Charge carrier concentration dependence of ultrafast plasmonic relaxation in conducting metal oxide nanocrystals
Charge carrier concentration dependence of ultrafast plasmonic relaxation in conducting metal oxide nanocrystals
复制标题
DOI：
10.1039/c7tc00600d
复制
发表时间：
2017-06
影响因子：
6.4
通讯作者：
Robert W. Johns;Michelle A. Blemker;Michael S. Azzaro;S. Heo;Evan L. Runnerstrom;D. Milliron;S. Roberts
中科院分区：
文献类型：
--
作者：
Robert W. Johns;Michelle A. Blemker;Michael S. Azzaro;S. Heo;Evan L. Runnerstrom;D. Milliron;S. Roberts
电子掺杂的金属氧化物纳米晶体表现出可调谐的红外局域表面等离子体共振（LSPR）。尽管IR共振LSPR在溶液可加工纳米晶体中具有许多益处，但主体半导体材料的电子结构影响金属氧化物LSPR的方式仍在研究中。半导体提供了一种替代的介电环境，而不是金属键合的固体，如贵金属，这可能会影响这些材料在光激发后如何经历电子弛豫。了解这些差异是开发利用等离子体金属氧化物NC提供的独特光学和电子特性的应用的关键。在这里，我们使用双温度模型结合飞秒瞬态吸收实验来描述两个代表性的金属氧化物双金属氧化物系统，立方WO3−x和方铁锰矿Sn掺杂的In2O3的内部温度如何在LSPR激发后变化。我们发现，与金属纳米晶体如Ag相比，金属氧化物NC的低自由载流子浓度导致较低效率的热生成。这表明金属氧化物NC可能非常适合那些不良发热可能会破坏应用整体性能的应用，例如太阳能转换和光子门控。
Electronically doped metal oxide nanocrystals exhibit tunable infrared localized surface plasmon resonances (LSPRs). Despite the many benefits of IR resonant LSPRs in solution processable nanocrystals, the ways in which the electronic structure of the host semiconductor material impact metal oxide LSPRs are still being investigated. Semiconductors provide an alternative dielectric environment than metallically bonded solids, such as noble metals, which can impact how these materials undergo electronic relaxation following photoexcitation. Understanding these differences is key to developing applications that take advantage of the unique optical and electronic properties offered by plasmonic metal oxide NCs. Here, we use the two-temperature model in conjunction with femtosecond transient absorption experiments to describe how the internal temperature of two representative metal oxide nanocrystal systems, cubic WO3−x and bixbyite Sn-doped In2O3, change following LSPR excitation. We find that the low free carrier concentrations of metal oxide NCs lead to less efficient heat generation as compared to metallic nanocrystals such as Ag. This suggests that metal oxide NCs may be ideal for applications wherein untoward heat generation may disrupt the application's overall performance, such as solar energy conversion and photonic gating.