Size Dependent Plasmonic Effect on BiVO4 Photoanodes for Solar Water Splitting.
Size Dependent Plasmonic Effect on BiVO4 Photoanodes for Solar Water Splitting.
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DOI：
10.1038/srep16660
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发表时间：
2015-11-19
影响因子：
4.6
通讯作者：
Baumberg JJ
中科院分区：
文献类型：
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作者：
Zhang L;Herrmann LO;Baumberg JJ
由于等离子体纳米结构能够将光限制在半导体内部的极小体积内，因此在提高太阳能水分解效率方面显示出巨大的前景。虽然尺寸对Au纳米颗粒(AuNPs)的等离子体性能起着关键作用，但其对等离子体辅助水分离的影响仍不完全清楚。这一点对于低带隙半导体尤其适用，因为它们的带间激发发生在与等离子体共振重叠的波长区域。在这里，用直径从10到80 nm的AuNPs修饰BiVO_4薄膜以研究等离子体激元效应的尺寸依赖关系。等离子体共振能量转移(PRET)被发现是提高BiVO4裂水效率的主要作用。BiVO4/AuNP的“热电子”注入效应较弱。这归因于BiVO4的带间激发，不利于热电子在BiVO4导带内的积累。对于较大直径的AuNPs，共振散射效应也有助于提高水的分解效率。这也是首次发现，在较大的非正常照射角时，可以获得更高的Pret效应。
Plasmonic nanostructures show great promise in enhancing the solar water splitting efficiency due to their ability to confine light to extremely small volumes inside semiconductors. While size plays a critical role in the plasmonic performance of Au nanoparticles (AuNPs), its influence on plasmon-assisted water splitting is still not fully understood. This holds especially true for low band gap semiconductors, for which interband excitations occur in wavelength regions that overlap with plasmonic resonances. Here, BiVO4 films are modified with AuNPs of diameters varying from 10 to 80 nm to study the size dependence of the plasmonic effect. Plasmon resonance energy transfer (PRET) is found to be the dominant effect in enhancing the water splitting efficiency of BiVO4. “Hot electron” injection effect is weak in the case of BiVO4/AuNP. This is attributed to the interband excitation of BiVO4, which is unfavourable for the hot electrons accumulation in BiVO4 conduction band. The resonant scattering effect also contributes to the enhanced water splitting efficiency for the larger diameter AuNPs. It is also for the first time found that higher PRET effect can be achieved at larger off-normal irradiation angle.