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
The original version of this article unfortunately contained some mistakes in figure. The authors found that explanation of the data lines in Fig. 5b is wrong.The corrected version of Fig. 5b is given below:Open Acces...The original version of this article unfortunately contained some mistakes in figure. The authors found that explanation of the data lines in Fig. 5b is wrong.The corrected version of Fig. 5b is given below:Open AccessThis article is licensed under a Creative Commons Attribution 4.0 International License,which permits use,sharing,adaptation,distribution and reproduction in any medium or format,as long as you give appropriate credit to the original author(s) and the source,provide a link to the Creative Commons licence.展开更多
Thermoelectric power generation provides us the unique capability to explore the deep space and holds promise for harvesting the waste heat and providing a battery-free power supply for IoTs.The past years have witnes...Thermoelectric power generation provides us the unique capability to explore the deep space and holds promise for harvesting the waste heat and providing a battery-free power supply for IoTs.The past years have witnessed massive progress in thermoelectric materials,while the module-level development is still lagged behind.We would like to shine some light on the module-level design and characterization of thermoelectric power generators(TEGs).In the module-level design,we review material selection,thermal management,and the determination of structural parameters.We also look into the module-level characterization,with particular attention on the heat flux measurement.Finally,the challenge in the optimal design and reliable characterization of thermoelectric power generators is discussed,together with a calling to establish a standard test procedure.展开更多
Recently,flexible oxide epitaxial thin films are of increasing interests owing to their excellent physical properties and wide applications.The oxide epitaxial thin films with flexible,lightweight and wearable are pro...Recently,flexible oxide epitaxial thin films are of increasing interests owing to their excellent physical properties and wide applications.The oxide epitaxial thin films with flexible,lightweight and wearable are promising for the applications in flexible and wearable devices,such as flexible sensors,flexible detectors,flexible oscillators,flexible spintronics,wearable displays and electronic skin,etc.This review aims to summarize the fabrication,physical properties and applications of the flexible oxide epitaxial thin films for wearable electronics in most recent few years.The fabrication of flexible oxide epitaxial thin films reviewed here mainly includes the deposition on flexible substrates at high temperature and epitaxial lift-off(ELO)from rigid substrates.The physical properties and applications of flexible oxide epitaxial thin films reviewed here chiefly focus on the area of electricity and magnetism,including stable and tunable physical properties in the flexible oxide epitaxial thin films.In final,the perspectives and challenges of flexible oxide thin films for wearable electronics have been also addressed.展开更多
Flexible polymer thermoelectric thin film attracts wide attentions because it is compatible with the wearable electronics and e-skin.Herein,we reported an enhanced thermoelectric power factor of PEDOT:PSS from around...Flexible polymer thermoelectric thin film attracts wide attentions because it is compatible with the wearable electronics and e-skin.Herein,we reported an enhanced thermoelectric power factor of PEDOT:PSS from around 1 μWm^(-1) K^(-2) to 117 μWm^(-1) K^(-2) and high substrate-free strain of 20% through synergistically tuning the ordering structure and the oxidation state.An ionic liquid(EMImTCM)was used to decouple the ionic interaction between PEDOT and PSS,rearranging the morphology of structure that significantly benefit the mechanical flexibility and the electrical conductivity.The addition of Lascorbic acid was confirmed as effective dedoping additive of PEDOT polymer that changed the oxidation state and hence boosted the thermoelectric power factor without notable sacrifice of the mechanical flexibility.Moreover,the electrical conductivity of the corresponding film maintained electrically stable(ΔR/R_(0)<0.12%)under 1000 bending cycles which indicates the great bendability.Our work demonstrated the feasibility to controllably tailor the thermoelectric and mechanical performance of the PEDOT:PSS flexible polymer thermoelectric thin film.展开更多
The past years has observed a significantly boost of the thermoelectric materials in the scale of thermoelectric figure-of-merit,i.e.ZT,because of its promising application to harvest the widely distributed waste heat...The past years has observed a significantly boost of the thermoelectric materials in the scale of thermoelectric figure-of-merit,i.e.ZT,because of its promising application to harvest the widely distributed waste heat.However,the simplified thermoelectric materials'performance scale also shifted the focus of thermoelectric energy conversion technique from devices-related efforts to materials-level works.As a result,the thermoelectric devices-related works didn't get enough attention.The device-level challenges behind were kept unknown until recent years.However,besides the thermoelectric materials properties,the practical energy conversion efficiency and service life of thermoelectric device is highly determined by assembling process and the contact interface.In this perspective,we are trying to shine some light on the device-level challenge,and give a special focus on the thermoelectric interface materials(TEiM)between the thermoelectric elements and electrode,which is also known as the metallization layer or solder barrier layer.We will go through the technique concerns that determine the scope of the TEiM,including bonding strength,interfacial resistance and stability.Some general working principles are summarized before the discussion of some typical examples of searching proper TEiM for a given thermoelectric conversion material.展开更多
In this work,the(1-x)CaWO_(4)-xNa_(2)WO_(4)(x=0.1,0.2,denoted as 0.9CW-0.1NW and 0.8CW-0.2NW,respectively)ultralow-loss microwave dielectric ceramics were prepared via solid-state reaction method.Using low melting-poi...In this work,the(1-x)CaWO_(4)-xNa_(2)WO_(4)(x=0.1,0.2,denoted as 0.9CW-0.1NW and 0.8CW-0.2NW,respectively)ultralow-loss microwave dielectric ceramics were prepared via solid-state reaction method.Using low melting-point Na_(2)WO_(4) as sintering aid to prepare CaW_(O4)eNa_(2)WO_(4) composite ceramics,the sintering temperature of CaWO_(4) was successfully reduced while maintaining excellent microwave performance.The optimal microwave dielectric properties have been achieved at 900C for 0.9CW-0.1NW ceramic:εr=9.0,Q×f=105660 GHz,tandδ=1.1×10^(-4)and tf=35.4 ppm/℃ at a frequency of 12.0 GHz.For the 0.8CW-0.2NW ceramic,the optimal microwave dielectric properties have been obtained at 740C,withεr=8.5,Q×f=97014 GHz,tandδ=1.2×10^(-4)and tf=37.4 ppm/℃ at a frequency of 11.8 GHz.In summary,both composite ceramics exhibit low sintering temperatures,excellent dielectric properties and chemical compatibility with the Ag electrode.The findings of this study provide an effective approach to prepare novel composite ceramics as promising candidates for LTCC applications.展开更多
Ionic thermoelectric(i-TE)technologies can power Internet of Things(IoT)sensors by harvesting thermal energy from the environment because of their large thermopowers.Present research focuses mostly on using the intera...Ionic thermoelectric(i-TE)technologies can power Internet of Things(IoT)sensors by harvesting thermal energy from the environment because of their large thermopowers.Present research focuses mostly on using the interactions between ions and matrices to enhance i-TE performance,but i-TE materials can benefit from utilizing different methods to control ion transport.Here,we introduced a new strategy that employs an ion entanglement effect.A giant thermopower of 28 mV K^(-1)was obtained in a quasi-solid-state i-TE Gelatin-CF_(3)SO_(3)K–CH_(3)SO_(3)K gel via entanglement between CF_(3)SO_(3)^(-)and CH_(3)SO_(3)^(-)anions.The anionic entanglement effect involves complex interactions between these two anions,slowing anionic thermodiffusion and thus suppressing bipolar effects and boosting p-type thermopower.A Au@Cu|Gelatin-CF_(3)SO_(3)K–CH_(3)SO_(3)K|Au@Cu i-TE device with a generator mode delivers a specific output energy density of 67.2 mJ m^(-2)K^(-2)during 2 h of discharging.Long-term operation.展开更多
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The original version of this article unfortunately contained some mistakes in figure. The authors found that explanation of the data lines in Fig. 5b is wrong.The corrected version of Fig. 5b is given below:Open AccessThis article is licensed under a Creative Commons Attribution 4.0 International License,which permits use,sharing,adaptation,distribution and reproduction in any medium or format,as long as you give appropriate credit to the original author(s) and the source,provide a link to the Creative Commons licence.
基金supported by Shenzhen DRC project(Grant No.[2018]1433)。
文摘Thermoelectric power generation provides us the unique capability to explore the deep space and holds promise for harvesting the waste heat and providing a battery-free power supply for IoTs.The past years have witnessed massive progress in thermoelectric materials,while the module-level development is still lagged behind.We would like to shine some light on the module-level design and characterization of thermoelectric power generators(TEGs).In the module-level design,we review material selection,thermal management,and the determination of structural parameters.We also look into the module-level characterization,with particular attention on the heat flux measurement.Finally,the challenge in the optimal design and reliable characterization of thermoelectric power generators is discussed,together with a calling to establish a standard test procedure.
基金supported by the National Science Foundation of China(No.61631166004)Shenzhen KQTD project(No.KQTD20180411143514543)+1 种基金Shenzhen JCYJ project(No.JCYJ20180504165831308)and Shenzhen DRC project[2018]1433partially supported by Doctoral Scientific Research Startup Foundation of Shaanxi University of Science and Technology(No.2019BJ-30).
文摘Recently,flexible oxide epitaxial thin films are of increasing interests owing to their excellent physical properties and wide applications.The oxide epitaxial thin films with flexible,lightweight and wearable are promising for the applications in flexible and wearable devices,such as flexible sensors,flexible detectors,flexible oscillators,flexible spintronics,wearable displays and electronic skin,etc.This review aims to summarize the fabrication,physical properties and applications of the flexible oxide epitaxial thin films for wearable electronics in most recent few years.The fabrication of flexible oxide epitaxial thin films reviewed here mainly includes the deposition on flexible substrates at high temperature and epitaxial lift-off(ELO)from rigid substrates.The physical properties and applications of flexible oxide epitaxial thin films reviewed here chiefly focus on the area of electricity and magnetism,including stable and tunable physical properties in the flexible oxide epitaxial thin films.In final,the perspectives and challenges of flexible oxide thin films for wearable electronics have been also addressed.
基金supported by the Guangdong Innovative and Entrepreneurial Research Team Program,China[grant numbers NO.2016ZT06G587]Shenzhen Science Technology Fund,China[grant numbers NO.KYDPT20181011104007]Shenzhen DRC project,China[2018]1433.
文摘Flexible polymer thermoelectric thin film attracts wide attentions because it is compatible with the wearable electronics and e-skin.Herein,we reported an enhanced thermoelectric power factor of PEDOT:PSS from around 1 μWm^(-1) K^(-2) to 117 μWm^(-1) K^(-2) and high substrate-free strain of 20% through synergistically tuning the ordering structure and the oxidation state.An ionic liquid(EMImTCM)was used to decouple the ionic interaction between PEDOT and PSS,rearranging the morphology of structure that significantly benefit the mechanical flexibility and the electrical conductivity.The addition of Lascorbic acid was confirmed as effective dedoping additive of PEDOT polymer that changed the oxidation state and hence boosted the thermoelectric power factor without notable sacrifice of the mechanical flexibility.Moreover,the electrical conductivity of the corresponding film maintained electrically stable(ΔR/R_(0)<0.12%)under 1000 bending cycles which indicates the great bendability.Our work demonstrated the feasibility to controllably tailor the thermoelectric and mechanical performance of the PEDOT:PSS flexible polymer thermoelectric thin film.
基金the support of National Key Project of Research and Development Plan No.2018YFB0703600NSFC program No.51872133 and 51572282Guangdong Innovative and Entrepreneurial Research Team Program,No.2016ZT06G578.
文摘The past years has observed a significantly boost of the thermoelectric materials in the scale of thermoelectric figure-of-merit,i.e.ZT,because of its promising application to harvest the widely distributed waste heat.However,the simplified thermoelectric materials'performance scale also shifted the focus of thermoelectric energy conversion technique from devices-related efforts to materials-level works.As a result,the thermoelectric devices-related works didn't get enough attention.The device-level challenges behind were kept unknown until recent years.However,besides the thermoelectric materials properties,the practical energy conversion efficiency and service life of thermoelectric device is highly determined by assembling process and the contact interface.In this perspective,we are trying to shine some light on the device-level challenge,and give a special focus on the thermoelectric interface materials(TEiM)between the thermoelectric elements and electrode,which is also known as the metallization layer or solder barrier layer.We will go through the technique concerns that determine the scope of the TEiM,including bonding strength,interfacial resistance and stability.Some general working principles are summarized before the discussion of some typical examples of searching proper TEiM for a given thermoelectric conversion material.
基金This work was supported by Key Area Research Plan of Guangdong(Grant No.2020B010176001)the Shenzhen Science and Technology Program(Nos.KQTD20180411143514543 and JCYJ20180504165831308)Shenzhen DRC project[2018]1433.
文摘In this work,the(1-x)CaWO_(4)-xNa_(2)WO_(4)(x=0.1,0.2,denoted as 0.9CW-0.1NW and 0.8CW-0.2NW,respectively)ultralow-loss microwave dielectric ceramics were prepared via solid-state reaction method.Using low melting-point Na_(2)WO_(4) as sintering aid to prepare CaW_(O4)eNa_(2)WO_(4) composite ceramics,the sintering temperature of CaWO_(4) was successfully reduced while maintaining excellent microwave performance.The optimal microwave dielectric properties have been achieved at 900C for 0.9CW-0.1NW ceramic:εr=9.0,Q×f=105660 GHz,tandδ=1.1×10^(-4)and tf=35.4 ppm/℃ at a frequency of 12.0 GHz.For the 0.8CW-0.2NW ceramic,the optimal microwave dielectric properties have been obtained at 740C,withεr=8.5,Q×f=97014 GHz,tandδ=1.2×10^(-4)and tf=37.4 ppm/℃ at a frequency of 11.8 GHz.In summary,both composite ceramics exhibit low sintering temperatures,excellent dielectric properties and chemical compatibility with the Ag electrode.The findings of this study provide an effective approach to prepare novel composite ceramics as promising candidates for LTCC applications.
基金supported by the Shenzhen Natural Science Funds for Distinguished Young Scholar(No.RCJC20210706091949018)the Shenzhen Sci-Tech Fund(KYTDPT20181011104007)+2 种基金the Shenzhen DRC project([2018]1433)the Guangdong Innovative and Entrepreneurial Research Team Program Project(2016ZT06G587)the Tencent Foundation through the XPLORER PRIZE,and the Centers for Mechanical Engineering Research and Education at MIT and SUSTech.
文摘Ionic thermoelectric(i-TE)technologies can power Internet of Things(IoT)sensors by harvesting thermal energy from the environment because of their large thermopowers.Present research focuses mostly on using the interactions between ions and matrices to enhance i-TE performance,but i-TE materials can benefit from utilizing different methods to control ion transport.Here,we introduced a new strategy that employs an ion entanglement effect.A giant thermopower of 28 mV K^(-1)was obtained in a quasi-solid-state i-TE Gelatin-CF_(3)SO_(3)K–CH_(3)SO_(3)K gel via entanglement between CF_(3)SO_(3)^(-)and CH_(3)SO_(3)^(-)anions.The anionic entanglement effect involves complex interactions between these two anions,slowing anionic thermodiffusion and thus suppressing bipolar effects and boosting p-type thermopower.A Au@Cu|Gelatin-CF_(3)SO_(3)K–CH_(3)SO_(3)K|Au@Cu i-TE device with a generator mode delivers a specific output energy density of 67.2 mJ m^(-2)K^(-2)during 2 h of discharging.Long-term operation.