Xu Yunkun, Fan Yulong, Qing Ye Ming, Cui Tie Jun, Lei Dangyuan
Department of Materials Science and Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong, China.
State Key Laboratory of Millimetre Waves, School of Information Science and Engineering, Southeast University, Nanjing 210096, China.
Nanophotonics. 2022 Feb 10;11(11):2453-2464. doi: 10.1515/nanoph-2021-0610. eCollection 2022 Jun.
Since its first observation in 2014, plasmoelectric potential (PEP) has drawn a great deal of research interest in all-metal optoelectronics and photochemistry. As an optical thermodynamic phenomenon induced by the electron number dependent equilibrium temperature in plasmonic nanostructures, the early theoretical model developed for calculating PEP is only applicable to Mie-resonant nanostructures, such as a gold nanosphere on a conductive indium tin oxide (ITO) substrate, where the transfer efficiency of hot electrons from gold to ITO can be analytically determined. Without the presence of the substrate, the temperature increase on the gold nanosphere induced by plasmonic absorption was calculated on the basis of thermal radiation in vacuum, which probably over-estimates the actual temperature increase in comparison to realistic experimental conditions. Here, we propose an equilibrium-thermodynamics computational method to quantify the actual efficiency of plasmon-induced electron transfer between a non-Mie-resonant metallic nanostructure and a conductive substrate and hence determine the resultant plasmoelectric potential. With a less than 2.5% relative error in predicting the steady-state temperature of a Mie-resonant nanoparticle in vacuum, and a more strict evaluation of the plasmonic local heating induced temperature increase in a single plasmonic nanostructure or an array of such structures under continuous-wave illumination (CWI), our generalized method provides a robust and accurate approach for quantifying PEP in various plasmonic-particle (array)-on-film nanocavities.
自2014年首次被观测到以来，等离子体电势（PEP）在全金属光电子学和光化学领域引发了大量研究兴趣。作为一种由等离子体纳米结构中依赖电子数的平衡温度所诱发的光学热力学现象，早期用于计算PEP的理论模型仅适用于米氏共振纳米结构，比如导电氧化铟锡（ITO）衬底上的金纳米球，在这种结构中，热电子从金向ITO的转移效率可以通过解析方法确定。在没有衬底的情况下，基于真空中的热辐射计算了等离子体吸收在金纳米球上引起的温度升高，与实际实验条件相比，这可能高估了实际的温度升高。在此，我们提出一种平衡热力学计算方法，以量化非米氏共振金属纳米结构与导电衬底之间等离子体诱导电子转移的实际效率，进而确定由此产生的等离子体电势。我们的通用方法在预测真空中米氏共振纳米粒子的稳态温度时，相对误差小于2.5%，并且在连续波照明（CWI）下，对单个等离子体纳米结构或此类结构阵列中等离子体局部加热引起的温度升高进行了更严格的评估，为量化各种薄膜上等离子体粒子（阵列）纳米腔中的PEP提供了一种稳健且准确的方法。
