In this work,flexible photothermal PVA/Ti_(2)O_(3) composite films with different amount(0 wt%,5 wt%,10 wt%,15 wt%)of Ti_(2)O_(3) particles modified by steric acid were prepared by a simple solution casting method.The...In this work,flexible photothermal PVA/Ti_(2)O_(3) composite films with different amount(0 wt%,5 wt%,10 wt%,15 wt%)of Ti_(2)O_(3) particles modified by steric acid were prepared by a simple solution casting method.The microstructures,XRD patterns,FTIR spectra,UV-Vis-NIR spectra thermo-conductivity,thermo-stability and photothermal effects of these composite films were all characterized.These results indicated that Ti_(2)O_(3) particles were well dispersed throughout the polyvinyl alcohol(PVA)matrix in the PVA/Ti_(2)O_(3) composite films.And Ti_(2)O_(3) particles could also effectively improve the photothermal properties of the composite films which exhibited high light absorption and generated a high temperature(about 57.4℃for film with 15 wt%Ti_(2)O_(3) amount)on the surface when it was irradiated by a simulated sunlight source(1 kW/m^(2)).展开更多
Hafnia-based ferroelectric materials, like Hf_(0.5)Zr_(0.5)O_(2)(HZO), have received tremendous attention owing to their potentials for building ultra-thin ferroelectric devices. The orthorhombic(O)-phase of HZO is fe...Hafnia-based ferroelectric materials, like Hf_(0.5)Zr_(0.5)O_(2)(HZO), have received tremendous attention owing to their potentials for building ultra-thin ferroelectric devices. The orthorhombic(O)-phase of HZO is ferroelectric but metastable in its bulk form under ambient conditions, which poses a considerable challenge to maintaining the operation performance of HZO-based ferroelectric devices. Here, we theoretically addressed this issue that provides parameter spaces for stabilizing the O-phase of HZO thin-films under various conditions. Three mechanisms were found to be capable of lowering the relative energy of the O-phase, namely, more significant surface-bulk portion of(111) surfaces, compressive c-axis strain,and positive electric fields. Considering these mechanisms, we plotted two ternary phase diagrams for HZO thin-films where the strain was applied along the in-plane uniaxial and biaxial, respectively. These diagrams indicate the O-phase could be stabilized by solely shrinking the film-thickness below 12.26 nm, ascribed to its lower surface energies. All these results shed considerable light on designing more robust and higher-performance ferroelectric devices.展开更多
The structure–property relationship at interfaces is difficult to probe for thermoelectric materials with a complex interfacial microstructure.Designing thermoelectric materials with a simple,structurally-uniform int...The structure–property relationship at interfaces is difficult to probe for thermoelectric materials with a complex interfacial microstructure.Designing thermoelectric materials with a simple,structurally-uniform interface provides a facile way to understand how these interfaces influence the transport properties.Here,we synthesized Bi_(2−x)Sb_(x)Te_(3)(x=0,0.1,0.2,0.4)nanoflakes using a hydrothermal method,and prepared Bi_(2−x)Sb_(x)Te_(3)thin films with predominantly(0001)interfaces by stacking the nanoflakes through spin coating.The influence of the annealing temperature and Sb content on the(0001)interface structure was systematically investigated at atomic scale using aberration-corrected scanning transmission electron microscopy.Annealing and Sb doping facilitate atom diffusion and migration between adjacent nanoflakes along the(0001)interface.As such it enhances interfacial connectivity and improves the electrical transport properties.Interfac reactions create new interfaces that increase the scattering and the Seebeck coefficient.Due to the simultaneous optimization of electrical conductivity and Seebeck coefficient,the maximum power factor of the Bi_(1.8)Sb_(0.2)Te_(3)nanoflake films reaches 1.72 mW m^(−1)K^(−2),which is 43%higher than that of a pure Bi_(2)Te_(3)thin film.展开更多
We report the performances of a chalcopyrite Cu(In, Ga)Se<sub>2 </sub>CIGS-based thin-film solar cell with a newly employed high conductive n-Si layer. The data analysis was performed with the help of the ...We report the performances of a chalcopyrite Cu(In, Ga)Se<sub>2 </sub>CIGS-based thin-film solar cell with a newly employed high conductive n-Si layer. The data analysis was performed with the help of the 1D-Solar Cell Capacitance Simulator (1D-SCAPS) software program. The new device structure is based on the CIGS layer as the absorber layer, n-Si as the high conductive layer, i-In<sub>2</sub>S<sub>3</sub>, and i-ZnO as the buffer and window layers, respectively. The optimum CIGS bandgap was determined first and used to simulate and analyze the cell performance throughout the experiment. This analysis revealed that the absorber layer’s optimum bandgap value has to be 1.4 eV to achieve maximum efficiency of 22.57%. Subsequently, output solar cell parameters were analyzed as a function of CIGS layer thickness, defect density, and the operating temperature with an optimized n-Si layer. The newly modeled device has a p-CIGS/n-Si/In<sub>2</sub>S<sub>3</sub>/Al-ZnO structure. The main objective was to improve the overall cell performance while optimizing the thickness of absorber layers, defect density, bandgap, and operating temperature with the newly employed optimized n-Si layer. The increase of absorber layer thickness from 0.2 - 2 µm showed an upward trend in the cell’s performance, while the increase of defect density and operating temperature showed a downward trend in solar cell performance. This study illustrates that the proposed cell structure shows higher cell performances and can be fabricated on the lab-scale and industrial levels.展开更多
MoS2/Zr composite films were deposited on the cemented carbide YT14 （WC＋14%TiC＋6%Co） by medium-frequency magnetron sputtered and coupled with multi-arc ion plated techniques.The influence of negative bias voltage ...MoS2/Zr composite films were deposited on the cemented carbide YT14 （WC＋14%TiC＋6%Co） by medium-frequency magnetron sputtered and coupled with multi-arc ion plated techniques.The influence of negative bias voltage on the composite film properties,including adhesion strength,micro-hardness,thickness and tribological properties were investigated.The results showed that proper negative bias voltage could significantly improve the mechanical and tribological properties of composite films.The effects of negative bias voltage on film properties were also put forward.The optimal negative bias voltage was -200 V under this experiment conditions.The obtained composite films were dense,the adhesion strength was about 60 N,the thickness was about 2.4 μm,and the micro-hardness was about 9.0 GPa.The friction coefficient and wear rate was 0.12 and 2.1×10-7 cm3/N·m respectively after 60 m sliding operation against hardened steel under a load of 20 N and a sliding speed of 200 rev·min-1.展开更多
Theβ-Ga_(2)O_(3)films with different thicknesses are prepared by an atomic layer deposition system.The influence of film thickness on the crystal quality is obvious,indicating that the thicker films perform better cr...Theβ-Ga_(2)O_(3)films with different thicknesses are prepared by an atomic layer deposition system.The influence of film thickness on the crystal quality is obvious,indicating that the thicker films perform better crystal quality,which is verified from x-ray diffraction(XRD)and scanning electron microscope(SEM)results.The Ga_(2)O_(3)-based solar blind photodetectors with different thicknesses are fabricated and studied.The experimental results show that the responsivity of the photodetectors increases exponentially with the increase of the film thickness.The photodetectors with inter-fingered structure based on 900 growth cyclesβ-Ga_(2)O_(3)active layers(corresponding film thickness of 58 nm)exhibit the best performances including a low dark current of 134 fA,photo-to-dark current ratio of 1.5×10^(7),photoresponsivity of 1.56 A/W,detectivity of 2.77×10^(14)Jones,and external quantum efficiency of 764.49%at a bias voltage of 10 V under 254-nm DUV illumination.The photoresponse rejection ratio(R_(254)/R_(365))is up to 1.86×10^(5).In addition,we find that the photoelectric characteristics also depend on the finger spacing of the MSM structure.As the finger spacing decreases from 50μm to10μW,the photoresponsivity,detectivity,and external quantum efficiency increase significantly.展开更多
Low-dimensional halide perovskites have become the most promising candidates for X-ray imaging,yet the issues of the poor chemical stability of hybrid halide perovskite,the high poisonousness of lead halides and the r...Low-dimensional halide perovskites have become the most promising candidates for X-ray imaging,yet the issues of the poor chemical stability of hybrid halide perovskite,the high poisonousness of lead halides and the relatively low detectivity of the lead-free halide perovskites which seriously restrain its commercialization.Here,we developed a solution inverse temperature crystal growth(ITCG)method to bring-up high quality Cs_(3)Cu_(2)I_(5)crystals with large size of centimeter order,in which the oleic acid(OA)is introduced as an antioxidative ligand to inhibit the oxidation of cuprous ions effieiently,as well as to decelerate the crystallization rate remarkalby.Based on these fine crystals,the vapor deposition technique is empolyed to prepare high quality Cs_(3)Cu_(2)I_(5)films for efficient X-ray imaging.Smooth surface morphology,high light yields and short decay time endow the Cs_(3)Cu_(2)I_(5)films with strong radioluminescence,high resolution(12 lp/mm),low detection limits(53 nGyair/s)and desirable stability.Subsequently,the Cs_(3)Cu_(2)I_(5)films have been applied to the practical radiography which exhibit superior X-ray imaging performance.Our work provides a paradigm to fabricate nonpoisonous and chemically stable inorganic halide perovskite for X-ray imaging.展开更多
Hybrid organic–inorganic perovskite thin films have attracted much attention in optoelectronic and information fields because of their intriguing properties. Due to quantum confinement effects, ultrathin films in nm ...Hybrid organic–inorganic perovskite thin films have attracted much attention in optoelectronic and information fields because of their intriguing properties. Due to quantum confinement effects, ultrathin films in nm scale usually show special properties. Here, we report on the growth of methylammonium lead iodide(MAPbI_(3)) ultrathin films via co-deposition of PbI_2 and CH_3NH_3I(MAI) on chemical-vapor-deposition-grown monolayer MoS_(2) as well as the corresponding photoluminescence(PL) properties at different growing stages. Atomic force microscopy and scanning electron microscopy measurements reveal the MoS_(2) tuned growth of MAPbI_(3) in a Stranski–Krastanov mode. PL and Kelvin probe force microscopy results confirm that MAPbI_(3) /MoS_(2) heterostructures have a type-Ⅱ energy level alignment at the interface. Temperaturedependent PL measurements on layered MAPbI_(3) (at the initial stage) and on MAPbI_(3) crystals in averaged size of 500 nm(at the later stage) show rather different temperature dependence as well as the phase transitions from tetragonal to orthorhombic at 120 and 150 K, respectively. Our findings are useful in fabricating MAPbI_(3) /transition-metal dichalcogenide based innovative devices for wider optoelectronic applications.展开更多
We investigate the effect of ion irradiation on MgB_(2) thin films with small grains of approximately 122 nm and 140 nm.The flux pinning by grain boundaries is insignificant in the pristine MgB_(2) films due to good i...We investigate the effect of ion irradiation on MgB_(2) thin films with small grains of approximately 122 nm and 140 nm.The flux pinning by grain boundaries is insignificant in the pristine MgB_(2) films due to good inter-grain connectivity,but is significantly improved after 120-keV Mn-ion irradiation.The scaling behavior of the flux pinning force density for the ion-irradiated MgB_(2) thin films with nanoscale grains demonstrates the predominance of pinning by grain boundaries,in contrast to the single-crystalline MgB_(2) films where normal point pinning was dominant after low-energy ion irradiation.These results suggest that irradiation-induced defects can accumulate near the grain boundaries in metallic MgB_(2) superconductors.展开更多
As a thin film solar cell absorber material, antimony selenide (Sb<sub>2</sub>Se<sub>3</sub>) has become a potential candidate recently because of its unique optical and electrical properties a...As a thin film solar cell absorber material, antimony selenide (Sb<sub>2</sub>Se<sub>3</sub>) has become a potential candidate recently because of its unique optical and electrical properties and easy fabrication method. X-ray photoelectron spectroscopy (XPS) was used to determine the stoichiometry and composition of electroless Sb<sub>2</sub>Se<sub>3</sub> thin films using depth profile studies. The surface layers were analyzed nearly stoichiometric. But the abundant amount of antimony makes the inner layer electrically more conductive.展开更多
For the crystalline temperature of BaSnO_(3)(BTO)was above 650℃,the transparent conductive BTO-based films were always deposited above this temperature on epitaxy substrates by pulsed laser deposition or molecular be...For the crystalline temperature of BaSnO_(3)(BTO)was above 650℃,the transparent conductive BTO-based films were always deposited above this temperature on epitaxy substrates by pulsed laser deposition or molecular beam epitaxy till now which limited there application in low temperature device process.In the article,the microstructure,optical and electrical of BTO and In_(2)O_(3) mixed transparent conductive BaInSnO_(x)(BITO)film deposited by filtered cathodic vacuum arc technique(FCVA)on glass substrate at room temperature were firstly reported.The BITO film with thickness of 300 nm had mainly In_(2)O_(3) polycrystalline phase,and minor polycrystalline BTO phase with(001),(011),(111),(002),(222)crystal faces which were first deposited at room temperature on amorphous glass.The transmittance was 70%–80%in the visible light region with linear refractive index of 1.94 and extinction coefficient of 0.004 at 550-nm wavelength.The basic optical properties included the real and imaginary parts,high frequency dielectric constants,the absorption coefficient,the Urbach energy,the indirect and direct band gaps,the oscillator and dispersion energies,the static refractive index and dielectric constant,the average oscillator wavelength,oscillator length strength,the linear and the third-order nonlinear optical susceptibilities,and the nonlinear refractive index were all calculated.The film was the n-type conductor with sheet resistance of 704.7Ω/□,resistivity of 0.02Ω⋅cm,mobility of 18.9 cm2/V⋅s,and carrier electron concentration of 1.6×10^(19) cm^(−3) at room temperature.The results suggested that the BITO film deposited by FCVA had potential application in transparent conductive films-based low temperature device process.展开更多
Sb<sub>2</sub>S<sub>3</sub> has gained tremendous research recently for thin film solar cell absorber material because of their easy synthesis, unique electrical and optical properties. The sto...Sb<sub>2</sub>S<sub>3</sub> has gained tremendous research recently for thin film solar cell absorber material because of their easy synthesis, unique electrical and optical properties. The stoichiometry and composition of electroless Sb<sub>2</sub>S<sub>3</sub> thin films were analyzed using XPS depth profile studies. The surface layers were found nearly stoichiometric. On the other hand, the inner layer was rich in antimony composition making it more conductive electrically.展开更多
Spray pyrolysis method was used to deposit Lutetium Oxide (Lu<sub>2</sub>O<sub>3</sub>) thin films using lutetium (III) chloride as source material and water as oxidizer. Annealing was carried ...Spray pyrolysis method was used to deposit Lutetium Oxide (Lu<sub>2</sub>O<sub>3</sub>) thin films using lutetium (III) chloride as source material and water as oxidizer. Annealing was carried out in argon atmosphere at 450°C for 60 minutes of the films. To investigate the composition and stoichiometry of sprayed as-deposited and annealed Lu<sub>2</sub>O<sub>3</sub> thin films, depth profile studies using X-ray photoelectron spectroscopy (XPS) was done. Nearly stoichiometric was observed for both annealed and as-deposited films in inner and surface layers.展开更多
Ga<sub>2</sub>O<sub>3</sub> thin films were fabricated by spray pyrolysis method using gallium acetylacetonate as source material and water as oxidizer. The films were annealed at 450°C fo...Ga<sub>2</sub>O<sub>3</sub> thin films were fabricated by spray pyrolysis method using gallium acetylacetonate as source material and water as oxidizer. The films were annealed at 450°C for 60 minutes in argon atmosphere. X-ray photoelectron spectroscopy (XPS) depth profile studies were carried out to analyze the stoichiometry and composition of sprayed as-deposited and annealed Ga<sub>2</sub>O<sub>3</sub> thin films. Surface layers and the inner layers of as-deposited and annealed films were found nearly stoichiometric.展开更多
基金Funded by the Youth Backbone Teacher Training Plan in University of Henan Province(No.21220028)Science and Technology Research Project of Henan Province(No.242102321066)+2 种基金Natural Science Foundation of Henan Province(No.232300420312)Henan University of Technology Young Backbone Teacher Training Plan(No.21421260)the Innovation Training Program for College Students in Henan Province(No.202310463046)。
文摘In this work,flexible photothermal PVA/Ti_(2)O_(3) composite films with different amount(0 wt%,5 wt%,10 wt%,15 wt%)of Ti_(2)O_(3) particles modified by steric acid were prepared by a simple solution casting method.The microstructures,XRD patterns,FTIR spectra,UV-Vis-NIR spectra thermo-conductivity,thermo-stability and photothermal effects of these composite films were all characterized.These results indicated that Ti_(2)O_(3) particles were well dispersed throughout the polyvinyl alcohol(PVA)matrix in the PVA/Ti_(2)O_(3) composite films.And Ti_(2)O_(3) particles could also effectively improve the photothermal properties of the composite films which exhibited high light absorption and generated a high temperature(about 57.4℃for film with 15 wt%Ti_(2)O_(3) amount)on the surface when it was irradiated by a simulated sunlight source(1 kW/m^(2)).
基金Project supported by the Fund from the Ministry of Science and Technology(MOST)of China(Grant No.2018YFE0202700)the National Natural Science Foundation of China(Grant Nos.11974422 and 12104504)+2 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB30000000)the Fundamental Research Funds for the Central Universitiesthe Research Funds of Renmin University of China(Grant No.22XNKJ30)。
文摘Hafnia-based ferroelectric materials, like Hf_(0.5)Zr_(0.5)O_(2)(HZO), have received tremendous attention owing to their potentials for building ultra-thin ferroelectric devices. The orthorhombic(O)-phase of HZO is ferroelectric but metastable in its bulk form under ambient conditions, which poses a considerable challenge to maintaining the operation performance of HZO-based ferroelectric devices. Here, we theoretically addressed this issue that provides parameter spaces for stabilizing the O-phase of HZO thin-films under various conditions. Three mechanisms were found to be capable of lowering the relative energy of the O-phase, namely, more significant surface-bulk portion of(111) surfaces, compressive c-axis strain,and positive electric fields. Considering these mechanisms, we plotted two ternary phase diagrams for HZO thin-films where the strain was applied along the in-plane uniaxial and biaxial, respectively. These diagrams indicate the O-phase could be stabilized by solely shrinking the film-thickness below 12.26 nm, ascribed to its lower surface energies. All these results shed considerable light on designing more robust and higher-performance ferroelectric devices.
基金supported by the National Natural Science Foundation of China(52272235)supported by the Fundamental Research Funds for the Central Universities(WUT:2021III016GX).
文摘The structure–property relationship at interfaces is difficult to probe for thermoelectric materials with a complex interfacial microstructure.Designing thermoelectric materials with a simple,structurally-uniform interface provides a facile way to understand how these interfaces influence the transport properties.Here,we synthesized Bi_(2−x)Sb_(x)Te_(3)(x=0,0.1,0.2,0.4)nanoflakes using a hydrothermal method,and prepared Bi_(2−x)Sb_(x)Te_(3)thin films with predominantly(0001)interfaces by stacking the nanoflakes through spin coating.The influence of the annealing temperature and Sb content on the(0001)interface structure was systematically investigated at atomic scale using aberration-corrected scanning transmission electron microscopy.Annealing and Sb doping facilitate atom diffusion and migration between adjacent nanoflakes along the(0001)interface.As such it enhances interfacial connectivity and improves the electrical transport properties.Interfac reactions create new interfaces that increase the scattering and the Seebeck coefficient.Due to the simultaneous optimization of electrical conductivity and Seebeck coefficient,the maximum power factor of the Bi_(1.8)Sb_(0.2)Te_(3)nanoflake films reaches 1.72 mW m^(−1)K^(−2),which is 43%higher than that of a pure Bi_(2)Te_(3)thin film.
文摘We report the performances of a chalcopyrite Cu(In, Ga)Se<sub>2 </sub>CIGS-based thin-film solar cell with a newly employed high conductive n-Si layer. The data analysis was performed with the help of the 1D-Solar Cell Capacitance Simulator (1D-SCAPS) software program. The new device structure is based on the CIGS layer as the absorber layer, n-Si as the high conductive layer, i-In<sub>2</sub>S<sub>3</sub>, and i-ZnO as the buffer and window layers, respectively. The optimum CIGS bandgap was determined first and used to simulate and analyze the cell performance throughout the experiment. This analysis revealed that the absorber layer’s optimum bandgap value has to be 1.4 eV to achieve maximum efficiency of 22.57%. Subsequently, output solar cell parameters were analyzed as a function of CIGS layer thickness, defect density, and the operating temperature with an optimized n-Si layer. The newly modeled device has a p-CIGS/n-Si/In<sub>2</sub>S<sub>3</sub>/Al-ZnO structure. The main objective was to improve the overall cell performance while optimizing the thickness of absorber layers, defect density, bandgap, and operating temperature with the newly employed optimized n-Si layer. The increase of absorber layer thickness from 0.2 - 2 µm showed an upward trend in the cell’s performance, while the increase of defect density and operating temperature showed a downward trend in solar cell performance. This study illustrates that the proposed cell structure shows higher cell performances and can be fabricated on the lab-scale and industrial levels.
基金Funded by the National Natural Science Foundation of China (No.51075237)the National Basic Research Program of China (No.2009CB724402)+3 种基金the Taishan Scholar Program of Shandong Provincethe Outstanding Young Scholar Science Foundation of Shandong (No.JQ200917)the National Natural Science Foundation of Shandong (No.ZR2010EZ002)National High Technology Research and Development Program (No.2009AA044303)
文摘MoS2/Zr composite films were deposited on the cemented carbide YT14 （WC＋14%TiC＋6%Co） by medium-frequency magnetron sputtered and coupled with multi-arc ion plated techniques.The influence of negative bias voltage on the composite film properties,including adhesion strength,micro-hardness,thickness and tribological properties were investigated.The results showed that proper negative bias voltage could significantly improve the mechanical and tribological properties of composite films.The effects of negative bias voltage on film properties were also put forward.The optimal negative bias voltage was -200 V under this experiment conditions.The obtained composite films were dense,the adhesion strength was about 60 N,the thickness was about 2.4 μm,and the micro-hardness was about 9.0 GPa.The friction coefficient and wear rate was 0.12 and 2.1×10-7 cm3/N·m respectively after 60 m sliding operation against hardened steel under a load of 20 N and a sliding speed of 200 rev·min-1.
基金Project supported by the Natural Science Basic Research Program of Shaanxi Province,China(Grant No.2022JQ-701)the Scientific Research Program Funded by Shaanxi Provincial Education Department,China(Grant No.21JK0919)。
文摘Theβ-Ga_(2)O_(3)films with different thicknesses are prepared by an atomic layer deposition system.The influence of film thickness on the crystal quality is obvious,indicating that the thicker films perform better crystal quality,which is verified from x-ray diffraction(XRD)and scanning electron microscope(SEM)results.The Ga_(2)O_(3)-based solar blind photodetectors with different thicknesses are fabricated and studied.The experimental results show that the responsivity of the photodetectors increases exponentially with the increase of the film thickness.The photodetectors with inter-fingered structure based on 900 growth cyclesβ-Ga_(2)O_(3)active layers(corresponding film thickness of 58 nm)exhibit the best performances including a low dark current of 134 fA,photo-to-dark current ratio of 1.5×10^(7),photoresponsivity of 1.56 A/W,detectivity of 2.77×10^(14)Jones,and external quantum efficiency of 764.49%at a bias voltage of 10 V under 254-nm DUV illumination.The photoresponse rejection ratio(R_(254)/R_(365))is up to 1.86×10^(5).In addition,we find that the photoelectric characteristics also depend on the finger spacing of the MSM structure.As the finger spacing decreases from 50μm to10μW,the photoresponsivity,detectivity,and external quantum efficiency increase significantly.
基金the financially support of the National Natural Science Foundation of China(12164051)the Joint Foundation of Provincial Science and Technology Department-Double First-class Construction of Yunnan University(2019FY003016)+4 种基金the Young Top Talent Project of Yunnan Province(YNWR-QNBJ-2018-229)the financially support by Yunnan Major Scientific and Technological Projects(202202AG050016)Advanced Analysis and Measurement Center of Yunnan University for the sample characterization service and the Postgraduate Research and Innovation Foundation of Yunnan University(2021Y036)the financially support of the National Natural Science Foundation of China(62064013)the Application Basic Research Project of Yunnan Province[2019FB130]。
文摘Low-dimensional halide perovskites have become the most promising candidates for X-ray imaging,yet the issues of the poor chemical stability of hybrid halide perovskite,the high poisonousness of lead halides and the relatively low detectivity of the lead-free halide perovskites which seriously restrain its commercialization.Here,we developed a solution inverse temperature crystal growth(ITCG)method to bring-up high quality Cs_(3)Cu_(2)I_(5)crystals with large size of centimeter order,in which the oleic acid(OA)is introduced as an antioxidative ligand to inhibit the oxidation of cuprous ions effieiently,as well as to decelerate the crystallization rate remarkalby.Based on these fine crystals,the vapor deposition technique is empolyed to prepare high quality Cs_(3)Cu_(2)I_(5)films for efficient X-ray imaging.Smooth surface morphology,high light yields and short decay time endow the Cs_(3)Cu_(2)I_(5)films with strong radioluminescence,high resolution(12 lp/mm),low detection limits(53 nGyair/s)and desirable stability.Subsequently,the Cs_(3)Cu_(2)I_(5)films have been applied to the practical radiography which exhibit superior X-ray imaging performance.Our work provides a paradigm to fabricate nonpoisonous and chemically stable inorganic halide perovskite for X-ray imaging.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.11874427 and 11804395)the Fundamental Research Funds for the Central Universities of Central South University (Grant No.2020zzts377)。
文摘Hybrid organic–inorganic perovskite thin films have attracted much attention in optoelectronic and information fields because of their intriguing properties. Due to quantum confinement effects, ultrathin films in nm scale usually show special properties. Here, we report on the growth of methylammonium lead iodide(MAPbI_(3)) ultrathin films via co-deposition of PbI_2 and CH_3NH_3I(MAI) on chemical-vapor-deposition-grown monolayer MoS_(2) as well as the corresponding photoluminescence(PL) properties at different growing stages. Atomic force microscopy and scanning electron microscopy measurements reveal the MoS_(2) tuned growth of MAPbI_(3) in a Stranski–Krastanov mode. PL and Kelvin probe force microscopy results confirm that MAPbI_(3) /MoS_(2) heterostructures have a type-Ⅱ energy level alignment at the interface. Temperaturedependent PL measurements on layered MAPbI_(3) (at the initial stage) and on MAPbI_(3) crystals in averaged size of 500 nm(at the later stage) show rather different temperature dependence as well as the phase transitions from tetragonal to orthorhombic at 120 and 150 K, respectively. Our findings are useful in fabricating MAPbI_(3) /transition-metal dichalcogenide based innovative devices for wider optoelectronic applications.
基金the support of the accelerator group and operators of KOMAC (KAERI (C.K.,J.S.))Project supported by the National Research Foundation (NRF)of Korea through a grant funded by the Korean Ministry of Science and ICT (Grant No.2021R1A2C2010925 (T.P.,Y.H.,J.S.))+2 种基金the Basic Science Research Program through the NRF of Korea funded by the Ministry of Education (Grant Nos.NRF-2019R1F1A1055284 (J.M.L.,W.N.K.)and NRF2021R1I1A1A01043885 (S.G.J.,Y.H.))the National Natural Science Foundation of China (Grant Nos.12035019 (J.L.))the Chinese Scholarship Council (CSC)for fellowship support。
文摘We investigate the effect of ion irradiation on MgB_(2) thin films with small grains of approximately 122 nm and 140 nm.The flux pinning by grain boundaries is insignificant in the pristine MgB_(2) films due to good inter-grain connectivity,but is significantly improved after 120-keV Mn-ion irradiation.The scaling behavior of the flux pinning force density for the ion-irradiated MgB_(2) thin films with nanoscale grains demonstrates the predominance of pinning by grain boundaries,in contrast to the single-crystalline MgB_(2) films where normal point pinning was dominant after low-energy ion irradiation.These results suggest that irradiation-induced defects can accumulate near the grain boundaries in metallic MgB_(2) superconductors.
文摘As a thin film solar cell absorber material, antimony selenide (Sb<sub>2</sub>Se<sub>3</sub>) has become a potential candidate recently because of its unique optical and electrical properties and easy fabrication method. X-ray photoelectron spectroscopy (XPS) was used to determine the stoichiometry and composition of electroless Sb<sub>2</sub>Se<sub>3</sub> thin films using depth profile studies. The surface layers were analyzed nearly stoichiometric. But the abundant amount of antimony makes the inner layer electrically more conductive.
基金Project supported by the Enterprise Science and Technology Correspondent for Guangdong Province,China (Grant No.GDKTP2021015200)。
文摘For the crystalline temperature of BaSnO_(3)(BTO)was above 650℃,the transparent conductive BTO-based films were always deposited above this temperature on epitaxy substrates by pulsed laser deposition or molecular beam epitaxy till now which limited there application in low temperature device process.In the article,the microstructure,optical and electrical of BTO and In_(2)O_(3) mixed transparent conductive BaInSnO_(x)(BITO)film deposited by filtered cathodic vacuum arc technique(FCVA)on glass substrate at room temperature were firstly reported.The BITO film with thickness of 300 nm had mainly In_(2)O_(3) polycrystalline phase,and minor polycrystalline BTO phase with(001),(011),(111),(002),(222)crystal faces which were first deposited at room temperature on amorphous glass.The transmittance was 70%–80%in the visible light region with linear refractive index of 1.94 and extinction coefficient of 0.004 at 550-nm wavelength.The basic optical properties included the real and imaginary parts,high frequency dielectric constants,the absorption coefficient,the Urbach energy,the indirect and direct band gaps,the oscillator and dispersion energies,the static refractive index and dielectric constant,the average oscillator wavelength,oscillator length strength,the linear and the third-order nonlinear optical susceptibilities,and the nonlinear refractive index were all calculated.The film was the n-type conductor with sheet resistance of 704.7Ω/□,resistivity of 0.02Ω⋅cm,mobility of 18.9 cm2/V⋅s,and carrier electron concentration of 1.6×10^(19) cm^(−3) at room temperature.The results suggested that the BITO film deposited by FCVA had potential application in transparent conductive films-based low temperature device process.
文摘Sb<sub>2</sub>S<sub>3</sub> has gained tremendous research recently for thin film solar cell absorber material because of their easy synthesis, unique electrical and optical properties. The stoichiometry and composition of electroless Sb<sub>2</sub>S<sub>3</sub> thin films were analyzed using XPS depth profile studies. The surface layers were found nearly stoichiometric. On the other hand, the inner layer was rich in antimony composition making it more conductive electrically.
文摘Spray pyrolysis method was used to deposit Lutetium Oxide (Lu<sub>2</sub>O<sub>3</sub>) thin films using lutetium (III) chloride as source material and water as oxidizer. Annealing was carried out in argon atmosphere at 450°C for 60 minutes of the films. To investigate the composition and stoichiometry of sprayed as-deposited and annealed Lu<sub>2</sub>O<sub>3</sub> thin films, depth profile studies using X-ray photoelectron spectroscopy (XPS) was done. Nearly stoichiometric was observed for both annealed and as-deposited films in inner and surface layers.
文摘Ga<sub>2</sub>O<sub>3</sub> thin films were fabricated by spray pyrolysis method using gallium acetylacetonate as source material and water as oxidizer. The films were annealed at 450°C for 60 minutes in argon atmosphere. X-ray photoelectron spectroscopy (XPS) depth profile studies were carried out to analyze the stoichiometry and composition of sprayed as-deposited and annealed Ga<sub>2</sub>O<sub>3</sub> thin films. Surface layers and the inner layers of as-deposited and annealed films were found nearly stoichiometric.
