Crystal growth, structure and physical properties of Ln(CuGa)₁₃compounds (Ln = La–Nd, Eu)

Abstract

For the past two decades, research about metal silicate and phosphate with microporous structure has always played an important role in the field of materials chemistry due to their wide application potential from traditional catalyst, molecular sieve and ion exchange to recently developed low-k materials and zeolitic dye laser. In recent years, we have discovered several gallium phosphates containing transition metal with pore size around 1 nm and intriguing photoluminescence property. For example, 24-member ring NTHU-11 and the first organo-metallo phosphates NTHU-2,2 can emit blue light when excited with UV light. The photoluminescence phenomenon is a new property of nanoporous metal phosphate with emission mechanism apparently different from that of existing inorganic phosphor since the later is doped with metal activator or added with sensitizer in host lattice in order to illuminate. At present, the photoluminescence property of nanoporous metal phosphate is substantiated. Besides blue light, zinc gallophosphate that can emit yellow light or even white light have been synthesized. In this presentation, we are going to present a serious of nanoporous gallophosphates and zinc gallophosphates via the synthetic strategy of employing the large 4,4'-trimethylenedipyridine (tmdp) amine as a template. Their structures will be described and photoluminescence property will be examined.

Strategic Crystal Growth and Physical Properties of Single-Crystalline LnCo2Al8 (Ln = La–Nd, Sm, Yb)

“…6,7 For example, Ln(Cu, Ga) 13-x (Ln = La-Nd, Eu) (NaZn 13 -structure type) can be prepared with early lanthanides up to Nd. 8 The Eu analogue also forms, given the larger cationic radii and the divalent state of Eu. Surprisingly, the Pr-analogue exhibits a large positive magnetoresistance up to 154% at 2 K with an application of magnetic field and a large electronic contribution to the heat capacity, C p = γT + βT 3 , with γ ~ 100 mJ / mol-K 2 .…”