阅读说明：本技术 一种基于负折射率超材料的薄膜太阳能电池 (Thin-film solar cell based on negative refractive index metamaterial ) 是由 王霖 金尚忠 周碧颖 于 2019-04-03 设计创作，主要内容包括：本发明为一种基于负折射率超材料的薄膜太阳能电池。本发明通过渔网结构的负折射率超材料,改善薄膜太阳能电池对红外线和部分可见光谱的吸收,使得更多的光线到达太阳能电池表面,实现有效的光捕获和高的太阳能电池效率；该结构采用简单的蚀刻技术制造,其渔网结构周期性排布,从而具有大的宽带吸收。本发明渔网结构和薄膜太阳能电池组成的系统,在渔网结构的作用下,薄膜太阳能电池光吸收的带宽变大,提高了薄膜太阳能电池的效率。(The invention relates to a thin film solar cell based on a negative refractive index metamaterial. According to the invention, the thin-film solar cell can improve the absorption of infrared rays and part of visible spectrum by the negative refractive index metamaterial of the fishing net structure, so that more rays can reach the surface of the solar cell, and effective light capture and high solar cell efficiency can be realized; the structure is manufactured by adopting a simple etching technology, and the fishing net structures are periodically arranged, so that the structure has large broadband absorption. According to the system consisting of the fishing net structure and the thin-film solar cell, under the action of the fishing net structure, the light absorption bandwidth of the thin-film solar cell is increased, and the efficiency of the thin-film solar cell is improved.)

1. A thin-film solar cell based on a negative refractive index metamaterial is characterized in that the whole system is divided into a thin-film solar cell (1) and a fishing net structure (2); incident light rays in different directions reach the light receiving surface of the thin-film solar cell (1) through the fishing net structure (2).

2. The thin-film solar cell (1) is a cadmium telluride thin-film solar cell and consists of a glass substrate (6), a transparent conductive oxide layer (7), a cadmium sulfide window layer (8), a light absorption layer (9) and a metal electrode (11); the light absorbing layer (9) is made using a cadmium telluride photovoltaic material coated with a thin film of carbon nanotubes (10) on the surface of the cadmium telluride material.

3. The fishing net structure (2) is composed of a medium plate (4) in the middle, metal plates (3) and (5) on two sides of the medium plate and double connecting lines, wherein the metal plates on the two sides and the double connecting lines are completely the same and are a mixture of a cross and a circle.

4. The thin film solar cell based on the negative refractive index metamaterial according to claim 1, wherein: the glass substrate of the thin-film solar cell is a soda-lime glass covering layer, and the thickness of the cadmium sulfide window layer is 100-200 nm.

5. The thin film solar cell based on the negative refractive index metamaterial according to claim 1, wherein: the metal electrode deposited on the carbon nano tube film is a gold Au electrode or a nickel electrode.

6. The thin film solar cell based on the negative refractive index metamaterial according to claim 1, wherein: the thickness of the cadmium telluride photovoltaic material is 5-10 mu m, and the thickness of the carbon nanotube film covered on the surface of cadmium telluride is 50-100 nm.

7. The thin film solar cell based on the negative refractive index metamaterial according to claim 1, wherein: the size of the whole thin-film solar cell is (10-20) × (10-20) cm, the fishing net structure comprises (20-30) × (20-30) units, the thicknesses of the metal flat plates (3) (5) on two sides of the dielectric plate are 15-18 mu m, in a mixture of crosses and circles contained in each fishing net unit period, a = 5-10 mm, the thickness t = 750-800 mu m, the line width w = 1-2 mm of the crosses, and the circle radius R = 2-3 mm.

8. The thin film solar cell based on the negative refractive index metamaterial according to claim 1, wherein: the fishing net structure is manufactured by adopting an etching technology, the medium plate material in the middle is magnesium fluoride, and the metal materials on the two sides of the medium plate are gold.

Technical Field

The invention belongs to the technical field of solar cells, and particularly relates to a thin-film solar cell based on a negative-refractive-index metamaterial.

Background

The solar energy is utilized in a photo-thermal conversion mode and a photoelectric conversion mode, and solar power generation is a new renewable energy source. Solar energy is used as inexhaustible, clean and environment-friendly energy, has unprecedented development in recent years, and is expected to become the leading new energy of twenty-first century. The solar cell is a device which directly converts solar energy into electric energy by utilizing a photovoltaic effect, and the market mainstream is a crystalline silicon solar cell and a thin-film solar cell which are good and bad respectively; the thin-film solar cell is prepared on a cheap substrate, the material consumption and the cell cost are low, but the photoelectric conversion efficiency is still to be improved.

Cadmium telluride (CdTe) thin film solar cells have become the most competitive cell in the solar photovoltaic field, and the industrialized cell efficiency reaches more than 16%. However, it is still difficult to achieve higher conversion efficiency of the current cadmium telluride (CdTe) thin film solar cell, which limits the application of the cadmium telluride (CdTe) thin film solar cell to a certain extent. At present, the improvement of the conversion efficiency of the cadmium telluride thin film solar cell mainly aims at improving the utilization rate of sunlight in a short wave region and improving the utilization rate of sunlight in a near infrared region.

Negative refractive index metamaterials (NIMs) are artificially designed materials with negative dielectric constant and negative magnetic permeability, which have been a hotspot in research fields of electromagnetism, optics, materials and the like in recent years, and show a series of special properties which do not exist in natural materials, such as perfect lenses, negative refraction effect and the like. A negative index metamaterial refracts light on the same side perpendicular to the surface. When applied to a solar cell, more light may be absorbed rather than reflected by the solar cell. By designing the sub-wavelength structural unit and the size of the metamaterial, the magnetic resonance characteristic of the metamaterial can be regulated, and the metamaterial can generate a strong local field effect under the action of an electromagnetic field in a wavelength range and absorb more light.

Disclosure of Invention

Aiming at the problems in the prior art and the current research situation, the invention provides a thin-film solar cell based on a negative-refractive-index metamaterial.

In order to achieve the purpose, the invention adopts the technical scheme that: a thin-film solar cell based on a negative refractive index metamaterial is characterized in that the whole system is divided into a thin-film solar cell (1) and a fishing net structure (2); incident light rays in different directions reach the light receiving surface of the thin-film solar cell (1) through the fishing net structure (2). The thin-film solar cell (1) is a cadmium telluride thin-film solar cell and consists of a glass substrate (6), a transparent conductive oxide layer (7), a cadmium sulfide window layer (8), a light absorption layer (9) and a metal electrode (11); the light absorbing layer (9) is made using a cadmium telluride photovoltaic material coated with a thin film of carbon nanotubes (10) on the surface of the cadmium telluride material. The fishing net structure (2) is composed of a medium plate (4) in the middle, metal plates (3) and (5) on two sides of the medium plate and double connecting lines, wherein the metal plates on the two sides and the double connecting lines are completely the same and are a mixture of a cross and a circle.

The thin film solar cell based on the negative refractive index metamaterial is characterized in that: the glass substrate of the thin-film solar cell is a soda-lime glass covering layer, and the thickness of the cadmium sulfide window layer is 100-200 nm.

The thin film solar cell based on the negative refractive index metamaterial is characterized in that: the metal electrode deposited on the carbon nano tube film is a gold Au electrode or a nickel electrode.

The thin film solar cell based on the negative refractive index metamaterial is characterized in that: the thickness of the cadmium telluride photovoltaic material is 5-10 mu m, and the thickness of the carbon nanotube film covered on the surface of cadmium telluride is 50-100 nm.

The thin film solar cell based on the negative refractive index metamaterial is characterized in that: the size of the whole thin-film solar cell is (10-20) × (10-20) cm, the fishing net structure comprises (20-30) × (20-30) units, the thicknesses of the metal flat plates (3) (5) on two sides of the dielectric plate are 15-18 mu m, in a mixture of crosses and circles contained in each fishing net unit period, a = 5-10 mm, the thickness t = 750-800 mu m, the line width w = 1-2 mm of the crosses, and the circle radius R = 2-3 mm.

The thin film solar cell based on the negative refractive index metamaterial is characterized in that: the fishing net structure is manufactured by adopting an etching technology, the medium plate material in the middle is magnesium fluoride, and the metal materials on the two sides of the medium plate are gold.

The absorption principle of the fishing net structure is as follows: the fishing net structure unit generates magnetic resonance with incident electromagnetic waves, the fishing net unit generates strong coupling with the magnetic field of the incident electromagnetic waves, the metal substrate is coupled with the electric field of the incident electromagnetic fields, the whole fishing net structure and the free space form impedance matching, the reflectivity of the band where the magnetic resonance occurs is greatly reduced, the transmissivity is 0 due to the metal substrate on the back, and according to the sum of the absorptivity, the transmissivity and the reflectivity being 1, the frequency band where the magnetic resonance occurs at the fishing net unit can be deduced to realize high absorptivity, so that the thin-film solar cell made of the negative-refractive-index metamaterial can improve the absorption of infrared rays and part of visible spectrums, and the conversion efficiency is higher than that of a common cadmium telluride thin-film solar cell.

Compared with the prior art, the invention has the following beneficial effects.

1. The polycrystalline semiconductor material of cadmium telluride has the advantage of high chemical stability and the deposition process required to manufacture cadmium telluride thin film solar cells is simpler and less costly than silicon solar cells.

2. The specific fishing net structure on the surface of the cell can improve the absorption of infrared rays and partial visible spectrum, and achieves higher conversion efficiency than a common cadmium telluride thin film solar cell.

3. The carbon nano tube has good thermal stability, so that the efficiency of the battery is not reduced as the battery is doped with copper and Cu to be used as a back electrode, and the service life of the battery can be prolonged; the carbon nano tube film is prepared by the spin coating method, the preparation method is simple, and the cost is low.

Drawings

Fig. 1 is a general schematic diagram of a solar cell of the present invention.

Fig. 2 is a schematic view of the overall structure of the present invention.

FIG. 3 is a schematic view of the fishing net structure of the present invention.

Detailed Description

The invention is further described with reference to the following figures and specific embodiments.

As shown in figure 2, the thin-film solar cell based on the negative refractive index metamaterial is divided into a thin-film solar cell (1) and a fishing net structure (2). Incident light rays in different directions reach the light receiving surface of the thin-film solar cell (1) through the fishing net structure (2). The thin-film solar cell (1) is a cadmium telluride thin-film solar cell, and a cover plate structure and a heterodyne junction structure are adopted in the cadmium telluride thin-film solar cell; the solar cell comprises a soda-lime glass covering layer (6) serving as a supporting material, a transparent conductive oxide layer (7), a cadmium sulfide window layer (8) with the thickness of 100-200 nm, a light absorption layer (9) and a metal electrode (11). The light absorbing layer is fabricated using a cadmium telluride photovoltaic material that is coated with a thin film of carbon nanotubes (10) on the surface of the cadmium telluride material. The thickness of the cadmium telluride photovoltaic material is 5-10 mu m, and the thickness of the carbon nanotube film covered on the surface of cadmium telluride is 50-100 nm. The fishing net structure (2) is suitable for any linear polarization and consists of a medium plate (10) in the middle, metal flat plates (9) and (11) on two sides of the medium plate and double connecting lines, wherein the metal flat plates and the double connecting lines on the two sides are completely the same and are a mixture of a cross and a circle; the middle dielectric plate is made of magnesium fluoride, and the metal materials on the two sides of the dielectric plate are made of gold. The thickness of the metal flat plates (3) and (5) on two sides of the dielectric plate is 15-18 mu m, the fishing net structure comprises (20-30) units and (20-30) units, and the size of the whole thin-film solar cell is (10-20) cm and (10-20) cm.

As shown in fig. 3, the structure of the fishing net is schematically shown. The structure may be fabricated using etching techniques; in the mixture of the cross and the circle contained in each fishing net unit period, a (period) = 5-10 mm, the thickness t = 750-800 mu m, the line width w of the cross = 1-2 mm, and the radius R of the circle = 2-3 mm. The fishing net structures are periodically arranged, so that the current density on the structures is very high, high magnetic resonance is generated, the bandwidth of the high negative refractive index metamaterial is realized, and the negative refractive index is about 1. This particular fishing net structure on the thin film solar cell can improve the absorption of infrared and part of the visible spectrum, helping the solar cell achieve more efficient light capture and higher efficiency.

The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are merely exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.