局域表面等离子体共振效应气体传感器的研究进展

贵金属纳米结构的局域表面等离子体共振光学在光催化、光学传感器、表面增强光谱学、太阳能电池等领域具有广阔的应用前景。基于贵金属的局域表面等离子体共振效应传感器的性能主要依赖于贵金属的结构,总结了纳米贵金属粒子性质以及各种结构的制备方法和应用,并展望了未来表面等离子体共振效应传感器的发展趋势。     

基于局域表面等离子体共振效应生物传感器的制备方法及应用

金属纳米颗粒表现出来的局域表面等离子体共振效应被广泛应用于生物传感器领域.综述了局域表面等离子体共振效应的基本原理,对比了局域表面等离子体和表面等离子体的异同,详细介绍了胶体化学平板印刷术、电子束光刻法、聚焦离子束光刻法、纳米球光刻术等多种金属纳米颗粒阵列和图形制备技术、特点及应用,分析了局域表面等离子体共振生物传感器的应用前景、现存问题及其解决途径.     

Localized Defects on Copper Sulfide Surface for Enhanced Plasmon Resonance and Water Splitting

Surficial defects in semiconductor can induce high density of carriers and cause localized surface plasmon resonance which is prone to light harvesting and energy conversion, while internal defects may cause serious recombination of electrons and holes. Thus, it is significant to precisely control the distribution of defects, although there are few successful examples. Herein, an effective strategy to confine abundant defects within the surface layer of Cu_1.94S nanoflake arrays (NFAs) is reported, leaving a perfect internal structure. The Cu_1.94S NFAs are then applied in photoelectrochemical (PEC) water splitting. As expected, the surficial defects give rise to strong LSPR effect and quick charge separation near the surface; meanwhile, they provide active sites for catalyzing hydrogen evolution. As a result, the NFAs achieve the top PEC properties ever reported for Cu_xS‐based photocathodes.     

An Inverted Surface Plasmon Resonance

Abstract

An inverted surface plasmon resonance is observed by measuring the internal reflectivity of a bilayer chromium-gold thin film deposited on a high index glass prism. With incident transverse magnetic radiation and suitable choice of chromium and gold thicknesses a strong resonance maximum is recorded which is nearly as narrow as the more commonly observed surface plasmon resonance minimum for gold. A peak reflectivity of order 40% has been recorded which with fine adjustment of the film thickness may be increased to perhaps 80% although it never approaches 100% because of the intrinsic absorption by the chromium. The angle dependent reflectivity data obtained are analysed using a multilayer Fresnel equation model and optical field and power loss profiles through the resonance are presented to illustrate its nature.     

Localized Surface Plasmon Induced Position‐Sensitive Photodetection in Silicon‐Nanowire‐Modified Ag/Si

Surface plasmon‐based approaches are widely applied to improve the efficiency of photoelectric devices such as photosensors and photocells. In order to promote the light absorption and electron–hole pair generation in devices, metallodielectric nanostructures are used to boost the growth of surface plasmons. Here, silicon nanowires (SiNWs) are used to modify a metal–semiconductor structure; thus, Ag/SiNWs/Si is manufactured. In this system, a large increased lateral photovoltaic effect (LPE) is detected with a maximum positional sensitivity of 65.35 mV mm^?1, which is ≈53‐fold and 1000‐fold compared to the conventional Ag/Si (1.24 mV mm^?1) and SiNWs/Si (0.06 mV mm^?1), respectively. It is demonstrated that localized surface plasmons (LSPs) contribute a lot to the increment of LPE. Furthermore, through the surface‐enhanced Raman scattering spectra of rhodamine‐6G and finite‐difference time‐domain simulation, it is illustrated that silver‐coated SiNWs support strong LSPs. The results propose an enhancement mechanism based on LSPs to facilitate the photoelectric conversion in LPE and offer an effective way to improve the sensitivity of photodetectors.     

银纳米球阵列的局域表面等离子体特性研究

基于金属纳米颗粒的光散射理论,利用时域有限差分法计算了Ag纳米球阵列不同结构参数下的散射光谱、吸收光谱及散射效率,分析了Ag纳米球阵列在共振波长下的极化电场和极化电荷分布情况,讨论了Ag纳米球阵列的局域表面等离子体(LSP)对GaN基LED发光效率增加的机理。结果表明,随着间距的减小,Ag纳米球阵列LSP的散射峰逐渐呈双模分布,且位于长波段的散射峰蓝移;随着Ag纳米球直径的增大,LSP的共振波长红移且散射效率增大。当LSP的共振波长与LED辐射光波长相匹配时,Ag纳米球阵列的LSP与LED辐射光发生耦合作用,在一定条件下,部分耦合的能量辐射到自由空间,增大LED的内量子效率。     

差分表面等离激元共振传感仿真研究

从薄膜光学理论出发,对不同金属膜厚度、不同实折射率和不同复介电常数的环境介质的表面等离激元共振(SPR,Surface Plasmon Resonance)信号进行了分析,给出了最佳金属膜厚度,并且,折射率与共振角呈线性关系(R=0.999 4).分析了采用差分处理时,随环境介质的复介电常数变化的光反射率曲线.结果表明,同组两个探测器信号的和随环境介电常数的虚部变化,与实部无关,其信号差则相反,因此,能够同时测量环境介质的介电常数的实部和虚部.     

Localized Surface Plasmon Resonance Enhanced Light Absorption in AuCu/CsPbCl3 Core/Shell Nanocrystals

Localized surface plasmon resonance (LSPR) is shown to be effective in trapping light for enhanced light absorption and hence performance in photonic and optoelectronic devices. Implementation of LSPR in all-inorganic perovskite nanocrystals (PNCs) is particularly important considering their unique advantages in optoelectronics. Motivated by this, the first success in colloidal synthesis of AuCu/CsPbCl₃ core/shell PNCs and observation of enhanced light absorption by the perovskite CsPbCl₃ shell of thickness in the range of 2–4 nm, enabled by the LSPR AuCu core of an average diameter of 7.1 nm, is reported. This enhanced light absorption leads to a remarkably enhanced photoresponse in PNCs/graphene nanohybrid photodetectors using the AuCu/CsPbCl₃ core/shell PNCs, by more than 30 times as compared to the counterparts with CsPbCl₃ PNCs only (8–12 nm in dimension). This result illustrates the feasibility in implementation of LSPR light trapping directly in core/shell PNCs for high-performance optoelectronics.     

Unprecedented Surface Plasmon Modes in Monoclinic MoO2 Nanostructures

Developing stable plasmonic materials featuring earth-abundant compositions with continuous band structures, similar to those of typical metals, has received special research interest. Owing to their metal-like behavior, monoclinic MoO₂ nanostructures have been found to support stable and intense surface plasmon (SP) resonances. However, no progress has been made on their energy and spatial distributions over individual nanostructures, nor the origin of their possibly existing specific SP modes. Here, various MoO₂ nanostructures are designed via polydopamine chemistry and managed to visualize multiple longitudinal and transversal SP modes supported by the monoclinic MoO₂, along with intrinsic interband transitions, using scanning transmission electron microscopy coupled with ultrahigh-resolution electron energy loss spectroscopy. The identified geometry-dependent SP energies are tuned by either controlling the shape and thickness of MoO₂ nanostructures through their well-designed chemical synthesis, or by altering their length using a developed electron-beam patterning technique. Theoretical calculations reveal that the strong plasmonic behavior of the monoclinic MoO₂ is associated with the abundant delocalized electrons in the Mo d orbitals. This work not only provides a significant improvement in imaging and tailoring SPs of nonconventional metallic nanostructures, but also highlights the potential of MoO₂ nanostructures for micro–nano optical and optoelectronic applications.     

Plasmon mediated Brillouin scattering of surface acoustic waves (in different directions to polymer line structures on a silver coated glass substrate)

In this paper measurement on the propagation of Rayleigh waves on the surface of polymer line structures on top of a silver layer were examined by using plasmon mediated Brillouin scattering. The line structures grating constants were 8, 4 and 1 μm. Spectra were recorded with different scattering angles and propagation directions with respect to the line direction. Three Rayleigh modes have been observed in samples with grating constants 8 and 4 μm. In the parallel direction, one mode is unshifted relative to a pure silver surface. In the perpendicular direction there is one unshifted and one shifted mode. The observed shift of 6 μm^− 1 is independent of the grating constant. The 1 μm sample shows a somewhat contrasting behavior. Two different scattering mechanisms, involving surface plasmons at each interface, are proposed to explain the observed effects.     

Inside Front Cover: One‐Dimensional Plasmon Coupling by Facile Self‐Assembly of Gold Nanoparticles into Branched Chain Networks (Adv. Mater. 21/2005)

Short, single‐particle‐wide chains and complex networks of interconnected chains are easily self‐assembled from 13 nm Au nanoparticles by inducing a surface electrostatic dipolar moment in a controlled manner. Mann and co‐workers further demonstrate both experimentally and theoretically on p. 2553 that efficient surface plasmon coupling takes place in these extensive networks, thus opening a new bottom–up approach to subwavelength optical‐waveguiding devices. The left panel in the image shows isolated 13 nm Au nanoparticles; the back panel, short linear chains; the bottom panel, complex branched network of chains; and the right panel, a graphical rendering of optical spectroscopic properties during the self‐assembly process.     

温度对表面等离子体振荡传感器的作用

本文采用棱镜型角度检测的方法,对表面等离子体振荡传感器进行精密检测.首先从理论上分析了温度对棱镜型表面等离子体传感器的作用机理,并根据机理进行了实验系统的设计.基于所设计的棱镜型角度检测SPR装置,研究了温度对表面等离子体振荡(SPR)共振角度的影响.实验给出了表面等离子体共振角度随被测液体温度的升高而下降的数值结果,斜率为-7.843×10-3/℃,并证明了温差控制对光传感技术中表面等离子体振荡(SPR)技术的实用化的重要性.