Tailoring silicon for dew water harvesting panels

An Omnidirectional Dual-Functional Metasurface with Ultrathin Thickness

Although metasurfaces have received enormous attention and are widely applied in various fields, the realization of multiple functions using a single metasurface is still rarely reported to date. In this work, we propose a novel dual-functional metasurface that can be applied as a mid-infrared narrowband thermal light source in optical gas sensing and a long-wave infrared broadband absorber in photodetection. By actively tailoring the structure and constituent materials of the metasurface, the device yields an absorptivity of over 90% from 8 µm to 14 µm, while it exhibits an emissivity of 97.4% at the center wavelength of 3.56 μm with a full width at half-maximum of 0.41 µm. Notably, the metasurface is insensitive to the incident angle under both TM- and TE-polarized light. The proposed dual-functional metasurface possesses many advantages, including a simple structure, thin thickness, angle and polarization insensitivity, and compatibility with optical devices, which are expected to simplify the existing imaging systems and improve the performance of photodetection equipment.

Fundamentals and utilization of solid/ liquid phase boundary interactions on functional surfaces

The affinity of macroscopic solid surfaces or dispersed nano- and bioparticles towards liquids plays a key role in many areas from fluid transport to interactions of the cells with phase boundaries. Forces between solid interfaces in water become especially important when the surface texture or particles are in the colloidal size range. Although, solid-liquid interactions are still prioritized subjects of materials science and therefore are extensively studied, the related literature still lacks in conclusive approaches, which involve as much information on fundamental aspects as on recent experimental findings related to influencing the wetting and other wetting-related properties and applications of different surfaces. The aim of this review is to fill this gap by shedding light on the mechanism-of-action and design principles of different, state-of-the-art functional macroscopic surfaces, ranging from self-cleaning, photoreactive or antimicrobial coatings to emulsion separation membranes, as these surfaces are gaining distinguished attention during the ongoing global environmental and epidemic crises. As there are increasing numbers of examples for stimulus-responsive surfaces and their interactions with liquids in the literature, as well, this overview also covers different external stimulus-responsive systems, regarding their mechanistic principles and application possibilities.