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Luminescence is an essential signal for many plants, insects, and marine organisms to attract the opposite sex, avoid predators, and so on. Most luminescent living organisms have ingenious optical structures which can help them get high luminescent performances. These remarkable and efficient structures have been formed by natural selection from long-time evolution. Researchers keenly observed the enhanced luminescence phenomena and studied how these phenomena happen in order to learn the characteristics of bio-photonics. In this review, we summarize the optical structures for enhancing luminescence and their applications. The structures are classified according to their different functions. We focus on how researchers use these biological inspirations to enhance different luminescence processes, such as chemiluminescence (CL), photoluminescence (PL), and electroluminescence (EL). It lays a foundation for further research on the applications of luminescence enhancement. Furthermore, we give examples of luminescence enhancement by bio-inspired structures in information encryption, biochemical detection, and light sources. These examples show that it is possible to use bio-inspired optical structures to solve complex problems in optical applications. Our work will provide guidance for research on biomimetic optics, micro- and nano-optical structures, and enhanced luminescence. [ABSTRACT FROM AUTHOR]

Flexible free-standing one-dimensional photonic crystals (1DPCs) have attracted tremendous attentions owing to the simplest structure and promising applications in various fields. However, that most of flexible 1DPCs need dozens of stacks to achieve excellent optical properties and weak robustness in extreme environments hinder their practical applications. Herein, we prepare a series of robust, flexible free-standing polyimide (PI)/SiOx nanocomposite 1DPCs by solution process. Inorganic SiOx with low refractive index (n) is derived from the precursor perhydropolysilazane (PHPS) while the super-engineering plastic PI is served as the high-refractive-index constitution. Thanks to the high refractive index contrast (Δn) and uniform micromorphology of both materials, vivid PI/SiOx 1DPCs with tunable photonic bandgap are obtained and the reflectance is high up to 97% within only 9 layers. Due to the intrinsic properties and covalent binding between PI and SiOx layers, the free-standing nanocomposite remains stable in the wide range of – 196–200 °C and has no degradation of optical performance after bending deformation for 500 times. Additionally, PI/SiOx 1DPCs show great resistance to organic solvent, acid solution and ultraviolet (UV) radiation. Therefore, it is envisioned that the flexible free-standing PI/SiOx 1DPCs have great potential for applications in harsh environment. [ABSTRACT FROM AUTHOR]

Solution-processed, high-gain, and wavelength-tunable perovskite single-crystal microdisk (PVKsc-MD) lasers have emerged as prospective coherent light sources in advanced nanophotonic designs. However, the inevitable multi-directional emission from a highly symmetrical cavity leads to low light collection efficiency which greatly hinders its application in integrated optical circuits. Here, we report on surface-patterned MAPbBr 3 PVKsc-MDs synthesized by a cost-efficient bottom-up solution process employing spin-coating and confined-growth nanoimprinting. The patterned microdisks have high crystal quality with regular shape and sharp edges and nano-grating structure on the upper surface. This straightforward process yields surface-patterned PVKsc-MD lasers with a low lasing threshold and high quality (Q) factor. In addition, the grating structure patterned on the PVKsc-MDs reduces the original symmetry of the laser cavity, which improves the emission directionality four times., (© 2022 Wiley-VCH GmbH.)