Photonic nanoarchitectonics with stimuli-responsive 2D materials

Abstract

The ability to produce structural color from inherently colorless materials, similar to that in butterfly wings and beetle shells, has attracted considerable research interest over the last three decades. Despite their extraordinary properties and performances, the field of structural colors based on inherently functional 2D materials only took off recently. In this minireview, we highlight the diversity of 2D materials utilized for achieving structural coloration in different architectures. We summarize the large tunability of photonic architectures based on 2D materials and emphasize their extraordinary dynamic response induced by external stimuli. Subsequently, recent strategies to tailor their properties with molecular and structural approaches are discussed. Finally, we point out promising future directions in this emerging field. Structural coloroverview and concepts 566 | Mol. Syst. Des. Eng., 2019, 4, 566-579 This journal is Design, System, ApplicationAs 2D materials are coming of age, their richness in composition, structure and properties offer a unique platform for the design of tailor-made nanoscale building blocks for functional devices. Combining the chemical scope, diverse optical properties and stimuli-responsive nature of 2D materials and their ensembles with the recent advancement in liquid-assisted assembly strategies, 2D materials have emerged as versatile building blocks in thin film-based photonic architectures, including Fabry-Pérot interference filters and 1D photonic crystals. To impart such architectures with maximum functionality, design strategies range from molecular level approaches such as ion exchange and intercalation, to morphology engineering such as porosity tuning. The integration of 2D materials into photonic architectures has opened up new horizons in the realization of smart devices, ranging from vapor and pressure sensors to functional surfaces allowing for the touchless tracking of finger motions. On a more fundamental level, thin films exhibiting tunable structural color allow for the observation of otherwise optically silent processes with the naked eye, such as intercalation into 2D materials. Cast into photonic architectures, the unique versatility of 2D materials and their molecularly engineered counterparts can be harvested to push the limits of label-free sensing, anticounterfeiting, radiation shielding, photovoltaics, display technology, and beyond.

Iridescence in nematics: Photonic liquid crystals of nanoplates in absence of long-range periodicity

“…Among various types of ordered nanoarchitectures, photonic liquid crystals (PLCs) of 2D nanomaterials have attracted recent attention owing to the ability of dynamically interacting with the light of interest to achieve brilliant reflection colors (11). Generally, the color of PLCs originates from the periodic structures with long-range positional ordering, such as lamellar or helical arrangement (12)(13)(14)(15)(16)(17).…”

Intercalation and flexibility chemistries of soft layered materials

“…5a and b). [72][73][74][75] The exfoliated nanosheets, such as phosphatoantimonic acid and tantalum phosphate, formed the thin films as the host layer several-hundred nanometer in thickness with re-stacking by spin coating (Fig. 5a).…”

Metalloporphyrins into Mesoporous Photonic Crystals: Towards Nanostructured Sensing Devices

“…Sensing by PC alone is usually achieved using the optical shift (Δλ/λ) arising from changes in the refractive index [35,36]. Therefore, the transmittance optical shifts for MP@PC towards different EDA concentrations were calculated, using the same principle with both the two maximums and the two minimums ( Figure S10).…”