Two viologen derivatives containing fluorine substituent(F)with an asymmetric structures,1,1'-bis(4-(trifluoromethyl)phenyl)-[4,4'-bipyridine]dihexafluorophosphate(DFPV)and 1-benzyl-1'-(4-(trifluoromethyl)...Two viologen derivatives containing fluorine substituent(F)with an asymmetric structures,1,1'-bis(4-(trifluoromethyl)phenyl)-[4,4'-bipyridine]dihexafluorophosphate(DFPV)and 1-benzyl-1'-(4-(trifluoromethyl)phenyl)-[4,4'-bipyridine]di-hexafluorophosphate(Bn-FPV),were synthesized.These viologen derivatives as active materials were used to assemble both flexible and rigid electrochromic devices(ECDs).ECDs based on DFPV exhibited reversible color change from colorless to deep green and ECDs based on Bn-FPV exhibited reversible color change from colorless to blue-green within applied voltage.It was found that the devices based on DFPV showed cycle stability,which could still maintain more than 90% after 1000 cycles.In addition,the modulation rate of the device to the solar irradiance is also calculated to characterize its application potential in smart windows.Among them,the rigid device(R-DFPV)based on the DFPV has a large solar irradiance modulation rate of 54.66%,which has the potential to be used as smart windows.展开更多
Dual-band electrochromic devices capable of the spectral-selective modulation of visible(VIS)light and near-infrared(NIR)can notably reduce the energy consumption of buildings and improve the occupants’visual and the...Dual-band electrochromic devices capable of the spectral-selective modulation of visible(VIS)light and near-infrared(NIR)can notably reduce the energy consumption of buildings and improve the occupants’visual and thermal comfort.However,the low optical modulation and poor durability of these devices severely limit its practical applications.Herein,we demonstrate an efficient and flexible bifunctional dual-band electrochromic device which not only shows excellent spectral-selective electrochromic performance with a high optical modulation and a long cycle life,but also displays a high capacitance and a high energy recycling efficiency of 51.4%,integrating energy-saving with energy-storage.The nanowires structure and abundant oxygen-vacancies of oxygen-deficient tungsten oxide nanowires endows it high flexibility and a high optical modulation of 73.1%and 85.3%at 633 and 1200 nm respectively.The prototype device assembled can modulate the VIS light and NIR independently and effectively through three distinct modes with a long cycle life(3.3%capacity loss after 10,000 cycles)and a high energy-saving performance(8.8℃lower than the common glass).Furthermore,simulations also demonstrate that our device outperforms the commercial low-emissivity glass in terms of energy-saving in most climatic zones around the world.Such windows represent an intriguing potential technology to improve the building energy efficiency.展开更多
Electrochromic(EC)smart windows utilizing a reversible metal electrodeposition device(RMED)offer a compelling alternative for dynamically regulating transmissions of optical and thermal energy.An EC device(ECD)is cons...Electrochromic(EC)smart windows utilizing a reversible metal electrodeposition device(RMED)offer a compelling alternative for dynamically regulating transmissions of optical and thermal energy.An EC device(ECD)is constructed by reversible metal electrodeposition(RME)of Bi/Cu on WO_(3)·xH_(2)O film electrodeposited onto fluorine-doped tin oxide(FTO)transparent conductive glass.The electrolyte consists of CuCl_(2),BiCl_(3),KCl and HCl aqueous solution,supplying necessary components for both electrochemical and electrodeposition processes.The ECD shows ability to rapidly transition between colorless and black states,which achieves a large optical modulation of 77.0%at 570 nm.In the black state,the ECD exhibits a near-zero transmittance in the wavelength range of 400-1100 nm while maintaining 96.6%of its initial optical modulation after coloration/bleaching cycling of 60000 s,exhibiting good cyclic stability.This RMED has relatively high stability under open-circuit voltage and also possesses excellent heat insulation performance.The results offer a solution to overcome the poor cyclic stability of RMEDs and improve the optical modulation of ECDs.展开更多
Sodium-ion-based electrochromic device(SECD)has been identified as an appealing cost-effective alternative of lithium-based counterparts,only if it can address the challenges in association with the inadequate electro...Sodium-ion-based electrochromic device(SECD)has been identified as an appealing cost-effective alternative of lithium-based counterparts,only if it can address the challenges in association with the inadequate electrochromic performance.In this regard,the quantized strategy is a particularly promising approach owing to the large surface-to-volume ratio and high reaction activity.However,quantum dots inevitably suffer from volume changes and undesired aggregation during electrochemical cycling.Herein,bioinspired from the robust connection of alveoli in lung,we propose a stable electrode,where WO_(3) quantum dots(WQDs)are robustly anchored on Ti_(3)C_(2) MXene through the strong chemical bonds of W-O-Ti.Theoretical results reveal the fundamental mechanism of the volume changes within WQDs and the dynamic diffusion process of sodium ions.The WQD@MXene electrodes exhibit a nearly twofold enhancement in cycling performance(1000 vs 500 cycles),coloration speed(3.2 vs 6.0 s),and areal capacity(87.5 vs 43.9 mAhm^(-2) at 0.1 mA cm^(-2)),compared to those of the pristine WQD electrode.As a proof-of-concept demonstration,a smart house system integrated with SECDs demonstrates a“3-in-1”device,enabling a combination of energy-saving,energy storage,and display functionalities.The present work significantly advances the versatile applications of cost-effective electrochromic electronics in interdisciplinary.展开更多
Wearable flexible sensor devices have the characteristics of lightweight and miniaturization.Currently,power supply and detection components limit the portability of wearable flexible sensor devices.Meanwhile,conventi...Wearable flexible sensor devices have the characteristics of lightweight and miniaturization.Currently,power supply and detection components limit the portability of wearable flexible sensor devices.Meanwhile,conventional liquid electrolytes are unsuitable for the integration of sensing devices.To address these constraints,wearable biofuel cells and flexible electrochromic displays have been introduced,which can improve integration with other devices,safety,and color-coded display data.Meanwhile,electrode chips prepared through screen printing technology can further improve portability.In this work,a wearable sensor device with screen-printed chips was constructed and used for non-invasive detection of glucose.Agarose gel electrolytes doped with PDA-CNTs were prepared,and the mechanical strength and moisture retention were significantly improved compared with traditional gel electrolytes.Glucose in interstitial fluid was non-invasive extracted to the skin surface using reverse iontophoresis.As a biofuel for wearable biofuel cells,glucose drives self-powered sensor and electrochromic display to produce color change,allowing for visually measurement of glucose levels in body fluids.Accurate detection results can be visualized by reading the RGB value with a cell phone.展开更多
Traditional electrodes for flexible/wearable electrochromic zinc ion batteries(EC-ZIBs)are typically prepared using electrodeposition or hydrothermal methods which suffer from poor adhesion,leading to significan perfo...Traditional electrodes for flexible/wearable electrochromic zinc ion batteries(EC-ZIBs)are typically prepared using electrodeposition or hydrothermal methods which suffer from poor adhesion,leading to significan performance degradation during repeated bending.In this paper,a Prussian blue electrode with MXene(MPB elec trode)-assisted in situ growth was prepared by the two-dimensional-material-assisted in situ growth(TAIG)method.The MPB electrode,achieved through simple immersion,features a nanoparticle shape with strong bonding to the flexible substrate.This nanoparticle-shaped PB does not clog the pores of the nylon fibers and grows inside the nylon fibers,which ultimately shortens the ion channels,allowing short ion diffusion pathways,fas electrochemical kinetics,favorable electrolyte penetration and improved specific capacity.In the fabrication of EC-ZIB devices,the MPB cathode exhibits a high specific capacity of 197.2 mAh g^(-1)at 2 A g^(-1)and retains 79.7%of its capacity even with a tenfold increase in current density.Additionally,the MPB electrode demonstrates excellent electrochromic performance(yellow,green and blue)within the range of 0.5 to 1.8 V,with rapid switching time of only 2.2 s for coloring and 2.0 s for bleaching.Therefore,the MPB electrodes fulfill the requirements for multifunctional devices,allowing easy monitoring of energy storage levels through color changes,and showing potential applications in smart camouflage,wearable displays and other fields,promoting the development of flexible smart energy storage devices.展开更多
Flexible electrochromic devices(FECDs)demonstrate significant potential for applications in wearable elec-tronics,military camouflage,and flexible smart displays.As a crucial electrochromic material,poly(3,4-ethylened...Flexible electrochromic devices(FECDs)demonstrate significant potential for applications in wearable elec-tronics,military camouflage,and flexible smart displays.As a crucial electrochromic material,poly(3,4-ethylenedioxythiophene):polystyrene sulfonate(PEDOT:PSS)is widely used in FECDs due to its excellent mechanical flexibility,tunable conductivity,and non-toxicity.However,the manufacturing process for patterned PEDOT:PSS electrochromic devices remains intricate,costly,and challenging to personalize.To address this challenge,we have developed a 3D-printable ink with controllable rheological properties through a concentration-tuning strategy,enabling programmable,patterned printing of PEDOT-based conductive polymer electrochromic layers.The 3D-printed FECDs exhibit outstanding electrochromic performance,including a high optical contrast(up to 47.9%at 635 nm),fast response times(t_(c)=1.6 s;t_(b)=0.6 s),high coloration efficiency(352 cm^(2) C^(-1)),and good cycling stability(with only a 9.3%decrease in optical contrast after 100 electrochemical cycles).Finally,we utilize 3D printing technology to construct flexible,patterned PEDOT:PSS electrochromic devices with bespoke butterfly designs.This work establishes the theoretical foundation for the application of 3D printing technology in PEDOT:PSS flexible electrochromic devices.展开更多
Vanadium oxide(VO_(X))with tunable interlayer spacing and variable valence states of vanadium ions offers tremendous opportunities in aqueous electrochromic devices but is still challenging.Herein,a poly aniline(PANI)...Vanadium oxide(VO_(X))with tunable interlayer spacing and variable valence states of vanadium ions offers tremendous opportunities in aqueous electrochromic devices but is still challenging.Herein,a poly aniline(PANI)-VO_(X)composite material has been designed,increasing the conductivity and the structure stability.Owning to these virtues,the PANI-VO_(X)composite material achieves a high capacitance of 332 mAh·g^(-1)at 0.1 A·g^(-1)and a superior cycling performance(72%ΔT retention after 500 cycles).Importantly,in-situ Raman spectroscopy has been utilized to reveal the rapid formation of Zn_(3)(OH)_(2)V_(2)O_(7)·nH_(2)O and the reversible change of PANI-VO_(X),which can further assist the development of aqueous electrochromic devices.This work highlights the understanding of the Zn^(2+)electrochromic mechanism and sheds some light on organic-inorganic composite electrochromic materials.展开更多
This paper adopted the hydrothermal method to prepare tungsten oxide(WO_(3))nanorod films and studied the effects of precursor solution concentration(0.02,0.03,0.06 mol/L peroxytungstic acid)and annealing temperature(...This paper adopted the hydrothermal method to prepare tungsten oxide(WO_(3))nanorod films and studied the effects of precursor solution concentration(0.02,0.03,0.06 mol/L peroxytungstic acid)and annealing temperature(200,300,400℃)on their electrochromic properties.The microstructure characterization of WO_(3) films were performed using scanning electron microscope(SEM),X-ray diffraction(XRD),and transmission electron microscope(TEM),and their electrochromic properties were tested by combining an electrochemical workstation with an ultraviolet-visible spectrophotometer.The results showed that the precursor solution concentration directly affected the thickness(290,560,990 nm)and microstructure of WO_(3) films,significantly impacting their electrochromic properties.However,the annealing temperature had a negligible effect.As the precursor solution concentration increased,the optical modulation of WO_(3) films gradually decreased,reaching 51.1%,43.8%,and 35.1%,respectively.The switching time first increased and then stabilized,with coloring times of 7.3,7.7,and 7.7 s,respectively,and bleaching times of 3.8,6.5,and 6.5 s,respectively.The coloration efficiency gradually increased but the increase was relatively small,reaching 41.8,44.4,and 44.8 cm^(2)/C,respectively.Moreover,the cycling stability of WO_(3) films was poor,with the ratios of the final value of optical modulation to the initial value 0.33,0.26,and 0.34,respectively.Additionally,there were bigger differences in the bleached state transmittance,while the colored state transmittance showed smaller variations.However,the former has better cycling stability than the latter.In summary,to obtain better electrochromic properties,the thickness of WO_(3) films should not exceed 290 nm.展开更多
Electrochromism is the process by which a material applies a small electrical signal to change the optical properties(transmittance,reflectance,absorptivity and emissivity)of the material reversibly or permanently thr...Electrochromism is the process by which a material applies a small electrical signal to change the optical properties(transmittance,reflectance,absorptivity and emissivity)of the material reversibly or permanently through REDOX reactions resulting from ion and electron embedding/ejection.Metal-organic framework(MOF)are advantageous materials for electrochromic application due to their high porosity,large specific surface area and orderly pore structure,that promotes the adsorption of electrolyte ions,ion diffusion and charge transfer.In addition,MOFs possess a variety of ligands and metal centers,allowing for design of composition types and pore structure sizes.This grants them the advantages of both organic electrochromic materials,such as vivid colors and fast color transformation,and inorganic electrochromic materials,like high coloring efficiency and excellent stability.This paper reviews the current research progress of MOF electrochromic materials,including materials design,electrochromic properties,and application.展开更多
Zinc-anode-based electrochromic devices(ZECDs) are emerging as the next-generation energy-e cient transparent electronics. We report anatase W-doped TiO_(2) nanocrystals(NCs) as a Zn^(2+) active electrochromic materia...Zinc-anode-based electrochromic devices(ZECDs) are emerging as the next-generation energy-e cient transparent electronics. We report anatase W-doped TiO_(2) nanocrystals(NCs) as a Zn^(2+) active electrochromic material. It demonstrates that the W doping in TiO_(2) highly reduces the Zn^(2+) intercalation energy,thus triggering the electrochromism. The prototype ZECDs based on W-doped TiO_(2) NCs deliver a high optical modulation(66% at 550 nm),fast spectral response times(9/2.7 s at 550 nm for coloration/bleaching),and good electrochemical stability(8.2% optical modulation loss after 1000 cycles).展开更多
The high quality TiO2, MoO3-doped WO3 electrochromic film was prepared by the sol-gel method for the first time.The sol, which has hydrogen peroxide （H2O2） and oxalic acid （H2C2O4）, was very stable at room tempera...The high quality TiO2, MoO3-doped WO3 electrochromic film was prepared by the sol-gel method for the first time.The sol, which has hydrogen peroxide （H2O2） and oxalic acid （H2C2O4）, was very stable at room temperature and quite suitable for the deposition of films. The WO3 electrochromic film prepared from this doped sol had excellent performance, such as short response time, no cracks, good adhesion to the substrate, high coloring efficiency and longevity of service.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
Abstract： A new compound 1-ethyl-1＇-（4-vinylbenzyl）-4, 4＇-bipyridinium chloride and iodide has been synthesized. The cyclic voltammogram and impedance spectra indicated that a layer of viologen＇s electrochromic ...Abstract： A new compound 1-ethyl-1＇-（4-vinylbenzyl）-4, 4＇-bipyridinium chloride and iodide has been synthesized. The cyclic voltammogram and impedance spectra indicated that a layer of viologen＇s electrochromic （EC） film could be deposited on conductive ITO glass working electrode With polyelectrolyte as ionic conduction layer, solid EC devices based on this compound have been assembled and their thickness was about 2.35 mm. When different voltages were added, they showed blue or violet red color. After optimization, its response time was less than 50 ms, the number of redox circulation was over 107 and the color of coloration states could be kept for 3 days. This kind of EC device can meet the demand of electronic ink.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
Electrochromic technology plays a significant role in energy conservation,while its performance is greatly limited by the transport behavior of ions and electrons.Hence,an electrochromic system with overall excellent ...Electrochromic technology plays a significant role in energy conservation,while its performance is greatly limited by the transport behavior of ions and electrons.Hence,an electrochromic system with overall excellent performances still need to be explored.Initially motivated by the high ionic and electronic conductivity of transition metal carbide or nitride(MXene),we design a feasible procedure to synthesize the MXene/WO3−x composite electrochromic film.The consequently boosted electrochromic performances prove that the addition of MXene is an effective strategy for simultaneously enhancing electrons and ions transport behavior in electrochromic layer.The MXene/WO3−x electrochromic device exhibits enhanced transmittance modulation and coloration efficiency(60.4%,69.1 cm^2 C^−1),higher diffusion coefficient of Li+and excellent cycling stability(200 cycles)over the pure WO3−x device.Meanwhile,numerical stimulation theoretically explores the mechanism and kinetics of the lithium ion diffusion,and proves the spatial and time distributions of higher Li+concentration in MXene/WO3−x composite electrochromic layer.Both experiments and theoretical data reveal that the addition of MXene is effective to promote the transport kinetics of ions and electrons simultaneously and thus realizing a high-performance electrochromic device.This work opens new avenues for electrochromic materials design and deepens the study of kinetics mechanism of ion diffusion in electrochromic devices.展开更多
In this study,novel electrochromic copolymers of 3,4-ethylenedioxythiophene(EDOT)and(E)-1,2-bis(2-fluoro-4-(4-hexylthiophen-2-yl)phenyl)diazene(M1)with different monomer feed ratios were designed and synthesized elect...In this study,novel electrochromic copolymers of 3,4-ethylenedioxythiophene(EDOT)and(E)-1,2-bis(2-fluoro-4-(4-hexylthiophen-2-yl)phenyl)diazene(M1)with different monomer feed ratios were designed and synthesized electrochemically.Electrochemical and spectroelectrochemical characterizations were performed using voltammetry and UV-Vis-NIR spectrophotometry techniques to test the applicability of copolymers for electrochromic applications.In terms of electrochemical behaviors,addition of an electron-rich EDOT unit into the azobenzenecontaining copolymer increased the electron density on the polymer chain and afforded copolymers with very low oxidation potentials at around0.30 V.While the homopolymers(P1 and PEDOT)exhibited neutral state absorptions centered at 510 and 583 nm,EDOT-bearing copolymers showed red shifted absorptions compared to those of P1 with narrower optical band gaps.In addition,the poor optical contrast and switching times of azobenzene-bearing homopolymer were significantly improved with EDOT addition into the copolymer chain.As a result of the promising electrochromic and kinetic preperties,Co P1.5-bearing single layer electrochromic device that works between purple and light greenish blue colors was constructed and characterized.展开更多
Five novel near-infrared electrochromic aromatic polyimides （PIs） with pendent benzimidazole group were synthesized from 4,4＇-diamino-4＂-（1-benzylbenzimidazol-2-yl）triphenylamine （named as DBBT） with five diff...Five novel near-infrared electrochromic aromatic polyimides （PIs） with pendent benzimidazole group were synthesized from 4,4＇-diamino-4＂-（1-benzylbenzimidazol-2-yl）triphenylamine （named as DBBT） with five different dianhydrides via two-step polymerization process, respectively. The maximum UV-Vis absorption bands of these PIs locate at about 335 nm for solid films due to the π-π＊ transitions. A reversible pair of distinct redox peaks, that were associated with a noticeable color change from original yellow to blue, was observed in the cyclic voltammetry （CV） test. A new absorption peak emerged at 847 nm in near-infrared （NIR） region with increasing voltage in UV-Vis-NIR spectrum, which indicates that PI can be used as NIR electrochromic material. These novel PIs have good electrochemical stability, appropriate energy levels for the highest occupied molecular orbital （HOMO） and the lowest unoccupied molecular orbital （LUMO）, in the range of-5.17 eV to -5.20 eV and -2.14 eV to -2.26 eV （versus the vacuum level） determined by cyclic voltammetry method. These values basically consisted with the results of quantum chemical calculation. These polyimides can be used as novel electrochromic and hole transportation materials.展开更多
This research concerns the development of lithium ions conductive electrolyte from poly(vinyl butyral)(PVB)resin for use as a special interlayer film in electrochromic glass.To obtain the final PVB film with high ioni...This research concerns the development of lithium ions conductive electrolyte from poly(vinyl butyral)(PVB)resin for use as a special interlayer film in electrochromic glass.To obtain the final PVB film with high ionic conductivity and thermal stability,a masterbatch was firstly prepared by mixing of PVB resin with lithium salt(LiClO_(4))and additives in an aqueous ethanol solution.After this,the dried masterbatch were converted into final films by an extrusion process.In this study,PVB film with the highest ionic conductivity value of 4.85×10^(-6) was obtained when the masterbatch was diluted with the neat PVB resin at the weight ratio of 2:1 in the extruder prior to fabrication.The results from cyclic voltammetry over 100 cycles,showed that performance of the electrochromic device(ITO/WO_(3)/PVB electrolyte/ITO)fabricated by using the above PVB film is stable and reversible.In overall,this work demonstrates that ion conductive PVB films with compromised ionic conductivity and thermal stability can be prepared via an extrusion process without the need to modify chemical structure of PVB.This was carried out through the masterbatch approach,by introducing (LiClO_(4)) salts into the plasticized PVB via a solution mixing process prior to converting it into a final film via the extrusion process.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
基金Funded by the Natural Science Foundation of Guangdong(Nos.2014A030313241,2014B090901068,and 2016A010103003)。
文摘Two viologen derivatives containing fluorine substituent(F)with an asymmetric structures,1,1'-bis(4-(trifluoromethyl)phenyl)-[4,4'-bipyridine]dihexafluorophosphate(DFPV)and 1-benzyl-1'-(4-(trifluoromethyl)phenyl)-[4,4'-bipyridine]di-hexafluorophosphate(Bn-FPV),were synthesized.These viologen derivatives as active materials were used to assemble both flexible and rigid electrochromic devices(ECDs).ECDs based on DFPV exhibited reversible color change from colorless to deep green and ECDs based on Bn-FPV exhibited reversible color change from colorless to blue-green within applied voltage.It was found that the devices based on DFPV showed cycle stability,which could still maintain more than 90% after 1000 cycles.In addition,the modulation rate of the device to the solar irradiance is also calculated to characterize its application potential in smart windows.Among them,the rigid device(R-DFPV)based on the DFPV has a large solar irradiance modulation rate of 54.66%,which has the potential to be used as smart windows.
基金support from the National Natural Science Foundation of China(Grant No.62105148)China Postdoctoral Science Foundation(2022TQ0148 and 2023M731651)Postgraduate Research&Practice Innovation Program of NUAA(xcxjh20230609).
文摘Dual-band electrochromic devices capable of the spectral-selective modulation of visible(VIS)light and near-infrared(NIR)can notably reduce the energy consumption of buildings and improve the occupants’visual and thermal comfort.However,the low optical modulation and poor durability of these devices severely limit its practical applications.Herein,we demonstrate an efficient and flexible bifunctional dual-band electrochromic device which not only shows excellent spectral-selective electrochromic performance with a high optical modulation and a long cycle life,but also displays a high capacitance and a high energy recycling efficiency of 51.4%,integrating energy-saving with energy-storage.The nanowires structure and abundant oxygen-vacancies of oxygen-deficient tungsten oxide nanowires endows it high flexibility and a high optical modulation of 73.1%and 85.3%at 633 and 1200 nm respectively.The prototype device assembled can modulate the VIS light and NIR independently and effectively through three distinct modes with a long cycle life(3.3%capacity loss after 10,000 cycles)and a high energy-saving performance(8.8℃lower than the common glass).Furthermore,simulations also demonstrate that our device outperforms the commercial low-emissivity glass in terms of energy-saving in most climatic zones around the world.Such windows represent an intriguing potential technology to improve the building energy efficiency.
文摘Electrochromic(EC)smart windows utilizing a reversible metal electrodeposition device(RMED)offer a compelling alternative for dynamically regulating transmissions of optical and thermal energy.An EC device(ECD)is constructed by reversible metal electrodeposition(RME)of Bi/Cu on WO_(3)·xH_(2)O film electrodeposited onto fluorine-doped tin oxide(FTO)transparent conductive glass.The electrolyte consists of CuCl_(2),BiCl_(3),KCl and HCl aqueous solution,supplying necessary components for both electrochemical and electrodeposition processes.The ECD shows ability to rapidly transition between colorless and black states,which achieves a large optical modulation of 77.0%at 570 nm.In the black state,the ECD exhibits a near-zero transmittance in the wavelength range of 400-1100 nm while maintaining 96.6%of its initial optical modulation after coloration/bleaching cycling of 60000 s,exhibiting good cyclic stability.This RMED has relatively high stability under open-circuit voltage and also possesses excellent heat insulation performance.The results offer a solution to overcome the poor cyclic stability of RMEDs and improve the optical modulation of ECDs.
基金supported by the Singapore National Research Foundation(NRFCRP26-2021-0003,NRF),for research conducted at the National University of Singaporethe support by the ARTIC(ADT-RP2-Low Loss and Tunable Ferroelectrics for Sub-6G Applications).
文摘Sodium-ion-based electrochromic device(SECD)has been identified as an appealing cost-effective alternative of lithium-based counterparts,only if it can address the challenges in association with the inadequate electrochromic performance.In this regard,the quantized strategy is a particularly promising approach owing to the large surface-to-volume ratio and high reaction activity.However,quantum dots inevitably suffer from volume changes and undesired aggregation during electrochemical cycling.Herein,bioinspired from the robust connection of alveoli in lung,we propose a stable electrode,where WO_(3) quantum dots(WQDs)are robustly anchored on Ti_(3)C_(2) MXene through the strong chemical bonds of W-O-Ti.Theoretical results reveal the fundamental mechanism of the volume changes within WQDs and the dynamic diffusion process of sodium ions.The WQD@MXene electrodes exhibit a nearly twofold enhancement in cycling performance(1000 vs 500 cycles),coloration speed(3.2 vs 6.0 s),and areal capacity(87.5 vs 43.9 mAhm^(-2) at 0.1 mA cm^(-2)),compared to those of the pristine WQD electrode.As a proof-of-concept demonstration,a smart house system integrated with SECDs demonstrates a“3-in-1”device,enabling a combination of energy-saving,energy storage,and display functionalities.The present work significantly advances the versatile applications of cost-effective electrochromic electronics in interdisciplinary.
基金supported by the National Natural Science Foundation of China(No.22174055)Key R&D Program of Zhenjiang City(No.NY2022012)。
文摘Wearable flexible sensor devices have the characteristics of lightweight and miniaturization.Currently,power supply and detection components limit the portability of wearable flexible sensor devices.Meanwhile,conventional liquid electrolytes are unsuitable for the integration of sensing devices.To address these constraints,wearable biofuel cells and flexible electrochromic displays have been introduced,which can improve integration with other devices,safety,and color-coded display data.Meanwhile,electrode chips prepared through screen printing technology can further improve portability.In this work,a wearable sensor device with screen-printed chips was constructed and used for non-invasive detection of glucose.Agarose gel electrolytes doped with PDA-CNTs were prepared,and the mechanical strength and moisture retention were significantly improved compared with traditional gel electrolytes.Glucose in interstitial fluid was non-invasive extracted to the skin surface using reverse iontophoresis.As a biofuel for wearable biofuel cells,glucose drives self-powered sensor and electrochromic display to produce color change,allowing for visually measurement of glucose levels in body fluids.Accurate detection results can be visualized by reading the RGB value with a cell phone.
基金supported by the National Natural Science Foundation of China(Nos.52163022 and 62305076)Guizhou Provincial Education Department Youth Science and Technology Talent Development project(No.KY2022-136)+3 种基金Guizhou Science and Technology Plan General Program(No.ZK2022-155)China Postdoctoral Science Foundation(No.2023M740505)Sichuan Science and Technology Program(No.2024ZYD0196)Sichuan Postdoctoral Science Special Foundation(No.TB2023010)
文摘Traditional electrodes for flexible/wearable electrochromic zinc ion batteries(EC-ZIBs)are typically prepared using electrodeposition or hydrothermal methods which suffer from poor adhesion,leading to significan performance degradation during repeated bending.In this paper,a Prussian blue electrode with MXene(MPB elec trode)-assisted in situ growth was prepared by the two-dimensional-material-assisted in situ growth(TAIG)method.The MPB electrode,achieved through simple immersion,features a nanoparticle shape with strong bonding to the flexible substrate.This nanoparticle-shaped PB does not clog the pores of the nylon fibers and grows inside the nylon fibers,which ultimately shortens the ion channels,allowing short ion diffusion pathways,fas electrochemical kinetics,favorable electrolyte penetration and improved specific capacity.In the fabrication of EC-ZIB devices,the MPB cathode exhibits a high specific capacity of 197.2 mAh g^(-1)at 2 A g^(-1)and retains 79.7%of its capacity even with a tenfold increase in current density.Additionally,the MPB electrode demonstrates excellent electrochromic performance(yellow,green and blue)within the range of 0.5 to 1.8 V,with rapid switching time of only 2.2 s for coloring and 2.0 s for bleaching.Therefore,the MPB electrodes fulfill the requirements for multifunctional devices,allowing easy monitoring of energy storage levels through color changes,and showing potential applications in smart camouflage,wearable displays and other fields,promoting the development of flexible smart energy storage devices.
基金supported by the Natural Science Foundation of Jiangxi Province(20232ACB204002&20232BAB202044)Jiangxi Provincial Key Laboratory of Flexible Electronics(20212BCD42004&20242BCC32010).
文摘Flexible electrochromic devices(FECDs)demonstrate significant potential for applications in wearable elec-tronics,military camouflage,and flexible smart displays.As a crucial electrochromic material,poly(3,4-ethylenedioxythiophene):polystyrene sulfonate(PEDOT:PSS)is widely used in FECDs due to its excellent mechanical flexibility,tunable conductivity,and non-toxicity.However,the manufacturing process for patterned PEDOT:PSS electrochromic devices remains intricate,costly,and challenging to personalize.To address this challenge,we have developed a 3D-printable ink with controllable rheological properties through a concentration-tuning strategy,enabling programmable,patterned printing of PEDOT-based conductive polymer electrochromic layers.The 3D-printed FECDs exhibit outstanding electrochromic performance,including a high optical contrast(up to 47.9%at 635 nm),fast response times(t_(c)=1.6 s;t_(b)=0.6 s),high coloration efficiency(352 cm^(2) C^(-1)),and good cycling stability(with only a 9.3%decrease in optical contrast after 100 electrochemical cycles).Finally,we utilize 3D printing technology to construct flexible,patterned PEDOT:PSS electrochromic devices with bespoke butterfly designs.This work establishes the theoretical foundation for the application of 3D printing technology in PEDOT:PSS flexible electrochromic devices.
基金financially supported by the National Natural Science Foundation of China(No.62471271)Shandong Provincial Natural Science Foundation(No.ZR2021YQ42)the Taishan Young Scholar Program of Shandong Province
文摘Vanadium oxide(VO_(X))with tunable interlayer spacing and variable valence states of vanadium ions offers tremendous opportunities in aqueous electrochromic devices but is still challenging.Herein,a poly aniline(PANI)-VO_(X)composite material has been designed,increasing the conductivity and the structure stability.Owning to these virtues,the PANI-VO_(X)composite material achieves a high capacitance of 332 mAh·g^(-1)at 0.1 A·g^(-1)and a superior cycling performance(72%ΔT retention after 500 cycles).Importantly,in-situ Raman spectroscopy has been utilized to reveal the rapid formation of Zn_(3)(OH)_(2)V_(2)O_(7)·nH_(2)O and the reversible change of PANI-VO_(X),which can further assist the development of aqueous electrochromic devices.This work highlights the understanding of the Zn^(2+)electrochromic mechanism and sheds some light on organic-inorganic composite electrochromic materials.
基金the National Natural Science Foundation of China(No.52272009)the Henan Provincial Science and Technology Research Project(No.242102230151)+1 种基金the Henan Provincial University Science and Technology Innovation Team(No.25IRTSTHN009)the Key Scientific Research Projects of Colleges and Universities in Henan Province(Nos.24B560021,25B560020,25B560023)。
文摘This paper adopted the hydrothermal method to prepare tungsten oxide(WO_(3))nanorod films and studied the effects of precursor solution concentration(0.02,0.03,0.06 mol/L peroxytungstic acid)and annealing temperature(200,300,400℃)on their electrochromic properties.The microstructure characterization of WO_(3) films were performed using scanning electron microscope(SEM),X-ray diffraction(XRD),and transmission electron microscope(TEM),and their electrochromic properties were tested by combining an electrochemical workstation with an ultraviolet-visible spectrophotometer.The results showed that the precursor solution concentration directly affected the thickness(290,560,990 nm)and microstructure of WO_(3) films,significantly impacting their electrochromic properties.However,the annealing temperature had a negligible effect.As the precursor solution concentration increased,the optical modulation of WO_(3) films gradually decreased,reaching 51.1%,43.8%,and 35.1%,respectively.The switching time first increased and then stabilized,with coloring times of 7.3,7.7,and 7.7 s,respectively,and bleaching times of 3.8,6.5,and 6.5 s,respectively.The coloration efficiency gradually increased but the increase was relatively small,reaching 41.8,44.4,and 44.8 cm^(2)/C,respectively.Moreover,the cycling stability of WO_(3) films was poor,with the ratios of the final value of optical modulation to the initial value 0.33,0.26,and 0.34,respectively.Additionally,there were bigger differences in the bleached state transmittance,while the colored state transmittance showed smaller variations.However,the former has better cycling stability than the latter.In summary,to obtain better electrochromic properties,the thickness of WO_(3) films should not exceed 290 nm.
基金the National Natural Science Foundation of China(52072096)The Natural Science Foundation of Heilongjiang Province(LH2023E034).
文摘Electrochromism is the process by which a material applies a small electrical signal to change the optical properties(transmittance,reflectance,absorptivity and emissivity)of the material reversibly or permanently through REDOX reactions resulting from ion and electron embedding/ejection.Metal-organic framework(MOF)are advantageous materials for electrochromic application due to their high porosity,large specific surface area and orderly pore structure,that promotes the adsorption of electrolyte ions,ion diffusion and charge transfer.In addition,MOFs possess a variety of ligands and metal centers,allowing for design of composition types and pore structure sizes.This grants them the advantages of both organic electrochromic materials,such as vivid colors and fast color transformation,and inorganic electrochromic materials,like high coloring efficiency and excellent stability.This paper reviews the current research progress of MOF electrochromic materials,including materials design,electrochromic properties,and application.
基金supported by the National Natural Science Foundation of China (51902064)the Scientific and Technological Bases and Talents of Guangxi (2019AC20198)+2 种基金Guangxi Natural Science Foundation (2017GXNSFGA198005)the special fund for “Guangxi Bagui Scholars”the “Guangxi Hundred-Talent Program”。
文摘Zinc-anode-based electrochromic devices(ZECDs) are emerging as the next-generation energy-e cient transparent electronics. We report anatase W-doped TiO_(2) nanocrystals(NCs) as a Zn^(2+) active electrochromic material. It demonstrates that the W doping in TiO_(2) highly reduces the Zn^(2+) intercalation energy,thus triggering the electrochromism. The prototype ZECDs based on W-doped TiO_(2) NCs deliver a high optical modulation(66% at 550 nm),fast spectral response times(9/2.7 s at 550 nm for coloration/bleaching),and good electrochemical stability(8.2% optical modulation loss after 1000 cycles).
文摘The high quality TiO2, MoO3-doped WO3 electrochromic film was prepared by the sol-gel method for the first time.The sol, which has hydrogen peroxide （H2O2） and oxalic acid （H2C2O4）, was very stable at room temperature and quite suitable for the deposition of films. The WO3 electrochromic film prepared from this doped sol had excellent performance, such as short response time, no cracks, good adhesion to the substrate, high coloring efficiency and longevity of service.
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This work was financially supported by the Chongqing Natural Science Foundation of China （CSTC, 2005BB4109）.
文摘Abstract： A new compound 1-ethyl-1＇-（4-vinylbenzyl）-4, 4＇-bipyridinium chloride and iodide has been synthesized. The cyclic voltammogram and impedance spectra indicated that a layer of viologen＇s electrochromic （EC） film could be deposited on conductive ITO glass working electrode With polyelectrolyte as ionic conduction layer, solid EC devices based on this compound have been assembled and their thickness was about 2.35 mm. When different voltages were added, they showed blue or violet red color. After optimization, its response time was less than 50 ms, the number of redox circulation was over 107 and the color of coloration states could be kept for 3 days. This kind of EC device can meet the demand of electronic ink.
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the National Science Foundation of China(Nos.61631166004 and 51902250)the Fundamental Research Funds for the Central Universities(xzy012019002)+2 种基金H.F.thanks the support from Natural Science Basic Research Plan in Shaanxi Province of China(No.2020JQ-035)H.W.acknowledged the support of Shenzhen Science and Technology Program(No.KQTD20180411143514543)Shenzhen DRC project[2018]1433.
文摘Electrochromic technology plays a significant role in energy conservation,while its performance is greatly limited by the transport behavior of ions and electrons.Hence,an electrochromic system with overall excellent performances still need to be explored.Initially motivated by the high ionic and electronic conductivity of transition metal carbide or nitride(MXene),we design a feasible procedure to synthesize the MXene/WO3−x composite electrochromic film.The consequently boosted electrochromic performances prove that the addition of MXene is an effective strategy for simultaneously enhancing electrons and ions transport behavior in electrochromic layer.The MXene/WO3−x electrochromic device exhibits enhanced transmittance modulation and coloration efficiency(60.4%,69.1 cm^2 C^−1),higher diffusion coefficient of Li+and excellent cycling stability(200 cycles)over the pure WO3−x device.Meanwhile,numerical stimulation theoretically explores the mechanism and kinetics of the lithium ion diffusion,and proves the spatial and time distributions of higher Li+concentration in MXene/WO3−x composite electrochromic layer.Both experiments and theoretical data reveal that the addition of MXene is effective to promote the transport kinetics of ions and electrons simultaneously and thus realizing a high-performance electrochromic device.This work opens new avenues for electrochromic materials design and deepens the study of kinetics mechanism of ion diffusion in electrochromic devices.
文摘In this study,novel electrochromic copolymers of 3,4-ethylenedioxythiophene(EDOT)and(E)-1,2-bis(2-fluoro-4-(4-hexylthiophen-2-yl)phenyl)diazene(M1)with different monomer feed ratios were designed and synthesized electrochemically.Electrochemical and spectroelectrochemical characterizations were performed using voltammetry and UV-Vis-NIR spectrophotometry techniques to test the applicability of copolymers for electrochromic applications.In terms of electrochemical behaviors,addition of an electron-rich EDOT unit into the azobenzenecontaining copolymer increased the electron density on the polymer chain and afforded copolymers with very low oxidation potentials at around0.30 V.While the homopolymers(P1 and PEDOT)exhibited neutral state absorptions centered at 510 and 583 nm,EDOT-bearing copolymers showed red shifted absorptions compared to those of P1 with narrower optical band gaps.In addition,the poor optical contrast and switching times of azobenzene-bearing homopolymer were significantly improved with EDOT addition into the copolymer chain.As a result of the promising electrochromic and kinetic preperties,Co P1.5-bearing single layer electrochromic device that works between purple and light greenish blue colors was constructed and characterized.
基金financially supported by the National Natural Science Foundation of China(Nos.51373049,51372055,21372067,21206034,51303045 and 51473046)Doctoral Fund of Ministry of Education of China(Nos.20132301120004 and 20132301110001)Reserve Talented Person of Harbin(No.2015RAXXJ015)
文摘Five novel near-infrared electrochromic aromatic polyimides （PIs） with pendent benzimidazole group were synthesized from 4,4＇-diamino-4＂-（1-benzylbenzimidazol-2-yl）triphenylamine （named as DBBT） with five different dianhydrides via two-step polymerization process, respectively. The maximum UV-Vis absorption bands of these PIs locate at about 335 nm for solid films due to the π-π＊ transitions. A reversible pair of distinct redox peaks, that were associated with a noticeable color change from original yellow to blue, was observed in the cyclic voltammetry （CV） test. A new absorption peak emerged at 847 nm in near-infrared （NIR） region with increasing voltage in UV-Vis-NIR spectrum, which indicates that PI can be used as NIR electrochromic material. These novel PIs have good electrochemical stability, appropriate energy levels for the highest occupied molecular orbital （HOMO） and the lowest unoccupied molecular orbital （LUMO）, in the range of-5.17 eV to -5.20 eV and -2.14 eV to -2.26 eV （versus the vacuum level） determined by cyclic voltammetry method. These values basically consisted with the results of quantum chemical calculation. These polyimides can be used as novel electrochromic and hole transportation materials.
基金support by the"Thailand Science Research and Innovation(TSRI)under Fundamental Fund 2022"(Sustainable Energy&EnvironmentTheme).
文摘This research concerns the development of lithium ions conductive electrolyte from poly(vinyl butyral)(PVB)resin for use as a special interlayer film in electrochromic glass.To obtain the final PVB film with high ionic conductivity and thermal stability,a masterbatch was firstly prepared by mixing of PVB resin with lithium salt(LiClO_(4))and additives in an aqueous ethanol solution.After this,the dried masterbatch were converted into final films by an extrusion process.In this study,PVB film with the highest ionic conductivity value of 4.85×10^(-6) was obtained when the masterbatch was diluted with the neat PVB resin at the weight ratio of 2:1 in the extruder prior to fabrication.The results from cyclic voltammetry over 100 cycles,showed that performance of the electrochromic device(ITO/WO_(3)/PVB electrolyte/ITO)fabricated by using the above PVB film is stable and reversible.In overall,this work demonstrates that ion conductive PVB films with compromised ionic conductivity and thermal stability can be prepared via an extrusion process without the need to modify chemical structure of PVB.This was carried out through the masterbatch approach,by introducing (LiClO_(4)) salts into the plasticized PVB via a solution mixing process prior to converting it into a final film via the extrusion process.
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.
