有效提高薄膜硅太阳能电池光转换效率是清洁能源利用领域的一个重要问题。设计了一种以三角形一维衍射光栅为基础的薄膜硅太阳能电池的背部反射器结构,用以有效提高硅太阳能电池的光转换效率。利用时域有限差分(FDTD)法,从光栅结构形状、倾斜角度、光栅周期以及光栅间隔等4个方面分别研究了薄膜硅太阳能电池下表面的光反射率。结果表明,由等腰直角三角形组成的一维光栅结构的背反射能力最强,合理增大光栅周期也将有助于提高硅太阳能电池的背面光反射率。此外,研究还发现,对于间隔型一维衍射光栅结构,平面波入射光会在和光栅周期对应的波长处发生共振现象。利用该特性,一维衍射光栅结构还可作为一种波长选择器。

In the community of green energy utilization, it has been a key issue to effectively enhance the light conversion of thin film silicon solar cells. A rear surface reflector structure of thin film silicon solar cells based on triangular one-dimensional diffraction gratings is designed, which can effectively enhance the light utilization efficiency of the solar cells. With a variety of grating structure types, inclination angles, grating periods and grating separations, the light reflectance of the rear surface of thin film silicon solar cells are respectively studied via the finite difference time domain (FDTD) method. The results indicate that the one-dimensional grating structure consist of isosceles right triangles gives rise to an optimal rear surface reflectance, and the reasonable increase of the grating period can also enhance the light reflectance of rear surface of the silicon solar cells. Besides, the study in this work also shows that there appears a resonance peak in the reflectance curve when the light wavelength matches the grating period of the gratings. Based on this diffraction characteristics, the one-dimensional grating structures proposed in this work can also be utilized as a wavelength selector in future designs.