Au@碳球复合结构中Au颗粒位置调控光吸收

采用时域有限差分（FDTD）法研究Au纳米颗粒@碳球（AuNPs@CS）复合结构的光吸收控制。发现Au纳米颗粒@碳球复合结构中Au颗粒的位置可以控制复合结构光吸收。模型计算中选取两粒Au纳米颗粒以最佳深度（0 nm）嵌入碳球表面。当两粒Au颗粒球心与碳球球心夹角为22.5°和45°时，复合结构光吸收较单一碳球光吸收明显增强；当夹角为315°、270°、180°、90°时，光吸收增量逐渐减小；当夹角为337.5°时，光吸收量低于单一碳球。这一结果主要归因于Au纳米颗粒位置变化可引起表面等离子体光强度和光散射方向的变化。改变碳球表面Au纳米颗粒的数量和位置，可以进一步调节AuNPs@CS复合结构的光吸收。

Regulation of Light Absorption with Position of Au Particles in a Au@Carbon Sphere Composite Structure

Light absorption of Au nanoparticles@carbon sphere (AuNPs@CS) composite structure is investigated with finite difference time domain (FDTD) method. It shows that light absorption of AuNPs@CS composite structure is effectively controlled by position of Au nanoparticle.Two Au nanoparticles are selected and embedded on the surface of the carbon sphere at an optimal depth (0 nm). As the angle between the particle center of Au and the spheroid core of carbon sphere is 22.5° and 45°, light absorption is enhanced than that of a single carbon sphere; As the angles between them are 315°, 270°, 180° and 90°, the increment of light absorption decreases gradually; At an angle of 337.5° between them, the optical absorption is significantly lower than that of a single carbon sphere. It may be attributed to the change of Au nanoparticles position, which causes the change of light intensity and scattering direction of the surface plasmon. The light absorption of AuNPs@CS composite structure can be adjusted by varying the number and position of Au nanoparticle on the surface of carbon sphere.