Hydrothermal synthesis and luminescence properties of octahedral LiYbF{sub 4}: Er{sup 3+} microcrystals

Journal Article · Tue Feb 15 04:00:00 EST 2011 · Materials Research Bulletin

DOI:https://doi.org/10.1016/J.MATERRESBULL.2010.11.008· OSTI ID:22209995

Lu, Chunhua ^[1]; Huang, Wenjuan; Ni, Yaru; Xu, Zhongzi ^[1]

---

1. State Key Laboratory of Materials-Orient Chemical Engineering, College of Materials Science and Engineering, Nanjing University of Technology, Gulou District, Nanjing 210009 (China)

Graphical abstract: LiYbF{sub 4}: Er{sup 3+} octahedral microcrystals have been successfully prepared through a facile hydrothermal method assisted with EDTA. SEM, HRTEM, RD, PL spectra are used to characterize the samples. It can be seen from SEM data that the complexing agent EDTA made to hydrothermal synthetic procedures result in formation of LiYbF{sub 4} octahedral microparticles with smooth surface. From the HRTEM images, the distances between the lattice fringes were measured to be 2.99 A and 2.57 A which correspond to the d-spacing for (1 1 2) and (2 0 0) planes, respectively. From the XRD patterns for the LiYb{sub 0.99}Er{sub 0.01}F{sub 4} in the absence of chelating agent EDTA and in the presence of EDTA, it is evident that the diffraction peaks of both patterns are highly crystalline and all of the peaks could be readily indexed to the LiYbF{sub 4} phase (JCPDS 71-1211). No other impurity peaks were detected. Under 976 nm excitation, the upconversion (UC) luminescence emission spectra of LiYbF{sub 4}: Er{sup 3+} microcrystals show the characteristic Er{sup 3+} emissions. The results show that the infrared light emissions at 792 nm of {sup 4}I{sub 9/2} {yields} {sup 4}I{sub 15/2} are dominantly strong unusually, while the green emissions at 526 and 545 nm assigned to {sup 2}H{sub 11/2} {yields} {sup 4}I{sub 15/2} and {sup 4}S{sub 3/2} {yields} {sup 4}I{sub 15/2}, respectively, and the red emission at 667 nm of {sup 4}F{sub 9/2} {yields} {sup 4}I{sub 15/2} are relatively weaker. Research highlights: {yields} Monodisperse and regular octahedral microcrystals LiYbF{sub 4}: Er{sup 3+} with smooth surface has been prepared. {yields} The characteristic emissions of Er{sup 3+} ions are observed in LiYbF{sub 4} microcrystals. {yields} The content of EDTA will influence the fluorescence intensity. {yields} Luminescence intensity increases gradually at the beginning and then decreases gradually with increasing temperature. -- Abstract: LiYbF{sub 4}: Er{sup 3+} octahedral microcrystals have been successfully prepared through a facile hydrothermal method assisted with EDTA (ethylenediaminetetraacetic acid). X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric and differential scanning calorimeters (TG-DSC), photoluminescence (PL) spectra are used to characterize the samples. Under 976 nm excitation, the upconversion (UC) luminescence emission spectra of LiYbF{sub 4}: Er{sup 3+} microcrystals show the characteristic Er{sup 3+} emissions. The results show that the infrared light emissions at 792 nm of {sup 4}I{sub 9/2} {yields} {sup 4}I{sub 15/2} are dominantly strong unusually, while the green emissions at 526 and 545 nm assigned to {sup 2}H{sub 11/2} {yields} {sup 4}I{sub 15/2} and {sup 4}S{sub 3/2} {yields} {sup 4}I{sub 15/2}, respectively, and the red emission at 667 nm of {sup 4}F{sub 9/2}{yields}{sup 4}I{sub 15/2} are relatively weaker. Most importantly, the samples show more efficient luminescence with further heat treatment.

• OSTI ID: 22209995
• Journal Information: Materials Research Bulletin, Journal Name: Materials Research Bulletin Journal Issue: 2 Vol. 46; ISSN MRBUAC; ISSN 0025-5408
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
CALORIMETRY
CRYSTALS
EDTA
EMISSION SPECTRA
ERBIUM IONS
FLUORESCENCE
FOURIER TRANSFORM SPECTROMETERS
FOURIER TRANSFORMATION
HYDROTHERMAL SYNTHESIS
INFRARED SPECTRA
MICROSTRUCTURE
PHOTOLUMINESCENCE
SCANNING ELECTRON MICROSCOPY
SURFACES
THERMAL GRAVIMETRIC ANALYSIS
TRANSMISSION ELECTRON MICROSCOPY
X-RAY DIFFRACTION