Zhao Yongxiang, Chen Fei, Shen Qiang, Zhang Lianmeng
State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan, China.
Opt Express. 2012 May 7;20(10):11121-36. doi: 10.1364/OE.20.011121.
In this paper, a graded SiNx and SiOxNy structure is proposed as antireflection coatings deposited on top of amorphous silicon (α-Si) thin-film solar cell. The structural parameters are optimized by differential evolution in order to enhance the optical absorption of solar cells to the greatest degree. The optimal design result demonstrates that the nonlinear profile of dielectric constant is superior to the linear profile, and discrete multilayer graded antireflection coatings can outperform near continuously graded antireflection coatings. What's more, the electric field intensity distributions clearly demonstrate the proposed graded SiNx and SiOxNy structure can remarkably increase the magnitude of electric field of a-Si:H layer and hence, enhance the light trapping of a-Si:H thin-film solar cells in the whole visible and near-infrared spectrum. Finally, we have compared the optical absorption enhancements of proposed graded SiNx and SiOxNy structure with nanoparticles structure, and demonstrated that it can result in higher enhancements compared to the dielectric SiC and TiO2 nanoparticles. We have shown that the optimal graded SiNx and SiOxNy structure optimized by differential evolution can reach 33.31% enhancement which has exceeded the ideal limit of 32% of nanoparticles structure including plasmonic Ag nanoparticles, dielectric SiC and TiO2 nanoparticles.
本文提出了一种渐变的SiNx和SiOxNy结构作为沉积在非晶硅（α-Si）薄膜太阳能电池顶部的减反射涂层。通过差分进化对结构参数进行优化，以最大程度地提高太阳能电池的光吸收。优化设计结果表明，介电常数的非线性分布优于线性分布，离散多层渐变减反射涂层的性能优于近连续渐变减反射涂层。此外，电场强度分布清楚地表明，所提出的渐变SiNx和SiOxNy结构可以显著增加a-Si:H层的电场强度，从而增强a-Si:H薄膜太阳能电池在整个可见光和近红外光谱中的光捕获。最后，我们将所提出的渐变SiNx和SiOxNy结构与纳米颗粒结构的光吸收增强效果进行了比较，结果表明，与介电SiC和TiO2纳米颗粒相比，它可以实现更高的增强效果。我们已经表明，通过差分进化优化的最佳渐变SiNx和SiOxNy结构可以实现33.31%的增强，这已经超过了包括等离子体Ag纳米颗粒、介电SiC和TiO2纳米颗粒在内的纳米颗粒结构32%的理想极限。
