纳米ZnO基掺杂气敏元件阵列的制备与特性

以金属蒸气氧化法制备的纯纳米ZnO为气敏原料,通过丝网印刷技术在Al2O3基片上制得纯ZnO和掺杂ZnO的气敏元件阵列。结果表明,元件阵列具有低的功耗,纯ZnO气敏元件阵列在350~400℃对橙汁、可乐、酒精和汽油有较高的敏感性,灵敏度分别为2.9,2.9,53.5和43.4。通过Bi2O3+Cu2O的掺杂,可以降低纯ZnO的电导,并进一步提高气敏元件在250~350℃温度区间对汽油的敏感性。并对其气敏机理进行了探讨。     

聚噻吩/WO_3复合纳米材料的制备及气敏性能

采用水合肼法制备WO3粉体,再以无水FeCl3作氧化剂,通过原位化学氧化聚合制备了不同聚噻吩(PTh)掺杂量的PTh/WO3复合纳米材料。并研究了用其制备的气敏元件的气敏性能。结果表明:气敏元件对H2S和NOx有较高的灵敏度和较好的选择性。用质量分数w(PTh)为5%的PTh/WO3复合纳米材料制备的气敏元件,在加热电压为2.25V时,对体积分数φ(NOx)为5×10–6的灵敏度可达77.14;用w(PTh)为20%的PTh/WO3复合纳米材料所制之气敏元件,在加热电压为2.43V时,对φ(H2S)为20×10–6的灵敏度达63.27。     

钇掺杂纳米α-Fe2O3的合成及气敏性能研究

采用柠檬酸sol-gel法制备了不同掺杂量的Y2O3-Fe2O3(w(Y2O3)=0~7%)纳米粉体材料,并用X射线衍射仪、透射电镜等测试手段分析了材料的微观结构,并进行了气敏性能测试。研究发现:掺杂适量Y2O3可抑制α-Fe2O3晶粒的生长,提高粉体材料的气敏性能,其中掺杂量为5%的烧结型气敏元件在160℃的较低温度条件下,对汽油有较高的灵敏度,较好的选择性及响应–恢复特性,且线性检测范围较宽。     

溶胶–凝胶法WO_3纳米粉体的气敏性能研究

采用溶胶–凝胶法制得了不同掺杂量的TiO2-WO3(TiO2质量分数为0~5%)纳米粉体材料,利用X射线衍射仪、透射电镜等测试手段分析了材料的微观结构,并进行了气敏性能测试。研究发现:适量TiO2的掺杂可改变WO3的晶型,抑制晶粒的生长,提高粉体材料的气敏性能,其中掺杂量为3%的烧结型气敏元件在220℃时对汽油有较高的灵敏度,线性检测范围较宽,且抗干扰能力强。     

微波辅助合成纳米WO_3/TiO_2复合材料及其气敏性能

为改善WO3基敏感材料的气敏性能,采用微波回流法一次性合成了纳米WO3/TiO2复合材料,并研究TiO2掺杂量对用其制备的气敏元件气敏性能的影响。结果表明:此气敏元件对体积分数为100×10-6的NOx、二甲苯、H2S和丙酮气体具有较强的敏感性,掺杂w(TiO2)为20%的元件,对H2S和NOx的灵敏度分别为31.18和695.84;掺杂w(TiO2)为30%的元件,对二甲苯和丙酮的灵敏度分别为39.19和35.69。     

锌掺杂量对In_2O_3电导和气敏性能的影响

用化学共沉淀和热处理法于pH11.5～12.5时,用(NH4)2CO3作沉淀剂,制备了Zn2+掺杂的In2O3微粉。研究了Zn2+掺杂量对In2O3气敏元件电导和气敏性能的影响。结果发现,ZnO与In2O3可形成有限固溶体In2-xZnxO3(0≤x≤0.10);In1.95Zn0.05O3气敏元件在223℃工作温度下,对浓度为4.5×10–7mol/L的C2H5OH的灵敏度高达174.4,且选择性也好。     

掺Sm~(3+)的WO_3纳米粉体的制备及其NO_2气敏性能

通过固相研磨法制得了一系列掺有Sm3+的WO3纳米粉体,利用XRD、TEM等测试手段,对其物相﹑结构进行了表征。结果表明:掺Sm3+的WO3纳米粉体结晶良好,平均粒径为50nm。利用该纳米粉体制成气敏元件,并采用静态配气法测试了元件的气敏性能。研究发现:当掺杂x(Sm3+)=0.5%时,元件在160℃下对体积分数为30×10-6的NO2气体的灵敏度高达169,响应时间为8s,是一种较为理想的低温NO2气敏元件。     

掺Sm2O3的SnO2纳米粉体对C2H2气敏特性的研究

用化学沉淀法制备了SnO2纳米材料,利用XRD和SEM对合成产物进行了表征.采用旁热式结构制成了以SnO2为基体材料,掺杂Sm2O3的气体传感器.通过元件对C2H2气敏特性的测试表明:Sm2O3的掺杂可以明显地提高SnO2气敏材料对C2H2气体的灵敏度,当工作温度为180℃,C2H2浓度为1000ppm时,元件的灵敏度为64,响应恢复时间分别为3和20s.讨论了不同相对湿度对元件气敏特性的影响.     

掺Sm2O3的SnO2纳米粉体对C2H2气敏特性的研究

用化学沉淀法制备了SnO2纳米材料,利用XRD和SEM对合成产物进行了表征.采用旁热式结构制成了以SnO2为基体材料,掺杂Sm2O3的气体传感器.通过元件对C2H2气敏特性的测试表明:Sm2O3的掺杂可以明显地提高SnO2气敏材料对C2H2气体的灵敏度,当工作温度为180℃,C2H2浓度为1000ppm时,元件的灵敏度为64,响应恢复时间分别为3和20s.讨论了不同相对湿度对元件气敏特性的影响.     

掺杂改善SnO_2甲醛气敏元件灵敏度特性的研究

用纳米SnO2制作了旁热式气敏元件。用掺杂方法提高SnO2甲醛气敏元件的灵敏度,掺杂剂包括Pd,Sb,Ti,Zr,Cu,Ag,Mn等。在SnO2气敏元件中分别掺杂质量分数2%Pd和2%Zr对提高元件灵敏度有显著效果。未掺杂SnO2、掺杂质量分数2%Pd和2%Zr的气敏元件对体积分数为5×10-5甲醛的灵敏度分别为1.33,2.38,2.08,但是掺杂在改善元件对乙醇的选择性方面作用不大。分析了掺杂改善SnO2气敏元件灵敏度的原理,当SnO2表面吸附还原性气体时,吸附气体提供电子,使半导体表层的导电电子数增加,引起电导率增加、电阻下降。吸附气体浓度越高,电阻率变化越大,元件灵敏度越大。     

SrTiO3压敏电阻耐浪涌电流特性的研究

本文研究了用一次烧成法制备的Ｍｎ＾２＋和Ｃｕ＾＋为受主掺杂的ＳｒＴｉＯ３低压压敏电阻，在浪涌电流冲击后，其压敏和介电特性的变化规律及影响因此。证Ｃｕ＾＋掺杂的试样具有较高的耐浪涌电流能力。     

Effect of terbium doping on structural,optical and gas sensing properties of In2O3 nanoparticles

In this work, the effect of terbium (Tb³⁺) as dopant on the structural, optical, electrical and gas sensing properties of In₂O₃ (indium oxide) nanoparticles has been discussed. In₂O₃ and Tb³⁺-doped In₂O₃ nanoparticles were synthesized by a facile and cost effective co-precipitation method. XRD analysis revealed the formation of bixbyite-type cubic phase for In₂O₃ and Tb³⁺-doped In₂O₃ nanoparticles which was further supported by Raman studies. It was observed that the crystallite size of In₂O₃ nanoparticles decreased, while structural disorder increased with increase in Tb³⁺ concentration. SEM micrographs showed that particles were spherical in shape and EDS corroborated the presence of Tb³⁺ in doped In₂O₃ nanoparticles. A broadening and shifting of Raman peaks with increase in Tb³⁺ content was also observed. For gas sensing characteristics, the nanoparticles were applied as thick film onto the alumina substrate and tested at different operating temperatures for various volatile organic compounds (such as methanol, ethanol, acetone) and ammonia. The results indicated that the sensor based on 5%Tb³⁺-doped In₂O₃ nanoparticles presented much higher sensor response to 50ppm ethanol at 300 °C temperature than the pure In₂O₃ sensor. The enhancement of the response may be attributed to high surface basicity, small size and large lattice distortion of doped In₂O₃ sensor.     

Cu掺杂TiO2纳米晶粉体的形态及光电性能研究

TiO2纳米材料良好的光电性能,为其作为制备染料敏化太阳电池等新型太阳电池的光阳极材料提供了很好的应用基础。采用溶胶-凝胶法成功制备了Cu掺杂的TiO2纳米晶粉体,并利用XRD、EDS、TEM以及荧光分光光度计对样品进行了表征,研究了Cu掺杂对TiO2的物相类型、微观结构、晶粒尺寸以及光致发光性能的影响。结果表明,Cu掺杂使Cu2+取代Ti 4+进入TiO2的晶格中,在抑制TiO2晶粒生长的同时促进了TiO2的晶型转变,但这种抑制和促进作用会随着Cu掺杂量的增加而减弱。3%（原子分数）的Cu掺杂能够有效增强TiO2对光生电子的捕获能力,降低光生电子的复合速率,优化其光电性能。     

Na~+掺杂量对BaBiO_3基陶瓷NTC特性的影响

以BaCO3、Bi2O3为原料,Na2C2O4为掺杂剂,用传统固相法制备了具有NTC特性的BaBi1–xNaxO3陶瓷。用XRD,SEM和ρ-t特性测量仪,研究了Na+掺杂量对该陶瓷的物相、显微结构及电性能的影响。结果表明:BaBi1–xNaxO3陶瓷的B25/85值和室温电阻率ρ25均随着x(Na2C2O4)的增加呈现先减小后变大的趋势;当x(Na2C2O4)为0.050时,获得了具有较好NTC特性的试样,其ρ25为2200?·cm,B25/85值为3365K。     

新型掺铒离子氧氟碲酸盐玻璃的光谱性质

探求新的具有优良的热学和光学性能的基质玻璃系统，是获得具有宽带宽和增益平坦的掺Er^3＋光纤放大器（EDFA）的一种有效途径。制备了一种新型氧氟碲酸盐玻璃TeO2-BaF2-LaF3，并对其热学性能和光学性质进行了测试。应用乍得-奥菲尔特（Judd-Ofelt）理论计算了Er^3＋离子的J-O理论参量和荧光寿命r。探讨了氟化物的引入对碲酸盐玻璃结构的改变的影响，并分析了其对玻璃的热学性质和光学性质的影响。实验发现，获得的氧氟碲酸盐玻璃具有优良的热学稳定性（△T=156.6C），宽的荧光半峰全宽（72nm），长的荧光寿命（r=4．9ms）以及良好的平坦增益特性。该玻璃系统有望成为新的宽带光纤放大器用基质玻璃材料。     

Influence of Ni concentration and Ni3Sn4 nanoparticles on morphology of Sn-Ag-Ni solders by mechanical alloying

The mechanical alloying (MA) process was employed as an alternative method to produce the lead-free solder pastes of Sn-3.5Ag-xNi (x=0.1, 0.5, 1.0, 1.5, and 2.0) in this study. When the Ni concentration was low (x=0.1, 0.5), MA particles agglomerated to a flat ingot with particle sizes >100 μm. For higher Ni concentration (x=1.0, 1.5, and 2.0), MA particles turned into fragments with particle sizes <100 μm. The particle size of the solders appeared to be dependent on the Ni concentration. To reduce the particle size of SnAgNi alloys with low Ni concentration, Ni₃Sn₄ nanoparticles were doped into Sn and Ag powders to derive a Ni₃Sn₄-doped solder. For the Ni₃Sn₄-doped solder, the particle size was smaller than that doped by the pure Ni. The distinction of milling mechanism between Ni₃Sn₄-doped solder and the pure Ni-doped solder by MA process was probed and discussed. In addition, differential scanning calorimetry (DSC) results ensured its feasibility in applying the solder material in the reflow process. Wettability tests between solders and Cu substrate also revealed that the wetting angles for Ni₃Sn₄-doped solder with low Ni concentration (0.1 and 0.5 wt.%) were smaller than those for pure Ni-doped solder. The wetting angles on both Cu substrate and electroplated Ni metallization for SnAgNi solders were also comparable with commercial Sn-3.5Ag and Sn-3.0Ag-0.5Cu solders. Favorable wettability of the as-derived solder in this study was clearly demonstrated.     

掺Fe~(3+)的A-TiO_2的水热法制备及其可见光光催化性能

以硫酸钛为原料,用水热法制备了掺Fe3+的TiO2粉末,并对其晶相结构进行了分析,考察了自制掺Fe3+的TiO2对甲基蓝溶液的光催化性能。结果表明:所制备的TiO2为锐钛矿型TiO2(A-TiO2)。可见光照下,用自制掺Fe3+的A-TiO2降解甲基蓝溶液的最佳条件是:于ρ(甲基蓝)为8mg/L的溶液中加入0.0203g掺Fe3+为5%(摩尔分数)的A-TiO2粉末,并加入φ(H2O2)为4%,室温反应4h,最高降解率达到约88%。