AgNbO_(3)based antiferroelectric(AFE)ceramics have large maximum polarization and low remanent polarization,and thus are important candidates for fabricating dielectric capacitors.However,their energy storage performa...AgNbO_(3)based antiferroelectric(AFE)ceramics have large maximum polarization and low remanent polarization,and thus are important candidates for fabricating dielectric capacitors.However,their energy storage performances have been still large difference with those of lead-based AFEs because of their room-temperature ferrielectric(FIE)behavior.In this study,novel La^(3+)and Ta^(5+)co-substituted AgNbO_(3)ceramics are designed and developed.The introduction of La^(3+)and Ta^(5+)decreases the tolerance factor,reduces the polarizability of B-site cations and increases local structure heterogeneity of AgNbO_(3),which enhance AFE phase stability and refine polarization-electric field(PeE)loops.Besides,adding La^(3+)and Ta^(5+)into AgNbO_(3)ceramics causes the decrease of the grain sizes and the increase of the band gap,which contribute to increased Eb.As a consequence,a high recoverable energy density of 6.79 J/cm3 and large efficiency of 82.1%,which exceed those of many recently reported AgNbO_(3)based ceramics in terms of overall energy storage properties,are obtained in(Ag0.88La0.04)(Nb0.96Ta0.04)O_(3)ceramics.Furthermore,the discharge properties of the ceramic with discharge time of 16 ns and power density of 145.03 MW/cm3 outperform those of many lead-free dielectric ceramics.展开更多
Ferroelectric polymers are the mainstay of advanced flexible electronic devices.How to tailor the ferroelectric polymer films for various applications via simple processing approaches is challenging.Here we demonstrat...Ferroelectric polymers are the mainstay of advanced flexible electronic devices.How to tailor the ferroelectric polymer films for various applications via simple processing approaches is challenging.Here we demonstrate the tuning of ferroelectric responses can be achieved in polymer blends of poly(vinylidene fluoride-trifluoroethylene)(P(VDF-TrFE))and polymethyl methacrylate(PMMA)prepared via a simple two-step process.The proposed two-step process endows the polymer blends with a random distribution of P(VDF-TrFE)crystalline phase,hence decoupling the coherent ferroelectric domain interactions between continuous ordered crystalline phases that ubiquitously existed in common P(VDF-TrFE)film.The incorporation of the miscible non-crystalline PMMA chains with low-polarity results in reversal dipoles and a transition from ferroelectric to antiferroelectric-like behavior,overcoming the trade-off between the polarization and depolarization fields.In particular,resultant excellent mechanical and electrical properties of the polymer blend films give rise to remarkably improved breakdown strength and energy storage performance,surpassing P(VDF-TrFE)and commercial biaxial-oriented polypropylene films.This work provides a simple and effective strategy to tailor the ferroelectric response of polymeric materials with great potential for flexible electrical energy storage applications.展开更多
The need for ferroelectric materials with both narrow bandgaps(Eg)and large remanent polarization(Pr)remains a key challenge to the development of high-efficiency ferroelectric photovoltaic(FPV)devices.In this work,[(...The need for ferroelectric materials with both narrow bandgaps(Eg)and large remanent polarization(Pr)remains a key challenge to the development of high-efficiency ferroelectric photovoltaic(FPV)devices.In this work,[(K_(0.43)Na_(0.57))_(0.94)Li_(0.06)][(Nb_(0.94)Sb_(0.06))_(0.95)Ta_(0.05)]O_(3)(KNLNST)-based lead-free ceramics with narrow Eg and large P are obtained via Fe_(2)O_(3) doping.By optimizing the level of Fe_(2)O_(3) doping,a KNLNST+1.3%Fe_(2)O_(3) ceramic is fabricated that simultaneously possesses a narrow Eg of 1.74 eV and a large Pr of 27.05μC/cm^(2).These values are much superior to those of undoped KNLNST ceramics(Eg=3.1 eV and Pr=17.73μC/cm^(2)).While the large P stems from the increment of the volume ratio between the orthorhombic and tetragonal phases(Vo/VT)in KNLNST ceramics by proper amount of Fe3+doping,the narrow Eg is attributed to the coupling interaction between the Fe3+dopants and the B-site Sb3+host ions.Moreover,a switchable photovoltaic effect caused by the ferroelectric depolarization electric field(Edp)is observed in the KNLNST+1.3%Fe_(2)O_(3) ceramic-based device.Thanks to the narrower Eg and larger P,of the doped ceramic,the photovoltaic performance of the corresponding device(open-circuit voltage(Voc)=-5.28 V and short-circuit current density(JSC)=0.051μA/cm^(2))under a downward poling state is significantly superior to that of an undoped KNLNST-based device(Voc=-0.46 V and Jse=0.039μA/cm^(2)).This work offers a feasible approach to developing ferroelectric materials with narrow bandgaps and large Pr for photovoltaic applications.展开更多
基金supported by the National Key R&D Program of China(Grant No.2019YFB1503500)the National Natural Science Foundation of China(Grant Nos.51872079,52172113)+1 种基金the Natural Science Foundation of Hubei Province(Grant Nos.2019CFA006,2019CFA055)the Program for Science and Technology Innovation Team in Colleges of Hubei Province(T201901).
文摘AgNbO_(3)based antiferroelectric(AFE)ceramics have large maximum polarization and low remanent polarization,and thus are important candidates for fabricating dielectric capacitors.However,their energy storage performances have been still large difference with those of lead-based AFEs because of their room-temperature ferrielectric(FIE)behavior.In this study,novel La^(3+)and Ta^(5+)co-substituted AgNbO_(3)ceramics are designed and developed.The introduction of La^(3+)and Ta^(5+)decreases the tolerance factor,reduces the polarizability of B-site cations and increases local structure heterogeneity of AgNbO_(3),which enhance AFE phase stability and refine polarization-electric field(PeE)loops.Besides,adding La^(3+)and Ta^(5+)into AgNbO_(3)ceramics causes the decrease of the grain sizes and the increase of the band gap,which contribute to increased Eb.As a consequence,a high recoverable energy density of 6.79 J/cm3 and large efficiency of 82.1%,which exceed those of many recently reported AgNbO_(3)based ceramics in terms of overall energy storage properties,are obtained in(Ag0.88La0.04)(Nb0.96Ta0.04)O_(3)ceramics.Furthermore,the discharge properties of the ceramic with discharge time of 16 ns and power density of 145.03 MW/cm3 outperform those of many lead-free dielectric ceramics.
基金supported by the Basic Science Center Program of the National Natural Science Foundation of China(51788104)the National Natural Science Foundation of China(51802237,52072280,51872214 and 51872079)+2 种基金the Young Elite Scientists Sponsorship Program by CAST(2018QNRC001)the Open Fund of Hubei Key Laboratory of Ferro&Piezoelectric Materials and Devices(K201807)the Fundamental Research Funds for the Central Universities(193201002,183101005 and 182401004)。
文摘Ferroelectric polymers are the mainstay of advanced flexible electronic devices.How to tailor the ferroelectric polymer films for various applications via simple processing approaches is challenging.Here we demonstrate the tuning of ferroelectric responses can be achieved in polymer blends of poly(vinylidene fluoride-trifluoroethylene)(P(VDF-TrFE))and polymethyl methacrylate(PMMA)prepared via a simple two-step process.The proposed two-step process endows the polymer blends with a random distribution of P(VDF-TrFE)crystalline phase,hence decoupling the coherent ferroelectric domain interactions between continuous ordered crystalline phases that ubiquitously existed in common P(VDF-TrFE)film.The incorporation of the miscible non-crystalline PMMA chains with low-polarity results in reversal dipoles and a transition from ferroelectric to antiferroelectric-like behavior,overcoming the trade-off between the polarization and depolarization fields.In particular,resultant excellent mechanical and electrical properties of the polymer blend films give rise to remarkably improved breakdown strength and energy storage performance,surpassing P(VDF-TrFE)and commercial biaxial-oriented polypropylene films.This work provides a simple and effective strategy to tailor the ferroelectric response of polymeric materials with great potential for flexible electrical energy storage applications.
基金supported by the National Key R&D Program of China(Grant No.2019YFB1503500)the National Natural Science Foundation of China(Grant Nos.11975093,11774082,and 52202132)+3 种基金the Hubei Province Natural Science Foundation(Grant No.2019CFA006)the Program for Science and Technology Innovation Team in Colleges of Hubei Province(Grant No.T201901)the Hubei International Cooperation Project(Grant Nos.2021EHB005 and 2022EHB023)China Postdoctoral Science Foundation(Grant No.2021M701131).
文摘The need for ferroelectric materials with both narrow bandgaps(Eg)and large remanent polarization(Pr)remains a key challenge to the development of high-efficiency ferroelectric photovoltaic(FPV)devices.In this work,[(K_(0.43)Na_(0.57))_(0.94)Li_(0.06)][(Nb_(0.94)Sb_(0.06))_(0.95)Ta_(0.05)]O_(3)(KNLNST)-based lead-free ceramics with narrow Eg and large P are obtained via Fe_(2)O_(3) doping.By optimizing the level of Fe_(2)O_(3) doping,a KNLNST+1.3%Fe_(2)O_(3) ceramic is fabricated that simultaneously possesses a narrow Eg of 1.74 eV and a large Pr of 27.05μC/cm^(2).These values are much superior to those of undoped KNLNST ceramics(Eg=3.1 eV and Pr=17.73μC/cm^(2)).While the large P stems from the increment of the volume ratio between the orthorhombic and tetragonal phases(Vo/VT)in KNLNST ceramics by proper amount of Fe3+doping,the narrow Eg is attributed to the coupling interaction between the Fe3+dopants and the B-site Sb3+host ions.Moreover,a switchable photovoltaic effect caused by the ferroelectric depolarization electric field(Edp)is observed in the KNLNST+1.3%Fe_(2)O_(3) ceramic-based device.Thanks to the narrower Eg and larger P,of the doped ceramic,the photovoltaic performance of the corresponding device(open-circuit voltage(Voc)=-5.28 V and short-circuit current density(JSC)=0.051μA/cm^(2))under a downward poling state is significantly superior to that of an undoped KNLNST-based device(Voc=-0.46 V and Jse=0.039μA/cm^(2)).This work offers a feasible approach to developing ferroelectric materials with narrow bandgaps and large Pr for photovoltaic applications.
