Brucite structure doped with different amounts of Er(III) and their infrared emissions

Abstract

A series of brucite structure-doped samples with different amounts of Er(III) have been synthesized by hydrothermal method. Various characterizations have been employed to study the composition, structure, and photoluminescence. Results suggested that the Er3+-doped samples with Mg(II)/Er(III) molar ratio of 0.99/0.01~0.8/0.2 exhibited typical brucite structure, and the sample with Mg(II)/Er(III) molar ratio of 0.7/0.3 represented layered double hydroxide (LDH) structure. Moreover, the crystallinity of the Er3+-doped samples tended to be poorer with the increasing amount of Er(III). Various strong emissions ranging from red to infrared emissions appear in the down-conversion photoluminescent spectra of the Er3+-doped samples excited by different wavelengths, and the energy of emission peaks has linear dependence on the energy of the excitation wavelength at 450~565 nm. Photoluminescent decay spectra show that the decaying behavior of the red and infrared emissions for the Er3+-doped samples are different from that of the previous Er3+-doped materials, and the lifetimes of the red and infrared emissions are less than that of the other Er3+-doped materials. Based on the present results as well as relevant references, the energy transition diagrams of the Er(III) incorporated in the samples were described, and the transition mechanisms of the red and infrared emissions have been proposed. The new Er3+-doped materials may be a latent fluorescent material applied in NIR detector or biomedical imaging in view of its strong red and infrared emissions as well as less toxicity for organisms.