银纳米光栅增加晶体硅薄膜太阳能电池光吸收的研究

Absorption Enhancement of Crystalline Silicon Thin Film Solar Cell Using Nano Binary Silver Grating

为了提高晶体硅（c-Si）薄膜太阳能电池对光的俘获能力，提出了一种可以显著增强光吸收的电池结构，该结构由减反射层、有源层和背反射镜组成。基于有效折射率调制的基本原则和严格耦合波理论，通过数值计算与仿真讨论了不同结构层的光学特性，计算了减反射层的透射率、背反射镜的反射率和经过优化后的c-Si薄膜太阳能电池的吸收率。在AM1．5G（地表面上接受到的以48。入射的太阳光谱，包含漫反射）照射下，当入射角小于75°，有源层的厚度为20μm时，太阳能电池在400～850nm、850～1000nm、1000～1100nm波长范围内平均吸收率分别为85．7％、49％、14％，有效弥补了c—Si薄膜太阳能电池近红外波段吸收不足的缺陷。

In order to enhance light trapping in the crystalline silicon（c-Si）thin film solar cell, a cell structure that can significantly enhance light absorption is presented, which is composed of antireflection coatings, active layer, and back mirrors. Based on the basic principle of effective refractive index modulation and the rigorous coupled wave theory, optical properties of different layers are discussed through the numerical calculation and simulation, including the transmissivity of antireflection coatings, the reflectivity of back mirror, and the absorptance of the optimized c-Si thin film solar cell. Under the radiation of AM1.5G （solar spectrum including diffused reflection received at the earth surface with a 48° angle incidence） spectrum and for the c-Si thin film solar cell with 20μm thick active layer, incident wave with TM polarization, and incident angle less than 75°, the integrated absorptance reaches 85.7%0, 49%, and 14%, respectively when the wavelength ranging from 400 to 850 nm, 850 to 1000 nm, and 1000 to 1100 nm. It can effectively compensate for the shortage of near infrared absorptance in the crystalline silicon thin film solar cell.