Flexible Electrochromic Devices Research Articles

Hybrid Ag/Ni mesh/PH 1000 transparent electrodes for high performance flexible electrochromic devices with exceptional stability

Flexible electrochromic technology has gained numerous attentions in flexible smart wearable devices and flexible displays. For large-area flexible electrochromic devices (FECDs), highly conductive transparent electrodes with advanced stability at a prolonged redox cycling process are indispensable. In this work, a silver (Ag)/nickel (Ni) mesh/PH 1000 hybrid transparent film were successfully fabricated by selectively electrodepositing an 800 nm-thick dense metallic Ni layer and coating PH 1000 on an embedded Ag mesh to improve its electrochemical stability. The prepared hybrid transparent film presented high conductivity with a sheet resistance of below 1.5 Ω sq−1 at over 80% optical transmittance. The Ag/Ni mesh/PH 1000 was successfully utilized as current collectors for all-solid-state FECDs, showing fast coloration switching with a bleaching/coloring time of 0.7 s/0.9 s. In addition, the device demonstrated an exceptional electrochemical cycling stability, which could sustain 89% of its initial optical modulation after 25 000 cycles. More importantly, a remarkable mechanical durability was also achieved with a small optical modulation decay of 15% and an invariable response time after 1000 rolling cycles. In addition, uniform coloration were realized on a 6 × 6 cm2 FECD, demonstrating its great potential for applications of next-generation up-scaling FECDs.

All-in-One plasticized Ionogel-based stretchable electrochromic devices

While all-in-one electrochromic devices (ECDs) have attracted attention for application in wearable stretchable electronics, electrochromic materials today are unstretchable, water-vulnerable, and prone to electrolyte leakage. To address this issue, water-resistive, leakage-free, transparent, and stretchable all-in-one plasticized electrochromic ionogels (pECIonogels) are prepared. The optimized pECIonogels are used to build flexible and stretchable ECDs. The fabricated ECDs exhibit high transmittance contrast (96.8% ΔT), rapid switching time (tc,90% = 7 s, tb,90% = 19 s), and high effective coloration efficiency (285.56 cm2 C−1) at 607 nm under an applied bias voltage of −1.0 V. Moreover, the flexible ECDs show good stability even upon compressive and tensile bending. A stretchable ECD was also fabricated by directly coating Ag nanowires on the pECIonogel through a water-assisted pre-strain method. The stretchable ECD at 50% tensile strain shows lower transmittance contrast (36.0% ΔT), slower coloration/bleaching switching (tc,90% = 222 s, tb,90% = 178 s), and reduced effective coloration efficiency (226.67 cm2 C−1) than the unstretched ECD. Nevertheless, the stretchable ECDs are stable in the relaxed and colored states after being stretched, twisted, and folded. Therefore, the proposed all-in-one pECIonogel-based ECDs are promising for the development of next-generation stretchable, wearable, and implantable electronics.

P(AMPS‐co‐PEGMA)‐doped and PVDF‐HFP‐enhanced stretchable polymer electrolytes: application as flexible electrochromic devices

AbstractPolymer electrolytes are being considered as an effective solution for electrochemical devices to replace currently used organic liquid electrolytes due to their excellent mechanical properties and security. Herein, we prepared stretchable polymer electrolytes (SPEs) doped with poly[(2‐acrylamido‐2‐methylpropanesulfonic acid)‐co‐poly(ethylene glycol) dimethacrylate] (P(AMPS‐co‐PEGMA)) and enhanced with poly[(vinylidene fluoride)‐co‐hexafluoropropylene] (PVDF‐HFP), through UV in situ polymerization. The SPEs showed good mechanical performance with an elongation of more than 40% and ionic conductivity reaching the order of 10−3 S cm−1. In terms of application, flexible electrochromic devices based on the UV in situ‐prepared SPEs were assembled, the color switching performance being still good even after 400 switching cycles and 1000 bending cycles, which indicated that the SPEs could have excellent prospects in application for flexible devices. © 2023 Society of Industrial Chemistry.

Flexible Electrochromic Device on Polycarbonate Substrate with PEDOT:PSS and Color-Neutral TiO2 as Ion Storage Layer.

Electrochromic (EC) windows on glass for thermal and glare protection in buildings, often referred to as smart (dimmable) windows, are commercially available, along with rearview mirrors or windows in aircraft cabins. Plastic-based applications, such as ski goggles, visors and car windows, that require lightweight, three-dimensional (3D) geometry and high-throughput manufacturing are still under development. To produce such EC devices (ECDs), a flexible EC film could be integrated into a back injection molding process, where the films are processed into compact 3D geometries in a single automized step at a low processing time. Polycarbonate (PC) as a substrate is a lightweight and robust alternative to glass due to its outstanding optical and mechanical properties. In this study, an EC film on a PC substrate was fabricated and characterized for the first time. To achieve a highly transmissive and colorless bright state, poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) was used as the working electrode, while titanium dioxide (TiO2) was used as the counter electrode material. They were deposited onto ITO-coated PC films using dip- and slot-die coating, respectively. The electrodes were optically and electrochemically characterized. An ECD with a polyurethane containing gel electrolyte was investigated with regard to optical properties, switching speed and cycling behavior. The ECD exhibits a color-neutral and highly transmissive bright state with a visible light transmittance of 74% and a bluish-colored state of 64%, a fast switching speed (7 s/4 s for bleaching/coloring) and a moderately stable cycling behavior over 500 cycles with a decrease in transmittance change from 10%to 7%.

Solid‐State and Flexible Black Electrochromic Devices Enabled by Ni‐Cu Salts Based Organohydrogel Electrolytes

AbstractSolid‐state black electrochromic devices (ECDs) are promising for smart window applications, particularly when privacy protection and low leakage are required. Herein, a Ni–Cu salts/poly(vinyl alcohol) based organohydrogel electrolyte is developed with superior visible‐light transparency (83.8%), ionic conductivity (0.11 mS cm−1), and mechanical properties (tensile strength: 11.1 kPa, breaking strain: 242.6%). Due to the high viscosity of the organohydrogel electrolyte, a homogeneous Ni–Cu alloy film with a surface roughness of around 11.2 nm can be electrodeposited under −3 V for 5 min, and the resulting black color can be retained for over 350 min with a transmittance increase of only 5% at the voltage‐off state. The solid‐state rigid ECD exhibits an outstanding optical contrast between the transparent and colored states (visible light transmittance: 70.8% vs 0.085%), excellent cycling stability with over 90% retention of optical contrast after 2000 cycles. Finally, a flexible ECD is fabricated with the organohydrogel electrolyte and annealed indium tin oxide (ITO)‐coated polyethylene naphthalate (PEN) films as flexible and durable electrodes. It exhibits good mechanical flexibility with transmittance modulation degradation of 10% after 800 bending cycles and switching stability for 400 cycles with up to 43% optical contrast.

Five-state flexible dynamic windows

Flexible electrochromic (EC) devices are highly desirable in smart applications. Although flexible devices with up to three states have been demonstrated in previous work, the goal of EC device with characteristics of the multistate property, flexible compatibility, fast switching speed is still hard to achieve. In this work, we successfully developed a five-state flexible dynamic window (FFDW) based on Bi and Cu bimetal reversibly deposited system. This device possesses transparent state, gray state, black state, cupreous mirror state and silvery mirror state via a precise voltage control strategy. More excitingly, the phenomenon of two mirror states obtained in one device is firstly reported. This FFDW, which can be bended for more than 50 times, exhibits fast switching speed of 2.34 s for complete stripping and 11.12 s for tinting, with a more than 63% transmittance modulation range at black state and an over 60% reflectance modulation range at mirror state. Finally, we unveiled the mechanism accounting for the voltage-dependent rich optical states in details. Our findings are helpful for developing high-performance dynamic windows for application in smart homes, vehicles and wearable devices.

Large-Area Flexible Electrochromic Devices with High-Performance and Low-Power Consumption Enabled by Hydroxyhexyl Viologen-Substituted Polyhedral Oligomeric Silsesquioxane

In this work, we prepared octa-hydroxyhexyl viologen-substituted polyhedral oligomeric silsesquioxane (OHHV-POSS) as an organic–inorganic composite material applicable for large-area flexible electrochromic devices (FECDs). The organic–inorganic hybrid structure supported by the POSS cage and the enhanced interaction between hydroxyl end-groups and lithium salts can effectively increase the ionic conductivity of the ion gel films, thereby improving the electrochromic performance capabilities. Homogeneous ion gel was obtained with polyvinyl butyral and a lithium salt, and outstanding electrochromic properties were observed during electrochromic device operations. The FECDs of various sizes were fabricated for systematic evaluation, and the device of up to 22.5 × 19.5 cm2 was successfully constructed using the simple doctor blade coating method. The prepared large-area FECDs achieved a large transmittance difference of 70.0% at 604 nm, fast switching times of 21.1 and 18.0 s, high coloration efficiency of 260.61 cm2/C, long-term cycling stability of up to 300 cycles, and low power consumption of about 250 μW/cm2. Furthermore, the device was maintained stably in various application tests for heat insulation and storage, UV resistance, and mechanical stability. High performance and low power consumption of OHHV-POSS prove suitable for large-area FECDs, suggesting promising potential for smart windows, wristbands, and eyewear products.

A polyacrylic acid/polyacrylamide-based hydrogel electrolyte containing gelatin for efficient electrochromic device with outstanding cycling stability and flexible compatibility

Hydrogel electrolytes have been attracted intense research interest due to their widespread applications in advanced electronic devices. In this work, we developed a new hydrogel electrolyte to overcome two critical issues in electrochromic devices, involving long-term cycling stability and flexible compatibility. Briefly, gelatin was introduced into a hydrogel polymer matrix based on polyacrylic acid/polyacrylamide, resulting in high transparency, high electronic conductivity, durable electrochemical stability, inherent adhesiveness. Complementary electrochromic devices employing the present hydrogel electrolyte exhibited efficient performance with high optical contrast over 85 %, short response time, high coloration efficiency of 205.7 cm2/C. Remarkably, an excellent operation stability was achieved with less than 3 % loss of the initial optical contrast after 15,000 cycles switching, which was the best case among those based on the same electrochromic materials reported so far. Moreover, the efficient adhesiveness of the present hydrogel electrolyte enabled the compatibility with flexible device and improved the device bending stability. These findings might shed light on the development of durable and flexible electrochromic devices toward practical application.

Photochemical Precharging of Tungsten Trioxide for Enhanced Transmittance Modulation in Flexible Electrochromic Devices

AbstractUV irradiation is used to precharge sputtered tungsten trioxide (WO3) on polyethylene terephthalate enhancing the photochromic response with organic solvents. A comparison between the optical and electrochemical properties of photochemically and electrochemically charged WO3 results in a correlation of the transmittance to the respective charge density. This allows for a precise control of the charge density in the precharging process monitored by UV–Vis spectroscopy. A proof‐of‐concept flexible electrochromic device combining precharged WO3 (charge density: 20 mC cm−2) and Prussian blue (15 mC cm−2) exhibits a superior change in the visible light transmittance (τv) from 8% (dark) to 79% (bleached) and a coloration efficiency of 139 cm2 C−1 at 716 nm.

Multifunctional smart window based on transparent embedded Ni-mesh electrodes

Flexible electrochromic devices (ECDs) are a future technology with huge impact on wearable displays, energy saving, and adaptive camouflage. In this work, we used embedded nickel (Ni) mesh transparent electrodes combined with a thin polymer film of poly(3,4-ethylenedioxythiophene): polystyrene sulfonate (PEDOT:PSS) to build a multifunctional flexible electrochemical device that integrates the functions of electrochromic and supercapacitor devices. The multi-layer architecture improves the device performance in terms of optical contrast and mechanical strength. Ni-mesh electrodes have a high optical transparency (84.8%), good mechanical flexibility, and low resistance (0.5 Ω/sq), which is conducive to efficient electron injection, benefiting to the response time of the constructed device. The thin polymer film of PEDOT:PSS is an electrochromic (EC) material that also uniformly distributes electrons for a uniform coloration. The fabricated device shows fast response to coloring and bleaching (1.2 and 0.8 s, respectively), an absolute transmittance contrast ratio of 40%, and area capacitance of up to 2.48 mF/cm2. Furthermore, the device exhibits excellent flexibility, and the electrochromic and electrochemical properties of the device are only partially diminished upon folding, which is beneficial for the construction of multifunctional flexible electrochromic devices. With its response time, working stability, and bending ability, our multifunctional device paves the way for the next generation of flexible electronics.

Flexible Electrochromic Organic Nanofilms (FEON) Applied in Civil Construction

Flexible Electrochromic Organic Nanofilms (FEON) have drawn intense attention due to their advantages over competing technologies. The method utilized to deposit as well as to integrate solutions and processed materials, manufacturing electrochromic organic nanofilms by the Electrodeposition System, has been presented in this research. The FEON device constructed in this work is electrochromic device are the base Poly (3,4-ethylenedioxythiophene), PEDOT:PSS, Poly(3-hexyl thiophene, P3HT, Phenyl-C61-butyric acid methyl ester, PCBM, Vanadium Pentoxide, V<sub>2</sub>O<sub>5</sub>, Lithium Perchlorate, LiClO4 in Propylene Carbonate, PC and Polyaniline-X1, PANI-X1, that were deposited in Indium Tin Oxide, ITO, and characterized by Electrical Measurements and Scanning Electron Microscopy (SEM). In addition, the thin film obtained by the deposition of PANI, prepared in perchloric acid solution, was identified through PANI-X1. The maximum process temperature was 50°C, which corresponds to the baking of the active polymeric layer. The result obtained by electrical Measurements has demonstrated that the PET/ ITO/PEDOT:PSS/P3HT:PCBM-Blend/V<sub>2</sub>O<sub>5</sub>/LiClO<sub>4</sub>/ PANI-X1/ITO/PET layer presents the characteristic curve of standard electrochromic organic device after spin-coating and electrodeposition. The Thin film obtained by electrodeposition of PANI-X1 on ITO/PET Blend was prepared in perchloric acid solution. The spectrum absorption in the spectral region of 200-1100 nm of the flexible electrochromic organic nanofilm device indicated that the gradual increase of ddp of 0.0 Volt to 5.0 Volt generates a greater deviation in the optical spectral region between 450-850 nm. The thermal effects from ultraviolet irradiation under the device’s surface, in the irradiation simulator chamber, demonstrated a 5% reduction in the device’s lifetime. The inclusion of the PANI-X1 layer reduced the effects of degradation these electrochromic organic nanofilms induced for solar irradiation, a fact that also observed in the irradiation in the simulation chamber. In Scanning Electron Microscopy (SEM) these studies reveal that the surface of PANI-X1 layers is strongly conditioned by the surface morphology of the dielectric.

Implementation of high-performance flexible electrochromic device based on polyaniline/ carbon quantum dots

Implementation of high-performance flexible electrochromic device based on polyaniline/ carbon quantum dots

Ultrathin flexible electrochromic devices enabled by highly transparent ion-conducting films

A novel ion conducting film (ICF) and multicolor PANI electrochromic material were exploited for ultrathin and flexible electrochromic devices.

A self-healing polyacrylic acid-based hydrogel electrolyte for flexible quasi-solid-state electrochromic device

Due to the demand for healing damages caused during applications, it is desired to develop self-healing hydrogel electrolytes for flexible electrochromic device (ECD). A hydrogel electrolyte with remarkable self-healing ability, outstanding stretchability, and high ionic conductivity is presented in this work. Non-covalent interactions such as ionic connections between Ca 2+ and -COO - , as well as numerous hydrogen bonds between PAA and HPMC, form dynamically cross-linked PAA-HPMC-Ca hydrogel electrolytes. Owing to the exceptional reversibility of non-covalent interactions, the hydrogel electrolyte exhibits remarkable self-healing and durability. Fracture strain and stress in the self-healed PAA-HPMC-Ca hydrogel can reach 429% and 240 KPa, respectively. In addition, a flexible ECD based on PAA-HPMC-Ca hydrogel electrolyte and a WO 3 electrochromic layer was assembled and evaluated. The flexible quasi-solid-state ECD possesses excellent modulation transmittance range (approximately 66%), high coloration efficiency and steady response time. Thanks to the stability of the PAA-HPMC-Ca hydrogel electrolyte, the flexible ECD exhibits a great stability over 1000 cycles. This study may pave the way for self-healing electrolyte gels to be used in ECDs, supercapacitors, and batteries, among other flexible electrochemical devices. • A hydrogel electrolyte with self-healing ability is fabricated via facile methods. • Fracture strain and stress in self-healed hydrogel can reach 429% and 240 KPa. • Hydrogel electrolytes have high ionic conductivity and wide electrochemical window. • A quasi-solid-sate ECD based on PAA-HPMC-Ca hydrogel electrolyte is assembled. • Quasi-solid-sate ECD retains excellent electrochromic performance after 1000 cycles.

Optimization of oxide materials in oxide-metal-oxide(OMO) electrodes for flexible electrochromic devices

The use of the oxide-metal-oxide (OMO) structure is one of the key strategies for enhancing the sheet resistance and flexibility of large-area flexible displays. Various combinations of OMOs with indium-tin oxide (ITO) and zinc-tin oxide (ZTO) for the oxide layer and a metal layer with silver (Ag) are discussed. Four-types of OMO are fabricated and the electrical characteristics of each are confirmed through electrochromic devices. The type of oxide layer affects the electron transfer from the metal layer to the oxide layer. Thus, the position of the oxide layer depends on the band structure and should be considered to achieve better performance. The ITO/Ag/ITO (IAI) type of electrode demonstrated the lowest sheet resistance at an average of 8 Ω sq −1 as well as high transparency above 80% at a wavelength of 650 nm. Electrochromic transparency differences between the bleached and colored states were maintained at 52.1% after 200 cycles, and the times required for coloration and bleaching were 0.5s and 8.1s, respectively. A stable redox reaction was confirmed after storing the devices at −30 °C and 85 °C for 18 h. • Fabrication of various OMO electrodes for flexible electrochromic devices is possible. • Relationship between the top-layer and bottom-layer of OMO electrode are investigated. • Flexible large-area electrochromic devices are tested within long-term cycles and harsh temperature.

Bifunctional flexible electrochromic energy storage devices based on silver nanowire flexible transparent electrodes

Flexible electrochromic energy storage devices (FECESDs) for powering flexible electronics have attracted considerable attention. Silver nanowires (AgNWs) are one kind of the most promising flexible transparent electrodes (FTEs) materials for the emerging flexible devices. Currently, fabricating FECESD based on AgNWs FTEs is still hindered by their intrinsic poor electrochemical stability. To address this issue, a hybrid AgNWs/Co(OH)2/PEDOT:PSS electrode is proposed. The PEDOT:PSS could not only improve the resistance against electrochemical corrosion of AgNWs, but also work as functional layer to realize the color-changing and energy storage properties. Moreover, the Co(OH)2 interlayer further improved the color-changing and energy storage performance. Based on the improvement, we assembled the symmetrical FECESDs. Under the same condition, the areal capacitance (0.8 mF cm−2) and coloration efficiency (269.80 cm2 C−1) of AgNWs/Co(OH)2/PEDOT:PSS FECESDs were obviously higher than AgNWs/PEDOT:PSS FECESDs. Furthermore, the obtained FECESDs exhibited excellent stability against the mechanical deformation. The areal capacitance remained stable during 1000 times cyclic bending with a 25 mm curvature radius. These results demonstrated the broad application potential of the AgNWs/Co(OH)2/PEDOT:PSS FECESD for the emerging portable and multifunctional electronics.

Ultra-strong ionic liquid-based polymer composite electrolyte for high performance electrochromic devices

Polymer electrolytes are the key composite for all-solid electrochromic devices due to their unique properties including high ionic conductivity, good flexibility, etc. However, such applications are still impeded by the poor mechanical strength. In this study, novel quasi-solid polymer/ionic liquid composite electrolyte is constructed and the tensile strength is greatly enhanced by coupling epoxy composite with glass fibers (GFs) as the reinforcement. The tensile strength of the composite electrolyte is tripled and reaches 7.6 MPa after optimizing the content of GFs with the ionic conductivity of 1.75 × 10 −5 S cm −1 . Then, a dual-coloring electrochromic device fabricated with the composite electrolyte presents excellent switching stability (18000 cycles, >180000 s), fast response (˂2 s), ultra-high coloring efficiency (η = 451 cm 2 /C) and low driving voltage (±1 V). In addition, a substrate-free and flexible electrochromic device based on the composite electrolyte is successfully assembled, which demonstrates remarkable electrochromic behaviors, unique flexibility and mechanical stability. This work may promote the development of low-cost, easily-assembled, ultrahigh-flexible and high-performance electrochromic devices. • A ultra-strong composite electrolyte is fabricated by introducing glass fibers into the polymer matrix. • A electrochromic device based on the composite electrolyte demonstrates high optical contrast, fast switching response, and high color efficiency. • The high strength of the composite electrolyte make it possible to construct substrate-free and cost-effective ECDs.

Toward High-Performance Electrochromic Conjugated Polymers: Influence of Local Chemical Environment and Side-Chain Engineering

Three homologous electrochromic conjugated polymers, each containing an asymmetric building block but decorated with distinct alkyl chains, were designed and synthesized using electrochemical polymerization in this study. The corresponding monomers, namely T610FBTT810, DT6FBT, and DT48FBT, comprise the same backbone structure, i.e., an asymmetric 5-fluorobenzo[c][1,2,5]thiadiazole unit substituted by two thiophene terminals, but were decorated with different types of alkyl chain (hexyl, 2-butyloctyl, 2-hexyldecyl, or 2-octyldecyl). The effects of the side-chain structure and asymmetric repeating unit on the optical absorption, electrochemistry, morphology, and electrochromic properties were investigated comparatively. It was found that the electrochromism conjugated polymer, originating from DT6FBT with the shortest and linear alkyl chain, exhibits the best electrochromic performance with a 25% optical contrast ratio and a 0.3 s response time. The flexible electrochromic device of PDT6FBT achieved reversible colors of navy and cyan between the neutral and oxidized states, consistent with the non-device phenomenon. These results demonstrate that subtle modification of the side chain is able to change the electrochromic properties of conjugated polymers.

Ultra‐Low Resistivity Copper Mesh as Embedded Current Collector Layer for Inkjet‐Printed Flexible Electrochromic Device Realizing Fast Response and Uniform Coloration

AbstractFlexible electrochromic devices (FECDs) hold great promise for energy‐saving static displays. As the most widely used flexible transparent electrode (FTE) material for FECDs, the indium tin oxide (ITO) coated on polyethylene terephthalate (PET‐ITO) suffers from relatively high sheet resistance which can cause nonuniform coloration during the device operation, hindering the development of large‐area FECDs. Herein, a hybrid FTE is developed in which an additional copper (Cu) mesh as an embedded current collector layer underneath the ITO film to achieve ultra‐low sheet resistance (<0.2 Ω □−1) compared to that of PET‐ITO (≈35 Ω □−1). The figure of merit (FoM) of the fabricated Cu mesh‐ITO is calculated to be 9500, nearly 200 times better than that of PET‐ITO. A binary‐solvent ink of electrochromic polymer (ECP‐magenta) is also developed to realize the patterning of FECDs via the inkjet‐printing method. Consequently, the inkjet‐printed FECD exhibits a fast response (≤1.2/1.9 s for coloration/bleaching) and excellent stability (less than 15% degradation after 50 000 switching cycles). In addition, uniform coloration is realized within 1 s on a 10 × 10 cm2 large size FECD, indicating great promise for Cu mesh‐ITO as a new FTE material to replace PET‐ITO for large‐area FECDs.

Rapidly Photocurable Solid-State Poly(ionic liquid) Ionogels For Thermally Robust and Flexible Electrochromic Devices.

Formation of ionogels through in situ polymerization can effectively improve electrolyte processability; however, the curing process has been slow and oxygen-sensitive. Considering the low oxygen solubility of poly(ionic liquid)s (PILs), in situ polymerized ionogels are designed to realize excellent electrolytes. Herein, two in situ polymerized ionogels (PIL A & PIL B) are formulated, and they can be rapidly photocured within a minute. The ionogels are highly transparent, stretchable, and exhibit excellent physicochemical stability, including thermal, electrochemical, and air stability, allowing them to perform in various conditions. Benefitting from these properties, two high-performance electrochromic devices (ECDs) are assembled, with iron-centered coordination polymer (FeCP) and tungsten oxide (P-WO3 ) electrochromic materials, achieving high color contrast (45.2% and 56.4%), fast response time (1.5/1.9 and 1.7/6.4 s), and excellent cycling endurance (>90% retention over 3000 cycles). Attributed to the thermal robustness of the ionogels, the ECDs can also be operated over a wide temperature range (-20 to 100 °C). With the use of deformable substrates (e.g., ultrathin ITO glass), curved electrochromic eye protector and flexible electrochromic displays are realized, highlighting their potential use in futuristic wearables.