光面晶体硅-陷光膜复合的吸光结构及特性研究

In order to improve the photoelectric conversion efficiency of the crystalline silicon cell, how to efficiently absorb the sunlight and enhance the photovoltaic effect is the key. The light trapping structure can be obtained directly by adopting the surface texturing of crystalline silicon, which can reduce the loss of sunlight reflection. However, this method produces the surface defects, thereby reducing the photovoltaic effect. Due to this problem, the composite cell models of the smooth crystalline silicon − light trapping film is proposed in the project. The photovoltaic effect cannot only be improved by using the smooth crystalline silicon, but the loss of sunlight reflection can be reduced by the optically functional architecture of light trapping film and the composite technology as well. With the combination of the theoretical analysis and the experiments, the research can be going on (1) the optically functional architecture on the surface of the light trapping film and the trapping mechanism, (2) the absorbance of the composite structure of the smooth crystalline silicon-light trapping film, (3) the photothermal and photoelectric conversion efficiency of composite cell, (4) the photothermal effect on the photoelectric characteristics of the composite structure. Based on the proposed composite absorption structure of the smooth crystalline silicon-light trapping film and its characteristic, the radiant energy of the sun can be delivered and converted in the cell with the composite structure. Meanwhile, the reflection loss of the smooth crystalline silicon battery can be significantly reduced and the photovoltaic effect for the texturing can be improved. Thus, the proposed approach provides evidences for the analysis and implementation of the solar battery with efficiently photoelectric conversion.

提高晶体硅电池光电转换效率，关键在于如何实现对太阳光的高效吸收和增强光生伏特效应。采用制绒技术在晶体硅表面直接加工出陷光结构，虽能够降低太阳光反射损失，但也会产生新的表面缺陷态而引起光生伏特效应下降。为此，项目组提出光面晶体硅-陷光膜复合的吸光结构模型，采用光面晶体硅可增强光生伏特效应，通过陷光膜的光功能结构及复合技术来减少光反射损失。运用理论分析并结合实验来研究：⑴陷光膜表面的光功能结构及陷光机理；⑵光面晶体硅-陷光膜复合结构光学体系的吸光率；⑶光面晶体硅-陷光膜复合结构电池的光热和光电转换机制；⑷光热效应对复合结构电池光电特性的影响。所创建光面晶体硅-陷光膜复合的吸光结构及其特性理论，为阐明太阳辐射能在复合结构电池内的传递和转换提供理论依据，可解决光面晶体硅电池高反射损失与绒面晶体硅电池低光生伏特效应问题，对指导高光电转换效率太阳能电池的研发提供重要理论基础和工程应用价值。

本项目分析晶体硅电池常规光功能织构制备遇到的瓶颈问题，提出了一种光面晶体硅-陷光膜复合吸光结构。首先创建了光线在三棱锥光功能织构膜外表面反射损失和内表面折射损失的数学模型，优化复合结构光功能织构膜的三棱锥侧面倾角；结合三棱锥织构膜的制备工艺，对该织构膜的结构参数进行优化设计。其次，研究了光功能织构膜凸三棱锥原始模芯的超精密切削，利用精密电铸工艺制备凹三棱锥织构的工作模具，采用UV压印工艺制备三棱锥光功能织构膜；并分析了制备精度对三棱锥织构膜光学性能的影响。此外，通过对比绒面单晶硅电池、光面单晶硅电池和光面晶体硅-陷光膜复合电池的光电特性，综合评价了光面晶体硅-陷光膜复合吸光结构的性能。. 本项目提出一种光面晶体硅-陷光膜复合吸光结构模型，创建光线在三棱锥光功能织构膜外表面反射损失和内表面折射损失的数学表达式。把三棱锥织构膜复合在光面晶体硅电池上，优化得出三棱锥的侧面倾角为56.5°时，复合结构的反射损失最低为4.6%。考虑三棱锥织构膜制备缺陷的影响，计算陷光膜-光面晶体硅复合结构的光学损失为5.75%。提出了将均匀系数用于量化表征绒面单晶硅电池金字塔织构的均匀性，并应用均匀系数优化单晶硅片的制绒工艺参数，获得绒面单晶硅电池光电转换效率最高为19.63%。把陷光膜复合在光生伏特效应最佳的光面单晶硅电池片上，得到光面晶体硅-陷光膜复合吸光结构电池的光电转换效率最高为20.68%，比最佳绒面单晶硅电池的光电转换效率提高了1.05%。. 所创建光面晶体硅-陷光膜复合的吸光结构及其特性理论，为阐明太阳辐射能在复合结构电池内的传递和转换提供理论基础，可解决光面晶体硅电池高反射损失与绒面晶体硅电池低光生伏特效应问题，对高光电转换效率复合结构的太阳能电池研发提供了重要理论依据和工程应用指导。