Study On Regulation Of Bismuth-Activated Luminescent Materials By Topo-chemical Reduction

Photoluminescence caused by the bismuth formed by the optically active center has been extensively studied. The understanding of the luminescence mechanism has a deep guiding significance for practical application. However, based on the diversity of the host material, and the bismuth element itself has the characteristics of multi-valence state,bismuth-containing material luminescence performance is still a lot of unknown factors. In addition, the traditional high temperature solid phase synthesis method is suitable for the synthesis of thermodynamically stable phase, and can not synthesize the metastable phase.The local regulation strategy as a mild chemical synthesis route, can reasonably design the structure and composition of the required stability. In this paper, we use the rare earth oxide as the matrix, the local regularization reaction to develop the metastable phase of bismuth doped materials, and by adjusting the concentration of oxygen vacancy to control the visible and near infrared optical properties of bismuth, to study the corresponding luminescence mechanism. In this paper, the composition and structure of the oxygen-deficient phase were characterized by thermogravimetric analysis, X-ray absorption spectroscopy, X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy, fluorescence spectroscopy, UV-Vis absorption spectroscopy and quantum chemical calculation As well as the performance of light and so on a comprehensive, in-depth and systematic research. The main results of this paper are as follows:?1? We use Bi-doped LU₂O₃ as a model to present and explain the concept of "oxygen vacancy-dominated chemical stress release",and we demonstrate that this is a generally effective method to significantly improve PL emission of size mismatched doped phosphors.Composition, structure and PL characterization, coupled with quantum chemical calculations, reveals that the presence of adjacent Bi3+ ions in the oxygen space promotes the release of the doped region. The chemical stress of the domain causes the dark emitter to be converted into a bright emitter.?2? We use Bi-doped Gd₂O₃ to use local chemical reduction to produce a new class of luminescent materials and exhibit ultra-high near-infrared PL, which can cover the second biological window. It is expected that the novel system can be applied to imaging in vitro /in vivo near infrared fluorescence in a second biological window. We also expect that more systems with excellent luminescent properties can be developed by using local chemical reduction reactions.