Chinese Optics Letters, 2020, 18 (11): 110501, Published Online: Sep. 27, 2020
Screen printing of upconversion NaYF4:Yb3+/Eu3+ with Li+ doped for anti-counterfeiting application Download: 799次
upconversion micro-particles hydrothermal synthesis anti-counterfeiting identification screen printing
Abstract
Li ions affect the upconversion efficiency by changing the local crystal field of the luminescent center. Herein, in order to improve the upconversion efficiency of NaYF4:Yb3+/Eu3+, a series of NaYF4:Yb3+/Eu3+ micro-particles with different Li+ doping concentrations were synthesized by the hydrothermal synthesis method, respectively. Firstly, the structure and morphology of NaYF4:Yb3+/Eu3+ upconversion micro-particles (UCMPs) with different doping concentrations were analyzed by X-ray diffraction and a scanning electron microscope (SEM). SEM results show that the UCMPs are not only highly crystallized, but also have hexagons with different Li+ concentrations of NaYF4:Yb3+/Eu3+. X-ray diffraction shows that the crystal field around Eu3+ changes with the increase of Li+ concentration. Then, the fluorescence spectrum of NaYF4:Yb3+/Eu3+ was studied under the irradiation of a 980 nm laser. The results show that the fluorescence intensity of NaYF4:Yb3+/Eu3+ with 2% Li+ is the strongest, which is twice the intensity of NaYF4:Yb3+/Eu3+ without Li+. Finally, the fluorescence imaging analysis of NaYF4:Yb3+/Eu3+ with 2% Li+ concentration was carried out. The UCMPs are used to screen printing to evaluate the imaging effect on different sample surfaces. The results show NaYF4:Yb3+/Eu3+ (with 2% Li+) has great application prospects in anti-counterfeiting recognition.
Dongdong Li, Jianye Mo, Chong Wang, Wei Liu, Haibo Ge, Dongdong Han, Aihua Hao, Baoyu Chai, Jiangbo She. Screen printing of upconversion NaYF4:Yb3+/Eu3+ with Li+ doped for anti-counterfeiting application[J]. Chinese Optics Letters, 2020, 18(11): 110501.