退火对Tb掺杂ZnAl层状双金属氢氧化物的结构和荧光特性的影响

采用共沉淀法制备Tb^(3+)掺杂的锌铝水滑石(Tb-ZnAl-LDH),然后将Tb-ZnAl-LDH分别在200、400、600、800、1 000℃进行退火处理。X射线衍射(XRD)测试结果发现:200℃时Tb-ZnAl-LDH的层状结构发生坍塌,400℃时层板断裂,并出现ZnO相。随着退火温度的升高,ZnO相的衍射峰增强,到1 000℃时出现尖晶石(ZnAl_2O_4)结构。荧光光谱(FL)结果表明:原生Tb-ZnAl-LDH呈现很强的绿光,该绿光源于Tb^(3+)离子的5D4-7FJ(J=3,4,5,6)跃迁。经200℃退火后,源于Tb^(3+)的绿光峰大大减弱;当退火温度增加至400℃时,这些分立的绿光峰消失,出现很宽的峰(450~650 nm)。这些研究结果表明,层状ZnAl LDH主体材料更有利于Tb^(3+)离子的发光。此外,扫描电镜(SEM)观察发现,当Tb-ZnAl-LDH的退火温度达到400℃时,其形貌开始出现明显的改变。

CdS纳米粒子/层状硅酸盐复合物的合成及光学性质的研究

通过离子交换和后续S2-的引入将CdS纳米粒子引入到层状硅酸盐（Na-Octosilicate）中以形成CdS/Octosilicate复合物。粉末X射线衍射表明,CdS/Octosilicate复合物保持主体层状硅酸盐的结构。CdS/Octosilicate复合物的组分分析基于ICP-AES、SEM-EDX、CHN元素以及热重TG结果。光致发光光谱（PL）表明：当CdS纳米粒子引入到主体层状硅酸盐中后,CdS中的550 nm峰位明显向高能方向移动（移至528 nm）;紫外-可见散射谱（UV-vis）表明,随着层状硅酸盐中CdS含量的增加,复合物的能带边从高能移向低能;透射电子显微镜（TEM）观测证实,硅酸盐主体层中CdS纳米粒子的尺寸为3-5 nm,而且随着主体硅酸盐中CdS纳米粒子数量的增加,CdS纳米粒子趋于团聚。这些结果表明,CdS的光学性能能够被层状硅酸盐Octosilicate修饰。

Tb掺杂MgAl-LDH绿光对苯丙氨酸响应性

探讨了Tb^(3+)掺杂Mg/Al双金属氢氧化物(Tb-LDH)的绿光对苯丙氨酸(Phen)的响应特性。结果发现:源于Tb^(3+)离子的~5D_4-~7F_J(J=5,6)跃迁所致的强绿光出现在Tb-LDH。当Tb-LDH分别暴露于0.01、0.05、0.10、0.25和0.50 mol·L^(-1)的苯丙氨酸溶液时,Tb^(3+)的绿光显著减弱甚至猝灭;而源于苯丙氨酸的蓝光则呈现不同的变化。Tb-LDH的绿光对苯丙氨酸的最佳响应浓度为0.05 mol·L^(-1),这种荧光响应性可能是由于Tb-LDH与苯丙氨酸之间的相互作用所致,且被X-粉末衍射(XRD)和傅里叶红外光谱仪(FTIR)进一步证实。

浅析在线水洗水质对化学镍金工艺品质的影响

文章结合生产实例,对印制电路板化学镍金工艺几类常见品质问题的产生原因及解决办法进行了研究,阐释了在线水洗水质对化学镍金工艺品质影响的重要性。

Synthesis of new Tb-doped Zn-Al LDH/tryptophan hybrids and their fluorescent property

A series of hybrids based on Tb-doped Zn-Al layered double hydroxides （Tb-LDHs） combined with tryptophan （hereafter shortened as Try） were synthesized by soft-chemical method. The composition, structure, and fluorescence of the Tb-LDH/Try hy-brids were analyzed by various characterizations. Compositional analysis indicated that the content of tryptophan present in the hybrids gradually increased while the Tb-LDH reacted with 0.05, 0.1, and 0.25 mol/L Try solution, respectively. XRD results revealed that new reflections appeared in the Tb-LDH/Try hybrids. TGA curves of the Tb-LDH/Try hybrids were different from that of Tb-LDH and Try. IR spectra manifested that the IR spectra of the hybrids were characteristic of the Try and Tb-LDH. Fluorescent spectra sug-gested that the green emission due to5D4→7F5 transition of Tb3＋ greatly decreased but not quenched, and the emission attributed to Try obviously increased. Meanwhile the fluorescent spectra of Tb-LDH/Try hybrids presented broad continuous bands in visible region.

Photoluminescence of Tb-doped MgAl-LDHs depending on phase transition caused by annealing

This paper presented the photoluminescence of Tb-doped Mg-A1 layered double hydroxides （Tb-doped MgAI-LDHs） depending on phase transition caused by annealing. Tb-doped MgA1-LDHs structure transformed from hexagonal LDHs, cubic MgO to spinel MgA1204 phase as temperature varied from 200 to 1000 ℃. Emission and excitation spectra of Tb-doped MgAI-LDHs obviously changed with phase transformation. The emissions of Tb3＋ ions attributed to 5D4→TFJ transitions （J=3, 4, 5, 6） were observed in the emission spectra of all the Tb-doped samples. The ratio of （SD4→7F5）/（SD4→7F6） emission intensity, which was sensitive to surroundings of Tb3＋ ion, markedly enhanced with temperature rising to 600 from 400 ℃. Over 600 ℃, the ratio of （SD4→TF5）/ （SD4→TF6） intensity tended to decreasing up to 1000 ℃. The change concerning the ratio of the （SD4→7F5）/（SD4→TF6） emission intensity might be due to various surroundings of Tb3＋ induced by phase transformation.