Novel plasmonic–photonic Janus films with aluminum nanoisland-coated colloidal arrays for versatile applications†

Plasmonic nanostructures provide unique structural coloration features via resonant interactions with light, rendering them useful in various optical applications. Here, new types of novel plasmonic–photonic Janus (PPJ) films are developed by introducing aluminum nanoislands on the surface of colloidal photonic crystal (CPC) arrays. Notably, the obtained PPJ films show vivid and tunable plasmonic colors ranging from purple to golden that can be regulated by the sizes of nanoisland architectures. Exquisite multicolored patterns on PPJ films have also been successfully achieved via regioselective deposition, showcasing enormous potential in decorations. More intriguingly, by virtue of the sensitivity of Al nanoislands to the medium, the PPJ films display superior colorimetric detection ability in response to different solvents and biomolecule glucose. Leveraging these merits, advanced rewritable papers and reliable express waybills have been demonstrated based on PPJ films, offering abilities to deliver information reversibly and erase them on-demand. This work establishes a new platform for achieving versatile applications within a single plasmonic system, opening up vast possibilities for advancements in information delivery and personal information security.