Video‐Rate Switching of High‐Reflectivity Hybrid Cavities Spanning All Primary Colors

Abstract

Dynamically tunable reflective structural colors are attractive for reflective displays (electronic paper). However, it is challenging to tune a thin layer of structural color across the full red–green–blue (RGB) basis set of colors at video rates and with long‐term stability. In this work, this is achieved through a hybrid cavity built from metal–insulator–metal (MIM) “nanocaves” and an electrochromic polymer (PProDOTMe2). The reflective colors are modulated by electrochemically doping/dedoping the polymer. Compared with traditional subpixel‐based systems, this hybrid structure provides high reflectivity (>40%) due to its “monopixel” nature and switches at video rates. The polymer bistability helps deliver ultralow power consumption (≈2.5 mW cm−2) for video display applications and negligible consumption (≈3 µW cm−2) for static images, compatible with fully photovoltaic powering. In addition, the color uniformity of the hybrid material is excellent (over cm−2) and the scalable fabrication enables large‐area production.

Switchable Broadband Terahertz Absorbers Based on Conducting Polymer‐Cellulose Aerogels

“…To our knowledge, this is the largest achieved modulation capability for broadband THz transmission materials reported to date. Future developments will benefit from the ability to also switch conducting polymer systems by electrical potentials, [36,81] even at videorates, [39,64,65] which further strengthens the relevance of these materials for practical applications. In addition, we demonstrate modification of surface hydrophilicity and deicing and de-frosting properties of the aerogels, further improving their suitability for practical applications.…”

“…Future research may therefore focus on implementing other tuning modalities, and it is promising that conducting polymer systems have shown compatibility with electrical tuning at video rates. [64,65] We further note that not all applications require fast switching, so the current materials may find use in practical applications, for example, for low-speed tunable attenuators to modulate the light intensity of THz sources. In addition, our aerogels provide a good optical memory effect, where the state of the aerogels is nonvolatile, which is also an attractive property for many applications (Figures S18 and S19, Supporting Information).…”

Electrochromic Passive Matrix Display Utilizing Diode‐Like Redox Reactions on Indium‐Tin‐Oxide

“…This, in turn, means that the switch time of the electrochromic material becomes important for arrays with many pixels and may directly determine how many rows can be included in practice. Thus, passive matrix operation is likely suitable for organic electrochromism where switching can be made fast, [ 5,6,20 ] but could be more challenging to get to work with inorganic electrochromic materials, which typically switch an order of magnitude slower. [ 24 ]…”

“…Recently, the challenge of improving electronic paper in color has been addressed by various combinations of electrochromic materials and structural colors, [ 3,4 ] aiming to improve vibrance, brightness (reflectance), and contrast. While several significant advances have been made, including even video speed operation, [ 5,6 ] a requirement for a display device to show an arbitrary image is that the display is pixelated (not just segmented) into a 2D matrix with individual pixel addressability. Although a few examples have been presented, [ 7,8 ] the question of how to realize pixelated devices with structural colors has been somewhat overlooked.…”

pH-Responsive, Wide Color Gamut Dynamic Color Display Enabled by PDMAEMA Brush-Based Fabry–Perot Resonant Cavity

“…Structural color originating from the interaction of certain nanostructures and visible light has attracted great interest. − Compared to conventional color based on chemical pigments or organic dyes, structural color materials involve several prominent advantages including high spatial resolution, excellent structure stability, and environmentally friendliness, and thus can be utilized in various application fields such as color printing, color display, and decoration. ,− Dynamic color-changing materials, known as an important branch of structural color materials, possesses multiple advanced functionalities and wonderful color-changing capabilities in response to external stimuli, which exist extensively in nature. − One of the most typical example is chameleons, who change their structural colors dynamically in response to the color change of the surrounding environment by actively tuning the lattice spacing of small guanine nanocrystals in iridophores . As a deep understanding of definite relationship between structural color and nanostructures is achieved, scientists try to mimic such responsive behaviors in nature and begin to design various dynamic color-changing materials due to their potential applications in visual sensing, − dynamic color display, − anticounterfeiting, − image encryption/decryption, ,, etc. In the area of dynamic color-changing materials, photonic crystals, and plasmonic nanostructures have been extensively explored through integrating stimuli-responsive material into their intrinsic structure or interstice structure. ,− However, toward further practical applications of such materials, both of these two typical systems consist of complex constructions and suffer from time-consuming and complicated manufacturing processes.…”