method deviate from the spirit and scope of the technical method of the present invention.

Claims

1. A color semi-transparent photovoltaic system based on an asymmetric bionic electrode, characterized in that, The color semi-transparent photovoltaic system based on the asymmetric bionic electrode consists of a spectral selection resonant cavity electrode, a hole transport layer, an active layer, an electron transport layer, and a bionic electrode from bottom to top; The bionic electrode includes a transparent electrode ITO with micro-nano structures added, and the micro-nano structures are arranged on the top of the transparent electrode ITO; The micro-nano structures are composed of a substrate and a grid. The grid is a cubic structure with the upper and lower surfaces hollowed out, and the middle positions corresponding to the upper and lower surfaces are hollowed out, thereby forming a square channel in the cubic structure; The grid is arranged on the upper surface of the substrate, and the micro-nano structures are periodically repeated to form an array structure. The substrate and the grid form a light trapping structure; The spectral selection resonant cavity electrode material is an Ag layer - WO3 layer - Ag layer from top to bottom.

2. The color semi-transparent photovoltaic system based on the asymmetric bionic electrode according to claim 1, wherein The thickness of Ag in the spectral selection resonant cavity electrode is 15 - 35 nm, and the thickness variation range of the cavity medium is 60 - 110 nm.

3. The color semi-transparent photovoltaic system based on an asymmetric bionic electrode according to claim 1, characterized in that, The thickness of the transparent electrode ITO is 190 nm.

4. The color semi-transparent photovoltaic system based on the asymmetric bionic electrode according to claim 1, characterized in that, The active layer material is CsSnCl3, and the thickness of CsSnCl3 is 195 nm; The hole transport layer material is MoO3, and the thickness of MoO3 is 40 nm; The electron transport layer material is SnO x , SnO x with a thickness of 70 nm.

5. The color semi-transparent photovoltaic system based on an asymmetric bionic electrode according to claim 1, characterized in that The color semi-transparent photovoltaic system based on the asymmetric bionic electrode receives the AM1.5G incident spectrum; The incident spectrum first passes through the light trapping structure, and then through the spectral selection resonant cavity electrode, making the light of the target wavelength undergo constructive interference and the light of other wavelengths undergo destructive interference, so that the transmitted spectrum is a narrow half-width high spectrum with different high transmission peaks from blue to red.

6. The color semi-transparent photovoltaic system based on an asymmetric bionic electrode according to claim 1, characterized in that, The length range of the substrate is 525 - 680 nm; The width range of the substrate is 525 - 680 nm; The height range of the substrate is 8 - 13 nm; The length range of the grid is 525 - 600 nm; The width range of the grid is 525 - 600 nm; The height range of the grid is 50 - 150 nm; The thickness range of the grid is 50 - 80 nm.

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