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
In this study,we have explored the ways to fabricate and optimize high-quality ultrathin YBa_(2)Cu_(3)O_(7)-δ(YBCO)films grown on single-crystal(001)SrTiO_(3) substrates.Nearly atomic-flat YBCO films are obtained by ...In this study,we have explored the ways to fabricate and optimize high-quality ultrathin YBa_(2)Cu_(3)O_(7)-δ(YBCO)films grown on single-crystal(001)SrTiO_(3) substrates.Nearly atomic-flat YBCO films are obtained by pulsed laser deposition.Our result shows that the termination of SrTiO_(3) has only a negligible effect on the properties of YBCO.In contrast,we found that capping a non-superconducting oxide layer can generally enhance the superconductivity of YBCO.PrBa_(2)Cu_(3)O_(7),La_(2)CuO_(4),LaMnO_(3),SrTiO_(3),and LaAlO_(3) have been examined as capping layers,and the minimum thickness of superconducting YBCO with capping is~2 unit cells–3 unit cells.This result might be useful in constructing good-performance YBCO-based field effect devices.展开更多
Large area YBCO superconducting thin films were grown on the Zr(Y)O2 substrate at 750 and 800℃ respectively by magnetron sputtering, and the surface morphology was studied with AEM. STM and SEM with an EDS and ECP at...Large area YBCO superconducting thin films were grown on the Zr(Y)O2 substrate at 750 and 800℃ respectively by magnetron sputtering, and the surface morphology was studied with AEM. STM and SEM with an EDS and ECP attachments. The YBCO thin film was found to be a caxis orientated single crystal. At 800℃, the surface out-growths of the thin film Were mainly CuO particles and many small holes were found on the surface. which resulted in rougher surface; whereas, at 750℃, the out-growths were mainly the 123 structure in the form of rod-like and polygon and the surface was much smoother because of less small holes on the surface. The mechanism of the thin film growth and the formation of the small holes on the surface grown at the two temperature were discussed.展开更多
The patterning technologies and process order of high Tc(86K) super-conducting film bolometers have been studied. After the deposition, a conventional lithographic process was used to pattern the films with aqueous so...The patterning technologies and process order of high Tc(86K) super-conducting film bolometers have been studied. After the deposition, a conventional lithographic process was used to pattern the films with aqueous solution of HCl, and then the films were transferred into a tube furnace for annealing to form superconducting film. It eliminates the degradation of patterning process. The bolometric responsivity of approximately 34. 32 V/W is measured, and the detectivity is greater than 1. 62× 108cm · Hz1/2 · W-1, the noise equivalent powers NEP is 2. 1×10-9W.展开更多
Y_(1-x)Ho_xBa_2Cu_3O_(7-δ)(0<x<1) sinsle crystal thin films oriented with the caxis perpendicular to the sur-face were grown by DC magnetron sputtering technique. Target was pieced together with half of YBa_2Cu...Y_(1-x)Ho_xBa_2Cu_3O_(7-δ)(0<x<1) sinsle crystal thin films oriented with the caxis perpendicular to the sur-face were grown by DC magnetron sputtering technique. Target was pieced together with half of YBa_2Cu_3O_(7-δ)(YBCO) and half of HoBa_2Cu_3O_(7-δ)(HBCO) superconducting materials. As the distance between HBCO targetmaterial and substrate is varied , the Ho content in material is changed respectively. When the content of Ho is0. 7 (atom ratio) , the T_c>83K.展开更多
Thin films of superconductors HoBa_2Cu_3O_(7-δ)(HBCO) were prepared by DC-sputtering technique. The epi-taxial growth was controlled by the ratio of the oxygen pressure and Ar pressure (O_2/Ar) , the subetrate temper...Thin films of superconductors HoBa_2Cu_3O_(7-δ)(HBCO) were prepared by DC-sputtering technique. The epi-taxial growth was controlled by the ratio of the oxygen pressure and Ar pressure (O_2/Ar) , the subetrate temperature T_s and the distance of the target to subetrate. Thin films deposited under the optimum conditions (Po_2/P_(Ar)= 1:2 ; T_s=730℃) show a critical temlierature clase to 87K and a transition width less than 1K. X-raydiffraction analysis shows that the films are highiy c-axis oriented. Auger electron spectroscopy depth profilingdemonstrates Ho diffusion into the Zr(Y)O_2 subetrate owing to the Ho subetitution for Y.展开更多
为了验证采用金属单质靶与硫属化合物靶混合溅射法制备Cu_(2)Sn S_(3)(CTS)薄膜及太阳电池的可行性,在镀钼的钠钙玻璃上通过磁控溅射Sn和Cu S靶制备CTS预制层后,再经过低温合金化和高温硫化过程制备CTS薄膜,研究了硫化过程中不同升温速...为了验证采用金属单质靶与硫属化合物靶混合溅射法制备Cu_(2)Sn S_(3)(CTS)薄膜及太阳电池的可行性,在镀钼的钠钙玻璃上通过磁控溅射Sn和Cu S靶制备CTS预制层后,再经过低温合金化和高温硫化过程制备CTS薄膜,研究了硫化过程中不同升温速率对CTS薄膜表面形貌的影响。采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)及配属的能谱仪(EDS)、拉曼散射(Raman)对薄膜的晶体结构、表面和截面形貌、薄膜组分、物相进行表征分析,利用紫外-可见光光度计和霍尔测试系统表征了薄膜的光电特性。在硫化升温速率为35℃/min的条件下,获得了表面致密平整且纯相的单斜结构CTS薄膜,并用CTS薄膜制备了太阳电池。随后在标准测试条件(AM1.5,100 m W/cm^2,300 K)下采用KEITHLEY的2400数字源表测试了电池的I-V特性,其开路电压为299 m V,短路电流密度为16.6 m A/cm^2,光电转换效率为1.18%。结果表明,采用磁控溅射金属单质靶Sn与硫属化合物靶Cu S有望制备出高效CTS薄膜太阳电池。展开更多
The Cu_(2)ZnSnS_(4)thin film was prepared by a facile solution method without vacuum environment and toxic substance.The formation mechanism of the film was studied by transmission electron microscopy(TEM),X-ray diffr...The Cu_(2)ZnSnS_(4)thin film was prepared by a facile solution method without vacuum environment and toxic substance.The formation mechanism of the film was studied by transmission electron microscopy(TEM),X-ray diffraction(XRD),scanning electron microscopy(SEM),energy dispersive X-ray spectroscopy(EDS),and Raman scattering measurements.Through cyclic voltammetry and photo-electricity tests,the electrocatalytic activity of the prepared film as the counter electrode of dye-sensitizedsolar cell was also studied.The results show that the mixed precursor solution mainly consists of Cu2SnS3 nanoparticles and Zn ions.After 550°C annealing process on the precursor film prepared from the mixed solution,Cu_(2)ZnSnS_(4)thin film is obtained.Besides,itis found that the prepared Cu_(2)ZnSnS_(4)thin film has the electrocatalytic activity toward the redox reaction of I3?/I?and the dye-sensitized solar cell with the prepared Cu_(2)ZnSnS_(4)thin film as the counter electrode achieves the efficiency of 1.09%.展开更多
YBa2Cu3O7-x(YBCO) thin film has been epitaxially deposited on (1120) sapphire with Y2O3-stabilized ZrO2 (YSZ) buffer layer and shown a high critical current density Jc of 1. 6×106A/cm2 at 77 K in zero magnetic fi...YBa2Cu3O7-x(YBCO) thin film has been epitaxially deposited on (1120) sapphire with Y2O3-stabilized ZrO2 (YSZ) buffer layer and shown a high critical current density Jc of 1. 6×106A/cm2 at 77 K in zero magnetic field. The orientation relationship of the multilayer film superconductor has been determined. The(001) plane of the YBCO film is parallel to the(100) surface of the YSZ intermediate layer. YSZ buffer layer with(100) preferred orientation is about 20 nm thick and contains element Ba, due to out-diffusion of Ba from YBCO layer. The(100) preferred orientation of YSZ buffer permits the growth of high quality YBCO thin film. Y2BaCuO5 precipitates with small size distribute uniformly in the YBCO thin film and it is favourable to raise critical current density Jc.展开更多
Cu_(2)ZnSnS_(4)薄膜因其元素地壳含量丰富、无毒且具有优异的光电性能,受到研究者的广泛关注。本文基于纳米墨水法用Cd部分取代Zn制成了Cu_(2)(Cd x Zn_(1-x))SnS_(4)(CCZTS)薄膜,研究退火时间和后退火温度对薄膜及其太阳电池性能的影...Cu_(2)ZnSnS_(4)薄膜因其元素地壳含量丰富、无毒且具有优异的光电性能,受到研究者的广泛关注。本文基于纳米墨水法用Cd部分取代Zn制成了Cu_(2)(Cd x Zn_(1-x))SnS_(4)(CCZTS)薄膜,研究退火时间和后退火温度对薄膜及其太阳电池性能的影响。研究结果表明,所制备的薄膜为CCZTS相,无其他杂相,薄膜表面平整且致密,结晶性较好。随着退火时间增加,薄膜的晶粒尺寸有所增大,薄膜太阳电池的pn结质量得到提升,其性能也随之提高。通过对薄膜太阳电池进行后退火处理,分析了吸收层的元素扩散对电池性能的影响,在Cd元素形成梯度分布时,电池性能有所提高。随着后退火温度的增加,其电池性能和pn结质量呈现先提高后下降的趋势。经后退火300℃处理后,电池转换效率最佳,为3.13%。展开更多
Copper-doped Bi_(2)Se_(3)(Cu_(x)Bi_(2)Se_(3))is of considerable interest for tailoring its electronic properties and inducing exotic charge correlations while retaining the unique Dirac surface states.However,the copp...Copper-doped Bi_(2)Se_(3)(Cu_(x)Bi_(2)Se_(3))is of considerable interest for tailoring its electronic properties and inducing exotic charge correlations while retaining the unique Dirac surface states.However,the copper dopants in Cu_(x)Bi_(2)Se_(3) display complex electronic behaviors and may function as either electron donors or acceptors depending on their concentration and atomic sites within the Bi_(2)Se_(3) crystal lattice.Thus,a precise understanding and control of the doping concentration and sites is of both fundamental and practical significance.Herein,we report a solution-based one-pot synthesis of Cu_(x)Bi_(2)Se_(3) nanoplates with systematically tunable Cu doping concentrations and doping sites.Our studies reveal a gradual evolution from intercalative sites to substitutional sites with increasing Cu concentrations.The Cu atoms at intercalative sites function as electron donors while those at the substitutional sites function as electron acceptors,producing distinct effects on the electronic properties of the resulting materials.We further show that Cu_(0.18)Bi_(2)Se_(3) exhibits superconducting behavior,which is not present in Bi_(2)Se_(3),highlighting the essential role of Cu doping in tailoring exotic quantum properties.This study establishes an efficient methodology for precise synthesis of Cu_(x)Bi_(2)Se_(3) with tailored doping concentrations,doping sites,and electronic properties.展开更多
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 Key Research and Development Program of the Ministry of Science and Technology of China(Grants Nos.2017YFA0303002and 2016YFA0300204)the Fundamental Research Funds for the Central Universities,China
文摘In this study,we have explored the ways to fabricate and optimize high-quality ultrathin YBa_(2)Cu_(3)O_(7)-δ(YBCO)films grown on single-crystal(001)SrTiO_(3) substrates.Nearly atomic-flat YBCO films are obtained by pulsed laser deposition.Our result shows that the termination of SrTiO_(3) has only a negligible effect on the properties of YBCO.In contrast,we found that capping a non-superconducting oxide layer can generally enhance the superconductivity of YBCO.PrBa_(2)Cu_(3)O_(7),La_(2)CuO_(4),LaMnO_(3),SrTiO_(3),and LaAlO_(3) have been examined as capping layers,and the minimum thickness of superconducting YBCO with capping is~2 unit cells–3 unit cells.This result might be useful in constructing good-performance YBCO-based field effect devices.
文摘Large area YBCO superconducting thin films were grown on the Zr(Y)O2 substrate at 750 and 800℃ respectively by magnetron sputtering, and the surface morphology was studied with AEM. STM and SEM with an EDS and ECP attachments. The YBCO thin film was found to be a caxis orientated single crystal. At 800℃, the surface out-growths of the thin film Were mainly CuO particles and many small holes were found on the surface. which resulted in rougher surface; whereas, at 750℃, the out-growths were mainly the 123 structure in the form of rod-like and polygon and the surface was much smoother because of less small holes on the surface. The mechanism of the thin film growth and the formation of the small holes on the surface grown at the two temperature were discussed.
文摘The patterning technologies and process order of high Tc(86K) super-conducting film bolometers have been studied. After the deposition, a conventional lithographic process was used to pattern the films with aqueous solution of HCl, and then the films were transferred into a tube furnace for annealing to form superconducting film. It eliminates the degradation of patterning process. The bolometric responsivity of approximately 34. 32 V/W is measured, and the detectivity is greater than 1. 62× 108cm · Hz1/2 · W-1, the noise equivalent powers NEP is 2. 1×10-9W.
文摘Y_(1-x)Ho_xBa_2Cu_3O_(7-δ)(0<x<1) sinsle crystal thin films oriented with the caxis perpendicular to the sur-face were grown by DC magnetron sputtering technique. Target was pieced together with half of YBa_2Cu_3O_(7-δ)(YBCO) and half of HoBa_2Cu_3O_(7-δ)(HBCO) superconducting materials. As the distance between HBCO targetmaterial and substrate is varied , the Ho content in material is changed respectively. When the content of Ho is0. 7 (atom ratio) , the T_c>83K.
文摘Thin films of superconductors HoBa_2Cu_3O_(7-δ)(HBCO) were prepared by DC-sputtering technique. The epi-taxial growth was controlled by the ratio of the oxygen pressure and Ar pressure (O_2/Ar) , the subetrate temperature T_s and the distance of the target to subetrate. Thin films deposited under the optimum conditions (Po_2/P_(Ar)= 1:2 ; T_s=730℃) show a critical temlierature clase to 87K and a transition width less than 1K. X-raydiffraction analysis shows that the films are highiy c-axis oriented. Auger electron spectroscopy depth profilingdemonstrates Ho diffusion into the Zr(Y)O_2 subetrate owing to the Ho subetitution for Y.
文摘为了验证采用金属单质靶与硫属化合物靶混合溅射法制备Cu_(2)Sn S_(3)(CTS)薄膜及太阳电池的可行性,在镀钼的钠钙玻璃上通过磁控溅射Sn和Cu S靶制备CTS预制层后,再经过低温合金化和高温硫化过程制备CTS薄膜,研究了硫化过程中不同升温速率对CTS薄膜表面形貌的影响。采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)及配属的能谱仪(EDS)、拉曼散射(Raman)对薄膜的晶体结构、表面和截面形貌、薄膜组分、物相进行表征分析,利用紫外-可见光光度计和霍尔测试系统表征了薄膜的光电特性。在硫化升温速率为35℃/min的条件下,获得了表面致密平整且纯相的单斜结构CTS薄膜,并用CTS薄膜制备了太阳电池。随后在标准测试条件(AM1.5,100 m W/cm^2,300 K)下采用KEITHLEY的2400数字源表测试了电池的I-V特性,其开路电压为299 m V,短路电流密度为16.6 m A/cm^2,光电转换效率为1.18%。结果表明,采用磁控溅射金属单质靶Sn与硫属化合物靶Cu S有望制备出高效CTS薄膜太阳电池。
基金Projects(51204214,51272292,51222403)supported by the National Natural Science Foundation of China
文摘The Cu_(2)ZnSnS_(4)thin film was prepared by a facile solution method without vacuum environment and toxic substance.The formation mechanism of the film was studied by transmission electron microscopy(TEM),X-ray diffraction(XRD),scanning electron microscopy(SEM),energy dispersive X-ray spectroscopy(EDS),and Raman scattering measurements.Through cyclic voltammetry and photo-electricity tests,the electrocatalytic activity of the prepared film as the counter electrode of dye-sensitizedsolar cell was also studied.The results show that the mixed precursor solution mainly consists of Cu2SnS3 nanoparticles and Zn ions.After 550°C annealing process on the precursor film prepared from the mixed solution,Cu_(2)ZnSnS_(4)thin film is obtained.Besides,itis found that the prepared Cu_(2)ZnSnS_(4)thin film has the electrocatalytic activity toward the redox reaction of I3?/I?and the dye-sensitized solar cell with the prepared Cu_(2)ZnSnS_(4)thin film as the counter electrode achieves the efficiency of 1.09%.
文摘YBa2Cu3O7-x(YBCO) thin film has been epitaxially deposited on (1120) sapphire with Y2O3-stabilized ZrO2 (YSZ) buffer layer and shown a high critical current density Jc of 1. 6×106A/cm2 at 77 K in zero magnetic field. The orientation relationship of the multilayer film superconductor has been determined. The(001) plane of the YBCO film is parallel to the(100) surface of the YSZ intermediate layer. YSZ buffer layer with(100) preferred orientation is about 20 nm thick and contains element Ba, due to out-diffusion of Ba from YBCO layer. The(100) preferred orientation of YSZ buffer permits the growth of high quality YBCO thin film. Y2BaCuO5 precipitates with small size distribute uniformly in the YBCO thin film and it is favourable to raise critical current density Jc.
文摘Cu_(2)ZnSnS_(4)薄膜因其元素地壳含量丰富、无毒且具有优异的光电性能,受到研究者的广泛关注。本文基于纳米墨水法用Cd部分取代Zn制成了Cu_(2)(Cd x Zn_(1-x))SnS_(4)(CCZTS)薄膜,研究退火时间和后退火温度对薄膜及其太阳电池性能的影响。研究结果表明,所制备的薄膜为CCZTS相,无其他杂相,薄膜表面平整且致密,结晶性较好。随着退火时间增加,薄膜的晶粒尺寸有所增大,薄膜太阳电池的pn结质量得到提升,其性能也随之提高。通过对薄膜太阳电池进行后退火处理,分析了吸收层的元素扩散对电池性能的影响,在Cd元素形成梯度分布时,电池性能有所提高。随着后退火温度的增加,其电池性能和pn结质量呈现先提高后下降的趋势。经后退火300℃处理后,电池转换效率最佳,为3.13%。
基金the UCLA California NanoSystem Institute(CNSI)Noble Family Innovation Fund for material preparationpartial support from the National Science Foundation through grant number 2329192 for transport studies and analysis.
文摘Copper-doped Bi_(2)Se_(3)(Cu_(x)Bi_(2)Se_(3))is of considerable interest for tailoring its electronic properties and inducing exotic charge correlations while retaining the unique Dirac surface states.However,the copper dopants in Cu_(x)Bi_(2)Se_(3) display complex electronic behaviors and may function as either electron donors or acceptors depending on their concentration and atomic sites within the Bi_(2)Se_(3) crystal lattice.Thus,a precise understanding and control of the doping concentration and sites is of both fundamental and practical significance.Herein,we report a solution-based one-pot synthesis of Cu_(x)Bi_(2)Se_(3) nanoplates with systematically tunable Cu doping concentrations and doping sites.Our studies reveal a gradual evolution from intercalative sites to substitutional sites with increasing Cu concentrations.The Cu atoms at intercalative sites function as electron donors while those at the substitutional sites function as electron acceptors,producing distinct effects on the electronic properties of the resulting materials.We further show that Cu_(0.18)Bi_(2)Se_(3) exhibits superconducting behavior,which is not present in Bi_(2)Se_(3),highlighting the essential role of Cu doping in tailoring exotic quantum properties.This study establishes an efficient methodology for precise synthesis of Cu_(x)Bi_(2)Se_(3) with tailored doping concentrations,doping sites,and electronic properties.
