XPS analyses have been performed to investigate the chemical conditions of Ni and oxygen on grain surfaces in single-sintered SrTiO3 capacitor-varistor ceramic doped with Nb2O5 and NiO. It is ascertained that Ni is in...XPS analyses have been performed to investigate the chemical conditions of Ni and oxygen on grain surfaces in single-sintered SrTiO3 capacitor-varistor ceramic doped with Nb2O5 and NiO. It is ascertained that Ni is in form of Ni2+ ions, which substitute for Ti4+ ions on grain surfaces during the oxidizing annealing. Moreover, it is confirmed that three kinds of chemically adsorbed oxygen such as O2-, O- and O-2(-) are formed on grain surfaces. It is proposed that these behaviors contribute greatly to the generation of multiple types of grain boundary acceptor states in the ceramic.展开更多
Against the backdrop of increasing miniaturization and integration of electronic components,the demand for materials with multifunctionality has increased significantly.Among these,transparent fluorescent ferroelectri...Against the backdrop of increasing miniaturization and integration of electronic components,the demand for materials with multifunctionality has increased significantly.Among these,transparent fluorescent ferroelectric ceramics exhibiting ferroelectricity,optical transparency,and photoluminescence(PL)have garnered significant attention.However,an interdependent relationship exists in a ferroelectric material among polarization,transparency,and photoluminescence,which presents a challenge for optimizing the coupling of optoelectronic properties.In this work,the doping concentration of Er^(3+ )in 0.825(K_(0.5)Na_(0.5))NbO_(3)-0.175Sr(Sc_(0.5)Nb_(0.5))O_(3):x%Er(x=0-0.15)system was modulated by first-principle calculations through compositional design and performance-influencing-factor-analysis strategies.The experimental results showed that grain size of the ceramic was reduced to 28 mm at x?0.05,concentration of vacancy defects in the lattice was low,and band gap value was increased to 3.105 eV.The multifunctional ceramic,while maintaining an excellent recoverable energy storage density(W_(rec)=2.03 J/cm^(3))and energy storage efficiency(η=75.67%),demonstrated a 56%(1100 nm)good nearinfrared transmittance and upconversion photoluminescence properties at 527,549 nm,and 667 nm exhibiting weak green,strong green,and weak red light,respectively.This study provides a theoretical foundation and new approach for realizing the multifunctionality of photoelectric couple by introducing rare earth elements as luminescent centers into ferroelectric ceramics.展开更多
With the rapid development of communication technology,multifunctional ceramics that integrate microwave dielectric and negative temperature coefficient(NTC)thermistor properties have met the evolving needs of electro...With the rapid development of communication technology,multifunctional ceramics that integrate microwave dielectric and negative temperature coefficient(NTC)thermistor properties have met the evolving needs of electronic components.Although conventional spinel oxides excel in single functionalities,they struggle to simultaneously achieve linear NTC behavior and stable microwave dielectric performance over a wide temperature range.To address this,the role of Sc^(3+)substitution in modifying Mg_(0.8)Mn_(0.2)Al_(1.6)Fe_(0.4)O_(4) ceramics was systematically investigated.The results demonstrate that Sc^(3+)substitution effectively inhibits oxygen vacancy formation and achieves the ratio regulation of the Mn^(2+)/Mn^(3+)and Fe^(3+)/Fe^(2+)bimetallic redox pairs,which significantly improves the material constant B(B_(200/1000℃)=8367-9758 K)and enables linear resistance-temperature curves(lnρ-1000/T)within a broad temperature range(200-1000℃).Additionally,the ceramics exhibit optimal microwave dielectric properties:low dielectric constants(ε_(r)=8.86-10.55),ultrahigh quality factors(Q∙f=96,000-149,000 GHz),and near-zero temperature coefficients of resonant frequency(τ_(f)=-33.2×10^(-6)to-10.2×10^(-6)℃^(-1)),resulting from Sc^(3+)-induced lattice stabilization and octahedral bond-valence strengthening effects.A cylindrical dielectric resonator antenna(CDRA)fabricated from Mg_(0.8)Mn_(0.2)Al_(1.3)Sc_(0.3)Fe_(0.4)O_(4) achieves 92%radiation efficiency and 6.28 dBi gain at 12 GHz,validating its potential for Ku-band satellite communication.This work reveals that Sc^(3+)substitution synergistically enhances both the microwave dielectric and thermosensitive functionalities of Mg-Al-Mn-Fe-O spinel ceramics,offering a breakthrough in material design for next-generation multifunctional communication devices.展开更多
It is a challenge to obtain highly tunable multifunctional performances in one ferroelectric system by a simple approach to meet the miniaturization,integration,and functionalization requirements of advanced electroni...It is a challenge to obtain highly tunable multifunctional performances in one ferroelectric system by a simple approach to meet the miniaturization,integration,and functionalization requirements of advanced electronic components.Herein,rare earth erbium(Er)modulated 0.9K_(0.5)Na_(0.5)NbO_(3)-0.1Sr(1-x)Er_(x)Ti_((1-x/4))O_(3),(0.9KNN-0.1ST:xEr)transparent-photoluminescent-ferroelectric energy storage multifunctional ceramics are prepared to solve this problem.The effect of lattice distortion and oxygen vacancies by Er doping on the optical and electrical properties is systematically investigated.The Er^(3+)ions can introduce a large distortion of the NbO_(6) octahedron by replacing the A-site in KNN-based ceramics.Thanks to the higher c/a ratio and lower oxygen vacancy content are simultaneously obtained in 0.9KNN-0.1ST:0.1Er ceramics.The effective energy storage density(Wrec)of 0.86 J/cm^(3),excellent near-infrared transmittance of 51.7%(1100 nm)and strong green upconversion photoluminescence are achieved in this multifunctional ceramic.This study provides a solid basis for rare earth ions doped ferroelectric ceramics with tunable multifunctional properties and has significant potential for applications in optoelectronic devices.展开更多
Rare earth-doped ferroelectric(FE)ceramics have attracted much attention due to their great potential application for novel multifunctional optical-electro devices.This study successfully devised and fabricated tungst...Rare earth-doped ferroelectric(FE)ceramics have attracted much attention due to their great potential application for novel multifunctional optical-electro devices.This study successfully devised and fabricated tungsten bronze Sr_(2-x)Sm_(x)Ag_(0.2)Na_(0.8)Nb_(5-x)Zr_(x)O_(15) ceramics,demonstrating exceptional energy storage and luminescent properties suitable for multifunctional capacitors.Effects of co-doping Sm^(3+) and Zr^(4+) in A and B sites on the phases structure,FE,energy storage and photoluminescence properties of Sr_(2-x)Sm_(x)Ag_(0.2)Na_(0.8)Nb_(5-x)Zr_(x)O_(15) ceramics were systematically investigated.Through employing various collaborative optimization strategies,encompassing the refinement of ceramic grains,the induction of nanodomain generation and the incorporation of large bandgap components,enhancement of breakdown strength and regulation of constructing relaxor FEs were achieved.Encouragingly,the high-performance multifunctional materials with remarkable recoverable energy storage metrics(Wee~3.72 J/cm,n~82.7%),brilliant red-orange light emission and distinguished frequency and temperature stabilities within specific ranges were obtained in Sr_(1.7)Sm_(0.3)Ag_(0.2)Na_(0.8)Nb_(4.7)Zr_(0.3)O_(15) ceramics.Besides,the multifunctional ceramics demonstrated a high-power density(68.1 MW/cm^(3)),a substantial current density(908.1 A/cm^(2))and a fast discharge time(51 ns)at 190kV/cm.These findings suggest that the designed Sr_(2-r)Sm_(x)Ag0.2Na0.8Nb_(5-x)Zr_(x)O_(15) ceramics hold promise as candidate materials for dielectric capacitors.展开更多
文摘XPS analyses have been performed to investigate the chemical conditions of Ni and oxygen on grain surfaces in single-sintered SrTiO3 capacitor-varistor ceramic doped with Nb2O5 and NiO. It is ascertained that Ni is in form of Ni2+ ions, which substitute for Ti4+ ions on grain surfaces during the oxidizing annealing. Moreover, it is confirmed that three kinds of chemically adsorbed oxygen such as O2-, O- and O-2(-) are formed on grain surfaces. It is proposed that these behaviors contribute greatly to the generation of multiple types of grain boundary acceptor states in the ceramic.
基金supported by the National Natural Science Foundation of China(Grant No.52002164,No.52060020,No.52162018,No.52162019)the Natural Science Foundation of Jiangxi Province of China(Grant No.20242BAB25224)+1 种基金The author from Institute of Materials Research and Engineering acknowledges supports from A*STAR,under RIE2020 AME Programmatic Fund(Grant No.A20G9b0135).supported by the High Performance Computing Service of the Modern Educational Technology and Information Center of Nanchang Hangkong University.
文摘Against the backdrop of increasing miniaturization and integration of electronic components,the demand for materials with multifunctionality has increased significantly.Among these,transparent fluorescent ferroelectric ceramics exhibiting ferroelectricity,optical transparency,and photoluminescence(PL)have garnered significant attention.However,an interdependent relationship exists in a ferroelectric material among polarization,transparency,and photoluminescence,which presents a challenge for optimizing the coupling of optoelectronic properties.In this work,the doping concentration of Er^(3+ )in 0.825(K_(0.5)Na_(0.5))NbO_(3)-0.175Sr(Sc_(0.5)Nb_(0.5))O_(3):x%Er(x=0-0.15)system was modulated by first-principle calculations through compositional design and performance-influencing-factor-analysis strategies.The experimental results showed that grain size of the ceramic was reduced to 28 mm at x?0.05,concentration of vacancy defects in the lattice was low,and band gap value was increased to 3.105 eV.The multifunctional ceramic,while maintaining an excellent recoverable energy storage density(W_(rec)=2.03 J/cm^(3))and energy storage efficiency(η=75.67%),demonstrated a 56%(1100 nm)good nearinfrared transmittance and upconversion photoluminescence properties at 527,549 nm,and 667 nm exhibiting weak green,strong green,and weak red light,respectively.This study provides a theoretical foundation and new approach for realizing the multifunctionality of photoelectric couple by introducing rare earth elements as luminescent centers into ferroelectric ceramics.
基金financial support from the Natural Science Foundation of Xinjiang Uygur Autonomous Region(No.2024D01E32)Xinjiang Tianshan Talent Training Program(No.2023TSYCCX0092)+1 种基金National Natural Science Foundation of China(No.62471468)Youth Innovation Promotion Association of CAS(No.Y2023117).
文摘With the rapid development of communication technology,multifunctional ceramics that integrate microwave dielectric and negative temperature coefficient(NTC)thermistor properties have met the evolving needs of electronic components.Although conventional spinel oxides excel in single functionalities,they struggle to simultaneously achieve linear NTC behavior and stable microwave dielectric performance over a wide temperature range.To address this,the role of Sc^(3+)substitution in modifying Mg_(0.8)Mn_(0.2)Al_(1.6)Fe_(0.4)O_(4) ceramics was systematically investigated.The results demonstrate that Sc^(3+)substitution effectively inhibits oxygen vacancy formation and achieves the ratio regulation of the Mn^(2+)/Mn^(3+)and Fe^(3+)/Fe^(2+)bimetallic redox pairs,which significantly improves the material constant B(B_(200/1000℃)=8367-9758 K)and enables linear resistance-temperature curves(lnρ-1000/T)within a broad temperature range(200-1000℃).Additionally,the ceramics exhibit optimal microwave dielectric properties:low dielectric constants(ε_(r)=8.86-10.55),ultrahigh quality factors(Q∙f=96,000-149,000 GHz),and near-zero temperature coefficients of resonant frequency(τ_(f)=-33.2×10^(-6)to-10.2×10^(-6)℃^(-1)),resulting from Sc^(3+)-induced lattice stabilization and octahedral bond-valence strengthening effects.A cylindrical dielectric resonator antenna(CDRA)fabricated from Mg_(0.8)Mn_(0.2)Al_(1.3)Sc_(0.3)Fe_(0.4)O_(4) achieves 92%radiation efficiency and 6.28 dBi gain at 12 GHz,validating its potential for Ku-band satellite communication.This work reveals that Sc^(3+)substitution synergistically enhances both the microwave dielectric and thermosensitive functionalities of Mg-Al-Mn-Fe-O spinel ceramics,offering a breakthrough in material design for next-generation multifunctional communication devices.
基金supported by the National Natural Science Foundation of China(Grants No.52162019,No.51802140,No.52202136,No.12174174)the Natural Science Foundation of Jiangxi Province(Grant No.20212ACB214011).L.S.expresses thanks for the support from Nanchang University.
文摘It is a challenge to obtain highly tunable multifunctional performances in one ferroelectric system by a simple approach to meet the miniaturization,integration,and functionalization requirements of advanced electronic components.Herein,rare earth erbium(Er)modulated 0.9K_(0.5)Na_(0.5)NbO_(3)-0.1Sr(1-x)Er_(x)Ti_((1-x/4))O_(3),(0.9KNN-0.1ST:xEr)transparent-photoluminescent-ferroelectric energy storage multifunctional ceramics are prepared to solve this problem.The effect of lattice distortion and oxygen vacancies by Er doping on the optical and electrical properties is systematically investigated.The Er^(3+)ions can introduce a large distortion of the NbO_(6) octahedron by replacing the A-site in KNN-based ceramics.Thanks to the higher c/a ratio and lower oxygen vacancy content are simultaneously obtained in 0.9KNN-0.1ST:0.1Er ceramics.The effective energy storage density(Wrec)of 0.86 J/cm^(3),excellent near-infrared transmittance of 51.7%(1100 nm)and strong green upconversion photoluminescence are achieved in this multifunctional ceramic.This study provides a solid basis for rare earth ions doped ferroelectric ceramics with tunable multifunctional properties and has significant potential for applications in optoelectronic devices.
基金supported by the National Science Foundation of China(Grant No.22475125)the Natural Science Basic Research Plan in the Shaanxi Province of China(Grant No.2024JC-YBMS-385)+2 种基金the Shaanxi Sanqin Scholars Innovation Team and the Young Talent Support Plan of Shaanxi Provincethe Fundamental Research Funds for the Central Universities(Program No.GK202002014)the Science and Technology Project of Xi'an,China(Grant No.2020KJRC0014).
文摘Rare earth-doped ferroelectric(FE)ceramics have attracted much attention due to their great potential application for novel multifunctional optical-electro devices.This study successfully devised and fabricated tungsten bronze Sr_(2-x)Sm_(x)Ag_(0.2)Na_(0.8)Nb_(5-x)Zr_(x)O_(15) ceramics,demonstrating exceptional energy storage and luminescent properties suitable for multifunctional capacitors.Effects of co-doping Sm^(3+) and Zr^(4+) in A and B sites on the phases structure,FE,energy storage and photoluminescence properties of Sr_(2-x)Sm_(x)Ag_(0.2)Na_(0.8)Nb_(5-x)Zr_(x)O_(15) ceramics were systematically investigated.Through employing various collaborative optimization strategies,encompassing the refinement of ceramic grains,the induction of nanodomain generation and the incorporation of large bandgap components,enhancement of breakdown strength and regulation of constructing relaxor FEs were achieved.Encouragingly,the high-performance multifunctional materials with remarkable recoverable energy storage metrics(Wee~3.72 J/cm,n~82.7%),brilliant red-orange light emission and distinguished frequency and temperature stabilities within specific ranges were obtained in Sr_(1.7)Sm_(0.3)Ag_(0.2)Na_(0.8)Nb_(4.7)Zr_(0.3)O_(15) ceramics.Besides,the multifunctional ceramics demonstrated a high-power density(68.1 MW/cm^(3)),a substantial current density(908.1 A/cm^(2))and a fast discharge time(51 ns)at 190kV/cm.These findings suggest that the designed Sr_(2-r)Sm_(x)Ag0.2Na0.8Nb_(5-x)Zr_(x)O_(15) ceramics hold promise as candidate materials for dielectric capacitors.
