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

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/MgF_(2)与TCO/SiO_(2)减反射结构,获得了最佳光生电流密度。通过热蒸发制备了MgF_(2)薄膜,射频磁控溅射制备了SiO_(2)薄膜,经过优化构建了具有高透过率(92.56%)的MgF_(2)/SiO_(2)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MgF_(2)/SiO_(2)叠层减反射结构,正面辅以单层SiO_(2)或MgF_(2)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/cm^(2)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。

In this paper,the photogenerated current density and absorbance of silicon heterojunction(SHJ)solar cells with different wafer thickness from 50μm to 200μm 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/MgF_(2)and TCO/SiO_(2)with different film thickness were simulated to obtain the best photogenerated current density.In experimental methods,MgF_(2)thin film was prepared by thermal evaporation and SiO_(2)thin film was deposited by RF magnetron sputtering.The MgF_(2)/SiO_(2)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 MgF_(2)/SiO_(2)AR structure was applied on the rear side of SHJ solar cell and single MgF_(2)or SiO_(2)film for front side.The short circuit current density(J)when illumination from rear side improved obviously above 1.10 mA/cm^(2)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.