To obtain a stable amplified spontaneous emission（ASE） source for complex environment applications, we design an ASE source and study the output power and spectral characteristics under different ambient temperature...To obtain a stable amplified spontaneous emission（ASE） source for complex environment applications, we design an ASE source and study the output power and spectral characteristics under different ambient temperatures.We optimize the structure of the ASE source to flatten the ASE spectrum, and study the output characteristics in terms of output power and optical spectrum under different pump powers. Then the performance of the ASE source is investigated in the temperature range from-18.9°C to 50°C. A stable-power and flat-spectrum ASE source can be obtained by structural optimization and pump control.展开更多
Recently,application-oriented strain sensor has been intensively investigated in the fields of human motion detection,personalized health management and portable medical diagnosis.Despite significant efforts in improv...Recently,application-oriented strain sensor has been intensively investigated in the fields of human motion detection,personalized health management and portable medical diagnosis.Despite significant efforts in improving its sensitivity and linear sensing range,developing the wearable strain sensor with stable signal remains a challenge.Herein,we proposed an ideal hybrid material with nearly zero temperature coefficient resistance(TCR)for temperature-insensitive strain sensing:the silver nanostructures(AgNTs)were introduced to coat the graphene foam(GrF)conformably by hydrothermal growth.The nanoscaled metal additives(TCR>0)not only endow GrF(TCR<0)with high electrical stability(TCR≈-0.3×10^(-3)℃^(-1)),but also offer the hybrid system additional structural elasticity,potential for next-generation of portable,stretchable and reliable devices.The resultant AgNTs@GrF hybrid material has been processed into a piezoresistive sensor with excellent sensing accuracy(strain error<2.7%),satisfactory gauge factor(GF)of227,wide sensing range up to 90%and good cyclic stability(>3000 cycles).Moreover,our strain sensor can be easily mounted on human skin as an epidermal device for reliable detection of electrophysiological stimuli,thus showing a great promising in practical wearable applications.展开更多
Persistent operation inevitably elevates the temperature of perovskite solar cells(PSCs),posing a challenge for maximizing their power output and stability even after effective defect passivation and encapsulation tec...Persistent operation inevitably elevates the temperature of perovskite solar cells(PSCs),posing a challenge for maximizing their power output and stability even after effective defect passivation and encapsulation techniques have been implemented.Regulating the thermal conductivity of halide perovskites by additive engineering is now a mainstream strategy for achieving self-cooling devices,but our fundamental understanding of how perovskites with atomic disorder function remains insufficient.This theoretical study unveils the underlying mechanism of facet-dependent thermodynamic properties in mixed-cation perovskites.The results demonstrate that the(100)facet has higher thermal conductivity than the(110)and(111)facets.By carefully controlling the(100)crystallographic orientation through buried and bulk modification,the thermal conductivity of the target perovskite film can be increased from 1.005 to 1.068 W m^(-1)K^(-1),which lowers the PSC's equilibrium temperature 5.25℃by accelerating heat transport and dissipation.Consequently,we achieve an inverted PSC with an excellent efficiency of 25.12%,accompanied by a significantly reduced temperature coefficient and better long-term stability:a conservation rate exceeding 90%after aging at 85℃and exposure to persistent light irradiation for 1100 h.This work elucidates a previously unidentified outcome of crystal facet engineering:the achievement of thermal management in high-performance PSCs.展开更多
Elastomer composites with stable electrical conductivity are crucial for the reliable operation of advanced flexible electronic devices under temperature variations or various deformations.However,current materials st...Elastomer composites with stable electrical conductivity are crucial for the reliable operation of advanced flexible electronic devices under temperature variations or various deformations.However,current materials struggle to simultaneously maintain stable conductivity during significant thermal shocks or mechanical deformations.To address this challenge,we propose a general strategy for constructing temperature/deformation-insensitive conductive pathways by leveraging a liquid metal(LM)/polymer bicontinuous phase network.Based on the communicating vessellike structure of the material,the material enables selfadaptive interfacial void filling through solid–liquid cooperative deformation mechanisms,thereby maintaining conductive pathways under elevated temperatures or mechanical strains.At low temperatures,the LM undergoes expansion to establish new conductive channels,which reduces the material’s electrical resistance and ensures excellent conductivity in cryogenic environments.As a proof of concept,the elastomer exhibits exceptional and stable conductivity(σ298 K=500 S/cm)under drastic thermal shocks(ΔT=410 K).Furthermore,the material demonstrates minimal resistance variation under diverse deformations,with only a 1.2%increase in resistance under 170%tensile strain.Additionally,the composite maintains nearly invariant ultra-broadband electromagnetic shielding performance and stable thermal conductivity at elevated temperatures.This work provides a strategy for the design and fabrication of flexible conductive elastomers capable of stable operation in complex extreme environments.展开更多
With the increasing advance of fifth generation(5G)network and the gradual expansion of digital devices,harsh working environment for electronic devices has spawned higher requirements for microwave absorbing material...With the increasing advance of fifth generation(5G)network and the gradual expansion of digital devices,harsh working environment for electronic devices has spawned higher requirements for microwave absorbing materials(MAMs).Since both the electromagnetic response and energy conversion character vary with temperature,to achieve temperature insensitive microwave absorption behaviour in wide temperature range has become extremely challenging.In this work,structured metacomposites containing sub-wavelength reduced graphene oxide(RGO)@carbon spheres were fabricated,and the microwave absorption was further improved through structural and composition design of the RGO@carbon units.Due to the unique anti-reflection effect on microwave of the metacomposites,the temperature-insensitive electromagnetic performance at elevated temperature could be exhibited.Moreover,both the dielectric relaxation behaviour and microwave absorption proformance of the system could be further increased.As a result,the effective absorption bandwidth(reflection loss(RL)<−10 dB)of the metacomposites with only 3.0 wt.%filler content could cover the entire X-band(8.2–12.4 GHz)frequency ranging from 298 to 473K.The metacomposite proposed in this work provides a“de-correlating”strategy to break the linkage between microwave absorption behaviour and temperature,which offers an interesting plateau for fabricating efficient high-temperature microwave absorption structures with tunable and designable advantages.展开更多
High-piezoelectric properties in lead-free materials have been the pursuit for both industry and scientific research.In this work,the synergistic approaches of phase/domain engineering and novel poling method are adop...High-piezoelectric properties in lead-free materials have been the pursuit for both industry and scientific research.In this work,the synergistic approaches of phase/domain engineering and novel poling method are adopted for the improvement of piezoelectric performance.The strategically designed lead-free donor-doped BiFeO_(3)-x BaTiO_(3) ceramics at the crystal structure morphotropic phase boundary(MPB)between the rhombohedral and tetragonal phases exhibited a high Curie temperature(T C≥450°C).Furthermore,si-multaneously enhanced static piezoelectric constant(d_(33))of 436±5 pC/N and thermally stable dynamic piezoelectric constant(d_(33)^(∗))of 550±10 pm/V were achieved.The high piezoelectric performance is col-lectively attributed to the crystal structure MPB,thermal quenching effect,local structure heterogeneity induced by donor doping,mesoscale nanodomains,and novel poling method inside a magnetic field.The temperature-insensitive and high piezoelectric performance of the current work is superior to the other lead-free piezoceramics.The synergistic approach for the improvement of piezoelectricity provides a path for the development of lead-free ceramics for high-temperature commercial applications.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No 11504320
文摘To obtain a stable amplified spontaneous emission（ASE） source for complex environment applications, we design an ASE source and study the output power and spectral characteristics under different ambient temperatures.We optimize the structure of the ASE source to flatten the ASE spectrum, and study the output characteristics in terms of output power and optical spectrum under different pump powers. Then the performance of the ASE source is investigated in the temperature range from-18.9°C to 50°C. A stable-power and flat-spectrum ASE source can be obtained by structural optimization and pump control.
基金financially supported by Zhejiang Provincial Natural Science Foundation of China(Nos.LQ20E020007,LQ19E020004 and LQ19E020005)the National Nature Science Foundation of China(Nos.51872069,52102230,52102165 and Y21E030023)+1 种基金the Teacher Professional Development Project for Domestic Visiting Scholars(No.FX2023015)the Fundamental Research Funds for the Provincial Universities of Zhejiang。
文摘Recently,application-oriented strain sensor has been intensively investigated in the fields of human motion detection,personalized health management and portable medical diagnosis.Despite significant efforts in improving its sensitivity and linear sensing range,developing the wearable strain sensor with stable signal remains a challenge.Herein,we proposed an ideal hybrid material with nearly zero temperature coefficient resistance(TCR)for temperature-insensitive strain sensing:the silver nanostructures(AgNTs)were introduced to coat the graphene foam(GrF)conformably by hydrothermal growth.The nanoscaled metal additives(TCR>0)not only endow GrF(TCR<0)with high electrical stability(TCR≈-0.3×10^(-3)℃^(-1)),but also offer the hybrid system additional structural elasticity,potential for next-generation of portable,stretchable and reliable devices.The resultant AgNTs@GrF hybrid material has been processed into a piezoresistive sensor with excellent sensing accuracy(strain error<2.7%),satisfactory gauge factor(GF)of227,wide sensing range up to 90%and good cyclic stability(>3000 cycles).Moreover,our strain sensor can be easily mounted on human skin as an epidermal device for reliable detection of electrophysiological stimuli,thus showing a great promising in practical wearable applications.
基金financial support provided by the National Natural Science Foundation of China(62374105,22179051,62304124,62204098)Special Fund of Taishan Scholar Program of Shandong Province(tsqnz20221141)+5 种基金Yunnan Provincial Science and Technology Project at Southwest United Graduate School(202302A0370009)the Key Applied Basic Research Program of Yunnan Province(202201AS070023)the Spring City Plan:the High-level Talent Promotion and Training Project of Kunming(2022SCP005)Project for Building a Science and Technology Innovation Center Facing South Asia and Southeast Asia(202403AP140015)Foundation of Key Laboratory of Advanced Technique&Preparation for Renewable Energy Materials,Ministry of Education,Yunnan Normal University(OF2022-01)Yunnan Revitalization Talent Support Program.
文摘Persistent operation inevitably elevates the temperature of perovskite solar cells(PSCs),posing a challenge for maximizing their power output and stability even after effective defect passivation and encapsulation techniques have been implemented.Regulating the thermal conductivity of halide perovskites by additive engineering is now a mainstream strategy for achieving self-cooling devices,but our fundamental understanding of how perovskites with atomic disorder function remains insufficient.This theoretical study unveils the underlying mechanism of facet-dependent thermodynamic properties in mixed-cation perovskites.The results demonstrate that the(100)facet has higher thermal conductivity than the(110)and(111)facets.By carefully controlling the(100)crystallographic orientation through buried and bulk modification,the thermal conductivity of the target perovskite film can be increased from 1.005 to 1.068 W m^(-1)K^(-1),which lowers the PSC's equilibrium temperature 5.25℃by accelerating heat transport and dissipation.Consequently,we achieve an inverted PSC with an excellent efficiency of 25.12%,accompanied by a significantly reduced temperature coefficient and better long-term stability:a conservation rate exceeding 90%after aging at 85℃and exposure to persistent light irradiation for 1100 h.This work elucidates a previously unidentified outcome of crystal facet engineering:the achievement of thermal management in high-performance PSCs.
基金supported by the National Key Research and Development Program of China(No.2024YFF0728500).
文摘Elastomer composites with stable electrical conductivity are crucial for the reliable operation of advanced flexible electronic devices under temperature variations or various deformations.However,current materials struggle to simultaneously maintain stable conductivity during significant thermal shocks or mechanical deformations.To address this challenge,we propose a general strategy for constructing temperature/deformation-insensitive conductive pathways by leveraging a liquid metal(LM)/polymer bicontinuous phase network.Based on the communicating vessellike structure of the material,the material enables selfadaptive interfacial void filling through solid–liquid cooperative deformation mechanisms,thereby maintaining conductive pathways under elevated temperatures or mechanical strains.At low temperatures,the LM undergoes expansion to establish new conductive channels,which reduces the material’s electrical resistance and ensures excellent conductivity in cryogenic environments.As a proof of concept,the elastomer exhibits exceptional and stable conductivity(σ298 K=500 S/cm)under drastic thermal shocks(ΔT=410 K).Furthermore,the material demonstrates minimal resistance variation under diverse deformations,with only a 1.2%increase in resistance under 170%tensile strain.Additionally,the composite maintains nearly invariant ultra-broadband electromagnetic shielding performance and stable thermal conductivity at elevated temperatures.This work provides a strategy for the design and fabrication of flexible conductive elastomers capable of stable operation in complex extreme environments.
基金the National Natural Science Foundation of China(Nos.U1704253 and 21671057).
文摘With the increasing advance of fifth generation(5G)network and the gradual expansion of digital devices,harsh working environment for electronic devices has spawned higher requirements for microwave absorbing materials(MAMs).Since both the electromagnetic response and energy conversion character vary with temperature,to achieve temperature insensitive microwave absorption behaviour in wide temperature range has become extremely challenging.In this work,structured metacomposites containing sub-wavelength reduced graphene oxide(RGO)@carbon spheres were fabricated,and the microwave absorption was further improved through structural and composition design of the RGO@carbon units.Due to the unique anti-reflection effect on microwave of the metacomposites,the temperature-insensitive electromagnetic performance at elevated temperature could be exhibited.Moreover,both the dielectric relaxation behaviour and microwave absorption proformance of the system could be further increased.As a result,the effective absorption bandwidth(reflection loss(RL)<−10 dB)of the metacomposites with only 3.0 wt.%filler content could cover the entire X-band(8.2–12.4 GHz)frequency ranging from 298 to 473K.The metacomposite proposed in this work provides a“de-correlating”strategy to break the linkage between microwave absorption behaviour and temperature,which offers an interesting plateau for fabricating efficient high-temperature microwave absorption structures with tunable and designable advantages.
基金the National Key Research and Development Program of China(Grant No.2022YFB3807404)the Special Funding Support for the Construction of Innovative Provinces in Hunan Province of China(Grant No.2020GK2062)Xuefan Zhou(Postdoc)is particularly grateful for the support from the China National Postdoctoral Program for Innovative Talents (Grant No. BX2021377 ).
文摘High-piezoelectric properties in lead-free materials have been the pursuit for both industry and scientific research.In this work,the synergistic approaches of phase/domain engineering and novel poling method are adopted for the improvement of piezoelectric performance.The strategically designed lead-free donor-doped BiFeO_(3)-x BaTiO_(3) ceramics at the crystal structure morphotropic phase boundary(MPB)between the rhombohedral and tetragonal phases exhibited a high Curie temperature(T C≥450°C).Furthermore,si-multaneously enhanced static piezoelectric constant(d_(33))of 436±5 pC/N and thermally stable dynamic piezoelectric constant(d_(33)^(∗))of 550±10 pm/V were achieved.The high piezoelectric performance is col-lectively attributed to the crystal structure MPB,thermal quenching effect,local structure heterogeneity induced by donor doping,mesoscale nanodomains,and novel poling method inside a magnetic field.The temperature-insensitive and high piezoelectric performance of the current work is superior to the other lead-free piezoceramics.The synergistic approach for the improvement of piezoelectricity provides a path for the development of lead-free ceramics for high-temperature commercial applications.
