Synthesis of Upconversion β-NaYF₄:Nd3+/Yb3+/Er3+ Particles with Enhanced Luminescent Intensity through Control of Morphology and Phase

Yunfei Shang; Shuwei Hao; Jing Liu; Meiling Tan; Ning Wang; Chunhui Yang; Guanying Chen

doi:10.3390/nano5010218

Synthesis of Upconversion β-NaYF₄:Nd³⁺/Yb³⁺/Er³⁺ Particles with Enhanced Luminescent Intensity through Control of Morphology and Phase

Nanomaterials (Basel). 2015 Feb 24;5(1):218-232. doi: 10.3390/nano5010218.

Authors

Yunfei Shang¹, Shuwei Hao², Jing Liu³, Meiling Tan⁴, Ning Wang⁵, Chunhui Yang^{6

7}, Guanying Chen^{8

9}

Affiliations

¹ School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001, China. syf19943@sina.com.
² School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001, China. haoshuwei031011@126.com.
³ School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001, China. jing43210@163.com.
⁴ School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001, China. tanmeiling828@163.com.
⁵ School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001, China. wangning9004@sina.com.
⁶ School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001, China. yangchh@hit.edu.cn.
⁷ Harbin Huigong Technology Co. Ltd, Harbin 150001, China. yangchh@hit.edu.cn.
⁸ School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001, China. chenguanying@hit.edu.cn.
⁹ Institute for Lasers, Photonics and Biophotonics, University at Buffalo, The State University of New York, Buffalo, NY 14260, USA. chenguanying@hit.edu.cn.

Abstract

Hexagonal NaYF₄:Nd³⁺/Yb³⁺/Er³⁺ microcrystals and nanocrystals with well-defined morphologies and sizes have been synthesized via a hydrothermal route. The rational control of initial reaction conditions can not only result in upconversion (UC) micro and nanocrystals with varying morphologies, but also can produce enhanced and tailored upconversion emissions from the Yb³⁺/Er³⁺ ion pairs sensitized by the Nd³⁺ ions. The increase of reaction time converts the phase of NaYF₄:Nd³⁺/Yb³⁺/Er³⁺ particles from the cubic to the hexagonal structure. The added amount of oleic acid plays a critical role in the shape evolution of the final products due to their preferential attachment to some crystal planes. The adjustment of the molar ratio of F^-/Ln³⁺ can range the morphologies of the β-NaYF₄:Nd³⁺/Yb³⁺/Er³⁺ microcrystals from spheres to nanorods. When excited by 808 nm infrared laser, β-NaYF₄:Nd³⁺/Yb³⁺/Er³⁺ microplates exhibit a much stronger UC emission intensity than particles with other morphologies. This phase- and morphology-dependent UC emission holds promise for applications in photonic devices and biological studies.

Keywords: NaYF4 microcrystals; Nd3+ sensitizer; morphology control; upconversion (UC).