铟离子总浓度对铟锡氧化物(ITO)粉末粒径的影响

以纯铟、SnCl4·5H2O为原料,采用络盐法制备了纳米晶的铟锡氧化物(ITO)粉末.通过对铟锡复合络合盐(NH4)1.91(In0.91Sno.09)Cl5·?H20的制备研究,充分证实了反应初始溶液中络离子的存在.研究了铟离子总浓度对ITO粒径的影响,结果表明:由于络离子的存在控制了游离In3+的浓度,从而可以在一...     

连续离子层吸附与反应法(SILAR)生长ZnO多晶薄膜的研究

采用连续离子层吸附与反应法(SILAR),以锌氨络离子([Zn(NH₃)₄]²⁺)为前驱体溶液,在玻璃衬底上沉积了ZnO薄膜,以XRD和SEM等手段分析了薄膜的晶体结构和表面、断面形貌,考察了空气气氛下的退火过程对ZnO薄膜晶体结构与微观形貌的影响,并初步探讨了以SILAR方法沉积ZnO薄膜的机理.结果表明,经200次SILAR沉积循环,所得ZnO薄膜为红锌矿结构的多晶薄膜,沿<002>方向择优生长;薄膜表面致密、光滑均匀,厚度约800nm.退火处理使ZnO薄膜氧缺位减少,晶粒沿c轴取向增强;随退火温度升高,锌间隙原子增加;500℃退火时,ZnO薄膜发生再结晶.减小前驱体溶液的[NH₃·H₂O]/[Zn²⁺]比率可提高ZnO薄膜生长速率.     

Al13低温合成尖晶石和尖晶石氧化锆复合材料

以［AlO₄Al₁₂(OH)₂₄(H₂O) ₁₂］⁷⁺（简写为Al₁₃）溶液为铝源, 采取湿化学的方法合成尖晶石及尖晶石氧化锆复合粉体. 采用²⁷Al NMR、DSC-TG、XRD和FTIR等研究前驱体结构、反应过程及微结构演变. 将氯化镁、氢氧化钠混合研磨后加入Al₁₃溶液中, 得到由Mg₆Al₂CO₃(OH)₁₆·4H₂O 和 β-Al(OH)₃组成的前驱体, 经过600℃煅烧形成尖晶石, 更高温煅烧产物仍为尖晶石单相. 以Al₁₃、MgCl₂·6H₂O和ZrOCl₂·8H₂O为原料制备的前驱体经600℃煅烧, 同样获得尖晶石和四方相氧化锆. Al₁₃粉末和尖晶石氧化锆复合粉体的FTIR谱显示, 归属于［AlO₆］的吸收谱带由608cm^-1移至 601cm^-1, 归属于 ［AlO₄］ 的吸收谱带由761cm^-1 移至 723cm^-1. 前驱体中形成的AlOMg键合是以Al₁₃为铝源合成尖晶石和尖晶石氧化锆复合粉体具有低温合成的主要原因.     

纳米相铁红粒子的液相制备

由０．２ｍｏｌ·Ｌ^－１Ｆｅ^３＋采用微波诱导加热制备了纳米尺寸的准立方形和纺锤形α－Ｆｅ_２Ｏ_３粒子,与常规加热方式比较微波加热制得的α－Ｆｅ_２Ｏ_３粒子粒径小且分布均匀,实验证明无机离子加 Ｈ^＋、ＯＨ^－和 Ｎａ^＋等的加入可明显加速反应速率．     

化学组成对EMD电化学行为的影响

为了了解化学组成对电解二氧化锰(EMD)电化学行为的影响,分析了三种商品 EMD的组成,它们分别为Mn_0.881⁴⁺Mn_0.044³⁺O_1.655^2-(OH)_0.345^-、Mn_0.880⁴⁺Mn_0.048³⁺O_1.666^2-(OH)_0.334^-和 Mn_0.879⁴⁺Mn_0.054³⁺O_1.677^2-(OH)_0.322^-, X射线衍射表明晶型为γ-MnO₂.通过循环伏安、恒流放电、 电位-时间关系等实验研究其电化学行为,结果表明,EMD中结合水含量(即阳离子空位数) 增加时,样品开路电压升高、放电容量增大、第1电子还原的峰电位正移.     

掺铒碲酸盐玻璃的热力学稳定性和光谱性质的研究

分析了掺Er³⁺碲酸盐玻璃的热力学稳定性能,研究了掺Er3+碲酸盐玻璃的吸收和荧光光谱性质;应用Judd-Ofelt理论计算了碲酸盐玻璃中Er3+离子的强度参数Ω(Ω₂=4.79×10^-20cm², Ω₄=1.52×10^-20cm²,Ω₆=0.66×10^-20_cm2),计算了离子的自发跃迁几率,荧光分支比;应用McCumber理论计算了Er3+的受激发射截面(σ_e=10.40×10^-21cm²)、Er³⁺离子⁴I_13/2→⁴I_15/2 发射谱的荧光半高宽(FWHM=65.5nm)及各能级的荧光寿命(⁴I_13/2能级为τ_rad=3.99ms);比较了不同基质玻璃中Er3+离子的光谱特性,结果表明掺铒碲酸盐玻璃更适合于掺Er³⁺光纤放大器实现宽带和高增益放大.     

Li2MnO3的柠檬酸盐溶胶-凝胶法合成及离子导电性

以Ｌｉ_２ＣＯ_３、ＭｎＣＯ_３为原料,用柠檬酸盐溶胶凝胶法合成了Ｌｉ_２ＭｎＯ_３超微粉．对合成的材料进行了ＤＴＡ、ＴＧ、ＸＲＤ和ＴＥＭ等表征,并应用交流阻抗谱技术测定了样品的电导率．结果表明,６５０。Ｃ以上生成Ｌｉ_２ＭｎＯ_３纯相超微粉,粒径在５０nｍ以下．在１８～４００℃温度范围内,产物烧结体的离子导电率为１０^－６～１０^－３Ｓ·ｃｍ^－１,其电导活化能为４４．８７ｋＪ·ｍｏｌ^－１．     

共沉淀法制备掺杂氧化锌压敏陶瓷粉料热力学分析

本文通过对Ｍｅ^ｎ＋（Ｚｎ^２＋;Ｃｒ_３^＋,Ｍｎ^２＋;Ｓｂ^３＋,Ｂｉ^３＋,Ｃｏ^２＋）－ＮＨ_３－ＣＯ_３^２－－Ｈ_２Ｏ体系进行热力学分析的基础上,获得了Ｍｅ－ＮＨ_３－ＣＯ_３^２－Ｈ_２Ｏ体系中的ｌｇ［Ｍ］_T－ｐＨ关系图,得到了用ＮＨ_４ＨＣＯ_３和ＮＨ_３·Ｈ_２Ｏ作沉淀剂,用共沉淀法制备掺杂氧化锌压敏陶瓷粉料时,最佳共沉淀ｐＨ为７．０左右．     

LiNiO2热分解反应动力学研究

用ＤＴＡ和ＸＲＤ研究了ＬｉＮｉＯ_２在空气中的热分解过程为：ＬｉＮｉＯ_２（ｓ）→(６５０～７２０℃)Ｌｉ_２Ｎｉ_８Ｏ_{１０（ｓ）}＋４Ｌｉ_２Ｏ_（ｓ）＋Ｏ_２（ｇ）→(８５０～９５０℃)Ｌｉ_２Ｏ_（ｓ）＋８ＮｉＯ_（ｓ）＋１／２Ｏ_２（ｇ） →(１０００～１１５０℃)ＮｉＯ（ｓ）＋Ｌｉ_２Ｏ_（ｇ）用 Ｄｏｙｌｅ－Ｏｚａｗａ法和 Ｋｉｓｓｉｎｇｅｒ法计算了各反应阶段的表观活化能分别为 ７４７．１８±１．０ ｋＪ·ｍｏｌ^－１、９３２．４６±１．０ ｋＪ·ｍｏｌ^－１和 １１２６．９７±１．０ ｋＪ·ｍｏｌ^－１．用 Ｋｉｓｓｉｎｇｅｒ法确定了反应级数和频率因子,确定了三个阶段的动力学方程分别为 ｄα／ｄt＝１．７３６ｘ１０３９ｅ^{－９００００／Ｔ}（１－α）^{１．０５７}; ｄα／ｄｔ＝１８０６×１０^３９ｅ^{－１１１５００／Ｔ}（１－α）^{０．８４４};ｄα／ｄｔ＝４．２６２×１０４２ｅ^{－１３５０００／Ｔ}（１－α）^{１．２７５}     

单分散纳米氧化铟锡粉末的水热合成

以金属铟和锡为原料,于碱性环境240℃水热合成12h并经500℃煅烧2h得到了 粒径为70±10nm,比表面积为11 m²／g的高纯氧化铟锡(ITO)粉末.由SEM、激光粒度测试 仪和BET三种方法分析得到的粉末平均粒径相吻合,证明制备的粉末是单分散状态的.研究 还发现,提高铟锡初始浓度和氢氧化钠过量浓度均有利于小粒径单分散ITO粉末的制备,但 过高的氢氧化钠过量浓度会使粉末出现团聚.     

高阻In掺杂CdZnTe晶体缺陷能级的研究

利用低压垂直布里奇曼法制备了不同In掺杂量的CdZnTe晶体样品, 采用低温光致发光谱(PL)、深能级瞬态谱(DLTS)以及霍尔测试等手段研究了In掺杂CdZnTe晶体中的主要缺陷能级及其可能存在的补偿机制. PL测试结果表明, 在In掺杂样品中, In原子占据了晶体中原有的Cd空位, 形成了能级位于E_c-18meV的替代浅施主缺陷[In_Cd^+], 同时 [In_Cd⁺]还与[V_Cd^2-]形成了能级位于E_v+163meV的复合缺陷[(In_Cd⁺-V_Cd^2-)^-]. DLTS分析表明, 掺In样品中存在导带以下约0.74eV的深能级电子陷阱能级, 这个能级很可能是Te反位[Te_Cd]施主缺陷造成的. 由此, In掺杂CdZnTe晶体的电学性质是In掺杂施主缺陷、Te反位深能级施主缺陷与本征受主缺陷Cd空位和残余受主杂质缺陷补偿的综合结果.     

电沉积NiHCF薄膜在碱土金属溶液中的电控离子分离性能

采用电沉积方法在铂基体上制备出电活性NiHCF(Nickel Hexacyanoferrate)薄膜,在碱土金属溶液中考察了薄膜电极对碱土金属离子的电控离子分离性能.通过循环伏安法在0.1mol·L-1Mg(NO3)2、Ca(NO3)2、Sr(NO3)2和Ba(NO3)2溶液中可逆置入和释放碱土金属离子,比较了不同溶液中NiHCF膜电极的电活性、电化学行为和离子的置入机制;在0.1mol·L-1[Mg(NO3)z Ba(NO3)2]混合溶液中结合电化学石英晶体微天平(EQCM)原位检测了不同浓度下膜电极氧化还原过程中的伏安特性曲线和频率响应,分析了薄膜对Mg/Ba离子的选择性;并通过XPS测定了氧化还原状态下NiHCF膜的化学组成及元素价态.结果表明,NiHCF膜在二价碱土金属溶液中具有可逆的离子交换行为,对Ba2 离子的选择性大于Mg2 离子,通过电控离子分离方法可以实现碱土金属离子的有效分离.     

Optimum preparation of low-resistivity indium tin oxide nanopowders via polyacrylamide gel route using orthogonal experiment

Indium tin oxide (ITO) is a promising transparent conducting oxide material for photoelectric devices. In this work, the low-resistivity cubic ITO (c-ITO) nanopowders were synthesized via polyacrylamide gel route. The orthogonal experiment design was applied to optimize preparation process that was as follows: n(AM)/n(MBAM)?=?25:6, c(In³⁺)?=?0.3 mol/L, calcination temperature (T)?=?700 °C, holding time (t)?=?9 h. Subsequently, the thermal decomposition process of ITO xerogel, crystal structure, morphology, and electrical conductivity of the optimum sample were characterized systematically. The results indicated that the thermal decomposition of ITO xerogel was a multi-step kinetic reaction process, and the activation energy of reaction depended on the conversion of ITO xerogel. The powders were well indexed to cubic ITO crystal phase, and presented a concentrated particle size distribution of 34–54 nm and nearly spherical-like morphology. The low-resistivity value of 0.161 Ω·cm was obtained under the optimum preparation process. Moreover, the formation mechanism of ITO nanopowders prepared via polyacrylamide gel route was also investigated. The synthesized ITO nanopowders with low resistivity present wide application prospects of next-generation ITO functional materials.

     

Modeling the structural properties and energies of transparent conducting oxides

In the current study we evaluate the use of a dumped shifted force electrostatic interaction model for the study of the structural properties of indium oxide and tin-doped indium oxide (ITO). This model is found to be computationally efficient and accurate in the calculations. More specifically, the ion positions of In₂O₃, the preference of b-sites In substitution with Sn and the lattice constant of ITO anomalous dependency on Sn content varying from 3% to 6% calculated with this model agree with the experimental data and other theoretical first principle studies. For Sn content higher than 6% the calculated data deviate from the experimentally observed as the existence of the In₄Sn₃O₁₂ phase was not taken into account. Also, we found an agreement to the Vegard's law of the lattice constant with simple In substitution with Sn ions. Finally the bulk modulus calculated for the ITO (92-97 GPa) is in good agreement with experimental data for ITO films.     

Nd:GdxY1-xCa4O(BO3)3晶体的生长及其光谱性能研究

利用熔体提拉法生长了大尺寸,高质量的新型激光自倍频晶体Nd:GdxY1-x(Ca4O(BO3)3(简称Nd:GdYCOB),对Nd:GdYCOB晶体的XRD衍射图进行指标化,得到它的晶胞参数为a=8.080A;b=16.016A;c=3.538A,β＝101．18,μ＝491．1A3,对取自不同部位的晶体粉末进行ICP原子发射光 分析表明晶体整体组份均匀一致,根据熔体和晶体粉末的ICP数据计算,Nd:GdYCOB晶体中Nd3 的分凝系数为0．63,首次报道了Nd:GdYCOB晶体200－3000nm室温透过光谱和室温荧光光谱及荧光寿命,室温透过光谱表明Nd:GdYCOB晶体的紫外吸收边在－220nm,具有很宽的透光波段（－220－2700nm);Nd:GdYCOB晶体在800nm附近存在很强的吸收,适合于LD泵汪,为光光谱表明Nd:GdYCOB晶体是一种很有潜力的RGB（red,green,blue)激光自倍频晶体,掺杂4％,5％ Nd:GdYCOB晶体的荧光寿命分别为105us和100us。     

膨胀石墨CuCl2-EGICs的微观结构TEM研究

采用透射电镜研究了以膨胀石墨为主体材料合成的ＣｕＣｌ２－ＥＧＩＣｓ微观结构,包括垂直和平行石墨碳原子层的层间结构,层面结构,根据Ｘ射线衍射参数计算获得２、３、４阶ＣｕＣｌ２－ＥＧＩＣｓ的层间距Ｉｃ值,与理论计算值近拟。     

Effects of (NH4)2Sx treatment on the electrical and optical properties of indium tin oxide/conducting polymer electrodes

In this study, the effects of (NH₄)₂S_x treatment on the electrical and optical properties of the indium tin oxide (ITO)/poly(3,4-ethylenedioxythiophene) doped with poly(4-styrenesulfonate) (PEDOT:PSS) electrodes were researched. The authors found that (NH₄)₂S_x treatment could result in suppressing the hysteresis-type current-voltage characteristics related to the interfacial capacitance variation and a reduction in the equivalent refractive index of the ITO/PEDOT:PSS electrodes, owing to the improvement in the interfacial stability of the ITO/PEDOT:PSS electrodes and a reduction in the interface trap-states related charge store at the ITO/PEDOT:PSS interface. This implies that the ITO/PEDOT:PSS electrodes fabricated using the (NH₄)₂S_x-treated ITO may produce a higher extraction efficiency for ITO/PEDOT:PSS-based optoelectronic devices.     

Lu2O3:Yb3+, Ho3+纳米粉体的发光性能研究

采用共沉淀工艺合成了Yb3 离子和Ho3 离子共掺杂的Lu2O3纳米粉体,研究了粉体的斯托克斯(Stokes)和反斯托克斯(Anti-Stokes)发光特性以及煅烧温度对粉体发光性能的影响.在氙灯447.5nm和半导体激光器980nm激发下样品均发射出明亮的绿光,观察到了不同Ho3 离子浓度掺杂的纳米粉体的浓度淬灭现象.发射强度与激发功率的关系表明Anti-Stokes发光是双光子过程,能量转移是主要的上转换机制.Ho3 离子的5F4,5S2能级在不同波长激发下的衰减时间也证实了浓度淬灭及能量转移现象.     

微波场下纳米Mg-Al-LDHs及PO43-,P2O74-柱撑Mg-Al层状双氢氧化物的合成

用微波加热反应-变速滴加共沉淀法合成了[Mg-Al-CO3]纳米层状双氢氧化物，并以[Mg-Al-CO3]纳米层状双氢氧化物为前体，用微波加热反应一离子交换法制备了PO4^3-，P2O7^4-柱撑Mg-Al层状双氢氧化物．该法合成的[Mg-Al-CO3]纳米层状双氢氧化物的粒径约为10～40nm．讨论了微波和变速滴加碱液的速度对纳米层状双氢氧化物的合成的影响．用FT-IR、TEM与XRD对产物进行了表征，结果表明在微波加热反应的条件下可在短时间内用PO4^3-,P2O7^4-彻底交换CO3^2-。     

Indium tin oxide films made from nanoparticles: models for the optical and electrical properties

Porous thin films comprising nanoparticles of In₂O₃:Sn (known as indium tin oxide, ITO) were made by spin coating followed by annealing. The nanoparticles were prepared by a wet chemical technique. The films had a luminous transmittance of ∼90% and an electrical resistivity of ∼10⁻² Ω cm. Spectral transmittance and reflectance were analyzed by first representing the ITO nanoparticles within the Drude theory, with a frequency-dependent scattering time characteristic for ionized impurity scattering, and then applying effective medium theory to account for the porosity. It was found that the individual nanoparticles had a resistivity of ∼2×10⁻⁴ Ω cm, i.e. their electrical properties were comparable to those in the best films made by physical or chemical vapour deposition. Temperature-dependent electrical resistivity data for the films could be reconciled with a model for fluctuation induced tunneling between micrometer-size clusters of internally connected ITO nanoparticles.