National Laboratory of Solid State Microstructures/School of Electronics Science and Engineering, Nanjing University, 210093 Nanjing, People's Republic of China.
Nanotechnology. 2019 Jul 26;30(30):302001. doi: 10.1088/1361-6528/ab0e57. Epub 2019 Mar 8.
Three-dimensional (3D) construction of radial junction hydrogenated amorphous silicon (a-Si:H) thin film solar cells on standing silicon nanowires (SiNWs) is a promising strategy to maximize the light harvesting performance and improve the photocarrier collection in an optimized junction configuration. The unique light in-coupling and absorption behaviour in the antenna-like 3D photonic structures also necessitates a set of new theoretical models and simulation tools to design, predict and optimize the photovoltaic performance of radial junction solar cells, which can be rather different from planar junction solar cells. Recently, the performance of radial junction a-Si:H thin film solar cells has progressed steadily to a level comparable or even superior to that of their planar counterparts, with plenty of room for further improvement. This review will first address the growth strategy and critical parameter control of SiNWs produced via a plasma-assisted low-temperature vapour-liquid-solid procedure using low-melting-point metals as the catalyst. Then, the construction of high-performance radial junction thin film solar cells over the standing SiNW matrix, as well as their optimal structural designs, will be introduced. At the end, the new applications of 3D radial junction units will be summarized, which include, for example, the construction of very flexible, low-cost and efficient a-Si:H solar cells with the highest power-to-weight ratio, the demonstration of highly sensitive solar-blind photodetectors operating at the ultraviolet wavelength spectrum and the development of novel biomimetic radial tandem junction photodetectors with an intrinsic red-green-blue (RGB) colour distinguishing capability.
三维（3D）构建直立硅纳米线（SiNWs）上的氢化非晶硅（a-Si:H）薄膜太阳能电池的径向结是一种很有前途的策略，可以最大限度地提高光捕获性能，并在优化的结结构中改善光生载流子收集。在类似天线的 3D 光子结构中的独特的光耦合和吸收行为也需要一组新的理论模型和模拟工具来设计、预测和优化径向结太阳能电池的光伏性能，这可能与平面结太阳能电池有很大的不同。最近，径向结 a-Si:H 薄膜太阳能电池的性能稳步发展，达到了与平面结太阳能电池相当甚至更高的水平，还有很大的改进空间。这篇综述将首先介绍使用低熔点金属作为催化剂通过等离子体辅助低温汽液固法生长 SiNWs 的生长策略和关键参数控制。然后，将介绍在直立 SiNW 基体上构建高性能的径向结薄膜太阳能电池及其最佳结构设计。最后，将总结 3D 径向结单元的新应用，例如，构建具有最高功率重量比的非常灵活、低成本和高效的 a-Si:H 太阳能电池，展示在紫外线光谱下工作的高灵敏度太阳能盲光电探测器，以及开发具有内在红-绿-蓝（RGB）颜色区分能力的新型仿生径向串联结光电探测器。
