Upcoversion performance improvement of NaYF4:Yb, Er by Sn codoping: Enhanced emission intensity and reduced decay time

• NaYF4: Yb, Er was codoped with different concentration Sn.
• Upconversion emission intensity was enhanced while decay time constant was decreased.
• Introduction of variable-valenced Sn is effective to tune structure and crystal field of NaFY4.

In this manuscript we report a phenomenon that upconversion emission intensity of Er3+ was enhanced while decay time constant was decreased obviously by Sn codoping with Yb/Er into hexagonal NaYF4 synchronously. X-ray powder diffiraction, field emission scanning electron microscope, transmission electron microscopy, X-ray photoelectron spectroscopy, electron spin-resonance spectroscopy and upconversion emission spectra were employed to explore the relation of crystal structure and properties. From these characterizations we found that symmetry of the rare earth ion local crystal field could be tuned by different Sn codoping concentration. For the variable valence property of Sn the local crystal field asymmetry and emission intensity of NaYF4:Yb, Er arrived to the maximum when 3 mol% Sn was codoped, while decay time was reduced. The study of this changing tends of upconversion emission intensity and decay time constant may be helpful for design and fabrication of high performance upconversion materials.

Variable-valenced Sn is introduced with Yb/Er into NaFY4 to tune structure and local crystal field. Upconversion emission intensity of Er3+ was enhanced while decay time constant was decreased.Figure optionsDownload as PowerPoint slide