The engineering of optical and acoustic material functionalities via construction of ordered local and global architectures on various length scales commensurate with and well below the characteristic length scales of photons and phonons in the material is an indispensable and powerful means to develop novel materials. In the current mature status of photonics, polymers hold a pivotal role in various application areas such as light-emission, sensing, energy, and displays, with exclusive advantages despite their relatively low dielectric constants. Moreover, in the nascent field of phononics, polymers are expected to be a superior material platform due to the ability for readily fabricated complex polymer structures possessing a wide range of mechanical behaviors, complete phononic bandgaps, and resonant architectures. In this review, polymer-centric photonic and phononic crystals and metamaterials are highlighted, and basic concepts, fabrication techniques, selected functional polymers, applications, and emerging ideas are introduced.

We report green emission from a single-layer device based on the ionic transition metal complex [Ir(F-mppy)2(dtb-bpy)]+(PF6−), where F-mppy is 2-(4′-fluorophenyl)-5-methylpyridine and dtb-bpy is 4,4′-di-tert-butyl-2,2′bipyridine. External quantum efficiencies of up to 1.1% are achieved with air-stable contacts, and up to 1.8% with a CsF∕Al top contact. Addition of the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate was found to improve the device response time and cause a bias-dependent shift in the emission spectrum. As a result, electroluminescence was observed at 531 nm (CIE coordinates: 0.3230 and 0.5886), the lowest wavelength reported to date for a device based on ionic transition metal complexes.

We report a fully reversible and robust shape-memory effect in a two-dimensional nanoscale periodic structure composed of three steps, the elastic instability governing the transformation, the plasticity that locks in the transformed pattern as a result of an increase in glass transition temperature (T(g)), and the subsequent elastic recovery due to the vapor-induced decrease in T(g). Solvent swelling of a cross-linked epoxy/air cylinder structure induces an elastic instability that causes a reversible change in the shape of the void regions from circular to oval. The pattern symmetry changes from symmorphic p6mm to nonsymmorphic p2gg brought via the introduction of new glide symmetry elements and leads to a significant change in the phononic band structure, specifically in the opening of a new narrow-band gap due to anticrossing of bands, quite distinct from gaps originating from typical Bragg scattering. We also demonstrate that numerical simulations correctly capture the three steps of the shape-memory cycle observed experimentally.