In this work, we substituted Al doped CdS(CdS:Al) for CdS buffer layer of Cu₂ZnSn(S,Se)₄ (CZTSSe) solar cell to increase built-in field and decrease interface recombination, and studied influence of this substitution on power conversion efficiency (PCE) of CZTSSe solar cell. It is found that the PCE can be increased from 6.57% to 8.99% by substituting CdS:Al with Al doping concentration of 3.3 at% for CdS. The increased PCE is mainly attributed to increase in photogenerated current density (J_L) and decrease in reverse saturation current density (J₀). Mechanisms of increase in J_L and decrease in J₀ are suggested by analysis of influence of change of bandgap, transmission, electron density and lattice constants of CdS induced by Al doping on light intensity passing through CdS, built-in field and lattice mismatch of CZTSSe/CdS heterojunction. This strategy provides a rational design for optimizing the heterojunction of CZTSSe solar cells to achieve high efficiency.

在这项工作中，我们用Al掺杂的CdS(CdS:Al)代替Cu ₂ ZnSn(S,Se) ₄ (CZTSSe)太阳能电池的CdS缓冲层以增加内建场并减少界面复合，并研究了这种替代的影响。 CZTSSe太阳能电池的功率转换效率（PCE）。发现用掺杂浓度为 3.3 at% 的 CdS:Al 代替 CdS 可以将 PCE 从 6.57% 提高到 8.99%。PCE的增加主要归因于光生电流密度( J _L )的增加和反向饱和电流密度( J ₀ )的降低。J _L增加和J ₀减少的机制通过分析Al掺杂引起的CdS的带隙，透射率，电子密度和晶格常数的变化对通过CdS的光强度，CZTSSe / CdS异质结的内建场和晶格失配的影响进行了分析。该策略为优化CZTSSe太阳能电池的异质结以实现高效率提供了合理的设计。