等离子体亚波长微结构的可控生长及其吸收增强性能研究

Plasmonic subwavelength microstructures become one of hot research topic in the solar field due to have the potential for improving the thin film solar cells and reducing their cost, because the strong light trapping and broadband absorption enhancement can reduce the physical thickness of the photovoltaic absorber layers while enhance the conversion efficiency. To date the challenge and difficult point is how to pattern the plasmonic subwavelength microstructures. In this project, we will focus on the low-cost fabrication of controllable plasmonic sub-wavelength microstructures and explore the absorption enhancement mechanism and effect on the conversion efficiency improvement for thin film solar cells. The strategies adopted are as follows: Inorganic sub-wavelength microstructure template is prepared by photosensitivity sol-gel and plasmonic sub-wavelength microstructures could be obtained by assembling the Ag, Au nanostructures reduced in liquid on the template. anisotropy growth of Ag, Au nanostructures could be realized by controlling template size and liquid reduction condition. Thereby, we could achieve plasmonic sub-wavelength microstructures with controllable surface topography. And their light absorption enhancement properties will be determined and studied. Based on all of these results, the relationship between the absorption enhancement properties and plasmonic subwavelength microstructures (such as period, size and surface topography) will be aslo generalized. And we believe our approach for improving the conversion efficiency of thin film solar cells could provide a new idea and frame of reference for the preparation novel plasmonic subwavelength microstructures. All the research above could establish a stable foundation for the development of low-cost thin film solar cells with high conversion efficiency. Therefore, there are important scientific significance and practical application value for the research projects on this theme.

等离子体亚波长微结构具有优异的"陷光"和宽带吸收增强效应，可有效提高薄膜太阳能电池的光电转换效率并降低其吸收层的物理厚度，成为新能源领域的研究热点。目前等离子体亚波长微结构的制备仍面临极大地挑战。本项目将重点研究一种新型低成本、人为可控的等离子体亚波长微结构的制备方法，并探索其吸收增强机制及对薄膜太阳能电池转换效率的影响。主要利用光感应膜法制备无机亚波长微结构，并以此为模板，采用还原法生长Ag、Au等贵金属纳米材料，通过自组装获得等离子体微结构。设计模板尺寸和还原条件，控制贵金属的各向异性生长，实现对等离子体微结构的人为调控，并对其吸收增强性能及影响因素进行分析。预计通过本项目研究，可揭示等离子体微结构的形貌特征对吸收增强性能的影响。为新型等离子体微结构的制备提供新思路，进而为低成本、高转换效率薄膜太阳能电池的发展和应用奠定基础。因此，具有重要的科学意义和应用价值。

周期性贵金属纳米材料微阵列以其独特的LSRP特性，在太阳能电池、高性能SERS衬底等领域掀起了一股研究热潮，然而，如何制备大面积、高质量的贵金属纳米材料微阵列却仍面临极大的挑战。因此本项目的主要内容是发展一种新的贵金属纳米微阵列的制备方法----感光溶胶-凝胶结合化学还原自组装的方法，即采用感光溶胶-凝胶法制备图形模板，然后通过化学还原和自组装获得贵金属纳米材料微阵列。.利用感光溶胶-凝胶法，通过化学修饰合成具有高光学分辨率的含金属离子（Ti4+、Zr4+、Al3+、Si4+）配位化合物及其感光溶胶。结合紫外掩膜辐照技术及无掩膜激光干涉技术制备不同周期的一维、二维微阵列图形。并以此为模板，利用电化学还原自组装制备贵金属Au和Ag纳米材料微阵列。设计模板尺寸和还原条件，通过改变反应电压、电解液浓度、添加剂等因素调控贵金属纳米材料的形核及长大过程，实现对贵金属微结构形貌尺寸的人为调控。研究分析了所制备的贵金属纳米材料微阵列形貌对其LSRP及SERS特性的影响，获得了良好的实验结果，可明显探测到浓度低至10-13M R6G探针分子的拉曼信号。这些研究结果揭示了贵金属微阵列作为表面等离子激元增强拉曼衬底的潜在应用价值。同时，首次研究报道了贵金属Ag纳米颗粒对KYF4: Tb3+, Yb3+量子剪裁发光的表面波等离子体增强效应，这对于提高Si-基太阳能电池的转换效率具有十分重要的意义。