Geballe Laboratory for Advanced Materials, 476 Lomita Mall, Stanford, California 94305-4045, United States.
Nano Lett. 2011 Aug 10;11(8):3440-6. doi: 10.1021/nl201908s. Epub 2011 Jul 15.
Future generations of photoelectrodes for solar fuel generation must employ inexpensive, earth-abundant absorber materials in order to provide a large-scale source of clean energy. These materials tend to have poor electrical transport properties and exhibit carrier diffusion lengths which are significantly shorter than the absorption depth of light. As a result, many photoexcited carriers are generated too far from a reactive surface and recombine instead of participating in solar-to-fuel conversion. We demonstrate that plasmonic resonances in metallic nanostructures and multilayer interference effects can be engineered to strongly concentrate sunlight close to the electrode/liquid interface, precisely where the relevant reactions take place. On comparison of spectral features in the enhanced photocurrent spectra to full-field electromagnetic simulations, the contribution of surface plasmon excitations is verified. These results open the door to the optimization of a wide variety of photochemical processes by leveraging the rapid advances in the field of plasmonics.
为了提供大规模的清洁能源，未来用于太阳能燃料产生的光电管必须采用价格低廉、地球丰富的吸收材料。这些材料往往具有较差的电输运性能，并表现出载流子扩散长度明显短于光的吸收深度。因此，许多光激发的载流子在离反应表面太远的地方产生，并且重新结合而不是参与太阳能到燃料的转换。我们证明，金属纳米结构中的等离子体激元共振和多层干涉效应可以被设计用来将阳光强烈地集中在电极/液体界面附近，也就是相关反应发生的地方。通过将增强光电流谱中的光谱特征与全场电磁模拟进行比较，验证了表面等离子体激元激发的贡献。这些结果为通过利用等离子体学领域的快速发展来优化各种光化学过程开辟了道路。
