Dual-band electrochromic smart windows(DESWs)with independent control of the transmittance of near-infrared and visible light show great potential in the application of smart and energy-saving buildings.The current st...Dual-band electrochromic smart windows(DESWs)with independent control of the transmittance of near-infrared and visible light show great potential in the application of smart and energy-saving buildings.The current strategy for building DESWs is to screen materials for composite or prepare plasmonic nanocrystal films.These rigorous preparation processes seriously limit the further development of DESWs.Herein,we report a facile and effective sol-gel strategy using a foaming agent to achieve porous Ti-doped tungsten oxide film for the high performance of DESWs.The introduction of foaming agent polyvinylpyrrolidone during the film preparation can increase the specific surface area and free carrier concentration of the films and enhance their independent regulation ability of near-infrared electrochromism.As a result,the optimal film shows excellent dual-band electrochromic properties,including high optical modulation(84.9%at 633 nm and 90.3%at 1200 nm),high coloration efficiency(114.9 cm^(2) C^(-1) at 633 nm and 420.3 cm^(2) C^(-1) at 1200 nm),quick switching time,excellent bistability,and good cycle stability(the transmittance modulation losses at 633 and 1200 nm were 11%and 3.5%respectively after 1000 cycles).A demonstrated DESW fabricated by the sol-gel film showed effective management of heat and light of sunlight.This study represents a significant advance in the preparation of dual-band electrochromic films,which will shed new light on advancing electrochromic technology for future energy-saving smart buildings.展开更多
Electrochromic technology has gained significant attention in various fields such as displays,smart windows,biomedical monitoring,military camouflage,human-machine interaction,and electronic skin due to its ability to...Electrochromic technology has gained significant attention in various fields such as displays,smart windows,biomedical monitoring,military camouflage,human-machine interaction,and electronic skin due to its ability to provide reversible and fast color changes under applied voltage.With the rapid development and increasing demand for flexible electronics,flexible electrochromic devices(FECDs)that offer smarter and more controllable light modulation hold great promise for practical applications.The electrochromic material(ECM)undergoing color changes during the electrochemical reactions is one of the key components in electrochromic devices.Among the ECMs,viologens,a family of organic small molecules with 1,1'-disubstituted-4,4'-dipyridinium salts,have garnered extensive research interest,due to their well-reversible redox reactions,excellent electron acceptance ability,and the ability to produce multiple colors.Notably,viologen-based FECDs demonstrate color changes in the liquid or semisolid electrolyte layer,eliminating the need for two solid electrodes and thus simplifying the device structure.Consequently,viologens offer significant potential for the development of FECDs with high optical contrast,fast response speed,and excellent stability.This review aims to provide a comprehensive overview of the progress and perspectives of viologen-based FECDs.It begins by summarizing the typical structure and recent exciting developments in viologen-based FECDs,along with their advantages and disadvantages.Furthermore,the review discusses recent advancements in FECDs with additional functionalities such as sensing,photochromism,and energy storage.Finally,the remaining challenges and potential research directions for the future of viologen-based FECDs are addressed.展开更多
In this paper,a dual-band graphene-based frequency selective surface(GFSS)is investigated and the operating mechanism of this GFSS is analyzed.By adjusting the bias voltage to control the graphene chemical po-tential ...In this paper,a dual-band graphene-based frequency selective surface(GFSS)is investigated and the operating mechanism of this GFSS is analyzed.By adjusting the bias voltage to control the graphene chemical po-tential between 0 eV and 0.5 eV,the GFSS can achieve four working states:dual-band passband,high-pass lowimpedance,low-pass high-impedance,and band-stop.Based on this GFSS,a hexagonal radome on a broadband omnidirectional monopole antenna is proposed,which can achieve independent 360°six-beam omnidirectional scanning at 1.08 THz and 1.58 THz dual bands.In addition,while increasing the directionality,the peak gains of the dual bands reach 7.44 dBi and 6.67 dBi,respectively.This work provides a simple method for realizing multi-band terahertz multi-beam reconfigurable antennas.展开更多
Functional materials may change color by heat and electricity separately or simultaneously in smart windows.These materials have not only demonstrated remarkable potential in the modulation of solar radiation but are ...Functional materials may change color by heat and electricity separately or simultaneously in smart windows.These materials have not only demonstrated remarkable potential in the modulation of solar radiation but are also leading to the development of indoor environments that are more comfortable and conducive to improving individuals'quality of life.Unfortunately,dual-responsive materials have not received ample research attention due to economic and technological challenges.As a consequence,the broader utilization of smart windows faces hindrances.To address this new generational multistimulus responsive chromic materials,our group has adopted a developmental strategy to create a poly(NIPAM)n-HV as a switchable material by anchoring active viologen(HV)onto a phase-changing poly(NIPAM)n-based smart material for better utility and activity.These constructed smart windows facilitate individualistic reversible switching,from a highly transparent state to an opaque state(thermochromic)and a red state(electrochromic),as well as facilitate a simultaneous dual-stimuli response reversible switching from a clear transparent state to a fully opaque(thermochromic)and orange(electrochromic)states.Absolute privacy can be attained in smart windows designed for exclusive settings by achieving zero transmittance.Each unique chromic mode operates independently and modulates visible and near-infrared(NIR)light in a distinct manner.Hence,these smart windows with thermal and electric dual-stimuli responsiveness demonstrate remarkable heat regulation capabilities,rendering them highly attractive for applications in building facades,energy harvesting,privacy protection,and color display.展开更多
The electrochromic Li-ion batteries(ELIBs) combine the functions of electrochromism and energy storage,realizing the display of energy-storage levels by visual signals. However, the accompanying interfacial issues inc...The electrochromic Li-ion batteries(ELIBs) combine the functions of electrochromism and energy storage,realizing the display of energy-storage levels by visual signals. However, the accompanying interfacial issues including physical contact and(electro)chemical stability should be taken into account when the conventional liquid/gel electrolytes are replaced with solid-state counterparts. Herein, the in-situ liquid-solid transitional succinonitrile(SCN) plastic glues are constructed between electrodes and poly(ethylene oxide)(PEO) polymer electrolytes, enabling an interface-reinforced solid-state ELIB.Specifically, the liquid SCN precursor can adequately wet electrode/PEO interfaces at high temperature,while it returns back to solid state at room temperature, leading to seamless interfacial contact and smooth ionic transfer without changing the solid state of the device. Moreover, the SCN interlayer suppresses the direct contact of PEO with electrodes containing high-valence metal ions, evoking the improved interfacial stability by inhibiting the oxidation of PEO. Therefore, the resultant solid-state ELIB with configuration of LiMn_(2)O_(4)/SCN-PEO-SCN/WO_(3) delivers an initial discharge capacity of 111 m A h g^(-1) along with a capacity retention of 88.3% after 200 cycles at 30 ℃. Meanwhile, the electrochromic function is integrated into the device by distinguishing its energy-storage levels through distinct color changes. This work proposes a promising solid-state ELIB with greatly reinforced interfacial compatibility by introducing in-situ solidified plastic glues.展开更多
In recent times,future energy storage systems demand a multitude of functionalities beyond their traditional energy storage capabilities.In line with this technological shift,there is active research and development o...In recent times,future energy storage systems demand a multitude of functionalities beyond their traditional energy storage capabilities.In line with this technological shift,there is active research and development of electrochromic-energy storage systems designed to visualize electrochemical charging and discharging processes.The conventional electrochromic-energy storage devices primarily integrated supercapacitors,known for their high power density,to enable rapid color contrast.However,the low energy density of supercapacitors restricts overall energy storage capacity,acting as a significant barrier to expanding the application range of such systems.In this review,we introduce electrochromic zinc(Zn)-ion battery systems,which effectively overcome the limitation of low energy density,and provide illustrative examples of their applicability across diverse fields.Although many recent research works are present for electrochromic Zn-ion batteries,little review has so far taken place.Our objective is to discuss on the current progress and future directions for electrochromic Zn-ion batteries,which are applicable for wearable electronics applications and energy storage systems.This review provides an initial milestone for future researchers in electrochromic energy storage and zinc-ion batteries,which will lead to a stream of future works related to them.展开更多
NiO,an anodic electrochromic material,has applications in energy-saving windows,intelligent displays,and military camouflage.However,its electrochromic mechanism and reasons for its performance degradation in alkaline...NiO,an anodic electrochromic material,has applications in energy-saving windows,intelligent displays,and military camouflage.However,its electrochromic mechanism and reasons for its performance degradation in alkaline aqueous electrolytes are complex and poorly understood,making it challenging to improve NiO thin films.We studied the phases and electrochemical characteristics of NiO films in different states(initial,colored,bleached and after 8000 cycles)and identified three main reasons for performance degradation.First,Ni(OH)_(2)is generated during electrochromic cycling and deposited on the NiO film surface,gradually yielding a NiO@Ni(OH)_(2)core-shell structure,isolating the internal NiO film from the electrolyte,and preventing ion transfer.Second,the core-shell structure causes the mode of electrical conduction to change from first-to second-order conduction,reducing the efficiency of ion transfer to the surface Ni(OH)_(2)layer.Third,Ni(OH)_(2)and NiOOH,which have similar crystal structures but different b-axis lattice parameters,are formed during electrochromic cycling,and large volume changes in the unit cell reduce the structural stability of the thin film.Finally,we clarified the mechanism of electrochromic performance degradation of NiO films in alkaline aqueous electrolytes and provide a route to activation of NiO films,which will promote the development of electrochromic technology.展开更多
The current investigation offers an innovative synthetic solution regarding electrochromic(EC)and energy storage applications by exploring phenoxazine(POZ)moiety.Subsequently,three POZ-based polymers(polyimide,polyazo...The current investigation offers an innovative synthetic solution regarding electrochromic(EC)and energy storage applications by exploring phenoxazine(POZ)moiety.Subsequently,three POZ-based polymers(polyimide,polyazomethine,and polyamide)were synthesized to ascertain the superior performer.The polyamide exhibited remarkable attributes,including high redox stability during 500 repetitive CVs,optical contrast of 61.98%,rapid response times of 1.02 and 1.38 s for coloring and bleaching,EC efficiency of 280 cm^(2)C^(-1).and decays of the optical density and EC efficiency of only 12.18%and 6.23%after 1000 cycles.Then,the energy storage performance of polyamide PA was tested,for which the following parameters were obtained:74.7 F g^(-1)(CV,scan rate of 10 mV s^(-1))and 118 F g^(-1)(GCD,charging current of 0.1 A g^(-1)).Then,the polyamide was tested in EES devices,which yielded the following EC parameters:an optical contrast of 62.15%,response times of 9.24 and 5.01 s for coloring and bleaching,EC efficiency of 178 cm^(2)C^(-1),and moderate decays of 20.25%and 23.24%for the optical density and EC efficiency after 500 cycles.The energy storage performance included a capacitance of 106 F g^(-1)(CV,scan rate of 0.1 mV s^(-1))and 9.23 F g^(-1)(GCD,charging current of 0.1 A g^(-1)),capacitance decay of 11.9%after500 cycles,and 1.7 V retention after 2 h.Also,two EES devices connected in series powered a 3 V LED for almost 30 s.展开更多
Flexible electrochromic devices (FECDs) are promising candidates for the next generation of wearable electronics due to their low operating voltage and energy consumption. For the flexible electrochromic devices, the ...Flexible electrochromic devices (FECDs) are promising candidates for the next generation of wearable electronics due to their low operating voltage and energy consumption. For the flexible electrochromic devices, the electrolyte is an important component. Typically, the electrolyte needs to be formulated according to the device structure and usage scenario. A high-performance electrolyte involves consideration of many factors, including choosing the right polymer, solvent, curing agent, and ion type to satisfy particular device specifications. In this work, a ultraviolet-curable solid–liquid host–guest (UV-SLHG) electrolyte is developed. Several aspects of performance are improved by introducing the solid–liquid coexisting microstructure without changing the electrolyte formulation, including excellent adhesion, a 30% increase in tensile characteristics, and a seven-fold increase in ionic conductivity when compared to a fully cured solid-state electrolyte. More importantly, the unique advantage of SLHG electrolytes lies that the thickness will not change significantly during bending. The FECD made by using the UV-SLHG-based electrolyte sustained 10,000 bending cycles at the bending radius of 2.5 mm while maintaining outstanding optical modulation. A wearable ring-type ECD and a battery-free FECD wine label were made as demonstrators. The UV-SLHG strategy is not only suitable for the FECDs but also universally applicable to other electrolyte-based of flexible electronics such as flexible capacitors and batteries.展开更多
Aqueous electrochromic battery(ECB)has shown intense potential for achieving energy storage and saving simultaneously.While tungsten oxide(WO_(3))is the most promising EC material for commercialization,the cycling sta...Aqueous electrochromic battery(ECB)has shown intense potential for achieving energy storage and saving simultaneously.While tungsten oxide(WO_(3))is the most promising EC material for commercialization,the cycling stability of WO_(3)-based aqueous ECBs is currently unsatisfactory due to the repeated phase transition during the redox process and the corrosion by acidic electrolytes.Herein,we present a titanium-tungsten oxide alloy(Ti-WO_(3))with controllable morphology and crystal phase synthesized by a facile hot injection method to overcome the challenges.In contrast to conventional monoclinic WO_(3),the Ti-WO_(3)nanorods can stably maintain their cubic crystal phase during the redox reaction in an acidic electrolyte,thus leading to dramatically enhanced response speed and cycling stability,Specifically,when working in a well-matched hybrid Al^(3+)/Zn^(2+)aqueous electrolyte,our phasetransition-free cubic Ti-WO_(3)exhibits an ultra-high cycling stability(>20000 cycles),fast response speed(3,95 s/4,65 s for bleaching/coloring),as well as excellent discharge areal capacity of 214.5 mA h m^(-2),We further fabricate a fully complementa ry aqueous electrochromic device,for the first time,using a Ti-WO_(3)/Prussian blue device architecture.Remarkably,the complementary ECB shows>10000 stable operation cycles,attesting to the feasibility of our Ti-WO_(3)for practical applications.Our work validates the significance of inhibiting the phase transitions of WO_(3)during the electrochromic process for realizing highly cyclable aqueous ECB,which can possibly provide a generalized design guidance for other high-quality metallic oxides for electrochemical applications.展开更多
Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)(PEDOT:PSS) is usually sandwiched between indium tin oxide(ITO) and a functional polymer in order to improve the performance of the device. However, bec...Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)(PEDOT:PSS) is usually sandwiched between indium tin oxide(ITO) and a functional polymer in order to improve the performance of the device. However, because of the strong acidic nature of PEDOT:PSS, the instability of the ITO/PEDOT:PSS interface is also observed. The mechanism of degradation of the device remains is unclear and needs to be further studied. In this article, we investigate the in-situ electrochromism of PEDOT:PSS to disclose the cause of the degradation. X-ray photoelectron spectroscopy(XPS) was used to characterize the PEDOT:PSS films, as well as the PEDOT:PSS plus polyethylene glycol(PEG) films with and without indium ions. The electrochromic devices(ECD) based on PEDOT:PSS and PEG with and without indium ions are carried out by in-situ micro-Raman and laser reflective measurement(LRM). For comparison, ECD based on PEDOT:PSS and PEG films with LiCl, KCl, NaCl or InCl_3 are also investigated by LRM. The results show that PEDOT:PSS is further reduced when negatively biased, and oxidized when positively biased. This could identify that PEDOT:PSS with indium ions from PEDOT:PSS etching ITO will lose dopants when negatively biased. The LRM shows that the device with indium ions has a stronger effect on the reduction property of PEDOT:PSS-PEG film than the device without indium ions. The contrast of the former device is 44%, that of the latter device is about 3%. The LRM also shows that the contrasts of the device based on PEDOT:PSS+PEG with LiCl, KCl, NaCl, InCl_3 are 30%, 27%, 15%, and 18%, respectively.展开更多
Multifunctional electrochromic-induced rechargeable aqueous batteries(MERABs) integrate electrochromism and aqueous ion batteries into one platform, which is able to deliver the conversion and storage of photo-thermal...Multifunctional electrochromic-induced rechargeable aqueous batteries(MERABs) integrate electrochromism and aqueous ion batteries into one platform, which is able to deliver the conversion and storage of photo-thermal-electrochemical sources.Aqueous ion batteries compensate for the drawbacks of slow kinetic reactions and unsatisfied storage capacities of electrochromic devices. On the other hand, electrochromic technology can enable dynamically regulation of solar light and heat radiation. However,MERABs still face several technical issues, including a trade-off between electrochromic and electrochemical performance, low conversion efficiency and poor service life. In this connection, novel device configuration and electrode materials, and an optimized compatibility need to be considered for multidisciplinary applications. In this review,the unique advantages, key challenges and advanced applications are elucidated in a timely and comprehensive manner. Firstly, the prerequisites for effective integration of the working mechanism and device configuration, as well as the choice of electrode materials are examined. Secondly, the latest advances in the applications of MERABs are discussed, including wearable, self-powered, integrated systems and multisystem conversion. Finally, perspectives on the current challenges and future development are outlined, highlighting the giant leap required from laboratory prototypes to large-scale production and eventual commercialization.展开更多
Exploring materials with high electrochemical activity is of keen interest for electrochemistry-controlled optical and energy storage devices.However,it remains a great challenge for transition metal oxides to meet th...Exploring materials with high electrochemical activity is of keen interest for electrochemistry-controlled optical and energy storage devices.However,it remains a great challenge for transition metal oxides to meet this feature due to their low electron conductivity and insufficient reaction sites.Here,we propose a type of transition metal phosphate(NiHPO_(4)·3H_(2)O,NHP)by a facile and scalable electrodeposition method,which can achieve the capability of efficient ion accommodation and injection/extraction for electrochromic energy storage applications.Specifically,the NHP film with an ultra-high transmittance(approach to 100%)achieves a large optical modulation(90.8%at 500 nm),high coloration efficiency(75.4 cm^(2)C^(-1)at 500 nm),and a high specific capacity of 47.8 mAh g^(-1)at 0.4 A g^(-1).Furthermore,the transformation mechanism of NHP upon electrochemical reaction is systematically elucidated using in situ and ex situ techniques.Ultimately,a large-area electrochromic smart window with 100 cm^(2)is constructed based on the NHP electrode,displaying superior electrochromic energy storage performance in regulating natural light and storing electrical charges.Our findings may open up new strategies for developing advanced electrochromic energy storage materials and smart windows.展开更多
Electrochromic and auto-bleaching processes at the WO2 anodic film in 0. 5 mol/L H2SO4 solution were investigated by cyclic voltammetry, a. c. impedance technique and photocurrent spectrometry. The colouration mechani...Electrochromic and auto-bleaching processes at the WO2 anodic film in 0. 5 mol/L H2SO4 solution were investigated by cyclic voltammetry, a. c. impedance technique and photocurrent spectrometry. The colouration mechanism consists of hydrogen adsorption on the WO2 surface and the transport of H atoms in the WO, lattice. The bleaching process involves at least two steps: transport of interstitial H atoms and hydrogen desorption on the W surface, resulting in interstitial H+ ions; then extration of the H+ ions driven by the external electric field. The auto-bleaching arises from the hydroxylation due to both partial interstitial H atoms and a little of water contained in the film.展开更多
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(...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 cm^(2)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.展开更多
Inorganic metal oxide electrochromic materials have good application prospects for energy-saving windows in buildings and smart display applications.Therefore,the development of electrochromic films with good cycling ...Inorganic metal oxide electrochromic materials have good application prospects for energy-saving windows in buildings and smart display applications.Therefore,the development of electrochromic films with good cycling stabilities,fast color-change response times,and high coloring efficiencies has attracted considerable attention.In this study,nanoflake Li-doped NiO electrochromic films were prepared using a hydrothermal method,and the films exhibited superior electrochromic performances in the LiOH electrolyte.Li^(+)ions doping increased the ion transmission rates of the NiO films,and effectively promoted the transportation of ions from the electrolyte into NiO films.Meanwhile,the nanoflake microstructure caused the NiO films to have larger specific surface areas,providing more active sites for electrochemical reactions.It was determined that the NiO-Li20%film exhibited an ultra-fast response in the LiOH electrolyte(coloring and bleaching times reached 3 and 1.5 s,respectively).Additionally,the coloration efficiency was 62.1 cm^(2)C^(−1),and good cycling stability was maintained beyond 1500 cycles.Finally,the simulation calculation results showed that Li doping weakened the adsorption strengths of the NiO films to OH^(−),which reduced the generation and decomposition of NiOOH and helped to improve the cycling stabilities of the films.Therefore,the research presented in this article provides a strategy for designing electrochromic materials in the future.展开更多
Electrochromic materials are capable of reversibly switching their colors or optical properties through redox reactions under applied voltages,which have shown great potential applications including smart windows,none...Electrochromic materials are capable of reversibly switching their colors or optical properties through redox reactions under applied voltages,which have shown great potential applications including smart windows,nonemissive displays,optical filters,among others.Although the current rigid electrochromic devices have shown emerging interest and developed rapidly,many applications(e.g.,wearable/deformable optoelectronics)are blocked due to their inflexible features.Herein,the adaption of rigid electrochromic devices to flexible ones is of particular interest for the new era of smart optoelectronics.In this review,the current state-of-the-art achievements of flexible electrochromic devices(FECDs)are highlighted,along with their design strategies and the choice of electrochromic materials.The recent research progress of FECDs is reviewed in detail,and the challenges and corresponding solutions for real-world applications of FECDs are discussed.Furthermore,we summarize the basic fabrication strategies of FECDs and their potential applications.In addition,the development trend,the perspectives,and the outlook of FECDs are discussed at the end of this Review,which may provide recommendations and potential directions to advance the practical applications of FECDs.展开更多
Vanadates are a class of the most promising electrochromic materials for displays as their multicolor characteristics.However,the slow switching times and vanadate dissolution issues of recently reported vanadates sig...Vanadates are a class of the most promising electrochromic materials for displays as their multicolor characteristics.However,the slow switching times and vanadate dissolution issues of recently reported vanadates significantly hinder their diverse practical applications.Herein,novel strategies are developed to design electrochemically stable vanadates having rapid switching times.We show that the interlayer spacing is greatly broadened by introducing sodium and lanthanum ions into V_(3)O_(8)interlayers,which facilitates the transportation of cations and enhances the electrochemical kinetics.In addition,a hybrid Zn^(2+)/Na^(+)electrolyte is designed to inhibit vanadate dissolution while significantly accelerating electrochemical kinetics.As a result,our electrochromic displays yield the most rapid switching times in comparison with any reported Zn-vanadate electrochromic displays.It is envisioned that stable vanadate-based electrochromic displays having video speed switching are appearing on the near horizon.展开更多
A four-element compact dual-band patch antenna having a common ground plane operating at 28/38 GHz is proposed formillimeter-wave communication systems in this paper.Themultiple-input-multiple-output(MIMO)antenna geom...A four-element compact dual-band patch antenna having a common ground plane operating at 28/38 GHz is proposed formillimeter-wave communication systems in this paper.Themultiple-input-multiple-output(MIMO)antenna geometry consists of a slotted ellipse enclosed within a hollow circle which is orthogonally rotated with a connected partial ground at the back.The overall size of the four elements MIMO antenna is 2.24λ×2.24λ(at 27.12GHz).The prototype of four-element MIMOresonator is designed and printed using Rogers RTDuroid 5880 withε_(r)=2.2 and loss tangent=0.0009 and having a thickness of 0.8 mm.It covers dual-band having a fractional bandwidth of 15.7%(27.12-31.34 GHz)and 4.2%(37.21-38.81 GHz)for millimeter-wave applications with a gain of more than 4 dBi at both bands.The proposed antenna analysis in terms ofMIMOdiversity parameters(Envelope Correlation Coefficient(ECC)and Diversity Gain(DG))is also carried out.The experimental result in terms of reflection coefficient,radiation pattern,gain and MIMOdiversity parameter correlates very well with the simulated ones that show the potential of the proposed design for MIMO applications at millimeter-wave frequencies.展开更多
基金supported by the National Natural Science Foundation of China(51902064)the Natural Science Foundation of Guangxi(2022GXNSFFA0350325)+2 种基金the Scientific and Technological Bases and Talents of Guangxi(Guike AD20159073)the special fund for“Guangxi Bagui Scholars”the“Guangxi HundredTalent Program”。
文摘Dual-band electrochromic smart windows(DESWs)with independent control of the transmittance of near-infrared and visible light show great potential in the application of smart and energy-saving buildings.The current strategy for building DESWs is to screen materials for composite or prepare plasmonic nanocrystal films.These rigorous preparation processes seriously limit the further development of DESWs.Herein,we report a facile and effective sol-gel strategy using a foaming agent to achieve porous Ti-doped tungsten oxide film for the high performance of DESWs.The introduction of foaming agent polyvinylpyrrolidone during the film preparation can increase the specific surface area and free carrier concentration of the films and enhance their independent regulation ability of near-infrared electrochromism.As a result,the optimal film shows excellent dual-band electrochromic properties,including high optical modulation(84.9%at 633 nm and 90.3%at 1200 nm),high coloration efficiency(114.9 cm^(2) C^(-1) at 633 nm and 420.3 cm^(2) C^(-1) at 1200 nm),quick switching time,excellent bistability,and good cycle stability(the transmittance modulation losses at 633 and 1200 nm were 11%and 3.5%respectively after 1000 cycles).A demonstrated DESW fabricated by the sol-gel film showed effective management of heat and light of sunlight.This study represents a significant advance in the preparation of dual-band electrochromic films,which will shed new light on advancing electrochromic technology for future energy-saving smart buildings.
基金financial support from the National Natural Science Foundation of China(22105106)the Natural Science Foundation of Jiangsu Province of China(BK20210603)+1 种基金the Nanjing Science and Technology Innovation Project for overseas Students(NJKCZYZZ2022–05)the Start-up Funding from NUPTSF(NY221003)。
文摘Electrochromic technology has gained significant attention in various fields such as displays,smart windows,biomedical monitoring,military camouflage,human-machine interaction,and electronic skin due to its ability to provide reversible and fast color changes under applied voltage.With the rapid development and increasing demand for flexible electronics,flexible electrochromic devices(FECDs)that offer smarter and more controllable light modulation hold great promise for practical applications.The electrochromic material(ECM)undergoing color changes during the electrochemical reactions is one of the key components in electrochromic devices.Among the ECMs,viologens,a family of organic small molecules with 1,1'-disubstituted-4,4'-dipyridinium salts,have garnered extensive research interest,due to their well-reversible redox reactions,excellent electron acceptance ability,and the ability to produce multiple colors.Notably,viologen-based FECDs demonstrate color changes in the liquid or semisolid electrolyte layer,eliminating the need for two solid electrodes and thus simplifying the device structure.Consequently,viologens offer significant potential for the development of FECDs with high optical contrast,fast response speed,and excellent stability.This review aims to provide a comprehensive overview of the progress and perspectives of viologen-based FECDs.It begins by summarizing the typical structure and recent exciting developments in viologen-based FECDs,along with their advantages and disadvantages.Furthermore,the review discusses recent advancements in FECDs with additional functionalities such as sensing,photochromism,and energy storage.Finally,the remaining challenges and potential research directions for the future of viologen-based FECDs are addressed.
基金Supported by the Natural Science Foundation of Tibet Autonomous Region(XZ202401ZR0025)the National Natural Science Founda-tion of China(62164011,62301081)the Natural Science Foundation of Shaanxi Province(2022JQ-589)。
文摘In this paper,a dual-band graphene-based frequency selective surface(GFSS)is investigated and the operating mechanism of this GFSS is analyzed.By adjusting the bias voltage to control the graphene chemical po-tential between 0 eV and 0.5 eV,the GFSS can achieve four working states:dual-band passband,high-pass lowimpedance,low-pass high-impedance,and band-stop.Based on this GFSS,a hexagonal radome on a broadband omnidirectional monopole antenna is proposed,which can achieve independent 360°six-beam omnidirectional scanning at 1.08 THz and 1.58 THz dual bands.In addition,while increasing the directionality,the peak gains of the dual bands reach 7.44 dBi and 6.67 dBi,respectively.This work provides a simple method for realizing multi-band terahertz multi-beam reconfigurable antennas.
基金supported by the National Research Foundation (NRF)grants funded by the Ministry of Education (2020R1A6A1A03038817),Republic of Korea。
文摘Functional materials may change color by heat and electricity separately or simultaneously in smart windows.These materials have not only demonstrated remarkable potential in the modulation of solar radiation but are also leading to the development of indoor environments that are more comfortable and conducive to improving individuals'quality of life.Unfortunately,dual-responsive materials have not received ample research attention due to economic and technological challenges.As a consequence,the broader utilization of smart windows faces hindrances.To address this new generational multistimulus responsive chromic materials,our group has adopted a developmental strategy to create a poly(NIPAM)n-HV as a switchable material by anchoring active viologen(HV)onto a phase-changing poly(NIPAM)n-based smart material for better utility and activity.These constructed smart windows facilitate individualistic reversible switching,from a highly transparent state to an opaque state(thermochromic)and a red state(electrochromic),as well as facilitate a simultaneous dual-stimuli response reversible switching from a clear transparent state to a fully opaque(thermochromic)and orange(electrochromic)states.Absolute privacy can be attained in smart windows designed for exclusive settings by achieving zero transmittance.Each unique chromic mode operates independently and modulates visible and near-infrared(NIR)light in a distinct manner.Hence,these smart windows with thermal and electric dual-stimuli responsiveness demonstrate remarkable heat regulation capabilities,rendering them highly attractive for applications in building facades,energy harvesting,privacy protection,and color display.
基金National Natural Science Foundation of China (Grant Nos. 22379077 and 22005163)。
文摘The electrochromic Li-ion batteries(ELIBs) combine the functions of electrochromism and energy storage,realizing the display of energy-storage levels by visual signals. However, the accompanying interfacial issues including physical contact and(electro)chemical stability should be taken into account when the conventional liquid/gel electrolytes are replaced with solid-state counterparts. Herein, the in-situ liquid-solid transitional succinonitrile(SCN) plastic glues are constructed between electrodes and poly(ethylene oxide)(PEO) polymer electrolytes, enabling an interface-reinforced solid-state ELIB.Specifically, the liquid SCN precursor can adequately wet electrode/PEO interfaces at high temperature,while it returns back to solid state at room temperature, leading to seamless interfacial contact and smooth ionic transfer without changing the solid state of the device. Moreover, the SCN interlayer suppresses the direct contact of PEO with electrodes containing high-valence metal ions, evoking the improved interfacial stability by inhibiting the oxidation of PEO. Therefore, the resultant solid-state ELIB with configuration of LiMn_(2)O_(4)/SCN-PEO-SCN/WO_(3) delivers an initial discharge capacity of 111 m A h g^(-1) along with a capacity retention of 88.3% after 200 cycles at 30 ℃. Meanwhile, the electrochromic function is integrated into the device by distinguishing its energy-storage levels through distinct color changes. This work proposes a promising solid-state ELIB with greatly reinforced interfacial compatibility by introducing in-situ solidified plastic glues.
基金supported by funding from Bavarian Center for Battery Technology(Bay Batt),Bayerisch-Tschechische Hochschulagentur(BTHA)(BTHA-AP-2022-45,BTHA-AP-2023-5,BTHA-AP2023-12,and BTHA-AP-2023-38)the University of BayreuthDeakin University Joint Ph.D.Program,Bayerische Forschungallianz(Bay FOR)(Bay Int An_UBT_2023_84)+2 种基金BK21 program from National Research Foundation of Korea,Erasmus+program from the European Union,Ministry of Education,Science and Technology as part of the Higher Education for Economic Transformation(HEET)Project(World Bank)Verband der Chemischen Industrie(Fonds der Chemischen Industrie,No.661740)collaboration project funding from Kangwon National University and LINC 3.0 Research Center,and the Deutsche Forschungsgemeinschaft(DFG,project number:533115776)。
文摘In recent times,future energy storage systems demand a multitude of functionalities beyond their traditional energy storage capabilities.In line with this technological shift,there is active research and development of electrochromic-energy storage systems designed to visualize electrochemical charging and discharging processes.The conventional electrochromic-energy storage devices primarily integrated supercapacitors,known for their high power density,to enable rapid color contrast.However,the low energy density of supercapacitors restricts overall energy storage capacity,acting as a significant barrier to expanding the application range of such systems.In this review,we introduce electrochromic zinc(Zn)-ion battery systems,which effectively overcome the limitation of low energy density,and provide illustrative examples of their applicability across diverse fields.Although many recent research works are present for electrochromic Zn-ion batteries,little review has so far taken place.Our objective is to discuss on the current progress and future directions for electrochromic Zn-ion batteries,which are applicable for wearable electronics applications and energy storage systems.This review provides an initial milestone for future researchers in electrochromic energy storage and zinc-ion batteries,which will lead to a stream of future works related to them.
基金supported by the Special Support Program for High-level Talents of Shaanxi Province(No.2020-44)Innnovative Talent Project of China and The Youth Innovation Team of Shaanxi Universities
文摘NiO,an anodic electrochromic material,has applications in energy-saving windows,intelligent displays,and military camouflage.However,its electrochromic mechanism and reasons for its performance degradation in alkaline aqueous electrolytes are complex and poorly understood,making it challenging to improve NiO thin films.We studied the phases and electrochemical characteristics of NiO films in different states(initial,colored,bleached and after 8000 cycles)and identified three main reasons for performance degradation.First,Ni(OH)_(2)is generated during electrochromic cycling and deposited on the NiO film surface,gradually yielding a NiO@Ni(OH)_(2)core-shell structure,isolating the internal NiO film from the electrolyte,and preventing ion transfer.Second,the core-shell structure causes the mode of electrical conduction to change from first-to second-order conduction,reducing the efficiency of ion transfer to the surface Ni(OH)_(2)layer.Third,Ni(OH)_(2)and NiOOH,which have similar crystal structures but different b-axis lattice parameters,are formed during electrochromic cycling,and large volume changes in the unit cell reduce the structural stability of the thin film.Finally,we clarified the mechanism of electrochromic performance degradation of NiO films in alkaline aqueous electrolytes and provide a route to activation of NiO films,which will promote the development of electrochromic technology.
基金supported by a grant of the Ministry of Research,Innovation and Digitization,CNCS–UEFISCDI,project number PNIII-P1-1.1-TE-2021-1110PNCDI III,contract number TE 83/2022,and project number PN-III-P2-2.1-PED-2019-3520PNCDI III,contract number 438PED/2020。
文摘The current investigation offers an innovative synthetic solution regarding electrochromic(EC)and energy storage applications by exploring phenoxazine(POZ)moiety.Subsequently,three POZ-based polymers(polyimide,polyazomethine,and polyamide)were synthesized to ascertain the superior performer.The polyamide exhibited remarkable attributes,including high redox stability during 500 repetitive CVs,optical contrast of 61.98%,rapid response times of 1.02 and 1.38 s for coloring and bleaching,EC efficiency of 280 cm^(2)C^(-1).and decays of the optical density and EC efficiency of only 12.18%and 6.23%after 1000 cycles.Then,the energy storage performance of polyamide PA was tested,for which the following parameters were obtained:74.7 F g^(-1)(CV,scan rate of 10 mV s^(-1))and 118 F g^(-1)(GCD,charging current of 0.1 A g^(-1)).Then,the polyamide was tested in EES devices,which yielded the following EC parameters:an optical contrast of 62.15%,response times of 9.24 and 5.01 s for coloring and bleaching,EC efficiency of 178 cm^(2)C^(-1),and moderate decays of 20.25%and 23.24%for the optical density and EC efficiency after 500 cycles.The energy storage performance included a capacitance of 106 F g^(-1)(CV,scan rate of 0.1 mV s^(-1))and 9.23 F g^(-1)(GCD,charging current of 0.1 A g^(-1)),capacitance decay of 11.9%after500 cycles,and 1.7 V retention after 2 h.Also,two EES devices connected in series powered a 3 V LED for almost 30 s.
基金supported by the NSFC(No.22002051)Jiangsu Provincial Double-Innovation Doctor Program(No.JSSCBS20210931)+4 种基金the Innovation/Entrepreneurship Program of Jiangsu Province(No.JSSCTD202146)China Postdoctoral Science Fund(No.2021M701484)Jiangsu Postdoctoral Fund(No.2021K251B)QD-NLED device structure optimization and electroluminescence mechanism research project(No.2022YFB3606503)Jiangsu Funding Program for Excellent Postdoctoral Talent.The authors are grateful for the technical support for Nano-X from Suzhou Institute of Nano-Tech and NanoBionics,Chinese Academy of Sciences(SINANO).
文摘Flexible electrochromic devices (FECDs) are promising candidates for the next generation of wearable electronics due to their low operating voltage and energy consumption. For the flexible electrochromic devices, the electrolyte is an important component. Typically, the electrolyte needs to be formulated according to the device structure and usage scenario. A high-performance electrolyte involves consideration of many factors, including choosing the right polymer, solvent, curing agent, and ion type to satisfy particular device specifications. In this work, a ultraviolet-curable solid–liquid host–guest (UV-SLHG) electrolyte is developed. Several aspects of performance are improved by introducing the solid–liquid coexisting microstructure without changing the electrolyte formulation, including excellent adhesion, a 30% increase in tensile characteristics, and a seven-fold increase in ionic conductivity when compared to a fully cured solid-state electrolyte. More importantly, the unique advantage of SLHG electrolytes lies that the thickness will not change significantly during bending. The FECD made by using the UV-SLHG-based electrolyte sustained 10,000 bending cycles at the bending radius of 2.5 mm while maintaining outstanding optical modulation. A wearable ring-type ECD and a battery-free FECD wine label were made as demonstrators. The UV-SLHG strategy is not only suitable for the FECDs but also universally applicable to other electrolyte-based of flexible electronics such as flexible capacitors and batteries.
基金funded by the Science and Technology Development Fund,Macao SAR(File no.0052/2021/AGJ,0027/2023/AMJ,0083/2023/ITP2 and 0107/2023/AFJ)the Multi-Year Research Grants(MYRG2022-00063-IAPME,MYRG-GRG2023-00230-IAPME-UMDF)from the University of Macao+1 种基金the Guangdong Science and Technology Plan(2022A0505020022)the Major Science and Technology Research and Development Project of Jiangxi Province(20223AAE01003)。
文摘Aqueous electrochromic battery(ECB)has shown intense potential for achieving energy storage and saving simultaneously.While tungsten oxide(WO_(3))is the most promising EC material for commercialization,the cycling stability of WO_(3)-based aqueous ECBs is currently unsatisfactory due to the repeated phase transition during the redox process and the corrosion by acidic electrolytes.Herein,we present a titanium-tungsten oxide alloy(Ti-WO_(3))with controllable morphology and crystal phase synthesized by a facile hot injection method to overcome the challenges.In contrast to conventional monoclinic WO_(3),the Ti-WO_(3)nanorods can stably maintain their cubic crystal phase during the redox reaction in an acidic electrolyte,thus leading to dramatically enhanced response speed and cycling stability,Specifically,when working in a well-matched hybrid Al^(3+)/Zn^(2+)aqueous electrolyte,our phasetransition-free cubic Ti-WO_(3)exhibits an ultra-high cycling stability(>20000 cycles),fast response speed(3,95 s/4,65 s for bleaching/coloring),as well as excellent discharge areal capacity of 214.5 mA h m^(-2),We further fabricate a fully complementa ry aqueous electrochromic device,for the first time,using a Ti-WO_(3)/Prussian blue device architecture.Remarkably,the complementary ECB shows>10000 stable operation cycles,attesting to the feasibility of our Ti-WO_(3)for practical applications.Our work validates the significance of inhibiting the phase transitions of WO_(3)during the electrochromic process for realizing highly cyclable aqueous ECB,which can possibly provide a generalized design guidance for other high-quality metallic oxides for electrochemical applications.
基金Project supported by the National High Technology Research and Development Program of China(Grant No.2015AA034201)the Chinese Universities Scientific Fund(Grant No.2015LX002)
文摘Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)(PEDOT:PSS) is usually sandwiched between indium tin oxide(ITO) and a functional polymer in order to improve the performance of the device. However, because of the strong acidic nature of PEDOT:PSS, the instability of the ITO/PEDOT:PSS interface is also observed. The mechanism of degradation of the device remains is unclear and needs to be further studied. In this article, we investigate the in-situ electrochromism of PEDOT:PSS to disclose the cause of the degradation. X-ray photoelectron spectroscopy(XPS) was used to characterize the PEDOT:PSS films, as well as the PEDOT:PSS plus polyethylene glycol(PEG) films with and without indium ions. The electrochromic devices(ECD) based on PEDOT:PSS and PEG with and without indium ions are carried out by in-situ micro-Raman and laser reflective measurement(LRM). For comparison, ECD based on PEDOT:PSS and PEG films with LiCl, KCl, NaCl or InCl_3 are also investigated by LRM. The results show that PEDOT:PSS is further reduced when negatively biased, and oxidized when positively biased. This could identify that PEDOT:PSS with indium ions from PEDOT:PSS etching ITO will lose dopants when negatively biased. The LRM shows that the device with indium ions has a stronger effect on the reduction property of PEDOT:PSS-PEG film than the device without indium ions. The contrast of the former device is 44%, that of the latter device is about 3%. The LRM also shows that the contrasts of the device based on PEDOT:PSS+PEG with LiCl, KCl, NaCl, InCl_3 are 30%, 27%, 15%, and 18%, respectively.
基金support by Shanghai Municipal Education Commission (No. 2019-01-07-00-09E00020), for research conducted at the Shanghai Universitysupport by Independent depolyment project of Qinghai Institute of Salt Lakes, Chinese Academy of Sciences (E260GC0401)support by the Singapore National Research Foundation (NRF-CRP26-2021-0003, NRF), for research conducted at the National University of Singapore。
文摘Multifunctional electrochromic-induced rechargeable aqueous batteries(MERABs) integrate electrochromism and aqueous ion batteries into one platform, which is able to deliver the conversion and storage of photo-thermal-electrochemical sources.Aqueous ion batteries compensate for the drawbacks of slow kinetic reactions and unsatisfied storage capacities of electrochromic devices. On the other hand, electrochromic technology can enable dynamically regulation of solar light and heat radiation. However,MERABs still face several technical issues, including a trade-off between electrochromic and electrochemical performance, low conversion efficiency and poor service life. In this connection, novel device configuration and electrode materials, and an optimized compatibility need to be considered for multidisciplinary applications. In this review,the unique advantages, key challenges and advanced applications are elucidated in a timely and comprehensive manner. Firstly, the prerequisites for effective integration of the working mechanism and device configuration, as well as the choice of electrode materials are examined. Secondly, the latest advances in the applications of MERABs are discussed, including wearable, self-powered, integrated systems and multisystem conversion. Finally, perspectives on the current challenges and future development are outlined, highlighting the giant leap required from laboratory prototypes to large-scale production and eventual commercialization.
基金financially the National Natural Science Foundation of China(U2004175,51902086 and 62222402)China Postdoctoral Science Foundation(2022M711036)the Key Scientific Research Project plan of the University in Henan Province(22A430002)。
文摘Exploring materials with high electrochemical activity is of keen interest for electrochemistry-controlled optical and energy storage devices.However,it remains a great challenge for transition metal oxides to meet this feature due to their low electron conductivity and insufficient reaction sites.Here,we propose a type of transition metal phosphate(NiHPO_(4)·3H_(2)O,NHP)by a facile and scalable electrodeposition method,which can achieve the capability of efficient ion accommodation and injection/extraction for electrochromic energy storage applications.Specifically,the NHP film with an ultra-high transmittance(approach to 100%)achieves a large optical modulation(90.8%at 500 nm),high coloration efficiency(75.4 cm^(2)C^(-1)at 500 nm),and a high specific capacity of 47.8 mAh g^(-1)at 0.4 A g^(-1).Furthermore,the transformation mechanism of NHP upon electrochemical reaction is systematically elucidated using in situ and ex situ techniques.Ultimately,a large-area electrochromic smart window with 100 cm^(2)is constructed based on the NHP electrode,displaying superior electrochromic energy storage performance in regulating natural light and storing electrical charges.Our findings may open up new strategies for developing advanced electrochromic energy storage materials and smart windows.
基金The project Supported by National Natural Science Foundation of China.
文摘Electrochromic and auto-bleaching processes at the WO2 anodic film in 0. 5 mol/L H2SO4 solution were investigated by cyclic voltammetry, a. c. impedance technique and photocurrent spectrometry. The colouration mechanism consists of hydrogen adsorption on the WO2 surface and the transport of H atoms in the WO, lattice. The bleaching process involves at least two steps: transport of interstitial H atoms and hydrogen desorption on the W surface, resulting in interstitial H+ ions; then extration of the H+ ions driven by the external electric field. The auto-bleaching arises from the hydroxylation due to both partial interstitial H atoms and a little of water contained in the film.
基金supports from the National Natural Science Foundation of China (Grant No. 52175300)Fundamental Research Funds for the Central Universities (2022FRFK060008)+2 种基金Heilongjiang Touyan Innovation Team Program (HITTY-20190013)Shenzhen Fundamental Research Programs (JCYJ20200925160843002)Start-up fund of SUSTech (Y01256114)
文摘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 cm^(2)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.
基金supported by the Key Science and Technology Innovation Team of Shaanxi Province(No.2014KCT-03)Special Support Program for High-level Talents of Shaanxi Province(No.2020-44)China Postdoctoral Science Foundation(No.2019M663990).
文摘Inorganic metal oxide electrochromic materials have good application prospects for energy-saving windows in buildings and smart display applications.Therefore,the development of electrochromic films with good cycling stabilities,fast color-change response times,and high coloring efficiencies has attracted considerable attention.In this study,nanoflake Li-doped NiO electrochromic films were prepared using a hydrothermal method,and the films exhibited superior electrochromic performances in the LiOH electrolyte.Li^(+)ions doping increased the ion transmission rates of the NiO films,and effectively promoted the transportation of ions from the electrolyte into NiO films.Meanwhile,the nanoflake microstructure caused the NiO films to have larger specific surface areas,providing more active sites for electrochemical reactions.It was determined that the NiO-Li20%film exhibited an ultra-fast response in the LiOH electrolyte(coloring and bleaching times reached 3 and 1.5 s,respectively).Additionally,the coloration efficiency was 62.1 cm^(2)C^(−1),and good cycling stability was maintained beyond 1500 cycles.Finally,the simulation calculation results showed that Li doping weakened the adsorption strengths of the NiO films to OH^(−),which reduced the generation and decomposition of NiOOH and helped to improve the cycling stabilities of the films.Therefore,the research presented in this article provides a strategy for designing electrochromic materials in the future.
基金the support from the “Qilu Young Scholar” program (62460082163097) of Shandong Universitythe National Natural Science Foundation of China (62105185)+1 种基金Shandong Excellent Young Scientists Fund Program (Overseas) (2022HWYQ-021)Guangdong Basic and Applied Basic Research Foundation (2022A1515011516)
文摘Electrochromic materials are capable of reversibly switching their colors or optical properties through redox reactions under applied voltages,which have shown great potential applications including smart windows,nonemissive displays,optical filters,among others.Although the current rigid electrochromic devices have shown emerging interest and developed rapidly,many applications(e.g.,wearable/deformable optoelectronics)are blocked due to their inflexible features.Herein,the adaption of rigid electrochromic devices to flexible ones is of particular interest for the new era of smart optoelectronics.In this review,the current state-of-the-art achievements of flexible electrochromic devices(FECDs)are highlighted,along with their design strategies and the choice of electrochromic materials.The recent research progress of FECDs is reviewed in detail,and the challenges and corresponding solutions for real-world applications of FECDs are discussed.Furthermore,we summarize the basic fabrication strategies of FECDs and their potential applications.In addition,the development trend,the perspectives,and the outlook of FECDs are discussed at the end of this Review,which may provide recommendations and potential directions to advance the practical applications of FECDs.
基金The authors acknowledge the support from the National Natural Science Foundation of China(62105185,62375157,52002196)Natural Science Foundation of Guangdong Province(2022A1515011516)+2 种基金Natural Science Foundation of Shandong Province(ZR2020QF084)Shandong Excellent Young Scientists Fund Program(Overseas,2022HWYQ-021)the Open Foundation of the State Key Laboratory of Featured Metal Materials and Life-Cycle Safety for Composite Structures,Guangxi University(2022GXYSOF06).
文摘Vanadates are a class of the most promising electrochromic materials for displays as their multicolor characteristics.However,the slow switching times and vanadate dissolution issues of recently reported vanadates significantly hinder their diverse practical applications.Herein,novel strategies are developed to design electrochemically stable vanadates having rapid switching times.We show that the interlayer spacing is greatly broadened by introducing sodium and lanthanum ions into V_(3)O_(8)interlayers,which facilitates the transportation of cations and enhances the electrochemical kinetics.In addition,a hybrid Zn^(2+)/Na^(+)electrolyte is designed to inhibit vanadate dissolution while significantly accelerating electrochemical kinetics.As a result,our electrochromic displays yield the most rapid switching times in comparison with any reported Zn-vanadate electrochromic displays.It is envisioned that stable vanadate-based electrochromic displays having video speed switching are appearing on the near horizon.
基金This work is supported by the Moore4Medical Project,funded within ECSEL JU in collaboration with the EU H2020 Framework Programme(H2020/2014-2020)under Grant Agreement H2020-ECSEL-2019-IA-876190Fundacao para a Ciência eTecnologia(ECSEL/0006/2019)This work is also funded by the FCT/MEC through national funds and when applicable co-financed by the ERDF,under the PT2020 Partnership Agreement under the UID/EEA/50008/2020 Project.
文摘A four-element compact dual-band patch antenna having a common ground plane operating at 28/38 GHz is proposed formillimeter-wave communication systems in this paper.Themultiple-input-multiple-output(MIMO)antenna geometry consists of a slotted ellipse enclosed within a hollow circle which is orthogonally rotated with a connected partial ground at the back.The overall size of the four elements MIMO antenna is 2.24λ×2.24λ(at 27.12GHz).The prototype of four-element MIMOresonator is designed and printed using Rogers RTDuroid 5880 withε_(r)=2.2 and loss tangent=0.0009 and having a thickness of 0.8 mm.It covers dual-band having a fractional bandwidth of 15.7%(27.12-31.34 GHz)and 4.2%(37.21-38.81 GHz)for millimeter-wave applications with a gain of more than 4 dBi at both bands.The proposed antenna analysis in terms ofMIMOdiversity parameters(Envelope Correlation Coefficient(ECC)and Diversity Gain(DG))is also carried out.The experimental result in terms of reflection coefficient,radiation pattern,gain and MIMOdiversity parameter correlates very well with the simulated ones that show the potential of the proposed design for MIMO applications at millimeter-wave frequencies.