Simultaneous morphology manipulation and upconversion luminescence enhancement of β-NaYF4:Yb3+/Er3+ microcrystals by simply tuning the KF dosage.

Mingye Ding,Zhongzi Xu,Jiasong Zhong,Chunhua Lu,Zhenguo Ji,Daqin Chen,Yaru Ni,Shilong Yin

doi:10.1038/srep12745

Abstract

A strategy has been adopted for simultaneous morphology manipulation and upconversion luminescence enhancement of β-NaYF4:Yb3+/Er3+ microcrystals by simply tuning the KF dosage. X-ray power diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and photoluminescence spectra (PL) were used to characterize the samples. The influence of molar ratio of KF to Y3+ on the crystal phase and morphology has been systematically investigated and discussed. It is found that the molar ratio of KF to Y3+ can strongly control the morphology of the as-synthesized β-NaYF4 samples because of the different capping effect of F− ions on the different crystal faces. The possible formation mechanism has been proposed on the basis of a series of time-dependent experiments. More importantly, the upconversion luminescence of β-NaYF4:Yb3+/Er3+ was greatly enhanced by increasing the molar ratio of KF to RE3+ (RE = Y, Yb, Er), which is attributed to the distortion of local crystal field symmetry around lanthanide ions through K+ ions doping. This synthetic methodology is expected to provide a new strategy for simultaneous morphology control and remarkable upconversion luminescence enhancement of yttrium fluorides, which may be applicable for other rare earth fluorides.

Highlights

A strategy has been adopted for simultaneous morphology manipulation and upconversion luminescence enhancement of β-NaYF4:Yb3+/Er3+ microcrystals by tuning the KF dosage
The other synthetic parameters were set as reaction temperature 220 °C, reaction time 24 h, Na3Cit 1 mmol
No trace of characteristic peaks is detected for other impurity peaks such as KYF4, YF3, indicating that the simple hydrothermal method is a feasible route to synthesize pure β -NaYF4 microcrystals using KF as fluoride source

Summary

Introduction

A strategy has been adopted for simultaneous morphology manipulation and upconversion luminescence enhancement of β-NaYF4:Yb3+/Er3+ microcrystals by tuning the KF dosage. Careful observation reveals that the relative diffraction peak intensity of XRD patterns varies with different molar ratio of KF to Y3+, implying the morphology evolution of as-prepared β -NaYF4 crystals.

Results

Conclusion