Size-tunable synthesis and luminescent properties of Gd(OH)3:Eu3+ and Gd2O3:Eu3+ hexagonal nano-/microprisms
Abstract
Uniform and monodisperse Gd(OH)3:Eu3+ hexagonal prisms were successfully synthesized at mild conditions via a large-scale and facile homogeneous coprecipitation process without using any catalysts, surfactants or templates. The size of the as-formed Gd(OH)3:Eu3+ precursor prisms could be modulated from the micro- to nanoscale by the use of urea and changing the pH values of the initial solutions. A possible formation mechanism for the Gd(OH)3:Eu3+ hexagonal nano-/microprisms was proposed. After a postannealing process, Gd2O3:Eu3+ hexagonal nano-/microprism phosphors with a slight shrinking in size can be transformed from Gd(OH)3:Eu3+. Both the Gd2O3:Eu3+ nanoprisms and microprisms exhibit the same strong red emission corresponding to the 5D0 → 7F2 transition (610 nm) of Eu3+ under UV light excitation (243 nm) and low-voltage electron beam excitation (1–6 kV). Furthermore, the experimental results indicate that the luminescence properties of the as-obtained phosphors are dependent on their morphologies and sizes. As a result of the controllable morphology and size, and excellent luminescence properties, these Gd2O3:Eu3+ nano-/microprism phosphors may find potential applications in optoelectronic devices (fluorescent lamps and field emission displays), bioanalysis and biomedical areas and so on.