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
Despite the existence of plentiful photocatalyst heterojunctions,their separation efficiency and charge flow precision remain low on account of lacking interfacial modulation.Herein,through a defect-induced heterojunc...Despite the existence of plentiful photocatalyst heterojunctions,their separation efficiency and charge flow precision remain low on account of lacking interfacial modulation.Herein,through a defect-induced heterojunction constructing strategy,Ni4Mo alloys were in-situ grown on the unsaturated coordinated sulfur atoms of sulfur vacancies-rich ZCS(Sv-ZCS)via interfacial Ni-S covalent bonds.The experimental and theoretical results reveal that these unsaturated sulfur atoms induced by sulfur vacancies vastly facilitate to anchor more Ni-Mo nanoparticles and form abundant Ni-S covalent bonds,meanwhile,these sulfur vacancies could form dual internal electric field(IEF)and work with Ni-S covalent bonds as“Electron Bridge”to further accelerate photoelectrons transfer,as well as promote the activation of water molecules and the desorption of hydrogen proton.Accordingly,the optimized Ni_(4)Mo/Sv-ZCS composite achieves an improved photocatalytic hydrogen evolution(PHE)rate of 94.69 mmol h^(-1)g^(-1)without an evident decrease after 6 cycles of photocatalytic tests,which is 21.2 and 1.94 times higher than those of Pt/ZCS and Ni_(4)Mo/ZCS,respectively.This tactic opens a new way for optimizing Zn_(x)Cd_(1-x)S-based heterojunctions by constructing sulfur vacancies and covalent bonds as“Electron Bridge”to enhance the activity of PHE.展开更多
The crystal structure,Raman vibration,chemical bond characteristics,and microwave dielectric properties of Zn_(1-x)Cu_(x)WO_(4)(x=0-0.15)ceramics prepared by a solid-state reaction were investigated by XRD refinement,...The crystal structure,Raman vibration,chemical bond characteristics,and microwave dielectric properties of Zn_(1-x)Cu_(x)WO_(4)(x=0-0.15)ceramics prepared by a solid-state reaction were investigated by XRD refinement,Raman spectroscopy,P-V-L theory and XPS.According to the P-V-L theory,the properties of the W-O bond are stronger than those of the Zn-O bond,which makes a major contribution to the dielectric properties.The relative permittivity is mainly affected by the average bond ionicity,and the variations in the dielectric loss and tf are mainly attributed to the lattice energy and bond energy.XPS shows that the presence of Cut could produce oxygen vacancy defects,increasing the dielectric loss.Additionally,Raman spectra show that the increasing molecular polarizability causes the Raman shift to move to a low wavenumber,and the changes in Raman intensity and FWHM lead to a decrease in the degree of short-range ordering.Particularly,Zn_(0.97)Cu_(0.03)WO_(4) ceramics sintered at 925℃ showed satisfactory properties(εr=14.20,tanδ=1.473×10^(-4) at 9.087 GHz,and tf=-40 ppm/℃),which can potentially be applied to LTCC technology and indicate that Cu substitution can not only reduce the sintering temperature,but also optimize the dielectric properties.展开更多
The bond,vibration and microwave dielectric characteristics of Zn_(1- x)(Li_(0.5)Bi_(0.5))_(x)WO_(4)(x=0-0.12)ce-ramics were investigated by XRD refinement,Raman and FT-IR spectroscopy and complex bond valence theory....The bond,vibration and microwave dielectric characteristics of Zn_(1- x)(Li_(0.5)Bi_(0.5))_(x)WO_(4)(x=0-0.12)ce-ramics were investigated by XRD refinement,Raman and FT-IR spectroscopy and complex bond valence theory.The results showed that proper substitution of(Li_(0.5)Bi_(0.5))2þcan improve the sintering charac-teristics and microwave dielectric properties of ZnWO_(4).The increase of Q×f value was mainly attributed to dense and uniform microstructure,and the subsequent decrease resulted from the deterioration of structural stability and relative density.According to the complex bond valence theory,the chemical bond characteristics of ZnWO_(4) and Bi_(2)WO_(6) played an important role in the dielectric properties of the samples.Additionally,the samples(x=0.02)sintered at 900℃ showed satisfactory properties:ε_(r)=15.332,Q×f=35,762 GHz,and t_(f)=-65 ppm/℃,making it a potential candidate material for LTCC applications.展开更多
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supported by the National Natural Science Foundation of China under Grant(51871078 and 52071119)the Fundamental Research Funds for the Central Universities(HIT.OCEF.2021025)Open Project of State Key Laboratory of Urban Water Resource and Environment,Harbin Institute of Technology(ES202211)。
文摘Despite the existence of plentiful photocatalyst heterojunctions,their separation efficiency and charge flow precision remain low on account of lacking interfacial modulation.Herein,through a defect-induced heterojunction constructing strategy,Ni4Mo alloys were in-situ grown on the unsaturated coordinated sulfur atoms of sulfur vacancies-rich ZCS(Sv-ZCS)via interfacial Ni-S covalent bonds.The experimental and theoretical results reveal that these unsaturated sulfur atoms induced by sulfur vacancies vastly facilitate to anchor more Ni-Mo nanoparticles and form abundant Ni-S covalent bonds,meanwhile,these sulfur vacancies could form dual internal electric field(IEF)and work with Ni-S covalent bonds as“Electron Bridge”to further accelerate photoelectrons transfer,as well as promote the activation of water molecules and the desorption of hydrogen proton.Accordingly,the optimized Ni_(4)Mo/Sv-ZCS composite achieves an improved photocatalytic hydrogen evolution(PHE)rate of 94.69 mmol h^(-1)g^(-1)without an evident decrease after 6 cycles of photocatalytic tests,which is 21.2 and 1.94 times higher than those of Pt/ZCS and Ni_(4)Mo/ZCS,respectively.This tactic opens a new way for optimizing Zn_(x)Cd_(1-x)S-based heterojunctions by constructing sulfur vacancies and covalent bonds as“Electron Bridge”to enhance the activity of PHE.
基金This work was supported by the National Natural Science Foundation of China under Grant Nos.61771104,U1809215 and 62071106.
文摘The crystal structure,Raman vibration,chemical bond characteristics,and microwave dielectric properties of Zn_(1-x)Cu_(x)WO_(4)(x=0-0.15)ceramics prepared by a solid-state reaction were investigated by XRD refinement,Raman spectroscopy,P-V-L theory and XPS.According to the P-V-L theory,the properties of the W-O bond are stronger than those of the Zn-O bond,which makes a major contribution to the dielectric properties.The relative permittivity is mainly affected by the average bond ionicity,and the variations in the dielectric loss and tf are mainly attributed to the lattice energy and bond energy.XPS shows that the presence of Cut could produce oxygen vacancy defects,increasing the dielectric loss.Additionally,Raman spectra show that the increasing molecular polarizability causes the Raman shift to move to a low wavenumber,and the changes in Raman intensity and FWHM lead to a decrease in the degree of short-range ordering.Particularly,Zn_(0.97)Cu_(0.03)WO_(4) ceramics sintered at 925℃ showed satisfactory properties(εr=14.20,tanδ=1.473×10^(-4) at 9.087 GHz,and tf=-40 ppm/℃),which can potentially be applied to LTCC technology and indicate that Cu substitution can not only reduce the sintering temperature,but also optimize the dielectric properties.
基金This work was supported by the National Natural Science Foundation of China under Grant Nos 62071106,U1809215 and 61771104Key R&D projects in Sichuan Province under Grant No.21ZDYF3857.
文摘The bond,vibration and microwave dielectric characteristics of Zn_(1- x)(Li_(0.5)Bi_(0.5))_(x)WO_(4)(x=0-0.12)ce-ramics were investigated by XRD refinement,Raman and FT-IR spectroscopy and complex bond valence theory.The results showed that proper substitution of(Li_(0.5)Bi_(0.5))2þcan improve the sintering charac-teristics and microwave dielectric properties of ZnWO_(4).The increase of Q×f value was mainly attributed to dense and uniform microstructure,and the subsequent decrease resulted from the deterioration of structural stability and relative density.According to the complex bond valence theory,the chemical bond characteristics of ZnWO_(4) and Bi_(2)WO_(6) played an important role in the dielectric properties of the samples.Additionally,the samples(x=0.02)sintered at 900℃ showed satisfactory properties:ε_(r)=15.332,Q×f=35,762 GHz,and t_(f)=-65 ppm/℃,making it a potential candidate material for LTCC applications.
