This paper describes the one-pot, aqueous synthesis of cationic polymer nanofibers with embedded silver nanoparticles. Poly[2-(tert-butylaminoethyl) methacrylate] (PTBAM) was used as a cationic polymer substrate to reinforce the antimicrobial activity of the embedded silver nanoparticles. Electron microscope analyses revealed that the as-synthesized nanofibers had diameters of approximately 40 nm and lengths up to about 10 μm. Additionally, silver nanoparticles of approximately 8 nm in diameter were finely embedded into the prepared nanofibers. The embedded silver nanoparticles had a lower tendency to agglomerate than colloidal silver nanoparticles of comparable size. In addition, the nanofibers with embedded silver nanoparticles exhibited excellent antibacterial performance against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus. Interestingly, the prepared nanofibers exhibited enhanced bactericidal performance compared with the silver-embedded poly(methyl methacrylate) (PMMA) nanofibers, presumably because of the antibacterial properties of the PTBAM substrate.

SiO2/TiO2 core/shell nanoparticles (STCS-NPs) with diameters of 110, 240, and 530 nm were fabricated to investigate the influence of the size and refractive index of light-scattering particles on light-scattering properties. The optical properties of STCS-NPs were evaluated and compared with SiO2-NPs and TiO2-NPs. The structure of STCS-NPs, consisting of a low refractive index core and high refractive index shell, provides efficient light scattering. The optimized anode film with STCS-NPs had ca. 20% improved power conversion efficiency (PCE).

1wileyonlinelibrary.com nanomaterial's size, surface area, and light-scattering ability.Recently, multi-shell hollow nanoparticles (MS-HNPs) have been highlighted as promising materials for DSSC applications, offering a high surface area and strong light scattering. MS-HNPs, composed of inner and outer shells, have a benefi cial confi guration for multirefl ection (of sunlight) and redox reactions with the electrolyte. Moreover, the surface area of MS-HNPs is much larger than that of single-shell (SS)-HNPs having the same size. Various MS-HNPs have been developed, such as multilayerd SnO 2 hollow microspheres coated to TiO 2 , [ 17 ] quintuple-shelled SnO 2 hollow microspheres, [ 18 ] multi-shelled ZnO hollow microspheres, [ 19 ] and shell-in-shell TiO 2 hollow microspheres. [ 20 ] These MS-HNPs improve the power conversion effi ciency of the DSSCs, due to their strong lightscattering effect and increased surface area. However, among the MS-HNPs, the largest surface area of multi-shelled ZnO hollow microspheres was only 47 m 2 g −1 , which is not suffi cient for light absorption in the sensitizer layer. [ 19 ] Additionally, most MS-HNPs are synthesized using a hydrothermal process, which limits the mass production of MS-HNPs. In particular, TiO 2 , commonly used as the working electrode in DSSCs, has several fabrication issues, including diffi culty in controlling the morphology, size, and aggregation, due to the fast reaction rate of the TiO 2 precursor. [ 21,22 ] Therefore, the development of MS-HNPs with nano-scale size, high surface area, and strong light-scattering remains a challenge.Herein, we introduce a fabrication method for nano-sized MS-TiO 2 -HNPs using a sol-gel method, combined with calcination and etching processes. The MS-TiO 2 -HNPs used in this study were composed of three shells: a small inner shell (diameter: 50 nm), a middle shell (diameter: 100 nm), and an outer shell (diameter: 160 nm). The fabricated MS-TiO 2 -HNPs were expected to be multifunctional, due to their large surface area of 171 m 2 g −1 , multi-refl ection capability, and enhanced electrolyte diffusion. Specifi cally, the smallest inner shell of the MS-TiO 2 -HNPs provided a high surface area. Additionally, the multi-shell structure induced multirefl ection for solar devices. We observed an increase in the power conversion effi ciency for the MS-TiO 2 -HNP-DSSCs of 17.5% (from 8.0% for SS-TiO 2 -HNP-DSSCs to 9.4% for MS-TiO 2 -HNP-DSSCs). To our knowledge, this is the fi rst report of nano-sized MS-TiO 2 -HNPs with a high surface area. Multi-Shell Porous TiO 2 Hollow Nanoparticles for Enhanced Light Harvesting in

Novel ZnO/TiO(2) composite nanofibers were fabricated by an electrospinning method and showed excellent antimicrobial activity against gram-negative Escherichia coli and gram-positive Staphylococcus aureus under UV irradiation and in the absence of light.