High symmetry nano-photonic quasi-crystals providing novel light management in silicon solar cells
High symmetry nano-photonic quasi-crystals providing novel light management in silicon solar cells
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DOI：
10.1016/j.nanoen.2021.105874
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发表时间：
2021-06
期刊：
影响因子：
17.6
通讯作者：
T. Mercier;Tasmiat Rahman;C. Krishnan;E. Khorani;P. Shaw;M. Pollard;S. Boden;P. Lagoudakis;
中科院分区：
文献类型：
--
作者：
T. Mercier;Tasmiat Rahman;C. Krishnan;E. Khorani;P. Shaw;M. Pollard;S. Boden;P. Lagoudakis;
降低表面反射损失对于下一代高效硅太阳能电池至关重要。表面纹理提供了一种可行的方法来减少整个太阳能带宽的损失。以前的研究集中在从表面突出的简单蛾眼硅柱阵列上。使用FDTD模拟方法，我们进行了系统的调查提供了复杂的半随机光子准晶体表面图案化的方法，其中阵列的空气孔蚀刻深入到太阳能电池表面的性能优势。与其他研究相比，我们仔细研究了晶格对称性的影响，系统地比较了简单的6重对称三角形光子晶体图案化的性能，12重对称光子准晶图案化和无限对称的2D Fibonacci图案化。我们优化了关键几何参数，如晶格间距、孔尺寸和蚀刻深度，以最大限度地提高每种晶格类型的光学性能。发现12重光子准晶格提供最佳的整体抗反射性能，对于1.5 μm的孔深度和300 nm的直径，提供8.3%的太阳能校正平均反射率，而裸硅太阳能电池表面为36.4%。最佳设计的实际可行性证明了制造的物理原型组成的阵列的纳米尺度的空气孔蚀刻到使用电子束光刻和ICP/RIE蚀刻制造的硅板的表面。FDTD模拟方法的收敛性研究，以及比较这些制造的设备上的光学测量进行验证。此外，与以前的研究相比，我们提供了一个深入的分析的物理机制，负责减少表面反射，确定参数空间，传统的高斯光学过程，如有效折射率，折射和菲涅尔反射占主导地位，与参数空间，其中亚波长光子晶体散射效应发挥主要作用。最后，我们对优化设计的电气性能进行了分析，以进一步验证真实的性能。考虑到电性能，我们确定，无限对称的2D斐波那契图案远远优于较低的对称性12倍和三角形排列。我们相信这是第一次深入研究硅太阳能电池中的2D Fibonacci图案。
Reduction of surface reflection loss is crucial for high efficiency next generation Si solar cells. Surface texturing provides a viable method to reduce loss over the full solar bandwidth. Previous studies have concentrated on simple moth-eye silicon pillar arrays protruding from the surface. Using FDTD simulation methods, we undertake a systematic investigation into performance benefits provided by complex semi-random photonic quasi-crystal surface patterning methodologies whereby arrays of air holes are etched deep into the solar cell surface. In contrast to other studies we carefully investigate the effect of lattice symmetry, systematically comparing performance of simple 6-fold symmetric triangular photonic crystal patterning to 12 fold symmetry photonic quasicrystal patterning and infinitely symmetric 2D Fibonacci patterning. We optimize key geometric parameters such as lattice pitch, hole size and etch depth to maximize optical performance for each lattice type. 12 fold photonic quasi crystal lattice is found to provide best overall anti-reflectance performance providing a solar-corrected average reflectance of 8.3% for a hole depth of 1.5 µm and 300 nm diameter, in comparison to 36.4% for a bare silicon solar cell surface. Practical feasibility of the optimal designs is demonstrated by fabrication of physical prototypes consisting of arrays of nm scale air-holes etched into the surface of a silicon slab fabricated Using e-beam lithography and ICP/RIE etching. FDTD Simulation methodology is validated by convergence studies as well as comparison to optical measurements on these fabricated devices. Furthermore, in contrast to previous studies we provide an in depth analysis of the physical mechanisms responsible for reduction in surface reflection, determining the parameter space where conventional Gaussian optical processes such as effective refractive index, refraction and Fresnel reflection dominate, vs parameter space where sub wavelength photonic crystal scattering effects play the main role. We finish up with an analysis of electrical performance for the optimal designs to further validate real world performance. Taking electrical performance into account we determine that infinite-symmetry 2D Fibonacci patterning far outperforms lower symmetry 12 fold and triangular arrangement. We believe that this is the first in depth investigation into 2D Fibonacci patterning in silicon solar cells.