Structure, Delamination and Luminescence of Layered Dysprosium Hydroxides and the Generation of White Light with 2D Crystals

Abstract

Layered dysprosium hydroxides intercalated with dodecyl sulfate ions (DS−LDyHs) have been synthesized using homogenous precipitation technique. Unlike the previously reported DS− intercalated layered europium hydroxides (DS−-LEuHs) and layered terbium hydroxides (DS−-LTbHs), the resultant DS−-LDyHs have mixed host layers of m=1 and m=2 according to the general formula of Dy2(OH)6-m(Ax−)m/x⋅nH2O. Due to charge difference, the m=1 and 2 types of layers have different basal spacings of ∼28 and ∼34 Å, corresponding to a monolayer and an alternating antiparallel arrangements of DS− in the interlayers, respectively. Unlike their precursors, the 2D crystals exhibit strong 4F9/2→6H13/2 hypersensitive emissions of Dy3+, making them more applicable to the generation of white-bluish lights. The nanosheets also have longer fluorescence lifetime than precursor for 480 nm emission of Dy3+. Colloidal hybrids were prepared by mixing a suspension of the nanosheets of DS−-LDyHs, DS−-LEuHs and DS−-LTbHs to achieve color-tuning in the white-light region under excitations at 284, 318, and 377 nm.