Department of Chemistry, University of California, Santa Barbara, California 93106, USA.
Nat Nanotechnol. 2013 Apr;8(4):247-51. doi: 10.1038/nnano.2013.18. Epub 2013 Feb 24.
Solar conversion to electricity or to fuels based on electron-hole pair production in semiconductors is a highly evolved scientific and commercial enterprise. Recently, it has been posited that charge carriers either directly transferred from the plasmonic structure to a neighbouring semiconductor (such as TiO₂) or to a photocatalyst, or induced by energy transfer in a neighbouring medium, could augment photoconversion processes, potentially leading to an entire new paradigm in harvesting photons for practical use. The strong dependence of the wavelength at which the local surface plasmon can be excited on the nanostructure makes it possible, in principle, to design plasmonic devices that can harvest photons over the entire solar spectrum and beyond. So far, however, most such systems show rather small photocatalytic activity in the visible as compared with the ultraviolet. Here, we report an efficient, autonomous solar water-splitting device based on a gold nanorod array in which essentially all charge carriers involved in the oxidation and reduction steps arise from the hot electrons resulting from the excitation of surface plasmons in the nanostructured gold. Each nanorod functions without external wiring, producing 5 × 10(13) H₂ molecules per cm(2) per s under 1 sun illumination (AM 1.5 and 100 mW cm(-2)), with unprecedented long-term operational stability.
基于半导体中电子-空穴对产生的太阳能转化为电能或燃料，是一项高度成熟的科学和商业事业。最近有人提出，载流子要么直接从等离子体结构转移到邻近的半导体（如 TiO₂）或光催化剂，要么通过邻近介质中的能量转移而被诱导，从而可以增强光转化过程，可能为实际利用光子带来一个全新的范例。局部表面等离子体可以激发的波长强烈依赖于纳米结构，这使得在理论上有可能设计出可以在整个太阳光谱和超出太阳光谱范围吸收光子的等离子体器件。然而，到目前为止，与紫外线相比，大多数此类系统在可见光下的光催化活性都相当小。在这里，我们报告了一种基于金纳米棒阵列的高效、自主的太阳能水分解装置，其中参与氧化还原步骤的几乎所有载流子都来自纳米结构金中表面等离子体激发产生的热电子。每个纳米棒在没有外部布线的情况下工作，在 1 个太阳光照（AM 1.5 和 100 mW cm(-2))下，每平方厘米每秒产生 5×10(13)个 H₂分子，具有前所未有的长期运行稳定性。
