Diatoms are single-celled algaes that make photonic-crystal-like silica shells or frustules with hierarchical micro- and
nano-scale features consisting of two-dimensional periodic pores. In this paper, we present an innovative label-free
optical sensor based on a biological-plasmonic hybrid nanostructure by self-assembling silver (Ag) nanoparticles into
diatom frustules. The photonic-crystal-like diatom frustules provide a spatially confined electric field with enhanced
intensity that can form hybrid photonic-plasmonic modes through the optical coupling with Ag nanoparticles. The
experimental results demonstrate 4-6x and 9-12x improvement of sensitivities to detect the Raman dye for resonance
and nonresonance SERS sensing, respectively.
Dye-sensitized solar cells (DSSCs) rely on a network of titanium dioxide nanoparticles for electron transport and must balance carrier generation and collection. Adding photonic structures may increase light capture without affecting carrier collection. Diatoms are single-celled algae that biologically fabricate silicon dioxide cell walls which resemble photonic crystal slabs. We present a simple fabrication strategy that allows for uniform and controlled placement of biosilica within DSSCs. Integration of biosilica reduces photoanode transmittance to less than 5% prior to dye sensitization at loading levels as low as 6 wt% biosilica. Increased biosilica loading (17 wt%) provides additional enhancements in photocurrent generation. Reflectance measurements suggest that the enhancement results from the combined effects of photonic resonance and Mie scattering. Overall efficiency of these devices is improved by 8% and 14%, respectively.
Diatoms are a group of single-celled photosynthetic algae that make skeletal shells of hydrated amorphous silica, called
frustules, which possess hierarchical nanoscale photonic crystal features made by a bottom-up approach at ambient
temperature and pressure. In this paper, we theoretically investigate electric field enhancements of plasmonic
nanoparticles coated on the surface of diatom skeletal shells. Surface-Enhanced Raman Scattering substrates are
prepared by evaporating 10 nm thick silver film and self-assembling silver nanoparticles on diatom surfaces, which show
significantly better SERS signals than silver nanoparticles on flat glass substrates.