Design and electrospinning synthesis of SrF2:Er3+/Yb3+ unidimensional nanostructural materials with tunable upconverting fluorescence

Abstract

In order to develop new morphology and properties of up-converting fluorescent materials, SrF2:Er3+/Yb3+ up-converting fluorescent unidimensional nanostructural materials including nanofibres, nanostrips and hollow nanofibres have been designed and successfully constructed via a uniaxial electrospinning associated with a bi-crucible fluorination technology. Controllable fabrication of unidimensional nanostructural materials is successfully realized via controlling the ingredients and proportions of the spinning solutions and spinning parameters. The influences of roasting temperature, molar proportion of Yb3+ to Er3+ and morphology on the up-converting fluorescence of the samples are studied in detail, and further tunable fluorescence is achieved. Upon the excitation of 980-nm laser, the unidimensional nanostructural materials display excellent up-converting fluorescence. The bright green emissions at 526 and 548 nm are assigned to the 2H11/2 → 4I15/2 and 4S3/2 → 4I15/2 energy levels transition of the Er3+ ions, respectively, and the weaker red characteristic emission peak at 652 nm is attributed to the 4F9/2 → 4I15/2 energy level transition of Er3+. Further, the detailed fluorescent mechanism and the formative mechanism of the unidimensional nanostructural materials are expounded in-depth, and the fabrication techniques are built. Much more importantly, the designing philosophy and fabricating technology can be popularized to manufacture other metal fluoride unidimensional nanostructural materials. The as-synthesized SrF2:Er3+/Yb3+ unidimensional nanostructural materials may find tremendous potential applications in the areas of emitting diodes, displaying devices, optical probes, bioimaging, sensing, drug delivery and lithium-sulfur batteries.