title: Enhanced photoabsorption efficiency of incomplete nanoshells.
abstract: The rather low scattering or extinction efficiency of small nanoparticles, metallic and otherwise, is significantly enhanced when they are adsorbed on a larger core particle. But the photoabsorption by particles with varying surface area fractions on a larger core particle is found to be limited by saturation. It is found that the core-shell particle can have a lower absorption efficiency than a dielectric core with its surface partially nucleated with absorbing particles-an "incomplete nanoshell" particle. We have both numerically and experimentally studied the optical efficiencies of titania (TiO2) nucleated in various degrees on silica (SiO2) nanospheres. We show that optimal surface nucleation over cores of appropriate sizes and optical properties will have a direct impact on the applications exploiting the absorption and scattering properties of such composite particles.
authors.affiliation: Computational Photonics Laboratory, SERC, Indian Institute of Science, Bangalore 560012, India. murugesh@serc.iisc.ernet.in
authors.forename: Murugesan
authors.initials: M
authors.lastname: Venkatapathi
authors.forename: Sudipta G
authors.initials: SG
authors.lastname: Dastidar
authors.forename: P
authors.initials: P
authors.lastname: Bharath
authors.forename: Arindam
authors.initials: A
authors.lastname: Roy
authors.forename: Anupam
authors.initials: A
authors.lastname: Ghosh
mesh_terms: D000042:Absorption; D053758:Nanoparticles / Q000737:chemistry*; D055620:Optical Phenomena; D012822:Silicon Dioxide / Q000737:chemistry
chemical_list: D012822:Silicon Dioxide