For obtaining pure phase T12Ba2Ca2Cu3O10 （T1-2223） films with good superconducting properties, the growth technique is improved by dc magnetron sputtering and a triple post-annealing process. The triple post-anneali...For obtaining pure phase T12Ba2Ca2Cu3O10 （T1-2223） films with good superconducting properties, the growth technique is improved by dc magnetron sputtering and a triple post-annealing process. The triple post-annealing process comprises annealing twice in argon and once in oxygen at different temperatures. In the first low-temperature annealing phase in argon, T12Ba2CaCu2O8 （T1-2212） is obtained to effectively minimize evaporation in the next step. With the increase of temperature in the second annealing stage in argon, the previously prepared T1-2212 inter-phase is converted into T1-2223 phase. An additional annealing in oxygen is also adopted to improve the properties of T1-2223 films, each containing an optimal oxygen content value. The results of X-ray diffraction （XRD） θ-2θ scans, 09 scans and rotational φ scans show that each of the T1-2223 films has a high phase purity and an epitaxial structure. Smooth films are observed by scanning electron microscopy （SEM）. The critical temperatures Tc of the films are measured to be about 120 K and the critical current densities Jc can reach 4.0 MA/cm2 at 77 K at self field.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
Rare earth(RE)-doped TiO_(2)thin films possess important applications in modern optoelectronic devices.However,the high annealing temperature requirement remains a critical restriction in device fabrications.In this w...Rare earth(RE)-doped TiO_(2)thin films possess important applications in modern optoelectronic devices.However,the high annealing temperature requirement remains a critical restriction in device fabrications.In this work,TiO_(2)thin films doped with trivalent europium(Eu^(3+))ions were fabricated by a convenient sol-gel approach and subsequent annealing treatment.Interestingly,it is found that the optimal post-annealing temperature of TiO_(2):Eu^(3+)thin film is dramatically reduced from 800 to 300℃by incorporating 10 at%Sn^(4+)into the sol precursor.The Sn-incorporated film annealed at 300℃shows a 4-fold enhancement in photoluminescence(PL)intensity related to Eu^(3+)ions to the optimized Sn-free film.Systematic analysis reveals that this enhancement is attributed to Sn element promoting the crystallization of both anatase TiO_(2)and rutile SnO_(2)clusters at 300℃,which provides sufficient SnO_(2)/TiO_(2)crystal boundary facilitating Eu^(3+)to occupy and sensitized by SnO_(2)crystals.These results provide valuable insights into fabricating highly luminescent RE-doped TiO_(2)thin films with low annealing temperature requirement,which is essential for designing optoelectronic devices based on RE materials more freely in the future.展开更多
Enhancement of post-annealing stability in Co/ Ni multilayers with perpendicular magnetic anisotropy （PMA） was obtained by inserting Au layers into Ni/Co interfaces. After annealing at 350 ℃, the effective mag- net...Enhancement of post-annealing stability in Co/ Ni multilayers with perpendicular magnetic anisotropy （PMA） was obtained by inserting Au layers into Ni/Co interfaces. After annealing at 350 ℃, the effective mag- netic anisotropy density （Kef0 for Ta（3）/Pt（2）/[Co（0.3）/ Ni（0.6）/Au（0.3）]× 3/Co（0.3）/Pt（1）/Ta（3） （in nm） keeps at 0.48 × 105 J·m^-3. Scanning transmission electron micro- scopy-high-angle annular dark field （STEM-HAADF） analysis shows that the diffusion between Ni and Co layers is obstructed by the Au insertion layers among them, which is responsible for the post-annealing stability enhancement of the multilayers. Multilayers with Pt insertion layers were also investigated as reference samples in this work. Com- pared with Pt-layer-inserted Co/Ni multilayers, the Au insertion layers are found to bring seldom interfacial PMA to the multilayers, making it competitive in being employed to enhance the post-annealing stability of PMA Co/Ni multilayers which are used for magnetic random access memory devices （MRAM）.展开更多
A new improved two-step method in fabricating Tl_(2)Ba_(2)CaCu_(2)O_(8)(Tl-2212)thin films is presented in this paper.In the first process of dc magnetron sputtering,the thallium content in the precursor film is large...A new improved two-step method in fabricating Tl_(2)Ba_(2)CaCu_(2)O_(8)(Tl-2212)thin films is presented in this paper.In the first process of dc magnetron sputtering,the thallium content in the precursor film is largely increased by adjusting the ratio of thallium in the sputtering targets.After the second annealing process in the absence of additional thallium pellets or powder source,high-quality Tl-2212 thin films can be obtained.The proper content of thallium in the precursor film provides a relatively stable atmosphere to guarantee the growth of Tl-2212 film.This method avoids the repeated production of the thallium pellets in the post-annealing process,the repeatability and controllability of the experiment are greatly improved.X-ray diffraction(XRD)scans show that all of the sharp peaks of the sample films can be assigned to the(00 l)peaks of Tl-2212 phase.The highest superconducting critical temperature(T_(c))of the films is 105 K and the critical current density(J_(c))can achieve 1.93 MA/cm^(2) in zero magnetic field at 77 K for a 600 nm film.展开更多
We develop a heterojunction-based Schottky solar cell consisting of n-type GaN and PEDOT：PSS and also investigate the effect of annealing on the performance of the solar cell. The results show that the open circuit v...We develop a heterojunction-based Schottky solar cell consisting of n-type GaN and PEDOT：PSS and also investigate the effect of annealing on the performance of the solar cell. The results show that the open circuit voltage （Voc） increases from 0.54 V to 0.56 V, 0.71 V and 0.82 eV while decreases to 0.69 eV after annealing at 100 ℃, 130 ℃, 160 ℃, and 200 ℃, respectively, which can be ascribed to the change of barrier height of PEDOT：PSS/GaN Schottky contact induced by variation of the work function of the PEDOT：PSS. Furthermore, the conductivity and surface roughness measurements of the PEDOT：PSS indicate that annealing can increase the grain size and improve the connectivity between PEDOT and PSS particles, and cause thermal degradation at the same time, which leads to the rise in short-circuit current density （ISC） up to 160 ℃ and the dropoff in ISC after annealing at 200 ℃.展开更多
The effect of substrate temperature on the structure and magnetic properties of CoPt/AlN multilayer films has been investigated.The crystallinity of CoPt has been improved with increasing substrate temperature from ro...The effect of substrate temperature on the structure and magnetic properties of CoPt/AlN multilayer films has been investigated.The crystallinity of CoPt has been improved with increasing substrate temperature from room temperature to 400 ℃.After post-annealing process,L1_0 CoPt structure transformation has also been promoted.However,since the easy magnetic axis of L1_0 CoPt is in[001]orientation,the promotion of L1_0 CoPt transformation causes the change of easy magnetic axis in（111） textured CoPt layers,which impairs the perpendicular magnetic anisotropy.The optimum substrate temperature should be room temperature to obtain the strongest perpendicular magnetic anisotropy according to the results of the present work.展开更多
Isotropic Sm-Co nanoparticle powders with high coercivity were prepared by high-energy ball milling followed by optimal annealing at different temperatures.The covercivity increased monotonically with increasing of th...Isotropic Sm-Co nanoparticle powders with high coercivity were prepared by high-energy ball milling followed by optimal annealing at different temperatures.The covercivity increased monotonically with increasing of the annealing temperature and a highest coercivity of 31.2 kOe was obtained.The sample with an optimal energy product of 17.0 MGOe still had a coercivity of 18.2 kOe.The evolution of phase,particle size,mechanism of coercivity and other related magnetic properties were analyzed.The excellent performance is attributed to nanoscale size grains below 15 nm and good exchange coupling between nanoparticles.展开更多
Ag_(3)PO_(4) as a novel photoanode material,despite its arguably highest photoactivity,suffers for its poor light absorption and stability for photoelectrochemical(PEC)water oxidation.In this work,4.54.5 cm^(2) Ag_(3)...Ag_(3)PO_(4) as a novel photoanode material,despite its arguably highest photoactivity,suffers for its poor light absorption and stability for photoelectrochemical(PEC)water oxidation.In this work,4.54.5 cm^(2) Ag_(3)PO_(4) microcrystalline films are grown via a room-temperature solution process,and vacuum annealing is proposed to solve the stability and light absorption issues.It is found that the major process below 400℃ of vacuum annealing is the|Recovery|process for Ag_(3)PO_(4) microcrystals,when lattice defects and Ag0 surface species get reduced.Next,|Recrystallization|stage occurs at>40℃.The recovery of native defects of silver vacancies,with both density functional theory calculation and experimental results,could simultaneously improve the light absorption and catalytic activity of Ag_(3)PO_(4).The 400℃-annealed Ag_(3)PO_(4) photoanode,with enhanced light harvesting and crystal quality,exhibits 88% increase in(Jlight-Jdark)value(1.94 mA cm^(-2))than non-annealed photoanode(1.03 mA cm^(-2)).Moreover,it retains>99% current density after a 4000-s stability test.These results suggest that vacuum annealing can substantially improve the PEC performance of Ag_(3)PO_(4) microcrystalline film photoanodes due to mitigated effects of native defects,improved light harvesting,and inhibited Ag_(3)PO_(4) decomposition during water oxidation reaction.展开更多
TiNb2O7 anode materials(TNO)have unique potential for applications in Li-ion capacitors(LICs)due to their high specific capacity of ca.280 mA h g^-1 over a wide anodic Li-insertion potential window.However,their highr...TiNb2O7 anode materials(TNO)have unique potential for applications in Li-ion capacitors(LICs)due to their high specific capacity of ca.280 mA h g^-1 over a wide anodic Li-insertion potential window.However,their highrate capability is limited by their poor electronic and ionic conductivity.In particular,studies on TNO for LICs are lacking and that for flexible LICs have not yet been reported.Herein,a unique TNO porous electrode with cross-linked nanorods tailored by post-annealing and its application in flexible LICs are reported.This binder-free TNO anode exhibits superior rate performance(~66.3%capacity retention as the rate increases from 1 to 40 C),which is ascribed to the greatly shortened ion-diffusion length in TNO nanorods,facile electrolyte penetration and fast electron transport along the continuous single-crystalline nanorod network.Furthermore,the TNO anode shows an excellent cycling stability up to 2000 cycles and good flexibility(no capacity loss after continuous bending for 500 times).Model flexible LIC assembled with the TNO anode and activated carbon cathode exhibits increased gravimetric and volumetric energy/power densities(~100.6 W h kg^-1/4108.8 W kg^-1;10.7 mW h cm^-3/419.3 mW cm^-3),more superior to previously reported hybrid supercapacitors.The device also efficiently powers an LED light upon 180°bending.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.51002081 and 61176119)
文摘For obtaining pure phase T12Ba2Ca2Cu3O10 （T1-2223） films with good superconducting properties, the growth technique is improved by dc magnetron sputtering and a triple post-annealing process. The triple post-annealing process comprises annealing twice in argon and once in oxygen at different temperatures. In the first low-temperature annealing phase in argon, T12Ba2CaCu2O8 （T1-2212） is obtained to effectively minimize evaporation in the next step. With the increase of temperature in the second annealing stage in argon, the previously prepared T1-2212 inter-phase is converted into T1-2223 phase. An additional annealing in oxygen is also adopted to improve the properties of T1-2223 films, each containing an optimal oxygen content value. The results of X-ray diffraction （XRD） θ-2θ scans, 09 scans and rotational φ scans show that each of the T1-2223 films has a high phase purity and an epitaxial structure. Smooth films are observed by scanning electron microscopy （SEM）. The critical temperatures Tc of the films are measured to be about 120 K and the critical current densities Jc can reach 4.0 MA/cm2 at 77 K at self field.
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 National Natural Science Foundation of China(61504030,11704081)Natural Science Foundation of Guangxi Province(2020GXNSFAA238043,2020GXNSFAA297182,2017GXNSFGA198005)the Special Fund for Guangxi Distinguished Professors(Bagui Yingcai&Bagui Xuezhe)2017AD22006。
文摘Rare earth(RE)-doped TiO_(2)thin films possess important applications in modern optoelectronic devices.However,the high annealing temperature requirement remains a critical restriction in device fabrications.In this work,TiO_(2)thin films doped with trivalent europium(Eu^(3+))ions were fabricated by a convenient sol-gel approach and subsequent annealing treatment.Interestingly,it is found that the optimal post-annealing temperature of TiO_(2):Eu^(3+)thin film is dramatically reduced from 800 to 300℃by incorporating 10 at%Sn^(4+)into the sol precursor.The Sn-incorporated film annealed at 300℃shows a 4-fold enhancement in photoluminescence(PL)intensity related to Eu^(3+)ions to the optimized Sn-free film.Systematic analysis reveals that this enhancement is attributed to Sn element promoting the crystallization of both anatase TiO_(2)and rutile SnO_(2)clusters at 300℃,which provides sufficient SnO_(2)/TiO_(2)crystal boundary facilitating Eu^(3+)to occupy and sensitized by SnO_(2)crystals.These results provide valuable insights into fabricating highly luminescent RE-doped TiO_(2)thin films with low annealing temperature requirement,which is essential for designing optoelectronic devices based on RE materials more freely in the future.
基金financially supported by the National Natural Science Foundation of China(Nos.51101012, 51271211,51331002,51371025,51371027,51471028 and 51571017)the National Key Scientific Research Projects of China(No. 2015CB921502)+1 种基金the Beijing Nova Program(No.Z141103001814039)the Fundamental Research Funds for the Central Universities(No. FRF-TP-14-002C1)
文摘Enhancement of post-annealing stability in Co/ Ni multilayers with perpendicular magnetic anisotropy （PMA） was obtained by inserting Au layers into Ni/Co interfaces. After annealing at 350 ℃, the effective mag- netic anisotropy density （Kef0 for Ta（3）/Pt（2）/[Co（0.3）/ Ni（0.6）/Au（0.3）]× 3/Co（0.3）/Pt（1）/Ta（3） （in nm） keeps at 0.48 × 105 J·m^-3. Scanning transmission electron micro- scopy-high-angle annular dark field （STEM-HAADF） analysis shows that the diffusion between Ni and Co layers is obstructed by the Au insertion layers among them, which is responsible for the post-annealing stability enhancement of the multilayers. Multilayers with Pt insertion layers were also investigated as reference samples in this work. Com- pared with Pt-layer-inserted Co/Ni multilayers, the Au insertion layers are found to bring seldom interfacial PMA to the multilayers, making it competitive in being employed to enhance the post-annealing stability of PMA Co/Ni multilayers which are used for magnetic random access memory devices （MRAM）.
基金Project supported by the National Natural Science Foundation of China(Grant No.51002081)the Fundamental Research Funds for the Central Universities,Chinathe Research Program of Application Foundation and Advanced Technology of Tianjin,China(Grant No.15JCQNJC01300)
文摘A new improved two-step method in fabricating Tl_(2)Ba_(2)CaCu_(2)O_(8)(Tl-2212)thin films is presented in this paper.In the first process of dc magnetron sputtering,the thallium content in the precursor film is largely increased by adjusting the ratio of thallium in the sputtering targets.After the second annealing process in the absence of additional thallium pellets or powder source,high-quality Tl-2212 thin films can be obtained.The proper content of thallium in the precursor film provides a relatively stable atmosphere to guarantee the growth of Tl-2212 film.This method avoids the repeated production of the thallium pellets in the post-annealing process,the repeatability and controllability of the experiment are greatly improved.X-ray diffraction(XRD)scans show that all of the sharp peaks of the sample films can be assigned to the(00 l)peaks of Tl-2212 phase.The highest superconducting critical temperature(T_(c))of the films is 105 K and the critical current density(J_(c))can achieve 1.93 MA/cm^(2) in zero magnetic field at 77 K for a 600 nm film.
基金supported by the Fundamental Research Funds for the Central Universities of Ministry of Education of China(Grant No.JB141104)
文摘We develop a heterojunction-based Schottky solar cell consisting of n-type GaN and PEDOT：PSS and also investigate the effect of annealing on the performance of the solar cell. The results show that the open circuit voltage （Voc） increases from 0.54 V to 0.56 V, 0.71 V and 0.82 eV while decreases to 0.69 eV after annealing at 100 ℃, 130 ℃, 160 ℃, and 200 ℃, respectively, which can be ascribed to the change of barrier height of PEDOT：PSS/GaN Schottky contact induced by variation of the work function of the PEDOT：PSS. Furthermore, the conductivity and surface roughness measurements of the PEDOT：PSS indicate that annealing can increase the grain size and improve the connectivity between PEDOT and PSS particles, and cause thermal degradation at the same time, which leads to the rise in short-circuit current density （ISC） up to 160 ℃ and the dropoff in ISC after annealing at 200 ℃.
文摘The effect of substrate temperature on the structure and magnetic properties of CoPt/AlN multilayer films has been investigated.The crystallinity of CoPt has been improved with increasing substrate temperature from room temperature to 400 ℃.After post-annealing process,L1_0 CoPt structure transformation has also been promoted.However,since the easy magnetic axis of L1_0 CoPt is in[001]orientation,the promotion of L1_0 CoPt transformation causes the change of easy magnetic axis in（111） textured CoPt layers,which impairs the perpendicular magnetic anisotropy.The optimum substrate temperature should be room temperature to obtain the strongest perpendicular magnetic anisotropy according to the results of the present work.
基金supported by the National Natural Science Foundation of China(Grant Nos.51771220,51771095,51422106)the Major Program of the Zhejiang Provincial Natural Science Foundation of China(Grant No.LD19E010001).
文摘Isotropic Sm-Co nanoparticle powders with high coercivity were prepared by high-energy ball milling followed by optimal annealing at different temperatures.The covercivity increased monotonically with increasing of the annealing temperature and a highest coercivity of 31.2 kOe was obtained.The sample with an optimal energy product of 17.0 MGOe still had a coercivity of 18.2 kOe.The evolution of phase,particle size,mechanism of coercivity and other related magnetic properties were analyzed.The excellent performance is attributed to nanoscale size grains below 15 nm and good exchange coupling between nanoparticles.
基金This work was supported by Fundamental Research Funds for the Central Universities of Ministry of Education of China(Southeast University)Core-to-Core Program(Advanced Research Networks Type A)of Japan Society for the Promotion of Science(JSPS)+4 种基金Q.Cao acknowledges the support of China Scholarship Council(No.201506100018)the START project of Japan Science and Technology Agency(JST)R.Che thanks the support of National Basic Research Program(973 Program No.2018YFA0209102)National Science Fund for Distinguished Young Scholars(No.51725101)National Natural Science Foundation of China(Nos.11727807,51672050,and 61790581)of China.
文摘Ag_(3)PO_(4) as a novel photoanode material,despite its arguably highest photoactivity,suffers for its poor light absorption and stability for photoelectrochemical(PEC)water oxidation.In this work,4.54.5 cm^(2) Ag_(3)PO_(4) microcrystalline films are grown via a room-temperature solution process,and vacuum annealing is proposed to solve the stability and light absorption issues.It is found that the major process below 400℃ of vacuum annealing is the|Recovery|process for Ag_(3)PO_(4) microcrystals,when lattice defects and Ag0 surface species get reduced.Next,|Recrystallization|stage occurs at>40℃.The recovery of native defects of silver vacancies,with both density functional theory calculation and experimental results,could simultaneously improve the light absorption and catalytic activity of Ag_(3)PO_(4).The 400℃-annealed Ag_(3)PO_(4) photoanode,with enhanced light harvesting and crystal quality,exhibits 88% increase in(Jlight-Jdark)value(1.94 mA cm^(-2))than non-annealed photoanode(1.03 mA cm^(-2)).Moreover,it retains>99% current density after a 4000-s stability test.These results suggest that vacuum annealing can substantially improve the PEC performance of Ag_(3)PO_(4) microcrystalline film photoanodes due to mitigated effects of native defects,improved light harvesting,and inhibited Ag_(3)PO_(4) decomposition during water oxidation reaction.
基金supported by the National Natural Science Foundation of China (51672205, 21673169 and 51972257)the National Key R&D Program of China (2016YFA0202602)the Natural Science Foundation of Hubei Province (2018CFB581)
文摘TiNb2O7 anode materials(TNO)have unique potential for applications in Li-ion capacitors(LICs)due to their high specific capacity of ca.280 mA h g^-1 over a wide anodic Li-insertion potential window.However,their highrate capability is limited by their poor electronic and ionic conductivity.In particular,studies on TNO for LICs are lacking and that for flexible LICs have not yet been reported.Herein,a unique TNO porous electrode with cross-linked nanorods tailored by post-annealing and its application in flexible LICs are reported.This binder-free TNO anode exhibits superior rate performance(~66.3%capacity retention as the rate increases from 1 to 40 C),which is ascribed to the greatly shortened ion-diffusion length in TNO nanorods,facile electrolyte penetration and fast electron transport along the continuous single-crystalline nanorod network.Furthermore,the TNO anode shows an excellent cycling stability up to 2000 cycles and good flexibility(no capacity loss after continuous bending for 500 times).Model flexible LIC assembled with the TNO anode and activated carbon cathode exhibits increased gravimetric and volumetric energy/power densities(~100.6 W h kg^-1/4108.8 W kg^-1;10.7 mW h cm^-3/419.3 mW cm^-3),more superior to previously reported hybrid supercapacitors.The device also efficiently powers an LED light upon 180°bending.
