共查询到19条相似文献,搜索用时 140 毫秒
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Well-crystallized LiNiO2 thin films were prepared directly on nickel substrates in LiOH solution by constant current electrochemical deposition technique at 95 ℃. The as-prepared LiNiO2 thin films were characterized by using XRD, SEM and XPS, and the results reveal that the as-prepared LiNiO2 thin films are dense and uniform in surface and show hexagonal structure. The influence of processing parameters such as reaction temperature, duration, electrical current density as well as the concentration of LiOH solution on the structure and morphologies of as-prepared LiNiO2 thin films were studied,and the preferable electrochemical processing conditions for preparing LiNiO2 thin films were suggested. 相似文献
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轰击离子能量对CNx薄膜中sp3型C-N键含量的影响 总被引:1,自引:0,他引:1
对磁控溅射生长在单晶Si(001)衬底上的CNx薄膜样品的化学键合及结构进行了研究,利用不同的衬底负偏压(Vh)来控制轰击衬底表面的入射离子能量,从而影响膜中的化学键合的状态.样品的FTIR,Ra-man和XPS分析结果表明,CNx薄膜中N原子分别与sp,sp2和sp3杂化状态的C原子结合,其中sp3型C-N键含量先随着衬底偏压(Vb)的升高而增加,并在偏压Vb=-50V时达到最大值,但随着Vb继续升高,sp3型C-N键含量减少,这表明CNx薄膜中,sp3型C-N键的含量与轰击离子的能量变化密切相关. 相似文献
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采用电泳沉积法, 在FTO/介孔TiO2薄膜上制备了介孔TiO2/单壁碳纳米管(SWCNTs)薄膜电极, 用Raman和SEM等手段对薄膜电极进行了表征. 结果表明, SWCNTs已沉积到介孔TiO2薄膜上. 分别用四羧基苯基卟啉(TCPP)和联吡啶钌化合物N719对其进行敏化, 并组装成太阳能电池. 研究结果表明, 与单纯的TiO2粒子膜相比, 介孔TiO2和SWCNTs的紧密结合可使得光生电子更容易传输, 光电转换效率显著提高. 相似文献
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Two ferrates, K2FeO4 and BaFeO4, had been prepared and characterized by XRD, IR and SEM. The electrochemical tests of the samples were carried out in the voltage range of 0.8~2.0 V and current density of 0.5~3.0 mA·cm-2. The results indicated that performance of Zn-BaFeO4 battery was superior to that of Zn-MnO2 and Zn-K2FeO4 batteries. Nanometer SrTiO3 prepared by Sol-gel methode with different ratio was added to the BaFeO4 cathode in order to improve the discharge performance. The discharge capacity of the BaFeO4 cathode was increased from 224 mAh·g-1 to 246 mAh·g-1 by addition of 5% nanometer SrTiO3. The reason of enhancing BaFeO4 electrochemical performance was discussed. 相似文献
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碳包覆LiFePO4的一步固相法制备及高温电化学性能 总被引:8,自引:0,他引:8
Carbon coated LiFePO4 cathode material was synthesized by one-step solid-state reaction and characterized by X-ray diffraction (XRD), field-emission-scanning electron microscope (FESEM). Electrochemical performances of the material as cathode in lithium-ion battery were investigated at medium and elevated temperature (30 and 55 ℃) by galvanostatic charge-discharge and A.C. impedance tests. The results show that carbon coated LiFePO4 powder exhibits a well-crystallized olivine structure and spherical morphology with an average particle size of about 500 nm. Galvanostatic charge-discharge tests show that the reversible discharge capacity at 1 C and 1.5 C rates was improved from 121 and 105 mAh·g-1 at 30 ℃ to 136 and 123 mAh·g-1 at 55℃, respectively, while the enhancement of high temperature on electrochemical performance is less obvious at a rate lower than 0.5 C. Impedance spectra analyses indicate that the cathode material has a remarkably higher lithium-ion diffusivity at 55 ℃ than that at 30 ℃, which improves the electrochemical performance at high temperature. 相似文献
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CoOx改性TiO2光催化剂的制备、优化及其光催化分解水析氢性能研究 总被引:4,自引:0,他引:4
利用热分解法制备了不同掺杂量的CoOx-TiO2系列光催化剂, 并优化了制备方法。在用XRD、TEM和XPS等技术对催化剂表征的基础上,探讨了乙醇作为电子给体时CoOx改性对P25-TiO2光催化分解水析氢性能的影响。本文还利用连续瞬态电流-时间响应和循环伏安法等电化学方法,考察了CoOx-TiO2改性系列光催化剂光照条件下电流响应强度、起始光电响应特性差别及光催化析氢电位变化等光电化学性能。光催化性能实验结果表明,适当掺杂CoOx(110~400 ℃焙烧时最佳掺杂量约为0.4wt% Co,500 ℃焙烧时最佳掺杂量约为0.6~0.8wt% Co)能够显著地提高TiO2析氢光催化性能,产氢速率提高2个数量级。另外在适当温度下的热处理,能够改善催化剂光催化性能(最佳处理温度为300~400 ℃)。光电化学性能评价结果表明,适当掺杂CoOx和适当温度下焙烧能在催化剂表面形成较多的析氢活性物种——含钴复合物,能有效增强催化剂光电流响应强度,并使得析氢光还原电位向有利于析氢方向位移。高含量掺杂CoOx会在催化剂表面形成某种碳化物物种,大量含钴复合物活性中心的出现会降低光吸收效率,增加TiO2表面光生电子-空穴复合率而使催化剂失去析氢光催化性能。 相似文献
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通过高温固相法制得尖晶石LiMn2O4,然后在通过简单易行的无水乙醇蒸干法包覆LaF3来修饰LiMn2O4。利用XRD,SEM来表征LaF3修饰的LiMn2O4的结构和形貌特征,并通过电化学测试研究LaF3修饰LiMn2O4的高温和常温下的电化学性能,另外结合电化学阻抗谱(EIS)和循环伏安(CV)考察表面修饰的锰酸锂的循环阻抗和循环可逆性。结果显示:经LaF3修饰过的LiMn2O4仍具有尖晶石结构,并且具有良好的电学性能。其中,以3wt%的修饰效果最好,常温循环100次和高温循环50次的循环保持率分别是91%和90%;而且,EIS和CV分别表明经LaF3修饰的LiMn2O4的电荷传递阻抗明显减小,其循环可逆性也明显提高。 相似文献
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利用恒电位电沉积法在以乙醇为溶剂的溶液中制备了铜铟镓硒(CIGS)薄膜.并采用扫描电子显微镜(SEM)、X射线能谱仪(EDS)、X射线衍射仪(XRD)和紫外-可见-近红外(UV-VIS-NIR)分光光度计分别对薄膜的形貌、成分、晶体结构和吸收特性进行了表征.结果表明在-1.6V(相对于饱和甘汞电极电位)工作电位下沉积的薄膜经450°C退火后能够形成形貌均匀致密、结晶性良好、带隙约为1.17eV的黄铜矿结构CuIn0.7Ga0.3Se2薄膜.实验过程中发现,以乙醇为溶剂可以有效避免在水溶液中出现的析氢现象,减小了沉积电位的限制. 相似文献
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LI Gao-ren TONG Ye-xiang ** LIU Guan-kun School of Chemistry Chemical Engineering Zhongshan University Guangzhou P. R. China 《高等学校化学研究》2003,19(4):499-503
IntroductionSemimetallic bismuth is a material exhibitinginteresting magnetoresistance( MR) characteristicand finite- size effect,whose electronic propertiesare fundamentally different from those of commonmetals due to the complex and highly anisotropicFermi surface[1] .Recently,Bi has attracted ourmuch attention for its applications involving fieldand current sensing due to its extremely high mag-netoresistance( MR) relative to those reported forGMR and CMR materials.The large MR of Bia… 相似文献
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LI Gao ren TONG Ye xiang ** LIU Guan kun School of Chemistry Chemical Engineering Zhongshan University Guangzhou P. R. China 《高等学校化学研究》2003,19(2):190-195
IntroductionAmorphous rare earth- transition metal alloys,which are generally ferrimagnetic,have been inten-sively studied because of their potential practicalapplication[1— 4] .They cover a wide range of satu-raion magnetisation,permeability,coercivity andmagnetostriction.Amorphous alloys in the form ofthin films show peculiar magnetic properties( per-pendicularanisotropy,large coercivity and compen-sation temperatures) which make them interestingmaterials for magnetooptical application[1] .… 相似文献
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使用射频磁控溅射方法在不同衬底温度下(ts=室温,350,500℃)于Si(001)衬底上沉积了CNx膜,并利用拉曼(Raman)光谱、傅里叶变换红外光谱(FTIR)及X射线衍射光电子能谱(XPS)对CNx膜的化学结合状态与温度的关系进行了研究。Raman光谱结果表明,随衬底温度(ts) 增加,D带向低频方向移动,G带向高频方向移动;它们的半高宽分别由375和150cm^-1减小至328和142cm^-1;ID/IG由3.76减小至2.88。FTIR谱中除无序D带(1400cm^-1)和石墨G带(1570cm^-1)外,还有-700cm^-1,~2210cm^-1(C=N),2330cm^-1(C-O)及3255-3351cm^-1(N-H)等峰。XPS测试结果表明:随衬底温度增加,N与C的物质的量比由0.49下降至0.38,sp^2(C-N)组分与sp^3(C-N)组分强度比呈增大趋势。低温(350℃)退火并未对CNx膜的化学结合状态产生较大影响;高温(900℃)退火样品则显示出较好的结晶化程度。 相似文献
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采用阴极恒电位沉积方法, 在TiO2表面沉积制备出CdS纳米粒子. XRD和SEM测试结果表明, CdS粒子的结构以六方晶相为主, 粒径分布均匀, 表面形貌呈菜花状. 通过调节沉积电位和沉积时间等因素在一定程度上可以控制CdS纳米粒子的生长. 随着沉积电位变负, CdS粒子的粒径逐渐减小. 沉积时间越短, 粒子粒径越小. 紫外-可见吸收光谱测试结果表明, 不同条件下制备出来的CdS粒子表现出一定的量子尺寸效应. 此外, 沉积条件也会影响ITO/TiO2/CdS复合半导体薄膜的光电性能. 相似文献
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采用恒电位方法研究了室温离子液体1-丁基-3-甲基咪唑氟硼酸盐([BMIM]BF4)中氧化铟锡(ITO)电极表面Cu的沉积过程. 结果表明, Cu2+在ITO表面经中间产物Cu+还原为Cu. 采用XRD和SEM对不同电位下沉积层的组成和结构进行了考察. 结果表明, 表面组成和结构与沉积电位有关. 在较正电位下沉积所得为Cu/Cu2O的混合纳米粒子; 在较负电位下为Cu纳米粒子. 随着沉积电位逐渐变负, 其形貌经历了花状、 棒状向球形纳米粒子转变的过程, 且所得沉积膜逐渐变得致密, 其中Cu纳米粒子膜表现出较强的表面增强拉曼散射(SERS)活性, 并且SERS信号均一. 相似文献
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聚酰亚胺(PI)薄膜作为柔性有机发光显示(OLED)基板材料应用时, 需要满足玻璃化转变温度(Tg)大于450 ℃和热膨胀系数(CTE)在0~5×10-6 K-1之间. 为了提高PI薄膜的热性能, 本文合成了2,7-占吨酮二胺 (2,7-DAX), 并将其与均苯四甲酸二酐(PMDA)和2-(4-氨基苯基)-5-氨基苯并噁唑(BOA)共聚制备了一系列新型PI薄膜. 研究了PI薄膜的聚集态结构、 耐热性能、 尺寸稳定性和力学性能. 结果表明, 占吨酮结构和苯并噁唑结构提高了PI分子链的刚性与线性, 使分子链在平面内紧密堆积与取向, 制备的PI薄膜综合性能优异, 玻璃化转变温度高于408 ℃, CTE在-5.0×10-6~8.1×10-6 K-1之间, 拉伸强度大于140 MPa, 拉伸模量大于4.2 GPa, 断裂伸长率为7.1%~20%, 5%热失重分解温度(T5%)在601~624 ℃之间. 其中, PI-50和PI-60薄膜具有超高玻璃化转变温度和超低热膨胀系数, Tg高于450 ℃, CTE分别为2.1×10-6 K-1和1.6×10-6 K-1. 制备的系列PI薄膜作为柔性OLED基板材料有潜在应用前景. 相似文献