Europium and terbium coordination polymers of pyridine-3-carboxylic acid were in-situ composed with ethyt methacrylate （ EMA ）. With the polymerization of EMA monomer and the formation of europium and terbium coordi...Europium and terbium coordination polymers of pyridine-3-carboxylic acid were in-situ composed with ethyt methacrylate （ EMA ）. With the polymerization of EMA monomer and the formation of europium and terbium coordination polymers of pyridiae- 3-carboxylic acid, the transparent hybrid thick fihns composed of [ Eu（ NIC ）3 ]n （ [ Tb（ NIC）3 ]n ） and poly ethyl mettuwrylate （ PEMA ） have been prepared. The luminescence properties and energy transfer of these polymeric composites were studied with absorption spectra, fluorescent excitation trod emission spectra in detail. All the hybrid thick films composed of terbium coordination polymer show the characteristic strong green emission of terbium ions, which implies the same energy transfer mechanism as the pure complex and the hybrid composite film is a suitable sabstrate for the luminescence of terbium ions. In the range of camposing concentration of luminescent species （0.01,0.025,0.05,0.1 mmol /15 mL EMA ）, emission intensities increase with the increasing of corresponding composing concentration and the concentration quenching effect does not take place.展开更多
Er^(3+)-doped Ba_(0.85)Ca_(0.15)Ti_(0.9)Zr_(0.1O3)(xEr-BCTZ,x=0,0.005,0.01,0.015)multifunctional thick films were prepared by the tape-casting method,using sol-gel-derived nano-sized powders as the matrix material.The...Er^(3+)-doped Ba_(0.85)Ca_(0.15)Ti_(0.9)Zr_(0.1O3)(xEr-BCTZ,x=0,0.005,0.01,0.015)multifunctional thick films were prepared by the tape-casting method,using sol-gel-derived nano-sized powders as the matrix material.The surface morphologies,photoluminescence,and electrical properties were investigated.Dense microstructures with pure perovskite structure were obtained in the thick films.By doping an appropriate amount of Er^(3+),the samples exhibit superior up-conversion photoluminescence performance and simultaneously enhanced electrical performances.In addition,relatively higher texture fractions(with the largest value of 83.5%)were realized through introducing plate-like BaTiO_(3) templates to make the thick film grow by the[001]_(c) orientation.And the ferro-/piezoelectric properties of the thick films were further improved,showing potential in the applications of micro-optoelectronic devices.展开更多
The preparation and properties of thick flexible three-phase composite films based on lead zirconium titanate(PZT) and various ferrites(nickel zinc ferrite(NZF) and cobalt ferrite(CF)) were reported in this study. Pro...The preparation and properties of thick flexible three-phase composite films based on lead zirconium titanate(PZT) and various ferrites(nickel zinc ferrite(NZF) and cobalt ferrite(CF)) were reported in this study. Properties of three-phase composite films were compared with pure polyvinylidene fluoride(PVDF) and PZT–PVDF films. X-ray diffraction data indicated the formation of well crystallized structure of PZT and NZF/CF phases, without the presence of undesirable phases. Scanning electron micrographs showed that the ceramic particles were dispersed homogeneously in the PVDF matrix and atomic force microscopy confirmed that the size of the particles is around 30 nm. Non-saturated hysteresis loops were evident in all samples due to the presence of highly conductive ferrite phases. Under magnetic field of 10 k Oe, composite films exhibited a typical ferromagnetic response. Dielectric properties were investigated in the temperature range from –128 to 250 ℃ and frequency range of 400 Hz–1 MHz. The results showed that the value of dielectric constant of the PVDF/PZT/ferrite composites increased about 25% above the one obtained for pure PVDF.展开更多
The BiFeO3-based film is one of the most promising candidates for lead-free piezoelectric film devices.In this work,the 1μm-thick Bi(Fe_(0.93)Mn_(0.05)Ti_(0.02))O_(3)(BFMT)films are grown on the ITO/glass substrate u...The BiFeO3-based film is one of the most promising candidates for lead-free piezoelectric film devices.In this work,the 1μm-thick Bi(Fe_(0.93)Mn_(0.05)Ti_(0.02))O_(3)(BFMT)films are grown on the ITO/glass substrate using a sol-gel method combined with spin-coating and layer-by-layer annealing technique.These films display a large saturated polarization of 95μC/cm^(2),and a remanent polarization of 70μC/cm^(2).Especially,the films are self-poled caused by an internal bias field,giving rise to asymmetric polarization-electric field(P-E)loops with a positive shift along the x-axis.A stable self-polarization state is maintained during the applied electric field increasing to 1500 kV/cm and then decreasing back.The weak dependence of P-E loops on frequency(1-50 kHz)and temperature(25-125°C)indicate that the internal bias field can be stable within a certain frequency and temperature range.These results demonstrate that the self-polarized BFMT thick films can be integrated into devices without any poling process,with promising applications in micro-electro-mechanical systems.展开更多
Er ions are implanted into the GaN thick films grown by hydride vapor phase epitaxy. The implantation energy is 200 keV and the implantation doses are 1 × 10^13, 1 × 10^14, 1 × 10^15, and 5 × 10^15...Er ions are implanted into the GaN thick films grown by hydride vapor phase epitaxy. The implantation energy is 200 keV and the implantation doses are 1 × 10^13, 1 × 10^14, 1 × 10^15, and 5 × 10^15 atom/cm2, respectively. The effects of the implantation dose and annealing temperature on the GaN band-edge luminescence are investigated. The cathodoluminescence spectra from 82 to 323 K are measured for 1 × 10^15 atom/cm2- implanted GaN annealed at 1100℃. Luminescence peaks at 356, 362, 376, 390, and 414 nm are observed on the 82 K cathodoluminescence spectrum. When the temperature is increased to 150 K, the intensities of the 356 and 414 nm peaks are nearly unchanged and the 362,376, and 390 nm peaks disappear. The intensity ratio of 538 nm （2H11/2 →4 4I15/2） and 559 nm （4A3/2 →4I15/2） is increased with the increase in temperature. We try to shed light on the above interesting phenomena.展开更多
SiO_2/TiO_2/methylcellulose composite materials processed by the sol-gel technique were studied for optical waveguide applications. With the help of methylcellulose, an organic binder, SiO2/TiO2/methylcellulose hybrid...SiO_2/TiO_2/methylcellulose composite materials processed by the sol-gel technique were studied for optical waveguide applications. With the help of methylcellulose, an organic binder, SiO2/TiO2/methylcellulose hybrid thick films were prepared by a single spin-coating processes. After annealing at 70 °C for an hour, 2.5-μm crack-free and dense organic-inorganic hybrid optical films with a refractive index of 1.537 were achieved. Optical losses of plane waveguide made up of those films and ordinary slide glass substrate are around 0.3 dB/cm at 650 nm. Scanning electronmicroscopy (SEM) and UV-visible spectroscopy (UV-VIS), have been used to characterize the thick films.展开更多
50μm-thick(Pb_(0.9)7La_(0.02))(Zr_(0.92)Sn_(0.05)Ti_(0.03))O_(3) antiferroelectric(AFE)thick films with different amount of 0.8Pb_O-0.2B_(2)O_(3) glass additions were fabricated by the screen-printing method on alumi...50μm-thick(Pb_(0.9)7La_(0.02))(Zr_(0.92)Sn_(0.05)Ti_(0.03))O_(3) antiferroelectric(AFE)thick films with different amount of 0.8Pb_O-0.2B_(2)O_(3) glass additions were fabricated by the screen-printing method on alumina substrate,which was pre-coated with Pt as electrode.The effects of glass additions on dielectric properties and energy storage performance were investigated in details.Due to the enhancement of breakdown strength(BDS)of the specimens by the addition of glass,the energy storage performances of the thick films could be greatly improved.As a result,with 3%glass addition,the BDS of the specimens were as high as 475 kV/cm,the maximum polarization of 34.8μC/cm^(2) and the maximum recoverable energy storage density of 7.4 J/cm^(3) were obtained.The results indicated the(Pb_(0.9)7La_(0.02))(Zr_(0.92)Sn_(0.05)Ti_(0.03))O_(3) (PLZST)thick films have a promising potential application in capacitors for pulsed power systems.展开更多
Thick-film thermistor with negative temperature coefficient（NTC）, low room-temperature resistivity and modest thermistor constant was screen-printed on the alumina substrate by the combination of 30.94III0.04II0.02 ...Thick-film thermistor with negative temperature coefficient（NTC）, low room-temperature resistivity and modest thermistor constant was screen-printed on the alumina substrate by the combination of 30.94III0.04II0.02 B OBi Coa Co with Ba0.5Bi0.5Fe0.9Sn0.1O3. The electrical properties of the thick films were characterized by a digital multimeter, a Keithley 2400 and an impedance analyzer. The results show that with the Ba0.5Bi0.5Fe0.9Sn0.1O3 content increasing from 0.05 to 0.25, the values of room-temperature resistivity, thermistor constant and peak voltage of the thick films increases and are in the ranges of 1.47-26.5 ？·cm, 678-1345 K and 18.9-47.0 V, respectively. The corresponding current at the peak voltage of the thick films decreases and is in the range of 40-240 m A. The impedance spectroscopy measurement demonstrates that the as-prepared thick films show the abnormal electrical heterogeneous microstructure, consisting of high-resistive grains and less resistive grain boundary regions. It can be concluded that the addition of Ba0.5Bi0.5Fe0.9Sn0.1O3 into 30.94III0.04II0.02 Ba Co OBi Co improves the thermistor behavior and but also deteriorates the current characteristics.展开更多
In this paper, the oriented M-type barium ferrite （BaM） thick films with different thicknesses are prepared by tape casting. It is found that the crystallographic alignment degree （f）, the pore and the squareness ...In this paper, the oriented M-type barium ferrite （BaM） thick films with different thicknesses are prepared by tape casting. It is found that the crystallographic alignment degree （f）, the pore and the squareness ratio （Mr/Ms） are not affected by the thickness of the film. XRD and SEM results show that the thick film has hexagonal morphology with a crystal texture of c-axis grains perpendicular to film plane. The hysteresis curve indicates that the BaM thick film exhibits a self-biased property with a remanent magnetization of 3.30 T, a squareness ratio （Mr/Ms） of 0.81, and a coercivity of 0.40 T. The results show that the BaM thick film has potential for use in self-biasing microwave devices, and also proves that the tape casting technique is capable of fabricating high-quality barium ferrite films, thus providing a unique opportunity to realize the large area production of thick film.展开更多
Room-temperature fabrication of functional ceramic films using powder aerosol deposition(AD)is important for practical applications.However,the as-processed ferroelectric films show unusual temperature-dependent diele...Room-temperature fabrication of functional ceramic films using powder aerosol deposition(AD)is important for practical applications.However,the as-processed ferroelectric films show unusual temperature-dependent dielectric response,including enhanced conductivity in the as-processed state and subsequent significant increase in the permittivity following heat treatment.In this work,we investigate the influence of the residual internal stresses developed during the high-impact consolidation process on the dielectric response.Moreover,the recombination of charged defects generated during deposition is driven by the temperature and the atmospheric condition during the heat treatment as well as the carrier gas type used during deposition.Thermal treatment up to 500℃ in different atmospheres was used to tune the dielectric and ferroelectric response,highlighting that irrespective of the type of carrier gas,AD deposition process induces charged defects in polar oxide ceramics that can be reduced through heat-treatment far-below their bulk sintering temperature.Macroscopic electromechanical properties are contrasted to in-situ heating scanning transmission electron microscopy to observe possible local effects,such as crystallization,grain growth,crystal defect structure,or grain reorientation.In addition X-ray diffraction and X-ray photoelectron spectroscopy studies were conducted to gain insight into the effect of annealing on the crystal structure and local moisture adsorption.展开更多
A true single-step process suitable for fabrication of micro-periodic structure in polymer films by twophoton initiated photopolymerization and laser ablation is presented. By the right choice of the irradiation energ...A true single-step process suitable for fabrication of micro-periodic structure in polymer films by twophoton initiated photopolymerization and laser ablation is presented. By the right choice of the irradiation energy, the irradiated zone is modified or ablated in the 1.44-μm-thick film. The mechanism of grating generation and the potential application of the gratings in integrated optics are discussed.展开更多
Intrinsic zinc oxide films, normally deposited by radio frequency （RF） sputtering, are fabricated by direct current （DC） sputtering. The oxygen-deficient targets are prepared via a newly developed double crucible ...Intrinsic zinc oxide films, normally deposited by radio frequency （RF） sputtering, are fabricated by direct current （DC） sputtering. The oxygen-deficient targets are prepared via a newly developed double crucible method. The 800-nm-thick film obtaines significantly higher carrier mobility compareing with that of the 800-nm-thick ZnO film. This is achieved by the widely used RF sputtering, which favors the prevention of carrier recombination at the interfaces and reduction of the series resistance of solar cells. The optimal ZnO film is used in a Cu （ln, Ga） Se2 （CIGS） solar cell with a high efficiency of 11.57%. This letter demonstrates that the insulating ZnO films can be deposited by DC sputtering from oxygen-deficient ZnO targets to lower the cost of thin film solar cells.展开更多
In the past two decades, organic solar cells （OSCs） have at- tracted significant attention owing to their merits of achieving light-weight, flexible, low-cost devices [1,2]. Ternary OSC as an efficient way to improv...In the past two decades, organic solar cells （OSCs） have at- tracted significant attention owing to their merits of achieving light-weight, flexible, low-cost devices [1,2]. Ternary OSC as an efficient way to improve the power conversion efficiencies （PCEs） of OSCs has inspired great interest from researchers to investigate ternary OSCs and result in many efficient de- vices. Ternary OSCs allow collecting high- and low-energy photons by separated semiconductors in a single active layer to minimize the thermalization loss and broaden absorption range to improve the performance of OSCs. However, most reported ternary OSCs only have active layer of about 100 nm in thickness.展开更多
The BaFe_(0.9)Sn_(0.1)O_(3)-BaCo_(0.02)^(Ⅱ)Co_(0.04)^(Ⅲ)Bi_(0.94)O_(3)composite thick films were prepared by screen printing.X-ray diffraction(XRD)analysis confirms that the composite films are still composed of BaF...The BaFe_(0.9)Sn_(0.1)O_(3)-BaCo_(0.02)^(Ⅱ)Co_(0.04)^(Ⅲ)Bi_(0.94)O_(3)composite thick films were prepared by screen printing.X-ray diffraction(XRD)analysis confirms that the composite films are still composed of BaFe_(0.9)Sn_(0.1)O_(3)-BaCo_(0.02)^(Ⅱ)Co_(0.04)^(Ⅲ)Bi_(0.94)O_(3)phases.For the prepared BaFe_(0.9)Sn_(0.1)O_(3)-BaCo_(0.02)^(Ⅱ)Co_(0.04)^(Ⅲ)Bi_(0.94)O_(3)composite thick films,a linear relationship between the logarithmic resistivity and the reciprocal of the absolute temperature is observed,indicating an excellent NTC thermistor characteristic.The values of resistivity at 25℃,thermistor constant and activation energy,decreasing with BaCo_(0.02)^(Ⅱ)Co_(0.04)^(Ⅲ)Bi_(0.94)O_(3)content increasing,are in the range of 8.9-92,990Ω·cm,1,126-3,777 K and 0.097-0.325 eV,respectively.Impedance analysis shows that at higher BaCo_(0.02)^(Ⅱ)Co_(0.04)^(Ⅲ)Bi_(0.94)O_(3)content,the electrical properties of the composite films are mainly attributed to the contribution of grains and grain boundaries.With the gradual decrease of BaCo_(0.02)^(Ⅱ)Co_(0.04)^(Ⅲ)Bi_(0.94)O_(3)content,the grain boundaries affect strongly the electrical properties of the composite films.展开更多
Finite element method and ultrafast thermoelasticity model are combined to simulate the microbump formation irradiated by a femtosecond laser. It has been shown that the effect of microbump formation is related to the...Finite element method and ultrafast thermoelasticity model are combined to simulate the microbump formation irradiated by a femtosecond laser. It has been shown that the effect of microbump formation is related to the characteristic of incident femtosecond laser and the thermoelasticity properties of the film. The numerical results exhibit good agreements with the experimental results in both the shape and height of the conical microbump structure, which verify the effectiveness of the ultrafast thermoelasticity model in experiments. It should be helpful for selecting appropriate materials for nanotexturing of thin films by ultrafast lasers.展开更多
The fabrication of near-net-shaped objects of RE123 superconductors by 'infiltration processing' is discussed. Near-net-shape processing involves the infiltration of preshaped porous green bodies of either 211...The fabrication of near-net-shaped objects of RE123 superconductors by 'infiltration processing' is discussed. Near-net-shape processing involves the infiltration of preshaped porous green bodies of either 211 or yttria phases by liquids containing barium cuprates and copper oxides followed by a controlled peritectic solidification. The process yields poly- and also single-crystalline superconducting objects with a shrinkage of less than half of one percent of the green bodies. The preservation of the initial structure of the green bodies results in fabrication of RE 123 in a wide variety of dimensions and complex shapes. The demonstrated products include bulk components like cylinders, single domain thick films on a variety of substrates, freestanding fabrics and open porous superconducting foams. This paper presents a comprehensive description of the infiltration processing technique and the resulting microstructures of the superconducting bodies. The advantages of this technique and practical applications of the processed superconducting structures are highlighted.展开更多
文摘Europium and terbium coordination polymers of pyridine-3-carboxylic acid were in-situ composed with ethyt methacrylate （ EMA ）. With the polymerization of EMA monomer and the formation of europium and terbium coordination polymers of pyridiae- 3-carboxylic acid, the transparent hybrid thick fihns composed of [ Eu（ NIC ）3 ]n （ [ Tb（ NIC）3 ]n ） and poly ethyl mettuwrylate （ PEMA ） have been prepared. The luminescence properties and energy transfer of these polymeric composites were studied with absorption spectra, fluorescent excitation trod emission spectra in detail. All the hybrid thick films composed of terbium coordination polymer show the characteristic strong green emission of terbium ions, which implies the same energy transfer mechanism as the pure complex and the hybrid composite film is a suitable sabstrate for the luminescence of terbium ions. In the range of camposing concentration of luminescent species （0.01,0.025,0.05,0.1 mmol /15 mL EMA ）, emission intensities increase with the increasing of corresponding composing concentration and the concentration quenching effect does not take place.
基金supported by the National Natural Science Foundation of China(No.51602055)the Natural Science Foundation of Fujian Province(No.2019J01228).
文摘Er^(3+)-doped Ba_(0.85)Ca_(0.15)Ti_(0.9)Zr_(0.1O3)(xEr-BCTZ,x=0,0.005,0.01,0.015)multifunctional thick films were prepared by the tape-casting method,using sol-gel-derived nano-sized powders as the matrix material.The surface morphologies,photoluminescence,and electrical properties were investigated.Dense microstructures with pure perovskite structure were obtained in the thick films.By doping an appropriate amount of Er^(3+),the samples exhibit superior up-conversion photoluminescence performance and simultaneously enhanced electrical performances.In addition,relatively higher texture fractions(with the largest value of 83.5%)were realized through introducing plate-like BaTiO_(3) templates to make the thick film grow by the[001]_(c) orientation.And the ferro-/piezoelectric properties of the thick films were further improved,showing potential in the applications of micro-optoelectronic devices.
基金financial support of Ministry of Education,Science and Technological Development of the Republic of Serbia trough the project Ⅲ45021.
文摘The preparation and properties of thick flexible three-phase composite films based on lead zirconium titanate(PZT) and various ferrites(nickel zinc ferrite(NZF) and cobalt ferrite(CF)) were reported in this study. Properties of three-phase composite films were compared with pure polyvinylidene fluoride(PVDF) and PZT–PVDF films. X-ray diffraction data indicated the formation of well crystallized structure of PZT and NZF/CF phases, without the presence of undesirable phases. Scanning electron micrographs showed that the ceramic particles were dispersed homogeneously in the PVDF matrix and atomic force microscopy confirmed that the size of the particles is around 30 nm. Non-saturated hysteresis loops were evident in all samples due to the presence of highly conductive ferrite phases. Under magnetic field of 10 k Oe, composite films exhibited a typical ferromagnetic response. Dielectric properties were investigated in the temperature range from –128 to 250 ℃ and frequency range of 400 Hz–1 MHz. The results showed that the value of dielectric constant of the PVDF/PZT/ferrite composites increased about 25% above the one obtained for pure PVDF.
基金supported by the National Natural Science Foundation of China(Grant Nos.51972144,U1806221 and U2006218)the Shandong Provincial Natural Science Foundation(Grant No.ZR2020KA003)+2 种基金the Project of“20 Items of University”of Jinan(Grant Nos.T202009 and T201907)the Introduction Program of Senior Foreign Experts(G2021024003L)the Shandong Provincial Key Research and Development Plan(Grant No.2022CXPT045).
文摘The BiFeO3-based film is one of the most promising candidates for lead-free piezoelectric film devices.In this work,the 1μm-thick Bi(Fe_(0.93)Mn_(0.05)Ti_(0.02))O_(3)(BFMT)films are grown on the ITO/glass substrate using a sol-gel method combined with spin-coating and layer-by-layer annealing technique.These films display a large saturated polarization of 95μC/cm^(2),and a remanent polarization of 70μC/cm^(2).Especially,the films are self-poled caused by an internal bias field,giving rise to asymmetric polarization-electric field(P-E)loops with a positive shift along the x-axis.A stable self-polarization state is maintained during the applied electric field increasing to 1500 kV/cm and then decreasing back.The weak dependence of P-E loops on frequency(1-50 kHz)and temperature(25-125°C)indicate that the internal bias field can be stable within a certain frequency and temperature range.These results demonstrate that the self-polarized BFMT thick films can be integrated into devices without any poling process,with promising applications in micro-electro-mechanical systems.
基金partly supported by the National Natural Science Fund of China(Nos.61306004,51002179,11304354 and 51272270)the STS-Network Plan+2 种基金the CAS(No.KFJ-EW-STS-043)the Natural Science Fund of Jiangsu Province(No.BK20130263)the Collaborative Innovation Center of Suzhou Nano Science and Technology,and the PAPD and USTS Cooperative Innovation Center
文摘Er ions are implanted into the GaN thick films grown by hydride vapor phase epitaxy. The implantation energy is 200 keV and the implantation doses are 1 × 10^13, 1 × 10^14, 1 × 10^15, and 5 × 10^15 atom/cm2, respectively. The effects of the implantation dose and annealing temperature on the GaN band-edge luminescence are investigated. The cathodoluminescence spectra from 82 to 323 K are measured for 1 × 10^15 atom/cm2- implanted GaN annealed at 1100℃. Luminescence peaks at 356, 362, 376, 390, and 414 nm are observed on the 82 K cathodoluminescence spectrum. When the temperature is increased to 150 K, the intensities of the 356 and 414 nm peaks are nearly unchanged and the 362,376, and 390 nm peaks disappear. The intensity ratio of 538 nm （2H11/2 →4 4I15/2） and 559 nm （4A3/2 →4I15/2） is increased with the increase in temperature. We try to shed light on the above interesting phenomena.
基金This work was supported by the National Natu- ral Science Foundation of China (No. 90206002 and 90201013)the National "863" Project of China (No. 2002AA313030).
文摘SiO_2/TiO_2/methylcellulose composite materials processed by the sol-gel technique were studied for optical waveguide applications. With the help of methylcellulose, an organic binder, SiO2/TiO2/methylcellulose hybrid thick films were prepared by a single spin-coating processes. After annealing at 70 °C for an hour, 2.5-μm crack-free and dense organic-inorganic hybrid optical films with a refractive index of 1.537 were achieved. Optical losses of plane waveguide made up of those films and ordinary slide glass substrate are around 0.3 dB/cm at 650 nm. Scanning electronmicroscopy (SEM) and UV-visible spectroscopy (UV-VIS), have been used to characterize the thick films.
基金The authors would like to acknowledge the support from the National Natural Science Foundation of China(No.10874130 and No.51272178).
文摘50μm-thick(Pb_(0.9)7La_(0.02))(Zr_(0.92)Sn_(0.05)Ti_(0.03))O_(3) antiferroelectric(AFE)thick films with different amount of 0.8Pb_O-0.2B_(2)O_(3) glass additions were fabricated by the screen-printing method on alumina substrate,which was pre-coated with Pt as electrode.The effects of glass additions on dielectric properties and energy storage performance were investigated in details.Due to the enhancement of breakdown strength(BDS)of the specimens by the addition of glass,the energy storage performances of the thick films could be greatly improved.As a result,with 3%glass addition,the BDS of the specimens were as high as 475 kV/cm,the maximum polarization of 34.8μC/cm^(2) and the maximum recoverable energy storage density of 7.4 J/cm^(3) were obtained.The results indicated the(Pb_(0.9)7La_(0.02))(Zr_(0.92)Sn_(0.05)Ti_(0.03))O_(3) (PLZST)thick films have a promising potential application in capacitors for pulsed power systems.
基金Projects(5110205551462005)supported by the National Natural Science Foundation of China
文摘Thick-film thermistor with negative temperature coefficient（NTC）, low room-temperature resistivity and modest thermistor constant was screen-printed on the alumina substrate by the combination of 30.94III0.04II0.02 B OBi Coa Co with Ba0.5Bi0.5Fe0.9Sn0.1O3. The electrical properties of the thick films were characterized by a digital multimeter, a Keithley 2400 and an impedance analyzer. The results show that with the Ba0.5Bi0.5Fe0.9Sn0.1O3 content increasing from 0.05 to 0.25, the values of room-temperature resistivity, thermistor constant and peak voltage of the thick films increases and are in the ranges of 1.47-26.5 ？·cm, 678-1345 K and 18.9-47.0 V, respectively. The corresponding current at the peak voltage of the thick films decreases and is in the range of 40-240 m A. The impedance spectroscopy measurement demonstrates that the as-prepared thick films show the abnormal electrical heterogeneous microstructure, consisting of high-resistive grains and less resistive grain boundary regions. It can be concluded that the addition of Ba0.5Bi0.5Fe0.9Sn0.1O3 into 30.94III0.04II0.02 Ba Co OBi Co improves the thermistor behavior and but also deteriorates the current characteristics.
基金Project supported by the Foundation of the Ministry of Science and Technology of China (Grant No. 2009GJE00033)the National Natural Youth Fund of China (Grant No. 61001025)the National Program for Science and Technology Development of Guangdong Province,China (Grant No. 2010B090400314)
文摘In this paper, the oriented M-type barium ferrite （BaM） thick films with different thicknesses are prepared by tape casting. It is found that the crystallographic alignment degree （f）, the pore and the squareness ratio （Mr/Ms） are not affected by the thickness of the film. XRD and SEM results show that the thick film has hexagonal morphology with a crystal texture of c-axis grains perpendicular to film plane. The hysteresis curve indicates that the BaM thick film exhibits a self-biased property with a remanent magnetization of 3.30 T, a squareness ratio （Mr/Ms） of 0.81, and a coercivity of 0.40 T. The results show that the BaM thick film has potential for use in self-biasing microwave devices, and also proves that the tape casting technique is capable of fabricating high-quality barium ferrite films, thus providing a unique opportunity to realize the large area production of thick film.
基金financial support for this work from the Deutsche Forschungsgemeinschaft(DFG)under WE4972/2 and GRK2495Ffunding from the Slovenian Research Agency within programmes P2-0105 and P2-0393 and projects J2-2497,J2-3041,and bilateral project BIeDE/20-21-012.
文摘Room-temperature fabrication of functional ceramic films using powder aerosol deposition(AD)is important for practical applications.However,the as-processed ferroelectric films show unusual temperature-dependent dielectric response,including enhanced conductivity in the as-processed state and subsequent significant increase in the permittivity following heat treatment.In this work,we investigate the influence of the residual internal stresses developed during the high-impact consolidation process on the dielectric response.Moreover,the recombination of charged defects generated during deposition is driven by the temperature and the atmospheric condition during the heat treatment as well as the carrier gas type used during deposition.Thermal treatment up to 500℃ in different atmospheres was used to tune the dielectric and ferroelectric response,highlighting that irrespective of the type of carrier gas,AD deposition process induces charged defects in polar oxide ceramics that can be reduced through heat-treatment far-below their bulk sintering temperature.Macroscopic electromechanical properties are contrasted to in-situ heating scanning transmission electron microscopy to observe possible local effects,such as crystallization,grain growth,crystal defect structure,or grain reorientation.In addition X-ray diffraction and X-ray photoelectron spectroscopy studies were conducted to gain insight into the effect of annealing on the crystal structure and local moisture adsorption.
基金This work was supported by the State Key Program of China (No.2004CB719803)the National Natural Science Foundation of China (No.50173015.50218001,and 60377041).
文摘A true single-step process suitable for fabrication of micro-periodic structure in polymer films by twophoton initiated photopolymerization and laser ablation is presented. By the right choice of the irradiation energy, the irradiated zone is modified or ablated in the 1.44-μm-thick film. The mechanism of grating generation and the potential application of the gratings in integrated optics are discussed.
基金supported by the National "973" Program of China(Nos.2007CB936704 and 2009CB939903)the Natural Science Foundation of Shanghai,China(No.11ZR1441900)the Science and Technology Commission of Shanghai,China(Nos.10520706700 and 0952nm06500)
文摘Intrinsic zinc oxide films, normally deposited by radio frequency （RF） sputtering, are fabricated by direct current （DC） sputtering. The oxygen-deficient targets are prepared via a newly developed double crucible method. The 800-nm-thick film obtaines significantly higher carrier mobility compareing with that of the 800-nm-thick ZnO film. This is achieved by the widely used RF sputtering, which favors the prevention of carrier recombination at the interfaces and reduction of the series resistance of solar cells. The optimal ZnO film is used in a Cu （ln, Ga） Se2 （CIGS） solar cell with a high efficiency of 11.57%. This letter demonstrates that the insulating ZnO films can be deposited by DC sputtering from oxygen-deficient ZnO targets to lower the cost of thin film solar cells.
文摘In the past two decades, organic solar cells （OSCs） have at- tracted significant attention owing to their merits of achieving light-weight, flexible, low-cost devices [1,2]. Ternary OSC as an efficient way to improve the power conversion efficiencies （PCEs） of OSCs has inspired great interest from researchers to investigate ternary OSCs and result in many efficient de- vices. Ternary OSCs allow collecting high- and low-energy photons by separated semiconductors in a single active layer to minimize the thermalization loss and broaden absorption range to improve the performance of OSCs. However, most reported ternary OSCs only have active layer of about 100 nm in thickness.
基金the National Natural Science Foundation of China(No.51102055)the Natural Science Foundation of Guangxi(Nos.2010GXNSFA013036 and 2011GXNSFA018028)。
文摘The BaFe_(0.9)Sn_(0.1)O_(3)-BaCo_(0.02)^(Ⅱ)Co_(0.04)^(Ⅲ)Bi_(0.94)O_(3)composite thick films were prepared by screen printing.X-ray diffraction(XRD)analysis confirms that the composite films are still composed of BaFe_(0.9)Sn_(0.1)O_(3)-BaCo_(0.02)^(Ⅱ)Co_(0.04)^(Ⅲ)Bi_(0.94)O_(3)phases.For the prepared BaFe_(0.9)Sn_(0.1)O_(3)-BaCo_(0.02)^(Ⅱ)Co_(0.04)^(Ⅲ)Bi_(0.94)O_(3)composite thick films,a linear relationship between the logarithmic resistivity and the reciprocal of the absolute temperature is observed,indicating an excellent NTC thermistor characteristic.The values of resistivity at 25℃,thermistor constant and activation energy,decreasing with BaCo_(0.02)^(Ⅱ)Co_(0.04)^(Ⅲ)Bi_(0.94)O_(3)content increasing,are in the range of 8.9-92,990Ω·cm,1,126-3,777 K and 0.097-0.325 eV,respectively.Impedance analysis shows that at higher BaCo_(0.02)^(Ⅱ)Co_(0.04)^(Ⅲ)Bi_(0.94)O_(3)content,the electrical properties of the composite films are mainly attributed to the contribution of grains and grain boundaries.With the gradual decrease of BaCo_(0.02)^(Ⅱ)Co_(0.04)^(Ⅲ)Bi_(0.94)O_(3)content,the grain boundaries affect strongly the electrical properties of the composite films.
基金the Shanghai Science and Technology Committee (No.06SP07003 and 0652nm005)the National"973"Program of China (No.2006CB806000).
文摘Finite element method and ultrafast thermoelasticity model are combined to simulate the microbump formation irradiated by a femtosecond laser. It has been shown that the effect of microbump formation is related to the characteristic of incident femtosecond laser and the thermoelasticity properties of the film. The numerical results exhibit good agreements with the experimental results in both the shape and height of the conical microbump structure, which verify the effectiveness of the ultrafast thermoelasticity model in experiments. It should be helpful for selecting appropriate materials for nanotexturing of thin films by ultrafast lasers.
基金German Federal Ministry of Higher Education and Research(BMBF)(No.13N1571/l)
文摘The fabrication of near-net-shaped objects of RE123 superconductors by 'infiltration processing' is discussed. Near-net-shape processing involves the infiltration of preshaped porous green bodies of either 211 or yttria phases by liquids containing barium cuprates and copper oxides followed by a controlled peritectic solidification. The process yields poly- and also single-crystalline superconducting objects with a shrinkage of less than half of one percent of the green bodies. The preservation of the initial structure of the green bodies results in fabrication of RE 123 in a wide variety of dimensions and complex shapes. The demonstrated products include bulk components like cylinders, single domain thick films on a variety of substrates, freestanding fabrics and open porous superconducting foams. This paper presents a comprehensive description of the infiltration processing technique and the resulting microstructures of the superconducting bodies. The advantages of this technique and practical applications of the processed superconducting structures are highlighted.
