Composite micro-nano photon structure for enhancing absorption efficiency of solar cell and manufacturing method thereof

Abstract

The invention discloses a composite micro-nano photon structure for enhancing absorption efficiency of a thin film solar cell and a manufacturing method thereof. The thin film solar cell comprises a surface layer and a cell basic cell, and is characterized in that the surface layer is equipped with the composite micro-nano photon structure with light trapping property, wherein and the composite micro-nano photon structure sequentially comprises a micro-nano photon structure with an efficient light trapping function, a passivation layer for suppressing nonradiative recombination, and a nano-scale textured sub-wavelength broad-spectrum wide-angle antireflection layer; the micro-nano photon structure at least comprises a one-dimensional grating, a two-dimensional grating or a three-dimensional photonic crystal, and the etching shapes and etching depths of various gratings or photonic crystals meet the condition that the diffraction angle of a photon in the surface layer of the solar cell is greater than the corresponding critical angle of total reflection. In the invention, the micro-nano photon structure, the passivation layer and the sub-wavelength antireflection structure are sequentially prepared on the surface layer of the cell by means of transfer of the graphic template of the micro-nano photon structure so that the surface layer of the solar cell integrates functions such as light trapping, nonradiative loss suppression, broad-spectrum wide-angle antireflection and the like, thus the absorption efficiency of the thin film solar cell is improved, and the overall conversion efficiency of the thin film solar cell is further improved.

Description

technical field [0001] The invention relates to a surface structure of a thin-film solar cell, in particular to a composite micro-nano photon structure suitable for enhancing the absorption efficiency of the solar cell. Background technique [0002] The energy issue is one of the greatest challenges faced by countries all over the world in the 21st century. The main bottleneck restricting the large-scale application of solar cells is to improve efficiency and reduce costs. In general, the thinning of the battery is not only beneficial to reduce costs and save resources, but also has the advantages of being easy to bend and integrating with other substrates, which is an important direction for the development of solar cells. Thin-film Si cells already account for about 10-15% of the market today. Other thin-film batteries also occupy a certain market share with their unique advantages. [0003] However, in the process of solar cell thinning, in addition to the surface refl...

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Problems solved by technology

However, as the battery becomes thinner, the micron-scale texturing achieved by wet etching, dry etching, and other methods is no longer applicable, and this micron-scale texturing achieves efficient light trapping by increasing light scattering, thereby increasing The optical path achieves absorption enhancement. This method of trapping light through geometric optics does not have wavelength selectivity, and the light trapping effect is insufficient.

The surface sub-wavelength anti-reflection structure caused by nanoscale texturing can achieve effective anti-reflection in a wide-spectrum wide-angle range, greatly reducing the reflection loss of the battery surface, but its surface light trapping effect is limited. At the same time, due to the sub-wavelength The introduction of the structure makes its surface area increase sharply, which leads to the increase of surface non-radiative recombination loss. Therefore, the introduction of sub-wavelength structure surface without passivation in solar cells does little to improve the efficiency of the cell.

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