Development of red phosphor Li_(8)CaLa_(2)Ta_(2)O_(13):Eu^(3+)for WLEDs and anti-counterfeiting applications

A set of novel red phosphors Li_(8)CaLa_(2)Ta_(2)O_(13):Eu^(3+)(LCLTO:xEu^(3+))were successfully prepared using a solid-state reaction method.The properties of the prepared samples,including phase purity,elemental composition,and morphology,were systematically investigated using X-ray diffraction,scanning electron microscopy,and diffuse reflectance spectroscopy analyses.The 610 nm maximum emission peak is attributed to the^(5)D_(0)→^(7)F_(2)transition of Eu^(3+)ion under 394 nm irradiation.Among all the LCLTO:xEu^(3+)phosphors,LCLTO:0.6Eu^(3+)showed the strongest emission intensity because of the concentration quenching effect of the electric dipole-dipole in-teraction among the Eu^(3+)ions,which was also demonstrated by the decay curves.Remarkably,the emission intensity of the optimal LCLTO:0.6Eu^(3+)phosphor,which exhibited a high internal quantum efficiency of 49.30%and excellent color purity of 96.79%,was approximately 2.29 times higher than that of commercial Y203:Eu^(3+)red phosphors.The thermal stability of the LCLTO:0.6Eu^(3+)sample with good color stability was meticulously inves-tigated.The fabricated white-light-emitting diode(WLED)exhibited a superior color-rendering index of Ra=82 and chromaticity coordinates of(0.3260,0.3639),suggesting that LCLTO:0.6Eu^(3+)has potential applicability in developing efficient and high-quality WLEDs.Moreover,the prepared LCLTO:0.6Eu^(3+)/PDMS composite film demonstrated exceptional flexural resistance and chemical stability,indicating considerable promise for practical anti-counterfeitingapplications.

Annealing Temperature Effects of TiO2 Nanofiber Anodes for the Rechargeable Lithium Ion Batteries

TiO2 nanofibers（TiO2/NFs） have been synthesized through an electrospinning method and annealed at 400, 500 and 600 ℃ to optimize their systems. The effects of annealing temperature on the electrochemical properties for lithium ion batteries（LIBs） are assessed. The obtained LIB properties for TiO2 nanofiber anodes annealed at 400 ℃（denoted as TiO2/NFs-400） are much better than those of TiO2/NFs-500 and TiO2/NFs-600. The TiO2/NFs-400 anodes show good LIB performance with capacities of 180 and 150 m Ah/g tested at 200 and 600 m A/g after 100 cycles with almost no capacity loss and superb rate performance. The XRD results show that the pure anatase phase TiO2 can form at 400 ℃ for TiO2/NFs-400, while mixed phases of anatase and rutile are emerged at TiO2/NFs-500 and TiO2/NFs-600. Furthermore, the TiO2 nanoparticles are combined in nanofibers, and their corresponding crystal particle size for TiO2/NFs-400 was smaller than that of the other two samples. It is concluded that the superior electrochemical performance of the TiO2/NFs-400 anodes could be due to their pure crystal of anatase, small nanoparticles and non-ideal crystal lattices.

Comparison of Pharmacodynamic Property of Two Kinds of Betahistine Drugs

Betahistine drugs are widely used in vestibular compensation process. For theunderstanding of drugs＇ structural feature, two betahistine drugs＇ （betahistine hydrochloride andbetahistine methanesulfonate） structure and vibrational spectra were calculated within densityfunctional theory （DFT） method and comparisons have been made with histamine. The drugs＇interactions with the receptors were revealed by using the molecular docking methods. The resultsshow that the discrepancies of pharmacodynamic property would be resulted from minor molecularstructure difference, and the vibrational spectra can be used for monitoring the drugs＇metabolization. Generally, betahistine drugs have better performance in the docking patterns withreceptors, like stronger interactions, forming more hydrogen bonds with receptors than histamine,and the betahistine methanesulfonate is found out to be the best for body recovery as it did inclinical presentation.

Effect of TiO2 on the Photodegradation Mechanism of Poly(butylene succinate)

The photodegradation behaviors of poly（butylene succinate）（PBS） and TiO2/PBS nanocomposite were monitored over a period of six months. Material properties and aging mechanisms were studied and explored by various characterizations including 1HNMR, FTIR, XRD, mass spectrum, and TGA. The TiO2/PBS nanocomposite was found to be more thermally stable and mechanically robust than the PBS. During aging, crystal formation and the final crystal structure changed notably. Based on the characterization results, it is proposed that the polymer chains have cleaved at the ester linkage by the dissociation of O–H groups and the conversion of C=O to C–O bonds. It was also believed that polymer chain transfer took place, which resulted in the formation of C=C bonds and O–H groups, and the polyester changed to enol or polyether.

Urothermal Synthesis of Zeolitic Tetrazolate-imidazolate Frameworks

Urothermal method was firstly used to synthesize zeolitic tetrazolate-imidazolate frameworks. By using 2-imidazolidone hemihydrate(e-urea) as solvent, a new compound, namely ZTIF-17 with GIS topology, has been obtained by mixing 5,6-dimethylbenzimidazole and 5-ethylthiotrazole ligands, and characterized by powder and single-crystal X-ray diffraction, and thermogravimetric(TG) analyses. In addition, ZTIF-17 exhibited strong photoluminescence at room temperature. The result suggests that urothermal method is powerful to construct new kind of porous materials.

Synthesis and Characterization of Polyimides Based on Twisted Non-coplanar Backbone Containing Indolocarbazole

A diamine monomer(4,4’-(((5,11-dihydroindolo[3,2-b]carbazole-6,12-diyl)bis(4,l-phenyl-ene))bis(oxy))dianiline)containing a rigid conjugated indolocarbazole was designed and synthesized through a three-step reaction.A series of high-performance functional polyimides were prepared through simple condensation polymerization of the monomer with different industrial dianhydrides 6FDA,BTDA and ODPA,respectively,which exhibit superior thermal stability,good solubility in polar organic solvents and good mechanical properties.The glass transition temperature(T_(g))is above 334℃,and the 5%weight loss temperature(T_(d5%))of polyimides under nitrogen atmosphere falls in the range of 502〜526℃.The tensile strength and tensile modulus are 49.45~60.08 MPa and 1.4-1.6 GPa,respectively.In addition,the maximum fluorescence emission wavelength of polyimides in the NMP solution(0.02 mg/mL)are around 448 nm with blue light emission and 451 nm as film without significant red shift,which indicates the prepared polyimides process a certain application potential in high-performance flexible polymer optoelectronic devices.

Rationally designed ultrathin Ni(OH)_(2)/titanate nanosheet heterostructure for photocatalytic CO_(2) reduction

Dye-sensitized photocatalysis has been extensively studied for photocatalytic solar energy conversion due to the advantage in capturing long-wavelength photons with a high absorption coefficient.The rational integration of photosensitizer with semiconductor and cocatalyst to collaboratively operate in one system is highly desired.Here,we fabricate a Ni(OH)_(2)-loaded titanate nanosheet(Ni(OH)_(2)/H_(2)Ti_(6)O_(13))composite for high-performance dye-sensitized photocatalytic CO_(2) reduction.The ultrathin H_(2)Ti_(6)O_(13) nanosheets with negative surface charge provide an excellent support to anchor the dye photosensitizer,while the loaded Ni(OH)2 serves as an adsorbent of CO_(2) and electron sink of photoelectrons.As such,the photoelectrons derived from the[Ru(bpy)3]Cl_(2) sensitizer can be targeted transfer to the Ni(OH)_(2) active sites via the H_(2) Ti_(6)O_(13) nanosheets linker.A high CO production rate of 1801μmol g^(-1) h^(-1) is obtained over the optimal Ni(OH)_(2)/H_(2)Ti_(6)O_(13),while the pure H_(2)Ti_(6)O_(13) shows significantly lower CO_(2) reduction performance.The work is anticipated to trigger more research attention on the rational design and synthesis of earth-abundant transition metal-based cocatalysts decorated on ultrathin 2D platforms for artificially photocatalytic CO_(2) reduction.