Plasmonic Au/TiO2‐Dumbbell‐On‐Film Nanocavities for High‐Efficiency Hot‐Carrier Generation and Extraction,Advanced Functional Materials

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Plasmonic Au/TiO2‐Dumbbell‐On‐Film Nanocavities for High‐Efficiency Hot‐Carrier Generation and Extraction
Advanced Functional Materials ( IF 18.5 ) Pub Date : 2018-07-10 , DOI: 10.1002/adfm.201800383
Kwun Hei Willis Ho ₁ , Aixue Shang ₁ , Fenghua Shi ₁ , Tsz Wing Lo ₁ , Pui Hong Yeung ₁ , Yat Sing Yu ₁ , Xuming Zhang ₁ , Kwok-yin Wong ₂ , Dang Yuan Lei ₁

Affiliation

Plasmon‐induced hot carriers have vast potential for light‐triggered high‐efficiency carrier generation and extraction, which can overcome the optical band gap limit of conventional semiconductor‐based optoelectronic devices. Here, it is demonstrated that Au/TiO₂ dumbbell nanostructures assembled on a thin Au film serve as an efficient optical absorber and a hot‐carrier generator in the visible region. Upon excitation of localized surface plasmons in such coupled particle‐on‐film nanocavities, the energetic conduction electrons in Au can be injected over the Au/TiO₂ Schottky barrier and migrated to TiO₂, participating in the chemical reaction occurring at the TiO₂ surface. Compared with the same dumbbell nanostructures on an indium tin oxide (ITO) film, such nanocavities exhibit remarkable enhancement in both photocurrent amplitude and reaction rate that arise from increased light absorption and near‐field amplification in the presence of the Au film. The incident‐wavelength‐dependent photocurrent and reaction rate measurements jointly reveal that Au‐film‐mediated near‐field localization facilitates more efficient electron–hole separation and transport in the dumbbells and also promotes strong d‐band optical transitions in the Au film for generation of extra hot electrons. Such nanocavities provide a new plasmonic platform for effective photoexcitation and extraction of hot carriers and also better understanding of their fundamental science and technological implications in solar energy harvesting.

中文翻译：

等离子Au / TiO2薄膜哑铃纳米腔，用于高效热载流子的产生和提取

等离子体激发的热载流子具有光触发的高效载流子产生和提取的巨大潜力，可以克服传统的基于半导体的光电器件的光带隙限制。在此证明，组装在Au薄膜上的Au / TiO ₂哑铃纳米结构在可见光区域可作为有效的光吸收剂和热载流子。在这种耦合的膜上纳米粒子腔中激发局部表面等离子体激元后，Au中的高能传导电子可以注入到Au / TiO ₂肖特基势垒上方并迁移到TiO ₂，参与在TiO ₂处发生的化学反应表面。与铟锡氧化物（ITO）膜上的相同哑铃纳米结构相比，此类纳米腔在光电流振幅和反应速率方面均表现出显着增强，这是由于存在Au膜时增加了光吸收和近场放大而引起的。与入射波长有关的光电流和反应速率的测量结果共同表明，金膜介导的近场定位促进了哑铃中电子空穴的更有效分离和传输，并促进了金膜中强的d波段光学跃迁的产生。多余的热电子。此类纳米腔为有效的光激发和热载流子提取提供了新的等离激元平台，并更好地了解了它们在太阳能收集中的基本科学技术意义。

更新日期：2018-07-10

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