纳米硅(nc-Si:H )/晶体硅(c-Si)异质结太阳电池的数值模拟分析

运用美国宾州大学发展的AMPS程序模拟分析了n-型纳米硅（n+-nc-Si:H）/p-型晶体硅(p-c-Si)异质结太阳电池的光伏特性.分析表明，界面缺陷态是决定电池性能的关键因素，显著影响电池的开路电压（VOC）和填充因子（FF），而电池的光谱响应或短路电流密度（JSC）对缓冲层的厚度较为敏感.对不同能带补偿（bandgap offset）的情况所进行的模拟分析表明，随着ΔEc的增大，由于界面态所带来的开路电压和填充因子的减小逐渐被消除，当ΔEc达到05eV左右时界面态的影响几乎完全被掩盖.界面层的其他能带结构特征对器件性能的影响还有待进一步研究.最后计算得到了这种电池理想情况下（无界面态、有背面场、正背面反射率分别为0和1）的理论极限效率ηmax=3117% (AM15，100mW/cm2，040—110μm波段).

Numerical simulation of nc-Si:H/ c-Si heterojunction solar cells

AMPS simulator, which was developed by Pennsylvania State University, has been used to simulate photovoltaic performances of nc-Si:H/ c-Si solar cells. It is shown that interface states are essential factors prominently influencing open circuit voltages (VOC) and fill factors (FF) of these structured solar cells. Short circuit current density (JSC) or spectral response seems more sensitive to the thickness of intrinsic a-Si:H buffer layers inserted into n+-nc-Si:H layer and p-c-Si substrates. Impacts of bandgap offset on solar cell performances have also been analyzed. As ΔEC increases, degradation of VOC and FF owing to interface states are dramatically recovered. This implies that the interface state cannot merely be regarded as carrier recombination centres, and impacts of interfacial layer on devices need further investigation. Theoretical maximum efficiency of up to 3117%(AM15, 100mW/cm2, 040—11μm) has been obtained with BSF structure, idealized light-trapping effect(RF=0, RB=1) and no interface states.