MODELING THE EFFECT OF DIFFERENT TEXTURES ON THE OPTICAL PROPERTIES OF A SILICON-BASED SOLAR CELL IN PVLIGHT HOUSE

ABSTRACT

This paper analyzes the results obtained by modeling the optical properties of a silicon-based solar cell based on the angle at the base of the straight and inverted pyramidal textures formed on their surface on the PV LIGHT HOUSE online platform. According to the results obtained, when the angle at the base of the correct pyramidal texture is 73,12⁰, the silicon-based solar cell reaches its maximum absorption coefficient.

АННОТАЦИЯ

В данной работе анализируются результаты, полученные при моделировании оптических свойств солнечного элемента на основе кремния на основе угла в основании сформированных на их поверхности прямых и перевернутых пирамидальных текстур на онлайн-платформе PV LIGHT HOUSE. Согласно полученным результатам, когда угол в основании правильной пирамидальной текстуры составляет 73 12⁰, солнечный элемент на основе кремния достигает максимального коэффициента поглощения.

Keywords: texture, solar cell, silicon, pyramid, absorption coefficient.

Ключевые слова: текстура, солнечный элемент, кремний, пирамида, коэффициент поглощения.

Various textures are created on the surface of the sun's elements to reduce the reflection of light incident on them. [1] [2]. There are two different purposes for this. The first is to increase the incident light surface, the second is to increase the absorption [3] and reduce the reflection coefficient [4] by creating more refractions between the two textures. Silicon with orientation [111] is mainly used in the production of solar cells [5]. When the surface of this silicon is chemically treated with alkalis, straight pyramidal textures with a base angle of 54.7⁰ are formed on the surface [6] - [8]. In this chapter, the optical properties of a silicon-based solar cell coated with straight pyramidal textures with different base angles are studied using a Wafer Ray Tracer. Based on the theory of pure optics, it was found that the absorption coefficient of a silicon-based solar cell is maximal when it is covered with straight pyramidal textures with a surface angle of 73,12⁰ [9]. However, a complex study of a textured silicon-based solar cell using TCAD software found that the absorption coefficient reached a maximum value when covered with textures with a base angle of 72,04⁰ [10]. Figure 1 illustrates the dependence of the optical properties of a silicon-based solar cell covered by straight pyramids with a base angle of 54.7⁰ (a) and 73.12⁰ (b) on the wavelength of light. As the angle at the base of the pyramidal texture increases, the absorption coefficient of the solar element increases and the reflection coefficient decreases. When the base angle of the pyramid is 73,12⁰, the absorption coefficient in the range of 500-1000 nm of wavelength is close to 100%.

a                                                                 b

Figure 1. Dependence of the optical properties of a silicon-based solar cell covered by straight pyramids with a base angle of 54.7⁰ (a) and 73.12⁰ (b) on the wavelength of light.

The optimal value of the angle varied when studying the above optical laws and the dependence of the efficiency of the solar cell on the base angle of the straight pyramidal textures formed on the surface of the solar cell using TCAD modeling. This is because surface recombination is not taken into account when calculating efficiency based on the laws of optics. In addition to optical parameters, surface recombination is taken into account when modeling in TCAD. As the angle at the base of the pyramidal texture increases, so does the active surface on which the light falls. Hence, an increase in the active surface leads to an increase in surface recombination. Therefore, the value of the angle calculated in TCAD was 1,08⁰ less than the value calculated based on the laws of optics.

The textures formed on the surface of the solar cell are mainly divided into two types: straight pyramidal and inverted pyramidal textures. Figure 2 shows the photogeneration coefficient of a single-crystal silicon-based solar cell depending on the angle at the base of the straight pyramidal texture formed on the surface. When the angle at the base of a straight pyramid increases from 0⁰ to 30⁰, the photogeneration coefficient increases slightly by 4%. This is because the light falling between the pyramids is refracted once it falls on the planar surface. The only reason for the increase in the photogeneration coefficient here is the increase in the active illuminated surface. When the angle at the base of the pyramid increases from 30⁰ to 45⁰, the light no longer begins to test twice, not once. Therefore, the photogeneration coefficient increased sharply by 20%. Between 45⁰ and 54⁰, the light refracts twice between the two pyramids, 3 times between 55⁰ and 63⁰, and 4 times at angles above 70⁰. It breaks 4 times when it falls between the light-based pyramids with an angle of 70⁰ to 80⁰. Suppose that the photogeneration coefficient is a function of the angle at the base of the pyramid. So this function consists of curves. Therefore, it must have extremes. Based on this idea, a theoretical study found that the maximum absorption coefficient is reached when the angle based on the straight pyramidal texture formed on the surface of a silicon-based solar cell is 73,12⁰. It was also found that PVLIGHTHOUSE achieves maximum photogeneration coefficient at a pyramid-based angle of 73,12⁰ when modeling a straight pyramidal textured silicon-based solar cell with different base angles using the Wafer Ray Tracer module.

Figure 2. The dependence of the photogeneration coefficient of a single-crystalline silicon-based solar cell on the angle based on a straight pyramidal texture formed on the surface

Unlike straight pyramids, inverted pyramids are becoming more popular. Inverted pyramids are formed using H₂O₂, NH₄HF₂ and polyvinyl pyrollidone. Inverted pyramids are a good anti-reflective agent for thin silicon-based solar cells. Figure 3 shows the coefficient of photogenesis of a single-crystalline silicon-based solar cell depending on the angle at the base of the inverted pyramidal texture formed on the surface. When the angle at the base of the inverted pyramid changes from 0⁰ to 45⁰ g, the change in the photogeneration coefficient is almost exactly the same as that of a solar cell covered with a pyramidal texture, with only 45⁰-80⁰ differences.

Figure 3. Dependence of the photogeneration coefficient of a single-crystal silicon-based solar cell on the angle based on the inverted pyramidal texture formed on the surface

Above, the photogeneration coefficient of a silicon-based solar cell coated with a straight and inverted pyramidal texture was analyzed as a function of the pyramid-based angle. Table 1 shows the photogenesis coefficients of a silicon-based solar cell with straight and inverted pyramidal textures with different base angles on the surface. The photogeneration coefficient of the straight pyramidal textured solar cell was high at all angles except pyramid-based angles 54⁰ and 70⁰. As mentioned above, mainly in the experiment, pyramids with an angle of 54.7⁰ at the base can be formed by chemical feeding on the surface of a silicon-based solar cell. Therefore, in the experiment, the efficiency of the inverted pyramidal textured silicon-based solar cell is high.

Table 1.

The dependence of the absorption coefficient of a silicon-based solar cell on the angle at the base of the pyramidal textures formed on the surface

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