实现纳米流体全光谱近完美光热转换

Achieving Near-Perfect Full-Spectrum Photothermal Conversion Based Nanofluids

本文研究了不同材料以及不同半径组合的核壳结构纳米流体的光热转换效果。同时考虑材料实际的色散特征,基于遗传算法,在所研究的十种材料中,优化选择得到了最佳的核壳材料以及半径的组合参数,在全光谱(0.2~2.5μm)范围内实现了近完美的光热转换效果。计算结果表明,将常见的SiO2材料作为核,金属Ni或者TiN作为壳,合理地选择核壳的半径参数,均能实现99%以上的光热转换效果。特别地,在相同的几何参数下,对于SiO2@Ni以及SiO2@TiN纳米流体,因其能在宽光谱范围内有效地激发等离子体共振,其光热转换效率(99.83%)是传统的由纯Ag、Au纳米流体的约2倍,是SiO2@Ag或SiO2@Au纳米流体的1.2倍左右。本文的研究方法不仅对于设计性能更加优秀的纳米流体组合材料具有指导意义,在实际应用中,可对纳米粒子的几何尺寸进行优化,进一步降低生成成本的同时实现全光谱高效的光热转换.

In this paper,the performance of photothermal conversion for nanofluids with different sizes and materials have been studied.Based on genetic algorithms,we obtain the optimized materials and sizes for core@shell nanoparticles with consideration of optical dispersion,thereby near-perfect full-spectrum solar-to-thermal conversion has been ideally achieved.Results show that,as for SiO2@Ni(or TiN) nanoparticles,the photothermal conversion efficiency can reach over 99%,attributed to broadband absorption performance covering the nearly whole solar spectrum.Specifically,under the condition with the same radius of core and shell for different materials,the efficiency of SiO2@TiN nanofluids is more than two times than that of Au nanofluids,more than 1.2 times than those of SiO2@Ag and SiO2@Au nanofluids.The methods applied in this paper and results will give some guidance for designing nanofluids with optimized performances,which is helpful to reduce the cost of materials and make the best of solar energy.