The Mechanism Of Butterfly Scales With High Absorptivity Of Light And Design Of Bionic Structures

Solar energy, a kind of clean, efficient, new energy, will never be failure, in modern times, oil, and coal grow failure day by day, resulting in the research and exploitation of solar cells attract more attention. However the cost of solar cells is high and its photoelectric conversion efficiency is very low currently. Therefore, how to improve the photoelectric conversion efficiency of solar cells and reduce manufacturing costs of solar cells become a hotpot, while the thin film is an effective way to solve the problems above, which represent the future direction of the PV industry.At present, it was used to reduce the light loss of cell surface to improve the absorption rate of thin film solar cells. A good rough structure was created on the surface of the solar cell can enhance the light trapping effect effectively, reduce the surface loss of light, so that more light incident into the cell interior, thereby enhance the absorption rate of solar cells. In this paper, butterfly scales were selected as the bionic object, the rough structure with a high rate of absorption of light was designed preliminary, which is expected be applied to thin film solar cells in the near future to increase the absorption rate of solar energy.Butterfly wing surface covered with a large number of scales, neat and orderly, with distribution of tiles on the roof. The surface scales have special physical structures, such as many vertical groove, which is cyclical and close-packed structure. After receiving external light, it produced reflection, refraction, interference, diffraction, scattering and other optical effects, reflecting the bright colors. Butterfly scales absorb the energy of sunlight that required to maintain movement.Three kinds of butterflies (cold mountains) and two kinds of typical coloration of butterfly species were sclected as the object of study. First obtaining the reflection spectral curve, through that we select the special butterfly species with lowest reflectivity, which with the highest rate of relative absorption.Butterfly scales with different absorption properties were prepared for the experiments of stereomicroscope, the scanning electronic microscope (SEM), and the transmission electronic microscope (TEM). The surface configuration and inner microstructure of the scales were observed, and the parameters and character were analyzed, and the three-dimensional structure models were established. The mechanism of the high absorptivity was analyzed using optics principle of the interaction of the microstructure and the interaction of light, it is the result of the multiple reflections of light, multilayer film interference, rough micro-surface scattering and diffraction, and several levels Optical interaction.One two-dimensional V-type structure and one three-dimensional pit-type structure were established, and by using FDTD Solutions software, analysis and simulation two structural models of light absorption. Simulation results show that the pit-type structure can be used to reduce the surface loss of light, let more light incident into the cell interior.