The internal modification with rare earth ion doping proved to be a very effective strategy for improving the luminescent properties of NaYF 4 -based upconversion materials. However, greatly enhancing the luminescence efficiency of NaYF 4 :Yb 3+ /Er 3+ remains a major challenge. Herein, the effects of Sn 4+ doping on the structure and luminescent performance of such material were explored. The hydrothermal molten-salt method was applied to synthesize the Sn 4+ -doped NaYF 4 :Yb 3+ /Er 3+ upconversion materials, and their crystal structures, morphologies, surface chemical composition and element states, and luminescence performance were characterized. It was found that Sn 4+ doping can significantly enhance the luminescence intensity and tailor the chromaticity of NaYF 4 :Yb 3+ /Er 3+ . In particular, the green (G) and red (R) luminescence intensity levels of the 30 mol% Sn 4+ doped material were increased by factors of 26.97 and 38.91, respectively. The R/G ratio was incremented from 0.34 for the undoped material to 0.83 for the 40 mol% Sn 4+ doped counterpart. The Sn 4+ doping led to the change of lattice distortion and crystal growth pattern of NaYF 4 :Yb 3+ /Er 3+ . The mechanism for Sn 4+ doping to affect the luminescence properties of the prepared upconversion material was also explored. The changes in luminescence intensity levels and R/G ratios could be attributed to the highly asymmetric distorted lattice and crystal field resulting from Sn 4+ doping.
Up-to-date laser-driven lightings confront a challenge of simultaneously achieving good photometric and chromatic performances. Herein, the coupling of “patterned package design” and “phosphor wheel” was proposed and demonstrated effectively to deal with this tough issue, based on a new architecture of CaAlSiN 3 :Eu 2+ (CASN:Eu) glass ceramic film (GCF) on Y 3 Al 5 O 12 :Ce 3+ (YAG:Ce) GC plate. The fabricated composite has no interface between the two functional layers and retains the admirable luminescent features from CASN:Eu and YAG:Ce for the microstructural integrity during co-sintering. The studies on laser-microcrystalline interactions reveal that the luminescence saturation is almost determined by thermal quenching for YAG:Ce, but is ascribed to thermal/intensity quenching which are equally crucial for CASN:Eu. Benefiting from the elaborate architecture design, good color chromaticity tunability was obtained, and severe photon reabsorption was reduced. Moreover, accompanied with the rotation induced increase of thermal convection to air and pulse-like excitation, the constructed lighting engine under blue laser driven shows bright white light with luminous flux (LF) higher than 1000 lm, adjustable chromaticity from cool to warm, and improved color rendering index (CRI) approaching to 70.
危险品化学品经营许可证（带存储）