NaCl-CsCl熔盐中Ce(Ⅲ)离子的阴极过程研究

以钨微盘为研究电极采用循环伏安法和方波伏安法研究了温度为873K的NaCl-CsCl熔盐中Ce3 离子的阴极行为.结果表明,摩尔比为1:2的NaCl-CsCl熔盐体系中Ce3 离子分两步还原,其电化学反应历程为:Ce3 e=Ce2 ,Ce2 2e-=Ce.进一步计算得到熔盐体系中Ce3 离子的扩散系数(D).     

Synthesis and characterization of Cu2ZnSnS4 from Cu2SnS3 and ZnS compounds

The Cu2ZnSnS4 (CZTS) powders are successfully synthesized by using ZnS and Cu2SnS3 as raw materials directly without any intermediate phase at 450 °C for 3 h in Ar atmosphere. The crystalline structure, morphology and optical properties of the CZTS powders are characterized by X-ray diffraction (XRD), Raman spectrum, field emission scanning electron microscopy (FESEM) and ultraviolet-visible (UV-vis) spectrophotometer, respectively. The results show that the band gap of the obtained CZTS is 1.53 eV. The CZTS film is fabricated by spin coating a mixture of CZTS powders and novolac resin with a weight percentage of 30%. The photoelectrical properties of such CZTS films are measured, and the results show an incident light density of 100 mW.cm-2 with the bias voltage of 0.40 V, and the photocurrent density can approach 9.80×10-5 A.cm2within 50 s, giving an on/off switching ratio of 1.64.     

Synthesis of CuInSe2 nanoparticles by phase transformation of In2Se3 via wet chemical process in low temperature

Chalcopyrite-type CulnSe2 nanoparticles are successfully prepared by using In2Se3 nanoparticles as a precursor reacted with copper chloride （CuCl） solution via a phase transformation process in low temperature. The reaction time is a key parameter. After the reaction time increasing from 0.5 h to 8 h, In2Se3 and CuCl react with each other gradually via phase transformation into CuInSe2 without any intermediate phase. The crystalline structure and morphology of the CuInSe2 nanoparticles are characterized by X-ray diffraction （XRD） and field emission scanning electron microscopy （FESEM）. The diameter of CuInSe2 nanoparticles with good dispersibility ranges from 10 nm to 20 nm. The band gap of the CulnSe2 nanoparticles is 1.04 eV calculated from the ultraviolet-visible （UV-VIS） spectrum.     

液氨中原位制备Si3N4-TiN纳米复合材料及表征

"提出了一种合成氮化钛/氮化硅(TiN/Si3N4)纳米复合材料的新方法．采用TiCl4和SiCl4作为原料,金属钠作为还原剂,以液氨为介质．在-45 ℃左右同时还原四氯化钛和四氯化硅,通过原位共沉淀获得TiN/Si3N4的纳米复合粉体．X射线衍射表明产物为非晶结构,副产物为氯化钠．产物粉末加热到1600 ℃晶化为TiN和ˉ-Si3N4．由于TiN的存在,混合粉末中的氮化硅晶化温度高于纯氮化硅的晶化温度．透射电镜照片显示粉末平均粒径在10~40 nm,扫描电镜照片表明钛、硅元素彼此均匀分布．在1500~1     

非化学计量金属间化合物DO3型Fe3Al热力学性质

用以CaF2单晶为固体电解质的电池电动势(EMF)法测定了720～850 K温度区间内(－)Pt|Ir|Al_0.85Sn_0.15,Na₃AlF₆|CaF₂|Al_xFe_1－x(x=0.23～0.33),Na₃AlF₆|Ir|Pt(＋)电池电动势,通过DO₃型Fe₃Al的粉末化以及选用富Al合金Al_0.85Sn_0.15作为参比电极,使电池反应较快地达到热力学平衡,EMF测量前后工作电极的X射线衍射分析证明没有化学变化发生.计算了DO₃型Fe₃Al非化学计量金属间化合物均相范围内组元Al的活度及Al的偏摩尔热力学函数ΔG_Al、ΔH_Al、ΔS_Al ,基于Gibbs-Duhem方程计算了DO₃型Fe₃Al中另一组元Fe的活度和偏摩尔Gibbs自由能.计算了750 K时DO₃型Fe₃Al相中Al的扩散热力学因子,在化学计量比成分(xAl=0.25)附近Fe₃Al相中Al扩散的热力学因子达到最大值.     

Effect of thickness on optoelectrical properties of Nb-doped indium tin oxide thin films deposited by RF magnetron sputtering

Niobium-doped indium tin oxide （ITO:Nb） thin films are prepared on glass substrates with various film thicknesses by radio frequency （RF） magnetron sputtering from one piece of ceramic target material. The effects of thickness （60-360 nm） on the structural, electrical and optical properties of ITO: Nb films are investigated by means of X-ray diffraction （XRD）, ultraviolet （UV）-visible spectroscopy, and electrical measurements. XRD patterns show the highly oriented （400） direction. The lowest resistivity of the films without any heat treatment is 3.1×10^-4 Ω·cm^-1, and the resistivity decreases with the increase of substrate temperature. The highest Hall mobility and carrier concentration are 17.6 N·S and 1.36×10²¹ cm^-3, respectively. Band gap energy of the films depends on substrate temperature, which varies from 3.48 eV to 3.62 eV.