Effect of the band alignment on the performance of heterojunction p-i-n solar cell is investigated in the framework of one-dimensional transport model. An affinity-based approach is introduced in order to identify a set of material parameters and doping levels which would result in lower series resistance $R_s$, higher open-circuit voltage $V_{{\rm oc}}$, and higher fill factor $FF$. The search reveals key ingredients of the nongraded heterojunction optimized design, whose efficiency can be as high as 27$ \% $. On one hand, certain band alignment determined by affinity-related quantities has to be observed to ensure the case of staggered gaps, once the dimensional requirements in the absorber and in the charge collectors are met. On the other hand, an affinity-based constraint is shown to control the potential profile which mitigates the adverse effect of barriers and accumulation regions at the junction interfaces. The constraint is shown to result in lower $R_s$ and, thus, higher $FF$. Analytical approach reveals a whole region in the affinity space where the reverse saturation current $J_0$ is at minimum, which also strongly overlaps with the constraints pinning down $R_s$. It is concluded that the performance figures are featured with shallow minima as functionals in roughly same region of the affinity space, where those numbers are relatively stable versus changes in the band alignment. The findings aim to make material screening more feasible and widens significantly the options in the design of new p-i-n cells.

中文翻译：

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亲和不连续性对异质结pin太阳能电池性能的影响

在一维输运模型的框架内研究了能带排列对异质结pin太阳能电池性能的影响。引入了一种基于亲和力的方法，以确定一组材料参数和掺杂水平，这将导致较低的串联电阻$R_s$, 较高的开路电压 $V_{{\rm oc}}$, 和更高的填充因子 $FF$. 搜索揭示了非梯度异质结优化设计的关键因素，其效率可高达 27$ \% $. 一方面，一旦满足吸收器和电荷收集器中的尺寸要求，就必须观察由亲和相关量确定的某些带排列以确保交错间隙的情况。另一方面，显示了基于亲和力的约束来控制电位分布，从而减轻结界面处势垒和积累区域的不利影响。显示约束导致较低$R_s$ 因此，更高 $FF$. 分析方法揭示了亲和力空间中反向饱和电流的整个区域$J_0$ 是最低限度，这也与约束约束强烈重叠 $R_s$. 得出的结论是，性能数据在亲和空间的大致相同区域中具有浅最小值作为泛函的特征，其中这些数字相对于带对齐的变化相对稳定。研究结果旨在使材料筛选更加可行，并显着拓宽设计新 pin 细胞的选择范围。