氧化锌/晶硅叠层太阳能电池紫外性能提升研究

Research on the Improvement of Ultraviolet Performance of ZnO/Si Tandem Solar Cell

摘要: 晶硅太阳能电池带隙与短波段光子的能量不匹配影响了其光电转化效率的提升。ZnO作为一种宽禁带半导体，其高透光率和与SiN_x接近的折射率有望替代SiN_x实现高效减反射，同时拓展硅太阳能电池的吸收光谱。本文通过Wafer Ray Trace软件对比了ZnO与SiN_x在硅片上的光学特性，结果显示ZnO/Si叠层结构因ZnO对紫外波段光子高吸收可拓宽硅太阳能电池的光响应范围至紫外波段。基于此，使用Silvaco软件在PERC太阳能电池基底上叠加了80 nm的ZnO，设计了一种ZnO/Si叠层太阳能电池，对其进行了深入的数值模拟和理论分析。具有80 nm SiN_x层的的p型PERC太阳能电池被用来进行性能对比。结果显示，ZnO/Si叠层太阳能电池具有优异的紫外光电转换效率。通过调整ZnO的关键参数，研究了ZnO/Si叠层太阳能电池性能的变化，深入探讨了影响ZnO层中光生载流子利用的因素与ZnO中光生载流子的传输机制，并对ZnO/Si叠层太阳能电池进行了优化。

Abstract: The mismatch between the bandgap of crystalline silicon and the energy of short-wavelength photons affects the improvement of its photoelectric conversion efficiency. As a wide-bandgap semiconductor, ZnO has high transmittance and a refractive index close to that of SiN_x, making it promising to replace SiN_x for efficient antireflection, and at the same time expanding the absorption spectrum of silicon solar cells. In this paper, the optical properties of ZnO and SiN_x on silicon wafers were compared using the Wafer Ray Trace software. The results show that due to the high absorption of ultraviolet photons by ZnO, the ZnO/Si tandem structure can broaden the optical response range of silicon solar cells to the ultraviolet band. Based on this, the Silvaco software was used to stack 80 nm of ZnO on the substrate of a PERC solar cell, and a ZnO/Si tandemsolar cell was designed, and in-depth numerical simulations and theoretical analyses were carried out. A p-type PERC solar cell with an 80 nm SiN_x layer was used for performance comparison. The results show that the ZnO/Si tandemsolar cell has excellent ultraviolet photoelectric conversion efficiency. By adjusting the key parameters of ZnO, the performance changes of the ZnO/Si tandem solar cell were studied, the factors affecting the utilization of photogenerated carriers in the ZnO layer and the transmission mechanism of photogenerated carriers in ZnO were discussed in depth, and the ZnO/Si tandemsolar cell was optimized.