1] Department of Mechanical and Aerospace Engineering, West Virginia University, Morgantown, West Virginia 26506-6106, USA [2].
Nat Commun. 2013;4:2651. doi: 10.1038/ncomms3651.
Plasmonic metal nanostructures offer a promising route to improve the solar energy conversion efficiency of semiconductors. Here we show that incorporation of a hematite nanorod array into a plasmonic gold nanohole array pattern significantly improves the photoelectrochemical water splitting performance, leading to an approximately tenfold increase in the photocurrent at a bias of 0.23 V versus Ag|AgCl under simulated solar radiation. Plasmon-induced resonant energy transfer is responsible for enhancement at the energies below the band edge, whereas above the absorption band edge of hematite, the surface plasmon polariton launches a guided wave mode inside the nanorods, with the nanorods acting as miniature optic fibres, enhancing the light absorption. In addition, the intense local plasmonic field can suppress the charge recombination in the hematite nanorod photoanode in a photoelectrochemical cell. Our results may provide a general approach to overcome the low optical absorption and spectral utilization of thin semiconductor nanostructures, while further reducing charge recombination losses.
等离子体金属纳米结构为提高半导体的太阳能转换效率提供了一条有前景的途径。在这里，我们展示了将赤铁矿纳米棒阵列纳入等离子体金纳米孔阵列图案中，可显著提高光电化学水分解性能，在模拟太阳光辐射下，在相对于 Ag|AgCl 的 0.23 V 偏压下，光电流增加了近十倍。等离子体诱导的共振能量转移负责增强低于能带边缘的能量，而在赤铁矿的吸收带边缘以上，表面等离激元激发出纳米棒内的导波模式，纳米棒充当微型光纤，增强光吸收。此外，强局域等离子体场可以抑制光电化学电池中赤铁矿纳米棒光阳极中的电荷复合。我们的结果可能为克服薄半导体纳米结构的低光学吸收和光谱利用率提供一种通用方法，同时进一步降低电荷复合损失。
