The electrocaloric effect(ECE)offers a pathway to environmentally sustainable and easily miniaturized refrigeration technology,positioning it as a front-runner for the next generation of solid-state cooling solutions....The electrocaloric effect(ECE)offers a pathway to environmentally sustainable and easily miniaturized refrigeration technology,positioning it as a front-runner for the next generation of solid-state cooling solutions.This research unveils a remarkable ECE in afinely tuned(Ba_(0.86)Ca_(0.14))_(0.98)La_(0.02)Ti_(0.92)Sn_(0.08)O_(3)ceramic,exhibiting a temperature shift(DT)of 1.6 K across more than 85%of the maximumΔT(ΔT_(max))and spanning an exceptionally wide operational range of 92 K.Our investigation on dielectric responses and ferroelectric polarization-electricfield(PeE)loops suggests that the broad operational scope results from the fragmentation of extended ferroelectric domains into smaller domains and polar nano-regions(PNRs)supported by PFM analysis.Furthermore,the introduction of La enhances spontaneous polarization by significantly extending the maximum electricfield that can be applied,facilitating highperformance ECE at ambient temperature.This study positions BaTiO_(3)-based lead-free ceramic as a sustainable alternative for addressing the cooling demands of modern electronic components,marking a significant stride toward next-generation solid-state refrigeration.展开更多
Ferroelectric materials are highly promising for next-generation electro-optic(EO)modulators because of their ultrafast and efficient light modulation.However,efforts to maximize polarization freedom for large refract...Ferroelectric materials are highly promising for next-generation electro-optic(EO)modulators because of their ultrafast and efficient light modulation.However,efforts to maximize polarization freedom for large refractive index modulation—through domain engineering,epitaxial strain,and defect engineering—have hit limitations,leaving intrinsic polarization mechanisms largely unexplored.Here,we report a giant effective EO coefficient(~233.5 pm/V)in PbZr_(0.52)Ti_(0.48)O_(3)(PZT)films,which surpasses all reported values measured under an in-plane electric field and significantly exceeds the theoretical limit(~13 pm/V)as well as the value of LiNbO_(3)(~31 pm/V).Beyond conventional domain switching,phase transitions and domain wall variations critically enhance the EO effect.The highly relaxed structure of the PZT film,with mixed[001]and[100]orientations and disordered nanoscale phases,enables unprecedented polarization control.This unique configuration breaks the theoretical EO coefficient limit,bridging the gap between predictions and experimental results.Owing to its high Curie temperature and compatibility with wafer-scale fabrication,PZT has emerged as a promising candidate for next-generation high-performance EO modulators.Our findings not only advance the frontiers of ferroelectric EO materials but also pave the way for exploring other ferroelectric thin-film devices,such as those for energy storage and electrocaloric cooling,by leveraging enhanced polarization modulation mechanisms.展开更多
Simultaneously employing light and vibration energy by piezoelectric material to realize environmental remediation is an advanced oxidation method.Silver niobate(AgNbO_(3))is a visible light driven photocatalyst for t...Simultaneously employing light and vibration energy by piezoelectric material to realize environmental remediation is an advanced oxidation method.Silver niobate(AgNbO_(3))is a visible light driven photocatalyst for the removal of organic pollutants.However,the high recombination rate of photo-generated electrons and holes suppresses its photocatalytic activity.Piezoelectric potential excited by vibration can facilitate the separation of light induced charges.Unfortunately,AgNbO_(3) is an antiferroelectric.In this work,distinct photo-/vibration-bi-catalysis has been achieved in ferroelectric(1−x)AgNbO_(3)-xLiTaO_(3) solid solution.The results show that ~96% Rhodamine B(RhB)can be decomposed under the bi-excitation of ultrasound and visible light within 120 min with 0.95AgNbO_(3)-0.05LiTaO_(3) catalyst.The synergy effect from efficient visible light excitation and enhanced separation of the photo-induced charges from the electric field by the mechanical strain results in the distinct decomposition performance of catalysts.展开更多
Ferroelectric thin/thick films with large electrocaloric(EC)effect are critical for solid state cooling technologies.Here,large positive EC effects with two EC peaks in a broad temperature range(~100 K)were obtained i...Ferroelectric thin/thick films with large electrocaloric(EC)effect are critical for solid state cooling technologies.Here,large positive EC effects with two EC peaks in a broad temperature range(~100 K)were obtained in 0.95Pb_(0.92)La_(0.08)(Zr_(0.70)Ti_(0.30))_(0.98)O_(3)-0.05BiFeO_(3)(BFO-La-codoped PZT)epitaxial thin films deposited on the(100),(110)and(111)oriented SrTiO_(3)(STO)substrates by a sol-gel method.The thin film deposited on the(111)oriented STO substrate exhibited a stronger EC effect(~20.6 K at 1956 kV/cm)near room temperature.However,the thin films deposited on the(100)and(110)oriented STO substrates exhibited a stronger EC effect(~18.8 K at 1852 kV/cm and~20.8 K at 1230 kV/cm,respectively)around the peak of the dielectric permittivity(T_(m),~375 K).Particularly,as the direction of the applied electric field was switched(E<0),the DT of the(100)-oriented thin films around T_(m) was enhanced significantly from 18.8 K to 38.1 K.The self-induced-poling during the preparing process maybe plays a key role on the magic phenomenon.It can be concluded that the BFO-La-codoped PZT epitaxial thin films are promising candidates for application in the next solid-state cooling devices.展开更多
In this study,a micro in-plane p-type thermoelectric generator(TEG),which consists of thin-film Si_(1-x-y)Ge_(x)Sn_(y) ternary alloy semiconductor on insulator,is developed to make efficient use of waste heat such as ...In this study,a micro in-plane p-type thermoelectric generator(TEG),which consists of thin-film Si_(1-x-y)Ge_(x)Sn_(y) ternary alloy semiconductor on insulator,is developed to make efficient use of waste heat such as human body.A power factor value as high as 1095 mWm^(-1) K^(-2) had been achieved using Bion implanted and short-term rapid thermal annealing(RTA)process.In addition,a measuring scheme for micro TEG without external load resistance was designed.In one measuring session,multiple parameters can be measured.The micro single-arm TEG prepared by semiconductor process can output 0.29 nW power at a temperature difference of 15 K,and a cross-sectional power density has reached up to 0.58 mW/cm^(2),which is a superior value for wearable device.The findings of this study have important reference value for wearable device performance improvement and output power measuring of micro TEG.展开更多
Tunable devices constructed by ferroelectric thin flms are often desired to possess a low dielectric loss while maintainging a high dielectric tunability over a broad operating temperature range in applications,for ex...Tunable devices constructed by ferroelectric thin flms are often desired to possess a low dielectric loss while maintainging a high dielectric tunability over a broad operating temperature range in applications,for example,resonators,filters,or phase shifters.However,it is dificult to simultaneously achieve these characteristics by traditional strategies,such as doping and strain modifying.Here,we demonstrate that the dielectric tunability of the sol-gel-prepared Pb(Sc_(1/2)Nb_(1/2))_(0.9)(Mg_(1/3)Nb_(2/3))_(0.O3)(PSNMN)thin film can be almost doubled from~47%to~80.0%(at 10kHz)at a low electric field(~530kV/cm),and the dielectric loss can be sharply reduced by more than an order of magnitude,from~0.50 to~0.037(at 1 kHz)when the thin flm was annealed in air at 650℃ for 15h under the help of an atmosphere-compensating-block(ACB)made from the proto-PSNMN gel.Moreover,the PSNMN thin flm annealed with ACB also exhibited an extremely high thermally-stable dielectric tunability in an ultrabroad temperature range(>130 K),which could be attributed to the Maxwell-Wagner(MW)effect generated by the interface between the PSNMN disordered matrix and the B-site nanoscale-ordered structure formed during the long-term annealing process.The reduced dielectric loss is mainly benefited from the reduced concentration of oxygen vacancy and the possibie MW efects,and the enhanced dielectric tunability could be ascribed to the weaker domain-pinning effect by oxygen vacancy.The breakthrough provides a new universal strategy to achieve utrahigh tunable performance in A(B'_(1/2)B"_(1/2))O3 ferroelectric thin films with a B-site nanoscale-ordered structure,meanwhile it paves the way for ultraintergrated tunable thin-flm-devices with great phase shifter performance in practical applications.展开更多
基金the Science and Technology Plan of Guangxi(Nos.AA23023027,AB24010230)the Key Research and Development Program of Shandong Province(2022CXGC020203)+1 种基金the Natural Science Foundation of China(Grant No.12264012,62271362,12304120)the Science and Technology Plan of Guilin(2022H03 and ZY20220101).
文摘The electrocaloric effect(ECE)offers a pathway to environmentally sustainable and easily miniaturized refrigeration technology,positioning it as a front-runner for the next generation of solid-state cooling solutions.This research unveils a remarkable ECE in afinely tuned(Ba_(0.86)Ca_(0.14))_(0.98)La_(0.02)Ti_(0.92)Sn_(0.08)O_(3)ceramic,exhibiting a temperature shift(DT)of 1.6 K across more than 85%of the maximumΔT(ΔT_(max))and spanning an exceptionally wide operational range of 92 K.Our investigation on dielectric responses and ferroelectric polarization-electricfield(PeE)loops suggests that the broad operational scope results from the fragmentation of extended ferroelectric domains into smaller domains and polar nano-regions(PNRs)supported by PFM analysis.Furthermore,the introduction of La enhances spontaneous polarization by significantly extending the maximum electricfield that can be applied,facilitating highperformance ECE at ambient temperature.This study positions BaTiO_(3)-based lead-free ceramic as a sustainable alternative for addressing the cooling demands of modern electronic components,marking a significant stride toward next-generation solid-state refrigeration.
基金Wen Dong acknowledges National Key R&D Program of China(No.2024YFA1409703)National Natural Science Foundation of China(No.52202134)+4 种基金Hubei Nature Science Foundation(No.2022CFB595)Biaolin Peng acknowledges the Key Research and Development Program of Shandong Province of China(No.2022CXGC020203)National Natural Science Foundation of China(No.62271362)Shenglin Jiang acknowledges National Natural Science Foundation of China(No.61971459)the Analytical and Testing Center of Huazhong University of Science and Technology,Electron Microscopy Center of Yunnan University(No.2022CFB595).
文摘Ferroelectric materials are highly promising for next-generation electro-optic(EO)modulators because of their ultrafast and efficient light modulation.However,efforts to maximize polarization freedom for large refractive index modulation—through domain engineering,epitaxial strain,and defect engineering—have hit limitations,leaving intrinsic polarization mechanisms largely unexplored.Here,we report a giant effective EO coefficient(~233.5 pm/V)in PbZr_(0.52)Ti_(0.48)O_(3)(PZT)films,which surpasses all reported values measured under an in-plane electric field and significantly exceeds the theoretical limit(~13 pm/V)as well as the value of LiNbO_(3)(~31 pm/V).Beyond conventional domain switching,phase transitions and domain wall variations critically enhance the EO effect.The highly relaxed structure of the PZT film,with mixed[001]and[100]orientations and disordered nanoscale phases,enables unprecedented polarization control.This unique configuration breaks the theoretical EO coefficient limit,bridging the gap between predictions and experimental results.Owing to its high Curie temperature and compatibility with wafer-scale fabrication,PZT has emerged as a promising candidate for next-generation high-performance EO modulators.Our findings not only advance the frontiers of ferroelectric EO materials but also pave the way for exploring other ferroelectric thin-film devices,such as those for energy storage and electrocaloric cooling,by leveraging enhanced polarization modulation mechanisms.
基金supported by the National Natural Science Foundation of China(Nos.51562029 and 21762031)Program for Grassland Elite of Inner Mongolia Autonomous Region(No.CYYC10032)Program for Innovative Research Team in Universities of Inner Mongolia Autonomous Region(No.NMGIRT2214).
文摘Simultaneously employing light and vibration energy by piezoelectric material to realize environmental remediation is an advanced oxidation method.Silver niobate(AgNbO_(3))is a visible light driven photocatalyst for the removal of organic pollutants.However,the high recombination rate of photo-generated electrons and holes suppresses its photocatalytic activity.Piezoelectric potential excited by vibration can facilitate the separation of light induced charges.Unfortunately,AgNbO_(3) is an antiferroelectric.In this work,distinct photo-/vibration-bi-catalysis has been achieved in ferroelectric(1−x)AgNbO_(3)-xLiTaO_(3) solid solution.The results show that ~96% Rhodamine B(RhB)can be decomposed under the bi-excitation of ultrasound and visible light within 120 min with 0.95AgNbO_(3)-0.05LiTaO_(3) catalyst.The synergy effect from efficient visible light excitation and enhanced separation of the photo-induced charges from the electric field by the mechanical strain results in the distinct decomposition performance of catalysts.
基金supported by the National Natural Science Foundation of China(51402196,51973170)the Innovation Project of Guangxi Graduate Education(YCSW2020047)+3 种基金the Guangxi Natural Science Foundation(2017GXNSFFA198015)the open Foundation of Guangxi Key Laboratory of Optical and Electronic Materials and Devices(20KF-6)the Natural Science Foundation of Shaanxi Province(Grant No.2019JCW-17,2020JCW-15)the Development and Planning Guide Foundation of Xidian University(Grant No.21103200005).
文摘Ferroelectric thin/thick films with large electrocaloric(EC)effect are critical for solid state cooling technologies.Here,large positive EC effects with two EC peaks in a broad temperature range(~100 K)were obtained in 0.95Pb_(0.92)La_(0.08)(Zr_(0.70)Ti_(0.30))_(0.98)O_(3)-0.05BiFeO_(3)(BFO-La-codoped PZT)epitaxial thin films deposited on the(100),(110)and(111)oriented SrTiO_(3)(STO)substrates by a sol-gel method.The thin film deposited on the(111)oriented STO substrate exhibited a stronger EC effect(~20.6 K at 1956 kV/cm)near room temperature.However,the thin films deposited on the(100)and(110)oriented STO substrates exhibited a stronger EC effect(~18.8 K at 1852 kV/cm and~20.8 K at 1230 kV/cm,respectively)around the peak of the dielectric permittivity(T_(m),~375 K).Particularly,as the direction of the applied electric field was switched(E<0),the DT of the(100)-oriented thin films around T_(m) was enhanced significantly from 18.8 K to 38.1 K.The self-induced-poling during the preparing process maybe plays a key role on the magic phenomenon.It can be concluded that the BFO-La-codoped PZT epitaxial thin films are promising candidates for application in the next solid-state cooling devices.
基金supported by PRESTO(Grant No.JPMJPR15R2)and CREST(Grant No.JPMJCR19Q5)from the JST in Japan,a research grant(Creation of Life Innovation Materials for Interdisciplinary and International Researcher Development)from the MEXT in Japan,the National Natural Science Foundation of China(Grant Nos.51772056,51961011,52061009)+2 种基金National Key Research and Development Program of China(No.2017YFE0198000)Guangxi Natural Science Foundation of China(Grant No.2019GXNSFAA245039,2017 GXNSFFA198015)the open foundation of Guangxi Key laboratory of Processing for Nonferrous Metals and Featured Materials,Guangxi University(Grant No.2020GXYSOF11).
文摘In this study,a micro in-plane p-type thermoelectric generator(TEG),which consists of thin-film Si_(1-x-y)Ge_(x)Sn_(y) ternary alloy semiconductor on insulator,is developed to make efficient use of waste heat such as human body.A power factor value as high as 1095 mWm^(-1) K^(-2) had been achieved using Bion implanted and short-term rapid thermal annealing(RTA)process.In addition,a measuring scheme for micro TEG without external load resistance was designed.In one measuring session,multiple parameters can be measured.The micro single-arm TEG prepared by semiconductor process can output 0.29 nW power at a temperature difference of 15 K,and a cross-sectional power density has reached up to 0.58 mW/cm^(2),which is a superior value for wearable device.The findings of this study have important reference value for wearable device performance improvement and output power measuring of micro TEG.
基金supported by the National Natural Science Foundation of China(51402196,52072218,52192613)the National Key Research and Development Program of China(2021YFB3601504)the Natural Science Foundation of Shandong Province(ZR2022YQ43).
文摘Tunable devices constructed by ferroelectric thin flms are often desired to possess a low dielectric loss while maintainging a high dielectric tunability over a broad operating temperature range in applications,for example,resonators,filters,or phase shifters.However,it is dificult to simultaneously achieve these characteristics by traditional strategies,such as doping and strain modifying.Here,we demonstrate that the dielectric tunability of the sol-gel-prepared Pb(Sc_(1/2)Nb_(1/2))_(0.9)(Mg_(1/3)Nb_(2/3))_(0.O3)(PSNMN)thin film can be almost doubled from~47%to~80.0%(at 10kHz)at a low electric field(~530kV/cm),and the dielectric loss can be sharply reduced by more than an order of magnitude,from~0.50 to~0.037(at 1 kHz)when the thin flm was annealed in air at 650℃ for 15h under the help of an atmosphere-compensating-block(ACB)made from the proto-PSNMN gel.Moreover,the PSNMN thin flm annealed with ACB also exhibited an extremely high thermally-stable dielectric tunability in an ultrabroad temperature range(>130 K),which could be attributed to the Maxwell-Wagner(MW)effect generated by the interface between the PSNMN disordered matrix and the B-site nanoscale-ordered structure formed during the long-term annealing process.The reduced dielectric loss is mainly benefited from the reduced concentration of oxygen vacancy and the possibie MW efects,and the enhanced dielectric tunability could be ascribed to the weaker domain-pinning effect by oxygen vacancy.The breakthrough provides a new universal strategy to achieve utrahigh tunable performance in A(B'_(1/2)B"_(1/2))O3 ferroelectric thin films with a B-site nanoscale-ordered structure,meanwhile it paves the way for ultraintergrated tunable thin-flm-devices with great phase shifter performance in practical applications.
