Structural design and characterization of a new chalcone molecular derivative crystal DMNC with high second-order nonlinear coefficient

1.Text In recent years,new organic second-order nonlinear optical materials have been widely used in optical imaging,data storage,information processing and communication,etc.[1].Therefore,designing and growing crystalline materials with strong second-order nonlinear effects is one of the current research hotspots[2].

双功能NiCo2S4多面体的构建及其超级电容器和锂离子电池性能

双功能NiCo2S4多面体结构具有优异的电化学性能,适用于超级电容器和锂离子电池.本文采用水热方法合理设计并成功合成了具有高表面积、稳定结构、良好结晶性的NiCo2S4多面体结构.其特定的多面体结构具有离子反应的活性位点和足够的离子传输空间,因此可实现包括高比电容、良好的速率能力和循环稳定性在内的优异电化学性能.作为超级电容器的NiCo2S4电极在1 A/g时具有1298 F/g的比电容,在20 A/g时具有80.4%电容保持率. 8000次循环后电容仍保持90.44%.此外,NiCo2S4作为锂离子电池的阳极,在0.5 C时具有807.6和972.8 m Ah/g的初始充电/放电能力.该工作为下一代储能应用中组装具有出色电化学性能的电极和器件提供了一条可行的途径.

Realization of warm white light emitting in single phase Gd(P_(x)V_(1−x))O_(4):y at% Sm^(3+),1 at% Bi^(3+) phosphor

A series of single phase,warm white light emitting phosphors,Gd(P_(x)V_(1−x))O_(4):y at%Sm^(3+),with 1 at%Bi^(3+) doping concentration were synthesized by high temperature solid state method in this work.The experimental results indicate broadband cyan emission of Bi^(3+)and characteristic orange-red emission of Sm^(3+)can be effectively tuned by changing the ratios of PO^(3−)_(4)/VO^(3−)_(4) in Gd(P_(x)V_(1−x))O_(4):1 at%Sm^(3+),1 at%Bi^(3+),and the energy transfer process among VO^(3−)_(4),Sm^(3+),Bi^(3+) also can be adjusted.Based on this,warm white light emitting can be realized by further optimizing the doping concentration of Sm^(3+) in the phosphors.At 423 K,the PL intensity of Gd(P_(0.7)V_(0.3))O_(4):2 at%Sm^(3+),1 at%Bi^(3+) remains~84.3%of the initial value at 293 K,while the measured quantum efficiency is 67.8%.EL spectrum analysis results of the fabricated white light emitting diode(wLED)based on a 310 nm UV-chip and Gd(P_(0.7)V_(0.3))O4:2 at%Sm^(3+),1 at%Bi^(3+)phosphors imply low correlated color temperature(3132 K)and appropriate color-rending index(R_(a)=82.7).These results demonstrate that Gd(P_(0.7)V_(0.3))O4:2 at%Sm^(3+),1 at%Bi^(3+)is a good candidate for manufacturing UV-activated warm white light emitting diodes.

Effect of OH^- on fluorescence properties in 1.5-1.6 μm for Er:Yb:YCOB crystal

FTIR absorption spectra indicate that H^+can easily enter the crystal structure and form OH^-centers in Er:Yb:YCOB and O-H bonds prefer to lie in the a-c plane.Within our current studied concentration level,crystal samples with higher OH-abso rption coefficie nts demonstrate stro nger fluo rescence intensity and longer fluorescence lifetime at 1535 nm.As the stretching vibration energy of OH-group approximately corresponds to the energy gap between the 4 I11/2 and 4 I13/2 levels of Er^3+,and thus,OH^-ions can shorten the fluorescence lifetime of Er^3+-4I11/2 level by the phonon-assisted cross-relaxation process between the Er^3+and OH-ions.Our curre nt results confirm that a certain conte nt of OH ions can enhance the ene rgy transfer process from Yb^3+to Er^3+and subsequently promote fluorescence output in 1.5-1.6μm.

Synthesis, crystal structure and thermal analysis of a new stilbazolium salt crystal

A new organic crystal of 4-N, N-dimethylamino-4＇-N＇-methyl-stilbazolium benzene sulfonate （DASBS） was synthesized and characterized for the first time. It is a derivative of 4-N, N-dimethylamino-4＇-N＇-methyl-stilbazolium tosylate （DAST） with the benzene sulfonate replacing p-toluenesulfonate. Single crystal XRD demonstrated that the crystal structure of DASBS. H20 was triclinic. The thermal analysis of this new crystal was also conducted, and the melting point was obtained to be 232℃.