Sol-hydrothermal synthesis and optical properties of Eu3+, Tb3+-codoped one-dimensional strontium germanate full color nano-phosphors

Abstract

Novel near-UV and blue excited Eu³⁺, Tb³⁺-codoped one dimensional strontium germanate full-color nano-phosphors have been successfully synthesized by a simple sol-hydrothermal method. The morphologies, internal structures, chemical constitution and optical properties of the resulting samples were characterized using FE-SEM, TEM, HRTEM, EDS, XRD, FTIR, XPS, PL and PLE spectroscopy and luminescence decay curves. The results suggested that the obtained Eu³⁺, Tb³⁺-codoped strontium germanate nanowires are single crystal nanowires with a diameter ranging from 10 to 80 nm, average diameter of around 30 nm and the length ranging from tens to hundreds micrometers. The results of PL and PLE spectra indicated that the Eu³⁺, Tb³⁺-codoped single crystal strontium germanate nanowires showed an intensive blue, blue-green, green, orange and red or green, orange and red light emission under excitation at 350–380 nm and 485 nm, respectively, which may attributed to the coexistent Eu³⁺, Eu²⁺ and Tb³⁺ ions, and the defects located in the strontium germanate nanowires. A possible mechanism of energy transfer among the host, Eu³⁺ and Tb³⁺ ions was proposed. White-emission can be realized in a single-phase strontium germanate nanowire host by codoping with Tb³⁺ and Eu³⁺ ions. The Eu³⁺, Tb³⁺-codoped one-dimensional strontium germanate full-color nano-phosphors have superior stability under electron bombardment. Because of their strong PL intensity, good CIE chromaticity and stability, the novel 1D strontium germanate full-color nano-phosphors have potential applications in W-LEDs.