Au-Ag合金纳米球壳光吸收和后向散射特性的优化

Optimization of Light Absorption and Backscattering Characteristics of Au-Ag Alloy Nanoshells

为了找到光吸收和后向散射特性更好的纳米球壳,利用双层同心球的Mie散射理论和介电函数的尺寸修正模型定量分析了Au-Ag合金纳米球壳的内核半径、外壳厚度、合金成分和周围介质对光吸收和后向散射特性的影响。结果表明,当Au的摩尔分数为50%,步距为0.01 nm,内核分别为SiO_(2)和真空情况时,Au-Ag合金纳米球壳的体积吸收系数最大值分别为93.660μm^(-1)和99.316μm^(-1)时,内核半径分别为27.89 nm和28.02 nm,外壳厚度分别为3.95 nm和3.35 nm;后向散射系数的最大值分别为5.280μm^(-1)和5.550μm^(-1)时,内核半径分别为56.08 nm和56.37 nm,外壳厚度分别为10.47 nm和8.89 nm。此外,当Au的摩尔分数小于9%时,Au-Ag合金纳米球壳的光吸收特性优于Au纳米球壳;当Au的摩尔分数小于11%时,Au-Ag合金纳米球壳的后向散射特性优于Au纳米球壳。

To find alloy nanoshells with better light absorption and backscattering properties,we quantitatively analyze the effects of the core radius,shell thickness,alloy composition,and ambient medium of Au-Ag alloy nanoshells on the light absorption and backscattering properties.In the process,the Mie scattering theory of double-layer concentric spheres and the size correction model of dielectric functions are adopted.The results show that when the Au molar fraction of 50%,the size step of 0.01 nm,the inner core is SiO_(2) and vacuum,the maximum volume absorption coefficients of Au-Ag alloy nanoshells are respectively 93.660μm^(-1) and 99.316μm^(-1),with the inner core radius of 27.89 nm and 28.02 nm and the shell thicknesses of 3.95 nm and 3.35 nm.When the maximum volume backscattering coefficients are respectively 5.280μm^(-1) and 5.550μm^(-1),with the inner core radius of 56.08 nm and 56.37 nm and the shell thicknesses of 10.47 nm and 8.89 nm.When the Au molar fraction is less than 9%,the light absorption characteristics of Au-Ag alloy nanoshells are better than those of Au nanoshells.When the Au molar fraction is lower than 11%,the Au-Ag alloy nanoshells are superior to Au nanoshells in backscattering characteristics.