缓冲层对p-a-Si/n-c-Si异质结太阳电池影响的计算分析

Analysis of the influence of buffer layer on p-a-Si/n-c-Si heterojunction solar cells

采用AFORS-HET和MATLAB从理论上研究了缓冲层对HIT电池性能的影响机理.首先对P层进行优化,发现高掺杂、薄厚度的P层有利于电池效率的提升.缓冲层主要的影响有两方面,一是界面态密度,二是与晶体硅形成能带失配.模拟发现,界面态增大导致复合中心密度上升,开路电压下降;能带失配的增大可以降低界面处少子浓度,起到场钝化效果,提高开路电压.短路电流和填充因子受到界面处的影响较小,与P层的工艺条件有比较大的关系.

The influence mechanism of buffer layer on HIT solar cells is researched by AFORS-HET and MATLAB. First, P layer’s condition is optimized, result shows that high doping, thin thickness P layer should be chosen. Buffer layer have a twofold effect, the influence on density of interface state, and the energy band offsets between with crystalline silicon. Through calculation and simulation with AFORS-HET and MATLAB, it is found that when the density of interface state increases, the density of recombination center would increase, then open circuit voltage decreases. When the band mismatch increases, the interface minority carrier concentration would decline, open circuit voltage then improves. The influence of buffer layer on short circuit current and fill factor is small, but P layer’s condition has a relative bigger influence on them.