The performance of photovoltaic devices is hindered by the presence of barrier height at the interfaces as well as the presence of structural defects. CdTe solar cells, based on a CdS/CdTe heterojunction and CdCl₂ vapour treatment, exhibit high efficiency. In this work, we show that the use of a hole-blocking layer has a potential to further increase the efficiency of CdTe-based cells. As a case study, we have fabricated multi-juncton CdTe-based solar cells on both pristine- and textured-silicon substrates. Here we use an n-type zinc tin oxide (ZTO) thin film as the transparent conducting oxide (TCO) layer and an n-type hole-blocking layer of MoO₃ on a p-type CdTe:Cu absorber layer. In addition, we map the nanoscale barrier height at each interface, i.e. ZTO/MoO₃ and MoO₃/CdTe:Cu by Kelvin probe force microscopy (KPFM). We also investigate the real time photo-generated charge carrier dynamics across the heterojunctions using photo-KPFM which plays a major role in the cell efficiency. Quantitative analysis shows that barrier height between the interfaces decreases after light illumination. Based on these findings, we have fabricated solar cells on pristine- and textured-Si substrates and the maximum efficiency is found to be 8.2% for the textured-Si substrate. The present study demonstrates the fabrication of efficient hole-blocking CdTe-based solar cells and provides insights on how local barrier height affects their macroscopic performance.

界面处的势垒高度的存在以及结构缺陷的存在阻碍了光伏装置的性能。基于CdS / CdTe异质结和CdCl ₂蒸气处理的CdTe太阳能电池显示出高效率。在这项工作中，我们表明使用空穴阻挡层有潜力进一步提高CdTe基电池的效率。作为案例研究，我们在原始和纹理化硅衬底上都制造了基于多结CdTe的太阳能电池。在此，我们使用n型氧化锌锡（ZTO）薄膜作为透明导电氧化物（TCO）层，并在p上使用MoO ₃的n型空穴阻挡层型CdTe：Cu吸收层。此外，我们绘制了每个界面（即ZTO / MoO ₃和MoO _3）的纳米级势垒高度/ CdTe：Cu的开尔文探针力显微镜（KPFM）。我们还研究了使用光KPFM跨异质结的实时光生电荷载流子动力学，它在电池效率中起主要作用。定量分析表明，光照后界面之间的势垒高度减小。基于这些发现，我们在原始的和纹理化的Si衬底上制造了太阳能电池，发现纹理化Si衬底的最大效率为8.2％。本研究证明了基于CdTe的高效空穴阻挡太阳能电池的制造，并提供了有关局部势垒高度如何影响其宏观性能的见解。