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
CONSPECTUS:Thermoresponsive hydrogels possess an inherent capacity for autonomous adjustment of their properties in response to temperature variations,eliminating the requirement for external power sources and renderi...CONSPECTUS:Thermoresponsive hydrogels possess an inherent capacity for autonomous adjustment of their properties in response to temperature variations,eliminating the requirement for external power sources and rendering them suitable for diverse environmental applications.Our discourse commences by establishing a foundational comprehension of the two principal categories governing thermal transitions in thermoresponsive hydrogels,namely,the Lower Critical Solution Temperature(LCST)and the Upper Critical Solution Temperature(UCST).展开更多
In recent years,thermochromic smart windows have played an important role in enhancing energy efficiency and contributing to carbon neutrality in building energy consumption.However,thermal-shielding smart windows wit...In recent years,thermochromic smart windows have played an important role in enhancing energy efficiency and contributing to carbon neutrality in building energy consumption.However,thermal-shielding smart windows with high visible light modulation and structural colors are rarely reported.This study focuses on the development of thermochromic smart windows utilizing poly(N-isopropylacrylamide)(PNIPAm)-based nanogels,which exhibit dynamic solar modulation and high visible light transmission without additional energy input.Unlike traditional electrochromic materials such as tungsten trioxide,these smart windows achieve structural color states through the self-assembly of nanogels,eliminating the need for inorganic materials.The fabricated hydrogel contains thermo-responsive poly(N-isopropylacrylamide-random-acrylic acid-random-N-tert-butyl acrylamide)P(NIPAm-r-AA-r-TBA)(PNTA)nanogels with tunable phase transition temperatures(Tp)that align with ambient conditions.These smart windows demonstrate excellent stability over 100 heating-cooling cycles and significant temperature regulation,achieving an indoor temperature modulation of 10℃and energy savings of 14.24 KJ m^(-3)compared with normal windows.The production process is simple and scalable,making it feasible for industrial applications.Furthermore,these smart windows offer additional functionalities such as information encryption,adding value to their practical application.展开更多
Smart windows are an important strategy to reduce the energy consumption in buildings,which accounts for as much as 30%e40%of the society's energy consumption.VO_(2)-based thermochromic materials can intelligently...Smart windows are an important strategy to reduce the energy consumption in buildings,which accounts for as much as 30%e40%of the society's energy consumption.VO_(2)-based thermochromic materials can intelligently regulate the solar heat gains of building interiors.However,the unmatched thermal emissivity(ε)modulation of traditional VO_(2)/glass systems,i.e.,high emissivity at low temperatures and low emissivity at high temperatures,leads to additional heating and cooling energy loads in winter and summer,respectively.In this study,we propose a novel VO_(2)/polyacrylonitrile(PAN)/AgNW multilayer possessing flexible Ag nanowire supported FabryePerot cavities,which synchronously achieves high modulation abilities in both solar spectrum(DT_(sol) of 13.6%)and middle infrared region(D 3 of 0.50 at 8-13 mm).These achievements are the best among reports for pure VO_(2) smart windows.This study provides a flexible and effective protocol to dynamically enhance the light and heat utilization for practical building windows.展开更多
With the rapid development of optoelectronics,electrochromic(EC)materials(ECMs)with the advan-tages of low power consumption,easy viewing,high contrast ratio,etc have attached more and more attention from the fields o...With the rapid development of optoelectronics,electrochromic(EC)materials(ECMs)with the advan-tages of low power consumption,easy viewing,high contrast ratio,etc have attached more and more attention from the fields of smart windows,electronic billboards,emerging wearable and portable electronics,and other next-generation displays.Nickel oxide(NiO)is a promising candidate for high-performance ECMs because of its neutral-colored states and low cost.However,NiO-based ECMs still face the problem of slow switching speed due to their low electrical conductivity and small lattice spacing.Metal-organic frameworks(MOFs)are promising candidates to fabricate hollow and porous transition metal oxides(TMOs)with high ion transport efficiency,excellent specific capacitance,and electrochemical activities.In this work,porous yolk-shell NiO nanospheres(PYS-NiO NSs)were syn-thesized via a solvothermal and subsequent calcination process of Ni-MOF,which exhibited outstanding EC performance.Because the large specific surface areas and hollow porous nanostructures were conducive to ionic transport,PYS-NiO NSs exhibited a fast coloring/bleaching speed(3.6/3.9 s per one coloring/bleaching cycle)and excellent cycling stability(82%of capacity retention after 3000 cycles).These superior EC properties indicated that the PYS-NiO NSs was a promising candidate for high-performance EC devices.This work provides a new and feasible strategy for the efficient preparation of TMOs ECMs with good EC performance,especially fast switching speed.展开更多
Thermochromic smart windows have gained increasing popularity in light modulation and energy management in buildings.However,the fabrication of flexible thermochromic smart windows with high luminous transmittance(Tlu...Thermochromic smart windows have gained increasing popularity in light modulation and energy management in buildings.However,the fabrication of flexible thermochromic smart windows with high luminous transmittance(Tlum),tailorable critical temperature(τc),strong solar modulation ability(ΔTsol),and long-term durability remains a huge challenge.In this study,hydrogel-based thermochromic smart windows are fabricated by sandwiching thermochromic hydrogels of polyallylamine hydrochloride,polyacrylic acid,and carbonized polymer dots(CPDs)complexes between two pieces of transparent substrates.Benefiting from the incorporation of nanosized CPDs,the thermochromic hydrogel has an ultrahigh Tlum of~98.7%,a desirableτc of~24.2℃,aΔTsol of~89.3%and a rapid transition time of~3 s from opaque state to transparent state.Moreover,the thermochromic hydrogel exhibits excellent anti-freezing ability,tight adhesion toward various substrates,and excellent self-healing capability.The self-healing capability enables the fabrication of large-area smart windows by welding multiple hydrogel pieces.The smart windows retain their original thermochromic properties after being stored under ambient conditions for at least 147 days or undergoing 10,000 uninterrupted heating/cooling cycles.The model houses with smart windows can achieve a temperature reduction of 9.2℃,demonstrating the excellent indoor temperature modulation performance of the smart windows.展开更多
Internationally,standards for electrochromic(EC)requirements in smart window applications have been established,with ongoing global initiatives aimed at elevating them to highly advanced levels.This paper covers a com...Internationally,standards for electrochromic(EC)requirements in smart window applications have been established,with ongoing global initiatives aimed at elevating them to highly advanced levels.This paper covers a comprehensive investigation of the structural,optical,morphological,and electrochemical properties of WO_(3)/TiO_(2)composite films.Simultaneously,an experimental analysis of WO_(3)/TiO_(2)was envisaged by a two-step process.Initially,WO_(3)thin films were hydrothermally deposited onto indium-doped tin oxide-coated glass substrates using an aqueous solution of Na_(2)WO_(4)·2H_(2)O at a pH value of 1.Subsequently,a layer of TiO_(2)was electrodeposited onto the WO_(3)thin films.X-ray diffraction analysis confirmed the successful formation of WO_(3)/TiO_(2)composite films,with the WO_(3)phase exhibiting a hexagonal tunnel structure.Scanning electron microscopy revealed the formation of porous nanorods(NRs)of WO_(3),uniformly coated with TiO_(2),resulting in a porous morphology of the WO./TiO_(2)samples.The EC performance of the WO_(3)/TiO_(2)films was thoroughly assessed through cyclic voltammetry and chronoamperometry measurements over a potential window ranging from-2.0 to+1.2 V(versus Ag/AgCl)in a 0.5 mol·L^(-1)LiClO_(4)-PC electrolyte.The WO_(3)/TiO_(2)composite films exhibited cathodic electrochromism,characterized by a reversible color change from dark blue to transparent.This improved EC performance in comparison to pure WO_(3)films is attributed to enhanced double ion/electron insertion and extraction efficiency.Furthermore,the WO_(3)/TiO_(2)composite films demonstrated excellent optical modulation properties,with a significant modulation at 633 nm(46.87%).The coloration efficiency reached a high value of 193.25 cm^(2)·C^(-1),indicating their potential for practical EC applications.Moreover,the WO_(3)/TiO_(2)composite films displayed exceptional EC stability,with no significant degradation observed over 2500 cyclic voltammetry cycles.This superior EC performance can be attributed to the synergistic effect between the hexagonal WO_(3)NRs and anatase TiO_(2).This study highlights the significance of the synthesis method and the unique structural characteristics of the composite in enhancing the EC performance.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
Electrochromic smart windows have attracted much attention in energy-saving buildings because of their ability to selectively modulate visible(VIS)and near-infrared(NIR)light transmittance.As is known,the NIR region a...Electrochromic smart windows have attracted much attention in energy-saving buildings because of their ability to selectively modulate visible(VIS)and near-infrared(NIR)light transmittance.As is known,the NIR region accounts for about 50%of the total solar radiation.Therefore,reducing the NIR transmittance of windows will play a crucial role in reducing the energy consumption of buildings.However,for most of the reported electrochromic materials(ECMs)-based windows,it remains a longlasting challenge about how to achieve a low NIR transmittance during the past decades.In this work,we synthesize oxygendeficient tungsten oxide(WO_(3−x))nanoflowers(NFs)by a simple and efficient method that is facile for their mass production.The WO_(3−x)NFs exhibit low NIR transmittance of only 4.11%,0.60%,and 0.19%at 1200,1600,and 1800 nm,respectively,due to the localized surface plasmon resonance(LSPR)effect.Besides,the WO_(3−x)NFs exhibit an excellent dual-band modulating ability for both VIS and NIR light.They are able to operate in three distinct modes,including a bright mode,a cool mode,and a dark mode.Moreover,the WO_(3−x)NFs exhibit a fast bleaching/coloring time(1.54/6.67 s),and excellent cycling stability(97.75%of capacity retention after 4000 s).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
Thermochromic hydrogel smart windows represent a significant breakthrough in the field of building energy conservation,offering a revolutionary solution for intelligent thermal environment management through their abi...Thermochromic hydrogel smart windows represent a significant breakthrough in the field of building energy conservation,offering a revolutionary solution for intelligent thermal environment management through their ability to dynamically regulate solar transmittance.This review systematically summarizes the thermoresponsive properties and technical bottlenecks of thermochromic hydrogels in smart window applications.A comprehensive analysis of the advantages and limitations of this class of material in terms of phase transition temperature,optical performance,stability,and response speed is provided,while the progresses made in optimizing their performance through various strategies are discussed.As a prospect,in the future,the development of thermochromic hydrogel smart windows must prioritize broad-temperature adaptability,cost-effectiveness,and multifunctional integration to address current challenges and facilitate their widespread adoption and scientific innovation in building energy conservation.展开更多
Smart windows with tunable optical properties that respond to external environments are being developed to reduce energy consumption in buildings.In the present study,we introduce a new type of 3D printed hydrogel wit...Smart windows with tunable optical properties that respond to external environments are being developed to reduce energy consumption in buildings.In the present study,we introduce a new type of 3D printed hydrogel with amazing flexibility and stretchability(as large as 1500%),as well as tunable optical performance controlled by surrounding temperatures.The hydrogel on a PDMS substrate shows transparent-opaque transition with high solar modulation(ΔT_(sol))up to 79.332% around its lower critical solution temperature(L_(CST))while maintaining a high luminous transmittance(T_(lum))of 85.847% at 20℃.In addition,selective transparent-opaque transition above LCST can be achieved by patterned hydrogels which are precisely fabricated via a projection micro-stereolithography based 3D printing technique.Our hydrogel promises great potential applications for the next generation of soft smart windows.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
To ensure the safety of residents’lives and property by using automatic opening and closing of ordinary windows,this article designs an intelligent window automatic monitoring system.The article proposes a software a...To ensure the safety of residents’lives and property by using automatic opening and closing of ordinary windows,this article designs an intelligent window automatic monitoring system.The article proposes a software and hardware design scheme for the system,which comprises a microcontroller control module,temperature and humidity detection module,harmful gas detection module,rainfall detection module,human thermal radiation induction module,Organic Light-Emitting Diode(OLED)display module,stepper motor drive module,Wi-Fi communication module,etc.Users use this system to monitor environmental data such as temperature,humidity,rainfall,harmful gas concentrations,and human health.Users can control the opening and closing of windows through manual,microcontroller,and mobile application(app)remote methods,providing users with a more convenient,comfortable,and safe living environment.展开更多
A new gelator(BAzo-Chol)comprising a diazocine core and two cholesterol units linked via carbamate groups has been designed and synthesized.Its gelation ability in several kinds of organic solvents is identified.Inves...A new gelator(BAzo-Chol)comprising a diazocine core and two cholesterol units linked via carbamate groups has been designed and synthesized.Its gelation ability in several kinds of organic solvents is identified.Investigations with scanning electron microscopy(SEM),transmission electron microscopy(TEM),rheological measurements,and UV-vis absorption and 1H NMR spectroscopy reveal that BAzo-Chol can self-assemble into elastically interpenetrating one-dimensional nanostructures in organogels through a cooperative effect of theπ-πinteractions,hydrogen-bonding,and van der Waals forces.Moreover,the unconventional Z/E conformational transitions of these organogels,due to the inclusion of diazocine,endow the BAzo-Chol gels with excellent photo-responsive gel-sol transition and remarkable visible light-induced chromic properties.Lastly,due to its sensitive response to visible light accompanied by distinct changes in both colour and transparency of the gel-sol transitions,the potential application of the current gelator in smart windows is signified.展开更多
Smart windows,capable of dynamically regulating indoor heat,offer a promising avenue for effectively reducing energy consumption.Hydrogel-based smart windows are excellent at thermal modulation and daylighting,but the...Smart windows,capable of dynamically regulating indoor heat,offer a promising avenue for effectively reducing energy consumption.Hydrogel-based smart windows are excellent at thermal modulation and daylighting,but they are difficult to commercialize globally due to problems like winter ice formation,which can affect thermal insulation,daylighting,and structural integrity,as well as an impractical cloud point temperature(t_(cp)).To solve these issues,a ternary anti-freezing system consisting of ethylene glycol(EG),glycerol,and water is proposed.With the t_(cp)regulated at 31.6℃,the system strikes a balance between outstanding daylighting(91.89%)and solar modulation ability(78.32%).Furthermore,the system shows resilience even below-30.0℃and long-term stability,which qualifies it for use in densely populated regions even with severely cold weather.To further illustrate the distinct impacts of EG and glycerol,the optical characteristics and tcpof binary systems containing EG and water as well as glycerol and water were examined.The durability test includes severely cold temperature of-30.0℃ and solar exposure temperature of 60.0℃.This work would offer insights to advance the field's understanding of antifreezing capability modification in smart windows and advance the development of environmentally and energy-efficiently designed buildings.展开更多
Windows are essential to let natural daylight into our buildings.Smart and dynamic glazing is an important technology for achieving sustainable and energy-efficient buildings with good indoor environment by reducing t...Windows are essential to let natural daylight into our buildings.Smart and dynamic glazing is an important technology for achieving sustainable and energy-efficient buildings with good indoor environment by reducing the need for air-conditioning.Electrochromic glazing is the commercial state-of-the-art for smart and dynamic glazing.In principle electrochromic glazing works like a thin film battery,whose lifetime is enhanced if the combination of elevated temperature and a high state-of-charge,or low light transmittance,are avoided.Therefore,a direct transmittance measurement is desirable.In this study,we have evaluated four different methods using optical fibers,whereof two methods were found to work well,both in initial testing and when compared to reference transmittance cycling measurements.Both methods relied on light from a light emitting diode,at 810 nm wavelength,that was propagated either through the electrochromic foil or along it.The latter shows most potential to be implemented in a manufacturing process of smart glazing.展开更多
Buildings are responsible for over 40% of total primary energy consumption in the US and EU and therefore improving building energy efficiency has significant potential for obtaining net-zero energy buildings reducing...Buildings are responsible for over 40% of total primary energy consumption in the US and EU and therefore improving building energy efficiency has significant potential for obtaining net-zero energy buildings reducing energy consumption. The concurrent demands of environmental comfort and the need to improve energy efficiency for both new and existing buildings have motivated research into finding solutions for the regulation of incoming solar radiation, as well as ensuring occupant thermal and visual comfort whilst generating energy onsite. Windows as building components offer the opportunity of addressing these issues in buildings. Building integration of photovoltaics permits building components such as semi-transparent façade, skylights and shading devices to be replaced with PV. Much progress has been made in photovoltaic material science, where smart window development has evolved in areas such as semi-transparent PV, electrochromic and thermochromic materials, luminescent solar concentrator and the integration of each of the latter technologies to buildings, specifically windows. This paper presents a review on intelligent window technologies that integrate renewable energy technologies with energy-saving strategies contributing potential solutions towards sustainable zero-energy buildings. This review is a comprehensive evaluation of intelligent windows focusing on state-of-the-art development in windows that can generate electricity and their electrical, thermal and optical characteristics. This review provides a summary of current work in intelligent window design for energy generation and gives recommendations for further research opportunities.展开更多
Windows are one of the least energy-efficient components of a building.It allows energy to escape,leading to high cooling demand in summer and energy loss in winter.Sunlight and temperature in the building also affect...Windows are one of the least energy-efficient components of a building.It allows energy to escape,leading to high cooling demand in summer and energy loss in winter.Sunlight and temperature in the building also affect people's health,comfort,and even productivity.As a result,controlling the heat and light entering the building dynamically is critical for improving the comfort of building occupants and reducing energy consumption.In this work,we develop a tunable smart window based on transparent dielectric elastomer actuators(DEAs)as an alternative solution to sunlight and temperature control.The transparency-tuning is achieved by creating wrinkles in a soft elastomer film made of waterborne polyurethane(WPU).The actuation mechanism is based on highly transparent dielectric elastomer actuators that use all solid-state stretchable transparent conductive polymer poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)/(PEDOT:PSS/WPU)as compliant electrodes.The modulation range of the smart tunable window with direct viewing is achieved to be 35%to 90%,which is one of the largest among existing tunable windows.At the low-transparency state,the window can also effectively block the heat and decrease the temperature rise to 2℃over 200 s,while the ambient temperature rises by 6℃with direct sunlight.We anticipate that this transparency-tuning mechanism is potentially useful for privacy protection,smart glass,projector screens,displays,and camouflage.The heat isolation feature also has the potential to reduce carbon emissions and improve the sustainability of buildings and greenhouses.展开更多
Intelligent responsive devices are crucial for a variety of applications ranging from smart electronics to robotics.Electro-responsive cholesteric liquid crystals(CLC)have been widely applied in display panels,smart w...Intelligent responsive devices are crucial for a variety of applications ranging from smart electronics to robotics.Electro-responsive cholesteric liquid crystals(CLC)have been widely applied in display panels,smart windows,and so on.In this work,we realize the mechanical stimuli-triggered optical responses of the CLC by integrating it with a triboelectric nanogenerator(TENG),which converts the mechanical motion into alternating current electricity and then tunes the different optical responses of the CLC.When the voltage applied on the CLC is relatively low(15–40 V),the TENG drives the switching between the bistable planar state and focal conic state of the CLC,which shows potential applications in selfpowered smart windows or E-paper displays.When the voltage supplied by the TENG is larger than60 V,a self-powered optical switch is demonstrated by utilizing the transformation between focal conic state and instantons homeotropic state of the CLC.This triboelectric-optical responsive device consumes no extra electric power and suggests a great potential for future smart electronics.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funding support from the Global STEM Professorship Scheme sponsored by the Government of Hong Kong Special Administrative RegionStart-up funding from The Chinese University of Hong Kong.
文摘CONSPECTUS:Thermoresponsive hydrogels possess an inherent capacity for autonomous adjustment of their properties in response to temperature variations,eliminating the requirement for external power sources and rendering them suitable for diverse environmental applications.Our discourse commences by establishing a foundational comprehension of the two principal categories governing thermal transitions in thermoresponsive hydrogels,namely,the Lower Critical Solution Temperature(LCST)and the Upper Critical Solution Temperature(UCST).
基金supported by the Fundamental Research Funds for the Central Universities(2232022A-07)the National Natural Science Foundation of China(52173157)。
文摘In recent years,thermochromic smart windows have played an important role in enhancing energy efficiency and contributing to carbon neutrality in building energy consumption.However,thermal-shielding smart windows with high visible light modulation and structural colors are rarely reported.This study focuses on the development of thermochromic smart windows utilizing poly(N-isopropylacrylamide)(PNIPAm)-based nanogels,which exhibit dynamic solar modulation and high visible light transmission without additional energy input.Unlike traditional electrochromic materials such as tungsten trioxide,these smart windows achieve structural color states through the self-assembly of nanogels,eliminating the need for inorganic materials.The fabricated hydrogel contains thermo-responsive poly(N-isopropylacrylamide-random-acrylic acid-random-N-tert-butyl acrylamide)P(NIPAm-r-AA-r-TBA)(PNTA)nanogels with tunable phase transition temperatures(Tp)that align with ambient conditions.These smart windows demonstrate excellent stability over 100 heating-cooling cycles and significant temperature regulation,achieving an indoor temperature modulation of 10℃and energy savings of 14.24 KJ m^(-3)compared with normal windows.The production process is simple and scalable,making it feasible for industrial applications.Furthermore,these smart windows offer additional functionalities such as information encryption,adding value to their practical application.
基金supported in part by funding from the National Natural Science Foundation of China(NSFC,Contract Nos.:51502268,51325203)the Open Project of State Key Laboratory of Advanced Special Steel,Shanghai Key Laboratory of Advanced Ferrometallurgy,Shanghai University(SKLASS 2022e04)+1 种基金the Science and Technology Commission of Shanghai Municipality(No.19DZ2270200)the Provincial and Ministerial Co-construction of Collaborative Innovation Center for Resource Materials(Contract No.:zycl202008).
文摘Smart windows are an important strategy to reduce the energy consumption in buildings,which accounts for as much as 30%e40%of the society's energy consumption.VO_(2)-based thermochromic materials can intelligently regulate the solar heat gains of building interiors.However,the unmatched thermal emissivity(ε)modulation of traditional VO_(2)/glass systems,i.e.,high emissivity at low temperatures and low emissivity at high temperatures,leads to additional heating and cooling energy loads in winter and summer,respectively.In this study,we propose a novel VO_(2)/polyacrylonitrile(PAN)/AgNW multilayer possessing flexible Ag nanowire supported FabryePerot cavities,which synchronously achieves high modulation abilities in both solar spectrum(DT_(sol) of 13.6%)and middle infrared region(D 3 of 0.50 at 8-13 mm).These achievements are the best among reports for pure VO_(2) smart windows.This study provides a flexible and effective protocol to dynamically enhance the light and heat utilization for practical building windows.
基金supported by the Tsinghua-Toyota Joint Research Fund,National Key Research Program(grant Nos.2020YFA0210702 and 2020YFC2201103)the National Natural Science Foundation of China(grant Nos.51872156 and 22075163)China Postdoctoral Science Foundation funded project(grant No.2022M721808).
文摘With the rapid development of optoelectronics,electrochromic(EC)materials(ECMs)with the advan-tages of low power consumption,easy viewing,high contrast ratio,etc have attached more and more attention from the fields of smart windows,electronic billboards,emerging wearable and portable electronics,and other next-generation displays.Nickel oxide(NiO)is a promising candidate for high-performance ECMs because of its neutral-colored states and low cost.However,NiO-based ECMs still face the problem of slow switching speed due to their low electrical conductivity and small lattice spacing.Metal-organic frameworks(MOFs)are promising candidates to fabricate hollow and porous transition metal oxides(TMOs)with high ion transport efficiency,excellent specific capacitance,and electrochemical activities.In this work,porous yolk-shell NiO nanospheres(PYS-NiO NSs)were syn-thesized via a solvothermal and subsequent calcination process of Ni-MOF,which exhibited outstanding EC performance.Because the large specific surface areas and hollow porous nanostructures were conducive to ionic transport,PYS-NiO NSs exhibited a fast coloring/bleaching speed(3.6/3.9 s per one coloring/bleaching cycle)and excellent cycling stability(82%of capacity retention after 3000 cycles).These superior EC properties indicated that the PYS-NiO NSs was a promising candidate for high-performance EC devices.This work provides a new and feasible strategy for the efficient preparation of TMOs ECMs with good EC performance,especially fast switching speed.
基金supported by the National Natural Science Foundation of China (No.21935004).
文摘Thermochromic smart windows have gained increasing popularity in light modulation and energy management in buildings.However,the fabrication of flexible thermochromic smart windows with high luminous transmittance(Tlum),tailorable critical temperature(τc),strong solar modulation ability(ΔTsol),and long-term durability remains a huge challenge.In this study,hydrogel-based thermochromic smart windows are fabricated by sandwiching thermochromic hydrogels of polyallylamine hydrochloride,polyacrylic acid,and carbonized polymer dots(CPDs)complexes between two pieces of transparent substrates.Benefiting from the incorporation of nanosized CPDs,the thermochromic hydrogel has an ultrahigh Tlum of~98.7%,a desirableτc of~24.2℃,aΔTsol of~89.3%and a rapid transition time of~3 s from opaque state to transparent state.Moreover,the thermochromic hydrogel exhibits excellent anti-freezing ability,tight adhesion toward various substrates,and excellent self-healing capability.The self-healing capability enables the fabrication of large-area smart windows by welding multiple hydrogel pieces.The smart windows retain their original thermochromic properties after being stored under ambient conditions for at least 147 days or undergoing 10,000 uninterrupted heating/cooling cycles.The model houses with smart windows can achieve a temperature reduction of 9.2℃,demonstrating the excellent indoor temperature modulation performance of the smart windows.
基金supported by the Human Resources Development Program(No.20194030202470)of the Korea Institute of Energy Technology EvaluationPlanning(KETEP)with the support of the Korean Government Ministry of Trade,Industry and Energythe Department of Science and Technology,India,under the DST-FIST(SR/FST/PSI173/2012)program。
文摘Internationally,standards for electrochromic(EC)requirements in smart window applications have been established,with ongoing global initiatives aimed at elevating them to highly advanced levels.This paper covers a comprehensive investigation of the structural,optical,morphological,and electrochemical properties of WO_(3)/TiO_(2)composite films.Simultaneously,an experimental analysis of WO_(3)/TiO_(2)was envisaged by a two-step process.Initially,WO_(3)thin films were hydrothermally deposited onto indium-doped tin oxide-coated glass substrates using an aqueous solution of Na_(2)WO_(4)·2H_(2)O at a pH value of 1.Subsequently,a layer of TiO_(2)was electrodeposited onto the WO_(3)thin films.X-ray diffraction analysis confirmed the successful formation of WO_(3)/TiO_(2)composite films,with the WO_(3)phase exhibiting a hexagonal tunnel structure.Scanning electron microscopy revealed the formation of porous nanorods(NRs)of WO_(3),uniformly coated with TiO_(2),resulting in a porous morphology of the WO./TiO_(2)samples.The EC performance of the WO_(3)/TiO_(2)films was thoroughly assessed through cyclic voltammetry and chronoamperometry measurements over a potential window ranging from-2.0 to+1.2 V(versus Ag/AgCl)in a 0.5 mol·L^(-1)LiClO_(4)-PC electrolyte.The WO_(3)/TiO_(2)composite films exhibited cathodic electrochromism,characterized by a reversible color change from dark blue to transparent.This improved EC performance in comparison to pure WO_(3)films is attributed to enhanced double ion/electron insertion and extraction efficiency.Furthermore,the WO_(3)/TiO_(2)composite films demonstrated excellent optical modulation properties,with a significant modulation at 633 nm(46.87%).The coloration efficiency reached a high value of 193.25 cm^(2)·C^(-1),indicating their potential for practical EC applications.Moreover,the WO_(3)/TiO_(2)composite films displayed exceptional EC stability,with no significant degradation observed over 2500 cyclic voltammetry cycles.This superior EC performance can be attributed to the synergistic effect between the hexagonal WO_(3)NRs and anatase TiO_(2).This study highlights the significance of the synthesis method and the unique structural characteristics of the composite in enhancing the EC performance.
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the Tsinghua-Toyota Joint Research Fund,the National Key Research Program(Nos.2020YFA0210702 and 2020YFC2201103)the National Natural Science Foundation of China(Nos.51872156 and 22075163)the China Postdoctoral Science Foundation funded project(No.2022M721808).
文摘Electrochromic smart windows have attracted much attention in energy-saving buildings because of their ability to selectively modulate visible(VIS)and near-infrared(NIR)light transmittance.As is known,the NIR region accounts for about 50%of the total solar radiation.Therefore,reducing the NIR transmittance of windows will play a crucial role in reducing the energy consumption of buildings.However,for most of the reported electrochromic materials(ECMs)-based windows,it remains a longlasting challenge about how to achieve a low NIR transmittance during the past decades.In this work,we synthesize oxygendeficient tungsten oxide(WO_(3−x))nanoflowers(NFs)by a simple and efficient method that is facile for their mass production.The WO_(3−x)NFs exhibit low NIR transmittance of only 4.11%,0.60%,and 0.19%at 1200,1600,and 1800 nm,respectively,due to the localized surface plasmon resonance(LSPR)effect.Besides,the WO_(3−x)NFs exhibit an excellent dual-band modulating ability for both VIS and NIR light.They are able to operate in three distinct modes,including a bright mode,a cool mode,and a dark mode.Moreover,the WO_(3−x)NFs exhibit a fast bleaching/coloring time(1.54/6.67 s),and excellent cycling stability(97.75%of capacity retention after 4000 s).
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).
基金supported by the National Natural Science Foundation of China(No.52373169).
文摘Thermochromic hydrogel smart windows represent a significant breakthrough in the field of building energy conservation,offering a revolutionary solution for intelligent thermal environment management through their ability to dynamically regulate solar transmittance.This review systematically summarizes the thermoresponsive properties and technical bottlenecks of thermochromic hydrogels in smart window applications.A comprehensive analysis of the advantages and limitations of this class of material in terms of phase transition temperature,optical performance,stability,and response speed is provided,while the progresses made in optimizing their performance through various strategies are discussed.As a prospect,in the future,the development of thermochromic hydrogel smart windows must prioritize broad-temperature adaptability,cost-effectiveness,and multifunctional integration to address current challenges and facilitate their widespread adoption and scientific innovation in building energy conservation.
基金supported by the National Natural Science Foundation of China (52006056)Key-Area Research and Development Program of Guangdong Province (2020B090923003)+1 种基金Civil Aerospace Technology Research Project (B0108)Natural Science Foundation of Hunan through Grant No. 2020JJ3012
文摘Smart windows with tunable optical properties that respond to external environments are being developed to reduce energy consumption in buildings.In the present study,we introduce a new type of 3D printed hydrogel with amazing flexibility and stretchability(as large as 1500%),as well as tunable optical performance controlled by surrounding temperatures.The hydrogel on a PDMS substrate shows transparent-opaque transition with high solar modulation(ΔT_(sol))up to 79.332% around its lower critical solution temperature(L_(CST))while maintaining a high luminous transmittance(T_(lum))of 85.847% at 20℃.In addition,selective transparent-opaque transition above LCST can be achieved by patterned hydrogels which are precisely fabricated via a projection micro-stereolithography based 3D printing technique.Our hydrogel promises great potential applications for the next generation of soft smart windows.
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.
文摘To ensure the safety of residents’lives and property by using automatic opening and closing of ordinary windows,this article designs an intelligent window automatic monitoring system.The article proposes a software and hardware design scheme for the system,which comprises a microcontroller control module,temperature and humidity detection module,harmful gas detection module,rainfall detection module,human thermal radiation induction module,Organic Light-Emitting Diode(OLED)display module,stepper motor drive module,Wi-Fi communication module,etc.Users use this system to monitor environmental data such as temperature,humidity,rainfall,harmful gas concentrations,and human health.Users can control the opening and closing of windows through manual,microcontroller,and mobile application(app)remote methods,providing users with a more convenient,comfortable,and safe living environment.
基金supported by the National Key R&D Program of China(Nos.2023YFB3609000 and 2022YFF1202902)the National Natural Science Foundation of China(Nos.22275068 and 21975178).
文摘A new gelator(BAzo-Chol)comprising a diazocine core and two cholesterol units linked via carbamate groups has been designed and synthesized.Its gelation ability in several kinds of organic solvents is identified.Investigations with scanning electron microscopy(SEM),transmission electron microscopy(TEM),rheological measurements,and UV-vis absorption and 1H NMR spectroscopy reveal that BAzo-Chol can self-assemble into elastically interpenetrating one-dimensional nanostructures in organogels through a cooperative effect of theπ-πinteractions,hydrogen-bonding,and van der Waals forces.Moreover,the unconventional Z/E conformational transitions of these organogels,due to the inclusion of diazocine,endow the BAzo-Chol gels with excellent photo-responsive gel-sol transition and remarkable visible light-induced chromic properties.Lastly,due to its sensitive response to visible light accompanied by distinct changes in both colour and transparency of the gel-sol transitions,the potential application of the current gelator in smart windows is signified.
基金supported by the Key Research and Development Program-Guidance Project of Heilongjiang Province of China(Grant No.GZ20210150)。
文摘Smart windows,capable of dynamically regulating indoor heat,offer a promising avenue for effectively reducing energy consumption.Hydrogel-based smart windows are excellent at thermal modulation and daylighting,but they are difficult to commercialize globally due to problems like winter ice formation,which can affect thermal insulation,daylighting,and structural integrity,as well as an impractical cloud point temperature(t_(cp)).To solve these issues,a ternary anti-freezing system consisting of ethylene glycol(EG),glycerol,and water is proposed.With the t_(cp)regulated at 31.6℃,the system strikes a balance between outstanding daylighting(91.89%)and solar modulation ability(78.32%).Furthermore,the system shows resilience even below-30.0℃and long-term stability,which qualifies it for use in densely populated regions even with severely cold weather.To further illustrate the distinct impacts of EG and glycerol,the optical characteristics and tcpof binary systems containing EG and water as well as glycerol and water were examined.The durability test includes severely cold temperature of-30.0℃ and solar exposure temperature of 60.0℃.This work would offer insights to advance the field's understanding of antifreezing capability modification in smart windows and advance the development of environmentally and energy-efficiently designed buildings.
文摘Windows are essential to let natural daylight into our buildings.Smart and dynamic glazing is an important technology for achieving sustainable and energy-efficient buildings with good indoor environment by reducing the need for air-conditioning.Electrochromic glazing is the commercial state-of-the-art for smart and dynamic glazing.In principle electrochromic glazing works like a thin film battery,whose lifetime is enhanced if the combination of elevated temperature and a high state-of-charge,or low light transmittance,are avoided.Therefore,a direct transmittance measurement is desirable.In this study,we have evaluated four different methods using optical fibers,whereof two methods were found to work well,both in initial testing and when compared to reference transmittance cycling measurements.Both methods relied on light from a light emitting diode,at 810 nm wavelength,that was propagated either through the electrochromic foil or along it.The latter shows most potential to be implemented in a manufacturing process of smart glazing.
基金supported by Consejo Nacional de Ciencia y Tecnología (CONACyT) through a PhD studentship awarded to Manlio Salas Castillosupported by the Engineering and Physical Sciences Research Council, UK [grant number EP/S030786/1].
文摘Buildings are responsible for over 40% of total primary energy consumption in the US and EU and therefore improving building energy efficiency has significant potential for obtaining net-zero energy buildings reducing energy consumption. The concurrent demands of environmental comfort and the need to improve energy efficiency for both new and existing buildings have motivated research into finding solutions for the regulation of incoming solar radiation, as well as ensuring occupant thermal and visual comfort whilst generating energy onsite. Windows as building components offer the opportunity of addressing these issues in buildings. Building integration of photovoltaics permits building components such as semi-transparent façade, skylights and shading devices to be replaced with PV. Much progress has been made in photovoltaic material science, where smart window development has evolved in areas such as semi-transparent PV, electrochromic and thermochromic materials, luminescent solar concentrator and the integration of each of the latter technologies to buildings, specifically windows. This paper presents a review on intelligent window technologies that integrate renewable energy technologies with energy-saving strategies contributing potential solutions towards sustainable zero-energy buildings. This review is a comprehensive evaluation of intelligent windows focusing on state-of-the-art development in windows that can generate electricity and their electrical, thermal and optical characteristics. This review provides a summary of current work in intelligent window design for energy generation and gives recommendations for further research opportunities.
基金the support from the Singapore Institute of Manufacturing Technology(SIMTech),Agency for Science,Technology and Research(A*STAR),Singaporethe support from the Chinese University of Hong Kong,Shenzhen(Grant No.UDF01001987)Shenzhen Institute of Artificial Intelligence and Robotics for Society(Grant No.AC01202101113)。
文摘Windows are one of the least energy-efficient components of a building.It allows energy to escape,leading to high cooling demand in summer and energy loss in winter.Sunlight and temperature in the building also affect people's health,comfort,and even productivity.As a result,controlling the heat and light entering the building dynamically is critical for improving the comfort of building occupants and reducing energy consumption.In this work,we develop a tunable smart window based on transparent dielectric elastomer actuators(DEAs)as an alternative solution to sunlight and temperature control.The transparency-tuning is achieved by creating wrinkles in a soft elastomer film made of waterborne polyurethane(WPU).The actuation mechanism is based on highly transparent dielectric elastomer actuators that use all solid-state stretchable transparent conductive polymer poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)/(PEDOT:PSS/WPU)as compliant electrodes.The modulation range of the smart tunable window with direct viewing is achieved to be 35%to 90%,which is one of the largest among existing tunable windows.At the low-transparency state,the window can also effectively block the heat and decrease the temperature rise to 2℃over 200 s,while the ambient temperature rises by 6℃with direct sunlight.We anticipate that this transparency-tuning mechanism is potentially useful for privacy protection,smart glass,projector screens,displays,and camouflage.The heat isolation feature also has the potential to reduce carbon emissions and improve the sustainability of buildings and greenhouses.
基金supported by the National Key Research and Development Program of China(2016YFA0202702)the Youth Innovation Promotion Association of CAS。
文摘Intelligent responsive devices are crucial for a variety of applications ranging from smart electronics to robotics.Electro-responsive cholesteric liquid crystals(CLC)have been widely applied in display panels,smart windows,and so on.In this work,we realize the mechanical stimuli-triggered optical responses of the CLC by integrating it with a triboelectric nanogenerator(TENG),which converts the mechanical motion into alternating current electricity and then tunes the different optical responses of the CLC.When the voltage applied on the CLC is relatively low(15–40 V),the TENG drives the switching between the bistable planar state and focal conic state of the CLC,which shows potential applications in selfpowered smart windows or E-paper displays.When the voltage supplied by the TENG is larger than60 V,a self-powered optical switch is demonstrated by utilizing the transformation between focal conic state and instantons homeotropic state of the CLC.This triboelectric-optical responsive device consumes no extra electric power and suggests a great potential for future smart electronics.
