Programmable Invisible Photonic Patterns with Rapid Response Based on Two-Dimensional Colloidal Crystals

Recent Progress in Responsive Structural Color

Structural color has been regarded as an ideal alternative to pigments because of the advantages of environmental friendliness, resistance to fading, and dynamic regulation. Responsive structural color can give real-time visible feedback to external stimuli and thus has great prospects in many applications, such as displays, sensing, anticounterfeiting, information storage, and healthcare monitoring. In this Perspective, we elucidate basic concepts, controllable fabrications, and promising applications of responsive structural colors. In particular, we systematically summarize the general regulation mode of all kinds of responsive structural color systems. First, we introduce the basic chromogenic structures as well as the regulation modes of responsive structural color. Second, we present the fabrication methods of patterned structural color. Then, the promising applications of responsive structural color systems are highlighted in detail. Finally, we present the existing challenges and future perspectives on responsive structural colors.

Studies on transmittance modulation and ions transfer kinetic based on capacitive-controlled 2D V2O5inverse opal film for electrochromic energy storage application

Two-dimensional vanadium pentoxide inverse opal (2D V₂O₅IO) architecture was fabricated by polystyrene (PS) sphere template assisted electrodeposition process. In comparison to the un-templated V₂O₅film, the 2D V₂O₅IO film exhibited a highly ordered hexagonal close-packed bowel-like array, as well as noticeable electrochromism, such as transmittance modulation up to 42.6% at 800 nm, high coloration efficiency (28.6 cm² · C^-1), fast ions transfer kinetic (t_b = 7.2 s,t_c = 2.5 s). These improvements of electrochromic performance were attributed to the ordered morphology with larger surface areas, which considerably shortened the ions diffusion paths and accelerated ions migration. An electrochromic energy storage device assembled from the 2D V₂O₅IO film with simultaneous electrochromic and pseudocapacitive performance could not only show transmittance modulation accompanied by multicolor variations but also powered an LCD screen and an LED bulb, demonstrating a promising potential for practical applications.