95%高双面率异质结太阳电池的叠层减反射研究

Research on Double-layer Anti-reflection Structures of Silicon Heterojunction Solar Cells with 95% High Bifaciality

  • 摘要: 本文通过PV Lighthouse模拟了硅片厚度(从50μm至200μm)对晶硅异质结(SHJ)太阳电池的光学吸收及光生电流密度的影响,剖析了电池柔性化面临的瓶颈问题,并模拟了不同厚度的TCO/MgF2与TCO/SiO2减反射结构,获得了最佳光生电流密度。通过热蒸发制备了MgF2薄膜,射频磁控溅射制备了SiO2薄膜,经过优化构建了具有高透过率(92.56%)的MgF2/SiO2叠层减反射结构,将器件入光面反射率从6.70%降低至5.46%。在SHJ电池背面应用MgF2/SiO2叠层减反射结构,正面辅以单层SiO2或MgF2减反射薄膜,背面入光时的外部量子效率(EQE)显著提高了2.35%,使短路电流密度提升1.10 mA/cm2以上。该叠层减反射方案实现了95.16%的超高双面率,对提升双玻组件的发电量具有重要意义。

     

    Abstract: In this paper, the photogenerated current density and absorbance of silicon heterojunction(SHJ) solar cells with different wafer thickness from 50 μm to 200 μm were simulated by PV Lighthouse. It is found that the limitation of photogenerated current of flexible SHJ solar cells is caused by decreased substrate absorbance. Thus, the anti-reflection(AR) structures including TCO/MgF2 and TCO/SiO2 with different film thickness were simulated to obtain the best photogenerated current density. In experimental methods, MgF2 thin film was prepared by thermal evaporation and SiO2 thin film was deposited by RF magnetron sputtering. The MgF2/SiO2 AR structure with high transmittance(92.56%) was fabricated, which can reduce the reflectance of the SHJ substrate from 6.70% to 5.46%. In addition, the MgF2/SiO2 AR structure was applied on the rear side of SHJ solar cell and single MgF2 or SiO2 film for front side. The short circuit current density(JSC) when illumination from rear side improved obviously above 1.10 mA/cm2 due to the rear EQE was significantly increased by 2.35%. Moreover, the bifaciality of SHJ solar cell has been achieved 95.16% in this work, which is of great importance to enhance power generation of glass-glass photovoltaic modules.

     

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