Research Of Two-dimensional Optical Micro- Structures For Reflective Property And Its Application In Silicon Solar Cells

With the development of human society and the progress of science and technology, human dependence on energy is higher and higher. However, the current energy used by human is mostly fossil fuels such as coal, natural gas, oil and so on, which belong to non-renewable energy. It is estimated that the total consumption of the world’s energy by mid-century is expected to double than that at the beginning of this century, and fossil fuels will be exhausted. On the other hand, combustion of fossil fuels releases large amounts of greenhouse gases and other toxic gases which have serious damage on the ecological environment. Now, the energy crisis and solving the environmental pollution issues which are faced by the human society are worked on by all countries around the world. Solar cells are the device which can directly convert solar energy into electrical energy. Compared to the fossil energy, the advantages of solar energy (such as it is inexhaustible, has immense power, with clean and safe use and not affected by geographical location) make it the preferred alternative. As one of the best ways of solar energy utilization, the research and development, industrial manufacturing technology and market development of solar cells have become the major focus of fierce competition in the world especially in the developed countries.But due to the electrical and optical loss of the solar cells, the efficiency of photoelectric conversion is limited. The optical loss can be divided into cover loss, surface reflection loss and the loss of spectral effect. In order to improve the efficiency of photoelectric conversion of solar cells with the problem of surface reflection, this paper to reduce the surface reflection loss and expand the low reflective property in a perfect frequency range.The details are described as follows:1、The basic structure and working principle of silicon solar cells as well as the research background of the current anti-reflective layer are introduced. At the same time, the advantages and defects of traditional anti-reflection layer are discussed. For the status of the current micro-fabrication technology, the development and current situation of two-dimensional optical micro-institutional research are introduced. On this basis, the new method which is about the two-dimensional sub-wavelength optical microstructures applied to the surface of the silicon solar cells for anti-reflection in recent years is put forward. This provides the research background of this paper.2、The light transmission characteristics in media have been studied starting from classical electromagnetic theory-Maxwell equations. Based on the transmission characteristics of linearly polarized light in two-layer medium interfaces and multi-layer medium of simulation and theoretical analysis, it provides a theoretical basis for the design and optimization of the monolayer and multilayer anti-reflection film. In order to further reduce the reflection and enhance the transmission, the effective medium theory and Mie scattering theory have been introduced.3、According to the effective medium theory and Mie scattering theory, the light reflection characteristics of two-dimensional optical microstructures are studied. The materials, height, duty ratio and morphology in detail of the two-dimensional optical microstructures which are the factors of the light reflection characteristics are studied by controlling variables.4、Based on determining silicon as the anti-reflective materials of micro-structure on the silicon solar cells, the two-dimensional optical microstructures composed of square column silicon particles and spherical silica particles are simulated by using MEEP simulation software. Researches have shown that, in this paper, the excellent anti-reflective property of two-dimensional sub-wavelength optical microstructure surface is used to expand the ultra-low reflective property of silicon solar cells in a perfect frequency range, and thus it provides theoretical guidance for design and manufacturing of two-dimensional optical microstructures.