Controllable synthesis of Sn0.33WO3 tungsten bronze nanocrystals and its application for upconversion luminescence enhancement

The development and utilization of novel semiconductor nanocrystals with remarkable localized surface plasmon resonance (LSPR) effect is one of the current research hotspots. Tungsten bronze nanocrystals are a class of semiconductor nanocrystals with strong LSPR effect discovered recently. The synthesis of tungsten bronze nanocrystals by introducing high valence metal ions, the regulation and application of the corresponding LSPR effect are still under further exploration. In this paper, Sn0.33WO3 nanocrystals with different crystal phases and morphologies were synthesized using different types of Sn precursors and different amounts of NH4F. Acid radical ions provided by different types of Sn precursors is an important factor affecting the LSPR absorption characteristics of Sn0.33WO3 nanocrystals. Sn0.33WO3 nanosheets with strong LSPR absorption synthesized with stannous oxalate were used as a representative to enhance the upconversion luminescence of NaYF4:Yb3+, Er3+. Compared with Glass/NaYF4:Yb3+, Er3+ film, the upconversion luminescence intensity of the layered Glass/Sn0.33WO3/PMMA/NaYF4:Yb3+, Er3+ film was enhanced by 34 times. The LSPR effect of Sn0.33WO3 enhances the excitation field of NaYF4:Yb3+, Er3+ nanocrystals, resulting in significant upconversion luminescence enhancement of NaYF4:Yb3+, Er3+ in the layered Glass/Sn0.33WO3/PMMA/NaYF4:Yb3+, Er3+ film. The present work is helpful for people to study the development and application of semiconductor nanocrystals with LSPR effect.