光伏发电是太阳能利用的重要途径之一。提高单晶硅的光学吸收特性可以提高光伏利用效率,降低制造成本。采用时域有限差分法计算了具有竖直排列纳米孔阵列结构的单晶硅薄膜的光学特性,发现纳米孔阵列强化光学吸收的机理包括等效折射率减小、纳米尺度效应和电磁波谐振效应。计算结果表明,合理设计纳米孔阵列的排列周期和孔径可以大幅增强单晶硅薄膜的光学吸收,使纳米孔阵列单晶硅薄膜光伏器件的理论效率比相同厚度单晶硅片光伏器件高85.5%,并预期可以使10^0μm量级厚度的纳米孔结构单晶硅薄膜具有和10^2μm量级厚度的单晶硅片相当的光伏特性。
Photovoltaic is one of the most important methods to harvest solar energy.Enhancing the crystalline silicon optical absorption increases the photovoltaic efficiency and reduces the cost.The optical properties of vertically aligned silicon nanohole arrays using the Finite-Difference Time-Domain method.The absorption enhancement was found to be attributed to effective refractive index decrease,nanoscale effect and guided wave resonances.Results show that the optical absorption is enhanced by optimizing the periodicity and nanohole size and thus,the photovoltaic ultimate efficiency of the silicon nanohole array is 85.5% higher than the efficiency of the silicon wafer with the same thickness.The silicon nanohole array with 100μm thickness is expected to absorb as efficiently as the silicon wafer with 102μm thickness.