含无序子结构的长周期光栅薄膜太阳电池的陷光机理

Both periodic structure and disorder structure are of respective merits in enhancement of sunlight trapping in solar cells, so it is a significant research frontier how to combine them and learn from other’s strong points to offset one’s weakness. The project proposes to investigate light trapping behavior in a kind of thin-film solar cell with long period gratings which are composed of disorder sub-structures. We expect that by introducing sub-structure disorders into long period grating, the main merits of both periodic structures and disorder structures could be merged, and the light trapping efficiency of solar cell can be enhanced greatly. The main research content contains: ⑴ By using both the frequency domain and time domain methods, we try to find the mechanism that how guided-mode resonance and slow light in long period gratings composed of ordered sub-structures influence the trapping efficiency associated with polarization, spectra bandwidth and the incidence angles, and also to distinguish light field spatial distribution characteristics. ⑵ Taking consideration of sub-structure disorders in position, size and shape, by making comparisons in frequency domain, time domain and also spatial distribution, we try to study how the multiple scattering and optical Anderson localization work in disorder systems and to find how these features influence the trapping efficiency associated with polarization, spectra bandwidth and the incidence angle. ⑶ Introducing two long period gratings on both the surfaces of the thin-film active layer respectively, light trapping efficiency dependent on various structures parameters will be systematically studied and high light trapping efficiency thin-film solar cell will be designed. The study is expected to expand knowledge about light trapping by using both order structure and the disorder structure. It will also provide new ideas and theoretical support for the development of high performance thin-film solar cells, couplers, filters detectors and also light emitting diodes.

周期结构和无序结构在提高薄膜太阳电池陷光效率方面各存在优势，因此探索能融合两者优势的新方法就成了学术研究的一个前沿。本项目拟研究含子结构的长周期光栅薄膜的陷光机理，期望在长程有序光栅中，通过引入子结构缺陷而具有局部无序特征，从而获得优势互补，提高陷光效率。⑴采用频域和时域方法，研究子结构有序时的长周期光栅中导模谐振和慢光等特性在偏振、带宽和入射角等方面对陷光效率的影响规律，并发掘光场空域分布特征；⑵引入位置、大小和形状等子结构缺陷后，比较频域、时域和空域分布特征，探索多重散射和光局域化等无序特性的作用机理，研究陷光特性在偏振、带宽和入射角等方面的改变规律；⑶融合有序和无序结构优势，在薄膜两个表面引入合适的长周期光栅，从偏振、带宽和角度等方面综合提高陷光效率。本项目的开展不仅有望增强对有序和无序结构陷光机理的认识，还可为发展高效薄膜太阳电池、耦合器、滤波器、探测器和发光二极管等提供理论参考。

周期结构和无序结构在提高薄膜太阳电池陷光效率方面各存在优势，因此探索能融合两者优势的新方法就成了学术研究的一个前沿。本项目首先构建了研究长周期光栅光传输特性的理论研究平台；再采用频域和时域方法，研究了子结构有序时的一维光栅中导模谐振、慢光、偏振和带宽等方面的传输特性，设计出了紧凑的非对称光栅偏振光集成分束器；在此基础上探讨了一维光栅对薄膜电池陷光效率的影响规律，设计出了高陷光效率的非对称一维光栅薄膜太阳电池；随后，研究了子结构有序时的二维光栅中导模谐振、慢光、偏振和带宽等方面的传输特性，设计出了具有大完全光子带隙带宽的低折射率比光子晶体及慢光光纤和光学微腔；在此基础上探讨了二维光栅对太阳能电池陷光效率的影响规律，设计出了高陷光效率的二维螺旋光栅薄膜太阳电池；最后，通过引入旋转子结构缺陷后，采用频域、时域和空域方法多角度分析，探索了光局域化等无序特性对光传输的作用机理，研究了局部无序子结构在偏振、带宽和入射角以及结构稳定性等方面对陷光效率的改变规律，综合提高了薄膜太阳电池的陷光效率和性能。本项目的完成不仅增强了对有序和无序结构陷光机理的认识，还可为发展高效薄膜太阳电池、耦合器、滤波器、探测器和发光二极管等提供理论参考。