The Effects of Halogen Exchange on the Structural Features, Thermal Behavior and Photoluminescence of Y/Eu Layered Rare-Earth Hydroxide (LRH) Nanosheets

摘要

Solid-solution nanosheets (down to ～5 nm thick, in the form of flower like assemblies) of the (Y_(0.95)Eu_(0.05))_2NO_3·nH_2O were directly synthesized via chemical precipitation at the freezing temperature of ～4°C. In situ exchange of the interlayer NO_3~- with halogen anions produced a series of halogen derivatives (Y_(0.95)Eu_(0.05))_2X·nH_2O (X= F~-, Cl~-, Br~- and I~-) of the same layered structure and two-dimensional crystallite morphology. The basal spacing of the derivatives was discussed from the geometric size/spatial orientation of the anions and also from anion-host interaction via electrostatic attraction and hydrogen bonding. The thermal behavior and photoluminescence spectroscopies were found to be strongly related to the anion-host interactions.