Abstract Transport properties of photo-induced charge carriers through different grains in the polycrystalline photovoltaic devices strongly depend on the microstructural pattern of the active layers. Therefore, photocurrent mapping with nanoscale resolution is important to know about the electrical responses of the different grains in the polycrystalline photovoltaic devices. Here, we have used photoconductive atomic force microscopy for mapping the photocurrent with nanoscale resolution of two types of ZnO nanorods/Cu2O based solar cells. The morphology and current have been measured simultaneously with nanoscale resolution from the top surfaces of the devices at different applied voltages. It is demonstrated that the nanostructure of the active layers is one of the most important variables determining device performances. Different local photovoltaic performances have been observed from these two devices due to various microstructural and electrical phenomena of their seed layers. On the other hand, significant variations in short-circuit current have been observed from different grains of the devices which appeared more alike in the micrograph owing to various transport properties of photocarriers. It is observed that the grain boundaries are more preferable for charge collection over the grain interiors. It shows a higher short circuit current close to the boundary than the grain inside. This study illustrates an important area for future fundamental research to enhance the performances of the polycrystalline photovoltaic devices through better control of morphology and improving the inherent properties of the active layers.

中文翻译：

---

具有纳米级分辨率的氧化物基太阳能电池中的光感应电流映射

摘要 光致载流子通过多晶光伏器件中不同晶粒的传输特性在很大程度上取决于有源层的微观结构模式。因此，具有纳米级分辨率的光电流映射对于了解多晶光伏器件中不同晶粒的电响应非常重要。在这里，我们使用光电导原子力显微镜以纳米级分辨率绘制了两种类型的 ZnO 纳米棒/Cu2O 基太阳能电池的光电流。在不同施加电压下，从器件的顶面以纳米级分辨率同时测量形态和电流。结果表明，活性层​​的纳米结构是决定器件性能的最重要的变量之一。由于种子层的各种微观结构和电学现象，已经从这两种器件观察到不同的局部光伏性能。另一方面，由于光载流子的各种传输特性，从器件的不同晶粒中观察到短路电流的显着变化，在显微照片中看起来更相似。观察到晶界更优选用于在晶粒内部之上的电荷收集。它显示靠近边界的短路电流高于内部晶粒。这项研究说明了未来基础研究的一个重要领域，即通过更好地控制形态和改善有源层的固有特性来提高多晶光伏器件的性能。