Hailing Guo

Fabrication of hierarchical architectures of Tb-MOF by a “green coordination modulation method” for the sensing of heavy metal ions

A green coordination modulation method has been successfully exploited to fabricate lanthanide coordination polymer Tb(BTC)(H2O) via environmentally friendly ethanol and alkaline additive. Fascinating hierarchical architectures, including rod-like crystals, dual-core shelled peanut-like crystals and double-head dandelion-like crystals were obtained through exploring the reaction parameters. The structures of the samples were confirmed by powder X-ray diffraction, and the morphologies were characterized by SEM. Furthermore, details of the formation mechanism of the resulting crystal morphologies were deduced. The studies of the photoluminescence properties reveal that the hierarchical architectures of these coordination polymers exhibit green emission, corresponding to the 5D4/7FJ (J = 6, 5, 4, 3) transitions of the Tb3+ ions under UV light excitation. Outstandingly, double-head dandelion-like crystals with the strongest photoluminescence intensity display highly sensitive and selective sensing for heavy metal ions, and the probable sensing mechanism was discussed.

Hydrothermal synthesis and upconversion photoluminescence properties of lanthanide doped YF3 sub-microflowers

Yttrium fluoride sub-microflowers were synthesized by facile hydrothermal route without using any expensive or environmental unfriendly agents. The influences of various hydrothermal parameters on the final products were investigated. It was found that the concentration of NH3·H2O had a significant effect on the morphology change of YF3 sub-microcrystals. The growth mechanism of the as-obtained YF3 sub-microflowers was proposed. The multicolor upconversion (UC) photoluminescence (PL) was successfully realized in Yb3+/Tm3+, Yb3+/Ho3+ and Yb3+/Er3+ doped YF3 sub-microflowers when excited by 980 nm laser diode (LD). The pumping power dependence of the fluorescent intensity is investigated to understand the fundamental UC mechanism.