The rare earth Pr doped Ca1-xPrxMnO3 （x=0, 0.06, 0.08, 0.1, 0.12, and 0.14） compound bulk samples were prepared to study the effect of Pr doping on thermoelectric transport properties of CaMnO3 compound system. The ...The rare earth Pr doped Ca1-xPrxMnO3 （x=0, 0.06, 0.08, 0.1, 0.12, and 0.14） compound bulk samples were prepared to study the effect of Pr doping on thermoelectric transport properties of CaMnO3 compound system. The doped samples exhibited sin-gle phase composition within the experimental doping range, with condensed bulk microstructure and small porosities. The electrical resistivity was remarkably reduced for doped samples, on account of the enhanced carrier concentration;the absolute value of See-beck coefficient was deteriorated mainly due to enhanced electron carrier concentration. The electrical performances of the doped samples reflected by resistivity and Seebeck coefficient fluctuations were optimistically tuned, with an optimized power factor value of 0.342 mW/（m·K2） at 873 K for x=0.08 sample, which was very much higher comparing with that of the un-doped sample. The lattice thermal conduction was really confined, leading to distinctly repressed total thermal conductivity. The thermoelectric per-formance was noticeably improved by Pr doping and the dimensionless figure of merit ZT for the Ca0.92Pr0.08MnO3 compound was favorably optimized with the maximum value 0.16 at 873 K.展开更多
通过固相法制备了掺杂Pr的锂离子电池正极材料Li[Ni0.5Co0.2Mn0.3](1-x)PrxO2(x=0、0.01、0.02、0.03和0.05)。用XRD、SEM、充放电测试、循环伏安测试等研究Pr掺杂对材料结构及电化学性能的影响。适量的掺杂不会改变材料的晶体类型,还...通过固相法制备了掺杂Pr的锂离子电池正极材料Li[Ni0.5Co0.2Mn0.3](1-x)PrxO2(x=0、0.01、0.02、0.03和0.05)。用XRD、SEM、充放电测试、循环伏安测试等研究Pr掺杂对材料结构及电化学性能的影响。适量的掺杂不会改变材料的晶体类型,还能减轻阳离子混排,稳定层状结构。在0.1 C(20 m A/g)下,x=0.02样品的首次放电比容量为186.9 m Ah/g,在5.0 C下循环100次后,容量保持率高达94.9%。展开更多
Praseodymium（III） doped CeF3, CeF3：Gd, LaF3, GdF3 and YF3 inorganic fluorides were precipitated in an aqueous, sur- factant-free solution, using NH4F as a source of fluoride ions. The as-prepared products were subj...Praseodymium（III） doped CeF3, CeF3：Gd, LaF3, GdF3 and YF3 inorganic fluorides were precipitated in an aqueous, sur- factant-free solution, using NH4F as a source of fluoride ions. The as-prepared products were subjected to a hydrothermal treatment, which led to the formation of crystalline nanoluminophores, composed of spherical （30 nm） and elongated （40-200 nm） nanos- tructures. Due to the presence of Pr3＋ ions, the synthesized nanomaterials showed yellow luminescence under a blue light irradiation. The nanoluminophore based on the YF3 host revealed the most promising spectroscopic properties, i.e., bright and intensive emission, hence it was investigated in detail. The photophysical properties of the nanomaterials obtained were studied by powder X-ray diffrac- tion （XRD）, transmission electron microscopy （TEM） and spectrofluorometry, i.e., measurements of excitation/emission spectra and luminescence decay curves.展开更多
Pr3＋ doped ZnO quantum dots （QDs） were successfully synthesized by sol-gel process. X-ray diffraction （XRD） and X-ray Phtoelectron spectroscopy （XPS） were used to analyze the microstructure variation of ZnO QDs...Pr3＋ doped ZnO quantum dots （QDs） were successfully synthesized by sol-gel process. X-ray diffraction （XRD） and X-ray Phtoelectron spectroscopy （XPS） were used to analyze the microstructure variation of ZnO QDs and the chemical environment of Pr3＋ with increasing Pr3＋ doping concentrations. Most of Pr3＋ ions distribute on the surface ofZnO QDs while a few of them penetrate into the ZnO lattice to substitute Zn2＋ which causes the lattice distortion and the change of the crystal size. With increasing concentration of Pr3＋ ions, the crystal size of ZnO QDs firstly increases and then decreases meanwhile the amorphization gradually increases. New Pr-O-Zn bonds formed after Pr3＋ doping and Pr3＋ ions have at least two chemical bonding environments： one is Pr-O-Zn bond and the other is Pr-O bond surrounded by oxygen vacancies.展开更多
基金Project supported by National Natural Science Foundation of China(50801002)Beijing Municipal Natural Science Foundation(2112007)Basic and Advanced Technology Research Project of Henan Province(132300410071)
文摘The rare earth Pr doped Ca1-xPrxMnO3 （x=0, 0.06, 0.08, 0.1, 0.12, and 0.14） compound bulk samples were prepared to study the effect of Pr doping on thermoelectric transport properties of CaMnO3 compound system. The doped samples exhibited sin-gle phase composition within the experimental doping range, with condensed bulk microstructure and small porosities. The electrical resistivity was remarkably reduced for doped samples, on account of the enhanced carrier concentration;the absolute value of See-beck coefficient was deteriorated mainly due to enhanced electron carrier concentration. The electrical performances of the doped samples reflected by resistivity and Seebeck coefficient fluctuations were optimistically tuned, with an optimized power factor value of 0.342 mW/（m·K2） at 873 K for x=0.08 sample, which was very much higher comparing with that of the un-doped sample. The lattice thermal conduction was really confined, leading to distinctly repressed total thermal conductivity. The thermoelectric per-formance was noticeably improved by Pr doping and the dimensionless figure of merit ZT for the Ca0.92Pr0.08MnO3 compound was favorably optimized with the maximum value 0.16 at 873 K.
文摘通过固相法制备了掺杂Pr的锂离子电池正极材料Li[Ni0.5Co0.2Mn0.3](1-x)PrxO2(x=0、0.01、0.02、0.03和0.05)。用XRD、SEM、充放电测试、循环伏安测试等研究Pr掺杂对材料结构及电化学性能的影响。适量的掺杂不会改变材料的晶体类型,还能减轻阳离子混排,稳定层状结构。在0.1 C(20 m A/g)下,x=0.02样品的首次放电比容量为186.9 m Ah/g,在5.0 C下循环100次后,容量保持率高达94.9%。
基金Project supported by the Polish National Science Centre(2015/17/N/ST5/01947)
文摘Praseodymium（III） doped CeF3, CeF3：Gd, LaF3, GdF3 and YF3 inorganic fluorides were precipitated in an aqueous, sur- factant-free solution, using NH4F as a source of fluoride ions. The as-prepared products were subjected to a hydrothermal treatment, which led to the formation of crystalline nanoluminophores, composed of spherical （30 nm） and elongated （40-200 nm） nanos- tructures. Due to the presence of Pr3＋ ions, the synthesized nanomaterials showed yellow luminescence under a blue light irradiation. The nanoluminophore based on the YF3 host revealed the most promising spectroscopic properties, i.e., bright and intensive emission, hence it was investigated in detail. The photophysical properties of the nanomaterials obtained were studied by powder X-ray diffrac- tion （XRD）, transmission electron microscopy （TEM） and spectrofluorometry, i.e., measurements of excitation/emission spectra and luminescence decay curves.
基金Funded by the Science and Technology Planning Project of Wuhan City(No.2013010501010135)the Science and Technology Planning Project of Hubei Province(Nos.2013BAA095,2014BAA136)National Natural Science Foundation of China(No.51372179)
文摘Pr3＋ doped ZnO quantum dots （QDs） were successfully synthesized by sol-gel process. X-ray diffraction （XRD） and X-ray Phtoelectron spectroscopy （XPS） were used to analyze the microstructure variation of ZnO QDs and the chemical environment of Pr3＋ with increasing Pr3＋ doping concentrations. Most of Pr3＋ ions distribute on the surface ofZnO QDs while a few of them penetrate into the ZnO lattice to substitute Zn2＋ which causes the lattice distortion and the change of the crystal size. With increasing concentration of Pr3＋ ions, the crystal size of ZnO QDs firstly increases and then decreases meanwhile the amorphization gradually increases. New Pr-O-Zn bonds formed after Pr3＋ doping and Pr3＋ ions have at least two chemical bonding environments： one is Pr-O-Zn bond and the other is Pr-O bond surrounded by oxygen vacancies.
