Ionic liquid-assisted hydrothermal synthesis and excitation wavelength-dependent luminescence of YBO3:Eu3+ nano-/micro-crystals

Three dimensional (3D) architectures YBO3:Eu3+ phosphors were prepared via ionic liquid-assisted hydrothermal process and characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM) and photoluminescence (PL). The pH value and ionic liquid play an important role in the control of morphology of products. By comparing with the corresponding bulk, the tyre-like YBO3: 5 mol%Eu3+ microspheres demonstrate a red shift of the charge transfer band (CTB), appearance of a long excitation tail at the long wavelength side of the CTB and high improved chromaticity. Two Eu3+ environments in the tyre-like sample, namely interior and outside Eu3+, were found by selective excitation under the different wavelength light. Finally, fluorescent decays and Judd-Ofelt (J-O) theory were utilized to analyze the local crystal environments around Eu3+ ions in the tyre-like and bulk phosphors. (C) 2013 Elsevier B. V. All rights reserved.