Fabrication of Jingle‐Bell‐Shaped Core–Shell Nanoparticulate Films and Molecular‐Size‐Responsive Photoluminescence Quenching of Cadmium Sulfide Cores

Size-selective photoetching of multilayered films of SiO2-coated CdS nanoparticles induces a blue shift in their diffuse reflectance spectra, indicating the formation of jingle-bell-shaped CdS/SiO2 core–shell nanoparticles in the film (see figure). Photoluminescence quenching of the as-photoetched films is attributed to the molecular-size-selective penetration of the quencher from the bulk solution to the void space through the pores of the SiO2 shell.