Tandon Bharat, Gibbs Stephen L, Dean Christopher, Milliron Delia J
McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712, United States.
Nano Lett. 2023 Feb 8;23(3):908-915. doi: 10.1021/acs.nanolett.2c04199. Epub 2023 Jan 19.
Electron transfer to and from metal oxide nanocrystals (NCs) modulates their infrared localized surface plasmon resonance (LSPR), revealing fundamental aspects of their photophysics and enabling dynamic optical applications. We synthesized and chemically reduced dopant-segregated Sn-doped InO NCs, investigating the influence of radial dopant segregation on LSPR modulation and near-field enhancement (NFE). We found that core-doped NCs show large LSPR shifts and NFE change during chemical titration, enabling broadband modulation in LSPR energy of over 1000 cm and of peak extinction over 300%. Simulations reveal that the evolution of the LSPR spectra during chemical reduction results from raising the surface Fermi level and increasing the donor defect density in the shell region. These results establish dopant segregation as a useful strategy to engineer the dynamic optical modulation in plasmonic semiconductor NC heterostructures going beyond what is possible with conventional plasmonic metals.
金属氧化物纳米晶体（NCs）的电子转移调控其红外局域表面等离子体共振（LSPR），揭示了其光物理的基本方面，并实现了动态光学应用。我们合成并化学还原了掺杂剂分离的Sn掺杂InO NCs，研究了径向掺杂剂分离对LSPR调制和近场增强（NFE）的影响。我们发现，核掺杂的NCs在化学滴定过程中表现出较大的LSPR位移和NFE变化，能够实现超过1000 cm的LSPR能量宽带调制以及超过300%的峰值消光。模拟结果表明，化学还原过程中LSPR光谱的演变是由于表面费米能级升高和壳层区域施主缺陷密度增加所致。这些结果表明，掺杂剂分离是一种有用的策略，可用于设计等离子体半导体NC异质结构中的动态光学调制，这超越了传统等离子体金属所能实现的范围。
