Thickness Effects on Light Absorption and Scattering for Nanoparticles in the Shape of Hollow Spheres

• Published in: Journal of physical chemistry. C Vol. 119; no. 46; pp. 25754 - 25760
• Main Authors: Lee, Jeng-Yi, Tsai, Min-Chiao, Chen, Po-Chin, Chen, Ting-Ting, Chan, Kuei-Lin, Lee, Chi-Young, Lee, Ray-Kuang
• Format: Journal Article
• Language: English
• Published: American Chemical Society 19.11.2015
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/acs.jpcc.5b08435

We reveal the thickness effects on optical properties for nanoparticles in the shape of hollow spheres theoretically and experimentally. Within and beyond the electrically small limit, hollow spheres are shown to have almost the same light absorption power as that of solid ones, when the ratio of inner core to whole particle radii is smaller than 0.4. It means that one can maintain the level of light absorption even with a large empty core. In the electrically small limit, we expand the exact solution of Mie theory in power of the thickness parameter and show that the thickness ratio has less influence on light absorption. Moreover, we synthesize highly uniform hollow spheres of TiO2 anatase through a self-sacrificing template method. A variety of particle radii from 94 to 500 nm, with 50 nm in the shell thickness, are performed experimentally in photocatalytic activity. With experimental demonstrations and theoretical simulations, our results provide a guideline in the design on the thickness for hollow-sphere nanoparticles with an optimized absorption power in light harvesting.