基于离散偶极近似理论,模拟分析了四种不同钴纳米结构的光学性质,具体讨论了钴单质半径、钴金合金材料的组分、钴金核壳结构中的内核大小及壳厚度、钴空心球的尺寸及空球壳厚度等参数对其消光光谱的影响。结果表明,半径50 nm的钴颗粒水溶液消光效率最大,且散射强度优于吸收；中空钴球相比实心颗粒消光谱红移,内半径40 nm、壳厚5 nm的空心钴纳米结构在可见光区域的消光效率最高；半径50 nm、钴金原子成分比值为1的合金颗粒在可见光区域具有较宽的散射光谱；随钴金核壳结构中核壳尺寸的增大,消光谱都由显示有两个峰位的波形演化为一个半高宽较大的波形,颗粒特性受核壳金属的共同作用。这些结果可以为其在太阳能领域等应用中的结构参数选择提供参考和借鉴。

Based on the discrete dipole approximation theory,the optical properties of four kinds of cobalt nanostructures were simulated.The parameters that are the radius of cobalt nanoparticle,the atom ratio of cobalt-gold alloy,the thickness of core and shell of cobalt@gold core-shell structure,the size of hollow cobalt particles affect the extinction spectra of these structures,which were discussed.The results show that the cobalt nanoparticle with 50 nm radius has the maximal extinction efficiency; moreover the scattering efficiency excels its absorption.The extinction efficiency of hollow cobalt nanoparticle red shifts compared to that of the solid particle,and it has the maximal efficiency spectrum located at the visible region when the inner radius equals to 40 nm and the shell thickness is 5 nm.The cobalt-gold alloy with atom ratio 1 has a broad scattering spectrum in the range of visible region.The extinction spectra of cobalt@gold core-shell structure nanoparticles change from two peaks to one peak with a wider half-peak width when the thickness of the core or shell is increased.The property of cobalt@gold core-shell structure depends on the interaction of core and shell metal.These results can provide some suggestion for choosing the structural parameters in practical application,such as solar energy field.